[lotech]

I got an annoying problem that, some of my tablet and phone cases, umbrella handle and mouse...etc. with a rubbery finish that melted in time and became sticky, I even saw liquid seeped out from the tablet case at room temperature. The first time I encountered such a problem was with an early Thinkpad notebook with a soft rubbery finish, what was that material that I can avoid in future purchasing ? I have some other cases that have no such problem, and I know that the melting problem can be fixed with baking powder but that's temporary, the problem will come back again, so I want to completely avoid using such material.

[MarkJerling]

It sounds like some of these materials are not stable. There could be a chemical reaction reason for this, perhaps with VOCs, or it could be that some of these goods simply are cheaply made and the plasticizers are not stable to start with.

[lotech]

Fyi, that's the type does not melt.

amazon.com: Fintie Shockproof Case for Samsung Galaxy Tab A 10.5 2018 Model SM-T590/T595/T597, ?tag=pentaxforums-20&[Tuatara Magic Ring] [360 Rotating] Multi-Functional Grip Stand Carry Cover w/Built-in Screen Protector, Black : Electronics


And this type melted.

amazon.com: Samsung Galaxy Tab A7 Lite Case 8.7&?tag=pentaxforums-20'' with Screen Protector | Pencil Holder [360 Rotating Hand Strap] &Stand, SEYMAC stock Drop-Proof Case for Galaxy Tab A7 Lite 2021 SM-T220/T225/T227 (Black) : Electronics

[hcarvalhoalves]

These rubbery finishes always break down eventually, depending on heat and UV exposure.

The only way I know to avoid it is to protect before it gets sticky. There is a silicone-based product aimed at car enthusiasts to restore rubber that works for that.

Once it gets sticky, all that's left is strip it off with isopropyl alcohol.

[lotech]

These rubbery finishes always break down eventually, depending on heat and UV exposure.

The only way I know to avoid it is to protect before it gets sticky. There is a silicone-based product aimed at car enthusiasts to restore rubber that works for that.

Once it gets sticky, all that's left is strip it off with isopropyl alcohol.

Thanks for the info., there are some other rubber like material does not melt at all even after long time use, such as those cheap transparent cell phone cases I never have problem with, and I hope Pentax will pick the right one for their new camera !

[cmohr]

One of the big things that attacks some plastics/rubbers in this way is Ozone. Many Kitchen and household appliances produce Ozone, and increased level in the home or office can affect soft plastics. Live in an area with bad smog from cars exhaust, that ozone.

Best to go for Silicon cases holders ect if looking for resistance against breaking down, and avoid strong solvents/cleaners.

[lotech]

One of the big things that attacks some plastics/rubbers in this way is Ozone. Many Kitchen and household appliances produce Ozone, and increased level in the home or office can affect soft plastics. Live in an area with bad smog from cars exhaust, that ozone.

Best to go for Silicon cases holders ect if looking for resistance against breaking down, and avoid strong solvents/cleaners.

Yes I know about Ozone and I got a couple of such air purifiers but that's not the cause for rubber/plastic breakdown, I believe exposure to UV light was the cause. And those Ozone air purifiers has a plastic chassis but never break down, so that the type of plastic material in use matters. Btw another major source of Ozone is copier and laser printer that produces Ozone as byproduct via high voltage, also some Negative Ions as well.

[kypfer]

I've got a "rubber" coated wind-up torch hung on the back of the door for "emergencies" … it's not in sunlight or other UV source, there's no ozone generating equipment anywhere close and there's a fairly regular passage of fresh air, but it gets as sticky as a sticky thing!
It's simply the breakdown of poor-quality material … I've known the covering on Minolta a/f lenses and several other instances suffer from similar issues.
Corners being cut to save manufacturing costs

[BigMackCam]

I've had numerous items of non-photography equipment that succumed to this... also, two pieces of photographic gear - a rather decent Konica Minolta 17-35mm f/2.8-4 D AF lens (the zoom and focus rubbers were very tacky) and a Minolta 35mm compact (the grip) - can't remember which model, but one of the plethora of simple point and shoots from the 1980s / 90s. I was able to rescue the Konica Minolta lens using cotton buds dipped in 90% isopropyl alcohol and some alcohol-based lens wipes. Obviously it took a layer of rubber away, but only very little from what I can tell - and both the zoom and focus rubbers are quite thick, so there was plenty of material to work with. The interesting thing is, that was probably seven or eight years ago, and it hasn't needed any further treatment since. I haven't used the lens in over a year, but checked it just now and it feels perfect

[35mmfilmfan]

I have a couple of (very !) second-hand zoom lenses that suffered from this. Eschewing the baking powder or alcohol approaches, I merely cut strips of gaffer tape to fit the affected areas, and covered them in that. This has the added advantage of making it extremely unlikely that any felonious ne'er-do-well will half inch them !