USE OF EPOXY COMPOUNDS AS CARBON DIOXIDE SCAVENGERS IN PIR COMPRISING FOAMS FOR SUPERIOR THERMAL INSULATION PROPERTIES
A reactive composition for making a PIR comprising foam at an isocyanate index of at least 120, said composition comprising at least an isocyanate composition comprising one or more isocyanate compounds, an isocyanate-reactive composition comprising one or more isocyanate-reactive compounds, at least one PIR promoting catalyst, at least one physical blowing agent with a lambda gas ≤12 mW/m·K at 10° C., at least one CO 2 scavenging compound selected from at least one epoxy compound, and optionally a catalyst promoting epoxy reaction with CO 2 characterized in that the amount of isocyanate-reactive compounds in the reactive composition is at least 10 wt % calculated on the total weight of the reactive composition, or at least more than the amount of epoxy compounds and the molar amount of epoxy compounds in the reactive composition is at least 7.8 times higher than the molar amount of CO 2 formed by the water present in the reactive composition after reaction with isocyanates.
1 . A composition for making a PIR comprising foam at an isocyanate index of at least 120, wherein said composition comprises:
a) An isocyanate composition comprising one or more isocyanate compounds, and
b) An isocyanate-reactive composition comprising one or more isocyanate-reactive compounds, and
c) At least one PIR promoting catalyst, and
d) At least one physical blowing agent with a lambda gas ≤12 mW/m·K at 10° C., and
e) At least one CO 2 scavenging compound selected from at least one epoxy compound having an equivalent weight lower than 300 g/mol, and
f) Optionally a catalyst promoting epoxy reaction with CO 2
Characterized in that the amount of isocyanate-reactive compounds in the reactive composition is at least 10 wt % calculated on the total weight of the reactive composition and the molar amount of epoxy compounds in the reactive composition is at least 7.8 times higher than the molar amount of CO 2 formed by the water present in the reactive composition after reaction with isocyanates.
2 . The reactive composition according to claim 1 wherein the amount of isocyanate-reactive compounds in the reactive composition is at least 10 wt % calculated on the total weight of the reactive composition.
3 . The reactive composition according to claim 1 wherein the molar amount of epoxy compounds in the reactive composition is at least 10 times higher than the molar amount of CO 2 formed by the water present in the reactive composition after reaction with isocyanates.
4 . The reactive composition according to claim 1 wherein the maximum amount of all the epoxy compounds in the reactive composition is <25 wt %, calculated on the total weight of the reactive composition.
5 . The reactive composition according to claim 1 wherein the at least one epoxy compound is selected from epoxy compounds having equivalent weight lower than 300 g/mol and wherein the at least one epoxy compound used is liquid at 20° C.
6 . The reactive composition according to claim 1 wherein the catalyst used for promoting epoxy reaction with CO 2 is selected from ammonium salts.
7 . The reactive composition according to claim 1 wherein the at least one physical blowing agent having a lambda gas value ≤12 mW/m·K@10° C. is selected from an HFO blowing agent, an HCFO blowing agent, a hydrocarbon, and mixtures thereof
8 . The reactive composition according to claim 1 wherein the at least one physical blowing agent having a lambda gas value ≤12 mW/m·K@10° C. is selected from chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), and mixtures thereof.
9 . The reactive composition according to claim 1 wherein the polyisocyanate compounds are selected from a toluene diisocyanate, a methylene diphenyl diisocyanate, a polyisocyanate composition comprising a methylene diphenyl diisocyanate, or a mixture of such polyisocyanates.
10 . The reactive composition according to claim 1 wherein the one or more isocyanate reactive compounds comprise polyols and polyol mixtures having average hydroxyl numbers of from 50 to 1000 and hydroxyl functionalities of from 2 to 8.
11 . The reactive composition according to claim 1 wherein the blowing agent is present in an amount of 1 to 60 parts by weight per hundred parts by weight isocyanate reactive compounds.
12 . The reactive composition according to claim 1 further comprising beside the blowing agents having a lambda gas value ≤12 mW/m·K at 10° C. additional blowing agents having a lambda gas value >12 mW/m·K at 10° C. and wherein the ratio of blowing agents having a lambda gas value ≤12 mW/m·K at 10° C. to the additional blowing agents is in the weight ratio 95/5 up to 5/95 calculated on the total weight of all blowing agents.
13 . A process for making a PIR comprising insulation foam, said process comprising combining and/or mixing the ingredients of the reactive composition according to claim 1 at an isocyanate index of at least 120, preferably at least 150, more preferably at least 200, most preferably at least 250.
14 . The process according to claim 13 further including a step of sealing the foam with a gas diffusion tight sealing wherein at least 50% of the foam surfaces are covered with the gas diffusion tight sealing.
15 . The process according to claim 13 wherein the gas diffusion tight sealing is selected from metal foils, gas barrier polymer layers, a thermoplastic polymer, and combinations thereof.
16 . The process according to claim 13 further including after sealing the foam a step of ageing the foam, said ageing step includes keeping the foam at a given temperature above room temperature until a stable low lambda value is obtained.
17 . A stabilized PIR comprising insulation foam made using the process according to claim 13 wherein the wt % of CO 2 in the stabilized aged foam is between 0 and 2 wt %, calculated on the total weight of the stabilized aged foam.
18 . The stabilized PIR comprising insulation foam according to claim 17 having a foam density <45 kg/m 3 and a stabilized thermal conductivity <20 mW/m·K at 10° C.
19 . The stabilized PIR comprising insulation foam according to claim 17 having a foam density >45 kg/m 3 and a stabilized thermal conductivity <25 mW/m·K at 10° C.
20 . A thermal insulator comprising the polyisocyanurate (PIR) comprising insulation foam according to claim 17 .