Process for separation

The present invention relates a process for separation of the cellulosic part from a raw material composition comprising polyester and cellulose containing composition， wherein the process comprises providing a blend， wherein the blend comprises a raw material composition and a hydrolyzing liquor， wherein the raw material composition comprises a polyester composition， wherein the polyester composition comprises 99 %， or less， by weight of polyester and 1 %， or more， by weight of cellulose containing component or components， wherein the hydrolyzing liquor comprises a first mixture comprising an alkaline solution containing hydroxide ions， the hydrolyzing liquor is added to give the blend an effective alkali concentration in a range from 5 g/l to 150 g/l， wherein the effective alkali concentration is calculated as NaOH， and the hydrolyzing liquor: raw material composition ratio is from 1.5:1 up to 25:1 ， i.e. from 1.5 dm/kg up to 25 dm/kg， and keeping the blend at a temperature of 100 °C or above， e.g. 110 °C or above， for example， 115 °C or above， e.g. 120 °C or above， for example， 125 °C or above， e.g. 130 °C or above， for example， 135 °C or above， or， e.g. 140 °C or above; a cellulosic composition obtainable from the process for separation， a mixture comprising polyester hydrolysis products obtainable from the process for separation， a pulp， a dissolving pulp， a paper pulp， a regenerated cellulosic fibres product， and a paper product.