Abstract: Polymer, co-polymer and/or elastomer containing paper is manufactured for a wide variety of end uses. The paper is remarkably homogeneous and retains its porosity even when it contains large quantities of polymer, co-polymer or elastomer. The latex and the fibrous slurry are mixed at the wet end in conjunction with a polyelectrolyte bridging agent, the bridging agent having a cationic charge and the latex and fibrous material having an anionic charge. In this way, the latex particles in their substantially original size become linked with the fibrous material by means of the intermediate bridging agent and without the latex undergoing any substantially coagulation or precipitation.

Abstract: A new process for manufacturing sheets made of fibrous material containing latex is characterized in that the pulp containing the fibrous material is prepared in the following way:--adjustment of the pH between 4 and 5.5 and preferably between 4 and 4.5,--addition of an electrolyte, the polarity of which is of the opposite sign to that of the latex used,--addition of a foam inhibitor,--re-adjustment of the pH between 4 and 5.5, if necessary,--addition, preferably by injection, of latex,--second addition of an electrolyte having the same characteristics as indicated above,--possibly addition of resins (phenoplasts or aminoplasts),--re-adjustment of the pH to the previously indicated value, if necessary.The new sheets obtained by this process find use in the field of paper manufacture.