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VACUUM ASSISTED PROCESS TO MAKE CLOSED CELL RIGID POLYURETHANE FOAMS USING MIXED BLOWING AGENTS

  • US 20160200889A1
  • Filed: 09/18/2014
  • Published: 07/14/2016
  • Est. Priority Date: 09/19/2013
  • Status: Abandoned Application
First Claim
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1. A process for preparing a cavity-filling closed cell rigid polyurethane foam comprising (a) preparing a reactive foam-forming system comprising as components at least one organic polyisocyanate;

  • a polyol mixture having an average functionality of at least 3.0 hydroxyl groups per molecule and an average hydroxyl equivalent weight of 75 to 250;

    a blowing agent mixture containing water, at least one HFO or HCFO and optionally at least one hydrocarbon, the blowing agent mixture containing 5 to 60 mole percent water and at least 2 mole percent of the HFO or HCFO;

    (b) injecting the reactive foam-forming system into a cavity and expanding the foam-forming system under reduced atmospheric pressure (c) maintaining the reduced atmospheric pressure at least until a gel forms and further curing the reactive foam-forming system to produce a closed cell rigid polyurethane foam having a density of less than about 40 kg/m3 and a thermal conductivity of less than 19 mW/m·

    K at 10°

    C. average plate temperature, according to ISO 12939/DIN 52612.

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