How To Select The Coater For Your Needs

In today's industry, there are numerous coater configurations and an infinite number of coating formulations. How does the converter or equipment supplier determine the appropriate combination of coater type to coating formulation? 

There are always several possible combinations. The objective is to choose the right combination to cover all or most of your needs as cost effectively as possible. To make this decision, several properties are evaluated for each formulation and coater selection. These criteria are: 

Coatweight is the amount of a coating formulation that is applied to the substrate. The functionality of the end product dictates the amount of coating needed. The solids of the coating depict the amount of wet coating that is applied to the substrate. This is calculated by: 

Dry coatweight (#/Ream) 
Percent Solids 		 = Wet Coatweight (#/Ream)
 
Wet coatweight (#/Ream) 
Density (#/gal.) 		 = Thickness (mils.)


The viscosity can be measured with several different methods. One method utilizes a Zahn Cup that has a hole in the bottom. It is filled with coating, as the time it takes to empty the hole is measured. This time is referenced to a chart that determines viscosity. A Brookfield Viscometer that measures resistance may also be used to determine viscosity. Shear stability can be measured with a more precise type of rotating bob machine, known as a Hercules High Shear Viscometer.  

Surface tension is important when the coating is water or solvent based. The surface tension of the coating and the substrate must be close or dewetting may occur. Some coaters can alter the surface tension of the coating during the application process. Corona or flame treaters may also be utilized to affect the surface tension of the substrates. 

The end use of the product determines the functionality and/or appearance that must be achieved. To achieve this goal, coating criteria can be altered chemically or mechanically. 

When all the criteria has been identified, then the coater selection can be addressed. A Black Clawson "Coater Application and Selection Guide"that cross-references some coating properties with the coater properties is located on the back of this sheet. Find the coating on the left that meets your requirements and look for an X on the right. At the top of that column, there is a coater that could be a match for your process. Under the coaters at the top are four operating parameters for each coater.

CLICK HERE to download "Coater Cheat Sheet"
Questions?  Call Black Clawson Converting Machinery at 315-598-7121 or e-mail us at bc@bc-egan.com

BC Publications is a technical newsletter designed to provide operational and maintenance information to improve the performance of your Black Clawson equipment.