Polyurethane Foam FAQ - Building Envelope Solutions

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Polyurethane Foam FAQs

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Question: How does Polyurethane Foam actually work?
Answer: Urethanes are plastics that have gas-filled bubbles that make them light weight and a good insulating material.

Question: What is the difference between open-cell and closed-cell polyurethane foams? 
Answer: These two types of polyurethane foams have different R-values, permeability, strength, and costs. Click here for more information

Question: What is the difference between CFC, HCFC and HFC blowing agents in polyurethane foams?
Answer: These "Flouro-carbons" have different amounts of chlorine or are designed to prevent chlorine release into the atmosphere.

Question: Do urethanes "outgas" and are they toxic?
Answer: Urethanes are non-toxic and only require protection for our operators during installations, but the finished product is completely safe and has no formaldehydes.

Demelic had an independent testing laboratory test their HEATLOK product for off-gassing. They tested the product using the Underwriters Laboratory of Canada 705.1-98 test method. It is a pass/fail test, where the estimated indoor air concentration of volatile organic compounds is compared to the permissible concentrations. The permissible concentration is defined as 1% of the threshold limit value. The off-gassing for the HEATLOK product was under the permissible concentrations so they passed the test.

See the AMA article on toxicity for more information

Question: Are urethanes good for sound insulation?
Answer:  Open-cell urethanes are better than closed-cell foams for reducing air-borne sound.  Both are good at sealing holes that can let sound through wall or ceiling penetrations.  Structure-borne sound CANNOT be controlled with low-density infill materials such as foam.

Question:  What sort of paint should I use for covering polyurethane foam?
Answer:  Typically, spray-applied polyurethane foam is covered by interior or exterior wall coverings or ceiling or roofing details. That said, on occasion it is left exposed and the concern really is only that of ultra-violet light that will degrade the exposed foam over time. In exterior applications, a paint will not suffice, rather a protective coating should be used. The Spray Polyurethane Foam Alliance provides an excellent resource for selecting the appropriate coating for your application, and we recommend that you visit their website for this information.

Question: I've been thinking that I can specify in our air barrier specification - products section, that foam used for the "Polyurethane Foam Caulking" have a higher set temperature and/or density to preclude the use of other off-the-shelf types of polyurethane foams.  I think this would be good for quality control.

Answer:  There are four types of "polyurethane" field-processed materials that could be involved in creating a complete air barrier system - I'll do my best to summarize the materials and their typical uses. 

1. Polyurethane caulking: this is a sealant, but is not a foamed product, comes in a tube for use with a caulking gun, and would be used for small cracks, including the seams of exterior sheathing as an alternate to Tyvek.  Polyurethane caulk stays resilient and adheres to most substrates.  It is frequently also used s an adhesive.
2. Single-component polyurethane foam sealant: this is typically used in small quantities for sealing cracks too large for caulking, window and door rough openings, pipe and wiring penetrations, etc.  This comes in expanding and low-expansion formulas and is very controllable which makes it attractive for this type of air- sealing work.  This is a relatively low-density product that has a low R-value and is permeable.  It comes in disposable aerosol cans or in disposable cylinders that screw on to a reusable portable gun.  It costs between $8 and $12 per pound (not including the cost of the reusable gun).  (Examples: Pur-Fill, Todol, Zero-Draft).
3. Two-component polyurethane foam insulation/sealant in "portable" or "disposable" kit systems.  This type of foam comes complete with a set of plastic hoses and a gun for the professional or the do-it-yourselfer.  These kits are used in remote locations or for small projects where full-scale equipment is not cost-effective and can be used for air sealing or insulation.  Density and closed-cell content (less permeable, more R-value) are higher than the single-component foam; therefore, it is getting closer to the physical properties of a "real" machine-processed polyurethane.  Again, the cost of the material is relatively high ranging from $5 to $10 per pound.  At this level of material use, the OSHA requirements for supplied-air equipment kick in. (Examples: Instafoam Froth Paks, Handi Foam, Zero-Draft). Note: We have tried a number of single-component "portable" or "disposable" kit systems over the past 20 years.  None of them has ever been approved for use by our crews after in-house testing. They didn?t process correctly, didn?t ever set up, etc.
4. Spray-applied polyurethane foam (SPF) and injected polyurethane foam insulation / sealant systems are materials processed through high-tech permanent equipment. Materials can be processed in a variety of densities at much higher rates than with any type of portable equipment discussed above. Raw materials costs range from $1.30 to $2.20 per pound and have high R-values, low permeability, and are stronger than lower density products. Open-cell urethanes like Icynene can only be processed through full-scale equipment. (Examples: Icynene, Heatlok, SUPERGREEN FOAM)

Now to address the temperatures. The bottom line is that it depends on the brand and foam system.  Most manufacturers of machine processed foam systems have hot and cold weather versions of their products.  The retail products (cans and kits) are usually more forgiving as they are designed to be simple, but they don't have to do much except make a seal.  Dimensional stability, aged R-value, etc. are less important in lower density sealants than for serious insulation / air and vapor barrier materials. 

1. Caulking (tubes): All of our stock is on the road with the trucks, but the other types (latex, silicone, hybrids, etc.) all say above 40 degrees F.
2. Foam sealants (cans): Pur fill 1G says can must be 60 to 80, but doesn't give a substrate, ambient, or curing temperature. There is reportedly a new product on the market called Zero Draft. Its product data sheet indicates that it can be installed down to ?4 degrees F. We have not tested this material yet in the field.
3. Portable units (kits): Product data related to processing temperatures is scarce, but our supplier says he recommends 45 degrees F as the lower limit for this and the Pur fill products he distributes. The published service temperature range for the Insta-foam kits is -47 to 176 F. The Zero Draft products may be available in a two-component kit form as well.
4. Machine-Processed Systems: At the "big dig" we used foam that could be sprayed on ice and snow (down to say 10 degrees F) and we do steam pipes (up to 250 degrees). Most normal foam insulation systems range from 20 to 120 in the product data sheets. Material storage, processing, substrate, ambient, curing, and service temperatures and durations vary significantly from product to product. SUPERGREEN FOAM has a lower limit for processing of 60 degrees F, but installation techniques can stretch the limits a little (pass thickness, etc.). Icynene claims a much colder processing ambient or substrate temperature where closed-cell foam is not required. Published service temperatures for all of the urethanes we use are from -40 to 280 degrees F. 

In the chemical and manufacturing world, the terms polyurethane and urethane are often used interchangeably, sparking confusion among buyers, engineers, and industry professionals. Is there truly a polyurethane vs urethane distinction, or is it a myth perpetuated by jargon? What roles do urethane coatings play, and how does the difference between urethane and polyurethane impact product selection? 

This blog provides U.S. buyers with a clear, engaging roadmap to unravel this debate, exploring the chemistry, applications, and practical considerations

Understanding Polyurethane and Urethane

Polyurethane and urethane both stem from the same chemical family, rooted in the reaction of isocyanates with polyols to form urethane linkages (–NH–COO–). The polyurethane vs urethane debate often arises from terminology rather than substance. Polyurethane is a polymer with multiple urethane groups, used in foams, coatings, and adhesives. Urethane, technically a single linkage or monomer, is loosely applied to similar materials, especially urethane coatings. The difference between urethane and polyurethane is more about context than chemistry, but nuances in formulation and application matter. Let’s debunk the myth and clarify their roles for U.S. buyers.

Also Read: From Raw Materials to Final Product: How Is Polyurethane Made for Industrial Coatings

Debunking the Myth: Polyurethane vs. Urethane

The polyurethane vs urethane question boils down to terminology, not a fundamental chemical divide. Here’s the truth:

Chemical Composition

• Urethane: Refers to the chemical linkage formed when an isocyanate (e.g., MDI) reacts with a hydroxyl group (e.g., polyol). It’s a building block, not a standalone material.
• Polyurethane: A polymer with multiple urethane linkages, often incorporating polyols, isocyanates, and additives like catalysts or surfactants. It’s the final product, like foam or coating.

Reality: Urethane is a component of polyurethane. Calling a product “urethane” is shorthand for polyurethane, especially in coatings or elastomers.

Terminology in Industry

• Urethane: Commonly used for single-component or simpler systems, like urethane coatings for floors or wood. It’s a marketing term emphasizing durability.
• Polyurethane: Applied to complex, multi-component systems, like flexible foams in mattresses or rigid foams in insulation.

Reality: The difference between urethane and polyurethane is semantic, driven by industry habit or branding, not distinct chemistry.

Practical Implications

• Interchangeability: Most “urethane” products (e.g., urethane coatings) are polyurethanes, formulated with specific properties (e.g., UV resistance).
• Buyer Confusion: Mislabeling can lead to selecting the wrong product (e.g., choosing a “urethane” coating unsuitable for outdoor use).

Reality: The polyurethane vs urethane distinction is negligible; focus on product specs, not labels.

Why It Matters: Understanding this myth ensures buyers prioritize performance over terminology when sourcing for applications like urethane coatings.

Key Applications of Polyurethane/Urethane

The difference between urethane and polyurethane fades in practice, as both terms describe similar products. Below are key applications, with a focus on urethane coatings:

Urethane Coatings

Urethane coatings, typically polyurethanes, protect surfaces with durability and aesthetics. What do they do? Resist abrasion, chemicals, and UV light. Where are they used? Wood floors, automotive finishes, and industrial equipment (e.g., 50-100 µm thickness). Formulations include water-based or solvent-based systems, with additives for gloss or hardness. Sustainable options use bio-based polyols, reducing VOCs (<50 g/L).

Link to Tianjin Ruifeng

Why It Works: Urethane coatings highlight the versatility of polyurethane in high-performance finishes.

Flexible Foams

Polyurethane foams cushion furniture, mattresses, and car seats. What do they do? Provide comfort and resilience (e.g., 20-50 kg/m³ density). Where are they used? Consumer goods and automotive interiors. Green practices incorporate recycled polyols or low-emission catalysts.

Why It Works: This application showcases polyurethane’s adaptability, often labeled as “urethane” foam.

Rigid Foams

Polyurethane rigid foams insulate buildings, refrigerators, and pipelines. What do they do? Offer high thermal resistance (R-value 5-7 per inch). Where are they used? Construction and appliances. Sustainable formulations use HFO blowing agents, minimizing ozone depletion.

Why It Works: Rigid foams demonstrate polyurethane’s energy-saving potential.

Adhesives and Sealants

Polyurethane adhesives bond metals, plastics, and wood, while sealants fill gaps in construction. What do they do? Provide strong, flexible bonds (e.g., tensile strength >2 MPa). Where are they used? Automotive assembly and building facades. Eco-friendly options reduce isocyanate emissions (<0.1 ppm).

Why It Works: These products, sometimes called “urethane” adhesives, excel in durability.

Elastomers

Polyurethane elastomers form tough, flexible components like wheels, belts, or gaskets. What do they do? Resist wear and impact (e.g., Shore A 80-90 hardness). Where are they used? Industrial machinery and medical devices. Sustainable systems use bio-based isocyanates.

Why It Works: Elastomers blur the polyurethane vs urethane line, delivering robust performance.

Also Read: How Do Chemicals in Industrial Coatings Improve Corrosion Resistance in Harsh Environments?

Comparing Properties: Polyurethane vs. Urethane Products

While the difference between urethane and polyurethane is minimal, product formulations vary. Here’s a comparison for urethane coatings and other forms:

Why It Matters: Buyers should focus on specs (e.g., VOCs <50 g/L for coatings) rather than the polyurethane vs urethane label.

Sourcing Considerations for U.S. Buyers

To purchase polyurethane or urethane products, U.S. buyers must navigate the polyurethane vs urethane confusion:

Clarify Product Needs

• Specify application (e.g., urethane coating for floors vs. foam for insulation).
• Request technical data sheets (TDS) for properties (e.g., hardness, cure time).

Verify Quality

• Check purity of raw materials (e.g., <0.1% free isocyanate in coatings).
• Ensure compliance with ASTM (e.g., D for coating abrasion) or FDA for medical uses.

Prioritize Sustainability

• Source bio-based or low-VOC formulations (e.g., <50 g/L for urethane coatings).
• Partner with suppliers like Elchemy for REACH-compliant products.

Manage Costs

• Budget for $2,000-$7,000/ton based on form (e.g., coatings vs. elastomers).
• Negotiate contracts to hedge raw material volatility (e.g., MDI price swings).

Ensure Regulatory Compliance

• Verify SDS for OSHA handling (e.g., <0.1 ppm isocyanate exposure).
• Confirm EPA compliance for VOCs or blowing agents in foams.

Optimize Logistics

• Use UN-approved containers (e.g., 200 L drums for coatings) per DOT rules.
• Source from Elchemy for trackable, tariff-compliant delivery.

Why It Works: These steps ensure buyers get the right product, regardless of difference between urethane and polyurethane.

Handling and Storage Guidelines

Safe management is critical for polyurethane/urethane products:

• Handling: Wear nitrile gloves, goggles, and respirators (<0.1 ppm isocyanate per OSHA). Use in ventilated areas for coatings or adhesives.
• Storage: Store at 15-25°C in sealed drums (e.g., HDPE for coatings) to prevent moisture curing. Keep foams dry (<50% humidity).
• Spill Response: Absorb liquid spills (e.g., coatings) with sand, dispose as hazardous waste per EPA. Ventilate for isocyanate vapors.
• Segregation: Keep away from water or amines to avoid reactions (e.g., CO₂ release in foams).

Why It Works: Proper handling ensures safety and quality for urethane coatings and other forms.

Green Chemistry in Polyurethane/Urethane

Sustainable practices align with polyurethane vs urethane applications:

• Bio-Based Materials: Use sugarcane-derived polyols for coatings or foams, cutting CO₂ emissions by 20%.
• Low-VOC Formulations: Water-based urethane coatings reduce emissions (<50 g/L).
• Recycling: Recover >70% polyurethane from mattresses or insulation for reuse.
• Emission Control: Catalysts minimize isocyanate release (<0.1 ppm) in production.
• HFO Blowing Agents: Replace HFCs in rigid foams, reducing ozone impact.

Why It Matters: Green chemistry supports eco-friendly urethane coatings and compliance with EPA/REACH.

How Elchemy Supports Buyers

Elchemy empowers U.S. buyers navigating polyurethane vs urethane:

• High-Purity Supply: Polyurethane coatings, foams, and adhesives with TDS and COAs.
• Regulatory Compliance: SDS for OSHA, EPA, and REACH audits.
• Custom Formulations: Low-VOC urethane coatings or bio-based foams for specific needs.
• Technical Expertise: Guidance on specs (e.g., Shore A 80 for elastomers) and applications.
• Sustainable Sourcing: Bio-based polyols and low-emission production.
• Logistics: UN-compliant delivery, mitigating tariff risks (e.g., 10% on Chinese MDI).

Elchemy clarifies procurement, debunking the difference between urethane and polyurethane.

Practical Tips for U.S. Buyers

Optimize polyurethane vs urethane sourcing with these steps:

1. Define Application: Choose urethane coatings for floors or foams for insulation.
2. Check Specs: Verify TDS for properties (e.g., <50 g/L VOCs, >2 MPa adhesive strength).
3. Source from Elchemy: Ensure compliant, sustainable supply with SDS.
4. Test Quality: Confirm purity and performance (e.g., ASTM D for coatings).
5. Go Green: Select bio-based or low-emission products for ESG goals.
6. Train Staff: Educate on SDS, PPE, and spill response for safety.
7. Budget Wisely: Plan for $2,000-$7,000/ton, factoring raw material costs.

Real-World Examples

Imagine these showcasing polyurethane vs urethane clarity:

• A U.S. flooring contractor using urethane coating (polyurethane) for durability, sourced from Elchemy with <50 g/L VOCs.
• A furniture maker selecting flexible polyurethane foam for mattresses, recycling 70% material.
• An auto manufacturer bonding parts with polyurethane adhesive, ensuring <0.1 ppm isocyanate exposure.
• A construction firm insulating buildings with rigid polyurethane foam, using HFO agents.
• A machinery supplier crafting polyurethane elastomers for belts, leveraging bio-based polyols.

These highlight practical applications, supported by Elchemy’s supply.

Want more information on polyurethane raw material manufacturer? Feel free to contact us.

Is There a Difference Between Polyurethane and Urethane?