| 摘要 |
PURPOSE:To impart curability which is hardly affected by ambient temp., to prolong a pot life and to improve adhesion, by using a catalyst mixture of a lead catalyst and a tin catalyst in a specified molar ratio in preparing polyurethane sealing materials other than those of one-pack type. CONSTITUTION:A polyurethane prepolymer (A) mainly composed of a polyol (e.g., polyethylene glycol) and a polyisocyanate (e.g., tolylene diisocyanate) is combined with a curing catalyst (B) obtd. by mixing a lead catalyst with a tin catalyst in a molar ratio of lead to tin of 30:1-1.2:1 to obtain a sealant compsn. for polyurethane sealing materials other than those of one-pack type. Examples of the lead catalyst are lead caprylate, lead naphthenate, etc. Examples of the tin catalyst are dibutyltin dilaurate, tin caprylate, etc.
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