| 摘要 |
<p>TITLE: RESILIENT WATERPROOF MATERIAL A flexible waterproof or sealing material with good load bearing properties, low compressibility and good abrasion resistance is constituted by a porous polyurethane material having a density in the range 25-50 lb/ft3 impregnated with elastomeric material to an extent of 5-50% by weight of the polyurethane. The preferred polyurethane material is reconstituted polyurethane foam made by bonding together particles of comminuted polyurethane foam, preferably with a particle size not exceeding 4 mm, with a polyurethane binder. Materials made from pulverized foam with a particle size of less than 2 mm and moulded under pressure, which are not recognisably cellular although atill sufficiently porous for impregnation, are particularly valuable as starting materials. Preferred impregnants include rubbers, vinyl polymers and co-polymers, acrylic elastomers, butyl rubbers and especially carboxylated styrene-butadiene rubbers. The materials can be used wherever flexibility, sealing and wear resistance are required, for example in shoe components, handbags, luggage and motor car components. They are thermoformable and can be laminated to fabrics or other materials.</p> |
