VACUUM ASSISTED PROCESS TO MAKE CLOSED CELL RIGID POLYURETHANE FOAMS USING MIXED BLOWING AGENTS
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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Abstract
Rigid polyurethane foam is made in a vacuum assisted process using a blowing agent mixture that includes water and hydrofluoroolefin and/or hydrofluorochloroolefin. In preferred embodiments, the blowing agent mixture further includes a hydro carbon such as cyclopentane.
10 Citations
15 Claims
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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.
- 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;
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2. 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, a hydrocarbon blowing agent and at least one HFO or HCFO, the blowing agent mixture containing 5 to 60 mole percent water and the mole ratio of the hydrocarbon and the HFO or HCFO being 5;
95 to 95;
5;
(b) injecting the reactive foam-forming system under a reduced atmospheric pressure 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. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- 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;
Specification