What is the difference between foam and PU foam?

A foam is, at its simplest, a mix of gas bubbles trapped in a liquid or solid matrix—think of the frothy head on a beer or a soft bath sponge. Polyurethane (PU) foam, by contrast, is a specific family of foams created when polyols (liquids with multiple hydroxyl groups) react with diisocyanates, forming a network of urethane links and gas cells. This chemical distinction gives PU foam its hallmark combination of lightweight cushioning and tailorable performance, setting it apart from other foams used in everyday products.

What Makes Generic Foam “Foam”?

Foam, in general, refers to any material where gas pockets are dispersed within a continuous liquid or solid phase. Whether it’s the sudsy bubbles in a soap lather or the polymeric foam in packaging peanuts, the basic principle is the same: gas cells surrounded by thin films of liquid or solid. Foams can be open-cell (where cells interconnect and allow air or liquid to pass through) or closed-cell (where each gas pocket is sealed off), impacting properties like breathability and water resistance.

How PU Foam Is Chemically Unique

Polyurethane foam stands out because it’s formed by the polymerization of two distinct monomers: polyols and diisocyanates. When mixed—often with catalysts, surfactants, and blowing agents—these components react to form a viscoelastic network that traps CO₂ (from added water or other blowing agents) in an open-cell or closed-cell structure. By varying the ratio of polyol to isocyanate, the type of blowing agent, and the surfactants used, manufacturers can produce PU foams with densities from 10 kg/m³ (very soft) up to 250 kg/m³ (very firm) and tailor hardness, rebound, and thermal properties.

Key Performance Differences

Feature	Generic Foam	PU Foam
Composition	Any gas + liquid/solid	Polyol + Diisocyanate polymer network
Density Range	Wide, but often not engineered precisely	10–250 kg/m³, tightly controlled
Elasticity & Rebound	Varies; often low rebound	Tunable rebound (high in HR foams)
Durability	Can degrade quickly	Excellent lifespan with low compression set
Thermal & Acoustic	Basic insulation if closed-cell	Superior insulation with rigid grades
Applications	Firefighting foam, food froth, packaging	Insoles, seating, insulation, adhesives

Why Choose Yongjiu’s PU Foam Sheets?

Customizable Comfort & Support
- With densities from 50–90 kg/m³ for Memory Foam to 100–150 kg/m³ for Ortholite-type sheets, Yongjiu tailors each PU foam to match specific end-use requirements.
Consistent Quality
- Our ISO-certified production lines ensure each batch meets ASTM D3574 (density/compression set) and ASTM D2240 (hardness) standards.
Versatile Sheet Cutting
- We offer 2–50 mm thickness, rolls of 20 m or 40 m, and widths of 1.40/1.45/1.50 m, with no-joint precision cutting for seamless integration .
Eco-Forward Options
- Choose up to 15 % recycled content or bio-based polyol blends to meet green-manufacturing goals.
Clear B2B Terms
- FOB Xiamen (Incoterms 2020): We manage all China logistics, you handle export.
- Payment: 30 % T/T deposit, 70 % against B/L (large orders); 100 % T/T or cash (small orders).
- MOQ: 22.4 m³ (one 40 m × 1.4 m × 0.4 m roll); custom slicing available.
- Lead Time: 5–7 business days (standard); 7–10 days (custom) after sample approval & deposit.