(Meth)acrylic esters of polyalkoxylated trimethylolpropane

A process for preparing an ester F of alkoxylated trimethylolpropane of the formula IIa

• wherein AO is for each AO independently EO, PO, and BO,
• EO is O—CH2-CH2-,
• PO is independently at each instance O—CH2-CH(CH3)- or O—CH(CH3)-CH2-,
• BO is independently at each instance O—CH2-CH(CH2–CH3)- or O—CH(CH2–CH3)-CH2-,
• p1+p2+p3 is 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, or 75,
• and (meth)acrylic acid, comprising the steps of
• a) reacting the alkoxylated trimethylolpropane IIa with the (meth)acrylic acid in the presence of at least one esterification catalyst C, at least one polymerization inhibitor D, and optionally a water-azeotroping solvent E to form the ester F,
• b) optionally removing from the reaction mixture some or all of the water formed in a), during and/or after a),
• f) optionally neutralizing the reaction mixture,
• h) when a solvent E is used, optionally removing the solvent E by distillation, and/or
• i) stripping the reaction mixture with a gas which is inert under the reaction conditions, wherein
• a molar excess of (meth)acrylic acid to alkoxylated trimethylolpropane is at least 7.5:1, and
• the optionally neutralized (meth)acrylic acid present in the reaction mixture after the last process step substantially remains in the reaction mixture.