| 摘要 |
PURPOSE:To obtain a foam, having a prescribed thickness, a prescribed average bubble diameter and a prescribed foaming degree, excellent in uniformity and insulating properties without causing the buckling, etc., and suitable as an insulating layer, etc., of a coaxial cable by carrying out the expansion with a physical foaming agent such as a rare gas and a chemical foaming agent. CONSTITUTION:The foam is obtained by carrying out the expansion with a physical foaming agent, composed of a rare gas such as argon gas or the rare gas and one or more of gaseous carbon dioxide and nitrogen and containing >=40vol.% content of the rare gas [used in an amount of preferably 0.001-10 pts.wt. based on 100 pts.wt. organic polymer to be foamed] and a chemical foaming agent such as azodicarbonamide [used in an amount of preferably 0.1-10 pts.wt. based on 100 pts.wt. organic polymer to be foamed]. This foam has >=1mm thickness, 200-500mum average cell diameter of >=80% cells present therein and 75-85% foaming degree. |
