Home Forums Greases Can I add a Pour point Depressent to a finished grease?

  • Can I add a Pour point Depressent to a finished grease?

    Posted by Tania Juarez on 26 January 2023 at 1:18 pm

    Just a Question, Can I add a Pour point Depressent to a finished grease in order to improve performance at low temperature?

    Rafe Britton replied 4 hours, 39 minutes ago 2 Members · 3 Replies
  • 3 Replies
  • Rafe Britton

    Administrator
    30 January 2023 at 3:23 pm
    5263
    104
    1,235

    Hi @Tania.bkt ! What’s the issue that you’re facing at low temperatures? Typically it is the thickener that becomes too thick (which isn’t solved by adding a PPD). I’d be hesitant to add any additives to a grease after it has been formulated, as the manufacturing process usually requires the additive mixing in a very controlled environment.

  • Tania Juarez

    Member
    31 January 2023 at 1:05 am
    60
    764
    360

    Hi Rafe, well I have a lithium grease tha is certificated by NLGI LB, and one of the test that the grease must fulfill is ASTM D4693 Low Temperature Torque @40°C 60 second Torque, the max. specitification is 15.5 N-m. Our grease is using Group I and the restult is 16.32 N-m. I think the best option is to chenge the type of basic oil but I just wander if adding PPD could help to improve the behavior of the grease to fulfil this test at low temperature.

    • Rafe Britton

      Administrator
      2 February 2023 at 3:11 pm
      5263
      104
      1,235

      Ahh – I see what you mean now. It really depends on the cold-temperature behaviour of the base oil as to whether a PPD will make any difference. PPDs inhibit wax crystal growth – if these crystals are emerging at -40C than the PPD would potentially make a difference to the cold flow properties. However, I’m not sure about blending it in to a fully-formulated grease. PPD’s are an additive that require heat blending into lubricant formulations, so I’m not sure how you’d get the homogenized in the correct way in an already-manufactured grease.