Polyisocyanurate foam comprising reaction product of a polyisocyanate and a polyol mixture comprising a carboxylic ester polyol and a resole polyether polyol using a catalyst comprising dimethylethanolamine and an alkali metal salt of a carboxylic acid

A method for manufacturing rigid urethane-modified isocyanurate foam product comprising the steps of:

• admixing component streams to form a fluent reaction mixture thereof;
• flowing the reaction mixture from admixing step to a curing zone and containing said reaction mixture until a rigid foam product is obtained;
• said component streams comprising a first, polyol-containing reactant stream comprising a major portion of polyether-polyol, a minor portion of polyol ester of aromatic polyacid and alkanediol, and a catalyst component consisting essentially of dimethylethanolamine;
• a second, polyisocyanate reactant stream comprising a major portion of polynuclear aromatic polyisocyanate in sufficient amount to provide isocyanurate as the major recurring polymer unit;
• a third stream comprising sufficient alkali metal salt of carboxylic acid solution to constitute an effective co-catalyst when mixed with the amine catalyst of the first stream;
• at least one of said streams containing a reaction-promoting amount of water, blowing agent, and cell modifier;
• and flame retardant material.

In a rigid, thermally-insulating urethane-modified polyisocyanurate foam obtained by reacting sufficient polynuclear aromatic polyisocyante with a minor amount of polyol in the presence of a blowing agent to form a polymeric foam having isocyanurate as the dominant recurring polymer unit;

• the improvement which comprises:
• a polyol reactant containing a major amount of alkoxylated resole-based phenol-formaldehyde type polyether-polyol and a minor amount of a polyester-polyol consisting essentially of the diethylene glycol ester of mixed bi phenyl di and tri carboxylic acids;
• and
• a water-promoted cocatalyst system consisting essentially of tertiary amine and an alkali metal salt of carboxylic acid.