Crosslinked fluorine-containing elastomer fine particles, preparation process of same, and composition

Abstract

There are provided novel crosslinked fluorine-containing elastomer fine particles, a process for preparing crosslinked fluorine-containing elastomer fine particles and a resin composition comprising the same. The crosslinked fluorine-containing elastomer fine particles are crosslinked fluorine-containing elastomer fine particles having a gel fraction of not less than 85% by mass or crosslinked fluorine-containing elastomer fine particles obtained by crosslinking fluorine-containing elastomer particles having at least three iodine atoms per one polymer molecule at an end thereof. The composition is one comprising those fine particles and a synthetic resin. The preparation process is a process for preparing crosslinked fluorine-containing elastomer fine particles, characterized by subjecting peroxide-crosslinkable fluorine-containing elastomer particles to peroxide-crosslinking by heating an aqueous dispersion comprising the fluorine-containing elastomer particles, a peroxide and a polyfunctional unsaturated compound.

1 . A composition which comprises crosslinked fluorine-containing elastomer fine particles (D1) having a gel fraction of not less than 85% by mass and a synthetic resin (E) and a mass ratio of the crosslinked fluorine-containing elastomer fine particles (D1)/the synthetic resin (E) is 0.1/99.9 to 25/75. 
     
     
         2 . The composition of  claim 1 , wherein a fluorine content of fluorine-containing elastomer (a1) constituting said crosslinked fluorine-containing elastomer fine particles (D1) is not less than 65% by mass. 
     
     
         3 . The composition of  claim 1 , wherein the fluorine-containing elastomer (a1) constituting said crosslinked fluorine-containing elastomer fine particles (D1) comprises a structural unit derived from at least one monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride and a perfluoro ethylenically unsaturated compound represented by the formula (1):
   CF 2 ═CF—R f   1   (1)   wherein R f   1  is —CF 3  or —OR f   2 , where R f   2  is a perfluoroalkyl group having 1 to 5 carbon atoms.   
     
     
         4 . The composition of  claim 1 , wherein an average particle size of said crosslinked fluorine-containing elastomer fine particles (D1) is from 0.3 to 0.1 μm. 
     
     
         5 . The composition of  claim 1 , wherein said synthetic resin (E) is a tetrafluoroethylene-hexafluoropropylene copolymer. 
     
     
         6 . Crosslinked fluorine-containing elastomer fine particles (D2) obtained by crosslinking particles (A2) of a fluorine-containing elastomer (a2) having at least three iodine atoms per one polymer molecule at an end thereof. 
     
     
         7 . The crosslinked fluorine-containing elastomer fine particles of  claim 6 , wherein a fluorine content of fluorine-containing elastomer (a2) constituting said crosslinked fluorine-containing elastomer fine particles (D2) is not less than 65% by mass. 
     
     
         8 . The crosslinked fluorine-containing elastomer fine particles of  claim 6 , wherein the fluorine-containing elastomer (a2) constituting said crosslinked fluorine-containing elastomer fine particles (D2) comprises a structural unit derived from at least one monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride and a perfluoro ethylenically unsaturated compound represented by the formula (1):
   CF 2 ═CF—R f   1   (1)   wherein R f   1  is —CF 3  or —OR f   2 , where R f   2  is a perfluoroalkyl group having 1 to 5 carbon atoms.   
     
     
         9 . The crosslinked fluorine-containing elastomer fine particles of  claim 6 , wherein an average particle size of said crosslinked fluorine-containing elastomer fine particles (D2) is from 0.3 to 0.1 μm. 
     
     
         10 . A composition comprising the crosslinked fluorine-containing elastomer fine particles (D2) of  claim 6  and a synthetic resin (E). 
     
     
         11 . The composition of  claim 10 , wherein said synthetic resin (E) is a tetrafluoroethylene-hexafluoropropylene copolymer. 
     
     
         12 . Crosslinked fluorine-containing elastomer fine particles (D3) obtained by crosslinking particles (A3) of a fluorine-containing elastomer (a3) comprising a structural unit derived from an ethylenically unsaturated monomer comprising at least one fluoroolefin and a structural unit derived from a monomer represented by the formula (3c):
   CY 1   2 ═CY 2 R f   1 X 1   (3c)   wherein Y 1  and Y 2  are fluorine atom, hydrogen atom or —CH 3 ; R f   1  is a linear or branched fluoroalkylene or perfluoroalkylene group which may have an ether linkage-formable oxygen atom; X 1  is iodine atom or bromine atom.   
     
     
         13 . The crosslinked fluorine-containing elastomer fine particles of  claim 12 , wherein a fluorine content of the fluorine-containing elastomer (a3) constituting said crosslinked fluorine-containing elastomer fine particles (D3) is not less than 65% by mass. 
     
     
         14 . The crosslinked fluorine-containing elastomer fine particles of  claim 12 , wherein the fluorine-containing elastomer (a3) constituting said crosslinked fluorine-containing elastomer fine particles (D3) comprises a structural unit derived from at least one monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride and a perfluoro ethylenically unsaturated compound represented by the formula (1):
   CF 2 ═CF—R f   1   (1)   wherein R f   1  is —CF 3  or —OR f   2 , where R f   2  is a perfluoroalkyl group having 1 to 5 carbon atoms.   
     
     
         15 . The crosslinked fluorine-containing elastomer fine particles of  claim 12 , wherein an average particle size of said crosslinked fluorine-containing elastomer fine particles (D3) is from 0.3 to 0.1 μm. 
     
     
         16 . A composition comprising the crosslinked fluorine-containing elastomer fine particles (D3) of  claim 12  and a synthetic resin (E). 
     
     
         17 . The composition of  claim 16 , wherein said synthetic resin (E) is a tetrafluoroethylene-hexafluoropropylene copolymer. 
     
     
         18 . A process for preparing crosslinked fluorine-containing elastomer fine particles (D4), characterized by heating an aqueous dispersion comprising peroxide-crosslinkable fluorine-containing elastomer particles (A4), a peroxide (B) and a polyfunctional unsaturated compound (C) to subject said fluorine-containing elastomer particles (A4) to peroxide-crosslinking. 
     
     
         19 . The preparation process of  claim 18 , wherein said peroxide (B) is a persulfate and/or organic peroxide. 
     
     
         20 . The preparation process of  claim 18  or  19 , wherein said polyfunctional unsaturated compound (C) is at least one compound selected from the group consisting of an oxime-nitroso compound, a di(meth)acrylate compound, a triester compound, a triallyl isocyanurate compound and a polybutadiene compound. 
     
     
         21 . The preparation process of  claim 18 , wherein an average particle size of the fluorine-containing elastomer particles (A4) in said aqueous dispersion is from 0.01 to 0.5 μm. 
     
     
         22 . The preparation process of  claim 18 , wherein a fluorine content of fluorine-containing elastomer (a4) constituting said crosslinked fluorine-containing elastomer particles (A4) is not less than 65% by mass. 
     
     
         23 . The preparation process of  claim 18 , wherein the fluorine-containing elastomer (a4) constituting said crosslinked fluorine-containing elastomer particles (A4) comprises a structural unit derived from at least one monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride and a perfluoro ethylenically unsaturated compound represented by the formula (1):
   CF 2 ═CF—R f   1   (1)   wherein R f   1  is —CF 3  or —OR f   2 , where R f   2  is a perfluoroalkyl group having 1 to 5 carbon atoms.   
     
     
         24 . The preparation process of  claim 18 , wherein the crosslinked fluorine-containing elastomer fine particles (D4) are recovered by freeze drying after the peroxide-crosslinking. 
     
     
         25 . Peroxide-crosslinked fluorine-containing elastomer fine particles (D4) obtained by the preparation process of  claim 18 . 
     
     
         26 . The crosslinked fluorine-containing elastomer fine particles of  claim 25  having an average particle size of 0.01 to 0.5 μm. 
     
     
         27 . The crosslinked fluorine-containing elastomer fine particles of  claim 25  having a fluorine content of not less than 65% by mass. 
     
     
         28 . The crosslinked fluorine-containing elastomer fine particles of  claim 25  containing components being insoluble in acetone in an amount of not less than 80% by mass.