| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent generation of pin holes in a vacuum heat insulation material pierced therein from the inside even when its outer wrapping material uses a thin innermost layer, thereby dispensing with a bag breakage inspection process and suppressing temporal gas intrusion due to permeation through the innermost layer. <P>SOLUTION: A glass fiber constituting a core material 2 is made of a glass composition composed of 50-70 wt.% SiO<SB>2</SB>, 0-7 wt.% Al<SB>2</SB>O<SB>3</SB>, 8-20 wt.% of Na<SB>2</SB>O and K<SB>2</SB>O in combination, 0-6 wt.% MgO, 2-15 wt.% CaO, and not more than 3 wt.% of other ingredients, where the percentages by weight of these ingredients total 100% and the surface tension of a melt is not more than 300 mN/m. In addition, the innermost layer of the outer wrapping material 4 is a 15-50μm thick resin film. This decreases the frequency of cutting in glass fiberization, dramatically reducing the probability of shot entry. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
