Composiciones poliméricas que contienen fosfatos

Una composición polimérica, que comprende: (i) uno o más polímeros de múltiples etapas, que comprenden (a) un polímero de primera etapa con una Tg de 0ºC o inferior, (b) un polímero de subsiguiente etapa con una Tg de 20ºC o superior, (ii) una o más sales de fosfato de un catión multivalente, en que el anión de dicha sal de fosfato de un catión multivalente consiste en átomos de fósforo y oxígeno, y (iii) uno o más fosfatos alcalinos, en una cantidad de 100 ppm o más, medida según el peso del fósforo, basado en el peso en seco de dicho polímero de múltiples etapas, en que el fosfato alcalino es una sal de un catión de metal alcalino con un anión fosfato que consiste en átomos de fósforo y oxígeno, o una sal parcialmente neutralizada de un ácido de fosfato. In a first aspect of the present invention, there is provided a polymer composition comprising (i) one or more multistage polymer comprising (a) a first stage polymer having Tg of 0°C or lower, (b) a subsequent stage polymer having Tg of 20°C or higher, (ii) one or more phosphate salt of a multivalent cation, and (iii) one or more alkaline phosphate, in the amount of 100 ppm or more, measured as the weight of phosphorous, based on the dry weight of said multistage polymer. In a second aspect of the present invention, there is provided a mixture comprising the polymer composition of the first aspect described above and one or more matrix resin. In a third aspect of the present invention, there is provided a process for making a polymer composition comprising the steps of providing a multistage polymer latex, coagulating said multistage polymer latex, mixing said multistage polymer with an aqueous solution of an alkaline phosphate, and drying said multistage polymer to a water content of less than 1% by weight of water based on the dry weight of said multistage polymer, wherein said dried multistage polymer comprises 100 ppm or more, based on the dry weight of said multistage polymer, of phosphorous that is in the form of an alkaline phosphate.