PVC and Rubber

Possibly exposed to bleach, hydrogen peroxide, or some other chemical...

Thank you! I was actually looking into the effects of Dicumyl Peroxide. Is it possible that the problem is actually in the surrounding (fumes, diffused chemicals, volatiles) plus an air-conditioned room, and not in the material itself?

More than likely that is the case....

thank you!

If you then take the sandal outside, does the color return? I wouldn't expect that to happen, but it would perhaps prove that heat and humidity isn't playing a role....

it does not actually. it remains faded. we have red, blue, green, yellow and black.

all with the same formulations for pvc. the only colors that were uncooperative were red, blue, green. there were no changes in yellow and black. all same exposures and environment.

That's strange. I would have thought it would be more affected by the ultraviolet light in sunshine. Maybe there is a difference between the two samples. Try bringing the outside one in and see if it fades inside.

we actually tried it in our area. stocked it inside the office which is an air-conditioned room as well. there were no changes

we are looking into volatility of peroxide and the possible concentration of some chemicals in their plant.

Are you saying that the ones stocked outside did not fade when brought inside, but the ones that were never outside, did fade?

If that is the case, it seems being outside prevents fading. Two possibilities come to mind: Fresh air carried away some substance that is outgassing from the rubber or PVC, or, more unlikely, the ultraviolet in the sunlight had some effect.

Just a thought...

yes. though there may be a slight visible fading but definitely better than the sample stored inside an aircond office.

i think that's the term, "outgassing". thanks!

It could be OZONE degradation.

thanks, i'll search on that as well.

Yeah, possible if UVC air purifier is in use.

https://molekule.science/which-air-purifiers-are-ozone-free-comparing-ionizers-uv-c-and-hepa/

so it's possible that the ozone build-up caused by this air purifier affects the rubber and pvc ? did i get it right? thanks!

All PVC is not the same any more than all cookies or even people are the same. Formulation is critical. If it's flexible, maybe around 60-65% is actual PVC resin. Was there a UV absorber in the formulation? What colorants were used? The rubber was probably black (sole) so it's protected that way. Too many other details to go into here.

yes, flexible/plasticized pvc for the sandal strap. definitely contains UV absorbers and antioxidants etc. They said the slipper rubber's odor is too strong when packaging is first opened.

"Contains" is not enough. Quantity matters (Paracelsus around 1530 AD), which we still ignore when convenient. How much absorber, or maybe they left it out that day. How much air contaminant for how long, ventilation? If it affects sandal color what else in the room is or is not affected?

PVC doesn't use antioxidants. TPO does, so maybe it isn't PVC at all. Does it float/sink? As for odor, that could be plasticizer or heat stabilizer in PVC as well as the rubber, and may not relate to color fading. Some of the best heat stabilizers also smell the worst. UV absorbers usually don't smell. Two weeks is very short for fading. There is a lot i don't know so please forgive guesses. But there are reasons for things, no miracles in chemistry (which is why people are afraid of it).

Thanks! that's what i'd really like to know. the concentration of air contaminant/ fumes/ volatiles. ( hope i'd get to go there soon.) thank you

First thing that pops into my head is drywall contamination/outgassing. If you are thinking two internal environments are ostensibly the same, this has been a well-known issue.

Do a Google search on contaminated drywall.

Good luck.

thank you, ive never heard of that before. will look into that one.

Many years ago I sold specialty chemicals to hundreds of different customers in dozens of different industries. You need to gather and organize a good deal of information involving the problem so that you can present it to chemists. Some thoughts/questions:

1. It is unclear whether you (your company – in its own facility) manufactured the items. I am tending towards that not being the case. The latter will make your quest more difficult by a significant factor as you will be evaluating the veracity of their statements.
2. It appears that your customer found an objectionable odor when the individual (sealed?) packages were opened. The room that they “aired out” in was air-conditioned. They felt that this was needed before the products could be marketed.
3. Are the items that you are airing out in an air-conditioned room from the exact same manufacturing batches?
4. How long from the manufacturing date was each individual PVC component exposed to the off-gassing from the rubber component in a small sealed (?) package?
5. If the components were manufactured in your facility what protocols are in place to clean any common processing equipment between runs of similar or disparate products?
6. What other items were being manufactured in parallel in the plant such that fumes from that process could be captured in the sealed packages?
7. Were all the rubber products from the same supplier and/or made at the same time?
8. The rooms that the items are being aired out in might have drywall panels. The date of construction of the different rooms could be relevant due to possible contamination of the drywall. (One of my customers manufactured drywall but this was several decades ago.)

I am sure that your chemist or consulting chemist will have more questions.

Good luck.

actually, we supplied the PVC material and we received a complaint that the color either, darkens and fades. they are very specific with the color blue because it blackened within just 2 weeks.

regarding the odor, i think the sandals coming out of the machine are immediately packed, that's why the odor after opening it is strong.

yes, the sandals came from a specific batch.

they said they stored it in for more or less 2 weeks.

regarding question 5 &6, im really not sure.

the rubber material came from one manufacturer only

i'd like to hear them consider that part so i wont have to be confused anymore:D or the UVC air purifier/ ozone contributing purifiers:D

thank you!

If you do not already subscribe, Google Scholar suggests that this journal might be helpful to subscribe to, so as to browse through its issues and articles: https://www.sciencedirect.com/journal/polymer-degradation-and-stability

To wit: https://www.sciencedirect.com/science/article/pii/S0141391010002818

I used to blend and vacuum-fire porcelain to create artificial teeth. It required an understanding of how the mixing of stains/colorants would affect hue, value and chroma. It sounds like you will become an expert in this shortly.

Needless to say, you need to obtain samples of -- if not all of -- the aberrant batch(es).

I feel fairly certain that you do not want to author an article on dermal sensitivity and longitudinal treatments of same.

Does the space use an electronic air filter and if so, what is the ozone level in the space?

just a thought.. clean and fresh air?

I tend to think this is an issue with the color formulation interacting possibly with the polymer formulation...the difference in the samples placed outdoors seems like the heat caused VOC levels to decline rapidly or accelerated outgassing...the samples indoors retarded this process and as a result caused the colors to fade...It's possible that the colorants used are not compatible with the pvc formulation being used or that an additional step is needed to stabilize the combined formulation...possibly a hot water bath with some combination of baking soda and or vinegar....and or possibly a hot air dryer heated to a certain temperature, for a certain amount of time...in any case it seems there is a finishing process called for, or a reformulation of some sort....or maybe you just got a bad batch for some unknown reason....or chemical or uvc/ozone exposure during office sanitation process....