CH83-1 series · colloidal SiO₂

Colloidal silica (silica sol)

An alkaline colloidal silica with a faint blue opalescence. The particles are discrete spheres of SiO₂ with a high specific surface area and negatively charged silanol groups. When the sol dries, the particles condense through siloxane bonds into a clear film that no longer dissolves in water.

Colloidal silica sol: a near-transparent liquid with a faint blue opalescence — Illustration (AI-generated): colloidal silica, near-transparent with a faint blue opalescence.

Grades and typical properties

Grade	SiO₂ %	Stabiliser	Stabiliser %	pH	Density 20 °C, g/cm³	Viscosity 20 °C, mPa·s	Avg. particle, nm
CH83-120	20 ± 1	Na₂O	≤ 0.25	8.5–9.5	1.120–1.140	2.5–3.0	8–10
CH83-120C	20 ± 1	Na₂O	≤ 0.20	8.5–9.0	1.120–1.140	2.0–2.8	4–5
CH83-123	23 ± 2	Na₂O	≤ 0.30	8.5–11	1.150–1.170	2.5–6.0	8–10
CH83-125	25 ± 2	Na₂O	≤ 0.30	9.0–11	1.165–1.170	3.0–6.0	8–10
CH83-130	30 ± 2	Na₂O	≤ 0.35	9.0–11	1.170–1.200	4.0–7.5	10–15
CH83-1050	15 ± 1	–	–	9.5–11	–	–	3–5
CH83-A30 acidic	30 ± 2	Na₂O	≤ 0.05	2.0–4.0	1.190–1.210	4.0–7.5	8–15
CH83-A1030 acidic, large particle	30 ± 2	Na₂O	≤ 0.05	2.0–4.0	1.190–1.210	4.0–7.5	80–100

Typical values, not a specification. Each shipment is supplied against the current TDS. Special-purpose grades can be developed to customer requirements.

Average particle size of CH83-1 grades, drawn to scale. For ranges, the solid circle shows the upper limit and the dashed circle the lower limit. Smaller particles penetrate further and bond more strongly; 10–15 nm and below gives the best long-term storage stability in coatings (see the stability guide). Not drawn: CH83-A1030 at 80–100 nm would be about eight times the largest circle here; see large-particle silica sol.

Where it is used

Coatings

Interior and exterior latex paints, primers and sealers, elastic and textured coatings, and stone-effect finishes. It also goes into functional coatings: fire-retardant, heat-resistant, waterproof, anti-corrosion, zinc-rich and road-marking paints. Combined with lithium or potassium silicate it forms purely inorganic coatings.

Investment casting

CH83-130 (30% SiO₂, low Na₂O) is also supplied as a binder for ceramic shell moulds. Ask for the data sheet.

Refractories

A high-temperature binder for kiln linings and insulation, aluminosilicate fibre, and refractory bricks made from clay, alumina or zirconia, in service at 1200–1700 °C. Refractory use →

Electrostatic flocking

Electro-finishing of flock fibres at around 10–12% addition. Treated fibres separate well and are antistatic. Flocking →

Paper & board

Transparent anti-slip coatings, microparticle retention and drainage, and coated papers. Paper & board →

Polishing

A polishing medium for glass, stone and metal surfaces. For a higher removal rate, see large-particle silica sol.

Textile finishing

An additive in easy-care and anti-slip finishing baths, used with resins and emulsions. Fabric finishing →

Wool spinning

A spinning aid at 2–5%. It raises fibre cohesion, giving fewer breaks and less fly loss. Wool spinning →

Anti-fog coatings

Hydrophilic, transparent anti-fog and anti-drip coatings for films and glass. Anti-fog →

Agriculture

A nano-silica source for silicon fertilizer formulators. Silicon fertilizer →

Steel & catalysts

Inorganic insulating coatings on cold-rolled silicon steel, and a binder for molecular sieves and catalyst carriers.

Dilution calculator

Silica sol is usually diluted with deionised water to a target SiO₂ content before use. Enter the batch size and the two concentrations.

Sol quantity (kg)

Starting SiO₂ (%)

Target SiO₂ (%)

This is a mass balance only. Add water slowly while stirring, and check pH and stability in your own system.

Frequently asked questions

Which CH83-1 grade should I start with?

For general coatings work, start with CH83-120 or CH83-125. If you need maximum penetration and a small particle size, use CH83-120C (4–5 nm). For high-solids binder work such as investment casting shells and refractories, use CH83-130 (30% SiO₂). For acidic systems or minimum sodium, use CH83-A30. Send us your application and we will recommend a grade and provide a sample.

What is the difference between the alkaline and the acidic grades?

The alkaline grades (CH83-120 to CH83-130, CH83-1050) are sodium-stabilised at pH 8.5–11. The acidic grades CH83-A30 and CH83-A1030 run at pH 2–4 with Na₂O ≤ 0.05%. Choose them for acidic systems or where residual sodium is a problem, for example in high-temperature binders.

How should colloidal silica be stored?

Store indoors at 1–45 °C and protect it from frost. Freezing destabilises the sol. Keep containers closed so that water does not evaporate, because concentrating the sol can lead to gelation.

Is CH83-1 classified as hazardous for transport?

CH83-1 is non-hazardous for road, sea and air transport (ADR, IMDG, IATA). An SDS is available on request.

What packaging is available?

We supply 140 kg plastic drums and 1200 kg IBC containers as standard. Other packaging is available on request.

Need the full TDS or a trial sample?

Tell us your application and target spec. Our technical team replies within one working day.

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