| 摘要 |
<p>A porous material is rendered waterproof by impregnation with a water-swellable elastomer which increases in volume by 50-500% when saturated with water. In Example 49, a block polymer is prepared from an adipic acid-poly-propylene oxide prepolymer and a succinic acid-polyethylene oxide prepolymer. In Example 52, a polyester is prepared from terephthalic acid, maleic acid, and polyethylene oxide. In Example 56 a polyester is prepared from maleic acid, diethylene glycol and polyethylene glycol. In Example 57, a cross-linked resin is prepared from an elastomeric polyurea (polydecamethyleneurea-ethylene oxide), a hydrophilic copolymer (N,N-dimethylacrylamide-acrylamide), and a methylol resin (melamine-formaldehyde). In Example 58, polyhexamethylene tetrasulphide is reacted with a copolymer derived from butadiene and acrylic acid. These polymers are dissolved in, e.g., toluene, ethanol, methanol, acetone, MEK, DMF or methylene dichloride and in Examples 55-58 are mixed with suitable addition polymers.ALSO:A porous material is rendered water-proof by impregnation with a water-swellable elastomer which increases in volume by 50-500% when saturated with water. The water-swellable elastomer may be derived from a hydrophobic elastomer-forming monomer which is modified by copolymerisation. A copolymer may be further modified by hydrolysis with alkali metal hydroxide and/or reacted with another copolymer. The hydrophobic elastomer-forming monomer may be butadiene, chloroprene, or isoprene. The water swellable elastomer may alternatively be a polyester, polyurea, polyurethane, polyamide, or polysulphide. The water swellable elastomer is applied in a solvent. The porous material may be fabric, paper, or leather. Curing is effected after impregnation. A water repellent finish may be applied before or after curing. A large number of examples is given.</p> |
