White Powder Exist in Surface of Polyethylene Film

I have a problem regarding my product Polyethylene Film. There is white powder in surface film, but not clearly seen, if I use black napkin to swab the film, the napkin turns to vivid white. My product is endless film without printing and using Blowing production method. I am afraid this will affect to food safety because most of my customer is food industry.

If you have any idea what root cause which made that white powder, please give me advice, what could I do, maybe what test I should do to identify this powder.

Thank you

Did you try contacting the supplier for a product spec sheet/product analysis or asking them if they use some sort of 'non-stick' additive?

for example: We use plastic film to produce thermoformed plastic packaging and all films are coated with food grade silicone in order to make the material manageable during molding. This leaves a grey residue on equipment which we have to clean periodically, still the material is approved by the FDA/CFIA/EU for use in direct contact food packaging material.

Never had this issue with PE (we have PE in liner bag and plastic film for thermoforming)..maybe you got a bad batch?

Ask them what type of additives they have in their product. This is where I would start, then if you cannot get an answer you can try a chemical analysis lab and they should be able to help you with this.

Best of luck to you.

Kindest Regards,

Danica

• You can try running test for Unknown contamination. Also, have you tried auditing your production/storage area? Is there any repair or upgrade happening in the facility? What is the PM schedule for your machine? I hope this gives you ideas of what to look into.

Thank you.

As Danica said, the issue probably lays on the co-materials. They may be residual catalysts in the premature fabrication, enhancers for applications (molding, inflation) such as viscosity control, additive for later storing (anti-blocking after rolling film, anti-slipping to reduce friction), additive for customer's usage (white pigment as light barrier), etc. The problem is the compatibility of those additional materials with PE matrix. When they have poor compatibility, their particles aren't well dispersed or dissolved within the PE matrix and they eventually diffuse/migrate to the film surface.

Beside that, wrong mixture ratios (by you or suppliers) can make the same phenomenon, due to the over-saturation and solubility.

Hope you can use these as inputs.

I don't have answers but my first 2 questions may help.

1. Can the film manufacturer explain or do some testing for you to prove their material is safe?

2. Is there a static electric issue pulling something from the air or room it is being used in?

It could be the result of corona treating the film (corona dust = small particles of the film).  It could be a slip agent that is blooming to the surface.  It could be a dusting that the supplier uses to control the slip.  You need to contact your supplier

Possibly oxidry ( known in the industry as food grade starch) used to remove static from  film; If this is the cause, then the use of oxidry is not the fix ? The raw material film supplier needs to work on a permanent fix to reduce static from the film.

The white powder is probably the slip agent that bloom o the surface, it is oleamide or Erucamide, depends on which type is being used by the resin producer.

How long have you had the bags, or the film?  The longer you keep them, the blooming is worse.

Check if the resin used comply with 21CFR155.1720, for direct food contact application.

I have a problem regarding my product Polyethylene Film. There is white powder in surface film, but not clearly seen, if I use black napkin to swab the film, the napkin turns to vivid white. My product is endless film without printing and using Blowing production method. I am afraid this will affect to food safety because most of my customer is food industry.

 

If you have any idea what root cause which made that white powder, please give me advice, what could I do, maybe what test I should do to identify this powder.

 

Thank you

For sheet in roll production,  look at the thickness of the film, the slip agent content, how many ppm?

The thinner the film, the slip content should be higher, thicker film will require less slip agent content,

It is done through the blend of different material grades , or the slip additive is added.

Is the film LD rich or LL rich?

C4 material can give you this problem too,  it is lesser with C8 and above.

Corona treatment can increase the blooming effect too.

I have a problem regarding my product Polyethylene Film. There is white powder in surface film, but not clearly seen, if I use black napkin to swab the film, the napkin turns to vivid white. My product is endless film without printing and using Blowing production method. I am afraid this will affect to food safety because most of my customer is food industry.

 

If you have any idea what root cause which made that white powder, please give me advice, what could I do, maybe what test I should do to identify this powder.

 

Thank you