Kitchen Towel Surface Characterization
SCA Research AB approached Lucideon (which was at the time called Ceram) regarding a project to optimize performance of the Proctor & Gamble product, Bounty kitchen towel. They wanted to determine the rate of uptake for a given process loading of the wet strength additive together with its spatial distribution relative to the fibre disposition within the paper construction.
What We Delivered
A series of tissue papers were prepared using different concentrations of wet strength additive (PAE - polyamide epichlorohydrin). Using secondary ion mass spectrometry (SIMS) the degree of uptake of the PAE on the tissue surfaces was measured from the secondary ion counts generated. By detecting different secondary ion species characteristic of PAE (CN-) and cellulose (C2H-) a ratio expression was generated which gave a quantitative measure of the PAE uptake at three different treatment loadings and in comparison with a commercial sample - see figure 1.
The distribution of the wet strength additive relative to the cellulose fibre disposition was then determined using SIMS in imaging mode. Again, the characteristic ion species were used to determine the location of the PAE relative to the fibre structure. These are ‘false’ coloured in figure 2 with the PAE in red and the fibres in cyan. It is clear that the PAE accumulates at the fibre cross-over points preferentially. This had long been suspected but never proven definitively.
To establish the relative concentrations in the crossover points (Cr1, Cr2) relative to the fibre outer surfaces (F1, F2) small area SIMS analysis was conducted in the labelled areas in figure 3. This showed a three-fold increase in the cross-over areas.
Value to the Client
The client was able to demonstrate additive effectiveness which strengthened the product claims in promotional material. The quantification of the relationship between PAE uptake and process loading enabled optimization of the production process ensuring the minimum amount of additive was used for maximum product performance.