A REACTION MIXTURE FOR MANUFACTURING AN INORGANIC-FILLER BASED CLOSED-CELL RIGID POLYURETHANE OR POLYISOCYANURATE CONTAINING FOAM
The present invention relates to a reaction mixture for manufacturing an inorganic-filler based closed-cell rigid polyurethane or polyisocyanurate (PU or PIR) containing foam having a calorific value below 6 MJ/kg, preferably below 4.5 MJ/kg, more preferably below 3 MJ/kg, measured according to EN ISO 1716, the reaction mixture comprising: At least one polyisocyanate-containing compound; At least one isocyanate-reactive compound; An inorganic filler composition; At least one physical blowing agent; characterised in that said inorganic filler composition has bulk density higher than 2 g/cm 3 , preferably higher than 2.1 g/cm 3 , more preferably higher than 2.2 g/cm 3 , even more preferably higher than 2.4 g/cm 3 .
1 . A reaction mixture for manufacturing an inorganic-filler based closed-cell rigid polyurethane or polyisocyanurate containing foam having a calorific value below 6 MJ/kg, measured according to EN ISO 1716, the reaction mixture comprising:
At least one polyisocyanate-containing compound;
At least one isocyanate-reactive compound;
An inorganic filler composition;
At least one physical blowing agent;
Optionally, a surfactant, a chemical blowing agent, a catalyst, a chain extender, a crosslinker, an antioxidant, a fire retardant and/or mixtures thereof;
characterised in that said inorganic filler composition has bulk density higher than 2 g/cm 3 .
2 . The reaction mixture according to claim 1 , wherein said inorganic filler composition is present in an amount of at least 70 wt relative to the total weight of said reaction mixture, without taking into account the weight of said at least one physical blowing agent.
3 . The reaction mixture according to claim 1 , wherein said inorganic filler composition comprises a first inorganic filler selected from the group comprising bismuth oxide, zirconium (IV) oxide, iron (III) oxide, barium sulfate, barium carbonate, titanium (IV) oxide, aluminium oxide, magnesium oxide and combinations thereof.
4 . The reaction mixture according to claim 1 , wherein said inorganic filler composition has a thermal conductivity lower than 25 W/m.K.
5 . The reaction mixture according to claim 1 , wherein said first inorganic filler has a particle size distribution with a d90 value comprised in the range 10-2000 μm.
6 . The reaction mixture according to claim 1 , wherein said inorganic filler composition further comprises a second inorganic filler having bulk density lower than 2 g/cm 3 .
7 . The reaction mixture according to claim 1 , wherein said second inorganic filler is selected from the group comprising barium sulfate, aluminium silicate, magnesium silicate, calcium fluoride, Iron (III) sulfate, calcium sulfate, calcium carbonate, magnesium sulfate, silicon oxide, sodium carbonate, aluminium hydroxide, magnesium hydroxide, sodium chloride, calcium chloride, perlite and combinations thereof.
8 . The reaction mixture according to claim 1 , wherein said at least one physical blowing agent is selected from the list comprising isobutene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydro(chloro)fluoroolefins (HFOs/HCFOs), dialkyl ethers, cycloalkylene ethers, ketones, fluorinated ethers, perfluorinated hydrocarbons, hydrocarbons and mixtures thereof.
9 . The reaction mixture according to claim 1 , wherein said at least one polyisocyanate-containing compound is selected from the group comprising toluene diisocyanate, methylene diphenyl diisocyanate, polyisocyanate composition comprising methylene diphenyl diisocyanate and mixtures thereof.
10 . The reaction mixture according to claim 1 , wherein said at least one isocyanate-reactive compound is a polyol having average hydroxyl number of from 50 to 1000 and hydroxyl functionality of from 2 to 8.
11 . The reaction mixture according to claim 1 , comprising a CO 2 scavenger.
12 . An inorganic-filler based closed-cell rigid polyurethane or polyisocyanurate containing foam having a calorific value below 6 MJ/kg, measured according to EN ISO 1716.
13 . The foam according to claim 12 , having a value below 35 mW/m.K at 10° C., measured according to ISO 8301.
14 . The foam according to claim 12 , having a density lower than 400 kg/m 3 , measured according to ISO 845.
15 . The foam according to claim 12 , wherein the percentage of closed cells is higher than 50% measured according to ISO 4590.
16 . The foam according to claim 12 , obtained by mixing the components of the reaction mixture according to claim 12 .
17 . Article An article comprising a foam according to claim 12 .
18 . The article according to claim 17 , wherein the article is one or more of a composite panel, insulation board, external thermal insulation composite system (ETICS), pipe, garage door, appliance, spray-foam insulation.