Polymers 2020 , 12 , 173
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the coating durability was evaluated by the degree of swelling and erosion [5], where the coating was immersed in distilled water at room temperature. After 24 h, the coating was filtered, the water residues were dried with filter paper and wet weighted, the sample was put in an oven (Memmert Gmbh + Co. KG, Buchenbach, Germany) for 24 h at 37 ◦ C. Its dry weight was recorded and the following Equation (2) was used for the calculation. %Erosion = (( W i − W f ) / ( W i )) × 100 (2) where W i is the wet weight and W f is the final dry weight. 2.3.2. Characterization of the Tissue Creping Paper The hand sheets for the analysis of the paper were obtained folding 16 times a 2.65 m 2 sheet of a paper roll which is then cut using an Alfa pneumatic precision cutter (Thwing-Albert Instruments Company, West Berlin, NJ, USA). As a result, 16 sheets whit 22.5 cm 2 area and grammage between 14.5 and 15.5 g / m 2 were obtained. Caliber of the 16 sheets was measured with a digital micrometer (testing machines Inc., Las Vegas, NV, USA). Tensile strength and elongation of 8 sheets in machine direction (MD) and 8 in cross machine direction (CD) were measured using a QC-1000 Tensile Tester (Thwing-Albert Instruments Company, West Berlin, NJ, USA). 2.4. Application of the Polycoat 38 ® and the Disprosol 17 ® in the Yankee Dryer Both products were added trough a shower at 35 psi using two dosing pumps, the Polycoat 38 and the Disprosol 17 ® where dosed with a 1.4:2 ratio to a 2.65 m wide and 5.2 m diameter yankee dryer working at a speed of 400 m / min, with internal steam pressure of 112 psi and an external temperature of 105 ◦ C, where the doctor creping blade exerts a pressure of 45 psi on the product which allows 14.5–15.5 g / m 2 grammage paper rolls with weights between 950–1150 kg to be produced at a speed of 336 m / min, leading to the fabrication of triple sheet towels in a Colombian toilet paper manufacturing company. Creping and cleaning blades wear were measured using a digital microscope camera (Microview Science and Technology Co., Ltd., Beijing, China). To complement the previous information, a graphical abstract of the methodology used from the coating synthesis to its application in the paper mill can be observed in the Figure 2.
Figure 2. Graphical abstract of the synthesis and application of the Polycoat 38 ® coating in the yankee dryer.
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