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Comments

[vikas aggarwal]

Does the temperature gained on the surface of the BOPP film after metallising ,cause a rapid reduction in treatment? Is it necessary to have a minimum dyne level of 36 on metallised BOPP to laminate it to polyester?

[dave wilson]

How does a perm rating differ or compare to MVTR. If a customer asks for a perm rating of .02, can I convert this to an MVTR rate?

Thanks,

Dave Wilson

[Mark McGarel]

On multiple passes through the metallizer we notice various levels of oxidation on the metallized(aluminum) side of 92 gauge PET film. There appears to be little oxidation after the first pass but significant oxidation after the second. The amount of metal is a target of 2.5 optical density for each pass.
Is there a way to measure the oxidation? Is there a way to control the amount of oxidation that occurs? Can it be eliminated from the web prior to lamination?

regards;

Mark McGarel - FILMtech Inc.

[S. Levesque]

Question concerning the barrier measurement vs sampling position in a slit roll.

We metallized OPP in Aluminium deposit chamber and I observed a variation in WVTR and OTR data with sampling position in the slit roll :

1. Why barrier seems to be better more deeper in the roll than near the surface ?

2. Where is the best location to take a representative sample : on the roll "out-of-chamber" or on the slit roll ?

Thanks.

SL

[CH]

During our normal maintenance of our vacuum chamber, we recently open two of the diffusion pumps, the maintenance people notice a heavy critallized deposit at the top part of both pump. It's something we never had observed in the past. The cristallized deposit is white and oily. If you applied heat to it, it liquify.

Have you ever heard of something similar ? If yes, what can cause it ?

Thanks,

CH

[Alan Newington]

What is the polymer used to coat a plastic to improve the surface to an optical reflecting standard for aluminium vacuum depositing. Where would we be able to obtain the polymer.

Thank you

[Phil Davies]

Can you help me understand how a RGA leak tester works. and if this is a outdated system?

[Claire Poirier]

How would you measure in-line the thickness of a PVD coating (knowing its optical characteristics)? Is it possible for a roll to roll process? Do you need to have a stable distance between detector and coil? Do you know people who do that?

Thanks,

[Victor de Legarreta]

A new product requires to metallize on homopolymer polypropylene. We have tried with both corona and flame treated homopolymer, but we do not get good adhesion. of course, this film has no additives thay may harm.
Would it work with vacuum plasma? Please explain what is happening and suggest something.

[Eldridge M Mount III]

In the metallization of homopolymer surfaces it has always been difficult to obtain a high level of metal adhesion (i.e. low % metal lift on peeling). In general it is more difficult to treat the homopolymer polypropylene without degrading the polymer surface due to polypropylenes increased tendency to chain scission especially relative to polyethylene. It is more difficult to obtain “high treatment” numbers with homopolymer polypropylene so the tendency is to increase the treatment power, either watts or gas/air flow rate, for corona and flame respectively. However, this simply over treats and degrades the film surface creating a weak boundary layer which is the ultimate source of the low bond strength. So before you abandon the corona and flame completely I would lower the treatment levels and determine the optimum for adhesion as distinct from wetting. Generally, I would prefer flame treatment to corona due to the chemistry of the surface treatment and the absence of back side treatment.

In-chamber Plasma treatment does appear to improve the bonding of aluminum to homopolymer polypropylene perhaps because it captures the treated sites before they have time to degrade, but this is not known with any certainty. Generally, you will need to combine the online and in chamber treatment processes together to optimize the performance of the metal layer. So lower the on line treatment and add in chamber plasma treatment and optimize the combination to optimize the films metal adhesion performance

[Eldridge M Mount III]

Does the temperature gained on the surface of the BOPP film after metallising ,cause a rapid reduction in treatment? Is it necessary to have a minimum dyne level of 36 on metallised BOPP to laminate it to polyester?

In general, the surface energy of the aluminum surface is high and stays high if kept clean and free of contamination. Decreases in aluminum surface energy are due to transfer of additives from the unmetallized OPP surface to the metal surface while wound in the roll. Because the bloom of additives to the surface of OPP films is driven by heat, I would assume that warmer rolls exiting the metallizer may indeed accelerate the bloom and transfer of additives from the OPP film. However, it is the total thermal history during storage and transport to the customer which will affect the time to contaminate the metal surface. In order to have consistent adhesive lamination bonds it is always best to prime the metal surface to obtain the best adhesive bond when using OPP. However the adhesive must wet the aluminum surface and in order to insure the best most uniform wetting of the primer, the metal surface should be treated to "burn off" the additive tuypically with a bare roll corona treater, being careful not to hurt the heat sealing layer in the process (treatment of copolymer surfaces will increase the minimum sealing temperature so be careful not to have any back side treatment when cleaning the metal surface with a corona. The minimum dyne level will depend on the cleanlyness of the metal surface and the contamination level. I would always retreat the metal prior to priming to obtain the most consistant bonds

[Shaheen]

I am a student attending the University of Waterloo. I am now on my work term working for a company producing BOPP.

This company has a plasma treatment unit (in a vacuum)(within a metallizer [for 250 cm rolls]) that does not function well. Due to some software problems, we can only restrict the Plasma Power up to around 2kW (maximum when fixed: around 11kW). Plasma Power exceeding around 2.5kW will cause the arc value to increase signifcantly (which is undesireable).

My job is to optimize the effectivness of plasma treatment (in a vacuum) process with a constant gas composition being of 80% Argon and 20% oxygen (in one cylinder). Are the only other parameters from which I can alter, record and graph against optical density, OTR, and WVTR values :

>gas flow rate
>plasma power (within the limit)
>vacuum level (If so, how will it effect the process?)

Moreover, to test for the effect of the plasma treatment process, what properties, other than optical density, OTR, and WVTR can we measure to get QUANTATIVE results?

Any other tips??
Please advise.

Thank you

[Shaheen]

Hello;

Can you kindly advise the different methods of surface treatment we can use for treating BOPP film (e.g.: flame treatment, plasma treatment in vacuum....)?
What are the advantages and disadvantages of each of the treatments? At the right conditions (can you pls also advise the conditions), what is the rate of improvement for different plasma powers, gas flow rates, and web speeds when we compare it with no
plasma treatment BOPP film

Thank you in advance for yr help

Regards
Shaheen Zangooi

[Shaheen]

Hello;

Can you kindly advise the different methods of surface treatment we can use for treating BOPP film (e.g.: flame treatment, plasma treatment in vacuum....)?
What are the advantages and disadvantages of each of the treatments? At the right conditions (can you pls also advise the conditions), what is the rate of improvement for different plasma powers, gas flow rates, and web speeds when we compare it with no
plasma treatment BOPP film

Thank you in advance for yr help

Regards
Shaheen Zangooi

[szangooi]

1)What do we try to achieve with plasma treatment (in vacuum) on BOPP film.

2)How is BOPP film effected when treated by plasma treatment in vacuum. In other words, how is the structure of the surface altered.

3)If there are any disadvantages of plasma treatment (in vacuum) what are they?

Thanks.

[Ghelghelloo]

1)What is the 'Plasma Theory'?
2)What is the background of low pressure (vacuum) plasma treatment plasma surface treatment?
3)After corona treatment of BOPP film, why is it required to further treat the film by low pressure (vacuum)plasma treatment?

Thanks

[Charles A. Bishop]

Hi, relating to the questions you posed to the VacuumCoatingBlog.

Have you read the posting of 13th Feb about treating surfaces?
This posting explains some of what you are wishing to know.

For vacuum web plasma treatment the pressure used can have a wide range depending on the plasma treater used and the position the treater is placed in. In some systems the unit is placed in the winding zone and with some gas introduction this makes the pressure quite high. Whereas in other systems the unit is positioned in the deposition zone and so the background pressure is 1 x 10E-5 Torr. The pressure in the unit is often at least a couple of orders of magnitude greater than this. This too can have a wide range of pressure depending on the design of the plasma treater and if it has magnetic confinement how strong the magnets are.


Regarding corona treatment. Good corona treatment that is metallized soon after treatment may well be acceptable in most instances. However for some products it may not be good enough or in other cases if the metallization is delayed there is the possibility that the surface degrades with time or is recontaminated from slip agents or other additives that are used to make give some of the mechanical properties as well as to make the polymer web handlable. In this case either the corona treatment needs to be re-done or the web needs to be vacuum plasma treated.
Often the corona treatment is only done on one side & so the reverse side has all the contaminants left in place and as soon as the polymer web is wound up the back surface will come in contact with the front surface and start to re-contaminate the front surface.
In vacuum plasma treatment the cleaning process is done immediately before the metal deposition & so there is the minimum chance of re-contaminating the surface & so if the vacuum plasma treatment has been done to the correct level this will lead to the optimum adhesion between coating and substrate.


I hope this has clarified the topic for you.
Best regards
Charles A.Bishop
C.A.Bishop Consulting Ltd

Tel +44 (0)1509 502076
www.cabuk1.co.uk

[Ranjit Jundre]

I am student of packaging institute presently working in multinational company.please tell me what is the method to find out optical density of metallized film which is laminated to other film and in with print or without print? thank u very much for the information u have display on web.

[Ranjit Jundre]

I am student of packaging institute presently working in multinational company.please tell me how can we prevent oxidation of aluminium in metallized films. Is there any lacquer or coating available to prevent oxidation.Thank u very much in advance for ur help.

[Sam]

In general, which of the following processes in low pressure plasma treatment are accomplished by inert gases, reactive gases, or electrons.

Ablation (Etching)
Deposition
Cross-linking
Functionalisation (Surface Activation)

Thanks

[vikas Aggarwal]

Is there a system of checking for number of pinholes\weak spots in a metallised film online ie.during metallising\slitting?

[Sutjipto]

Hi, I just want to know the type and specification of aluminium used in Flexible Packaging? Is there any book I can read in orde to find it out?

Thank you and Best Regards
Sutjipto

[ranjit jundre]

Dear Dr. Bishop
Thank you for your answer about my previous enquiry. I am facing some of the following problems and have some queries please give me your advice and solutions.
1) I have analyze some of products available in the market which are packed in the metallized packs mostly having structure PET/MET-PET/LDPE. When these products are stored undre hot and humid conditions demetallization of the pack starts( which can be easily noticed when observed with torch or any light source) e.g. spices, pickles, chili powder, coriender powdre,etc.
what is the reason for such demetallization? how can we prevent that? if prevention is not possible how can we extent the period of demetallization? Is there any need to improve method of metallization or any equipment avilable which can produce such meatallize film which can solve the problem of demetallization?
2) What is the optical density required for corrosive or aggressive products to pack in the metallized PET laminate ?
3) Is it possible to carry out metallization with aluminum alloy? if yes what type of equipment used for this
4) Please tell me the comparison between process of metallization and comparison between properties of the MET-Paper, MET- LDPE, MET-PET, and MET-BOPP.

Thank you very much in advance
Regards,
Ranjit Jundre.

[ranjit jundre]

Dear Dr. Bishop
Thank you for your answer about my previous enquiry. I am facing some of the following problems and have some queries please give me your advice and solutions.
1) I have analyze some of products available in the market which are packed in the metallized packs mostly having structure PET/MET-PET/LDPE. When these products are stored undre hot and humid conditions demetallization of the pack starts( which can be easily noticed when observed with torch or any light source) e.g. spices, pickles, chili powder, coriender powdre,etc.
what is the reason for such demetallization? how can we prevent that? if prevention is not possible how can we extent the period of demetallization? Is there any need to improve method of metallization or any equipment avilable which can produce such meatallize film which can solve the problem of demetallization?
2) What is the optical density required for corrosive or aggressive products to pack in the metallized PET laminate ?
3) Is it possible to carry out metallization with aluminum alloy? if yes what type of equipment used for this
4) Please tell me the comparison between process of metallization and comparison between properties of the MET-Paper, MET- LDPE, MET-PET, and MET-BOPP.

Thank you very much in advance
Regards,
Ranjit Jundre.

[Victor Legarreta]

I would like to know what is the process of "patterning metallizing".