An alternative look at ink wetness

[Lithium466]

3 hours ago, txomsy said:

* Not mixing acidic with basic inks is one case to remember: they will form salts and my end clogging your pen (usually not immediately, but in the long run, they may); or not using strongly reactive alkaline inks (e.g. BSB) with susceptibly reactive negatively charged plastics (e.g. some sacs/feeds): they may dissolve (like dissolves like), again, usually not immediately (there may always be extreme exceptions), but in the long run, they may. If in doubt, or if you prefer to err on the cautious side, then, please, stick to safe inks.

I don't want to highjack the thread, but is BSB really strongly alkaline? I remember seeing it measured at PH 4,4, but I can't find the source anymore.

Then there's that thread:

 

[txomsy]

Well, I do not know id 'strongly' is the correct word, but my understanding is that all the Baystate inks are alkaline, which is why they should not be mixed with other non-Baystate inks.

 

[ferrogallic]

Thanks for the sketch, @LizEF!!! Very interesting discussion.

 

7 hours ago, InesF said:

Oh, my! 😱 Indeed, I didn't read carefully and three times I read xanthane and not xanthate. Sorry, for my sloppiness!

 

The substance with the structure formula as shown must have a negative RedOx potential. Means: it will react with oxygen (maybe catalysed by metal surfaces) and it will, most probably, react with the usual dyes of fountain pen inks. When it was/is used as described in the paper of the Chinese scientists, its application was optimized for metal extraction (building complexes with multivalent metals, dissolving them from minerals).

Whatever the solutions of this substance do with surface tension and/or viscosity is meaningless (and useless) for fountain pen inks because of its reactivity and because of its toxicity.

This is also the first time I came across these salts, I don't think they are common outside of the mining industry. These molecules don't dissolve metals, but selectively change the surface energy of ores (e.g. sulfides, metals). E.g. you'd like to separate gold from rock. Normally both are gold and ore are similarly wetted by water. The Flotation agent makes the gold not wet, so that little air bubbles can attach to it and float the gold to the surface. I think there are some agents that work the opposite way as well.
 

https://www.911metallurgist.com/blog/flotation

 

Quote

 

So far no satisfactory explanation of flotation phenomena has been advanced. At my instigation and under my direction, a large amount of research work has been done in an earnest endeavor to formulate some logical explanation, and perhaps to find some scientific way of conducting experiments in lieu of the empirical methods now in vogue. While this purpose has not yet been fully attained, the experiments have resulted in the formulation of a theory that appears to be well grounded and that may prove of value to others engaged in this branch of metallurgy.

Much work has been done at the Mellen Institute at Pittsburg under the direction of Raymond C. Bacon, and lately by James A. Block at the local station of the U. S. Bureau of Mines. The results of some of this work are summarized in the following statements:

In considering the connection between flotation phenomena and the physical properties of the minerals concerned, there are two parallelisms to be noticed:

First: It has been noticed for some time that the minerals which floated were not easily wetted by water, while those which were easily wetted did not tend to come up with the froth. This is the basis of about the only theory that has been widely circulated up to this time. It is well stated by Hoover in his book, ‘Concentrating Ores by Flotation,’ the first authoritative publication on the subject.

 

 

 

I personally would be careful with the potassium amyl xanthate. Supposedly it is not very toxic (LD₅₀ is 90-148 mg/kg oral, rat, according to Wikipedia), but I recently read a disturbing book about what CS₂ can do to to humans ("Fake Silk, The Lethal History of Viscose Rayon"), so I'd be extremely wary about anything similar. Maybe it doesn't decompose into CS₂, it's really just a guess.

The phosphorodithioate is non-toxic, according to the manufacturer. Also it is stable in a wider pH range.

 

What I find fascinating about the patent is that it gives us another knob to turn, in a direction that I naively would not have expected:

It allows reducing the "wetness" of the ink without affecting the other properties.

 

These are some of the knobs:

1. Surfactants: Change surface tension for all materials similarly
   • Make the nib "wetter"
   • Make ink start more easily and soak into the paper more quickly
   • Increase feathering
   • Can only reduce surface tension, not increase it (ok, a little bit, with lots of salt)
   • Dyes can also act as surfactants
2. Flotation agents: Similar to a surfactant, but only reacts with the metal in the nib
   • Increase surface angle, i.e. increase apparent surface tension of the ink on the nib
   • Make nib "dryer" without affecting other properties of ink
   • Might work in the other direction as well and increase wetness of nib
3. Colloids: Starch, gum arabic
   • Don't affect flow, unless used in very high concentrations
   • Reduce feathering
4. Flow enhancers
   • Bentonite clay
   • Not clear how it works, might break up droplets or improve wetting of the feed
5. pH
   • This is a complicated one, as @txomsy explained
   • The mystery patent chose high pH because it a) soaks into the paper quickly and b) allows to use permanent metal dyes (maybe phthalocyanines?).
   • At high pH the ink will react with the cellulose fibers. This is probably the reason the ink is called fast drying.
6. Organic solvents like glycerin, glycols etc.
   • Make ink dry more slowly on the nib, but still soak into paper quickly
   • Reduce surface tension

 

So if we had the compound, we could add surfactants to the ink to make them soak into the paper quickly, suppress feathering by adding a colloid, and then still make the ink dry by modifying the nib-ink interface.

[txomsy]

That sounds to me like a pretty good summary. Thanks, I am always wary of using technical terms which makes my posts so convoluted. You are far better at this than I am.

[LizEF]

4 hours ago, ferrogallic said:

Thanks for the sketch, @LizEF!!!

You're welcome - it was the only way I could contribute anything.  You scientists left the rest of us behind several pages ago!  (Please, don't stop!)

[InesF]

23 hours ago, inkstainedruth said:

[...] so I ended up having chemistry at the end of the day, in a class that only had two other girls in it, and a lot of the boys had just gotten out of gym so they were all sweaty and gross....  Plus the chemistry teacher was a jerk....

I can well understand that the "after gym" situation is unfavorable - what a pity. And if the teacher is a jerk, not much can be gained from the course. Quite often single persons can motivate or demotivate all of their students for a certain topic.

The situation was not so much different for me. I was horribly demotivated for languages (and had to learn English later all by myself) but was enthraled for physics and chemistry already in secondary school. Later we were three girls among 25 boys in chemistry high school - it was more often funny and rarely frustrating ...  

[InesF]

4 hours ago, ferrogallic said:

These are some of the knobs:

1. Surfactants: Change surface tension for all materials similarly
   • Make the nib "wetter"
   • Make ink start more easily and soak into the paper more quickly
   • Increase feathering
   • Can only reduce surface tension, not increase it (ok, a little bit, with lots of salt)
   • Dyes can also act as surfactants
2. Flotation agents: Similar to a surfactant, but only reacts with the metal in the nib
   • Increase surface angle, i.e. increase apparent surface tension of the ink on the nib
   • Make nib "dryer" without affecting other properties of ink
   • Might work in the other direction as well and increase wetness of nib
3. Colloids: Starch, gum arabic
   • Don't affect flow, unless used in very high concentrations
   • Reduce feathering
4. Flow enhancers
   • Bentonite clay
   • Not clear how it works, might break up droplets or improve wetting of the feed
5. pH
   • This is a complicated one, as @txomsy explained
   • The mystery patent chose high pH because it a) soaks into the paper quickly and b) allows to use permanent metal dyes (maybe phthalocyanines?).
   • At high pH the ink will react with the cellulose fibers. This is probably the reason the ink is called fast drying.
6. Organic solvents like glycerin, glycols etc.
   • Make ink dry more slowly on the nib, but still soak into paper quickly
   • Reduce surface tension

 

@ferrogallic, I like your summary in general.

However, there are some misconceptions.

1.4. Using surfactants and salt is contra productive. Better use only one of them if you like to set the surface tension. And no, surfactants can increase the surface tension when the solution contains, for example anionic surfactants and you add cationic surfactants to it. Or vice versa.

1.5. Consider the same principle as in 1.4

2. I would not rely on the "reacts only". No, I would not. And, especially, do not forget about the interaction of the ink with the paper.

3. Thickening agents are extremely different. G.A. is a weak thickener and you need, indeed, roughly 0.5% or more to have a visible effect for an ink. But there are others which increase viscosity at lower concentrations. Why are they not used frequently? Because of a) they are expensive and b) dosage is very difficult.

4. I'm not sure if bentonite clay can act as flow enhancer and I would never recommend it for use in fountain pens.

5. You are, in most cases not completely free to set the pH of an ink to any value. Consider, there is a dye (the core element of an ink) that is, most probably, pH dependent in solubility and in colour!

 

This is no offense. It is important to be aware about the very common situation that a certain principle that works for one application (ore separation) may not be the way to go for another (fountain pen ink).

 

And reading (almost) all the information in the references leaves one question unanswered to me: if the xanthate flotation principle for ore was patented in the early 1900's and was claimed to be the most effective and cheapest, why is it neither investigated more deeply and why not used in big scale during the last 120 years?

However, no answer necessary, because this is a fountain pen ink and not a mining thread.

 

Be aware, I love your excitement and willingness to experiment with ink property customisation and can only emphasize you to continue with practical experiments. I'm looking forward to the further progress!

[ferrogallic]

@InesF good points, I agree with points 1-5. The bentonite is a mystery, which I've never read about before, it's from the same strange patent.

 

Quote

The flow of the ink may be fur= ther improved by the addition of colloidal clays such as the bentonites. We prefer for our inks to use a special highly colloidal bentonite known to the trade as Wilkinite. This clay when used in amounts as small as .2 of 1% seems to have some favorable effect on the flow of the ink from certain types of fountain pens.

Bentonite is cheaply available in many drugstores as a food supplement or for skin cleansing. I wouldn't put it in an expensive pen.

 

 

If you saw my post on old irongall recipes, there is a funny story when it was accidentally left out of the official government specification after they placed an order, so the Bureau of Standards was tasked with finding a solution. Ultimately they found the ink is better without. For this reason I've never used gum arabic in my inks, but I understand that it is a pretty complex hydrocolloid that might affect feathering in other ways than through viscosity. It also acts as a surfactant.

 

 

22 hours ago, InesF said:

And reading (almost) all the information in the references leaves one question unanswered to me: if the xanthate flotation principle for ore was patented in the early 1900's and was claimed to be the most effective and cheapest, why is it neither investigated more deeply and why not used in big scale during the last 120 years?

However, no answer necessary, because this is a fountain pen ink and not a mining thread.

 

They are used on a huge scale, entire landscapes are contaminated with mining effluents, they are dirt cheap, you can buy 900kg for $1870. Typically they go under trade names, like AERO 350, or abbreviations (PAX, SEX, SAX, SIPX, SIBX). PAX is the one from the patent.

 

The assignee of the patent is Parker, so I don't think the patent is bogus. My suspicion is that it is the foundation of the (in)famous Superchrome inks.

 

I found two less interesting patents that might be for dyes for these inks.

https://patents.google.com/patent/US2489463A/en

https://patents.google.com/patent/US2528390A/en

 

Are these alkaline inks better than today's inks? I don't know. In the 40s and 50s pens were made out of natural rubber, nitrocellulose, latex sacs, maybe carbon steel parts, so I wouldn't be surprised if they were damaged by a strongly alkaline ink (at least they often had gold nibs). Maybe that's why these inks never took off. Also, pens were traditionally made to withstand highly acidic irongall inks. Today's polymers and steels are much better, so I don't see any issues in modern pens. Like @txomsy said, most inks are designed for normal pens, while Parker could optimize for their own pens. Also, many common dyes work better at low pH. As we see from the patents, they also had issues finding dyes that are stable at high pH.

 

I am definitely intrigued by the flotation ingredients. Like I mentioned, the xanthates are not harmless, and will most likely form highly toxic products at low pH.

On the other hand, there are hundreds of other flotation helpers, but I don't know where to start, or how to get my hands on them. The phosphorodithioate looks promising, and would be stable in regular inks, but I don't know how to get it.

 

Overall, I doubt most inks are optimized, it's such a niche product, and the manufacturers probably don't have access to much chemical expertise either. The perfect ink is still out there to be developed!

 

If anyone here knows any mining engineers, please do ask them about flotation agents!

[InesF]

12 hours ago, ferrogallic said:

Overall, I doubt most inks are optimized, it's such a niche product, and the manufacturers probably don't have access to much chemical expertise either. The perfect ink is still out there to be developed!

Ah, I would extend your statement into: "There are ink manufacturers that know very well what they are doing! Besides them, some others have empirically formulated ink recipes that worked somehow by chance. It is, sometimes, on us fountain pen users to identify which ink is produced by which type of manufacturer."

 

You can see it as adventure, as challenge, as gamble or you simply don't care and become a ballpoint user again. 🤫

[Sholom]

On 10/31/2023 at 3:40 PM, ferrogallic said:

@InesF good points, I agree with points 1-5. The bentonite is a mystery, which I've never read about before, it's from the same strange patent.

 

Bentonite is cheaply available in many drugstores as a food supplement or for skin cleansing. I wouldn't put it in an expensive pen.

 

 

If you saw my post on old irongall recipes, there is a funny story when it was accidentally left out of the official government specification after they placed an order, so the Bureau of Standards was tasked with finding a solution. Ultimately they found the ink is better without. For this reason I've never used gum arabic in my inks, but I understand that it is a pretty complex hydrocolloid that might affect feathering in other ways than through viscosity. It also acts as a surfactant.

 

 

 

They are used on a huge scale, entire landscapes are contaminated with mining effluents, they are dirt cheap, you can buy 900kg for $1870. Typically they go under trade names, like AERO 350, or abbreviations (PAX, SEX, SAX, SIPX, SIBX). PAX is the one from the patent.

 

The assignee of the patent is Parker, so I don't think the patent is bogus. My suspicion is that it is the foundation of the (in)famous Superchrome inks.

 

I found two less interesting patents that might be for dyes for these inks.

https://patents.google.com/patent/US2489463A/en

https://patents.google.com/patent/US2528390A/en

 

Are these alkaline inks better than today's inks? I don't know. In the 40s and 50s pens were made out of natural rubber, nitrocellulose, latex sacs, maybe carbon steel parts, so I wouldn't be surprised if they were damaged by a strongly alkaline ink (at least they often had gold nibs). Maybe that's why these inks never took off. Also, pens were traditionally made to withstand highly acidic irongall inks. Today's polymers and steels are much better, so I don't see any issues in modern pens. Like @txomsy said, most inks are designed for normal pens, while Parker could optimize for their own pens. Also, many common dyes work better at low pH. As we see from the patents, they also had issues finding dyes that are stable at high pH.

 

I am definitely intrigued by the flotation ingredients. Like I mentioned, the xanthates are not harmless, and will most likely form highly toxic products at low pH.

On the other hand, there are hundreds of other flotation helpers, but I don't know where to start, or how to get my hands on them. The phosphorodithioate looks promising, and would be stable in regular inks, but I don't know how to get it.

 

Overall, I doubt most inks are optimized, it's such a niche product, and the manufacturers probably don't have access to much chemical expertise either. The perfect ink is still out there to be developed!

 

If anyone here knows any mining engineers, please do ask them about flotation agents!

It was always my understanding that the Superchrome inks were distinctly alkaline and that was supposed to help them penetrate (heavily sized??) paper faster so that they would appear to be quicker drying. The two patents probably do relate to Superchrome inks and in particular the blue inks. There were only a limited number of blue dyes that didn't have either long-term stability problems in the alkaline inks. The brightest blues at that time were particularly prone to light-induced fading (e.g. the Victoria Blue family). The sulfonated copper phthalocyanine dyes mentioned in the second patent would have been the obvious choice for color purity and light and chemical resistance but as the patent disclosed, traces of copper from their manufactures were deadly for rubber sacs and probably hard rubber pens as well. The first patent thus proposes a new family of dyes that would hopefully be brighter and inherently copper-free, while the second patent addresses chemicals that should tie up the traces of copper and keep them from degrading the sacs. I have no information on whether either type of blue dye in these patents was actually used by Parker then or now.

[InesF]

Thank you, @Sholom, for your deep dive into ink patents. 

There're highly interesting details about vintage inks and how people tried to overcome something I would call the character of ink. At least for me, writing with fountain pens is so special because I can see the wet line appearing while the nib glides over the paper. If I need an instantly dry line I always use a ballpoint (which is about 2 or 3 times a year). All inks I use on all types of paper usually dry in less than 20 seconds (sorry, @LizEF). Why even try to change the base character of writing with fountain pens?

 

And finally, almost off-topic here, there are more than 2000 fountain pen inks available. I'm confident, everybody can find the one which combines the preferred colour with preferred properties. And if that isn't enough, flitter, lubricants, thickening agents or detergents (be careful, it's sooo easy to ruin a good ink) and even water can be added for full satisfaction. We are living in the Golden Age of fountain pen inks!

[LizEF]

6 hours ago, InesF said:

All inks I use on all types of paper usually dry in less than 20 seconds (sorry, @LizEF).

 

6 hours ago, InesF said:

Why even try to change the base character of writing with fountain pens?

Exactly!  You may as well choose a different writing implement.  There's no shortage of those to choose from, each with their own unique characteristics.

 

6 hours ago, InesF said:

We are living in the Golden Age of fountain pen inks!

Amen to that!  A poor reviewer can never hope to keep up with all the ink brands, never mind the individual inks!  We're up to our eyeballs in ink!

[Puddinhead]

On 10/29/2023 at 2:03 PM, LizEF said:

My sentiments Exactly!

[LizEF]

32 minutes ago, Puddinhead said:

My sentiments Exactly!

[txomsy]

I agree.

 

TL;DR:

 

Darn! These last comments made me revisit this thread! And a few key words made me rethink it.

 

Biophysics is a discipline I always found interesting.

 

Many problems mentioned here are familiar to medical doctors as they can be generalized and the effects seen in body fluid flow problems (think asthma or subclavian steal). Which took me to reflect on the basics and some extensions (like the effect of ionic bonding interactions between salt ions and surfactants) and a few extra effects not considered (like supersaturated solutions, nucleation effects/factors and flow --think kidney stones). It also led me to think of sepiolites and other mineral additives and their potential effects --which leads into crystallography (and some interesting effects in intestinal flow and animal farming). And in so doing a quick search for the formulas led me -thanks to Google's adaptive search engine- to the computational fluid dynamics models in use.

 

Now I can't stop thinking if one could take the amazing Montblanc X-ray pictures available here on FPN, build a 3D model and use a computer to model ink flow. And if some other MDs joined, I am sure they'd have most valuable insights.

 

Which takes me back to one dining table conversation I had once with several Chemistry Nobel laureates. I asked them about Computational Chemistry and they all agreed it was great to interpret results, but doubted it ever would be a match for experimenting: if you have a clear "qualitative" picture of the potentially undergoing processes, it was faster, easier and more effective to do the experiments than to build a "quantitative" theoretical model that you would still need to verify experimentally in the end.

 

That was some 12 years ago. Computers and models have gone a long way, Computational Chemistry also got a Nobel Prize, and in the Life and Health Sciences we still use computers to interpret results, but we are also using them very often now to screen hypotheses and plan directed experiments.

 

However, the principle still applies: even for knowledgeable companies, it would have been easier -and may still be- to proceed by experimentation than to be knowledge/model driven.

 

And for us, FP aficionados, it may be simpler to just try any hypothesis. Specially now that getting ultra-cheap pens for torture-testing is so easy and we do not need to put at risk our beloved and expensive pens.

 

[LizEF]

4 hours ago, txomsy said:

Biophysics is a discipline I always found interesting.

 

Many problems mentioned here are familiar to medical doctors as they can be generalized and the effects seen in body fluid flow problems (think asthma or subclavian steal). Which took me to reflect on the basics and some extensions (like the effect of ionic bonding interactions between salt ions and surfactants) and a few extra effects not considered (like supersaturated solutions, nucleation effects/factors and flow --think kidney stones). It also led me to think of sepiolites and other mineral additives and their potential effects --which leads into crystallography (and some interesting effects in intestinal flow and animal farming). And in so doing a quick search for the formulas led me -thanks to Google's adaptive search engine- to the computational fluid dynamics models in use.

 

Now I can't stop thinking if one could take the amazing Montblanc X-ray pictures available here on FPN, build a 3D model and use a computer to model ink flow. And if some other MDs joined, I am sure they'd have most valuable insights.

 

Which takes me back to one dining table conversation I had once with several Chemistry Nobel laureates. I asked them about Computational Chemistry and they all agreed it was great to interpret results, but doubted it ever would be a match for experimenting: if you have a clear "qualitative" picture of the potentially undergoing processes, it was faster, easier and more effective to do the experiments than to build a "quantitative" theoretical model that you would still need to verify experimentally in the end.

 

That was some 12 years ago. Computers and models have gone a long way, Computational Chemistry also got a Nobel Prize, and in the Life and Health Sciences we still use computers to interpret results, but we are also using them very often now to screen hypotheses and plan directed experiments.

 

However, the principle still applies: even for knowledgeable companies, it would have been easier -and may still be- to proceed by experimentation than to be knowledge/model driven.

That right up there ^^^ is why I write fiction.  The real world is just way, way too complicated!! (The older I get, the more I discover just how little I know.  It can be discouraging at times.  Then Klaw shows up and demands that I spend time waving around a feather on the end of a stick for him, and the universe shrinks to laughing at my silly kitty...)

[txomsy]

Intuition, when properly used, is a most powerful force.

 

And nothing nurtures it better than fooling around while enjoying life. Keep up your connection to the world and cherish it, and may you enjoy a Happy 2024.

[LizEF]

3 minutes ago, txomsy said:

Intuition, when properly used, is a most powerful force.

 

And nothing nurtures it better than fooling around while enjoying life. Keep up your connection to the world and cherish it, and may you enjoy a Happy 2024.

Thank you!  And you and yours, too, @txomsy!

[InesF]

There is an update of the ink properties table. Not much to tell, except the number of measured inks has grown to 121:

 

 

PS: 5 more inks arrived this week ....

[LizEF]

39 minutes ago, InesF said:

PS: 5 more inks arrived this week ....