Pick strength

The application properties of many latexes are strongly affected by the chemistry of the surface of the polymer particles. Relatively small amounts (1-2 wt% based on monomers) of acidic monomers (e.g., acrylic acid, AA) are frequently used in the manufacture of latexes. Because this monomer is water-soluble, upon polymerization, most of the AA-rich polymer chains are located at the surface of the polymer particles. The presence of AA at the surface of the polymer particles is beneficial for both the stability of the latex [11] and the application properties (e.g., both the shear strength of the adhesives [ 12] and the pick strength of coated paper [9] increase with the AA content). In addition, the type and amount of surfactant affects application properties such as colloidal stability and water sensitivity of the film [13]. 

In rotogravure printing, the tensile forces between the printing cylinder and the surface of the paper are very small, as solvent-containing, low viscous inks are used. So rotogravure printing requires only very Htde pick strength of the paper... 

Water resistance or wet pick strength Print gloss... 

Binding strength (pick strength) Medium high High-very high... 

The rotogravure process uses inks with a very low viscosity. It therefore has the lowest requirements in terms of the pick strength of the paper. To guarantee the even and error-free transfer of the printing inks (i.e. low number of missing dots) from the rotogravure cells to the paper, requires paper which is both smooth and compressible. 

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.

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