High resistivity coating compositions having unique percolation behavior, and electrostatic image developing systems and components thereof incorporating same

Patent metadata

Field	Value
Publication number	US-9546286-B2
Application number	US-201214233457-A
Country	US
Kind code	B2
Filing date	Jul 20, 2012
Priority date	Jul 22, 2011
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

Disclosed herein are resistive composites comprising at least one resin; at least one carbon black having a surface hydrophobically modified with at least one organic group, the at least one organic group having a molecular weight of the composite of 4000 or less and comprising the formula —X(G)-, wherein X is directly attached to the at least one carbon black and is selected from arylene, heteroarylene, and alkylene, G is a substituent of X, and —X(G)- is nonionic; and wherein the resistive composite has a volume resistivity, R v , at a relative volume fraction, X CB , of the at least one carbon black in the coating, where R v is at least 10 6 ohm-cm; and log R v has a substantially linear relationship with X CB when X CB is varied from 0.1 to 0.5. Also disclosed are coatings made from such composites, such as coatings for rollers/belts for office automation machines, and methods of making such coatings.

First claim

The invention claimed is:

1. A resistive composite comprising:
at least one resin;
at least one carbon black having a surface hydrophobically modified with at least one organic group, the at least one organic group having a molecular weight of 4000 or less and comprising the formula —X(G)-, wherein X is directly attached to the at least one carbon black and is selected from arylene, heteroarylene, and alkylene, G is a substituent of X, and —X(G)- is nonionic, and wherein:
the resistive composite has a volume resistivity, R v , at a relative volume fraction, X CB , of the at least one carbon black in the composite, where R v is at least 10 6 ohm-cm; and
log R v has a substantially linear relationship with X CB when X CB is varied from 0.1 to 0.5.

2. The resistive composite of claim 1 , wherein X CB ranges from 0.1 to 0.6.

3. The resistive composite of claim 1 , wherein R, ranges from 10 6 to 10 12 ohm-cm.

4. The resistive composite of claim 1 , wherein the substantially linear relationship has a goodness of fit value (R 2 ) of at least 0.8.

5. The resistive composite of claim 1 , wherein the substantially linear relationship is defined as log R v being directly proportional to -m.X CB , wherein m is greater than 0 and no more than 15.

6. The resistive composite of claim 1 , wherein the composite has a surface resistivity, R s , of at least 10 6 ohm/square.

7. The resistive composite of claim 1 , wherein the at least one organic group has a molecular weight of 2000 or less.

8. The resistive composite of claim 1 , wherein G comprises at least one group selected from alkyls, carboxylic acid esters, amides, alcoxyls, ethers, ketones, acyls, and halides.

9. The resistive composite of claim 1 , wherein —X(G)- is a monomer and the at least one organic group comprises an oligomer.

10. The resistive composite of claim 9 , wherein the at least one organic group comprises the formula —[X(G)]- and n ranges from 1 to 20.

11. The resistive composite of claim 1 , wherein the at least one carbon black is further modified with adsorbed oligomers derived from the —X(G)- monomers.

12. A substrate coated with the resistive composite of claim 1 .

13. The substrate of claim 12 , wherein the substrate is selected from a charge roller of an electrostatic image forming apparatus, a transfer roller or belt of an electrostatic image forming apparatus, and a developer-carrying roller for carrying a developer layer thereon positioned in a toner cartridge.

14. An electrostatic image forming apparatus comprising:
an electrostatic image-bearing member; and
at least one of:
a charge roller;
a transfer roller or belt; and
a developer-carrying roller for carrying a developer layer thereon positioned in a toner cartridge,

wherein the at least one of the charge roller, the transfer roll or belt, and the developer-carrying roller has an outer layer comprising the resistive composite of claim 1 .

15. A method of making a coated substrate, comprising:
applying a composition onto a substrate, the composition comprising:
at least one resin;
at least one carbon black having a surface hydrophobically modified with at least one organic group, the at least one organic group having a molecular weight of 4000 or less and comprising the formula —X(G)-, wherein X is directly attached to the at least one carbon black and is selected from arylene, heteroarylene, and alkylene, G is a substituent of X, and —X(G)- is nonionic; and
sufficient vehicle to disperse the carbon black, and

curing the composition to form the coated substrate
wherein:
the resistive composite has a surface resistivity, R s , at a relative volume fraction, X CB , of the at least one carbon black in the coating, where R s is at least 10 6 ohm/square; and
log R s has a substantially linear relationship with X CB when X CB is varied from 0.1 to 0.5.

16. The method of claim 15 , wherein the at least one resin is curable and is selected from acrylics, urethanes, epoxies, polyimides, polyesters, and blends and copolymers thereof.

17. A resistive composite comprising: at least one resin; at least one carbon black having a surface hydrophobically modified with at least one organic group, the at least one organic group having a molecular weight of 4000 or less and comprising the formula —[X(G)] n -, where X is directly attached to the at least one carbon black and is selected from arylene, heteroarylene, and alkylene, G is a substituent of X, and —X(g)- is nonionic, and n ranges from 1 to 20, and wherein: the resistive composite has a volume resistivity, R v , at a relative volume fraction, X CB , of the at least one carbon black in the composite, where R v is at least 10 6 ohm-cm, and log R v has a substantially linear relationship with X CB when X CB is varied from 0.1 to 0.5.

18. The resistive composite of claim 17 , wherein the composite has a surface resistivity, R, of at least 10 6 ohm/square.

19. The resistive composite of claim 17 , wherein G comprises at least one group selected from alkyls, carboxylic acid esters, amides, alcoxyls, ethers, ketones, acyls, and halides.

Assignees

• Step Eugene N
• Korchev Andriy
• Kyrlidis Agathagelos
• Haynes Clovis D
• Schulz Gregory R
• Szwec John R
• Cabot Corp

Inventors

• Step Eugene N
• Korchev Andriy
• Kyrlidis Agathagelos
• Haynes Clovis D
• Schulz Gregory R
• Szwec John R

Classifications

• G03G15/0233

  Structure, details of the charging member, e.g. chemical composition, surface properties · CPC title

• C09C3/08

  Treatment with low-molecular-weight {non-polymer} organic compounds {(C09C3/006, C09C3/048 take precedence)} · CPC title

• C09C1/48

  Carbon black · CPC title

• G03G15/0815

  characterised by the developer handling means after the developing zone and before the supply, e.g. developer recovering roller · CPC title

• C01P2006/40

  Electric properties · CPC title