In the manufacturing of flexible polyurethane (PU) foams, performance does not depend only on the polyol-isocyanate base. A technical factor that impacts the final quality of the foam is the correct use of silicones as stabilizing additives. Especially in the furniture sector, the importance of proper use in process control stands out.
Whether for soft foams or high-hardness foams, choosing the appropriate silicone ensures uniformity, stability, and durability. In this article, we explain how this works in practice — including tips for continuous production (slabstock) or molded foam.
What are silicones for flexible PU foams?
Silicones are cell-stabilizing agents used in flexible foam formulations. Their main function is to control the formation, expansion, and regularity of foam cells during the PU reaction, ensuring that the material reaches the expected performance.
In practice, they act in:
- Prevention of foam collapse after expansion
- Control of cell size and distribution (cellular structure)
- Direct influence on air passage, hardness, and foam appearance
Silicones for different densities: what should be considered?
| Foam Density (kg/m³) | Common Furniture Application | Silicone Characteristics |
| 10 to 16 | Cushions, pillow tops, soft backrests | Silicone with high stability favoring open cell structure |
| 17 to 23 | Seats, balanced upholstery | Moderate stabilization, preventing collapse while maintaining breathability |
| 24 ormais | Firm seats, structural foams | Silicone with more closed-cell action and lower active density |
Density directly influences the level of comfort and support performance of the foam. Silicone plays a fundamental role in stabilizing the cellular structure, ensuring the maintenance of these properties over time.
Continuous vs. molded process: how silicone behaves
In addition to density, it is essential to consider the type of manufacturing process.
Silicones for slabstock foams (continuous process)
- Formulations requiring high thermal resistance and stability during long production runs
- Must guarantee cellular stability throughout block growth, minimizing the risk of structural collapse
- Ideal for large-scale production of sheets, blocks, and laminated foams
Silicones for molded foams (injection)
- Require adequate control of flow and spreading inside the mold, ensuring uniform cavity filling;
- Prevent the formation of bubbles and surface defects;
- Typical applications: anatomical cushions, injected seats, armrests.
Amino additives: silicones compatible with your systems
At Amino, we not only develop customized PU systems — we also provide a complete line of additives, including silicones optimized for:
- Low, medium, or high densities
- TDI-based or MDI-based formulations
- Production in molds or in continuous and discontinuous blocks
Our silicones are present in Comfort lines, viscoelastic foams, HR foams, and molded systems, ensuring:
- Process stability
- Low rejection rate
- Controlled cellular structure
Why does this matter for the furniture sector?
A poorly adjusted silicone compromises:
- Comfort performance due to excessively open or excessively closed cell structure
- Upholstery durability, with premature collapse
- Aesthetic quality and surface finish due to irregularities in cell formation
- Production efficiency, reducing yield per mold or per block and increasing cost per piece
For manufacturers of foams intended for sofas, chairs, corporate furniture, pillow tops, and upholstered furniture, the correct silicone selection is a critical factor to ensure quality standardization, process stability, and the technical and economic competitiveness of the product.
The definition of the ideal stabilizing silicone for polyurethane foams goes beyond simple reaction stability, being decisive for the structural quality of the upholstery, the consumer’s perception of comfort, and the effective cost per produced piece.
Amino offers full technical support to identify the most suitable additive for your process and density. With expertise in flexible systems and additives, we deliver solutions that balance performance, comfort, and productivity.
Looking for:
- Silicone for polyurethane foam?
- Stabilizing additive for flexible foam?
- Silicone for slabstock or molded foam?
- Best additive for PU cell control?
- Silicones for the furniture industry?
You have found Amino. Talk to our technical team and optimize your formulation with the right silicones for each type of foam.
About Amino
Contact us and discover how Amino silicones can improve the performance of your furniture foams.