Daikin Industries, Ltd.

Yuu Kadowaki

Masanori Kitaichi

Daisuke Ota

Shoji Fukuoka

Mayuko Taeda

Akinori Ueda

Kazuhiro Yamamura

Michiko Doi

Shigeru Morita

Provided is a fluororubber composition capable of providing a crosslinked fluororubber article that exhibits not only heat resistance, but also excellent mechanical properties at high temperatures. The fluororubber composition includes a fluororubber (A), a carbon black (B), and an aromatic petroleum resin (E), and the fluororubber composition has a difference δG′ (G′ (1%)−G′ (100%)) of not lower than 120 kPa and not higher than 3,000 kPa, where G′ (1%) denotes a shear modulus at a dynamic strain of 1%, G′ (100%) denotes a shear modulus at a dynamic strain of 100%, and G′ (1%) and G′ (100%) are determined by a dynamic viscoelasticity test carried out on an unvulcanised rubber with a rubber process analyzer (RPA) in a condition that the measurement frequency is 1 Hz and the measurement temperature is 100° C.

Fluororubber composition

A fluororubber composition including a fluororubber having an iodine content of 10 to 90 mol % for the total mole of the polymer end groups and a carbon black (B), wherein a difference (&#x3b4;G'), represented by G&#x2032;(1%)-G&#x2032;(100%), is not lower than 120 kPa and not higher than 3,000 kPa, where G&#x2032;(1%) denotes a shear modulus at a dynamic strain of 1% under an uncrosslinked state and G&#x2032;(100%) denotes a shear modulus at a dynamic strain of 100% under an uncrosslinked state, and G&#x2032;(1%) and G&#x2032;(100%) are determined by a dynamic viscoelasticity test with a rubber process analyzer (RPA) in a condition that the measurement frequency is 1 Hz and the measurement temperature is 100&#xb0; C.

A fluororubber composition which includes a fluororubber (A) and a carbon black (B). The fluororubber (A) is a vinylidene fluoride-based fluororubber including a structural unit (VdF unit) derived from vinylidene fluoride and a structural unit derived from at least one monomer selected from the group consisting of hexafluoropropylene (HFP), 2,3,3,3-tetrafluoro propylene, and perfluoro(alkyl vinyl ether) (PAVE). The molar ratio of the VdF unit to the structural unit derived from at least one monomer selected from the group consisting of HFP, 2,3,3,3-tetrafluoro propylene, and PAVE is 50/50 to 78/22. The fluororubber composition has a difference &#x3b4;G' (G&#x2032; (1%)-G&#x2032; (100%)) of not lower than 120 kPa and not higher than 3,000 kPa, where G&#x2032; (1%) denotes a modulus of shearing elasticity at a dynamic strain of 1%, G&#x2032; (100%) denotes a modulus of shearing elasticity at a dynamic strain of 100%, and G&#x2032; (1%) and G&#x2032; (100%) are determined by a dynamic viscoelasticity test.

The invention provides a fluororubber composition able to produce a crosslinked fluororubber article that exhibits not only heat resistance, but also excellent mechanical properties at high temperatures, and a method for producing same. The fluororubber composition contains: a fluororubber (A); and carbon black (B), wherein when the aforementioned fluororubber composition is immersed for 160 hours in an extraction solvent of acetone and hexane at an acetone:hexane mass ratio of 42.29:57.71 at 40&#xb0; C. and an extraction residue that is not extracted and remains as a solid is separated from the aforementioned extraction solvent and dried and then the dry weight of the extraction residue is measured, the quantity of a solvent-insoluble polymer is not lower than 5%.

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Settsu, Japan

Yuu Kadowaki