Low viscosity (meth)acrylates as reactive additives in reactive compositions for making rigid polyurethane/polyisocyanurate comprising foams
A reactive composition is disclosed for making a polyisocyanurate-polyurethane comprising rigid foam (PIR-PUR), said reactive composition comprising a polyisocyanate composition, an isocyanate-reactive composition, at least one catalyst compound suitable for making the PIR-PUR comprising foam, at least one blowing agent; and optionally one or more surfactants, one or more flame retardants, one or more antioxidants, or combinations thereof characterized in that the reactive composition further comprises a reactive viscosity reducer selected from at least one acrylate and/or methacrylate compound having no isocyanate-reactive groups and having a viscosity at 25° C. below 100 mPa·s.
1. A method for making a polyisocyanurate (PIR) and/or a polyurethane (PUR) comprising rigid foam, the method comprising:
combining and mixing:
a) a polyisocyanate composition comprising one or more polyisocyanate compounds;
b) an isocyanate-reactive composition comprising one or more isocyanate-reactive compounds;
c) at least one catalyst compound suitable for making the polyisocyanurate (PIR) and/or the polyurethane (PUR) comprising foam;
d) at least one blowing agent;
e) acrylate and/or methacrylate compounds as a reactive viscosity reducer wherein the acrylate and/or methacrylate compounds comprise at least one first acrylate and/or methacrylate compound selected from cyclic trimethylolpropane formal acrylate (CTFA), 3,3,5-trimethyl cyclohexyl acrylate (TMCHA), isobornyl acrylate (IBOA), 4-tert-butylcyclohexyl acrylate (TBCHA), benzyl acrylate (BZA), phenol (EO) acrylate (PHEA), benzyl methacrylate (BZMA), phenoxyethyl methacrylate (PHEMA), tetrahydrofurfuryl methacrylate (THFMA), isobornyl methacrylate (IBOMA), and mixtures thereof and at least one second acrylate and/or methacrylate compound having no isocyanate-reactive groups and having 2 or 3 reactive acrylate groups or methacrylate groups and having a viscosity at 25° C.≤30 mPa·s; and optionally
f) one or more surfactants, one or more flame retardants, one or more antioxidants, or combinations thereof;
to form a reactive composition; and
reacting the reactive composition in the absence of a thermal radical initiator to produce the PIR and/or PUR comprising rigid foam; and optionally,
subjecting the PIR and/or PUR comprising rigid foam to a post foaming temperature treatment,
wherein e) the acrylate and/or methacrylate compounds are polymerized by heat generated during the reaction of the reactive composition and during the optional post foaming temperature treatment.
2. The method according to claim 1 , wherein the amount of the reactive viscosity reducer in the reactive composition is in the range 0.1 wt % up to 50 wt % calculated on the total weight of the reactive composition.
3. The method according to claim 1 , wherein the one or more polyisocyanate compounds are selected from the group consisting of a toluene diisocyanate, a methylene diphenyl diisocyanate and a mixture thereof.
4. The method according to claim 1 , wherein the one or more isocyanate-reactive compounds comprise a polyol having an average hydroxyl number of from 50 to 1000 mg KOH/g, and a hydroxyl functionality of from 2 to 8.
5. The method according to claim 1 , wherein the at least one blowing agent is present in an amount of up to 80 parts by weight per hundred parts by weight of the one or more isocyanate-reactive compounds.
6. The method according to claim 1 , wherein the reactive viscosity reducer is added to the isocyanate composition before combining and mixing the isocyanate composition with the isocyanate-reactive composition.
7. The method according to claim 1 , wherein the reactive viscosity reducer is added to the isocyanate-reactive composition before combining and mixing the isocyanate-reactive composition with the isocyanate composition.
8. The method according to claim 1 , wherein the reactive viscosity reducer is added as a separate stream to the reactive composition when combining and mixing the isocyanate-reactive composition with the isocyanate composition.
9. The method according to claim 1 , wherein the method is performed at an isocyanate index of 180 or higher and the at least one catalyst compound is selected from at least one trimerisation catalyst.
10. The method according to claim 1 , wherein the method is performed at an isocyanate index in the range 80-180 and the at least one catalyst compound is selected from at least one polyurethane catalyst.