Continuous contained-media micromedia milling process

Patent metadata

Field	Value
Publication number	US-2016016176-A1
Application number	US-201514826772-A
Country	US
Kind code	A1
Filing date	Aug 14, 2015
Priority date	Feb 28, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

An apparatus and continuous process for making milled solid in liquid dispersions comprises several steps: 1) Forming a pre-mill mixture of pre-mix, milling media, and previously milled dispersion. 2) Milling the pre-mill mixture to form a milled mixture of milling media and milled dispersion. 3) Separating a portion of the milled dispersion, which is substantially free of milling media, from the milled mixture. 4) Recycling the un-separated mixture by adding additional pre-mix to form the pre-mill mixture to create a continuous milling process. The pre-mix comprises a liquid and a solid. The process is a continuous process and the milling media is recycled through the milling step. Much of the milled dispersion is also cycled through the milling step several times and only a portion of the milled dispersion, which is substantially free of milling media, is removed as the milled dispersion product.

First claim

1 . A continuous process for making a milled solid in liquid dispersion comprising the steps of:
forming a pre-mill mixture of pre-mix, milling media, and previously milled dispersion; milling the pre-mill mixture to form a milled mixture of milling media and milled dispersion in a mill; separating a portion of the milled dispersion comprising the milled solid, which is substantially free of milling media, from the milled mixture; and recycling the un-separated mixture by adding additional pre-mix to form pre-mill mixture to create a continuous milling process; wherein the pre-mix comprises liquid and a solid.

2 . The process of claim 1 , wherein the separation percentage is about 0.01% to about 45%.

3 . The process of claim 1 , wherein the milling step is performed in one or more mills, wherein each mill is selected from a rotor stator, an in-line disperser, a vertical media mill, a horizontal media mill, a tank and disperser, a tank and an overhead rotor stator, an impingement mill, an ultrasound mill, and a vibratory mill.

4 . The process of claim 1 , wherein the separating step is performed by one or more separators, wherein each separator is selected from a drum filter, a screw press, a pressure screen filter, a non-pressure screen filter, a sieve, fiber filter, and a micron pored-filter or porous filter.

5 . The process of claim 4 , wherein the screw press comprises a separating screen with a median pore size from about 500 microns to about 1 microns constructed with either discrete pores or porous metal or plastic.

6 . The process of claim 4 , wherein the pressure screen filter or non-pressure filter comprises a separating screen with a median pore size from about 500 to about 1 micron.

7 . The process of claim 1 , wherein the recycling step is performed in a feed vessel; wherein the feed vessel feeds the pre-mill mixture into at least one mill.

8 . The process of claim 1 , wherein the recycling step is performed in the mill.

9 . The process of claim 1 , wherein the recycling step is a direct injection of the un-separated dispersion into the flow of the pre-mill mixture before it enters the mill.

10 . The process of claim 1 , wherein the milling media is polymeric, resinous, inorganic, or has a density difference between the milling media and dispersion of less than about 0.5 g/ml.

11 . The process of claim 1 , wherein the median particle size of the milling media is less than about 500 microns.

12 . The process of claim 1 , wherein the dispersion components comprise a solid selected from organic pigments, inorganic pigments, amorphous dyes, crystalline dyes, and combinations thereof, wherein the dispersion components comprise a liquid medium selected from water, ethanol, butanol, propanol, n-propanol, glycol monoethers, acetates, ketones, toluene, hydrocarbons, and mixtures thereof.

13 . The process of claim 1 , wherein the milled solid of the milled solid dispersion in a liquid medium is a pigment.

14 . The process of claim 1 , wherein the amount of dispersion components added to the un-separated mixture is about equal to the amount of milled dispersion that is removed from the milled mixture.

15 . An apparatus comprising a separator and a mill;
wherein the mill is structured to grind a pre-mill mixture comprising a milling media and solid or semi-solid particles in a liquid medium to form a milled mixture of milled dispersion with milling media; wherein the apparatus is structured to allow the milled mixture to be fed into the separator; wherein the separator is structured to separate a portion of the milled dispersion, which is substantially free of milling media, from the milled mixture; and wherein the resulting un-separated mixture is fed directly or indirectly back into the mill.

16 . The apparatus of claim 15 , additionally comprising a feed vessel which is structured to receive the un-separated mixture from the separator; the un-separated mixture is mixed with additional solid or semi-solid particles in a liquid medium to form a pre-mill mixture in the feed vessel; and the pre-mill mixture is fed into the mill.

17 . The apparatus of claim 15 , wherein there is one or more mill, and each mill is selected from a rotor stator, an in-line disperser, a vertical media mill, a horizontal media mill, a tank and disperser, a tank and an overhead rotor stator, an impingement mill, an ultrasound mill, and a vibratory mill.

18 . The apparatus of claim 15 , wherein there is one or more separator, and each separator is selected from a drum filter, a screw press, a pressure screen filter, a non-pressure screen filter, fiber, a micron pored-filter or porous filter, and a centripetal separator.

19 . The apparatus of claim 18 , wherein the separator is a screw press which comprises a separating screen with a median pore size from about 1 to about 500 microns constructed from either discrete pores or porous metal or plastic.

20 . The apparatus of claim 18 , wherein the separator is a pressure screen filter and is operated continuously, wherein the screen has a median pore size between 1 and 500 microns.

Assignees

• Sun Chemical Corp

Inventors

• Melick Michael Ray
• Henderson Donald C

Classifications

• B02C17/16

  Mills in which a fixed container houses stirring means tumbling the charge · CPC title

• B02C23/12

  with return of oversize material to crushing or disintegrating zone · CPC title

• B02C17/20

  Disintegrating members · CPC title

• B02C17/161 Primary

  Arrangements for separating milling media and ground material · CPC title