Kemira

Utilizing KemView™ sheet analyzer to optimize softness and control the creping process

There are different roads one can take to achieve tissue softness. The key is to be able to determine how to get there and when you are at your target destination.

Author: Kemira’s Clay Campbell, Lucyna Pawlowska, Xiaosong Huang

An easy and reliable measurement of sheet properties that determine softness will help to choose the most effective path and set a measurable sheet quality target. Paper manufacturers can utilize a variety of process tools to improve overall surface softness, formation and appearance. The most significant factor is the fiber type and ratios, followed by machine type and creping process configurations. Each process change impacts the sheet structure in positive or negative ways. The key to improving and maintaining final sheet softness is to measure how each process factor change impacts the sheet structure and then how each change in sheet structure impacts the softness.

 

Kemira combines best-in-class application expertise, latest technologies for smart process management and a complete chemistry portfolio.

 

KemView™ sheet structure analyzer (SSA) description/features

Kemira KemView™ SSA is an easy to use, fast response, sheet structure analyzer that provides a diverse array of sheet measurements and can be effectively used as a laboratory and field support tool assisting in the diagnostics of paper sheets. KemView™ consists of a digital optical detector positioned at the top of the unit. LED bulbs illuminate the sheet sample from 8 directions: one light at a time for FFE planar count and 4 light positions for crepe bar structure measurements.

We help customers improve their process efficiency, productivity and end-product quality

Kemira’s KemView™ SSA diverse features are beneficial for a new grade development, external product benchmarking, comparison of the same product manufactured on different machines, and troubleshooting sheet quality issues. It provides quick feedback allowing for optimization of creping, softening and strength programs. A variety of sheet surface properties can be measured by utilizing KemView™ and emtec Tissue Softness Analyzer (TSA).

Combined results from these two measurements provide a comprehensive insight into the sheet structure and softness, and allow for comparative analysis of various tissue products.

KemView is a novel image-based measurement tool that provides in depth 3D analysis of the sheet with the ability to easily measure the following parameters: crepe bar count (#/ inch); crepe bar width, length and height; crepe bar uniformity and distribution; embossing pattern; sheet roughness and intensity (crepe visibility); pinholes; number of free fiber ends (FFE).
Typically, a sheet structure that has a high crepe bar count and low crepe bars intensity (visibility) provide softer tissue. The higher free fiber ends count, the softer or more velvety hand feel surface.

 

Case study:

comparison of retail 2ply consumer facial tissue from four different manufacturers

Four consumer facial tissue products were tested for sheet strength, crepe structure, FFE’s & softness utilizing a tensile tester, KemView™ SSA, and emtec TSA.

Facial tissue #1
appears to be made on a TAD structured sheet machine, as indicated by sheet structure design, while the three other facial samples were made using a conventional dry crepe process. FFE count of facial tissue #1 may be low as a result of the structured sheet design.

Facial tissue #2
has a very high crepe bar count (101ct. in) and high sheet stretch.

Facial tissue #3
has poor surface smoothness, high crepe bars intensity and a very low crepe bar count. An increase in the crepe bar count and decrease in crepe bars intensity could increase TSA hand feel from 80.5 into the mid 80’s.

Facial tissue #4
had a very high FFE count and a relatively high crepe bar count, which contributes to tissue softness. However, both bulk softness and surface smoothness measured by TSA are not that great. In this case, selecting fiber of higher quality could improve softness.

Comparison of retail 2ply consumer facial tissue from four different manufacturers

TEST METHODS MEASUREMENT EFFECT ON SOFTNESS FACIAL #1 FACIAL #2 FACIAL #3 FACIAL #4
TSA HF – Hand feel Higher the better 88.8 85.3 80.5 78.7
TS 7000 Bulk softness Lower the better 8.8 9.6 10.5 11.7
TS 750 Surface smoothness Lower the better 7.2 9.7 15.2 13.8
D (mm/N) – Stiffness Higher the better 2.9 2.9 3.0 2.7
Sheet Properties Caliper 0.134 0.131 0.136 0.122
MD Tensile (gF/in) Lower the better 0.71 1.03 1.03 0.69
MD Stretch (%) Higher the better 14.6 32.1 24.5 23.4
MD TEA 0.067 0.171 0.119 0.082
KemView™ FFE – Velvety surface softness Higher the better 81 152 234 211
Crepe count (ct./inch) Higher the better 81 101 65 90
Intensity (%) Lower the better 0.43 0.59 1.21 0.78
Roughness (mm) Lower the better 0.0041 0.0021 0.0034 0.0027

 

Conclusions

There are many process factors effecting sheet softness.
Kemira’s Kemview™ SSA unique multi-functional portable measurement tool provides quantitative insight into the sheet structure, creping efficiency, free fiber ends, pinholes and overall sheet surface parameters that correlate well to sheet softness.

 

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