Mixture obtained by reacting polyol and anhydride and its use in polyisocyanates for making polyisocyanurates
Isocyanurate-reactive mixture obtained by reacting an anhydride and a polyol; process for making it; polyisocyanate composition comprising this mixture; binder composition comprising such a polyisocyanate composition; the use of such a polyisocyanate composition and/or binder composition for making a polyisocyanurate and such polyisocyanurates.
1. A method for making a polyisocyanurate comprising:
forming an isocyanate-reactive mixture comprising:
a trimerization catalyst comprising 1-12 carbon atoms; and
the reaction product of an anhydride and a polyol;
wherein the polyol has an average equivalent weight of 100-2500 and an average nominal hydroxyl functionality of 2-8;
wherein the trimerization catalyst is selected from the group consisting of alkali metal carboxylates, which are selected from the group consisting of potassium acetate, potassium hexanoate, potassium ethylhexanoate, potassium octoate, and potassium lactate, quaternary ammonium carboxylates and mixtures thereof,
wherein the molar amount of the anhydride ranges from 0.1 to 99% of the hydroxyl equivalent amount of the polyol, and
wherein the ratio of the number of carboxylic acid groups to the number of ester groups, both formed in the reaction between the anhydride groups and the polyol, is 0.9-1.1 to 1 and wherein at least 60% of the anhydride groups has been converted;
forming a polyisocyanate composition by adding the isocyanate-reactive mixture to a polyisocyanate compound at a temperature in the ranqe of 5° C. to 45° C.; and
forming the polyisocyanurate by heating the polyisocyante composition to a temperature ranging from 50° C. to 350° C.
2. The method according to claim 1 wherein the temperature for forming the polyisocyanurate ranges from 70° C. to 280° C.
3. The method according to claim 1 , wherein the anhydride is selected from phthalic anhydride, trimeliitic anhydride, or combinations thereof.
4. The method according to claim 1 , wherein the anhydride is phthalic anhydride.
5. The method according to claim 1 , wherein the polyol is a polyether polyol having an average nominal hydroxyl functionality of 2-4 and an oxyethylene content of at least 50% by weight calculated on the weight of the polyether polyol.
6. The method according to claim 1 , wherein the molar amount of the anhydride ranges from 0.2 to 50% of the hydroxyl equivalent amount of the polyol.
7. The method according to claim 1 , wherein the molar amount of the anhydride ranges from 0.3 to 30% of the hydroxyl equivalent amount of the polyol.
8. The method according to claim 1 , wherein the amount of trimerization catalyst is 0.002-5% by weight based on the weight of the mixture.
9. The method according to claim 1 , wherein the anhydride and the polyol are reacted at ambient pressure and at a temperature ranging from 10 to 140° C. in the presence of the trimerization catalyst.
10. The method according to claim 9 , wherein the temperature ranges from 10 to 100° C. in the presence of the trimerization catalyst.
11. The method according to claim 1 , wherein the isocyanate-reactive mixture is added to the polyisocyanate composition in such relative amounts that the index of the polyisocyanate composition is 150-15000.
12. The method according to claim 1 , wherein the temperature for adding the isocyanate-reactive mixture to a polyisocyanate compound is in the range of 5° C. to 30° C.
13. The method according to claim 1 , wherein the polyisocyanate composition is part of a binder composition further comprising a material which is to be bonded, wherein the amount of material which is to be bonded is 0.01-100 times the amount of the polyisocyanate composition.