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PROCESS FOR COMPOUNDING FILLERS INTO POLYMERS

IP.com Disclosure Number: IPCOM000026625D
Original Publication Date: 1992-Dec-31
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 161K

Publishing Venue

Xerox Disclosure Journal

Abstract

A process for compounding fillers into polymers is disclosed. In a conventional process, fillers are dispersed in liquified resin, that is binders and solvent, using cowl mixer, ball mill, sand mill, roll mill or attritor for several hours to several dozen hours. For example, with a dispersion of composite material for organic photoconducting drums, a mixture of polyester, carbon black and other fillers is ball milled for 20 to 48 hours. There are several disadvantages of the ball milling technique, for example, (i) long process time; (ii) heat generated from friction, causing the mixture to gel; (iii) extensive cleaning of the steel balls is required after ball milling; and (iv) low yield due to difficulty in recovering material that is retained on the steel balls. The present process produces a highly homogeneous mixture of material in about three to five minutes at a high loading level. Heat release is minimized and may be controlled. Cleaning of the apparatus is easy and the yield is significantly improved. In the instant process, a rotor-stator homogenizer for dispensing fillers into the liquid resin is used. Various configurations of rotor-stator mixers, such as those supplied by Brinkmann, IKA or Greerco could also be used for this purpose. The dispersing process can be carried out in both batch and continuous mode. Temperature changes during mixing may be controlled using a cooling or heating jacket installed around the mixing chamber or vessel. Examples below show dispersion of carbon black in a thermoset resin system which is designed to produce, for example, a conductive material or organo photoconducting substrates for electrophotographic applications. To be conductive the carbon black powder is preferably dispersed homogeneously in the polymer matrix, so that when subsequent polymerization and crosslinking occur, a uniform bulk conductive deposit will result. Moreover, homogeneity is required for the final product to have an excellent surface quality after curing.

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XEROX DISCLOSURE JOURNAL

PROCESS FOR COMPOUNDING Proposed Classification FILLERS INTO POLYMERS U.S. C1.430/059 Hai-Yen Tran
Int. Hock Seng Tan C1. G03g 05/06

A process for compounding fillers into polymers is disclosed. In a conventional process, fillers are dispersed in liquified resin, that is binders and solvent, using cowl mixer, ball mill, sand mill, roll mill or attritor for several hours to several dozen hours. For example, with a dispersion of composite material for organic photoconducting drums, a mixture of polyester, carbon black and other fillers is ball milled for 20 to 48 hours. There are several disadvantages of the ball milling technique, for example, (i) long process time; (ii) heat generated from friction, causing the mixture to gel; (iii) extensive cleaning of the steel balls is required after ball milling; and (iv) low yield due to difficulty in recovering material that is retained on the steel balls. The present process produces a highly homogeneous mixture of material in about three to five minutes at a high loading level. Heat release is minimized and may be controlled. Cleaning of the apparatus is easy and the yield is significantly improved. In the instant process, a rotor-stator homogenizer for dispensing fillers into the liquid resin is used. Various configurations of rotor-stator mixers, such as those supplied by Brinkmann, IKA or Greerco could also be used for this purpose. The dispersing process can be carried out in both batch and continuous mode. Temperature changes during mixing may be controlled using a cooling or heating jacket installed around the mixing chamber or vessel. Examples below show dispersion of carbon black in a thermoset resin system which is designed to produce, for example, a conductive material or organo photoconducting substrates for electrophotographic applications. To be conductive the carbon black powder is preferably dispersed homogeneously in the polymer matrix, so that when subsequent polymerization and crosslinking occur, a uniform bulk conductive deposit will result. Moreover, homogeneity is required for the final product to have an excellent surface quality after curing. The following examples illustrate that highly homogeneous mixtures can be successfully produced using the disclosed process.

                    Example 1 An organic conductive mixture was prepared by mixing 4 g acetylene carbon black (GULF Acetylene Black AB50P) and 200 g vinyl ester resin (D1222, Ashland Chemical) in a vessel equipped with a high shear rotor-stator type mixer (model PT45/6G, supplied by Brinkmann) operating at about 5000 to 6000 rpm for 2 to 3 minutes. The dispersion quality of the mixture was tested

XEROX DISCLOSURE JOURNAL Vol. 17 No 6 November/December 1992 487

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