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A process for producing a rigid polyurethane foam by use of a decreased amount of a CFC blowing agent and an increased amount of water used as a blowing agent, maintaining a high degree of heat insulation and improving the deterioration in friability of the product. The catalyst is one of the imidaz

A process for producing a rigid polyurethane foam by use of a decreased amount of a CFC blowing agent and an increased amount of water used as a blowing agent, maintaining a high degree of heat insulation and improving the deterioration in friability of the product. The catalyst is one of the imidazoles represented by the formula (I): [Figure] (I) where R1 is alkyl having 1 to 4 carbons, benzyl, dimethylaminopropyl, or hydroxyalkyl having 1 to 3 carbons; R2 is hydrogen, alkyl having 1 to 4 carbons, allyl, or benzyl; and R3 and R4 are independently hydrogen, methyl, or hydroxymethyl.

대표청구항 ▼

A process for producing a rigid polyurethane foam having a foam density of from 10 to 60 kg/m3 by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent, and a foam stabilizer; said blowing agent comprising water in an amount of not less than 2.0 parts by weight and a

A process for producing a rigid polyurethane foam having a foam density of from 10 to 60 kg/m3 by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent, and a foam stabilizer; said blowing agent comprising water in an amount of not less than 2.0 parts by weight and a halogenated hydrocarbon in an amount of not more than 35 parts by weight based on 100 parts by weight of the polyol; said catalyst being at least one of the imidazoles represented by the formula (I): [Figure] (I) where R1 is alkyl having 1 to 4 carbons, benzyl, dimethylaminopropyl, or hydroxyalkyl having 1 to 3 carbons; R2 is hydrogen, alkyl having 1 to 4 carbons, allyl, or benzyl; and R3 and R4 are independently hydrogen, methyl, or hydroxymethyl.