Greaseproof and Barrier Stocks for Fills That Defeat Plain Kraft
High-density refining and fluorine-free dispersion coatings block lipid migration and moisture breakdown where unrefined kraft papers fail under aggressive fills.
Pinhole Frequency ISO 16532
Defect Quantification
Standardized optical and chemical testing methods identify microscopic voids and discontinuities present in barrier coatings applied to paper substrates. Laboratory technicians measure pinhole frequency ISO 16532 to quantify surface defects that impair oil and grease resistance in coated paperboard. Test protocols apply dye solutions containing turpentine or surfactant mixtures onto the coated surface for specified durations.
Penetrated dye spots visible on the reverse side indicate coating defects and structural voids.
Permeation Detection
Coating defects stem from air entrapment, incomplete wet-out, or dewetting phenomena during barrier coating application. Microscopic pinholes act as capillary channels that allow grease and moisture vapor to bypass functional coating barriers. Test methods utilize grid templates placed beneath test specimens to systematically count and express defect density as pinhole count per square meter.
Low defect frequencies confirm continuous film coverage and uniform coating application across the web.
Quality Compliance
High speed packaging lines for greasy food products require consistent barrier paperboard to prevent package staining and contents degradation. Converting operations specify maximum allowable pinhole counts based on intended shelf life and product oil content. When testing reveals excessive defect density, mills adjust coating formulation parameters, coat weight, or drying profiles to eliminate micro-voids.
Quantifying pinhole frequency ISO 16532 provides paper mills and packaging converters with a standardized quality assurance metric for barrier coating integrity across commercial food packaging applications. Strict defect monitoring guarantees functional performance in demanding end-use greaseproof packaging markets.