Fluorinated polymer, negative photosensitive resin composition and partition walls

Abstract

To provide a fluorinated polymer which enables to reduce the amount of residual ink on partition walls and to form an ink layer having high uniformity in film thickness, and a negative photosensitive composition. A fluorinated polymer which is a copolymer made of at least two monomers each having an ethylenic double bond, and which has a side chain having a C 20 or lower alkyl group in which at least one of its hydrogen atoms is substituted by a fluorine atom (provided that the alkyl group may contain an etheric oxygen atom between carbon atoms) and a side chain having at least two ethylenic double bonds per side chain.

1 . A process for producing a fluorinated polymer having a side chain having at least two ethylenic double bonds per side chain, comprising copolymerizing at least two monomers comprising a monomer (a1) having a C 20  or lower alkyl group in which at least one of its hydrogen atoms is substituted by a fluorine atom wherein the alkyl group optionally has an etheric oxygen atom between carbon atoms) and a monomer (a2) having a reactive group, followed by reacting an obtained copolymer with a compound (z1) having a functional group linkable with the reactive group and at least two ethylenic double bonds. 
     
     
         2 . The process according to  claim 1 , wherein the monomer (a1) is a monomer represented by formula 1:
   CH 2 ═CH(R 1 )COOXR f   Formula 1   wherein R 1  is a hydrogen atom, a methyl group or a trifluoromethyl group, X is a single bond or a C 1-8  bivalent organic group containing no fluorine atoms, and R f  is a C 20  or lower alkyl group in which at least one of its hydrogen atoms is substituted by a fluorine atom.