"thixotropic" resin
"thixotropic" resin
(OP)
Can anyone explain the meaning of this term?
thx
thx
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RE: "thixotropic" resin
RE: "thixotropic" resin
I can understand the fluid like property is good for resin penetration and the egel like property is good for resin retention.
Very briefly, how is the fluid-like property activited during the vpi process?
RE: "thixotropic" resin
RE: "thixotropic" resin
http://www.dolphs.com/techtips_600.cfm
I believe this is for random wound machines (where there tend to be larger voids to fill), not form-wound where my experience is mainly with Epoxylite 347. This becomes very much less viscous at elevated temperature (it is introduced into the VPI tank at about 60deg C), I don't know if thixotropic resins do likewise. Incidentally, one way of keeping non-thixotropic resins in the winding after VPI is to rotate cure.
RE: "thixotropic" resin
RE: "thixotropic" resin
We utilize a thixotropic resin here to contain crossover junctions on a PMDC motor and as stated by UKpete, the material is highly viscous at room temp, but becomes very much less at the cure temperature allowing for high wicking properties.
RE: "thixotropic" resin
http://www.fpchem.com/fap_6a1-en.html
for: How to produce thixotropic resins
RE: "thixotropic" resin
Thixotropic-High and low viscosity with the same resin.
Low viscosity after agitated penetrates multiple layers of mica tape.
High viscosity at rest, with complete encapsulation.
Very expensive epoxy resin, but worth every drop, it must be good stuff if the Navy uses it...
Kind Regards
motorhead
RE: "thixotropic" resin
http://www.dolphs.com/pdfs/Dol_VPI_Chart.pdf
etc. for more info
RE: "thixotropic" resin
Immediately after mixing, transfer the resin to the vacuum chamber, allowing it to flow up from the bottom of the chamber to cover the unit by a depth of at least 1" Maintain vacuum for 60 minutes. Release vacuum and apply pressure of 90 to 100 psi for 30 minutes and release pressure. Remove the unit slowly from the resin. A rate of 4" per minute is recommended. Cure in bake oven at 300f for 8-10 hours for maximum resin retention and encapsulation....
RE: "thixotropic" resin
RE: "thixotropic" resin
What I've noticed with non-thixotropic resins is that in the oven the resin initially goes through a very low-viscosity stage before it starts to gel, and this is when a lot of run-off occurs. I guess there is better retention with the thixotropic resin.
RE: "thixotropic" resin
kind regards
motorhead
RE: "thixotropic" resin
http://www.acmanet.org/pressreleases/press-release40.cf...
for: Increasing statistics for thixotropic resins
http://www.coatings.de/articles/ecspapers/bakker/bakker...
for: New thixotropic alkyd resin family based on polyamide technology
etc. for more info