What causes plastic to yellow?

[justvinnie]

I wonder... PCP's reactive in the upper atmosphere to from diatomic haildes that can initiate a free radical chain reaction that destroys ozone. Is it possible that UV will do the same to PVC and other halogenated plastic polymers. If that's the case UV is worser than air oxidation.

vinnie

[CoryHolmes]

I wonder... PCP's reactive in the upper atmosphere to from diatomic haildes that can initiate a free radical chain reaction that destroys ozone. Is it possible that UV will do the same to PVC and other halogenated plastic polymers. If that's the case UV is worser than air oxidation.

vinnie

PVC? Not so much. What UVs real damage is that it causes the covalent chemical bonds that hold the molecular chains together to break, chopping the polymer into smaller, less stable chains; which in turn robs the material of much of its strength and other properties.

Like I said, PVC is pretty good at resisting the weather and sunlight, otherwise it wouldn't see much use in the outdoors.

And UV is much worse than oxidization, because the high energy of the UV rays work at a much faster pace than simple degridation. If you want to run a test for yourself, get two buckets. Leave one inside your house and one outside your house. Come back in 2-5 years. The one inside will be more or less good to go, whereupon the outside bucket will be yellow and will crumble in your fingers like eggshell as you try to pick it up.

[Neova]

Most toys nowadays are ABS, PVC or combo of both. Styrene is used less and less due to much more complicated molds and the need for strenght.

However, depending on the requirements of the toys, UV blocking additives can be added to increase their ability to stay minty white (or keep original color) and to hold its strenght up, as Cory has said.

You can pretty much tell the quality of the plastic but cannot tell if UV inhibitors were added or not until your toy turns yellow.

Mr Color has a new clearcoat for modelers that has UV inhibitors (note UV can reduce the brilliance in your paintjobs) so I'll try it on a custom and see what happens.

[Kin]

though it's kinda strange... i bought a 1/35 2 years ago and it still hasn't got a single yellowing on the surface even though it has been used. That thing is more than 20 years old!

[nightmareB4macross]

Hi CoryHolmes,

Thanks for the clarification.

NB4M

[captain america]

Denture cleaner might help in some instances. There's also this....

http://www.brightsolutionsinc.com/?source=overture

Haven't tried it yet, but it seems like one of the only real dedicated plastic restoration compounds.

[Duke Togo]

What causes plastic to yellow?

Two words: Harmony Gold

Yes, they are that evil. Now all of the valk yellowing from the early 80's makes sense... Pay the royalties or pay the price.

[Duke Togo]

No smoking in my house,  so thats not an issue!  SMoking is gross and should be banned

I like to smoke cigars.. I blow the smoke in the faces of all the little girly men who are too sissy to stop their crying and pick up the weights.

Yeah, from what I hear, that's not all you smoke!

[Kin]

What causes plastic to yellow?

Two words: Harmony Gold

Yes, they are that evil. Now all of the valk yellowing from the early 80's makes sense... Pay the royalties or pay the price.

Amen!

I get that too from drinking too many beers til i have to "go"

[promethuem5]

I like to smoke cigars.. I blow the smoke in the faces of all the little girly men who are too sissy to stop their crying and pick up the weights.

Well thank you, oh great and useless one for contributing ABSOLUTLEY nothing to my thread. at least the otehr guys who posted stuff like PEE and FATE were joking around about the TOPIC of the thread. You on the other hand come in here with your nambly pambly 'I masturbate to pictures of Arnold'ness and waste our time by posting something we thoiught might have been useful untilwe read it. The only thing that satisfies me is the knowledge that you'll die of lung cancer before me....

[Duke Togo]

Actually, you don't inhale cigar smoke... more likely mouth, tongue, or throat cancer.

[kensei]

Try to keep your valks or whatever in a glass cabinet in a cool place too. Your stuff lasts a lot longer that way. If you can, do what I am going to do, add a 3M special film that is ever so slightly tinted that can block out at least 99.99% of UV rays (not that my valks are in the most sunniest room anyway, but you can never be too careful) and UV filters on lights. Even then, don't leave the lights on all day and night. They will still yellow, but I hope that see nothing at all until I kick the bucket.

[Agent ONE]

I like to smoke cigars.. I blow the smoke in the faces of all the little girly men who are too sissy to stop their crying and pick up the weights.

Well thank you, oh great and useless one for contributing ABSOLUTLEY nothing to my thread. at least the otehr guys who posted stuff like PEE and FATE were joking around about the TOPIC of the thread. You on the other hand come in here with your nambly pambly 'I masturbate to pictures of Arnold'ness and waste our time by posting something we thoiught might have been useful untilwe read it. The only thing that satisfies me is the knowledge that you'll die of lung cancer before me....

AAAAAHHHHHAHAHAHAHAHAAAAAAA!!!!!

First of all YOU were the one taking this thread off topic with your smoking comment.

As you were offended by my comments I can only assume you are one of those little girlie men who are affraid of the gym and probably even your own shadow... Don't worry about it! There is always time to change your life and get into the gym. I have know pleanty of guys like you who were weak... Before I chmanged their lives, their previous workouts consisted of falling down on the floor in a fetal position and crying themselves to sleep. Does that sound familar?

[Die, Alien Scum!]

This is why I come to MW; to read Agent ONE's posts so that I know who all the girly men are! ROFL!

Edited January 9, 2005 by Die, Alien Scum!

[Wes]

I like to smoke cigars.. I blow the smoke in the faces of all the little girly men who are too sissy to stop their crying and pick up the weights.

Well thank you, oh great and useless one for contributing ABSOLUTLEY nothing to my thread. at least the otehr guys who posted stuff like PEE and FATE were joking around about the TOPIC of the thread. You on the other hand come in here with your nambly pambly 'I masturbate to pictures of Arnold'ness and waste our time by posting something we thoiught might have been useful untilwe read it. The only thing that satisfies me is the knowledge that you'll die of lung cancer before me....

AAAAAHHHHHAHAHAHAHAHAAAAAAA!!!!!

First of all YOU were the one taking this thread off topic with your smoking comment.

As you were offended by my comments I can only assume you are one of those little girlie men who are affraid of the gym and probably even your own shadow... Don't worry about it! There is always time to change your life and get into the gym. I have know pleanty of guys like you who were weak... Before I chmanged their lives, their previous workouts consisted of falling down on the floor in a fetal position and crying themselves to sleep. Does that sound familar?

Whatever, we only know you do it because Arnold's in those cigar mags.

But is it only white plastic that yellows? Technically all plastic should do so sometime.

[kensei]

But is it only white plastic that yellows? Technically all plastic should do so sometime.

That would be true, but say on a coloured 1/48 VF-1J Max for example it would be harder to notice.

[Zentrandude]

hmm so would yellow plastic yellow?

[sabretooth]

agent one = ass milker

cigars are for dorks who have tiny winkies

[Mechamaniac]

I wish I had taken pictures of the PG RX-78 Gundam I got in an Ebay auction last year.

The thing was BROWN when I got it, and when I opened the box, the smell of permeated smoke nearly knocked me out.

Luckily, smoke only causes external damage for the most part, I took all the armor off, and dunked them in a bucket full of Oxy clean & Water, and now it looks brand new.

[promethuem5]

Other colored plastic DOES yellow.... My Gakken Cyclone is that light fairy green... but some of it is yellowed to a pea green.

[GobotFool]

Hey all, I've been working on creating a collection room that would be ideal for slowing the deteriortaion processes in plastics that results in yellowing, frailty, ect. Any tips?

[azrael]

Hey all, I've been working on creating a collection room that would be ideal for slowing the deteriortaion processes in plastics that results in yellowing, frailty, ect. Any tips?

425087[/snapback]

No direct sunlight. Slow down the oxidation as much as you can.

[GobotFool]

Hey all, I've been working on creating a collection room that would be ideal for slowing the deteriortaion processes in plastics that results in yellowing, frailty, ect. Any tips?

425087[/snapback]

No direct sunlight. Slow down the oxidation as much as you can.

425103[/snapback]

I've curious, I have some really nice white toys in my room, the shades are all down, so no direct blasts of sunlight are coming through, room is kept relativly cool and dry, still should I be paranoid about even the little very dim sunlight that makes it into the room?

[bandit29]

I thought smelly otaku who are so infatuated with their toys and who don't shower cause plastic to yellow

I know Oxy Clean will sometimes get rid of or reduce yellowing.

[kensei]

Hey all, I've been working on creating a collection room that would be ideal for slowing the deteriortaion processes in plastics that results in yellowing, frailty, ect. Any tips?

425087[/snapback]

No direct sunlight. Slow down the oxidation as much as you can.

425103[/snapback]

Also no smoking, put the toys at a side where there is little sunlight coming from the brightest time of the day, dark curtains, keep it at a temp less than 18 degrees celcius. have glass to contain your viewing angle of the toys, it will keep out all but the most penetrating UV rays. You can get a film for that anyway, by 3M, if you have the cash to spare.

[David Hingtgen]

"Existing" will yellow many plastics. And "the same batch of plastic" can yellow very differently, piece to piece. Anyone who's owned an SNES knows that despite being composed of many "identical" pieces of gray plastic, some parts of it will look factory-fresh even now, and some will be so yellowed they will be the same color as oak. Even pieces on the bottom, which never ever saw light of any kind. 10 years from now, don't be surprised if a 1/48 VF-1 has the left flap, nosecone, inner part of the left leg, airbrake and starboard main gear doors turn pure yellow, with the rest of the plane being pure white. All while still being inside the box MISB, inside a MISB case, inside a locked closet underground, painted black.

Edited August 15, 2006 by David Hingtgen

[CoryHolmes]

All while still being inside the box MISB, inside a MISB case, inside a locked closet underground, painted black.

425200[/snapback]

You forgot about the atmosphere-controlled environment. No wonder your toys yellowed

[Vermillion21]

After reading this thread ... has anyone's 1/48 DYRL Yamato valkyrie yellowed?

I'm a little concerned as I have my VF-1S on display in a room that does get a lot of sunlight each day, but not directly on the valkyrie. It is behind glass as well. Am I a fool? On crack? Should I immediately move the valkyrie somewhere else?

[Die, Alien Scum!]

After reading this thread ... has anyone's 1/48 DYRL Yamato valkyrie yellowed?

I'm a little concerned as I have my VF-1S on display in a room that does get a lot of sunlight each day, but not directly on the valkyrie.  It is behind glass as well.  Am I a fool?  On crack?  Should I immediately move the valkyrie somewhere else?

425518[/snapback]

My first two 1/48s, a Roy 1S and a Max 1A, are beginning to yellow ever so slightly after being displayed for around three years. It's barely noticeable, so I'm really not concerned about it. Besides, if they start to look bad I can always use them for customs.

[David Hingtgen]

PS--the SNES proves that non-white plastics can yellow, and can yellow even worse than white.

[Zentrandude]

Im starting to wonder if certain airborne bacteria or fungus if made contact with plastics can also turn plastic to yellow.

Anyone tried wiping a pure white plastic sheet with rubbing alcohol every once in a while and see if it will stay white?

So weird seeing this old post with a certain steak sauce in it.

Edited August 16, 2006 by Zentrandude

[Vermillion21]

My first two 1/48s, a Roy 1S and a Max 1A, are beginning to yellow ever so slightly after being displayed for around three years. It's barely noticeable, so I'm really not concerned about it. Besides, if they start to look bad I can always use them for customs.

Thanks for the feedback. But man, since the VF-1S cost me $150, I think I am going to have to move it somewhere else ... dark.

[CoryHolmes]

Im starting to wonder if certain airborne bacteria or fungus if made contact with plastics can also turn plastic to yellow.

Anyone tried wiping a pure white plastic sheet with rubbing alcohol every once in a while and see if it will stay white?

425700[/snapback]

First off, the vast majority of plastics are immune to biological effects; that's why they're used in your body. That being said, it's possible to modify some plastics so they're biodegradable (my company does that for our doggie bags, so both the bag and the dog waste within will decompose in compost piles).

As it's been said before, it's contact with oxygen and UV radition in sunlight that causes the yellowing of plastics. I keep meaning to take some pics of the rollstock in my factory, you can clearly see where air was exposed to some parts and not others.

So no, rubbing alcohol wouldn't do anything to prevent yellowing.

[Zentrandude]

I don't think yamato uses medical grade plastic in their valks.

But im going ahead on this experiment, if theres a fungus that eats cds there maybe a bateria that reacts with plastics like those oil eating bacteria found like a mile deep in the earth.

edit: oh this is interesting. While doing some perperation research I found an article saying "A group of researchers in Ireland recently discovered a strain of soil bacteria that can eat styrene" wonder if I should try a sheet of white plastic and stick it in the ground covered in dirt to see what happens after month.

Edited August 17, 2006 by Zentrandude

[Sumdumgai]

Someone should try applying renaissance wax to their valkyrie. Although it would be a pain in the ass to get every part of it, since you'd have to dismantle it.

Nice protective stuff though. I use it on my lightsaber replicas to keep them from rusting or having other aging/environmental things.