A Global Approach to Polyurethane Resins for Composites

A Global Approach to Polyurethane Resins for Composites Polyurethane chemistry offers a wide range of options Mechanical properties Environmental resistance Processing characteristics Custom formulation Price Nautilus provides the opportunity to explore more of the available options than any other resin supplier

Mechanical Property Flexibility: Hardness Rubber Polyurethanes Plastics Durometer A Durometer D Rockwell R Rubber Band Tire Tread Shoe Heel Fluorocarbons PolypropylenePolystyrene Nylons AcrylicsPhenolics

Mechanical Property Flexibility: Elongation to Failure 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 200% Elongation to Break (Tensile) Polyurethanes Epoxies Polyesters

Mechanical Property Flexibility: Impact Resistance Izod Impact, Notched (J/cm) Polyurethanes Epoxies Poly- esters

Processing Flexibility Two-Component Systems Highly reactive (Resin injection) Moisture sensitive (tendency to foam) Color limitations (base resin is yellow) Inexpensive ($1.20 to $2.25/lb) Prepolymer Systems Controlled reactivity (‘One-pack’ technology) Moisture insensitivity (relatively) Clear/white Higher Cost ($1.90/lb and up)

Development & Sourcing Two-Component Systems Bayer Polyurethanes Huntsman Polyurethanes Custom formulations The technology leaders in polyurethane chemistry Worldwide manufacturing and sourcing Broad catalog of existing formulations Prepolymer Systems Chemtura Corporation (formerly Crompton/Uniroyal Chemical) A leader in polyurethane products & applications Several unique technologies with value for composites Aggressive R&D and tech support teams Custom formulations

Two-Component System Chemistry MDI (provides “NCO” Groups) + Polyol Blend (provides “OH” Groups) = Polyurethane H H C C C C C C H H O H C C H H H H H O H C C H H H H H CN O CN O C C O H H H H H H C C O H H H H H H H H C C C C C C H H CN O CN O

Two-Component Systems: Mechanical Properties More than 10 custom formulations developed and tested to date Processing flexibility: both filament winding and pultrusion Typical composite mechanical properties: PropertyMetricImperial Glass Content 70% 70% Tensile Strength (ASTM D638)780MPa 110ksi Tensile Modulus (ASTM D638)48.0GPa 6900ksi Flexural Strength (ASTM D790)1.6GPa 230ksi Flexural Modulus (ASTM D790)40GPa 5800ksi Compressive Strength (ASTM D695)450MPa 65ksi Compressive Modulus (ASTM D695)19GPa2700ksi Interlaminar Shear Strength (ASTM D732) 84MPa 12.0ksi Izod Impact (ASTM D4812)7.2N-m/mm135 ft-lb/in Barcol Hardness (ASTM D2583) Charpy Impact (ASTM D256)17.0 N-m 13 ft-lb Specific Gravity (ASTM D792)1.3 kg/l 7.56 lb/gal Heat Deflection Temp (ASTM 66 psi 200°C 264 psi 200°C 392°F

Two-Component Systems: Production Setup for Pultrusion Die Heat Zone Cooling Zone Injector Box Static Mixing Tube Resin Mixing Box Metering Pump Roving Card Supply Pump & Agitator Desiccant Air Filter Supply Pump Vent Hood

Two-Component Systems: Production Setup for Filament Winding Disposable Static Mixing Tube Impingement Mixer Metering Pump Low-Volume Resin Bath 150°F Cure 30 min Room- Temp Post-cure 24 hrs Desiccant Air Filters

Two Component Systems: EPA & OSHA Provisions Exposure Limits are Very Low (TLV = 5 ppb; PEL = 20ppb) During Normal Operations With NO Ventilation, it is Difficult to Reach the TLV Some Unusual Situations Could Cause a Limit Exceedence A Simple Vent System Will Prevent Limit Exceedences Without Causing Any Environmental Problems Ref: Paper Presented by Dr. Ravi Joshi, Huntsman Polyurethanes, CFA 2001 MDI is NOT a Listed HAP. Mass Balance & Control of OSHA Issues Required ONLY.

How Prepolymer Systems Differ from Two-Component Systems Polyol + IsocyanatePrepolymer Heat Opens up choices of isocyanates that can be used (MDI, TDI, PPDI, or Aliphatics) VERY little free isocyanate gets to the customer Prepolymer + CurativePolyurethane Energy Faster reaction that requires little energy input Wide selection of curatives allows direct control of reactivity and pot life …at Chemtura …at Customer Advantages:

Typical Prepolymer System Chemistry Polyurethane Prepolymer Urethane Linkages NCO Group NCO Group H H C C C C C C H H H H C C C C C C H H CN O CN O O H C C H H H H O H C C H H H H CN O CN O O H C C H H H H O H C C H H H H CN O CN O C C C C C C H H N H H C C C C C C C H H N Curative (MDA) C C C C C C H H H C C C C C C C H O O N N H H C C C C C C H H H H C C C C C C H H CN O CN O O H C C H H H H O H C C H H H H CN O CN O O H C C H H H H O H C C H H H H CN CN H H

Low-Free-Monomer Prepolymers Offer Both Safety and Performance Benefits Contain less than 0.1% free isocyanate monomer Dramatically reduces in-plant health & safety concerns Eliminates the need for any special ventilation Tightly controlled molecular weight Reduces viscosity to levels comparable to epoxies Enhances structural properties of final polymer Reduces structural property variation % Molecular Wt. Free Monomer High MW (Viscosity) % Molecular Wt.

Physical Properties of Some Off-the-Shelf Low-Free-Monomer Prepolymers The Exceptional Elongation of these Materials Opens up New Applications and New Markets for Composites Manufacturers LF650DLF700DLF701DLF750DLF751D Hardness (Shore D) Elongation-to-Break (%) Modulus to 100% Elongation (psi) Modulus to 300% Elongation (psi) Brittleness Temp (°F) -94

Caytur 31 Curative Technology Makes Use of MDA Safe and Practical C C C C C C H H N H H C C C C C C C H H N C C C C C C H H N H H C C C C C C C H H N C C C C C C H H N H H C C C C C C C H H N Na Cl 3 MDA Curatives Sodium Chloride Curative MDA monomer is bound to a salt molecule at room temp Heat releases the MDA monomer to react with prepolymer ‘Snap-cure’ occurs when MDA monomer is released Release temperature is controllable from °C with an inexpensive catalyst that also serves as a mold release

Prepolymer Systems: Production Setup for Filament Winding “Shop Air” Fiber Cures in as little as 10 – 30 seconds exposure to infrared energy

OSHA/EPA Considerations with Prepolymer Systems Production setup – conventional open-bath No special ventilation required because of low-free- monomer prepolymers – standard factory ventilation is satisfactory Caytur 31 curative falls under EPA regulation 29 CFR because of MDA content – Initial monitoring during demonstration usually results in exemption from the most demanding requirements of the regulation – Periodic confirmation is prudent – Primary route of exposure is dermal, so good cleanliness practices eliminate the hazard

Summary Bayer/Huntsman/custom two- component systems are directly and immediately applicable to many composites applications Chemtura prepolymer systems open up whole new markets and applications for exploration