초록 ▼

An exothermic gel polymerization process conducted in the presence of water is initiated at a low temperature, is held for most of the process at a higher temperature by including in the medium a particulate heat sink material, such as sodium sulphate decahydrate, that is substantially insoluble in

An exothermic gel polymerization process conducted in the presence of water is initiated at a low temperature, is held for most of the process at a higher temperature by including in the medium a particulate heat sink material, such as sodium sulphate decahydrate, that is substantially insoluble in the medium and which undergoes an endothermic phase change and is then allowed to rise to a higher temperature. Either as a result of the endothermic change, or as a result of a subsequent exothermic change, at the end of the process the heat sink material is again solid particulate material substantially insoluble in the medium and so the product is a dispersion of the material in a polymer gel. The polymer is water soluble.

대표청구항 ▼

A bulk gel polymerization process for producing a water soluble polymer by exothermic bulk gel polymerisation of a reaction mixture that comprises 100 parts polymerisable monoethylenically unsaturated monomers dissolved in 33 to 250 parts added free water and that contains a heat sink material that

A bulk gel polymerization process for producing a water soluble polymer by exothermic bulk gel polymerisation of a reaction mixture that comprises 100 parts polymerisable monoethylenically unsaturated monomers dissolved in 33 to 250 parts added free water and that contains a heat sink material that is in a first thermodynamic state, is particulate and is substantially insoluble in the reaction mixture, in which the polymerisation reaction is initiated at a temperature T1 at which the heat sink material remains in its first thermodynamic state, the temperature of the reaction mixture rises exothermically to T2 at which the heat sink material undergoes an endothermic change of state to a second thermodynamic state by absorbing the exothermic heat of polymerisation and the amount of heat sink material is such that when the all the heat sink material is in the second thermodynamic state, the temperature rises exothermically to T3, and in which the process includes the step of converting the heat sink material from the first thermodynamic state to a final thermodynamic state in which it is particulate and substantially insoluble in liquid medium.