Barrier Effect
Barrier Effect
(OP)
Can anyone recommend an additive or process that would make a polyolefin (injection molded) less permeable to oxygen or water vapor?
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RE: Barrier Effect
Fluorine treatment certainly improves barrier properties of PE to hydrocarbons, and is in fact used on fuel tanks and plastic Jerry Cans.
I can enquire as to it's effects on water and O2 in late Jan if you need further help then.
Where are you located, and why do you want to do this, as other solutions to your problem might be possible.
Regards
pat
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RE: Barrier Effect
I do not need specifics about oxygen or water vapor, these are just examples I picked arbitrary. I am located in Florida. I am looking to an alternative to fluorination. What other process may achieve similar results (creates a barrier in a polyolefin such as PE or PP)? Is there an additive that would produce a barrier effect?
Hector
RE: Barrier Effect
Regards
pat
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RE: Barrier Effect
I am working with existing products that are made of PP and PE. It is hard to replace these materials and keep the cost in the same range.
Hector
RE: Barrier Effect
If you can eliminate the fluorination process, it might more than compensate for a material change.
Regards
pat
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RE: Barrier Effect
RE: Barrier Effect
To answer telaviv questions, regarding the level of protection, at this point I am interested in what I can get. The process is injection molding.
RE: Barrier Effect
Barrier and cost ballance is the main reason it is used for beverage bottles. You mightneed a post moulding crystalisation process to get optimum barrier.
It will never be quite as impermiable as stretch blow moulded PET as the stretching process lines up the molecules and crystals to an extent that cannot be achieved by heat treatments alone.
Beverage bottles are obviously approved for food contact.
Despite this being an exceptionally large market (I guess quite a few billion $ US per year world wide), no one has come up with a better alternative to date. You can bet many have tried.
Regards
pat
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RE: Barrier Effect
There are many ways that you might be able to lower the fluorination treatment costs. The cost will depend on container size and shape, number (peak load and baseline), and application (barrier to what, or protection from what, and for how long). It will also depend on whether you do the treatments on-site yourself or have to pay for treatments performed by a third party.
As you may guess from my handle, this is an area that I work in a lot.
RE: Barrier Effect
This is used to lower the permeation in blow moulded bottles and drums.
The principle is mechanical in that the Nylon forms platelets and like overlapping armour this produces a tortuous path for the escaping molecules.
I don't know if it will work with injection moulding because the mechanical shearing effect is different.
Regards,
Robin Enderby
RE: Barrier Effect
Am interested in whether flourination would be helpful in my situation outlined below.
From: Philip Anthony, President
VertiGONE, Inc
Regarding: Plastic Permeability Problem
Dear Sir:
My company is involved in a multiyear bet-the-company development activity. We are developing a consumer medical product. This product is a goggle device, which gives the user a visual pathway to follow for a recognized therapeutic head movement. The device involves a plastic gyroscope-like device. This device has a buoyancy neutral inner sphere floating in a fluid in a clear plastic outer sphere. We have encountered significant problem when we used water for the fluid to be contained in the outer sphere. We have found that the water permeated through the outer sphere material. The outer sphere has been produced in CYRO Technologies Acrylite Plus ZKM and GE Plastic Lexan 143.
We found the attached information, which explained the water permeability of both of these materials. By using silicone oil 20 cst with the higher molecular weight we anticipated that we should get containment of the outer sphere fluid as well as a specific gravity close to that of water such that previously produced inner spheres of SG =1 could be used. We have found that mineral oil is well contained within outer spheres made of both of the above materials, but the specific gravity is not close enough to allow use of previously produced inner spheres.
The questions: 1) Will silicone oil with a higher viscosity be contained within the outer spheres of either of the above materials? 2) Do you have other materials that you would suggest for this activity? Bear in mind that the material used needs to be nontoxic to the user. If this question is not in your area of expertise could you refer me to a knowledgeable source?
Thank you,
Philip Anthony
RE: Barrier Effect
Investigate the possibility of a material called Topas, made by Ticona. It is USP approved, optically excellent, sterilizable, etc etc.
At present a bit pricey but it is supposed to have outstanding barrier properties (for water).
Rgds
Harry
RE: Barrier Effect
Thank you for your reply; do you know what percent of Sevlar (by weight) is added to PE, to give it barrier properties? For example 1%, 5%, 20%, etc.
Hector Barea
RE: Barrier Effect
I guess that the barrier gets better with the amount used. I think 10% is the starting point, but I suggest you contact your local DuPont dealer.
Good Luck,
Robin Enderby
BMC Ltd. UK
ps sorry for the delay in responding - I don't visit this forum often.