If I'm understanding Peter Brothers' posts, and Richard Hess's, then the prediction is that the 
Richardson tape will eventually go back to sticky, because there will be hydrolysis taking place in 
the binder that holds what's left of the tape together. Is this correct?

-- Tom Fine

----- Original Message ----- 
From: "Corey Bailey" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 22, 2016 2:21 AM
Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson treated tape


> Hi Richard,
>
> Charlie Richardson's assertion (as I understand it) is that the back-coating, introduced to reduce 
> static buildup, absorbs humidity by design. Being in contact with each adjacent layer of the 
> oxide, the humidity absorbing back-coating promotes binder hydrolysis.
>
> Fascinating thread. Thanks to all who have contributed.
>
> Cheers!
>
> Corey
> Corey Bailey Audio Engineering
>
> On 1/21/2016 5:52 PM, Richard L. Hess wrote:
>> On 1/21/2016 7:55 PM, Tom Fine wrote:
>>> And this once again circles back to one of my main questions -- if
>>> sticky shed is due to problems with the binder, then why would removing
>>> the back-coat seem to first of all make a tape un-sticky and second keep
>>> it un-sticky for a long period of time, if not permanently?
>>
>> Hi, Tom,
>>
>> This is a VERY good question that I have asked myself (and others) for many years. No one except 
>> Richardson blames the back-coating.
>>
>> So, here is one thought I have had about this. I am not saying that the chemistry is the same, 
>> but I'm saying it MIGHT be a similar effect.
>>
>> Do you recall how vinyl sheet protectors will weld to electrostatic copier printing and pull it 
>> off? There is something in the vinyl that is attacking the electrostatic "ink" which is really 
>> plastic which is melted onto the paper. So, it appears to be a plastic-to-plastic reaction.
>>
>> OK, we have plastic binder on the front and plastic binder on the back in touch with each other. 
>> Could a similar reaction be occurring?
>>
>> Here is a complicating factor and a possible alternate explanation to the above conjecture. I 
>> believe the carbon black in the back coating is highly hygroscopic so it can act as a moisture 
>> concentrator that slurps moisture from the edge of the tape pack and wicks it across the full 
>> width. That moisture then accelerates the hydrolysis of the binder.
>>
>> But accelerates is different than starts. Well, I'm sure you've noticed some tapes when wiped 
>> have degradation products and/or dirt coming off just at the edges? Without the carbon black to 
>> wick the moisture into the pack, perhaps the edges degrade first?
>>
>> Now, this conjecture raises another issue and that is what type of a reaction is binder 
>> hydrolysis? Is it a linear no threshold reaction or is there a threshold of moisture below which 
>> hydrolysis will not occur.
>>
>> This is similar to ionizing radiation where study upon study shows that up to a point radiation 
>> is actually beneficial and then becomes harmful. Some scientists are saying the government 
>> mandated linear no threshold model for radiation is flawed and wastes huge sums of money.
>>
>> I realize one is chemical and one is biological, but still, some reactions need a catalyst to 
>> start or keep going.
>>
>> There is more here that we don't understand (on both counts).
>>
>> So, here is a post full of thinking out loud, but why not? If it triggers someone who cares and 
>> has access to an analytical lab and funding, perhaps it might go some place. Better to throw it 
>> out there.
>>
>> Remember, do not rely on anything I said in this message. Use it only as a basis for further 
>> analysis. I do not know what's true. I know what I'd want to check out given a white coat, 
>> glassware, and other things I have no real knowledge of. My last chem class was Grade 11. I did 
>> well and enjoyed it, but that was a long time ago.
>>
>> Cheers,
>>
>> Richard
>>
>
>