Flexographic Aqueous Latex Barrier Coating Viscosity Measurement Fundamentals
Flexographic aqueous latex barrier coating viscosity requires multi-shear rotational measurement to ensure accurate anilox transfer and barrier film continuity.
Iso 2431
International Standard
Documented testing protocols developed by the International Organization for Standardization establish the reference method for measuring the flow time of paints, varnishes, and related coatings using flow cups. The framework of iso 2431 specifies the exact dimensions and tolerances for cups with orifices ranging from three millimetres to six millimetres in diameter. This protocol is the global benchmark used by packaging printers to calibrate the viscosity of liquid materials before application.
Technical Specification
Every conforming cup must be made from high-grade corrosion resistant material with a highly polished interior surface to prevent turbulence during drainage. The standard defines the relationship between the drainage time and kinematic viscosity, prohibiting the use of these cups if the flow time falls below thirty seconds or exceeds one hundred seconds. This limitation ensures that the fluid flow remains laminar, which is necessary for accurate and repeatable measurements.
Correct temperature management is mandated, requiring tests to be conducted at twenty degrees Celsius unless otherwise agreed.
Quality Compliance
Ink and lacquer suppliers formulate their products to match these standard viscosity curves to ensure consistent delivery on the gravure or flexographic printing press. When paperboard is coated, maintaining the flow time within the limits defined by this standard guarantees that the applied layer is neither too thin to protect nor too thick to dry properly. This testing procedure helps mills and converters avoid coating defects and reduce waste on high-speed production lines.