Amine-initiated polyols and rigid polyurethane foam made therefrom
Polyether polyols are initiated with aminocyclohexanealkylamines such as isophoronediamine and 1,8-diaminop-menthane. The polyols are useful in making rigid polyurethane foams, especially foams for pour-in-place applications, where they give a good combination of low k-factor and short demold times.
1. A process for preparing a rigid polyurethane foam, comprising
a) forming a reactive mixture containing at least
1) a mixture of an amine-initiated polyol that has a functionality of 3.7 to 4.0, a hydroxyl equivalent weight of from 100 to 130 and which is a reaction product of 1,8-diamino-p-menthane and a C 2 -C 4 alkylene oxide with at least one polyether polyol having a functionality of from 4.5 to 7 and a hydroxyl equivalent weight of 100 to 175, provided that such a mixture contains at least 5% by weight of the amine-initiated polyol;
2) at least one hydrocarbon, hydrofluorocarbon, hydrochlorofluorocarbon, fluorocarbon, dialkyl ether or fluorine-substituted dialkyl ether physical blowing agent; and
3) at least one polyisocyanate;
wherein the reactive mixture further contains water, and
b) subjecting the reactive mixture to conditions such that the reactive mixture expands and cures to form a rigid polyurethane foam.
2. The process of claim 1 , wherein the reaction mixture further contains at least one different amine-initiated polyol having an average functionality of from 2.0 to 4.0 and a hydroxyl equivalent weight of from 100 to 225.
3. The process of claim 2 , wherein the reaction mixture further contains a non-amine-initiated polyol having a functionality of from 2.0 to 3.0 and a hydroxyl equivalent weight of from 90 to 500.
4. A rigid polyurethane foam made in accordance with claim 1 .
5. The foam of claim 4 , which is an appliance insulation foam, a layer of a laminated board, pipe insulation or a vehicle dampening member.
6. A polyol mixture comprising:
a) from 10 to 50%, based on the combined weights of components a), b), c) and d), of an amine-initiated polyol that has a functionality of 3.7 to 4.0, a hydroxyl equivalent weight of from 100 to 130 and which is a reaction product of 1,8-diamino-p-menthane and a C 2 -C 4 alkylene oxide;
b) from 20 to 70%, based on the combined weights of components a), b), c) and d), of a non-amine-initiated polyether polyol having an average functionality of from 4.5 to 7 and a hydroxyl equivalent weight of from 100 to 175;
c) from 2 to 20%, based on the combined weights of components a), b), c) and d), of another amine-initiated polyol, different from component a), which has an average functionality of from 2.0 to 4.0 and a hydroxyl equivalent weight of from 100 to 225 and
d) from 0 to 15%, based on the combined weights of components a), b), c) and d), of a non-amine-initiated polyol having a functionality of from 2.0 to 30 and a hydroxyl equivalent weight of from 200 to 500.