What is claimed is:
1 . A dispersant attached polytetrafluoroethylene particle on whose surface a dispersant having a fluorine atom is attached, wherein a content of perfluorooctanoic acid is from 0 ppb to 25 ppb with respect to the polytetrafluoroethylene particle.
2 . The dispersant attached polytetrafluoroethylene particle as claimed in claim 1 , which has an average particle diameter of from 0.2 μm to 4.5 μm.
3 . The dispersant attached polytetrafluoroethylene particle as claimed in claim 1 , wherein the dispersant having a fluorine atom is a polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group.
4 . The dispersant attached polytetrafluoroethylene particle as claimed in claim 3 , wherein the polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group is a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) or a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) and a structural unit represented by the following formula (FB):
wherein, in the formulae (FA) and (FB), each of R F1 , R F2 , R F3 and R F4 independently represents a hydrogen atom or an alkyl group; X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond; Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —C fx H 2fx-1 (OH))- or a single bond; Q F1 represents —O— or —NH—; each of fl, fm and fn independently represents an integer of 1 or more; each of fp, fq, fr and fs independently represents 0 or an integer of 1 or more; ft represents an integer of 1 to 7; and fx represents an integer of 1 or more.
5 . The dispersant attached polytetrafluoroethylene particle as claimed in claim 1 , wherein a content of the dispersant having a fluorine atom is from 0.5% by weight to 10% by weight with respect to the polytetrafluomethylene particle.
6 . The dispersant attached polytetrafluomethylene particle as claimed in claim 5 , wherein the content of the dispersant having a fluorine atom is from 1% by weight to 7% by weight with respect to the polytetrafluoroethylene particle.
7 . A composition comprising a polytetrafluoroethylene particle and a dispersant having a fluorine atom, wherein a content of perfluorooctanoic acid is from 0 ppb to 25 ppb with respect to the polytetrafluoroethylene particle.
8 . The composition as claimed in claim 7 , wherein an average particle diameter of the polytetrafluoroethylene particle is from 0.2 μm to 4.5 μm.
9 . The composition as claimed in claim 7 , which is in a liquid state or in a solid state.
10 . The composition as claimed in claim 7 , wherein the dispersant having a fluorine atom is a polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group.
11 . The composition as claimed in claim 10 , wherein the polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group is a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) or a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) and a structural unit represented by the following formula (FB):
wherein, in the formulae (FA) and (FB), each of R F1 , R F2 , R F3 and R F4 independently represents a hydrogen atom or an alkyl group; X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond; Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —C fx H 2fx-1 (OH))— or a single bond; Q F1 represents —O— or —NH—; each of fl, fm and fn independently represents an integer of 1 or more; each of fp, fq, fr and fs independently represents 0 or an integer of 1 or more; ft represents an integer of 1 to 7; and fx represents an integer of 1 or more.
12 . The composition as claimed in claim 7 , wherein a content of the dispersant having a fluorine atom is from 0.5% by weight to 10% by weight with respect to the polytetrafluoroethylene particle.
13 . The composition as claimed in claim 12 , wherein the content of the dispersant having a fluorine atom is from 1% by weight to 7% by weight with respect to the polytetrafluoroethylene particle.
14 . A layered material comprising a polytetrafluoroethylene particle and a dispersant having a fluorine atom, wherein a content of perfluorooctanoic acid is from 0 ppb to 25 ppb with respect to the polytetrafluomethylene particle.
15 . The layered material as claimed in claim 14 , wherein an average particle diameter of the polytetrafluoroethylene particle is from 0.2 μm to 4.5 μm.
16 . The layered material as claimed in claim 14 , wherein the dispersant having a fluorine atom is a polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group.
17 . The layered material as claimed in claim 16 , wherein the polymer obtained by homopolymerization or copolymerization of a polymerizable compound having a fluorinated alkyl group is a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) or a fluorinated alkyl group-containing polymer having a structural unit represented by the following formula (FA) and a structural unit represented by the following formula (FB):
wherein, in the formulae (FA) and (FB), each of R F1 , R F2 , R F3 and R F4 independently represents a hydrogen atom or an alkyl group; X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond; Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —C fx H 2fx-1 (OH))— or a single bond; Q F1 represents —O— or —NH—; each of fl, fm and fn independently represents an integer of 1 or more; each of fp, fq, fr and fs independently represents 0 or an integer of 1 or more; ft represents an integer of 1 to 7; and fx represents an integer of 1 or more.
18 . The layered material as claimed in claim 14 , wherein a content of the dispersant having a fluorine atom is from 0.5% by weight to 10% by weight with respect to the polytetrafluoroethylene particle.
19 . The layered material as claimed in claim 18 , wherein the content of the dispersant having a fluorine atom is from 1% by weight to 7% by weight with respect to the polytetrafluoroethylene particle.
20 . An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer, wherein an outermost surface layer of the electrophotographic photoreceptor is a layer comprising the layered material as claimed in claim 14 .
21 . The electrophotographic photoreceptor as claimed in claim 20 , wherein the outermost surface layer is a surface protective layer having a crosslinked structure.
22 . A process cartridge comprising the electrophotographic photoreceptor as claimed in claim 20 , wherein the process cartridge is detachably attached to an image forming apparatus.
