| 摘要 |
PROBLEM TO BE SOLVED: To provide a sealing material which has a high whiteness at its surface, has a high heat resistance and chemical resistance, exerts a high durability and shows little a reduced temperature increase upon radiation of infrared rays, and a preparation process thereof. SOLUTION: A white colored elastomer sealing material comprises a perfluoro elastomer and a composition containing a white pigment and has a surface of which the whiteness, determined by the W(Lab) calorimetric system under a standard illuminant C condition, is 90 or larger. In a preparation process of a sealing material having a surface of which the whiteness, determined by the W(Lab) calorimetric system under a standard illuminant C condition, is larger than 75, a sealing material is molded from a perfluoro elastomer and a composition containing a white pigment, and the molded sealing material is either soaked in a hydrogen peroxide aqueous solution, irradiated with an ultraviolet ray or exposed to ozone for a time sufficient for increasing at least 5 points the initial whiteness of the sealing material.
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