Method for producing acid-decomposable polymer

    公开(公告)号:US11725078B2

    公开(公告)日:2023-08-15

    申请号:US16893577

    申请日:2020-06-05

    CPC classification number: C08G63/90 B01J39/05 C08G63/66 G03F7/0045 G03F7/0392

    Abstract: [Problem to be Solved]
    To Provide a method for producing an acid-decomposable polymer having a reduced metal ion content, which suppresses decomposition and deprotection of the acid-decomposable polymer.
    [Means to Solve the Problem]
    The method for producing an acid-decomposable polymer according to the present invention comprises the steps of:



    preparing a polymer solution comprising an acid-decomposable polymer;
    washing an acidic cation exchanger with an organic solvent until the water content in the organic solvent discharged from the acidic cation exchanger falls to 400 ppm or less; and
    passing the polymer solution through the washed acidic cation exchanger to reduce the metal ion content of the polymer.

    METHOD FOR PRODUCING LITHIUM HYDROXIDE

    公开(公告)号:US20230079295A1

    公开(公告)日:2023-03-16

    申请号:US17797397

    申请日:2021-01-08

    Abstract: A method for producing lithium hydroxide that allows reducing a load of removing divalent or more ions with an ion-exchange resin is provided. The method for producing lithium hydroxide includes steps (1) to (3) below. (1) a neutralization step: a step of adding an alkali to a first lithium chloride containing liquid to obtain a post-neutralization liquid, (2) an ion-exchange step: a step of bringing the post-neutralization liquid into contact with an ion-exchange resin to obtain a second lithium chloride containing liquid, and (3) a conversion step: a step of electrodialyzing the second lithium chloride containing liquid to obtain a lithium hydroxide containing liquid. Since this producing method allows roughly removing divalent or more ions in the neutralization step, a load of metal removal with the ion-exchange resin is reducible.

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