Process for producing an absorbent core containing an upper substrate layer, a lower substrate layer and an absorption layer arranged between the upper and the lower substrate layers, wherein the absorption layer comprises a particulate absorbent polymer material and less than 0.1 g of cellulose fibres per gram of particulate absorbent polymer material, containing the process steps of: A) providing a particulate absorbent polymer material; B) incorporating the particulate absorbent material in an absorbent core; wherein the particulate absorbent polymer material provided has the following properties: i) a maximum APC i × 10 sec value ≥ 1.6 for at least one number i selected from the group of integers from 2 to 12 (= APC max value); ii) a value ≥ 12 for the sum total of all APC i × 10 sec values for all numbers i from the group of integers from 2 to 12 (= APC sum value); wherein the APC i × 10 sec value is defined as follows: APC i × 10 sec value = QI i × 10 sec value 2 × PI i × 10 sec value where - the QI i × 10 sec value is the value of the swell index determined as per the herein described test method i × 10 seconds after adding the 0.9% by weight NaCl solution, and - the PI i × 10 sec value is the value of the permeability index determined as per the herein described test method i × 10 seconds after adding the 0.9% by weight NaCl solution; characterized in that the particulate absorbent polymer material is provided by: selecting a suitable particulate absorbent polymer material on the basis of the results of determining the product of (swell index) 2 and (permeability index) (= APC value) for at least one time t i after adding a fluid to the particulate absorbent polymer structure; where the product of swell index 2 and permeability index (= APC value) is determined for at least 11 different times t i and the particulate absorbent polymer material is selected on the basis of the sum total of all APC values obtained. A) providing a particulate absorbent polymer material; B) incorporating the particulate absorbent material in an absorbent core; i) a maximum APC i × 10 sec value ≥ 1.6 for at least one number i selected from the group of integers from 2 to 12 (= APC max value); ii) a value ≥ 12 for the sum total of all APC i × 10 sec values for all numbers i from the group of integers from 2 to 12 (= APC sum value); - the QI i × 10 sec value is the value of the swell index determined as per the herein described test method i × 10 seconds after adding the 0.9% by weight NaCl solution, and - the PI i × 10 sec value is the value of the permeability index determined as per the herein described test method i × 10 seconds after adding the 0.9% by weight NaCl solution; selecting a suitable particulate absorbent polymer material on the basis of the results of determining the product of (swell index) 2 and (permeability index) (= APC value) for at least one time t i after adding a fluid to the particulate absorbent polymer structure; where the product of swell index 2 and permeability index (= APC value) is determined for at least 11 different times t i and the particulate absorbent polymer material is selected on the basis of the sum total of all APC values obtained.