| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a heat insulator which prevents the occurrence of molding defects of a core material. <P>SOLUTION: A heat insulator comprises: a core material which contains a plurality of small particles with an average particle diameter D<SB POS="POST">S</SB>equal to 5 nm or more and less than 50 nm and a specific gravity C<SB POS="POST">S</SB>formed of a first inorganic compound containing silica, and a plurality of large particles with an average particle diameter D<SB POS="POST">L</SB>of 50 nm or more and 100 μm or less and a specific gravity C<SB POS="POST">L</SB>formed of a second inorganic compound; and a sheath material which accommodates the core material. The heat insulator has a ratio M<SB POS="POST">S</SB>/M<SB POS="POST">L</SB>of 0.035C<SB POS="POST">S</SB>/C<SB POS="POST">L</SB>to 3, where M<SB POS="POST">S</SB>represents the total mass of the small particles and M<SB POS="POST">L</SB>represents the total mass of the large particles. <P>COPYRIGHT: (C)2012,JPO&INPIT |
