Curtain Coating Development Program
A typical conversion program follows these four steps.
1. Discussion of the Process Requirements and Feasibility
We need to know the target or range values for:
Coat weight
Speed
Starting solids level. If this contains a dispersed pigment we discuss ways to maximize solids level
We will calculate the required flow rate from the die. This is usually expressed in gm/cm/sec. At this point we can discuss the kinds of things required to make the formulation work. We’ll want to know about chemistries we can use or not use to adjust surface tension and rheology. There is no charge for this discussion.
Surface tension and rheology is important. Generally the process starts at 35 dynes/cm.
Water is 72. 35 will run at 1.5 gm/cm/sec. 30 dynes/cm/sec with the right rheology will allow 0.7 gm/cm/sec to run. Lower flow rates are possible in some cases.
2. Coating Evaluation in our lab.
Predict the as received coating’s coat weight and speed window using Stretch Tester data.
Modify this coating with additives until it will run at the target conditions.
One gallon of coating is required.
Provide samples of the modified coating for your end use evaluation.
3. Coat Lab Samples
We can coat 5” by 10 foot long sheets on our lab curtain coater. These will be coated at process speeds and dried with a lab oven.
We can coat 5 to 15 sheets a day depending on the formulation changes.
It is efficient to make a range of coat weight samples by varying the speed and keeping the die flow the same.
4. Commercial Qualification Trials
We co-operate with Faustel for pilot coater trial work.
We can coat 24” width on any line.
You are welcome to send 1 or 2 people to any of the trial work. This will increase the trial productivity, foment discussion, improve your understanding of the technology, and allow you to change the trial plan as results come in.
We look forward to working with you.