| 摘要 |
<p>The composition of the lap resistant roll cover of the parent Specification is modified in that the water ionizable compound is sodium nitrate, sodium chloride, sodium sulphate, or the corresponding potassium salts; zinc nitrate, zinc chloride, zinc sulphate, ferrous or ferric chloride, stannous or stannic chloride; acetic, citric, tartaric, lactic or maleic acid; or ammonium or calcium hydroxide. In addition, vegetable protein such as soybean or wheat protein may replace the animal protein. Alums such as potassium aluminium sulphate and sodium aluminium sulphate, and also aluminium sulphate are stated to be unsatisfactory for use in the process of the parent Specification. The synthetic rubber may also have a water vapour permeability of at least 0.8X10-3 grams per sq. cm. per day measured with a humidity differential between that of desiccated air and air at 80 per cent relative humidity at 70 DEG F. Specifications 637,574 and 637,575 are referred to.ALSO:The composition of the lap-resistant roll cover of the parent specification is modified in that the water ionisable compound is sodium nitrate, sodium chloride, sodium sulphate, or the corresponding potassium salts; zinc nitrate, zinc chloride, zinc sulphate, ferrous or ferric chlorides, stannous or stannic chlorides; acetic, citric, tartaric, lactic or maleic acids; or ammonium or calcium hydroxides. In addition, vegetable protein such as soyabean or wheat protein may replace the animal protein. Sand may also be added. Alums such as potassium aluminium sulphate and sodium aluminium sulphate, and also aluminium sulphate are stated to be unsatisfactory for use in the process of the parent Specification. The synthetic rubber may also have a water vapour permeability of at least 0.8 x 10-3 grams per sq. cm per day measured with a humidity differential between that of desiccated air and air at 80 per cent relative humidity at 70 DEG F. Specifications 637,574 and 637,575 are referred to.</p> |
