Polyurethane and polyisocyanurate rigid foams for roofing insulation

Patent metadata

Field	Value
Publication number	US-9522973-B2
Application number	US-201213633312-A
Country	US
Kind code	B2
Filing date	Oct 2, 2012
Priority date	Oct 2, 2012
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

Polyurethane foams having a NFPA 101 Class B rating (ASTM E-84) which pass the FM 4450 calorimeter Test are produced by reacting: (a) an organic polyisocyanate, (b) at least one polyether polyol or polyester polyol with a nominal hydroxyl functionality of at least 2.0, (c) a blowing agent composition and (d) at least one halogen-free flame retardant. The blowing agent composition includes: (1) no more than 10% by weight, based on total weight of the foam-forming composition, of one or more hydrocarbons having an LEL less than 2% by volume in air, and/or (2) a hydrocarbon having an LEL greater than 2% by volume in air, and (3) up to 1% by weight, based on total weight of foam-forming composition, of water.

First claim

What is claimed is:

1. A polyurethane foam having a density less than 1.8 pounds per cubic foot and having a NFPA 101 Class B rating in accordance with the requirements of ASTM E-84 and which passes an FM 4450 calorimeter Test comprising the reaction product of a foam forming composition comprising:
a) at least 55% by weight based on total weight of foam-forming composition of an organic polyisocyanate,
b) an isocyanate-reactive composition comprising at least one polyether polyol or polyester polyol with a nominal hydroxyl functionality of at least 2.0,
c) a blowing agent composition comprising:
(1) greater than 0 to no more than 10% by weight, based on total weight of foam-forming composition, of one or more hydrocarbons having an LEL less than 2% by volume in air,
and
(2) greater than 0 and no more than 5% by weight, based on total weight of foam-forming composition, of a hydrocarbon having an LEL greater than 2% by volume in air,
and
(3) greater than 0 and up to 1% by weight, based on total weight of foam-forming composition, of water,

and
d) at least one halogen-free flame retardant;

and wherein the polyurethane foam-forming composition contains no halogenated flame retardant or halogenated blowing agent.

2. The foam of claim 1 in which the one or more hydrocarbons having an LEL less than 2% by volume in air comprises n-pentane.

3. The foam of claim 2 in which the hydrocarbon having an LEL greater than 2% by volume in air is methyl formate.

4. The polyurethane foam of claim 1 , with the proviso that the polyurethane foam-forming composition contains no ammonium polyphosphate.

Assignees

• Covestro Llc

Inventors

• Combs George G
• Pigott Susan C

Classifications

• C08G18/42 Primary

  Polycondensates having carboxylic or carbonic ester groups in the main chain · CPC title

• C08G2101/0025

  Chemistry & Metallurgy · mapped topic

• C08J9/149

  Mixtures of blowing agents covered by more than one of the groups C08J9/141 - C08J9/143 · CPC title

• C08J9/141 Primary

  Hydrocarbons · CPC title

• C08J9/0014

  Use of organic additives · CPC title