Low-Dust Joint Compound and Related Lightweight Board System
The patent family that reframed what a half-inch board weighs and forced a three-year industry catch-up.
- Assignee
- United States Gypsum (USG)
- Jurisdiction
- United States
- Filed
- 2008-12-23
- Published
- 2011-10-18
- Status
- Granted
Discloses a gypsum board with reduced core density achieved through an engineered air-void distribution coupled to a rebalanced migratory-starch system, providing the bond strength of a conventional board at significantly lower areal weight.
Before UltraLight, the half-inch standard board was ~1.6 lb/ft². The published family enabled ~1.2 lb/ft² without sacrificing nail-pull or fastener-head holding. Every major manufacturer has now released a competing lightweight SKU; the family teaches that the lever is process architecture, not a single magic surfactant.
- Claim 1
Bimodal air-void distribution: a fine, stable population in the 60–120 µm range and a coarser interconnected population in the 180–350 µm range.
- Claim 2
Migratory starch dosage scaled to the lower bleed-water volume of the lightened core to preserve paper bond.
- Claim 3
Kiln profile (implicit in dependent claims) lengthened in the flash zone and gentled in equalization to handle reduced thermal mass.
If you are trying to replicate at-spec performance without a license you cannot just push air content. The three legs — dispersant, foam pair, starch — must move together, and the kiln must be re-tuned. Plants that ignore the kiln half of the patent see paper-bond failures within two weeks of conversion.
- · USPTO Patent Full-Text Database, US 8,038,790 B2
- · USG public datasheets, Sheetrock Brand UltraLight