Wet pick strength

Water resistance or wet pick strength Print gloss... 

In contrast to the other possible monomer components, butadiene possesses two double bonds both of which can act as polymerization sites. Binders based on a styrene-butadiene combination therefore have a more cross-linked and branched polymer structure. The extent of cross-linking affects the dry and wet pick strength, the print gloss and the degree of blistering, which is a highly significant parameter in... 

Wet pick strength of paper and board coatings improves with decreasing particie size... 

Fig. 4-17 Dependence of the wet pick strength of binder dispersions on particle size.

Starches used to increase the internal strength of paper as measured by tensile, edge cmsh resistance, Mullen burst, and Scott bond strength are added at the wet end, whereas starch used to increase surface strength as measured by pick and resistance to Hnting are added at the size press. 

An alternative method to apply starch to paper, especially to paperboard grades, is to use a water box at the calender. Water boxes are used for wet-finishing of paper-board prior to coating application. Use of starch in the water box will increase surface strength and lessen fiber reswelling after coating application. Dilute dispersions of oxidized starch are used, frequently in conjunction with a lubricant to prevent calender roll picking. 

Application of mechanical work to the adhesive-metal interface (by adhesive flow through the gap between the dollies at various speeds) had greater effect on the adhesion strength when cementing was performed in the liquids than in the air (see Fig. 5.2). This can be explained by the fact that the work done facihtates the selective wetting of the substrate by the adhesive the flowing adhesive picks up drops of liquid from the substance surface and removes them. 

Chemical compounds which contain reactive groups such as the methanol group (-CH2OH) as in methanolamine compounds are able to form stable, covalent bonds with cellulose fibres. This treatment decreases the moisture pick-up and increases the wet strength of reinforced plastics. Isocyanates are also suitable to modify the chemical structure via its reaction with the OH groups of cellulose. The mechanical properties of composites reinforced with wood-fibre and PVC or PS can be improved by an isocyanate treatment of those cellulose fibres or the polymer matrix. The improvement of the properties of the composites can be explained by the reduction in the number of OH groups responsible for moisture uptake and consequently the increase in the hydrophobicity of the fibre s surface... 

---