Polyurethane Systems

In a polyurethane system, the isocyanate (component A) and polyol (usually a polyol blend) (component B) are supplied in a prepackaged formulation, or system. The system may also include color additive. The polyurethane system is ready to be processed into the polyurethane part. Polyurethane systems generally are supplied in traditional drums or in returnable intermediate bulk containers (IBCs). Some polyurethane systems are supplied in bulk via tank trucks.

The degree of rigidity usually defines a polyurethane system, placing it in one of two categories – rigid or elastomeric.

• A rigid polyurethane system generally has a higher flexural modulus and degree of hardness. This category of materials normally offers good thermal resistance, electrical properties, chemical resistance, and acoustical insulation. For example, rigid polyurethane foams are used to insulate residential and commercial buildings.

• An elastomeric polyurethane system is often found in applications requiring superior impact strength. Elastomeric polyurethane systems exhibit good toughness and dimensional stability throughout a wide temperature range and have excellent corrosion, abrasion, wear, and cut resistance. Elastomeric polyurethanes are used to make inline skate wheels, footwear soling and bushings and vibration pads for industrial machinery.

Within these two categories, there are three types of polyurethane systems:

• Foamed polyurethane systems – use a blowing agent to make parts with a higher-density skin and a lower-density, microcellular core in a sandwich-like composition. They are commonly referred to as foamed RIM. Applications for these materials include business machines, electronic and medical housings, automobile spoilers, skis, and other load-bearing applications.

• Solid polyurethane systems – do not use blowing agents, resulting in a homogeneous, rigid or elastomeric plastic. They are commonly referred to as reinforced RIM or RRIM. Applications for these materials include automotive, specialty transportation, construction, agriculture, and recreational industries.

• Structural composite polyurethane systems – are solid or foamed materials, molded in combination with long-fiber reinforcements, such as preformed glass fiber mat or chopped glass fibers, to improve the mechanical characteristics. These systems have extremely high stiffness and high impact strength because of the glass fiber reinforcement. They are commonly referred to as structural RIM or SRIM. Applications for these materials include automotive door panels, package shelves and load-bearing panels, and recreational equipment parts. These polyurethane systems are finding many new uses in the composites market.

BaySystems® Polyurethane Systems

Bayer offers a wide range of polyurethane systems in North America under the BaySystems® brand.