Global expertise in defoamers and foam control

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Whether your challenge deals with gypsum or plaster, PMC Ouvrie combines products that manage the physical properties of aqueous systems with technology and testing to provide defoamer solutions for a wide array of applications.

PMC OUVRIE defoamers DELFOAM™ & EROL™ improve the homogeneity of the finished products by reducing significantly foam air entrapment.

Gypsum-based products from wallboard and plaster to joint compounds and decorative moldings require precise density control and smooth surface finish. Foam generated during slurry preparation and application creates voids, reduces strength, and causes surface blemishes that impact both structural integrity and aesthetic quality. PMC Ouvrie's defoamers for gypsum and plaster deliver fast-acting foam control that enhances product consistency and manufacturing efficiency.

Specialized Solutions for Gypsum Systems

Our gypsum defoamer technology is formulated specifically for the unique chemistry of calcium sulfate systems. Gypsum slurries have a narrow working window between mixing and set time, which means foam control must be immediate and effective. Our defoamers work rapidly in high-solids, moderately acidic to neutral pH environments, eliminating entrained air without disrupting stucco formation or interfering with set retarders and accelerators.

Common Foam Challenges in Gypsum & Plaster Production

High-Speed Mixing Foam: Continuous gypsum board production and plaster mixing equipment operate at high speeds to maximize throughput. This vigorous agitation incorporates substantial air, creating foam that must be eliminated before the slurry reaches forming equipment or application surfaces. Even small amounts of residual foam can reduce board density below specifications.

Surfactant and Additive Interference: Modern gypsum formulations contain dispersants, water reducers, and surface-active additives that improve workability and reduce water demand. Unfortunately, these same ingredients stabilize foam bubbles, making them difficult to collapse. The challenge intensifies in lightweight gypsum products where intentional foaming agents are used—requiring precise differentiation between desired and undesired air content.

Surface Quality Issues: Foam that reaches the surface during board formation or plaster application creates pinholes, fish eyes, and crater defects. In decorative plaster and gypsum castings, these blemishes are unacceptable. For gypsum board, surface porosity affects paper bonding, joint compound adhesion, and paint finish quality.

Density Variability and Material Waste: Inconsistent foam levels from batch to batch cause density fluctuations that affect product weight, strength, and thermal properties. In board production, this variability can result in off-spec product. In bagged plaster, it reduces coverage rates and increases material costs for end users.

How PMC Ouvrie Defoamers Work in Gypsum Systems

Our defoamers for gypsum and plaster utilize fast-spreading silicone or mineral oil-based chemistries that rapidly destabilize foam interfaces. The active components migrate quickly to bubble surfaces, reducing surface tension and causing immediate collapse. Because gypsum systems have short working times (often just minutes), our formulations are designed for instant action upon addition to the mix.

The technology is optimized for:

• Gypsum wallboard and ceiling tile production
• Veneer plaster and multi-coat systems
• Joint compounds and texturing products
• Decorative and ornamental plaster castings
• Gypsum-based self-leveling underlayments
• Agricultural and industrial gypsum products

Unlike generic defoamers, our gypsum defoamer products are engineered to maintain effectiveness in the presence of starch, protein-based retarders, and other gypsum-specific additives without causing incompatibility or set time issues.

Performance Benefits

Optimal Density Control: Precise foam elimination ensures consistent product density, meeting manufacturing specifications batch after batch and reducing material waste from off-spec production.

Superior Surface Finish: Elimination of surface defects improves aesthetic quality in decorative applications and provides better substrate for paper bonding, paint adhesion, and finishing materials.

Enhanced Mechanical Properties: Reduced void content translates to improved compressive strength, impact resistance, and fastener holding power which is critical for structural gypsum board applications.

Increased Production Efficiency: Faster deaeration reduces mixing cycle times and minimizes line stoppages due to foam-related quality issues. Consistent slurry properties improve flow characteristics and forming equipment performance.

Improved Product Yield: Lower air content means more solid material per unit volume, increasing coverage rates for contractors and reducing shipping costs per functional unit.

Application Guidelines

Dosage Range: Typically 0.05-0.3% based on dry gypsum weight. Wallboard production generally requires lower dosages (0.05-0.15%), while heavily formulated specialty products may need higher levels.

Addition Point: Add to mix water before gypsum addition, or inject directly into the slurry stream immediately after the mixer. For bagged products, incorporate into the dry blend as a powder-absorbed defoamer or as a liquid additive for job-site addition.

Timing Considerations: Because gypsum sets rapidly, defoamer addition must occur early in the mixing sequence to allow adequate time for foam collapse before the slurry reaches forming equipment or application surfaces.

Compatibility Testing: Always evaluate new gypsum defoamer additions through lab-scale testing, particularly when modifying established formulations containing set modifiers, fiber reinforcement, or lightweight fillers.

Storage: Store in original containers in a cool, dry location. Protect liquid products from freezing. Agitate before use if settling has occurred.

Technical Support and Formulation Assistance

Gypsum systems vary significantly based on calcination method, additive packages, and production processes. PMC Ouvrie's technical specialists understand these nuances and can recommend the optimal defoamer chemistry for your specific application. We provide sample quantities for production trials and offer on-site technical support to help optimize dosing systems and integration points.

Looking to improve your gypsum or plaster formulation? Contact PMC Ouvrie today to discuss your foam control requirements and request product samples. Our team is ready to help you achieve consistent quality and enhanced production efficiency.