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PLASTICIZED BIMODAL STYRENE-ACRYLATE RESIN FOR SCD AND TCD DEVELOPERS

IP.com Disclosure Number: IPCOM000026914D
Original Publication Date: 1994-Apr-30
Included in the Prior Art Database: 2004-Apr-07
Document File: 2 page(s) / 152K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed are resins for use in electrophotography with bimodal molecular weight distributions which are prepared by emulsion polymerization techniques. These resins were used to prepare toners for single component development (SCD) and two component(TCD) applications and were found to have lower minimum fusing temperature than toner resins prepared by solution polymerization when both resins have equivalent glass transition temperatures.

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XEROX DISCLOSURE JOURNAL

PLASTICIZED BIMODAL Proposed Classification STYRENE-ACRYLATE RESIN FOR U.S. C1.430/109
SCD AND TCD DEVELOPERS
Int. Bernard Grushkin C1. G03g 09/08

Disclosed are resins for use in electrophotography with bimodal molecular weight distributions which are prepared by emulsion polymerization techniques. These resins were used to prepare toners for single component development (SCD) and two component(TCD) applications and were found to have lower minimum fusing temperature than toner resins prepared by solution polymerization when both resins have equivalent glass transition temperatures.

Generally, emulsion polymerized resins are cheaper than the equivalent material prepared by solution polymerization, particularly if multiple steps are involved. Melt blending similar resins of different molecular weights to achieve bimodal distributions is possible. However, if the difference in molecular weights is very large, adequate mixing may not be achieved, that is, on a molecular scale to obtain homogeneity.

As an example, styrene/2-ethylhexyl acrylate copolymers were prepared by emulsion polymerization and then acid coagulated. GPC analysis of the resins indicated a bimodal distribution. Resins of interest for SCD toner application in the Xerox Model 1012 and 5012/5014 copiers had a T, of about 65°C.

The prepared resins were formulated into toner with the following composition:

COMPONENT ' PERCENT Resin 46.9 B1220 Magnetite 49.6 P-51 CCA (Orient) 1.0 660P Wax (Sanyo) 2.5 R972 Aerosil (DeGussa) 0.2 (surface additive)

Toners were prepared from the above composition by extrusion, micronization, then classification to 11-12 micron sized particles. Aerosil was put on the surface of the toner using an SKM 10 Small Powder Mill. Toners were tested on a Xerox Model 1012 Copier which had been modified so that the fuser temperature could be controlled externally.

XEROX DISCLOSURE JOURNAL - Vol. 19, No. 2 MarcWApril 1994 199

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PLASTICIZED BIMODAL STYRENE-ACRYLATE RESIN FOR SCD AND TCD DEVELOPERS (Cont'd)

Prints were generated with optical densities from 0.6 to 1.4 over a tem erature range of about 350 to 420°F and abrasion results normalized to


1.2

8 AD(so1id area density).

Fusing results show that the acid coagulated bimodal resins have lower minimum fix temperatures (MFT) compared to a solution polymerized resins. For a series of toners, where MFT vs. T was plotted, it was shown that generally for an equivalent T,, the MFT is fower for tho...