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  1. Metten

    EPDM / Silicone discoloration problem

    Contact discoloration is a possible issue for rubber. The plasticizer in EPDM can cause it. Unless you can alter the formulation by using less and/or other types of oil, I have no solution for you.
  2. Metten

    Compounding for injection molding

    Compounds for compression aren't necessarily good for injection too. Viscosity should be low enough to ensure short injection times without scorching the rubber. Ts2 value should be high enough to have a safe window to inject the rubber and completely fill the mould. I would propose to check...
  3. Metten

    Identify gasket material

    You could measure the density to rule out a few options. I still think the supplier should be able to answer your question. They should know what they sell, certainly for a medical device. I regularly get questions about the temperature range our products can be used at, which cleaning solvents...
  4. Metten

    Identify gasket material

    Ask the supplier? You could ask for a safety data sheet.
  5. Metten

    Platinum Cure

    We use small amounts of platinum cured silicones, but do not see the same phenomenon. Store it cool and away from contamination (sulphur and other vapours).
  6. Metten

    Material alternative for Rubber Wheel chocks. (no odor)

    We use an NR/SBR blend. NBR wouldn't be my first choice, but odour isn't the reason for that.
  7. Metten

    Black Polyurethane Rubber Alternative

    The colour of the rubber has little influence on the chemical resistance. I would advice against (black) (poly)urethane rubber if you use aceton (+ other solvents).
  8. Metten

    Peroxide cure

    Post cure in oven with air circulation to reduce the amount of volatiles.
  9. Metten

    EPDM vs SBR Rubber

    EPDM peroxide: often distinct smell (not burnt!), soft dry ashes EPDM sulphur: smoke has a certain smell, soft dry ashes SBR: no special mention of the smell after burning, hard dry ashes NBR: hard and dry ashes, asphyxiating smell CR: hard and dry ashes, HCl smell (when burning with flame...
  10. Metten

    EPDM vs SBR Rubber

    Just cut a very small strip: few centimeters long, few millimeters thick. Burn that for 1-2 seconds and extinguish. You should have enough ashes to drop on a paper without the paper catching fire. By the time someone alerts your safety personel, you can get rid of the paper and open a window...
  11. Metten

    EPDM vs SBR Rubber

    Burn a small sample. If the try to smear the ashes and they are very smooth, it probably is EPDM. If the ashes are dry and hard you might have SBR (or other types of rubber). Properly formulated EPDM with peroxide cure should be able to withstand 130°C. If there is contact with glass, you...
  12. Metten

    NR Compounds for Latex Tubing

    Give the rubber molder a specification to which the rubber needs to comply and request a small vulcanised sample of the type they offer (test slab, not your required shape). example spec: NR or Latex based (the exact name really doesn't matter, if it works, it works) 30-40ShA density <1 or >1...
  13. Metten

    Dump temperature

    Have you tried two stage mixing? First stage up to 150°C fe and second stage with accelerators up to 100°C one day later?
  14. Metten

    Dump temperature

    1. A higher temperature will melt more ingredients, making the dispersion much easier. Too high temperatures will break down your elastomers or cause side reactions. The type of rubber (and formulation) will determine your dump temperatures. CR rubbers have low dump temperatures, very soft EPDM...
  15. Metten

    Positive Material Identification

    FKM normally has a higher density: 1.7 to 2.2 kg/L; NBR (Buna N) varies between 1 and 1.4 kg/L. So the weight per sheet should tell you the type.
  16. Metten

    What rubber sheet properties describe what I want to do?

    "self healing" rubber, but I do not know if there is a certain parameter for this property.
  17. Metten

    Does this compliant material exist?

    The production run is ok. You better contact a few producers to get a price idea for your mold and per article.
  18. Metten

    Does this compliant material exist?

    1. possible 2. quite low, but possible 3. shape is not an issue for elastic materials Economically possible: depends on the quantity of spheres. Does the type of rubber matter?
  19. Metten

    EPDM gasket stretching

    10 minutes postcure does not make sense to me. 2-3 hours at 120 to 150°C sounds normal (up to 24 hours even). Steam pressure is directly linked to the temperature. If they are 100% certain of the temperature, they know the pressure. I they are not sure about the pressure, that would mean they...
  20. Metten

    EPDM gasket stretching

    Only the supplier can give information of the normal curing of the used formulation and should be able to give info on the results of the lot in question. Might be interesting to know if the gaskets are post cured or not.

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