Serious concerns about off-gassing in cases

[mar3o]

I've been concerned about this for years, but I rarely see it mentioned. Some brands of cases, like Viva Elite, seem to off-gas, from what I've been able to learn about it. Over time an oily residue or coating builds up on the inside of the case, and even accumulates on the disc surface itself. Sometimes I see it on brand-new releases. Some cases/brands don't seem to have an issue with it.

As I'm buying more UHDs I'm seeing this more and more. I don't know if that's because it's an even bigger problem with UHD cases, or maybe just because they are black so it's much easier to see the residue as opposed to blu-ray cases. I've seen lots of my blu-ray cases develop this issue over time too, and I fear this will cause the discs to deteriorate over time. It takes a good 10-15 minutes at least to fully clean off a case inside, using a microfiber cloth to absorb it all, trying to cover all the nooks and crannies in there, all of which are coated to various degrees. But it's not feasible to clean them all. And I've cleaned some UHD cases just to see a few months later it's already starting to build back up. There's no way I can go through all my cases every few months and clean them all again. That's unrealistic.

Here's a couple pictures I took of the inside of Peter Jackson's King Kong UHD this evening. This one has it real bad, and though not all my cases look this bad, many do have a noticeable coating inside. I can run my finger across them and it leaves a streak. I bought this one sometime in 2019 I think.





Why don't we hear more about this? I've seen a couple comments in the UHD threads saying when they have playback issues they clean their discs off and they can see a film on them sometimes. Why are people accepting this? I don't ever remember having issues like this with DVD cases. I still have lots of empty blank DVD cases from long ago and they still look fine inside even today. Are people just not noticing this? Why is it acceptable that these cases are made of a material that build up this oily residue that ends up on the discs? As you can see it's also nasty to look at and I have no idea how toxic that oily substance is to touch. My apartment has plastic items all over everywhere and they don't have this off-gassing issue. What is it about these cases that makes this happen?

It's stuff like this that keeps me up at night. I've been planning to go through all my UHD cases to clean them, but it's an overwhelming amount of work, and it will likely just come back anyways.

I'm very concerned about this. There's no way this oily substance is good for the discs long-term.

[Vilya]

I have found this residue on discs of all formats and it cleans right off and the disc plays fine. Transferring the cleaned disc to a new case is an option or just clean the disc again as needed. I have never lost any discs to this residue in all the many years that I have been collecting them.

[JohnAV]

I thought it was funny this seems to the equivalent of big foot in these forums.

From another forums 12/2/2013

That sounds troubling. I've read some paranoia over on Blu-ray.com about residue inside BD cases but I've never found anything like that in any of my DVDs/BDs.
This is how I store my collection and I've never ran into any problems:

That looks like moisture (humidity?) or like something is too cold. I have hundreds of disks, never seen it. All mine are stored on a ground floor room vertically or horizontally with the cardboard sleeves. Possibly you have many of these plastic cases all jammed next to each other which didn't allow for air circulation.

[HorrorBlu]

I always assumed this was something from the pressing plant. I've seen it in newly opened discs, but have never had it on a disc that has been just sitting in my collection over time.

[Vilya]

Originally Posted by JohnAV

I thought it was funny this seems to the equivalent of big foot in these forums.

From another forums 12/2/2013


That looks like moisture (humidity?) or like something is too cold. I have hundreds of disks, never seen it. All mine are store on a ground floor room vertically with the cardboard sleeves. Possibly you have many of these plastic cases all jammed next to each other with didn't allow for aeration also.

It is an oily film that is sometimes a consequence of injection molding of the plastic cases commonly known as outgassing. It doesn't happen all the time, but when it does it can easily be cleaned off of the disc. It is a nuisance only in my experience.

Here is a more detailed post that I wrote about the subject awhile back:

Originally Posted by Vilya

I mentioned Viva Elite because they were recommended to me and I have not experienced the issues that you apparently have. Other brands of cases are certainly available.

Blu-ray disc cases are made with a plastic called Polypropylene (PP), specifically polypropylene homopolymer. DVD cases are made with Polystyrene (PS) also known as Plastic #6.

https://omnexus.specialchem.com/sele...ene-pp-plastic

Most plastics "outgas" and at different rates under different conditions.

"Most plastics contain volatile organic compounds (VOCs). These are poisonous, carbon-containing chemicals that are volatile enough to evaporate even at room temperature."

"For example, a shower curtain made with PVC can outgas for a month or longer and high temperature and humidity tend to speed up the process."

New shower curtains often reek!

https://www.directplastics.co.uk/abo...hould-you-care

Improper venting during the injection molding of plastics can exacerbate outgassing.

"Proper venting is essential to molding a defect-free part. Without it, air and gas are trapped in the mold, which compress and heat as the cavity fills. Trapped gas is one of the most common causes of part burns, and it can also lead to short shots and voids, blemishes and discernible knit lines that weaken the part.

Moreover, trapped gas can cause residue buildup in vented pins, which then necessitates frequent production interruptions to clean the tool. It can even cause corrosion of the tool steel, thereby increasing tool-maintenance costs."

https://www.ptonline.com/articles/ho...ection-molding

"When a Blu-ray case has been wiped clean inside, snapped shut, and tucked away inside a cabinet, none of those contaminants are present. Yet after several months or so, the residue will reappear inside the case. That's evidence of outgassing."

https://forum.blu-ray.com/showpost.p...2&postcount=22

Slip and other agents added to the process can certainly cause problems, too, if not done correctly. All of these are quality control concerns.

I once worked in a factory that did injection molding and those machines were quite persnickety. Defective parts were common if these machines were not meticulously maintained. I worked in a neighboring department where adhesives were mixed; I made different kinds of glue all day. Nasty job that I was happy to leave after just two years.

Originally Posted by Vilya

The Polypropylene cases are the bigger offenders for outgassing by far. I do not think I have had any cases of noticeable outgassing residue with my Polystyrene dvd cases.

Kinda ironic that the better format gets the lesser quality case.

The clear slim line cases are Polypropylene whereas the solid black ones are Polystyrene and the former can often be found in multiple disc sets of either format.

4K disc cases, like blu-ray cases, are Polypropylene and Polypropylene is much more "flatulent" and prone to outgassing than is Polystyrene.

[mar3o]

Originally Posted by JohnAV

I thought it was funny this seems to the equivalent of big foot in these forums.

From another forums 12/2/2013


That looks like moisture (humidity?) or like something is too cold. I have hundreds of disks, never seen it. All mine are stored on a ground floor room vertically or horizontally with the cardboard sleeves. Possibly you have many of these plastic cases all jammed next to each other which didn't allow for air circulation.

It's oily. You can run your finger across it and it leaves a "clean" streak. As I said, some cases come like this and they're literally new releases. I don't think it's humidity. My apartment varies in humidity from around 28-40% in the winter to 60+% in the summer. But like I said this seems like a residue issue from the plastic material. Other threads in the past have referred to it as off-gassing.

Of course my cases are all packed up against each other vertically. How else would I store them? I have them stored in rows across my media shelves.

[Vilya]

Originally Posted by mar3o

It's oily. You can run your finger across it and it leaves a "clean" streak. As I said, some cases come like this and they're literally new releases. I don't think it's humidity. My apartment varies in humidity from around 28-40% in the winter to 60+% in the summer. But like I said this seems like a residue issue from the plastic material. Other threads in the past have referred to it as off-gassing.

Of course my cases are all packed up against each other vertically. How else would I store them? I have them stored in rows across my media shelves.

The term is "outgassing" to be precise. You can Google the term and delve as deep into the fascinating world of the injection molding of plastics as you wish.

The residue is easily removed by a simple cleaning, but if the disc is returned to the same case the residue will likely return. I have never lost a disc to outgassing, not a single one in the 24 years since I bought my first DVD in 1997.

[mar3o]

What concerns me is what will it do to the discs over time? I have discs I don't touch for years. I fear this coating over time may degrade the disc. I know Vilya above has said he never had any issues. I guess that's comforting, but it's hard for me to believe this oily, misty layer that builds up on the discs in some cases from this off-gassing wouldn't be at least somewhat harmful to the disc surface.

I've been tempted lately to clean off the insides of my cases when I buy new releases but since hundreds of my discs may be affected I can't possibly clean them all, especially if it just starts accumulating again.

What I don't get is why they use this type of plastic. Even if it's harmless to the discs (carcinogenic maybe?), it still looks awful if it gets bad like my King Kong set. Imagine if everything we bought that was plastic did that - speakers, plastic utensils, remotes - why not use a plastic that doesn't do this? I'm still not convinced this is harmless to discs. Maybe over the short term the discs will still play, but what about 10 more years down the road? I want this media to still work 10-15 years from now, like my DVDs still work.

[mar3o]

Originally Posted by Vilya

The term is "outgassing" to be precise. You can Google the term and delve as deep into the fascinating world of the injection molding of plastics as you wish.

The residue is easily removed by a simple cleaning, but if the disc is returned to the same case the residue will likely return. I have never lost a disc to outgassing, not a single one in the 24 years since I bought my first DVD in 1997.

Ah yes, outgassing. You're right - for some reason I've been calling it off-gassing.

I feel better knowing you've never run into any disc failures due to this. I still can't figure out why they use plastic that does this. I'm pretty sure some cases are a different plastic material and don't have this issue. In fact my Buck Rogers box set came with two seasons in two different brand plastic cases - one is the Elites that have this issue, and one was a harder, sturdier cases that doesn't seem to have the issue.

Perhaps rather than worrying about cleaning each case inside, which is an impossible task, maybe every week I'll take a bunch of discs out that I haven't touched in years and give them a quick wipe with a microfiber cloth just to remove any residue from the surface. That should at least help for discs I haven't touched or cleaned in years.

[Vilya]

Originally Posted by mar3o

What concerns me is what will it do to the discs over time? I have discs I don't touch for years. I fear this coating over time may degrade the disc. I know Vilya above has said he never had any issues. I guess that's comforting, but it's hard for me to believe this oily, misty layer that builds up on the discs in some cases from this off-gassing wouldn't be at least somewhat harmful to the disc surface.

I've been tempted lately to clean off the insides of my cases when I buy new releases but since hundreds of my discs may be affected I can't possibly clean them all, especially if it just starts accumulating again.

What I don't get is why they use this type of plastic. Even if it's harmless to the discs (carcinogenic maybe?), it still looks awful if it gets bad like my King Kong set. Imagine if everything we bought that was plastic did that - speakers, plastic utensils, remotes - why not use a plastic that doesn't do this? I'm still not convinced this is harmless to discs. Maybe over the short term the discs will still play, but what about 10 more years down the road? I want this media to still work 10-15 years from now, like my DVDs still work.

Most plastics outgas; how much so varies with the type of plastic, how well it was manufactured, and the environmental conditions in which it is stored and used. Again, it is why a brand new plastic shower curtain stinks to high heaven when you first open the package; the plastic curtain remains odorous until the outgassing subsides.

Properly manufactured Polypropylene won't have an outgassing problem; that's why only some cases are a problem while most are not. Polypropylene is a more flexible plastic than Polystyrene. Excessive outgassing is a manufacturing defect that is not exactly rare with the injection molding of plastics. Again, blu-ray cases and 4K disc cases are Polypropylene and this plastic is far more likely to have outgassing problems than is Polystyrene which is what those rigid black DVD cases are made with.

Cleaning a plastic case that outgasses badly enough to leave noticeable residue won't do any good as the outgassing will likely still continue. Replacing the case or cleaning the disc again as needed are your choices.

The outgassing from these cases forms a residue on the disc, but it does not penetrate the hard disc coating on the disc itself nor does it penetrate the plastic laminate that seals the disc's data layer(s). If it did it would not simply wipe off. It is kind of like steam that forms on your bathroom mirror after a nice hot shower; it easily wipes off leaving your mirror unharmed.

Again, I have never lost a disc to outgassing plastic cases in the 24 years since I bought my first DVD. The residue is a nuisance, but it will not destroy your discs.

[mar3o]

Thanks for explaining this in more detail. Would it make any sense to periodically go through my discs a bit at a time and give them a quick cleaning? If the cases are just going to continue to outgass it will just build back up on the discs anyways I guess, but at least it would keep it from building up too bad. I've definitely noticed lately a lot of my UHD cases have this issue. King Kong was the worst one I've seen but many have that greasy film. No point in trying to replace them all, and I don't have money to just buy boxes of new empty cases just to discover they'll have the same issue.

So why did they switch from the Polystyrene DVD case material to the Polypropylene blu-ray/UHD cases use? Cheaper I imagine. Too bad this wasn't considered when they made that decision.

[Vilya]

Originally Posted by mar3o

Thanks for explaining this in more detail. Would it make any sense to periodically go through my discs a bit at a time and give them a quick cleaning? If the cases are just going to continue to outgass it will just build back up on the discs anyways I guess, but at least it would keep it from building up too bad. I've definitely noticed lately a lot of my UHD cases have this issue. King Kong was the worst one I've seen but many have that greasy film. No point in trying to replace them all, and I don't have money to just buy boxes of new empty cases just to discover they'll have the same issue.

I just don't worry about it. I look at my discs before I put them in my player and if I notice this residue I clean the disc. You do not need to establish a disc cleaning regimen or schedule; clean as needed.

Eventually the outgassing should subside, but the wait may be a long one.

Polypropylene's flexibility is arguably a better material in that its ability to bend more makes it less likely to break than Polystyrene. Polystyrene is strong, but its rigidity makes it easier to break under some circumstances. It is like the old story about the tree snapping in the wind while the reed bends.

I don't know which one is cheaper to manufacture, but Polystyrene is still used for most DVD cases while Polypropylene is used for blu-ray and 4K disc cases. I'm sure that they have their reasons for using these plastics as they do.

[Geoff D]

Originally Posted by JohnAV

I thought it was funny this seems to the equivalent of big foot in these forums.

From another forums 12/2/2013


That looks like moisture (humidity?) or like something is too cold. I have hundreds of disks, never seen it. All mine are stored on a ground floor room vertically or horizontally with the cardboard sleeves. Possibly you have many of these plastic cases all jammed next to each other which didn't allow for air circulation.

I've had this residue on countless UHD/BD cases bought new, it's got nothing to do with how they're stored at home. First thing I do when I open them up is give the hubs a jolly good clean.

[Lee A Stewart]

Polystyrene is cheaper than Polypropylene. It lacks PP's higher heat resistance, flexibility and non-reaction to certain chemicals.

[Scottishguy]

*farts*

[canucksam]

Interesting thread. It explains why I see that residue most often on slow selling discs that have been closed up in plastic for years.

Who says this site isn't educational?

[Scottishguy]

Looks more like moisture build up, plus a little residue, to me. Where are you exactly storing them? Are they all vertical? You aren't keeping them in plastic bag things are you?

https://www.youtube.com/watch?v=FXHk...ature=youtu.be

[RCRochester]

Originally Posted by HorrorBlu

I always assumed this was something from the pressing plant. I've seen it in newly opened discs, but have never had it on a disc that has been just sitting in my collection over time.

Same here. I've had a couple new purchases that have that residue on the case, I just toss it and replace it with a new one. I've yet to see this on anything that's been sitting on my shelf. I wonder if the environment where the person lives might play a part, like climates that are warmer and more humid might experience this more?

[Scottishguy]

Originally Posted by RCRochester

Same here. I've had a couple new purchases that have that residue on the case, I just toss it and replace it with a new one. I've yet to see this on anything that's been sitting on my shelf. I wonder if the environment where the person lives might play a part, like climates that are warmer and more humid might experience this more?

Florida.

[smithb]

I've posted about this a couple of times over the years, as it comes back up every so often.

I did some investigating over my collection about 10 years back when I had a few disks go bad after they developed a visibly dull cloudy appearance. For some I was able to wipe away the cloudy appearance, others I could not. I noticed with those disks that could be cleaned that if I provided a slight mist to the surface I could see patches of film where the mist did not dissipate as quickly. Without the mist the film was unseen. I started checking new disks as I received them and a percentage of them all had the same issue. What was really odd was the shape of the film. Most were just oddly shaped patches. However, I recall one with four small symmetrically circles even spaced. Another, in an eco-case where the patches were aligned to the spokes. I surmised it couldn't just be from out-gassing, but more likely how disks move though the manufacturing process, as they do they can pick up some additional filmy substance. Possibly, the out-gassing of some cases as an adverse effect on the film. Possibly, the film can potentially permeate below the disk protection. I've never had issues with blu-rays, only DVD's.

What I do know is that the film is easy to spot with light steam (can be created from the moisture of ones breath), it is easily removed, and I've never had it come back once removed. I've not had any disks go bad since.

I don't expect people to take what I've said seriously, nor do I care, I'm just relating my experiences to those that may want to try it themselves.