[georgeau]

currently working on a small project. I pour abrasive grain and phenolic resin in a drum to form a mixture, there is a spray gun being used on top of the drum which used to suck up the mixture and spray the mixture on the surface of a testing surface, however, the abrasive grain SINK onto the bottom before the mixture spray outs, end up with "not enough" grain mixture..

any solution?

[cth]

Can you simply keep the constituents separated and mix them at the last moment inside the spray gun? There would be no sedimentation problem anymore.

If not possible, I think you will need nanometer size grains and a surfactant in order to form a colloidal solution.

[georgeau]

Can you simply keep the constituents separated and mix them at the last moment inside the spray gun? There would be no sedimentation problem anymore.

If not possible, I think you will need nanometer size grains and a surfactant in order to form a colloidal solution.

thanks, i will try to obtain nanometer size aluminum oxide samples...can you suggest the kind of surfactant that is useful in my case?

[cth]

I would go for some fatty acids http://en.wikipedia.org/wiki/Fatty_acid with a long hydrocarbon chain.
The type of surfactant to use depends on the nature of the resin and it is commercially availability.

[georgeau]

thanks so much for advice.

how about aerosol ?
Can you message me your email so that we could talk thoroughly?

[eugenedakin]

Hello georgeau,

Another possible solution is to increase the Low Shear Rate Viscosity (LSRV). This can be accomplished by adding a small amount of Xanthan Gum. This will allow the small particles to remain suspended for a long period of time (over a few days). It is important that the LSRV be increased and not the High Shear Rate Viscosity (HSRV). The HSRV (such as addition of clays) will probably not suspend the larger particles.

The only problem with increasing the viscosity, is that your application requires spraying the material. You may require a larger jet-nozzle to spray the more viscous liquid.

I hope this helps,

Eugene

[georgeau]

I would go for some fatty acids http://en.wikipedia.org/wiki/Fatty_acid with a long hydrocarbon chain.
The type of surfactant to use depends on the nature of the resin and it is commercially availability.

I have emailed directly to your email address, wonder if you have received it.
Thanks

[georgeau]

Thanks all,

The liquid phenolic resin i was using have following specification:
Solid 60-64 %  (135 degre celcius x 60mins)
Viscocity 80-200 (cps)  (25 degree celcius Brookfield)
water tolerance 2000 (%)  (25 degree celcius)
pH 9.2 - 10.0
-->filler used: Gypsum powder


Another liquid phenolic resin will be used have following spec (not tested yet):
Solid 72-76 %  (135 degre celcius x 60mins)
Viscocity(#G)  U - W   (25 degree celcius Gardner)
MeOH tolerance(%) 160min   (25 degree celcius)
Gel Time(min)   10 - 20   (130 degree celcius oil bath)

[georgeau]

any idea?

[georgeau]

finally find a special spray gun for my test...thanks all. anyone interested to know the spray gun may leave me a message.

[student77]

Hi,as I understood, You found special gun to spray such mixture,
I am wondering- where it is possible to get this gun and how it looks ?
Would You be so kind and share such information ?

Thanks & regards
student77