Polyurthane Infill Material

[bafometto81]

Hi Everybody,

I am a materials engineer and I work as coating engineer for oil & gas industry.
I was attenting a qualification test for solid polyurethane infill material for field joint coating and I experimented a quite strange behaviour of the material.
After filling the mould around the pipe,the solid PU started to flow from the the injection hole of the mould.
Does anybody have an idea how toexplain this bahviour?¿

Thanks

Nicolò Bovo
website:

http://www.saipem.it

 

[berkshire]

bafometto81 (Petroleum)
Are you sure you did not have any moisture present in the joint.
The presence of moisture can cause some 2 part urethane's to foam a little.
B.E.

 

[bafometto81]

Berkshire,

I alo thought on moisutre, but before starting the infill operations the joint was pre-heated at 30º, so moisture shouldn't be present.
Do you think that a density test could be useful?

Thanks

Nicolò

 

[berkshire]

bafometto81 (Petroleum)
I am not that familiar with your process, is the mold removed after the urethane is cured?
If it is a visual inspection would indicate if any foaming took place, it would show up as slight porosity in the part.
The other factor that would cause material to flow from the sprue hole would be expansion of the material caused by an exothermic reaction as the PU cured.
B.E.