FLUORORUBBER COMPOSITION CONTAINING EPOXIDIZED POLYBUTADIENE

Abstract

A fluororubber composition contains 0.1 to 50 parts by weight of an epoxidized polybutadiene with respect to 100 parts by weight of a fluororubber. As the fluororubber, a vinylidene fluoride-hexafluoropropylene copolymer (FKM), a tetrafluoroethylene-propylene-based copolymer (FEPM), a tetrafluoroethylene-perfluoroalkyl vinyl ether-based copolymer (FFKM), or the like is exemplified. The fluororubber composition may further contain a vulcanizing agent or the like.

Claims

1. A fluororubber composition, comprising 0.1 to 50 parts by weight of an epoxidized polybutadiene with respect to 100 parts by weight of a fluororubber.

2. The fluororubber composition according to claim 1, wherein the fluororubber is at least one copolymer selected from a vinylidene fluoride-hexafluoropropylene copolymer (FKM), a tetrafluoroethylene-propylene-based copolymer (FEPM), and a tetrafluoroethylene-perfluoroalkyl vinyl ether-based copolymer (FFKM).

3. The fluororubber composition according to claim 1, further comprising a vulcanizing agent.

4. The fluororubber composition according to claim 1, wherein the epoxidized polybutadiene is an epoxidized polybutadiene consisting of repeating units of formula (I), formula (II), formula (III), and formula (IV). ##STR00003##

5. The fluororubber composition according to claim 4, wherein a total proportion of the repeating units of formula (I) and formula (II) in all the repeating units of the epoxidized polybutadiene is 75 to 99 mol %.

6. The fluororubber composition according to claim 4, wherein a total proportion of the repeating units of formula (I) and formula (III) in all repeating units of the epoxidized polybutadiene is 1 to 90 mol %.

7. The fluororubber composition according to claim 6, wherein the total proportion of the repeating units of formula (I) and formula (III) in all repeating units of the epoxidized polybutadiene is 1 to 40 mol %.

8. The fluororubber composition according to claim 1, wherein a number-average molecular weight (Mn) of the epoxidized polybutadiene is 500 to 10,000.

9. A molded product made by molding the fluororubber composition according to claim 1.

Description

EXAMPLES

[0037] Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to the scope of the examples.

[0038] Substances used in the examples and comparative examples are shown in Table 1.

TABLE-US-00001 TABLE 1 Product name Producer Acid Epoxidized- NISSO-PB Nippon Soda acceptor polybutadiene JP-100 Co., Ltd. A Epoxidized — — polybutadiene B*.sup.1 Magnesium KYOWAMAG Kyowa Chemical oxide (registered Industry Co., Ltd. trademark) #150 Lead Lead (II) Hiroshima Wako monoxide oxide reagent Co., Ltd. special grade Fluororubber FKM G-701 DAIKIN Industries, Ltd. Vulcanization Calcium CALDIC#1000 Ohmi Chemical accelerator hydroxide Industry Co., Ltd. Reinforcing Carbon black THERMAX Cancarb Inc. agent N990 *.sup.1Epoxidized polybutadiene produced in Production Example 1

Production Example 1

[0039] With reference to “Synthesis of Polymers (I)” edited by Takeshi Endo, 1st edition, Kodansha Ltd., 2010, 1,4-polybutadiene (1,4-PB) was synthesized using an alkali metal as an initiator. Mn was approximately 2000, and the 1,2-vinyl rate was approximately 20%. The obtained 1,4-PB was epoxidized using the method described in Japanese unexamined Patent Application Publication No. 51-36448, and epoxidized 1,4-PB having an epoxy equivalent of approximately 230 was obtained.

Example 1

[0040] FKM (100 parts by weight), an epoxidized polybutadiene A (3 parts by weight), calcium hydroxide (6 parts by weight), and carbon black (20 parts by weight) were kneaded with a mill, thereby obtaining a fluororubber composition. The obtained fluororubber composition was press-vulcanized at 170° C. for 12 minutes and further heated in an oven at 230° C. for 24 hours for secondary vulcanization, thereby obtaining a vulcanizate. The obtained vulcanizate was subjected to a tensile test, a tearing test, a water resistance test, a chlorine resistance test, and an acid resistance test. The results of these tests are shown in Table 2.

Example 2

[0041] A vulcanizate was obtained in the same manner as in Example 1 except that an epoxidized polybutadiene B (3 parts by weight) was used instead of the epoxidized polybutadiene A. The obtained vulcanizate was subjected to a tensile test, a tearing test, a water resistance test, a chlorine resistance test, and an acid resistance test. The results of these tests are shown in Table 2.

Comparative Example 1

[0042] A vulcanizate was obtained in the same manner as in Example 1 except that magnesium oxide (3 parts by weight) was used instead of the epoxidized polybutadiene A and the resulting fluororubber composition was press-vulcanized at 170° C. for 15 minutes. The obtained vulcanizate was subjected to a tensile test, a tearing test, a water resistance test, a chlorine resistance test, and an acid resistance test. The results of these tests are shown in Table 3.

Comparative Example 2

[0043] A vulcanizate was obtained in the same manner as in Example 1 except that lead monoxide (5 parts by weight) was used instead of the epoxidized polybutadiene A and the resulting fluororubber composition was press-vulcanized at 170° C. for 15 minutes. The obtained vulcanizate was subjected to a tensile test, a tearing test, a water resistance test, a chlorine resistance test, and an acid resistance test. The results of these tests are shown in Table 3.

Testing Methods

“Tensile Test”

[0044] The tensile strength and the elongation at breaking were measured based on JIS K 6251: 2010 “Rubber, vulcanized or thermoplastics-Determination of tensile stress-strain properties”.

“Tearing Test”

[0045] The tearing strength was measured based on JIS K 6252: 2007 “Rubber, vulcanized or thermoplastic-Determination of tear strength”.

“Water Resistance and Acid Resistance Tests”

[0046] The volume changes after immersing the vulcanizate in water, 600 ppm chlorinated water, 10% nitric acid, and 20% hydrochloric acid at 80° C. for 168 hours were measured based on JIS K 6258: 2010 “Rubber, vulcanized or thermoplastic-Determination of the effect of liquids”.

TABLE-US-00002 TABLE 2 Example 1 Example 2 Epoxidized polybutadiene A 3 Epoxidized polybutadiene B 3 FKM 100 100 Carbon black 20 20 Calcium hydroxide 6 6 Tensile test Tensile MPa 15.6 13.3 strength Elongation % 210 180 at breaking M100 MPa 7.46 7.13 M200 MPa 15.3 — Tearing test Tearing N/ 24.3 24.7 strength mm Pure water immersion Volume % 3 3 test (80° C. × 168 h) change 600 ppm Chlorinated Volume % 5 4 water immersion test change 10% Nitric acid Volume % 11 11 immersion test change 20% hydrochloric Volume % 11 10 acid immersion test change

TABLE-US-00003 TABLE 3 Comparative Comparative Example 1 Example 2 Magnesium oxide 3 Lead monoxide 5 FKM 100 100 Carbon black 20 20 Calcium hydroxide 6 6 Tensile test Tensile MPa 15.6 13.7 strength Elongation % 210 230 at breaking M100 MPa 5.45 5.62 M200 MPa 14.5 12.2 Tearing test Tearing N/mm 25.2 23.9 strength Pure water immersion Volume % 2 1 test (80° C. × 168 h) change 600 ppm Chlorinated Volume % 12 8 water immersion test change 10% Nitric acid Volume % 55 16 immersion test change 20% hydrochloric Volume % 24 8 acid immersion test change