Polyurethanes with covalently bound photoinitiator-units

摘要

A polyurethane with a number-average mol. wt. (Mn) of more than 2700 which is essentially self-dispersible in water, obtained by reaction of: (a) polyisocyanate(s) with: (b) polyol(s) comprising: (b1) 9-100 mol% polyol(s) with a mol. wt. of at least 500; and (b2) 0-91 mol% polyol(s) with a mol. wt. of less than 500, and (c) photoinitiator(s) of formula (I): R = a group of formula (II), or -CR7R8R9, -P(O)(R10)2 or -SO2R11; R1, R2, R5, R6 and/or R9 = used for incorporation into the polyurethane and the others comprise H, 1-12C alkyl or alkoxy, halogen, CN, NO2 and/or sulpho; R3, R4 = H or COOH, or both together are S; R7, R8 = H, 1-12C alkyl, alkenyl or alkoxy, or phenyl, or both together are O or 2-6C alkylene; R9 = OR11, N(R11)2, N-piperidyl, N-piperazyl or N-morpholino; R10 = 1-12C alkyl or alkanoyl, phenyl or benzoyl (each optionally substituted with halogen or 1-12C alkyl or alkoxy); R11 = H, 1-6C alkyl, 1-12C alkoxy or phenyl (each optionally substituted with OH, NHR10, NH2 or SH), or two R11 groups are 2-5C alkylene; if R9 is OR11 and R11 is H, R7 and R8 in combination cannot be H and phenyl. Also claimed are: (i) a process for the production of self-dispersible polyurethane by reacting components (a)-(c) as above to give polyurethane with an Mn of more than 2700; (ii) aqueous polyurethane dispersions containing this polyurethane; (iii) a process for the production of aqueous polyurethane dispersions by reacting (a)-(c) as above, optionally neutralising the product and dispersing in water; (iv) coating compositions obtained by dissolving or dispersing the polyurethane in water together with other polymeric binders and other appropriate conventional additives; (v) a process as described in (iv) for the production of coating materials; (vi) a process for coating objects by applying such materials by means of conventional technology, then drying the coating and crosslinking it by irradiation with UV light; and (vii) objects coated with polyurethane as above.