PUR integral skin foams

Molds for PUR Integral Skin Foams (Self-Skinning Foams)... 

Flat parts with sufficient draft angle on the side do not require additional demolding aids. Flexible and semirigid integral skin foam parts can be ejected using compressed air. Rigid PUR integral skin foam products are ejected with mechanically or... 

Molds for flexible, PUR integral skin foams are required in the production of motor cycle seats, sun visors, and simple seat upholstery. These large molds usually consist of two parts. For suitable venting, molds for annular headrests require auxiliary parting planes that can be mounted with hinges on one of the mold halves. 

In-mould coating should be mentioned here for completeness. This technique is widely used for integral skin foam components in PUR, principally in the passenger compartment. It is also used to prime SMC parts, as an aid to producing a Class A finish on the topcoat. The RTM methacrylic resin panels of the Alfa Romeo SZ were in-mould coated to a Class A finish. As this was a specialist vehicle and no other painted panels were involved, the usual problems of reduced production rate and poor colour matching did not apply. 

Integral skin PUR foams are made by injecting the reactants into a closed (vented) or open mold. Reaction under fliese conditions produces a foam with a high-density outside skin layer and a soft foam interior. Common products such as steering wheels, footwear components, and computer housings generally employ integral skin PUR foams. 

Elastofoam Soft integral-skin PUR foam BASE Plastics... 

Traditionally the steering wheel has comprised a metal skeleton covered in plastic. For some 40 years the coating was cellulose acetate butyrate (CAB) hard, scratch resistant - and slippery in warm weather. Increasing safety awareness led to the dished hub, and to over-moulding in PP and PVC. More recently, in meeting the requirements of ECE 21 and FMVSS 203, improved performance opposite head and body impact requirements has been achieved by the use of integral-skinned PUR foam for wheel covers and hub padding (Fig. 4.17). 

Bonded sandwich structures are vital in aircraft design as they enable significant weight reduction without the loss of stiffness and strength. A sandwich panel comprises metallic or synthetic surface skins integrally bonded to a central core. In some instances, this core is balsa wood or, because of objections to using natural products in structural components, a foamed plastic. Typical examples of the latter are foams of polyvinyl chloride, phenolic, and polyurethane (PUR). 

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