Ultra-Lightweight Borosilicate Filler with SiO₂ ≥ 72.0% · True Density 0.22–0.55 g/cm³ · D50 30–60 µm
Hollow Glass Microspheres (HGM) are ultra-lightweight fillers made of borosilicate glass whose main chemical component is silica (SiO₂) at 72.0% or higher. Their structure consists of hollow spheres encapsulated by micrometer-sized glass walls, with the internal cavity filled with nitrogen gas; the appearance is a white powder. Though an inorganic non-metallic material, its density is far below that of water, earning it the name "space material of the new era".
With a true density of 0.22–0.55 g/cm³ and bulk density of 0.13–0.35 g/cm³, HGM dramatically reduces the weight of compounds compared with conventional fillers such as calcium carbonate or talc, and its floatation rate exceeds 95%. Despite this, compressive strength reaches 30–80 MPa, so the spheres survive injection, extrusion and high-shear mixing without crushing. D50 particle size is 30–60 µm; the composition of SiO₂ ≥ 72.0% and Al₂O₃ 5.0–12.0% provides excellent chemical stability and corrosion resistance, while moisture ≤ 0.30%, whiteness ≥ 88.0 and a neutral pH of 7.0–9.0 make it compatible with most resin and waterborne systems.
The spherical geometry produces a ball-bearing effect that lowers compound viscosity and improves flow and dispersion, while the internal nitrogen layer delivers low thermal conductivity and outstanding insulation. Low dielectric constant and low dielectric loss make it well suited to 5G components and low-Dk printed circuit boards, and it also offers self-lubrication, sound insulation, non-water absorption, fire resistance and corrosion resistance.
Grades run from HN10 through HN60, plus high-strength types HN46HS, HN60HS, HN16K and HN18K, combining different density and compressive strength targets; supply is tailored to the recommended grade for each application.
Key Features
- 🪶 Ultra-Low Density (0.22–0.55 g/cm³) — Hollow structure lighter than water delivers weight reduction and cost savings
- 💪 Compressive Strength 30–80 MPa — Survives high-pressure injection and extrusion without crushing despite its light weight
- 🧊 Low Thermal Conductivity — The internal nitrogen layer blocks heat transfer — ideal for insulating coatings and materials
- 📡 Low Dielectric Constant — Functional filler for 5G components, low-Dk PCBs and composite substrates
- 🌀 Ball-Bearing Effect — Perfectly spherical particles lower viscosity and improve dispersion and moldability
- 🛡️ Non-Absorbent · Fire & Corrosion Resistant — Moisture ≤0.30%, whiteness ≥88.0, neutral pH 7–9 with excellent chemical stability
Technical Specifications
| Item | Value | Note |
|---|---|---|
| Product Name | Hollow Glass Microspheres (HGM) | |
| Material | Alkaline-rich borosilicate glass | |
| Silicon Dioxide (SiO₂) | ≥ 72.0 % | Main chemical component forming the glass network |
| Aluminium Oxide (Al₂O₃) | 5.0 ~ 12.0 % | Reinforces chemical durability and strength |
| True Density | 0.22–0.55 g/cm³ | |
| Bulk Density | 0.13–0.35 g/cm³ | |
| D50 Particle Size | 30–60 µm | |
| Floatation Rate | ≥ 95 % | Indicator of hollow-sphere content |
| Compressive Strength | 30–80 MPa | |
| Moisture Content | ≤ 0.30% | |
| Whiteness | ≥ 88.0 | |
| pH Value | 7.0–9.0 | |
| Internal Gas | Nitrogen (N₂) | |
| Appearance | White powder (perfectly spherical hollow particles) | |
| Grades | HN10 · HN16 · HN20 · HN25 · HN32 · HN38 · HN40 · HN46 · HN60 / High-strength: HN46HS · HN60HS · HN16K · HN18K | |
| Origin | China | |
| Packaging | Lightweight kraft bags · big bags · OEM |
Product Lineup
- HN10 / HN16 / HN20 — Lowest density — aerospace auxiliaries, inorganic insulation board, lightweight furniture / wood substitute, ship putty
- HN25 / HN32 / HN38 / HN40 — General purpose — adhesives/sealants, insulating coatings, artificial stone, putty/patch, tooling plate, tile mortar
- HN46 / HN60 — High strength — SMC/BMC, injection & extrusion moulding, insulated pipe, syntactic foam, deep-sea buoyancy
- HN46HS / HN60HS / HN16K / HN18K — Ultra-high strength — 5G low-Dk plastics, composite PCB, oil-well cementing, low-density drilling fluid
Parent Category: Applied & Related Silica Materials
Particle size, purity, surface treatment and packaging can be customized to your specification. Contact us for samples, TDS and quotations.