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 head and 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 300.degree. K. or less; and
- b) a polyol composition comprising water and compounds having at least two isocyanate active hydrogen, wherein the average functionality of said compounds in the polyol composition is greater than 4.0, wherein the average hydroxyl number of the compounds having at least two isocyanate active hydrogens is less than 400, 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 formulated 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 hydrogen is less than 400.
Parent Case Info
This is a division of application Ser. No. 08/272,401 filed Jul. 8, 1994, now U.S. Pat. No. 5,430,071.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
Country |
Parent |
272401 |
Jul 1994 |
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