with urea phenol resorcinol melamine or mixtures thereof of these the formaldehyde urea binder base is preferred the binder base contains a binder modifying amount of a styrene acrylic resin containing a polyfunctional component which crosslinks with the copolymer resin during curing of the mat the styrene component of the resin can be unsubstituted or substituted on a ring carbon atom with lower alkyl vinyl allyl chloro or phenyl however from the standpoint of economics notwithstanding the reduced flammability and high thermal stability of some of these substituted types unsubstituted styrene is most desired the styrene acrylic resin which includes both acrylic and methacrylic moieties and mixtures thereof contains a minor amount e g between about 0 05 to 10 wt preferably between about 0 1 and about 5 wt of a crosslinking agent which may be a nitrogen containing crosslinking agent such as a polyfunctional amine amide or acrylonitrile or may be any other polyfunctional crosslinking agent such as for example a di or tri olefinically unsaturated hydrocarbon or other conventional crosslinker reactive with the styrene acrylic copolymer of the above polymer compositions those providing self crosslinkable characteristics are preferred the meth acrylic polymer is generally a mixture of meth acrylates and additionally may contain.