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Thread: Stearic Acid Residue from ABS Resin

  1. #1

    Stearic Acid Residue from ABS Resin

    We currently run a new tool with Lustran 451 resin. We are seeing droplets of a liquid build up in the vents very quickly. We had the residue tested and found it to be stearic acid, a component of the ABS resin. We opened all the vents and made the prob elm worse. Tried many different process/machine changes without success. Has anyone seen this and have any suggestions on cause?

  2. #2
    Join Date
    Aug 2011
    Location
    Upstate of South Carolina
    Posts
    664

    Re: Stearic Acid Residue from ABS Resin

    Where are the barrel heats and what is the shot utilization or resident time?
    Rick

  3. #3

    Re: Stearic Acid Residue from ABS Resin

    Quote Originally Posted by rickbatey View Post
    Where are the barrel heats and what is the shot utilization or resident time?
    Rick
    They are from 455 to 465 degrees with a melt temp of 482. We are using about 40% of the barrel and a residence time of 3 to 4 minutes. We have tried different temps up and down without success.

  4. #4
    Join Date
    Jun 2014
    Location
    EU
    Posts
    99

    Re: Stearic Acid Residue from ABS Resin

    Does it happend also with another ABS material grade?
    Did you tested a new batch of the Lustran 451?

    on the other hand, check also your chemicals - lubricants.
    It can be that this "droplets" are just coming there with the operators use some chemistry too much.

    Disasembly and clean the tool completly. Than asembly and put on the machine. Lower to minimum the lubricants and separators used.

    than let us know
    J.

  5. #5
    Join Date
    Dec 2016
    Posts
    131

    Re: Stearic Acid Residue from ABS Resin

    Hello Jeff,

    I believe I have seen exactly your problem, as I also posted here:

    http://www.injectionmoldingonline.co...sidue+vents%2C

    or search for "oily droplet residue in vents abs"

    Never Resolved! , Try a different ABS, let us know if you find one that works, we could not.

    Good Luck!
    Joel

  6. #6
    Join Date
    Jan 2020
    Posts
    14

    Re: Stearic Acid Residue from ABS Resin

    From my experience with abs it has been a heat issue where this appears or more precisely a degradation issue. When it would sit to long in a manifold/barrel or when heated too much or surprisingly when it was not dried properly

  7. #7
    Join Date
    Nov 2012
    Posts
    121

    Re: Stearic Acid Residue from ABS Resin

    stearic acid is used as a chemical component for butadiene rubber in ABS. If is a "too much" stearic acid used, it worked also as a lubricalion for improving MFI. The stearic acid can be found also on survace of product. To avoid this issue helps: lower melt temp, lower shear in materiál....

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