For examining the coating color and base paper interactions
A method for coating color optimization with the emtec PDA.C 02 - developed by G. Gruener and Dr. M. Baumeister
- Characterization of the coating base paper surface
- Defined coating color preparation
- Simulation of the coating machine applicators at the time the coating color and the base paper are contacted :
- Simulating the shearing history of the coating color in the coater
- Dynamically contacting the coating color with the base paper
- Producing a high shear impulse and pressure pulse
- Characterization of the coated paper
- Instantaneous measurement within approx. 39 msec after the contact
- Simple evaluation of the measuring results
What are the benefits of the measuring method?
- Differences in base papers, coating colors and coated papers lead to quality changes during processing; unfortunately, the classical measuring methods do not adequately detect these variations.
The PDA.C 02 system is able to identify these differences.
- Pilot coater and machine trials indicate the effects of coating color and base paper variations.
The PDA.C 02 provides a tool to explore the origins in the lab.
The PDA.C 02 can measure all three stages of the coating process :
1. Base paper
- Assessing process relevant surface quality parameters
such as surface porosity, surface sizing and fines/filler concentration at the surface
- R & D: Optimizing the base paper, developing new grades, ensuring quality consistency of several rolls in coating trials
- QC: Detecting slight quality variations during production
2. Coating color in contact with base paper
- Reducing the need for pilot coater / machine trials
- R & D: Visualizing the interactions between the coating and substrate surface, gaining new insights, optimizing the additive and pigment use (types and dosages)
- QC: Controlling the incoming quality of additives and pigments
- Assessing the changes in runnability, coating hold out, covering and print evenness in offset and flexo printing
3. Coated paper
- Assessing the surface quality of coated papers :
- Identifying small changes in the coating quality by comparing measurement results of liquid penetration with suitable test liquids (water, water + Isopropylalcohol mixture, acetic acid)
- Determining and predicting the properties such as printability, glueability or barrier effects on the basis of a database or process analysis
|R & D : Modelling of the processes and the coating color to base paper interactions|
|Characterizing the base paper by measuring with water and water + Isopropylalcohol mixture|
|Preparing and deaeration the coating color with a CDA / CDM laboratory system, taking the relaxation times after shear loads into account|
|Measuring the coating color to substrate interactions with the PDA.C 02 in the short term time range, simulating the coating machine applicators|
Evaluating the measuring results with the aid of the "Cookbook for coating color optimization":
Information is provided concerning the homogeneity, structure, thickness, density of the immobilized filter cake, runnability of the coating color, print evenness, coating hold out and covering.
A base paper sample is fixed on a sample holder and injected into a measuring cell with an adjustable measuring gap, filled with coating color. This causes dynamic contact between coating color and base paper, as well as a high-shear and pressure impulse.
Additionally, the penetration of other liquids into base paper or coated paper can be measured in a standard measuring cell, without the shear gap, applying the same measuring principle.
PDA.C 02 - Measuring Device
SFK Coating Color Measuring Cuvette
CDM Coating Color Deaeration and Mixing System
CDA Coating Color Deaeration System