The most important ergonomic design criteria that my
testers report is "wipe clean" -- for all exposed surfaces
(appliances, controls, etc.).

OK, that puts limits on the types of textured surfaces that
can be used -- but that's not unsurmountable.

I heard lots of complaints of hand-held/operated devices that
"feel sticky" after a while. I had assumed this was just a
buildup of oils/dirt from hands, easily addressed if the surface
was designed for ease of cleaning (many devices have silly nooks
and crannies that are often unnecessary or cosmetic).

But, I've heard from several people that many devices *can't* be
cleaned. Or, more exactly, that cleaning doesn't remove the
"stickiness". (?)

I received a couple of such samples in the past week and
they *are* sticky. And, it doesn't appear to be something
that was "applied" (even accidentally) by user/use. it didn't
wipe clean with mild detergent and water. Or alcohol.

[I was reluctant to try more aggressive solvents for fear of
damaging items that I don't own!]

So, I spent the day digging through piles of kit at one of
the non-profits with which I'm affiliated. And, managed to
find an assortment of similarly "sticky" surfaces (some that
see human contact, others that are NOT intended to see contact!)

I've found these to have a coating (?) that is responsible
for the stickiness. And, that the coating appears to *develop*
this stickiness -- it's not present in all instances of an object
(age?).

With a LITTLE elbow grease and alcohol, I am able to remove the
coating and expose the "solid plastic" beneath. The stickiness
disappears with the coating's removal.

I recall having problems with "rubber" feet disintegrating
on various devices (e.g., all of my Sun enclosures now have
self-adhesive *felt* feet as a precaution against their
original feet turning to GOO and damaging the finish of the
bits of furniture on which they reside).

And, prompted by today's exercise, I noticed that the "rubber"
button to operate my electric toothbrush is becoming "sticky";
as if losing its chemical integrity.

I assume these other "sticky" items have a fine coat of a
similar substance applied to their HARD PLASTIC surfaces...
for "feel"?

So:
- what causes this?
- is there anything to prevent it's occurrence?
- why would manufacturers go this route if this was an expected outcome?
- are there other alternatives to alter feel/appearance without such
applications? (mild textures?)

On 07/06/2023 06:39, Don Y wrote:
> The most important ergonomic design criteria that my
> testers report is "wipe clean" -- for all exposed surfaces
> (appliances, controls, etc.).
>
> OK, that puts limits on the types of textured surfaces that
> can be used -- but that's not unsurmountable.
>
> I heard lots of complaints of hand-held/operated devices that
> "feel sticky" after a while.  I had assumed this was just a
> buildup of oils/dirt from hands, easily addressed if the surface
> was designed for ease of cleaning (many devices have silly nooks
> and crannies that are often unnecessary or cosmetic).
>
> But, I've heard from several people that many devices *can't* be
> cleaned.  Or, more exactly, that cleaning doesn't remove the
> "stickiness".  (?)
>
> I received a couple of such samples in the past week and
> they *are* sticky.  And, it doesn't appear to be something
> that was "applied" (even accidentally) by user/use.  it didn't
> wipe clean with mild detergent and water.  Or alcohol.
>
> [I was reluctant to try more aggressive solvents for fear of
> damaging items that I don't own!]

I have found that amazingly to me that brake fluid is remarkably good at
removing the depolymerised short chain polymer tack from such objects.
It may also alter the surface texture too if it takes too much off.

Test any such solvent on a small patch out of sight and see if it works
for you before risking it on the visible exposed parts.

Basically a combination of ozone and UV exposure degrades these soft
rubbery polymer and short chain stuff is horribly tacky. The hard
polymers tend to be more aggressively crosslinked and seldom fail this
way but in extreme environments they become brittle and craze instead.
>
> So, I spent the day digging through piles of kit at one of
> the non-profits with which I'm affiliated.  And, managed to
> find an assortment of similarly "sticky" surfaces (some that
> see human contact, others that are NOT intended to see contact!)
>
> I've found these to have a coating (?) that is responsible
> for the stickiness.  And, that the coating appears to *develop*
> this stickiness -- it's not present in all instances of an object
> (age?).
>
> With a LITTLE elbow grease and alcohol, I am able to remove the
> coating and expose the "solid plastic" beneath.  The stickiness
> disappears with the coating's removal.
>
> I recall having problems with "rubber" feet disintegrating
> on various devices (e.g., all of my Sun enclosures now have
> self-adhesive *felt* feet as a precaution against their
> original feet turning to GOO and damaging the finish of the
> bits of furniture on which they reside).
>
> And, prompted by today's exercise, I noticed that the "rubber"
> button to operate my electric toothbrush is becoming "sticky";
> as if losing its chemical integrity.
>
> I assume these other "sticky" items have a fine coat of a
> similar substance applied to their HARD PLASTIC surfaces...
> for "feel"?
>
> So:
> - what causes this?
> - is there anything to prevent it's occurrence?
> - why would manufacturers go this route if this was an expected outcome?
> - are there other alternatives to alter feel/appearance without such
>   applications?   (mild textures?)

It is an intrinsic mode of failure of soft PVC or rubber.

UV and ozone will do for them. The least bad option is to clean it off
with the right solvent which for the things I had was brake fluid.

TBH I only tried it because I happened to have some lying around and a
horribly tacky Psion 3C that was unusable as a result of its tacky
surfaces. Someone recommended it on the Internet - I didn't really
expect it to work but to my amazement it did and required much less
elbow grease than any of the other methods I had tried.

--
Martin Brown

On 07/06/2023 06:39, Don Y wrote:
> The most important ergonomic design criteria that my
> testers report is "wipe clean" -- for all exposed surfaces
> (appliances, controls, etc.).
>
> OK, that puts limits on the types of textured surfaces that
> can be used -- but that's not unsurmountable.
>
> I heard lots of complaints of hand-held/operated devices that
> "feel sticky" after a while. I had assumed this was just a
> buildup of oils/dirt from hands, easily addressed if the surface
> was designed for ease of cleaning (many devices have silly nooks
> and crannies that are often unnecessary or cosmetic).
>
> But, I've heard from several people that many devices *can't* be
> cleaned. Or, more exactly, that cleaning doesn't remove the
> "stickiness". (?)
>
> I received a couple of such samples in the past week and
> they *are* sticky. And, it doesn't appear to be something
> that was "applied" (even accidentally) by user/use. it didn't
> wipe clean with mild detergent and water. Or alcohol.
>
> [I was reluctant to try more aggressive solvents for fear of
> damaging items that I don't own!]
>
> So, I spent the day digging through piles of kit at one of
> the non-profits with which I'm affiliated. And, managed to
> find an assortment of similarly "sticky" surfaces (some that
> see human contact, others that are NOT intended to see contact!)
>
> I've found these to have a coating (?) that is responsible
> for the stickiness. And, that the coating appears to *develop*
> this stickiness -- it's not present in all instances of an object
> (age?).
>
> With a LITTLE elbow grease and alcohol, I am able to remove the
> coating and expose the "solid plastic" beneath. The stickiness
> disappears with the coating's removal.
>
> I recall having problems with "rubber" feet disintegrating
> on various devices (e.g., all of my Sun enclosures now have
> self-adhesive *felt* feet as a precaution against their
> original feet turning to GOO and damaging the finish of the
> bits of furniture on which they reside).
>
> And, prompted by today's exercise, I noticed that the "rubber"
> button to operate my electric toothbrush is becoming "sticky";
> as if losing its chemical integrity.
>
> I assume these other "sticky" items have a fine coat of a
> similar substance applied to their HARD PLASTIC surfaces...
> for "feel"?
>
> So:
> - what causes this?
> - is there anything to prevent it's occurrence?
> - why would manufacturers go this route if this was an expected outcome?
> - are there other alternatives to alter feel/appearance without such
> applications? (mild textures?)

Although most of the items are black, I fine that talcum powder works
well to stop the stickiness. It leaves a sort of pale grey surface, but
it's ok by me. You might have to repeat it after a month or two.

I don't know what causes it. Oxygen might contribute to the surface
decomposition, but I don't think it's UV light as I've found it on a
memory stick kept in a box. If it's inherent decomposition, I doubt that
anything will stop it.

--

Jeff

On Wed, 7 Jun 2023 09:42:50 +0100, Martin Brown wrote:

> On 07/06/2023 06:39, Don Y wrote:
>>
>> I assume these other "sticky" items have a fine coat of a similar
>> substance applied to their HARD PLASTIC surfaces...
>> for "feel"?
>>
>> So:
>> - what causes this?
>> - is there anything to prevent it's occurrence?
>> - why would manufacturers go this route if this was an expected
>> outcome?
>> - are there other alternatives to alter feel/appearance without such
>>   applications?   (mild textures?)
>
> It is an intrinsic mode of failure of soft PVC or rubber.
>
> UV and ozone will do for them. The least bad option is to clean it off
> with the right solvent which for the things I had was brake fluid.
>
> TBH I only tried it because I happened to have some lying around and a
> horribly tacky Psion 3C that was unusable as a result of its tacky
> surfaces. Someone recommended it on the Internet - I didn't really
> expect it to work but to my amazement it did and required much less
> elbow grease than any of the other methods I had tried.

Not all soft plastics experience the 'sticky surface' failure mode. I
have only seen this failure on soft PVC made with cheap plasticizers.
Polyolefins, neoprene, silicone, polyurethane - I have never seen the
sticky surface failure on these or many others, even after decades of
exposure causing other failures.

Not all soft flexible PVC develops this failure either. While the cheap
clear PVC tubing bought at the local hardware store will, Tygon medical
grade clear flexible PVC tubing does not, even after decades. The
difference is cheap vs expensive plasticizers. (PVC without plasticizers
is rigid.)

I always associate the sticky surface failure with manufacturers who put
cost cutting ahead of quality, and try to avoid them in the future.

On 6/7/23 1:39 AM, Don Y wrote:
> The most important ergonomic design criteria that my
> testers report is "wipe clean" -- for all exposed surfaces
> (appliances, controls, etc.).
>
> OK, that puts limits on the types of textured surfaces that
> can be used -- but that's not unsurmountable.
>
> I heard lots of complaints of hand-held/operated devices that
> "feel sticky" after a while.  I had assumed this was just a
> buildup of oils/dirt from hands, easily addressed if the surface
> was designed for ease of cleaning (many devices have silly nooks
> and crannies that are often unnecessary or cosmetic).
>
> But, I've heard from several people that many devices *can't* be
> cleaned.  Or, more exactly, that cleaning doesn't remove the
> "stickiness".  (?)
>
> I received a couple of such samples in the past week and
> they *are* sticky.  And, it doesn't appear to be something
> that was "applied" (even accidentally) by user/use.  it didn't
> wipe clean with mild detergent and water.  Or alcohol.
>
> [I was reluctant to try more aggressive solvents for fear of
> damaging items that I don't own!]
>
> So, I spent the day digging through piles of kit at one of
> the non-profits with which I'm affiliated.  And, managed to
> find an assortment of similarly "sticky" surfaces (some that
> see human contact, others that are NOT intended to see contact!)
>
> I've found these to have a coating (?) that is responsible
> for the stickiness.  And, that the coating appears to *develop*
> this stickiness -- it's not present in all instances of an object
> (age?).
>
> With a LITTLE elbow grease and alcohol, I am able to remove the
> coating and expose the "solid plastic" beneath.  The stickiness
> disappears with the coating's removal.
>
> I recall having problems with "rubber" feet disintegrating
> on various devices (e.g., all of my Sun enclosures now have
> self-adhesive *felt* feet as a precaution against their
> original feet turning to GOO and damaging the finish of the
> bits of furniture on which they reside).
>
> And, prompted by today's exercise, I noticed that the "rubber"
> button to operate my electric toothbrush is becoming "sticky";
> as if losing its chemical integrity.
>
> I assume these other "sticky" items have a fine coat of a
> similar substance applied to their HARD PLASTIC surfaces...
> for "feel"?
>
> So:
> - what causes this?
> - is there anything to prevent it's occurrence?
> - why would manufacturers go this route if this was an expected outcome?
> - are there other alternatives to alter feel/appearance without such
>   applications?   (mild textures?)
>
>

It's a combination of decomposition of the main polymer, driven by some
combination of heat, humidity, and UV light, plus the migration to the
surface of whatever plasticizers, fire retardants, and stabilizers that
were mixed into the polymer to improve the polymer properties, plus all
of their breakdown products. Very soft, flexible "PVC" can be over 40%
additives and after a few years will steadily ooze "stickyness". You
can often find some detergeant or solvent or combination that will clean
the surface but once it starts it will always return, it's just a matter
of time. Besides speeding up the chemical decomposition reactions, heat
drives the diffusion to the surface so cold storage is always better, at
least to the point of frozen brittleness :-). Welcome to the world of
disposable products.

--
Regards,
Carl

Glen Walpert <nospam@null.void> Wrote in message:r
> On Wed, 7 Jun 2023 09:42:50 +0100, Martin Brown wrote:> On 07/06/2023 06:39, Don Y wrote:>> >> I assume these other "sticky" items have a fine coat of a similar>> substance applied to their HARD PLASTIC surfaces...>> for "feel"?>> >> So:>> - what causes this?>> - is there anything to prevent it's occurrence?>> - why would manufacturers go this route if this was an expected>> outcome?>> - are there other alternatives to alter feel/appearance without such>> applications? (mild textures?)> > It is an intrinsic mode of failure of soft PVC or rubber.> > UV and ozone will do for them. The least bad option is to clean it off> with the right solvent which for the things I had was brake fluid.> > TBH I only tried it because I happened to have some lying around and a> horribly tacky Psion 3C that was unusable as a result of its tacky> surfaces. Someone recommended it on the Internet - I didn't really> expect it to work but to my amazement it did and required much less> elbow grease than any of the other methods I had tried.Not all soft plastics experience the 'sticky surface' failure mode. I have only seen this failure on soft PVC made with cheap plasticizers. Polyolefins, neoprene
, silicone, polyurethane - I have never seen the sticky surface failure on these or many others, even after decades of exposure causing other failures.Not all soft flexible PVC develops this failure either. While the cheap clear PVC tubing bought at the local hardware store will, Tygon medical grade clear flexible PVC tubing does not, even after decades. The difference is cheap vs expensive plasticizers. (PVC without plasticizers is rigid.)I always associate the sticky surface failure with manufacturers who put cost cutting ahead of quality, and try to avoid them in the future.

Its Ozone that breaks down the rubber.
My spare tire brace covering in my truck suffered from this, I
didn't know at the time I grabbed it like a hand rail, I had a
hand full of black goo as a result.

I know of no way to recover it, just clean with alchohol, and replace.
Apparently it's in how the rubber is formulated.

Cheers
--

----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html

On 6/7/2023 10:58, Anthony William Sloman wrote:
> On Wednesday, June 7, 2023 at 3:39:26 PM UTC+10, Don Y wrote:
>
> Rubber is polyisoprene.
>
> https://en.wikipedia.org/wiki/Polyisoprene
>
> Expose it to air, and the double bonds on the surface get attacked by oxygen (ozone works faster) and it isn't a polymer any more.
>
> Scrub the surface hard enough and presumably you can scrub off the damaged layer.
>

Do you have an idea what causes the rubber tv remotes are
made of release something oily after some year(s) of use?

I don't but I have found a remedy; washing with some gasoline,
a small brush (meant for artists, nonetheless I own some :) to
get to holes etc. revives the thing (the pcb also gets washed,
obviously, it is all covered by oil).

On Tue, 6 Jun 2023 22:39:12 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

>The most important ergonomic design criteria that my
>testers report is "wipe clean" -- for all exposed surfaces
>(appliances, controls, etc.).
>
>OK, that puts limits on the types of textured surfaces that
>can be used -- but that's not unsurmountable.
>
>I heard lots of complaints of hand-held/operated devices that
>"feel sticky" after a while. I had assumed this was just a
>buildup of oils/dirt from hands, easily addressed if the surface
>was designed for ease of cleaning (many devices have silly nooks
>and crannies that are often unnecessary or cosmetic).
>
>But, I've heard from several people that many devices *can't* be
>cleaned. Or, more exactly, that cleaning doesn't remove the
>"stickiness". (?)
>
>I received a couple of such samples in the past week and
>they *are* sticky. And, it doesn't appear to be something
>that was "applied" (even accidentally) by user/use. it didn't
>wipe clean with mild detergent and water. Or alcohol.
>
>[I was reluctant to try more aggressive solvents for fear of
>damaging items that I don't own!]
>
>So, I spent the day digging through piles of kit at one of
>the non-profits with which I'm affiliated. And, managed to
>find an assortment of similarly "sticky" surfaces (some that
>see human contact, others that are NOT intended to see contact!)
>
>I've found these to have a coating (?) that is responsible
>for the stickiness. And, that the coating appears to *develop*
>this stickiness -- it's not present in all instances of an object
>(age?).
>
>With a LITTLE elbow grease and alcohol, I am able to remove the
>coating and expose the "solid plastic" beneath. The stickiness
>disappears with the coating's removal.
>
>I recall having problems with "rubber" feet disintegrating
>on various devices (e.g., all of my Sun enclosures now have
>self-adhesive *felt* feet as a precaution against their
>original feet turning to GOO and damaging the finish of the
>bits of furniture on which they reside).
>
>And, prompted by today's exercise, I noticed that the "rubber"
>button to operate my electric toothbrush is becoming "sticky";
>as if losing its chemical integrity.
>
>I assume these other "sticky" items have a fine coat of a
>similar substance applied to their HARD PLASTIC surfaces...
>for "feel"?
>
>So:
>- what causes this?
>- is there anything to prevent it's occurrence?
>- why would manufacturers go this route if this was an expected outcome?
>- are there other alternatives to alter feel/appearance without such
> applications? (mild textures?)
>

Very likely the "rubber" is urethane-based , and is depolymerizing.

This is called reversion, as in the rubber polymer reverts back to the
monomer from which it was made.

Joe Gwinn

El 07/06/2023 a las 18:21, Dimiter_Popoff escribió:
> On 6/7/2023 10:58, Anthony William Sloman wrote:
>> On Wednesday, June 7, 2023 at 3:39:26 PM UTC+10, Don Y wrote:
>>
>> Rubber is polyisoprene.
>>
>> https://en.wikipedia.org/wiki/Polyisoprene
>>
>> Expose it to air, and the double bonds on the surface get attacked by
>> oxygen (ozone works faster) and it isn't a polymer any more.
>>
>> Scrub the surface hard enough and presumably you can scrub off the
>> damaged layer.
>>
>
> Do you have an idea what causes the rubber tv remotes are
> made of release something oily after some year(s) of use?
>
> I don't but I have found a remedy; washing with some gasoline,
> a small brush (meant for artists, nonetheless I own some :) to
> get to holes etc. revives the thing (the pcb also gets washed,
> obviously, it is all covered by oil).

It is silicone grease, caused by defective curating of the membrane.
Ethanol and cotton are very effective.

--
Saludos
Miguel Gimenez

On 6/7/2023 1:52 AM, Jeff Layman wrote:
>> And, prompted by today's exercise, I noticed that the "rubber"
>> button to operate my electric toothbrush is becoming "sticky";
>> as if losing its chemical integrity.
>>
>> I assume these other "sticky" items have a fine coat of a
>> similar substance applied to their HARD PLASTIC surfaces...
>> for "feel"?
>>
>> So:
>> - what causes this?
>> - is there anything to prevent it's occurrence?
>> - why would manufacturers go this route if this was an expected outcome?
>> - are there other alternatives to alter feel/appearance without such
>>     applications?   (mild textures?)
>
> Although most of the items are black, I fine that talcum powder works well to
> stop the stickiness. It leaves a sort of pale grey surface, but it's ok by me.
> You might have to repeat it after a month or two.

"Why would manufacturers go this route it this was an expected outcome?"

Surely, there are other materials and finishes that could be used.
Is <whatever> less expensive than the plastic onto which it is *applied*
(these look like COATINGS with the thickness of a fine layer of paint;
yet are quite obviously not part of the underlying material to which
they were applied)

I.e., what ADVANTAGE to this approach?

[It may, in fact, just be a "spray on MATTE finish" to avoid having
to acid etch a mold for "texture"]

The "rubber" (rubbery?) button on my electric toothbrush shows this
degradation -- but the similar material that totally surrounds the
device doesn't. Either a different material (?) or different
use pattern? (my hand spends more time in contact with the material
surrounding the device than it does with the on/off button)

> I don't know what causes it. Oxygen might contribute to the surface
> decomposition, but I don't think it's UV light as I've found it on a memory
> stick kept in a box. If it's inherent decomposition, I doubt that anything will
> stop it.

On Wednesday, June 7, 2023 at 4:42:58 AM UTC-4, Martin Brown wrote:
> On 07/06/2023 06:39, Don Y wrote:

> > I heard lots of complaints of hand-held/operated devices that
> > "feel sticky" after a while. I had assumed this was just a
> > buildup of oils/dirt from hands, easily addressed if the surface
> > was designed for ease of cleaning (many devices have silly nooks
> > and crannies that are often unnecessary or cosmetic).
> >
> > But, I've heard from several people that many devices *can't* be
> > cleaned. Or, more exactly, that cleaning doesn't remove the
> > "stickiness". (?)

> I have found that amazingly to me that brake fluid is remarkably good at
> removing the depolymerised short chain polymer tack from such objects.
> It may also alter the surface texture too if it takes too much off.

Alcohol, glycerine, and brake fluid (which is mainly a heavy alcohol)
all work. Isopropanol is volatile enough that you can't wipe it on
and let it sit, but have to rub vigorously to clean.

> > With a LITTLE elbow grease and alcohol, I am able to remove the
> > coating and expose the "solid plastic" beneath. The stickiness
> > disappears with the coating's removal.

But with some items, may recur.

On 6/7/2023 1:42 AM, Martin Brown wrote:
> On 07/06/2023 06:39, Don Y wrote:
>> But, I've heard from several people that many devices *can't* be
>> cleaned.  Or, more exactly, that cleaning doesn't remove the
>> "stickiness".  (?)
>>
>> I received a couple of such samples in the past week and
>> they *are* sticky.  And, it doesn't appear to be something
>> that was "applied" (even accidentally) by user/use.  it didn't
>> wipe clean with mild detergent and water.  Or alcohol.
>>
>> [I was reluctant to try more aggressive solvents for fear of
>> damaging items that I don't own!]
>
> I have found that amazingly to me that brake fluid is remarkably good at
> removing the depolymerised short chain polymer tack from such objects. It may
> also alter the surface texture too if it takes too much off.

Yikes! Brake fluid will take the paint off metal! :-/

> Test any such solvent on a small patch out of sight and see if it works for you
> before risking it on the visible exposed parts.

I have a go-to list of solvents that I use, based on the material
being removed (and past experiences with it or similar) AND the
underlying material. E.g., I will clean glass with more aggressive
solvents than I would use on plastics.

In (general) order:
- soapy water (dissolves may glues used for labels)
- alcohol
- mineral spirits
- WD-40 (et al.)
- gasoline
- acetone, mek, xylene (et al.)
- mechanical abrasion (e.g., rotary wire brush)

> Basically a combination of ozone and UV exposure degrades these soft rubbery
> polymer and short chain stuff is horribly tacky. The hard polymers tend to be
> more aggressively crosslinked and seldom fail this way but in extreme
> environments they become brittle and craze instead.

I'm not sure THIS is "rubber". In the past, my experiences have been
with "rubbery" substances... things that were large enough that you could
actually apply pressure and see (intended) deformation -- like "feet"
for devices.

These instances appear to be surface coatings. They tend to alter the
appearance of what would otherwise be "glossy" plastic parts. There
MAY be a slight change to the feel imparted but nothing that you
would think of as "rubbery" (in terms of deformability).

E.g., I noticed the logo on some of my GPUs is presented on a surface
that has a similar treatment; I can't imagine it's purpose, there,
would be to alter the *feel* of the PCI card. And, it doesn't affect
the item structurally as the cards are supported with deliberate
mechanical devices -- not logos! :>

>> So, I spent the day digging through piles of kit at one of
>> the non-profits with which I'm affiliated.  And, managed to
>> find an assortment of similarly "sticky" surfaces (some that
>> see human contact, others that are NOT intended to see contact!)
>>
>> I've found these to have a coating (?) that is responsible
>> for the stickiness.  And, that the coating appears to *develop*
>> this stickiness -- it's not present in all instances of an object
>> (age?).
>>
>> With a LITTLE elbow grease and alcohol, I am able to remove the
>> coating and expose the "solid plastic" beneath.  The stickiness
>> disappears with the coating's removal.
>>
>> I recall having problems with "rubber" feet disintegrating
>> on various devices (e.g., all of my Sun enclosures now have
>> self-adhesive *felt* feet as a precaution against their
>> original feet turning to GOO and damaging the finish of the
>> bits of furniture on which they reside).
>>
>> And, prompted by today's exercise, I noticed that the "rubber"
>> button to operate my electric toothbrush is becoming "sticky";
>> as if losing its chemical integrity.
>>
>> I assume these other "sticky" items have a fine coat of a
>> similar substance applied to their HARD PLASTIC surfaces...
>> for "feel"?
>>
>> So:
>> - what causes this?
>> - is there anything to prevent it's occurrence?
>> - why would manufacturers go this route if this was an expected outcome?
>> - are there other alternatives to alter feel/appearance without such
>>    applications?   (mild textures?)
>
> It is an intrinsic mode of failure of soft PVC or rubber.

Is this, then, just a different application of those BEYOND use
as "feet"? If so, why not some other substance (or PROCESS)
to achieve the same *visuals*/feel?

> UV and ozone will do for them. The least bad option is to clean it off with the
> right solvent which for the things I had was brake fluid.

We use a lot of (recycled) glass containers/jars for storage as they
aren't oxygen permeable. A quick soak dissolves paper labels allowing
them to be scratched off with a fingernail. The glue residue coming off
with a mild mechanical abrasive or mineral spirits (later washed with
alcohol and then soapy water before being used for foodstuffs).

"Property (inventory) tags" are most often encountered affixed to
metal surfaces so gentle prying (many are made of metal themselves)
followed by spirits or acetone (if the surface isn't painted).

Many solvents will take the "gloss" off of plastics. Likewise, vigorous
rubbing. This makes the resulting surface look "used".

> TBH I only tried it because I happened to have some lying around and a horribly
> tacky Psion 3C that was unusable as a result of its tacky surfaces. Someone
> recommended it on the Internet - I didn't really expect it to work but to my
> amazement it did and required much less elbow grease than any of the other
> methods I had tried.

But, will the "condition" return?

"Why would manufacturers go this route if this was an expected outcome?"

On 6/7/2023 3:08 PM, whit3rd wrote:
> On Wednesday, June 7, 2023 at 4:42:58 AM UTC-4, Martin Brown wrote:
>> On 07/06/2023 06:39, Don Y wrote:
>
>>> I heard lots of complaints of hand-held/operated devices that
>>> "feel sticky" after a while. I had assumed this was just a
>>> buildup of oils/dirt from hands, easily addressed if the surface
>>> was designed for ease of cleaning (many devices have silly nooks
>>> and crannies that are often unnecessary or cosmetic).
>>>
>>> But, I've heard from several people that many devices *can't* be
>>> cleaned. Or, more exactly, that cleaning doesn't remove the
>>> "stickiness". (?)
>
>> I have found that amazingly to me that brake fluid is remarkably good at
>> removing the depolymerised short chain polymer tack from such objects.
>> It may also alter the surface texture too if it takes too much off.
>
> Alcohol, glycerine, and brake fluid (which is mainly a heavy alcohol)
> all work. Isopropanol is volatile enough that you can't wipe it on
> and let it sit, but have to rub vigorously to clean.
>
>>> With a LITTLE elbow grease and alcohol, I am able to remove the
>>> coating and expose the "solid plastic" beneath. The stickiness
>>> disappears with the coating's removal.
>
> But with some items, may recur.

I "cleaned" a mouse with such a coating -- by removing the coating!
Now, the mouse has a *glossy* plastic finish instead of a *matte* one.
I'd be hard pressed to identify which had the coating (prior to the
stickiness phase) and which didn't, based solely on feel.

I don't expect to ever need to "clean" it again.

IMO, the manufacturer could have textured his molds to give a similar
appearance/feel to the mouse without the "risk" of this silly coating.
Or, the recurring cost for the material applied.

On 6/7/2023 5:18 AM, Glen Walpert wrote:
> On Wed, 7 Jun 2023 09:42:50 +0100, Martin Brown wrote:
>
>> On 07/06/2023 06:39, Don Y wrote:
>>>
>>> I assume these other "sticky" items have a fine coat of a similar
>>> substance applied to their HARD PLASTIC surfaces...
>>> for "feel"?
>>>
>>> So:
>>> - what causes this?
>>> - is there anything to prevent it's occurrence?
>>> - why would manufacturers go this route if this was an expected
>>> outcome?
>>> - are there other alternatives to alter feel/appearance without such
>>>   applications?   (mild textures?)
>>
>> It is an intrinsic mode of failure of soft PVC or rubber.
>>
>> UV and ozone will do for them. The least bad option is to clean it off
>> with the right solvent which for the things I had was brake fluid.
>>
>> TBH I only tried it because I happened to have some lying around and a
>> horribly tacky Psion 3C that was unusable as a result of its tacky
>> surfaces. Someone recommended it on the Internet - I didn't really
>> expect it to work but to my amazement it did and required much less
>> elbow grease than any of the other methods I had tried.
>
> Not all soft plastics experience the 'sticky surface' failure mode. I
> have only seen this failure on soft PVC made with cheap plasticizers.
> Polyolefins, neoprene, silicone, polyurethane - I have never seen the
> sticky surface failure on these or many others, even after decades of
> exposure causing other failures.

It's not always a "surface" phenomenon. E.g., the feet on Sun workstations
turn into a gooey substance that makes used chewing-gum-in-the-hot-sun
look like a trivial mess to clean, by comparison!

And, would surface *coatings* be of similar composition? Are there
alternatives (regardless of cost)?

> Not all soft flexible PVC develops this failure either. While the cheap
> clear PVC tubing bought at the local hardware store will, Tygon medical
> grade clear flexible PVC tubing does not, even after decades. The
> difference is cheap vs expensive plasticizers. (PVC without plasticizers
> is rigid.)
>
> I always associate the sticky surface failure with manufacturers who put
> cost cutting ahead of quality, and try to avoid them in the future.

How do you ascertain whether a product is *coated* with a material
that might degrade thusly? Do you assume manufacturers never
improve their products/processes?

E.g., an nVidia GPU used a similar material/coating. Ditto a MS mouse.
I don't see a rationale for *either* to have made these choices, except,
perhaps, ignorance of the long-term consequences of their choices.

[I want to skip forward to that point where this outcome does not apply]

On 6/7/2023 6:30 AM, Carl wrote:
> On 6/7/23 1:39 AM, Don Y wrote:
>> The most important ergonomic design criteria that my
>> testers report is "wipe clean" -- for all exposed surfaces
>> (appliances, controls, etc.).
>>
>> OK, that puts limits on the types of textured surfaces that
>> can be used -- but that's not unsurmountable.

>> I've found these to have a coating (?) that is responsible
>> for the stickiness.  And, that the coating appears to *develop*
>> this stickiness -- it's not present in all instances of an object
>> (age?).

>> I recall having problems with "rubber" feet disintegrating
>> on various devices (e.g., all of my Sun enclosures now have
>> self-adhesive *felt* feet as a precaution against their
>> original feet turning to GOO and damaging the finish of the
>> bits of furniture on which they reside).
>>
>> And, prompted by today's exercise, I noticed that the "rubber"
>> button to operate my electric toothbrush is becoming "sticky";
>> as if losing its chemical integrity.
>>
>> I assume these other "sticky" items have a fine coat of a
>> similar substance applied to their HARD PLASTIC surfaces...
>> for "feel"?
>>
>> So:
>> - what causes this?
>> - is there anything to prevent it's occurrence?
>> - why would manufacturers go this route if this was an expected outcome?
>> - are there other alternatives to alter feel/appearance without such
>>    applications?   (mild textures?)
>
> It's a combination of decomposition of the main polymer, driven by some
> combination of heat, humidity, and UV light, plus the migration to the surface
> of whatever plasticizers, fire retardants, and stabilizers that were mixed into
> the polymer to improve the polymer properties, plus all of their breakdown
> products.  Very soft, flexible "PVC" can be over 40% additives and after a few
> years will steadily ooze "stickyness".

Would something "soft (fluid) enough" to be applied as a *coating*
be such an example? Or, is this a different substance, entirely?

> You can often find some detergeant or
> solvent or combination that will clean the surface but once it starts it will
> always return, it's just a matter of time.  Besides speeding up the chemical
> decomposition reactions, heat drives the diffusion to the surface so cold
> storage is always better, at least to the point of frozen brittleness :-).
> Welcome to the world of disposable products.

The point of my question is not to "fix" devices that I have that
are exhibiting this problem. Rather, to make sure I don't *design*
devices that will exhibit it!

You wouldn't KNOWINGLY put knobs on a device that would "become
sticky" with age.

I.e., the "why would manufacturers go this route if this was an
expected outcome?" especially if "other alternatives to alter
feel/appearance without such applications" exist. How many
micropennies do you have to spend to avoid this problem? Or,
is it unavoidable -- that <whatever> reason the manufacturers are
chosing to go this route can only be addressed *by* this technique?

On 6/7/2023 10:19 AM, Joe Gwinn wrote:
> Very likely the "rubber" is urethane-based , and is depolymerizing.

So, all urethane-derived products/materials/coatings would exhibit a similar
problem?

Are there alternatives to these?

> This is called reversion, as in the rubber polymer reverts back to the
> monomer from which it was made.
>
> Joe Gwinn

On 07/06/2023 23:47, Don Y wrote:
> On 6/7/2023 3:08 PM, whit3rd wrote:
>> On Wednesday, June 7, 2023 at 4:42:58 AM UTC-4, Martin Brown wrote:
>>> On 07/06/2023 06:39, Don Y wrote:
>>
>>>> With a LITTLE elbow grease and alcohol, I am able to remove the
>>>> coating and expose the "solid plastic" beneath.  The stickiness
>>>> disappears with the coating's removal.
>>
>> But with some items, may recur.
>
> I "cleaned" a mouse with such a coating -- by removing the coating!
> Now, the mouse has a *glossy* plastic finish instead of a *matte* one.
> I'd be hard pressed to identify which had the coating (prior to the
> stickiness phase) and which didn't, based solely on feel.
>
> I don't expect to ever need to "clean" it again.

If you have removed the offending surface layer then that is probably
the case. Most things that have this stuff on usually have an MTBF that
is broadly comparable with the failure of the soft rubbery plastics.

> IMO, the manufacturer could have textured his molds to give a similar
> appearance/feel to the mouse without the "risk" of this silly coating.
> Or, the recurring cost for the material applied.

That sort of soft fleshy feel was in for a while. Manufacturers adopted
it without worrying about the cheap plasticisers allowing polymer
degradation on a ~5-10 year timescale depending on ozone levels.

Most kit is replaced on a shorter timescale and so it is non-problem.
(for the manufacturers)

--
Martin Brown

On 07/06/2023 23:41, Don Y wrote:
> On 6/7/2023 1:42 AM, Martin Brown wrote:

>> Basically a combination of ozone and UV exposure degrades these soft
>> rubbery polymer and short chain stuff is horribly tacky. The hard
>> polymers tend to be more aggressively crosslinked and seldom fail this
>> way but in extreme environments they become brittle and craze instead.
>
> I'm not sure THIS is "rubber".  In the past, my experiences have been
> with "rubbery" substances... things that were large enough that you could
> actually apply pressure and see (intended) deformation -- like "feet"
> for devices.

I'm using rubber here in the generic properties sense including anything
plastic that is slightly soft to the touch as opposed to strongly
crosslinked and rigid engineering plastics.

> These instances appear to be surface coatings.  They tend to alter the
> appearance of what would otherwise be "glossy" plastic parts.  There
> MAY be a slight change to the feel imparted but nothing that you
> would think of as "rubbery" (in terms of deformability).
>
> E.g., I noticed the logo on some of my GPUs is presented on a surface
> that has a similar treatment; I can't imagine it's purpose, there,
> would be to alter the *feel* of the PCI card.  And, it doesn't affect
> the item structurally as the cards are supported with deliberate
> mechanical devices -- not logos!  :>

Some paints are very similar formulations.
>>> So:
>>> - what causes this?
>>> - is there anything to prevent it's occurrence?
>>> - why would manufacturers go this route if this was an expected outcome?
>>> - are there other alternatives to alter feel/appearance without such
>>>    applications?   (mild textures?)
>>
>> It is an intrinsic mode of failure of soft PVC or rubber.
>
> Is this, then, just a different application of those BEYOND use
> as "feet"?  If so, why not some other substance (or PROCESS)
> to achieve the same *visuals*/feel?
>
>> UV and ozone will do for them. The least bad option is to clean it off
>> with the right solvent which for the things I had was brake fluid.
>
> We use a lot of (recycled) glass containers/jars for storage as they
> aren't oxygen permeable.  A quick soak dissolves paper labels allowing
> them to be scratched off with a fingernail.  The glue residue coming off
> with a mild mechanical abrasive or mineral spirits (later washed with
> alcohol and then soapy water before being used for foodstuffs).
>
> "Property (inventory) tags" are most often encountered affixed to
> metal surfaces so gentle prying (many are made of metal themselves)
> followed by spirits or acetone (if the surface isn't painted).
>
> Many solvents will take the "gloss" off of plastics.  Likewise, vigorous
> rubbing.  This makes the resulting surface look "used".
>
>> TBH I only tried it because I happened to have some lying around and a
>> horribly tacky Psion 3C that was unusable as a result of its tacky
>> surfaces. Someone recommended it on the Internet - I didn't really
>> expect it to work but to my amazement it did and required much less
>> elbow grease than any of the other methods I had tried.
>
> But, will the "condition" return?
>
> "Why would manufacturers go this route if this was an expected outcome?"

It almost never fails within the period of warrantee. Marketing types
seem to like the soft touch feel of the rubbery plastics. I never really
liked it - dead flesh style waterproof keyboards put me off for life!

--
Martin Brown

On 08/06/2023 01:53, Don Y wrote:
> On 6/7/2023 6:30 AM, Carl wrote:

>> You can often find some detergeant or solvent or combination that will
>> clean the surface but once it starts it will always return, it's just
>> a matter of time.  Besides speeding up the chemical decomposition
>> reactions, heat drives the diffusion to the surface so cold storage is
>> always better, at least to the point of frozen brittleness :-).
>> Welcome to the world of disposable products.
>
> The point of my question is not to "fix" devices that I have that
> are exhibiting this problem.  Rather, to make sure I don't *design*
> devices that will exhibit it!
>
> You wouldn't KNOWINGLY put knobs on a device that would "become
> sticky" with age.

Because they want the customer to buy another one every 6-8 years and
they expect many to have failed or be replaced before the surface
coating even becomes an issue. Hotter, or humidity, and high UV all
accelerate the damage to softer plastics.

Better plasticisers can make it last much longer but in most cases price
is everything and so you get what you pay for.

--
Martin Brown

On 6/8/2023 2:22 AM, Martin Brown wrote:
> On 07/06/2023 23:47, Don Y wrote:
>> On 6/7/2023 3:08 PM, whit3rd wrote:
>>> On Wednesday, June 7, 2023 at 4:42:58 AM UTC-4, Martin Brown wrote:
>>>> On 07/06/2023 06:39, Don Y wrote:
>>>
>>>>> With a LITTLE elbow grease and alcohol, I am able to remove the
>>>>> coating and expose the "solid plastic" beneath.  The stickiness
>>>>> disappears with the coating's removal.
>>>
>>> But with some items, may recur.
>>
>> I "cleaned" a mouse with such a coating -- by removing the coating!
>> Now, the mouse has a *glossy* plastic finish instead of a *matte* one.
>> I'd be hard pressed to identify which had the coating (prior to the
>> stickiness phase) and which didn't, based solely on feel.
>>
>> I don't expect to ever need to "clean" it again.
>
> If you have removed the offending surface layer then that is probably the case.
> Most things that have this stuff on usually have an MTBF that is broadly
> comparable with the failure of the soft rubbery plastics.

Dunno. This was so *thin* that I suspect it was sprayed on. As I was
removing it, you could visually see the point of demarcation between the
coated/uncoated surfaces. But, would be hard-pressed to feel/measure
any difference in thickness.

>> IMO, the manufacturer could have textured his molds to give a similar
>> appearance/feel to the mouse without the "risk" of this silly coating.
>> Or, the recurring cost for the material applied.
>
> That sort of soft fleshy feel was in for a while. Manufacturers adopted it
> without worrying about the cheap plasticisers allowing polymer degradation on a
> ~5-10 year timescale depending on ozone levels.

I'm sure "fleshy" wasn't the goal as the coating had no real "body" to it.
If you squeezed the item and another "uncoated" item, you'd feel no
difference.

It *may* have imparted a texture (rough vs. smooth). Or, it may have been
for visual characteristics (matte vs. glossy).

E.g., I have found a similar substance on the logo for some of my GPUs.
No thickness to it. And, I don't see how it would add much value in
terms of "feel" -- do you often stroke your PCI cards?

> Most kit is replaced on a shorter timescale and so it is non-problem.
> (for the manufacturers)

I'm looking at relatively long service lives -- a decade or more.
So, wonder what the goal of applying these "coatings" may have been.
Were they trying to make an otherwise smooth surface appear to have
some slight texture (in which case, why not just texture the mold
and have that texture baked into the plastic?)? Or, was it a
visual issue just to take the sheen off of a smooth, glossy part?
(again, why not texture the mold and save the step of having to
apply a coating?)

*Or*, will I discover some other consequence of having removed the
coating that isn't as easily addressed with, for example, a textured
mold?

Don Y <blockedofcourse@foo.invalid> wrote:
> On 6/8/2023 2:22 AM, Martin Brown wrote:
>> Most kit is replaced on a shorter timescale and so it is
>> non-problem. (for the manufacturers)
>
> I'm looking at relatively long service lives -- a decade or more.

Which is where your viewpoint diverges from the manufacturer. From the
manufacturer viewpoint, too long of a service life is a negative,
because that does not drive the "sales treadmill" if existing kit can
continue to be used vs. being replaced with new kit (which also means a
new *sale* to the manufacturer).

> So, wonder what the goal of applying these "coatings" may have been.

You'd have to ask the manufacturer to know for sure. But one very
likely scenario is:

The designers, in order to justify their continued paychecks, must make
changes on a continual basis. Those same changes (i.e., applying this
'coating') are aesthetic rather than functional, but because of a change,
some percentage of existing customers will be incentivized to replace
their existing device with a new device (thereby driving the sales
treadmill) solely on the aesthetic change alone.

The manufacturer is not concerned with a decade or more of service
life. Often their only concern is sufficient lifetime such that
warranty service is minimized (time X), and just long enough that existing
customers are not encouraged to switch to a different maker's brand
because "our" brand is perceived as "cheap-ass Chinese junk" (time Y).

Therefore, the aesthetic coating dreamed up by the designers goes on
(for generating the "aesthetic sales") and even if the manufacturer has
tested it for a lifetime estimate, if they find it degrades sometime
shortly beyond "time Y" then so much the better, because that will
drive the sales treadmill some more as items begin becoming "sticky"
after "time Y" has elapsed, encouraging even more owners to "buy a new
one" (as few will bother trying to "clean off the stickiness").

On Wed, 7 Jun 2023 17:54:38 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

>On 6/7/2023 10:19 AM, Joe Gwinn wrote:
>> Very likely the "rubber" is urethane-based, and is depolymerizing.
>>
>> This is called reversion, as in the rubber polymer reverts back to the
>> monomer from which it was made.
>
>So, all urethane-derived products/materials/coatings would exhibit a similar
>problem?

Depends on the specific urethane chemistry chosen by the manufacturer.

>Are there alternatives to these?

Yes, there are grades of urethane rubber that are reversion-resistant,
and will so claim in datasheets.

For instance:

..<https://www.matweb.com/search/datasheet.aspx?matguid=a22d1756842a4a55b7843f54b6ceb8bb&ckck=1>

Joe Gwinn

On 6/8/2023 3:13 AM, Martin Brown wrote:
>> These instances appear to be surface coatings.  They tend to alter the
>> appearance of what would otherwise be "glossy" plastic parts.  There
>> MAY be a slight change to the feel imparted but nothing that you
>> would think of as "rubbery" (in terms of deformability).
>>
>> E.g., I noticed the logo on some of my GPUs is presented on a surface
>> that has a similar treatment; I can't imagine it's purpose, there,
>> would be to alter the *feel* of the PCI card.  And, it doesn't affect
>> the item structurally as the cards are supported with deliberate
>> mechanical devices -- not logos!  :>
>
> Some paints are very similar formulations.

Then that would lend cred to it being used for visual properties.
I.e., AS paint.

>>> TBH I only tried it because I happened to have some lying around and a
>>> horribly tacky Psion 3C that was unusable as a result of its tacky surfaces.
>>> Someone recommended it on the Internet - I didn't really expect it to work
>>> but to my amazement it did and required much less elbow grease than any of
>>> the other methods I had tried.
>>
>> But, will the "condition" return?
>>
>> "Why would manufacturers go this route if this was an expected outcome?"
>
> It almost never fails within the period of warrantee.

Well, part of the design process is to target a service life (hence my
concern for these "failures" and why they were chosen for application)

> Marketing types seem to
> like the soft touch feel of the rubbery plastics. I never really liked it -
> dead flesh style waterproof keyboards put me off for life!

Again, these seem to have no real "feel" beyond noting that a given weight
of silk feels smoother than denim.

I can understand their use in (cheap) elastomeric buttons (e.g., on
Ir remote controls). And, I can understand wanting the electric toothbrush
to NOT feel hard and unyielding in your hand as you wave it around the inside
of your mouth.

But, I see little value to a coating on a (e.g.) mouse that doesn't
do much more than change it's appearance. Or, on a GPU... (you're
going to look at the GPU only until the point where you install it
in your computer; thereafter, you wouldn't know if it turned bright
PINK when out of view!)

Don Y <blockedofcourse@foo.invalid> wrote:
> On 6/8/2023 3:13 AM, Martin Brown wrote:
>> It almost never fails within the period of warrantee.
>
> Well, part of the design process is to target a service life (hence
> my concern for these "failures" and why they were chosen for
> application)

To an Engineer, yes. To a marketer, no. For a marketer, the service
life should be just long enough to not cause excessive warranty returns
during the warranty period, with no more life beyond that. Because to
a marketer, every item that fails X delta outside the warranty is
viewed as driving a "new sale" of a "new, replacement, unit".

> But, I see little value to a coating on a (e.g.) mouse that doesn't
> do much more than change it's appearance. Or, on a GPU... (you're
> going to look at the GPU only until the point where you install it in
> your computer; thereafter, you wouldn't know if it turned bright PINK
> when out of view!)

Again you are thinking like an Engineer, instead of as a marketer.
From the marketing department's viewpoint, any change in appearance
that is also inexpensive will drive additional sales. The reason is
that a majority of customers are not Engineers, and for that large
group of customers, any small change in appearance will drive some
percentage of them to buy a new model, even if they just bought the
prior model a short time ago. So the *value* in this coating on a
mouse is: "X percent of customers will buy the new model with the new
coating within Y months of beginning sale of the new model, and the
coating adds only $0.0005 to the BOM". This keeps the sales treadmill
running.

Martin Brown <'''newspam'''@nonad.co.uk> wrote:

> It almost never fails within the period of warrantee. Marketing types
> seem to like the soft touch feel of the rubbery plastics. I never really
> liked it - dead flesh style waterproof keyboards put me off for life!
> Martin Brown
The Kensington K64406US USB/PS2 Washable Keyboard is like a standard keyboard
but is completely washable. This means dust and lint cannot enter the keys
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--
MRM