Sciencemadness Discussion Board

Delayed 'Delivery'

encipher - 9-5-2007 at 17:05

Hi,

Anyone ever buy those capsules that you toss in your bathtub, dissolve, and deliver bath oils into the water. Well, I'm looking to make a similar thing, I want to have a salt (granular), or concentrated solution of the salt in one of those capsules, and have a delayed delivery into the water as the capsule or bead dissolves.

Does anyone have experience with these, or any idea on where to start with making them?

Thanks

ssdd - 10-5-2007 at 02:09

Could you perhaps use a gelatin type thing where you mix the salt with the gelatin then pour it into a mold?

Not sure how well that would work, but I know it would dissolve in hot water slowly, also not sure how high a concentration of salt you could get into it, I have gotten pretty high concentrations of sugar in the past. What the exact ratios were I couldn't tell you.

roamingnome - 10-5-2007 at 06:58

http://www.aveka.com/aveka_beads.htm

i got free samples from a company simmilar to this for a skateboard wax invention

its easier to put nonpolar oils inside capsules

its seems in your case the capsule size would need to be larger.

the last time i used gelitan it dried too slowly and formed crust every where.

encipher - 10-5-2007 at 10:38

yeah, I'm looking for a much larger size. About the size of a AAA battery. Any ideas?

roamingnome - 10-5-2007 at 11:16

http://www.spicediscounters.com/gelcap000.jpg

http://www.kalyx.com/store/images/capa.jpg


000 triple zero is the largest they make....

not_important - 10-5-2007 at 11:50

The usual way solids are package for bath use, or for other delayed release, is to compress the solids into pellets; possibly adding small amounts of starch or other soft material that will dissolve or disperse in water. Sometimes the pellets or tablets then get a thin coating of a agent to slow the initial contact with water.

Materials which can be used to slow down solution in water, or to form a slowly dissolving film, include polyvinyl alcohol (PVA), polyethylene oxide (PEG - long chain polywthylene glycol), agar, alginic acid, carrageenan, and the gums xanthan, locus bean, guar, arabic, gellan, and carboxymethyl cellulose (CMC). Some of these interact with polyvalent ions, and so might not be suitable for you application. Some can be made up in hot solutions, possibly with alcohol, that rapidly thicken as it cools, this would allow dipping or tumbling to form a surface film.

As these are complex substances or mixtures, getting the right variant isn't always easy, especially for individuals. Fabricating containers, such as those gelcaps, isn't simple either.

You might be able to find PVA in the form of small bags; or tubing of the right diameter, PVA is a thermoplastic, you can heat seal tubing to form small packets - seal one end, add powder, seal above that to finish one and start the next pouch, cut them apart when done.