Abstract: This invention relates to a method for preparing glassy fibers having protuberances studded on the surface of the fiber, characterized in that each protuberance comprises an unmelted component of the starting materials and is formed on the surface of the fiber by fiberizing the partially unmelted starting materials by a spinner or blowing technique.

Abstract: A method of preparing asbestos articles to exhibit dustproof effects in secondary processing without degradation of the inherent properties of the asbestos articles comprises the step of immersing the asbestos article in a treating agent comprising formaldehyde, a water-soluble organic compound capable of reacting with formaldehyde to form a water-insoluble compound under weakly alkaline conditions in an atmosphere maintained at a high temperature and a high humidity, a plasticizer, and a water-soluble macromolecular substance having film forming properties, and the steps of infusing the asbestos article with a weakly alkaline solution and first reacting the asbestos article in an atmosphere maintained at a high temperature and high humidity, and subsequently heat treating the resulting product to obtain the final product. The final product is impregnated in the interior substrate thereof by 0.5 to 10 wt.% of the water-insoluble compound, has a surface layer of 0.04 to 0.09 wt.