I haven't been able to get 2-component Polyurethane to adhere to EPDM rubber. Does anybody know of a way of accomplishing this (additives or a primer)?
Some powder coatings are really tricky - I've had perfect adhesion going to complete release just by changing the color of the coating (the manufacturers claim the formulations are unchanged).
Try wiping the coated surface with some acetone and letting it dry for a few minutes before applying...
I would go for the vacuum-packing, hanging in the dark solution. You might not be able to counter all the ageing factors, so concentrate on the ones you can:
Tyres become brittle because of atmospheric attack by ozone, oxygen and even sulfides. Light is also bad, specially UV. Moisture or water...
I have seen salts which alter the conductivity of elastomers drastically, even in very small amounts. I don't remember exactly what they were, probably metal complexes. If i'm not mistaken Miliken (a pigment manufacturer) in Europe was doing some research on it.
Giacaglia
Hello BLN,
It is all a matter of weight and costs saving: with foams you use less polyurethane resin and the parts weigh less.
The foam is usually formed in place, not die cut, so it has a hydrophobic compact integral skin on all sides. Furthermore, if the foam is mostly composed of closed...
Why use silicone? There's no need for it unless you are so close to the engine or exhaust, that temperatures above 200-220°F are expected, and it's a very expensive material.
Many cable grommets are made of polyurethane foams or elastomers and are very resistant to cutting from sharp metal...
Your question is not an easy one. Polyurethane is the denomination for a whole class of polymers - typical foam formulations have 10 or more individual compounds. There isn't a "chemical to increase the hardness" of every foam formulation without knowing its composition, you have to...
This probably won't affect you, but there is another area of concern for silicone products: the engine components. Even minute amounts of silicone oils and polymers will burn and produce silica particles, which in turn clog the lambda sensor and shut down catalysts.
In general, there are a few...
It depends on what levels of conductivity you are expecting. The usual products of choice are polyurethane or epoxy resin with high levels of special fillers.
If you are in Europe try
www.bakelite.de,
www.rampf-resins.com
or www.wevo.de
Good Luck!
Roger
I do not know of any resin in particular, but I suspect a silicone primer which adheres in spite of the silicone oil will not present an adhesive surface itself either.
One alternative way to accomplish this would be to carry out plasma treatment of the surface (and in effect burning or blasting...
Hi Gerry,
look also for silicone-based adhesives (2-Component or 1-Component heat-cure, not moisture cure). As a rule of thumb, silicone adheres to silicone.
Hope this helps.
Roger
Hello Highspeed,
when designing polymers for dampening of noise and vibrations there is another factor which must be taken into account besides the viscoelastic properties: the density of the polymer. More mass absorbs more energy. This is usually accomplished in elastomers by adding heavy...
Since standard polyurethane foams do not melt as a thermoplast at 180°C, there are two explanations I can think of:
1)Soft PUR foams are produced using polyols and isocyanates with high molecular weights and have a relatively high degree of unlinked reactive groups in the end form. The heat...
Does anybody know of a way to modify a polyurethane elastomer formulation to make it more permeable to nitrogen or air? (permeability to CO2 or vapor is good) Could be a filler, additive or resin modifier.
Hello virteceng,
the problems with biocompatibility of PU usually come from the catalysts used (tin-organic or amines) and from the Isocyanates or manufacturing residues contained in them.
Try Air Products or Witco for questions relating to the catalysts and Bayer for the Isocyanates.
These...
For oil resistance at or above 180°C we've had excellent results with LSR silicone gaskets (FIPG). Try contacting the R&D guys at:
www.rampf-resins.com
Good Luck!
Roger
