Preparation of pre-impregnate, useful for production of edging materials for doors, window frames and flooring, comprise impregnating paper with specific aqueous impregnating liquor

摘要

A pre-impregnate is prepared by impregnating a paper with an aqueous impregnating liquor, of a resin content 14-30 wt.%. The aqueous liquor comprises a melamine-formaldehyde precondensate, urea-formaldehyde precondensate, phenol-formaldehyde resin and a dry reinforcing agent based on an acrylamide/methacrylic acid copolymer and/or an acrylic acid ester/styrene copolymer. A pre-impregnate (I) is prepared by impregnating a paper of surface weight of 120-300 g/m<2> with an aqueous impregnating liquor (II) whereby the resin content is 14-30 wt.%. The aqueous liquor comprises a melamine-formaldehyde precondensate, a urea-formaldehyde precondensate, a phenol-formaldehyde resin, a dry reinforcing agent based on an acrylamide/methacrylic acid copolymer and/or an acrylic acid ester/styrene copolymer, optionally containing a dry reinforcing agent of a (meth)acrylamide/(meth)acrylic acid copolymer, whereby 1 weight part of a dry copolymer of (meth)acrylamide and (meth/acrylic acid is added to 0.3-13 weight parts of acrylic acid ester/styrene copolymer.