Polyurethane

BioPowder

Polyurethane (PU or PUR) is a synthetic polymer formed when polyols react with isocyanates.
It can be engineered as foams, elastomers, coatings, sealants, and adhesives.
Thanks to tunable chemistry, PU delivers flexibility, toughness, and resilience across industries.

What are polyurethane systems?

PU systems are two-component formulations that cure into polyurethane.
They combine a tailored polyol blend with an isocyanate to achieve the target profile.
Formulators dial in hardness, density, elasticity and cure speed.

In one line: A PU system is a reactive toolkit that becomes a durable polymer.

How does Polyurethane work?

Polyurethane has two components

Component A - Polyol side

Polyol or polyol mix
Catalysts and chain extenders
Additives for wetting, defoaming, UV, colour

Component B - Isocyanate side

MDI, TDI, HDI, IPDI or prepolymer
Monomer content controls reactivity and emissions

On mixing, polyaddition forms urethane bonds and networks cross-link to create thermoset PU, while with specific chemistry TPU remains re-meltable. Processing paths include cast, spray, foam-in-place and reaction injection moulding; cure can occur at room temperature or with heat; delivery formats span solvent-borne, water-borne, 100 percent solids and powder.

Why is polyurethane so versatile?

Segmented structure

Soft segments - flexibility and damping
Hard segments - strength and chemical hold

Fine control knobs

Polyether vs polyester polyols
Aliphatic vs aromatic isocyanates
Filler package, particle size, and surface energy

The outcome ranges from soft foams to high-modulus elastomers, and from high-gloss clears to deep-matte textures.

Where are PU systems used?

Coatings

In coatings, polyurethane systems are used on floors, machinery, automotive clear coats, and architectural paints, delivering strong UV stability alongside excellent abrasion and chemical resistance.

Foams

In foams, flexible grades serve furniture, automotive seating and bedding, while rigid grades underpin insulation boards, spray foam and appliances

Elastomers

In elastomers, polyurethane is used for wheels, rollers, gaskets, bushings and shoe soles, valued for its high tear resistance, strong load-bearing capacity and reliable rebound.

Adhesives and sealants

In adhesives and sealants, polyurethane enables structural bonding for building joints, footwear and woodworking, reliably joining diverse substrates while maintaining lasting flexibility.

PU coatings - what should specifiers look for?

Performance levers

Aliphatic systems for outdoor UV stability
Aromatic systems for heavy-duty interiors
Water-borne for low VOC and odour
High-solids for fast return to service

Finish control

Gloss 80 to full matte below 10
Slip tuning for R9 to R13 floor classes
Textures from silky to micro-grit

Typical tests include Taber abrasion, cross-cut adhesion and MEK double rubs, complemented by QUV weathering, chemical spot testing and skid resistance measurements in both wet and dry conditions.

PU foams

PU foams come in two main forms. Flexible foam features open cells and low density, providing comfort, acoustic damping and energy absorption—hence its use in seating, mattresses and packaging. Rigid foam has closed cells and a high insulation value, making it ideal for panels, cavity fills and cold chain appliances, with excellent strength-to-weight and thermal efficiency.

How does Polyurethane compare to other polymers?

PU vs epoxy

PU is more flexible and impact-tolerant
Epoxy is stiffer and brittle but great for high-strength bonds

PU vs PVC

PU offers better abrasion resistance and elasticity
PVC is rigid, low cost, and easier to weld

PU vs PP

PU excels in adhesion and damping
PP leads on chemical inertness and cost per kg

Can polyurethane be bio-based and low-impact?

Modern formulations increase bio-content and reduce CO2 without sacrificing performance. Pathways include bio-based polyols from plant and lignin streams, bio-fillers and texturing agents to lower polymer demand, water-borne dispersions and high-solids technologies to cut VOCs, and non-isocyanate PU for specific niches. On compliance, prioritise REACH, mandated isocyanate training and microplastic restrictions, and substantiate gains with Ecolabels and LCA evidence.

Typical KPIs for engineering and QA

Shore hardness, elongation, tensile, tear
Taber abrasion and falling sand wear
Adhesion after water and chemical spot tests
Gloss, haze, slip angle, friction coefficient
Density, solids, viscosity, pot life

BioPowder Additives for PU systems

With Olea FP—a plant-based, microplastic-free particle range—BioPowder provides multifunctional fillers that act as reinforcers, texturing and matting agents. Our Application Lab offers a 360 degree approach with guide formulations for PU and epoxy, engineered for elevated bio-content and a reduced footprint, and always practical, scalable and commercially viable. Typical benefits include lower density and weight savings versus mineral fillers, precise slip control with premium haptics in topcoats, and stable viscosity with clean dispersion in both water-borne and 2K PU.

FAQ - common queries about polyurethane

Is polyurethane a good or bad material?

Polyurethane is a high-performance material when correctly specified and processed. It offers durability, abrasion resistance, and strong adhesion. Concerns centre on isocyanate handling and end-of-life. Modern PU with bio-content and low VOC addresses many impacts.

Is polyurethane a plastic?

Yes. Polyurethane is a plastic in the wider polymer family. It exists as thermoset PU and as TPU, which is thermoplastic. Thermoset PU cannot be remelted after cure, TPU can be processed by heat.

What is polyurethane used for?

PU is used in coatings, foams, elastomers, adhesives, and sealants. Applications span floors, furniture, vehicles, appliances, and composites. Designers choose PU for its wear resistance, chemical durability, and tunable feel.

Glossary