Fluororubber composition

Patent metadata

Field	Value
Publication number	US-9441101-B2
Application number	US-201314097701-A
Country	US
Kind code	B2
Filing date	Dec 5, 2013
Priority date	Dec 7, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

Provided is a fluororubber composition which does not deteriorate workability during roll kneading, does not cause foaming during crosslinking and molding, and is capable of giving a crosslinked molded article which exhibits desired hardness and sealing property without using a reinforcing inorganic filler such as carbon black and silica. The fluororubber composition includes, relative to 100 parts by weight of a vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer having a glass transition temperature and a melting point, no reinforcing inorganic filler, 5 to 100 parts by weight of a PTFE filler, 0.5 to 10 parts by weight of a polyol crosslinking agent, 1 to 15 parts by weight of magnesium oxide, and 0.1 to 2 parts by weight of hydrotalcite. Preferably, 0.1 to 10 parts by weight of a quaternary onium salt crosslinking accelerator is further included.

First claim

The invention claimed is:

1. A fluororubber composition comprises, relative to 100 parts by weight of a vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer having a glass transition temperature and a melting point, 5 to 100 parts by weight of a PTFE filler, 0.5 to 10 parts by weight of a polyol crosslinking agent, 1 to 15 parts by weight of magnesium oxide, and 0.1 to 2 parts by weight of hydrotalcite, wherein said fluororubber composition does not contain any other inorganic reinforcing filler.

2. The fluororubber composition according to claim 1 , further comprising 0.1 to 10 parts by weight of a quaternary onium salt crosslinking accelerator.

3. The fluororubber composition according to claim 1 , wherein the fluorine-containing elastomer copolymer has a crystal fusion enthalpy ΔH of 1.0 J/g or more.

4. The fluororubber composition according to claim 1 , wherein the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by charging 20 to 40 wt % of entire charged monomers before starting a polymerization reaction; performing a copolymerization reaction with charged monomer compositions of vinylidene fluoride and hexafluoropropylene being 75 to 85 wt % and 25 to 15 wt %, respectively, before the start of the polymerization reaction; and continuing the copolymerization reaction by keeping the monomer charged compositions of vinylidene fluoride and hexafluoropropylene to be added during the polymerization reaction to 65 to 80 mol % and 35 to 20 mol %, respectively, the vinylidene fluoride and the hexafluoropropylene being in an amount of 60 to 80 wt % of the entire charged monomers.

5. The fluororubber composition according to claim 1 , the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by performing copolymerization reaction by charging an entire amount of hexafluoropropylene and 25 wt % or less of an entire charged amount of vinylidene fluoride before starting a polymerization reaction; and continuing the copolymerization reaction by adding 75 wt % or more of the entire charged amount of vinylidene fluoride.

6. The fluororubber composition according to claim 5 , wherein a fluorine-containing elastomer copolymer produced by charging a monomer mixture having monomer charged compositions of vinylidene fluoride and hexafluoropropylene of 15 to 35 mol % and 85 to 65 mol %, respectively, before starting the polymerization reaction, is used.

7. A fluororubber composition comprises, relative to 100 parts by weight of a vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer having a glass transition temperature and a melting point, 35 to 100 parts by weight of a PTFE filler, 0.5 to 10 parts by weight of a polyol crosslinking agent, 1 to 15 parts by weight of magnesium oxide, and 0.1 to 2 parts by weight of hydrotalcite, wherein said fluororubber composition does not contain any other inorganic reinforcing filler.

8. The fluororubber composition according to claim 7 , further comprising 0.1 to 10 parts by weight of a quaternary onium salt crosslinking accelerator.

9. The fluororubber composition according to claim 7 , wherein the fluorine-containing elastomer copolymer has a crystal fusion enthalpy ΔH of 1.0 J/g or more.

10. The fluororubber composition according to claim 7 , wherein the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by charging 20 to 40 wt % of entire charged monomers before starting a polymerization reaction; performing a copolymerization reaction with charged monomer compositions of vinylidene fluoride and hexafluoropropylene being 75 to 85 wt % and 25 to 15 wt %, respectively, before the start of the polymerization reaction; and continuing the copolymerization reaction by keeping the monomer charged compositions of vinylidene fluoride and hexafluoropropylene to be added during the polymerization reaction to 65 to 80 mol % and 35 to 20 mol %, respectively, the vinylidene fluoride and the hexafluoropropylene being in an amount of 60 to 80 wt % of the entire charged monomers.

11. The fluororubber composition according to claim 7 , the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by performing copolymerization reaction by charging an entire amount of hexafluoropropylene and 25 wt % or less of an entire charged amount of vinylidene fluoride before starting a polymerization reaction; and continuing the copolymerization reaction by adding 75 wt % or more of the entire charged amount of vinylidene fluoride.

12. The fluororubber composition according to claim 11 , wherein a fluorine-containing elastomer copolymer produced by charging a monomer mixture having monomer charged compositions of vinylidene fluoride and hexafluoropropylene of 15 to 35 mol % and 85 to 65 mol %, respectively, before starting the polymerization reaction, is used.

13. The fluororubber composition according to claim 12 , further consisting of 0.1 to 10 parts by weight of a quaternary onium salt crosslinking accelerator.

14. The fluororubber composition according to claim 12 , wherein the fluorine-containing elastomer copolymer has a crystal fusion enthalpy ΔH of 1.0 J/g or more.

15. The fluororubber composition according to claim 12 , wherein the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by charging 20 to 40 wt % of entire charged monomers before starting a polymerization reaction; performing a copolymerization reaction with charged monomer compositions of vinylidene fluoride and hexafluoropropylene being 75 to 85 wt % and 25 to 15 wt %, respectively, before the start of the polymerization reaction; and continuing the copolymerization reaction by keeping the monomer charged compositions of vinylidene fluoride and hexafluoropropylene to be added during the polymerization reaction to 65 to 80 mol % and 35 to 20 mol %, respectively, the vinylidene fluoride and the hexafluoropropylene being in an amount of 60 to 80 wt % of the entire charged monomers.

16. The fluororubber composition according to claim 12 , the vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer is produced by performing copolymerization reaction by charging an entire amount of hexafluoropropylene and 25 wt % or less of an entire charged amount of vinylidene fluoride before starting a polymerization reaction; and continuing the copolymerization reaction by adding 75 wt % or more of the entire charged amount of vinylidene fluoride.

17. The fluororubber composition according to claim 15 , wherein a fluorine-containing elastomer copolymer produced by charging a monomer mixture having monomer charged compositions of vinylidene fluoride and hexafluoropropylene of 15 to 35 mol % and 85 to 65 mol %, respectively, before starting the polymerization reaction, is used.

18. A fluororubber composition that consists essentially of 100 parts by weight of a vinylidene fluoride-copolymerized, fluorine-containing elastomer copolymer having a glass transition temperature and a melting point, 5 to 100 parts by weight of a PTFE filler, 0.5 to 10 parts by weight of a polyol crosslinking agent, 1 to 15 parts by weight of magnesium oxide, and 0.1 to 2 parts by weight of hydrotalcite, wherein said fluororubber composition does not contain any other inorganic reinforcing filler.

Assignees

• Nok Corp

Inventors

• Yokota Atsushi

Classifications

• C08L27/16 Primary

  Homopolymers or copolymers or vinylidene fluoride · CPC title

• C08K2003/222

  Magnesia, i.e. magnesium oxide · CPC title

• C08K5/13

  Phenols; Phenolates · CPC title

• G11B25/043

  using rotating discs · CPC title

• C08K3/22

  of metals · CPC title