REDUCTION OF THE SOFTWOOD LONG FIBRE PULP ADDITION IN TISSUE PRODUCTION. CASE STUDY

Abstract

The article summarizes properties of suspensions of six types of pulp used in production of tissue papers. Beating was performed on a laboratory device Jokro mill at the resulting 26°SR. The case study examined the effect of long and short fiber pulp and BCTMP on properties of the water suspension and on physical and mechanical properties of laboratory sheets of 70 g.m-2. Three different batches represent three specific combinations used in the selected production plant of the Metsä Group for tissue production. From the physical-mechanical properties the following parameters were evaluated: whiteness ISO (%), tensile strength (kN.m-1), stiffness (m.N), porosity Gurley (s), water absorption (%). The optimization defined the composition of: (1) batches for the production of toilet papers with lower whiteness and lower strength parameters at 30% Pine off 15 + 20% Pine off 20 + 30% AKI birch + 20% BCTMP, (2) batches for the production of toilet paper with high whiteness and high strength parameters at 30% RMA pine + 60% AKI birch + 10% BCTMP and (3) batches for the production of high quality kitchen towels at 20% RMA pine + 20% SCA black + 60% AKI birch. In the batch 1, for lower quality toilet paper, it was not possible to reduce the long fiber pulp content due to a low quality of Pine off 15 and Pine off 20. In the batch 2 for a higher quality toilet paper, this was reduced from 30% to 18% and in the batch 3 for the production of kitchen towels, the input of long fiber pulps has been reduced from 40% to 24%.