	US 12,187,836 B2
	Two-component polyurethane casting compound with adjustable pot life
Antonio Corsaro, Regensdorf (CH); and Fabien Choffat, Rüttenen (CH)
Assigned to SIKA TECHNOLOGY AG, Baar (CH)
Appl. No. 17/312,112
Filed by SIKA TECHNOLOGY AG, Baar (CH)
PCT Filed Dec. 18, 2019, PCT No. PCT/EP2019/085952 § 371(c)(1), (2) Date Jun. 9, 2021, PCT Pub. No. WO2020/127485, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 18215604 (EP), filed on Dec. 21, 2018.
Prior Publication US 2022/0025101 A1, Jan. 27, 2022
Int. Cl. C08G 18/22 (2006.01); C08G 18/24 (2006.01); C08G 18/32 (2006.01); C08G 18/38 (2006.01); C08G 18/48 (2006.01); C08G 18/76 (2006.01)

CPC C08G 18/227 (2013.01) [C08G 18/24 (2013.01); C08G 18/3206 (2013.01); C08G 18/3876 (2013.01); C08G 18/4812 (2013.01); C08G 18/4825 (2013.01); C08G 18/485 (2013.01); C08G 18/7657 (2013.01)]

15 Claims

1. A casting compound comprising a polyurethane composition consisting of a first component A and a second component B;

the first component A comprising:

at least one polyol A1 having an OH functionality in the range from 1.5 to 4 and a mean molecular weight (number average) M_n, measured by means of GPC against polystyrene, in the range from 250 to 15 000 g/mol, and

at least one diol A2 having two hydroxyl groups joined via a C2 to C9 carbon chain, and

at least one compound T having at least one thiol group; and

the second component B comprising:

at least one polyisocyanate I that is a form of diphenylmethane 4,4′-, 2,4′-, or 2,2′-diisocyanate (MDI) that is liquid at room temperature and any mixtures of thereof in a form of polymeric MDI or MDI containing proportions of oligomers or derivatives;

wherein:

one of the first component A and the second component B additionally comprises at least one metal catalyst K for the reaction of hydroxyl groups and isocyanate groups that is able to form thio complexes;

the molar ratio of all the thiol groups in the at least one compound T to all metal atoms in the at least one metal catalyst K is between 1:1 and 250:1;

the molar ratio of all NCO groups in the polyisocyanates I to all OH groups in the polyols A1 and A2 is in a range of 0.9:1-1.2:1; and

the polyurethane composition, directly after mixing of components A and B at 23° C., is free-flowing, and has a viscosity, measured at 20° C. on a plate-plate viscometer with plate separation 1 mm and plate diameter 25 mm, of <5000 Pa·s at a shear rate of 0.01 s⁻¹, of <500 Pa·s at a shear rate of 1 s⁻¹, and of <50 Pa·s at a shear rate of 10 s⁻¹.