3b are transferred to a hydropulper 5 in which a foamed aqueous dispersion of glass fibres 6 has previously been formed because of the homogeneous mixing which has previously taken place in the mixer 1 the homogeneity of the dispersion of fibres and particles thus formed in the hydropulper 5 is assured furthermore substantially all of the powdered pigment 4 continues to adhere to the larger polymeric particles 3a and 3b as best seen in microdiagram 7 the foamed aqueous dispersion formed in the hydropulper 5 is then used in the formation of a wet laid web in the process 8 which is carried out according to the process described in the aforementioned european patent application the resulting web comprises well distributed glass fibres and polymeric particles with the polymeric particles still retaining adherent pigments as best seen in microdiagram 9 the formed web is then passed to drying pressing and moulding stages 10 as required which do not form part of this invention if the two particulate polymers 3a and 3b and the pigment 4 are added directly to the hydropulper 5 as indicated by the broken lines 11 and not premixed in a substantially dry state in the mixer 1 it is more difficult to achieve homogeneous mixing with the fibres 6 in the dispersion furthermore the powdered pigment becomes dispersed as individual particles in the foamed dispersion as best seen in microdiagram 12 as a result they tend to be lost in drainage during the wet laying process so that few or none remain in the formed web as shown in microdiagram 14 it will be appreciated that.