Claims
- 1. A method of making a closed cell rigid polyisocyanate based foam, comprising ejecting an isocyanate stream and a formulated polyol composition stream at a weight ratio of 0.9:1 to 1.3:1, respectively, through a dispensing headand to form a froth, wherein the formulated polyol composition stream comprises:
- a) a liquid C.sub.1 -C.sub.4 hydrofluorocarbon blowing agent having a boiling point of 300K. or less; and
- b) a polyol composition comprising water and compounds having at least two isocyanate active hydrogens, wherein the average functionality of said compounds in the polyol composition is greater than 4.0;
- and wherein the isocyanate stream and the formulated polyol composition stream are reacted at an isocyanate index of 100 to 130.
- 2. The method of claim 1, wherein the hydrocarbon comprises 1,1,1,2-tetrafluoroethane.
- 3. The method of claim 2, wherein the polyol composition comprises:
- i) a hydroxyl terminated polyol initiated with at least one initiator comprising sucrose, said polyol having a pH in the range of 6-8;
- b) water in an amount of 1.5 to 4.0 wt.% based on the weight of the polyol composition; and
- c) a tertiary amine ether blow catalyst in an amount of 0.5 weight percent or greater based on the weight of the polyol composition.
- 4. The method of claim 2, wherein the formulated polyol composition stream has a viscosity of 550 cP or less, when measured at 78.degree. F. and 80 p.s.i.g.
- 5. The method of claim 4, wherein the formulated polyol composition stream has a viscosity of 400 cP or less.
- 6. The method of claim 2, wherein iscoyanate stream and the formualted polyol composition stream are propelled to the dispensing head by an inert gas.
- 7. The method of claim 2, wherein the isocyanate stream is reacted with the polyol composition stream at an isocyanate index of greater than 105 to 115 and at a weight ratio of 1.1:1 to 1.15:1.
- 8. The method of claim 2, wherein the polyol composition stream and the isocyanate stream are ejected under pressure from an inert gas through a static mixer.
- 9. The method of claim 2, wherein the average hydroxyl number of the compounds having at least two isocyanate active hydrogens is less than 400.
Parent Case Info
This is a division of application Ser. No. 08/419,202 filed Apr. 10, 1995, now U.S. Pat. No. 5,451,614.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
Country |
Parent |
419202 |
Apr 1995 |
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