Polyurethane Foam Formulation Articles & Guides
PolymersIQ articles form the main polyurethane foam formulation knowledge hub for PU foam formulation, raw materials, foam chemistry, process control, QC and troubleshooting.
Use this technical article library to explore hydroxyl value, equivalent weight, isocyanate index, polyol and isocyanate behavior, raw material variation, density control, compression set and production defect diagnosis.
Latest polyurethane foam articles
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TDI 80/20 vs TDI 65/35 in Polyurethane Foam Formulation
— Formulation
Compare TDI 80/20 and TDI 65/35 in polyurethane foam formulation, including same %NCO, different isomer ratios, reactivity, timing, and switching risks.
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How TDI 80/20 and TDI 65/35 Affect Polyurethane Foam Cream Time
— Process Control
Learn how TDI 80/20 and TDI 65/35 affect polyurethane foam cream time, gel time, rise profile, gel/rise gap, and foam stability.
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TDI 80/20 vs TDI 65/35: 3 Switching Mistakes That Damage Foam
— Foam Defects
Learn how switching between TDI 80/20 and TDI 65/35 can change catalyst balance, gel/rise gap, collapse risk, density, and slabstock foam quality.
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Polyurethane Foam Types: Uses, Selection and Failures
— Raw Materials
Compare nine polyurethane foam types, from flexible and HR foam to rigid PU, PIR, spray, semi-rigid, integral skin, and rebonded foam, with uses and failure limits.
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Flexible Slabstock vs Molded vs HR Foam Selection Guide
— Raw Materials
Compare slabstock, molded, and HR flexible PU foam by cost, shape precision, recovery, compression set, and failure risk.
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Rigid PU Foam vs PIR vs Spray Foam: Insulation Guide
— Raw Materials
Compare rigid PU foam, PIR foam, and spray foam by insulation performance, fire behavior, vapor control, applications, and selection limits.
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Semi-Rigid, Integral Skin & Rebonded PU Foam Types
— Raw Materials
Compare semi-rigid, integral skin, and rebonded PU foam by function, applications, selection limits, and common failure risks.
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How to Choose the Right Polyurethane Foam Type by Failure Mode
— Quality Control
Choose the right polyurethane foam type by failure mode—thermal, fire, compression set, impact, moisture, shape, variation, and cost risks.
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Polyol and Isocyanate in PU Foam: How the Main Reactive Pair Builds the Network
— Formulation
Learn how polyol and isocyanate build the PU foam network through OHV, %NCO, equivalent weight, functionality, CoA values, and isocyanate index control.
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Water and Catalyst in PU Foam: Density Control vs Reaction Timing
— Formulation
Learn how water controls PU foam density, urea, exotherm, and index demand, while catalyst controls cream, gel, rise, and cure timing.
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Surfactant and Crosslinker in PU Foam: Cell Structure vs Network Strength
— Formulation
Learn how surfactant controls PU foam cell structure while crosslinker builds network strength, affects compression set, and changes isocyanate index demand.
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3 Polyether-to-Polyester Polyol Switching Mistakes
— Process Control
Learn the three polyether-to-polyester polyol switching mistakes that cause PU foam defects, viscosity problems, index drift, and hidden formula errors.
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When to Choose Polyether or Polyester Polyol in PU Foam
— Formulation
Learn how to choose polyether or polyester polyol by failure mode, moisture exposure, mechanical strength, processing limits, and total application risk.
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Polyether vs Polyester Polyols: Foam Formulator Guide
— Formulation
Compare polyether and polyester polyols by backbone chemistry, hydrolysis resistance, mechanical strength, viscosity, processing needs, and correct PU foam applications.
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5 Catalyst Adjustment Mistakes in PU Foam Production
— Formulation
Learn five common catalyst adjustment mistakes in PU foam production, including wrong amine selection, tin overuse, index drift, seasonal imbalance, and misdiagnosed foam defects.
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Gel Time vs Rise Time in PU Foam: Read the Balance
— Formulation
Introduction Gel time vs rise time PU foam analysis is one of the most important ways to understand reaction balance in polyurethane foam production. But these timing values are...
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Gelling vs Blowing Reaction in Polyurethane Foam
— Formulation
Introduction Gelling vs blowing reaction balance is one of the most important controls in polyurethane foam because it determines whether foam rise and polymer strength develop...
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The Dual Role of Water in PU Foam Formulation
— Formulation
Introduction The dual role of water in PU foam is one of the most important formulation controls in flexible polyurethane systems. Water is one of the smallest ingredients in a...
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What a PU Formulation Sheet Cannot Tell You
— Process Control
Introduction A polyurethane formulation sheet can tell you a lot. It can show component names, parts by weight, equivalent weights, reactive equivalents, weight percentages,...
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Why Changing One PU Foam Raw Material Changes Everything
— Raw Materials
Introduction PU foam raw material changes rarely affect only one property. A foam plant has a hardness drift. The engineer adjusts the catalyst. Hardness improves slightly, but...
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Reactive vs Non-Reactive Components in PU Foam
— Formulation
Introduction Reactive components in polyurethane foam are the raw materials that chemically enter the isocyanate index calculation. A polyurethane foam formula contains six...
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PU Foam Raw Materials: The Six Families Explained
— Formulation
Introduction PU foam raw materials are the foundation of every polyurethane foam formulation. Whether the final product is a soft mattress foam or a rigid insulation foam, the...
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How to Read a Polyurethane Formulation Sheet
— Formulation
Introduction A polyurethane formulation sheet looks like a recipe. Component names are listed in one column. Quantities are written in another. A target index may appear at the...
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Polyol Functionality, Crosslink Density & Compression Set
— Formulation
Introduction Compression set failures are not always process problems. They are often network architecture problems. A foam plant may adjust catalyst, increase crosslinker, raise...
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4 NCO Content Mistakes That Corrupt PU Foam Index
— Process Control
Introduction NCO content mistakes are dangerous because they do not always look like NCO content mistakes. They usually appear as ordinary foam quality problems. One batch is...
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TDS %NCO vs CoA %NCO: Use the Drum Value in PU Foam
— Formulation
Introduction Every drum of isocyanate that arrives at a foam plant can have a different %NCO value. Most plants still use the same number for all of them. That number usually...
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NCO Content in Isocyanate: What %NCO Means in PU Foam
— Formulation
Introduction NCO content is one of the most important raw material values in polyurethane foam formulation. It tells you how much reactive isocyanate functionality is available in...
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4 Water Adjustment Mistakes in PU Foam Production
— Process Control
Introduction Water is one of the most powerful variables in flexible polyurethane foam formulation. It is also one of the most misunderstood. Many foam plants treat water as a...
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How Water Level Effects PU Foam Properties
— Formulation
Introduction Water level is one of the most powerful variables in flexible polyurethane foam formulation. Most engineers understand its effect on density. Increase water — more...
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5 Equivalent Weight Mistakes in PU Foam Production
— Process Control
Introduction Equivalent weight mistakes are some of the hardest formulation problems to diagnose in polyurethane foam production. They rarely create an obvious machine failure....
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4 Polyol Functionality Mistakes in PU Foam Production
— Process Control
Introduction Compression set failures are often treated as process problems. The foam plant checks catalyst balance. The engineer raises the index. Crosslinker dosage is...
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Why Water Equivalent Weight Is 9 in Polyurethane Foam
— Formulation
Introduction The equivalent weight of water in polyurethane foam is 9, not 18. This is one of the most important rules in PU foam formulation — and one of the most damaging...
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Equivalent Weight in PU Foam: Calculation Guide
— Formulation
Introduction Equivalent weight is one of the most important calculation values in polyurethane foam formulation. It is also one of the most common sources of hidden formulation...
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5 Hydroxyl Value Mistakes That Create PU Foam Production Problems
— Process Control
Introduction Hydroxyl value mistakes are dangerous because they rarely look like hydroxyl value mistakes. They usually appear as ordinary foam production problems. The foam is...
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Why Polyol OHV Variation Causes PU Foam Quality Issues
— Process Control
Introduction Most foam quality problems are blamed on the machine. Sometimes the machine is not the problem. A foam plant may spend days adjusting catalyst levels, checking...
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Hydroxyl Value in Polyurethane Foam: What OHV Means and How to Calculate Equivalent Weight
— Formulation
Introduction Most polyurethane foam quality problems are blamed on the machine. The machine is not always the problem. In many foam plants, the real cause is sitting inside the...
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How Isocyanate Index Affects PU Foam Properties
— Formulation
Introduction The isocyanate index is not just a calculation number. It directly affects the physical behaviour of polyurethane foam. When the index changes, the foam does not only...
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5 Isocyanate Index Calculation Mistakes That Cause PU Foam Quality Problems
— Process Control
Introduction In polyurethane foam production, the isocyanate index is one of the most important control numbers in the formulation. It affects hardness, compression set,...
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Isocyanate Index Calculation Guide for PU Foam Engineers
— Formulation
A wrong isocyanate index can silently push foam out of spec. Learn the correct calculation, water correction rule, and a full worked example.
Important PolymersIQ pages
- Polyurethane Foam Resources & Tools
- Polyurethane Foam Uses by Industry
- Free PU Foam Calculators
- Equivalent Weight Calculator
- TDI Calculator
- Isocyanate Index Calculator
- Foam Density Calculator
- Polyol Blend Calculator
- Water Isocyanate Reaction Calculator
- Raw Material Cost Calculator
- PPHP Flowrate Calculator
- Polyurethane Foam Defects
- Blindness in PU Foam
- Shrinkage in Rigid PU Foam
- Splits & Cracks in Flexible Foam
- Polyurethane Foam Applications & Selection
- Consulting Services
- Polyurethane Foam Support Contact