Roll-to-Roll Coating Operations in a Clean Room

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1 AIMCAL Fall Technical Conference October 7-10, 2007 Scottsdale, AZ Dr. Kenneth McCarthy Sr. Product Development Eng. Manager Multilayer Coating Technologies, LLC 100 Duchaine Boulevard New Bedford, MA (W), (C)

2 Outline Product performance What s acceptable? Fluid Preparation Filtration Base Cleaning Cleanliness Level Measurements Control of Static Operational Considerations Cleaning Procedures What s really important

3 Product Performance What s Acceptable? Product requirements are essential Operate so that product requirements are met all the time Balance between meeting and exceeding is necessary

4 Fluid Preparation Good fluid preparation is vital Need full dissolution for solutions Need excellent dispersions for particulates Bubbles are a killer

5 Filtration Sources of Information Filter Technology Filter Pore Size

6 Filtration Books (Cohen & Gutoff, filter catalogs) Stages For heavy duty filtration requirements, it often works well to have a coarse filter to remove 80-90% of the larger debris, followed by a polishing filter to bring the fluid to the desired level of cleanliness.

7 Filtration

8 Filtration Smaller pores are not better Pressure drop Capacity issues Removing gels Forming gels

9 Outline Product performance What s acceptable? Fluid Preparation Filtration Base Cleaning Cleanliness Level Measurements Control of Static Operational Considerations Cleaning Procedures What s really important

10 Base Cleaning Covered in next talk Several technologies available, but Get base from vendor as clean as possible

11 Cleanliness Level Measurement Classification numbers How, when, where to measure Counter Example

12 Cleanliness Level Measurements What do the numbers mean? Class 100,000 10,000 1, >0.5 u >5 u No more than 100, , ,

13 Cleanliness Level Measurement Several commercial counters available Values measured at rest no activity If have HEPA or ULPA filter bank for incoming air, check each filter unit at least once/year Check several points in the process Check people in clean room suits Check dryer air

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15 Control of Static How static is generated Problems with static Measurement of static Control of static

16 Static Generation Static charges generated any time two materials separate Amount of charge remaining depends on conductance of material surface Static charges are not good for coating in a clean room

17 Problems with Static Many substrates used in coating are excellent dielectrics, eg., PET As such, they can hold large amounts of charge Measured potentials of 10-20,000 volts are common Charges in this range attract particulates Oil droplets can be pulled from 1-2 feet away from the substrate

18 Measurement of Static Need to know where you are Buy or rent a static meter Measure levels throughout the machine Changes in speed or substrate can change static levels

19 Control of Static Change materials difficult to do Substrate with an antistat added or coated Most effective, but more cost May not be compatible with product Add static control measures Humidity control Static brushes or wires Ionized air Ionizing sources, eg., Americium bars, with safety first

20 Outline Product performance What s acceptable? Fluid Preparation Filtration Base Cleaning Cleanliness Level Measurements Control of Static Operational Considerations Cleaning Procedures What s really important

21 Operational Considerations People Air flows Materials delivery Records

22 People The human body is an exquisite thing but not in a clean room People generate particulates at the following rates: Standing 100,000 particles/minute Walking slowly 5,000,000 particles/minute Vigorous activity 100,000,000 particles/minute Clean room suits are essential, even beard masks

23 Air Flows Positive pressure in the coating area is necessary Laminar flow key to keeping large particles out of the air stream Dryers isolated as much as possible

24 Materials Delivery Roll packaging materials lots of particulate possibilities: remove outside clean room Vacuum rolls before entry Deliver rolls through a lock if possible Minimize any other materials Roll cores are often overlooked

25 Records Try to not have any in the clean area Use computers or terminals to record information Use clean room paper if need written records Overlaminate diagrams, procedures, and protocols

26 Cleaning Procedures Clean floor and horizontal surfaces frequently, at least weekly Minimize cleaning residues Water best to finish Care here pays off in product quality

27 What s Really Important?

28 Actual Case Mystery Contaminant

29 Contamination Losses 7 6 % Lost A-shift B-shift C-shift

30 Contamination Occurrence Defect Frequency Time

31 Problem Solving Techniques Kepner Tregoe Cause and Effect Diagram Failure Mode Effect Analysis OOTF: Out on the Floor

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35 What s Really Important? Good equipment Good protocols Good training Pay attention to details

36 Outline Product performance What s acceptable? Fluid Preparation Filtration Base Cleaning Cleanliness Level Measurements Control of Static Operational Considerations Cleaning Procedures What s really important