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I love Kleenex Cool Touch tissues. I'm just wondering what makes them actually feel cool. For some reason it makes me think of refrigerant but I'm sure that's not in them.

Is it the combination of common ingredients that somehow gives it a moist feel, making it feel cooler than normal tissues?

Are the tissues safe to put to your face, if you are potentially inhaling the ingredient(s)?

Ingredients: Stearyl heptanoate, stearyl alcohol, polyethylene, mineral oil, coconut oil, aloe

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It's definitely safe, yes. All of the ingredients you've listed above are non-toxic. Aloe verra is often used to cool burning areas (though it's treatment is questionable). –  Jeremy Jan 4 '13 at 4:58
    
Stearyl alcohol make it cool to touch. Because alcohol evaporates easily. It is safe to use. –  lambda23 Jan 4 '13 at 6:23
    
@lambda23: It makes sense that evaporation would make the cool-to-touch feeling, but by that logic, by the next day all of the alcohol would be gone. Are you sure that's right? –  Jeremy Jan 4 '13 at 6:36
    
@lambda23: Maybe body heat warms up the stearyl alcohol which is what causes it to evaporate. I don't have access to a Cool Touch tissue right now, but maybe the OP does. OP: Try touching the whole tissue for so long that it's not cold anymore. Then come back and do it again. And again. And again. See if it ever stops feeling cold. –  Jeremy Jan 4 '13 at 6:44
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@lambda23 - Consult the liquid range of stearyl alcohol and you will find it is a solid at room temperature and has a boiling point of 210 C. Not the best candidate for evaporative cooling... –  Richard Terrett Jan 4 '13 at 11:32

1 Answer 1

up vote 2 down vote accepted

My first guess as to the nature of this behaviour is similar to water. Hypothermia is a realistic risk if you are drenched in water. This is because water can absorb large amounts of energy (it has a large specific heat capacity) to only rise in temperature slightly. Water itself evaporates into steam spontaneously, if some water is spilled then it will evaporate readily, regardless of the temperature. Likewise, the solids in the tissue are probably coming closer to melting temperature, which I believe is higher than your body temperature, but quickly absorbing a lot of energy from your body in the process.

Something similar to properties of water are probably characteristic to the tissue. Leave the tissue in the open in a cool room, along with a glass of water. After awhile, touching the glass of water and the tissue should invoke the same sense of coolness. This is because your body is at a higher temperature than the items in the room.

There is likely another property of matter besides specific heat capacity that is a measurement of how quickly heat is transferred, this is likely to play a role as well. I do not know what this property is called and it was never covered in my classes so far, but take metal for example. Metal has a very small specific heat capacity, it can not hold much energy. However, touching a metal object invokes a sense of coolness. I believe this is because heat is transferred very quickly through metal, although it warms very quickly due to its limited heat capacity. If you put a metal cup and a porcelain cup on the stove, the metal will burn you much quicker if you grab it than grabbing the porcelain/ceramic cup.

If you were very interested and inquistive you could test the specific heat of the tissue through experimentation. Also, try holding the napkin for a few seconds to try and find out how quickly the tissue warms to the touch. Chances are, it warms relatively fast and can absorb a lot of energy, giving you the impression that it is 'cooler' than most objects, to which marketers will be overwrought with the joy of hearing.

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Saying "how quickly heat is transferred" is incorrect. Heat is the transfer of energy. –  Jeremy Jan 4 '13 at 17:55
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@Nile en.wikipedia.org/wiki/Heat_transfer "Heat ...and is synonymous with heat flow and heat transfer. –  sencer Jan 4 '13 at 19:31
    
@sencer Reading the heat wikipedia page, "Heat ... is synonymous with heat flow and heat transfer." Sorry, I stand corrected. –  Jeremy Jan 4 '13 at 19:35
    
@sencer: I see you've updated your post. Just as an FYI, it doesn't say that on the link you've sent. It says that on en.wikipedia.org/wiki/Heat –  Jeremy Jan 4 '13 at 22:20
    
@Nile yes, sorry. It doesn't let me fix it. –  sencer Jan 5 '13 at 19:00

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