PEROXIDE CROSSLINKABLE FLUORORUBBER COMPOSITION

Abstract

A peroxide crosslinkable fluororubber composition comprising: (A) 0.1 to 2.5 parts by weight of a sodium salt or potassium salt of a saturated or unsaturated higher fatty acid; (B) (a) 0.1 to 3.5 parts by weight of a fluoropolyether derivative having a melting point of 70 C. or less, (b) 0.1 to 3.0 parts by weight of a poly--olefin oligomer, or (c) 0.1 to 2.0 parts by weight of an alkylamine compound having 4 to 30 carbon atoms; and (C) 0.1 to 5 parts by weight of an organic peroxide,
based on 100 parts by weight of peroxide crosslinkable fluororubber. This fluororubber composition has excellent crosslinking rate, mold release properties, hardness, compression set characteristics, and the like that are required for molding processability.

Claims

1. A peroxide crosslinkable fluororubber composition comprising: (A) 0.1 to 2.0 parts by weight of a sodium salt or potassium salt of a saturated or unsaturated higher fatty acid; (B) (a) 0.1 to 2.5 parts by weight of a fluoropolyether derivative having a melting point of 70 C. or less, (b) 0.1 to 2.0 parts by weight of a poly--olefin oligomer, or (c) 0.1 to 1.0 parts by weight of an alkylamine compound having 4 to 30 carbon atoms; and (C) 0.1 to 5 parts by weight of an organic peroxide, based on 100 parts by weight of peroxide crosslinkable fluororubber having an iodine atom and/or a bromine atom in a polymer main chain and/or side chain.

2. The peroxide crosslinkable fluororubber composition according to claim 1, wherein the peroxide crosslinkable fluororubber is a copolymer elastomer in which an iodine group and/or a bromine group is introduced into a copolymer elastomer having a ternary or binary copolymer composition of 50 to 80 mol % of vinylidene fluoride, 15 to 50 mol % of hexafluoropropylene, and 30 to 0 mol % of tetrafluoroethylene.

3. The peroxide crosslinkable fluororubber composition according to claim 1, wherein the processing aids (A) and (B) are used with their total amount being at a ratio of 0.5 to 3.0 parts by weight, based on 100 parts by weight of the peroxide crosslinkable fluororubber.

4. The peroxide crosslinkable fluororubber composition according to claim 1, wherein the sodium salt or potassium salt of a saturated or unsaturated higher fatty acid is a sodium salt or potassium salt of a saturated or unsaturated higher fatty acid, having 8 to 18 carbon atoms.

5. The peroxide crosslinkable fluororubber composition according to claim 4, wherein the higher fatty acid is a higher fatty acid derived from oils and fats.

6. The peroxide crosslinkable fluororubber composition according to claim 1, wherein the poly--olefin oligomer is an oligomer of -olefin having 3 or more carbon atoms.

7. The peroxide crosslinkable fluororubber composition according to claim 1, which is used as a molding material for sealing material.

8. A sealing material obtained by crosslinking and molding the peroxide crosslinkable fluororubber composition according to claim 7.

Description

EXAMPLES

[0049] The following describes the present disclosure with reference to Examples.

Example 1

[0050]

TABLE-US-00001 Peroxide crosslinkable VdF-TFE-HFP terpolymer 100 parts by weight (Tecnoflon P757, produced by Solvay Specialty Polymers) Carbon black (N990, produced by Cancarb 25 parts by weight Limited) Triallyl isocyanurate (TAIC, produced by Nippon 2.5 parts by weight Kasei Chemical Co., Ltd.) Organic peroxide (Perhexa 25B, produced by 0.5 parts by weight NOF Corporation) Beef tallow hardened fatty acid potassium 0.7 parts by weight (Nonsoul SK-1, produced by NOF Corporation) Fluoropolyether derivative (FPA1, produced by 0.7 parts by weight Solvay Specialty Polymers, melting point: 50 to 60 C.)
The above-mentioned components other than the organic peroxide were each kneaded using a 1 L kneader or an open roll at 100 C. or less for 10 to 30 minutes. Then, the organic peroxide was added and kneaded using a 1 L kneader or an open roll at 100 C. or less for 5 to 10 minutes, thereby producing an uncrosslinked rubber sheet through the open roll.

[0051] The uncrosslinked rubber sheet was subjected to press crosslinking (primary crosslinking) at 180 C. for 6 minutes and oven crosslinking (secondary crosslinking) at 230 C. for 24 hours, and measured or evaluated for each of the following items. An O ring for fixing was crosslinked and molded in the shape of the bearing number G25 according to JIS B2401-1: 2012 corresponding to ISO 3601-1: 2008.

[0052] Crosslinking time difference: a value obtained by subtracting the t90 value of the processing aid-free compounding (Comparative Example 1) from the t90 value of each Example or each Comparative Example was calculated as the crosslinking time difference.

[0053] When the value was less than 10 seconds, it was effective to increase the crosslinking rate, which was evaluated as .

[0054] When the value was 10 seconds or more, it delayed or was less effective to increase the crosslinking rate, which was evaluated as X.

[0055] G25 O ring outer diameter thickness: the average value of N=3 was calculated.

[0056] An O ring outer diameter thickness of 3.10.03 mm was evaluated as .

[0057] An O ring outer diameter thickness outside the above range was evaluated as X.

[0058] G25 O ring mold release properties: The mold release properties of the O ring during compression press molding in a mold with 25 cavities mold in the G25 shape were evaluated.

[0059] When the O ring was integrally released with less resistance, and no cut lines occurred between the product and burrs, this case was evaluated as .

[0060] When burrs were cut during mold release, or residues were formed in the mold, this case was evaluated as X.

[0061] Hardness difference (Shore A instantaneous value): According to JIS K6253: 2012 corresponding to ISO 7619-1: 2010

[0062] The difference from the value of the processing aid-free compounding (Comparative Example 1) was calculated.

[0063] A difference of less than +3 points was evaluated as .

[0064] A difference of +3 points or more was evaluated as X.

[0065] Compression set: The O ring in the G25 shape after primary crosslinking (before secondary crosslinking) (according to JIS K2401-1: 2012 corresponding to ISO 3601-1: 2008) was cut at two points to prepare a semi-circular sample having a thickness of about 3.1 mm. The sample was sandwiched between SUS plates and put into an oven at 175 C. in a 25% compressed state. Immediately after heating for 70 hours, the sample was released from the SUS plates and allowed to stand under room temperature conditions for 30 minutes. Then, from the changes in the outer diameter thickness before and after the test, the compression set value was calculated as the difference from the processing aid-free compounding (Comparative Example 1) (according to JIS K6262: 2013 corresponding to ISO 815-1: 2008 and ISO 815-2: 2008).

[0066] A numerical value of +3 or less was evaluated as .

[0067] A numerical value of more than +3 was evaluated as X.

Example 2

[0068] In Example 1, of the compounded processing aids (fatty acid potassium-fluoropolyether derivative), the fluoropolyether derivative was changed to the same amount (0.7 parts by weight) of poly--olefin oligomer (Dyurasin 128, produced by INEOS).

Example 3

[0069] In Example 1, of the compounded processing aids (fatty acid potassium-fluoropolyether derivative), the amount of the fluoropolyether derivative was changed to 0.5 parts by weight, and 0.2 parts by weight of aliphatic monocarboxylic acid metal salt mixture (TE58A, produced by Technical Processing), 0.5 parts by weight of beef tallow hardened fatty acid sodium salt (NS-Soap, produced by Kao Corporation), and 0.2 parts by weight of fatty acid sodium salt (SS-40N, produced by Kao Corporation) were used as fatty acid metal salt-based compounds.

Example 4

[0070] In Example 1, of the compounded processing aids (fatty acid potassium-fluoropolyether derivative), 0.5 parts by weight of fatty acid sodium salt (SS-40N) was used in place of the beef tallow hardened fatty acid potassium, and 0.5 parts by weight of octadecylamine-containing mixture (HT290, produced by ScHill+Seilacher) was used in place of the fluoropolyether derivative.

Example 5

[0071] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 0.7 parts by weight of fatty acid sodium salt (SS-40N) and 0.3 parts by weight of stearylamine (Farmin 80, produced by Kao Corporation).

Comparative Example 1

[0072] In Example 1, the processing aid was not used.

Comparative Examples 2 to 16

[0073] In Example 1, only following one kind was used in an amount of 1.4 parts by weight as the processing aid.

[0074] Comparative Example 2: Aliphatic Monocarboxylic Acid Metal Salt Mixture (TE58A)

[0075] Comparative Example 3: Beef tallow hardened fatty acid sodium salt (NS-Soap)

[0076] Comparative Example 4: Beef tallow hardened fatty acid potassium (Nonsoul SK-1)

[0077] Comparative Example 5: Fatty acid calcium salt (St-Ca, produced by Showa Chemical Industry Co., Ltd.)

[0078] Comparative Example 6: Alkylbenzenesulfonic acid sodium salt (DBS-NA, produced by Takemoto Oil & Fat Co., Ltd.)

[0079] Comparative Example 7: Fatty acid sodium salt (SS-40N)

[0080] Comparative Example 8: Stearic acid (produced by Miyoshi Oil & Fat Co., Ltd.)

[0081] Comparative Example 9: Fatty acid amide (Diamid 0-200, produced by Nippon Kasei Co., Ltd.)

[0082] Comparative Example 10: Fatty acid ester (VPA #2, produced by Chemours)

[0083] Comparative Example 11: Pentaerythritol tetrastearate (Deoflow 821, produced by DOG Chemie)

[0084] Comparative Example 12: Glycerol monooleate ester (a mixture of Emaster 510P, produced by Riken Vitamin Co., Ltd. and silica)

[0085] Comparative Example 13: Fluoropolyether derivative (FPA1)

[0086] Comparative Example 14: Poly--olefin oligomer (Dyurasin 128)

[0087] Comparative Example 15: Octadecylamine-containing mixture (HT290)

[0088] Comparative Example 16: Stearylamine (Farmin 80)

Comparative Example 17

[0089] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 1.0 part by weight of fatty acid calcium salt (St-Ca) and 1.5 parts by weight of glycerol monooleate ester (Emaster 510P), respectively.

Comparative Example 18

[0090] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 1.0 part by weight of beef tallow hardened fatty acid potassium (Nonsoul SK-1) and 1.5 parts by weight of glycerol monooleate ester (Emaster 510P), respectively.

Comparative Example 19

[0091] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 0.7 parts by weight of fatty acid calcium salt (St-Ca) and 0.7 parts by weight of fluoropolyether derivative (FPA1), respectively.

Comparative Example 20

[0092] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 0.7 parts by weight of beef tallow hardened fatty acid sodium salt (NS-Soap) and 0.7 parts by weight of fatty acid ester (VPA #2), respectively.

Comparative Example 21

[0093] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 0.7 parts by weight of fatty acid sodium salt (SS-40N) and 0.7 parts by weight of fatty acid ester (VPA #2), respectively.

Comparative Example 22

[0094] In Example 1, the compounded processing aids (fatty acid potassium-fluoropolyether derivative) were changed to 0.7 parts by weight of fatty acid sodium salt (SS-40N) and 0.7 parts by weight of pentaerythritol tetrastearate (Deoflow 821), respectively.

[0095] Following Table shows the results obtained respectively in the above Examples and Comparative Examples.

TABLE-US-00002 TABLE O ring Crosslinking O ring Mold Hardness Compression time difference Thickness release difference set Example Second Evaluation (mm) Evaluation properties Points Evaluation % Evaluation Example 1 19 3.10 1 1 Example 2 18 3.10 2 2 Example 3 12 3.12 2 2 Example 4 16 3.12 2 2 Example 5 17 3.12 2 2 Comparative 120 3.20 X X (70) (19) Example 1 Comparative 13 X 3.10 4 X 2 Example 2 Comparative 15 3.15 X 3 X 1 Example 3 Comparative 25 3.14 X 3 X 4 X Example 4 Comparative 3 X 3.17 X 3 X 2 Example 5 Comparative 11 3.16 X X 1 10 X Example 6 Comparative 23 3.16 X 2 2 Example 7 Comparative 10 X 3.11 X 2 11 X Example 8 Comparative 60 X 3.08 X 4 X 16 X Example 9 Comparative 2 X 3.10 X 4 X 2 Example 10 Comparative 0 X 3.10 X 2 2 Example 11 Comparative 30 X 3.12 X 4 X 7 X Example 12 Comparative 1 X 3.12 X 0 2 Example 13 Comparative 6 X 3.09 X 3 X 1 Example 14 Comparative 10 X 3.09 X 5 X 5 X Example 15 Comparative 14 3.13 5 X 10 X Example 16 Comparative 20 X 3.12 7 X 6 X Example 17 Comparative 0 X 3.10 6 X 2 Example 18 Comparative 7 X 3.15 X 1 1 Example 19 Comparative 15 3.11 3 X 1 Example 20 Comparative 17 3.11 3 X 1 Example 21 Comparative 10 X 3.11 2 1 Example 22