To obtain a rock wool, board ensured not to develop any blister thereon.
First, rock wool is subjected to a process just like papermaking to produce a base board material 2. Secondly, the surface of the base material 2 is coated with slurry 9 which, in turn, is sprinkled with a polymeric absorptive powder 12. Thirdly, both the base material 2 and slurry 9 are dried. Thus, owing to the water/moisture absorbed by the polymeric powder 12 from both the base material 2 and slurry 9 and held by the polymeric powder 12, water vapor generation speed during the drying process can be delayed to retard hardening and drying of the slurry 9. Therefore, film formation due to hardening of the surface of the slurry 9 before releasing the water/moisture as water vapor from the inside of both the base material 2 and slurry 9 can be prevented, and thereby, water vapor can be released smoothly through the surface of the slurry 9 from the inside of both the base material 3 and slurry 9.
OTSU JUNICHI
YABU SADAO
Next Patent: WATERPROOF MATERIAL FOR FAIR-FACED CONCRETE AND POLYMER FOR CEMENT ADMIXTURE