Foaming Agents & Density Modifiers
Engineered foam for lightweight, dimensionally stable board cores.
Board weight is decided in the foam generator, not in the mixer. Surfactant chemistry, air-to-water ratio at the generator, and mixer transit together set bubble size distribution, foam half-life, and delivered foam density. This page describes the chemistries we can specify; the numeric targets that actually work on a given line must come from bench and line trials.
A practical board foam mixes 'stable' foam (e.g. sodium lauryl sulfate) that carries load-bearing voids into the set core, with 'unstable' foam (e.g. sodium alpha-olefin sulfonate) that collapses partially into interconnected voids improving nail-pull. Bimodal foam architectures are described in the published patent literature — see for example US 8,470,461 (Saint-Gobain).
Foam volume, half-life and bubble size are the three primary controls. A foam that survives too little collapses before the knife; a foam that survives too long migrates and creates a soft top layer. Air-water ratio at the generator is the primary lever; surfactant chemistry sets the envelope.
- §US 8,470,461 — Low weight and density fire-resistant gypsum panel (Saint-Gobain) — USPTO
- §US 8,038,790 — Low dust joint compound / lightweight board patent family (USG) — USPTO