PURPOSE: To perform the photo-crosslinking of a PE article useful as a heat- insulation material for roof, etc., in a short time and high efficiency at a low cost by irradiating a sheet or foamed PE article containing a benzophenone-type photo-initiator at a specific concentration with excimer laser beam.
CONSTITUTION: This photo-crosslinking process is carried out by incorporating a PE raw material with preferably 0.01-1wt.% of a benzophenone-type compound such as benzophenone of formula I or 4-chlorobenzophenone of formula II as a photo-initiator, forming a sheet-formed or foamed PE article with an extruder and irradiating the PE article with excimer laser beam. The depth of the crosslinking reaction relative to the thickness of the PE article is arbitrarily adjustable by adjusting the concentration of the photo-initiator to enable the formation of PE article meeting the purpose.
SAKKA FUJIO
TANAKA HIDEKI
FUJII HITOSHI
SAKAI KIYOAKI
