JPH0625498A - Fluororubber composition - Google Patents

Abstract

PURPOSE:To obtain a fluororubber compsn. which is excellent in roll processing properties and extrusion characteristics and gives a vulcanized molding having high mechanical strengths and elongation and a good compatibility by compounding an unvulcanized fluororubber with a specific fluorinated organosilicon compd. and a vulcanizing agent. CONSTITUTION:A fluororubber compsn. is prepd. by compounding an unvulcanized fluororubber with a fluorinated organosilicon compd. of formula I {wherein R<1> is a monovalent hydrocarbon group; R<2> is a divalent hydrocarbon group; Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group; Q is a divalent siloxy group of formula II, III, or IV [wherein R<5>, R<6>, and R' are each an optionally substd. monovalent hydrocarbon group]; and (n) is an integer of 0 or higher} and a vulcanizing agent. The addition of the fluorinated organosilicon compd. to the unvulcanized fluororubber greatly improves the roll processing properties and extrusion characteristics and gives a vulcanized molding free from bleeding and having a good compatibility without detriment to the mechanical strengths and elongation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororubber composition which is excellent in roll processability and extrusion properties, has good mechanical strength and elongation, and gives a vulcanized molded product having good compatibility.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Fluorine rubber is used in various fields because it is excellent in chemical resistance, solvent resistance, heat resistance and the like.

However, fluorine raw rubber is very high in viscosity and hard, it is difficult to uniformly knead the filler into the raw fluorine rubber during roll processing, and the mixing operation such as turning back on the roll is not easy. In addition to being inferior in properties, there is a problem that a high power is required during the extrusion process and the heat generation is large. For this reason, it has been desired to improve roll processability and extrusion properties of fluororubber compositions.

To improve the workability of this fluororubber composition, JP-A-62-277456 proposes a method of adding a low-viscosity fluororubber having the following structure as a reactive plasticizer.

[0005]

[Chemical 2]

However, the above-mentioned method using the fluororubber internal additive has a problem that bleeding is observed on the rubber surface after curing and that the mechanical strength and elongation of the vulcanized molded product are easily impaired.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a fluororubber composition which is excellent in roll processability and extrusion properties, has good mechanical strength and elongation, and gives a vulcanized molded product having good compatibility with no bleeding. .

[0008]

Means and Actions for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has found that the fluorine-containing organosilicon represented by the following general formula (I) is used for unvulcanized fluororubber. By adding a compound, roll processability,
It was found that the extrusion characteristics are remarkably improved, and that the vulcanized molded product obtained by vulcanizing this has good compatibility without impairing mechanical strength and elongation, and without causing bleeding. Thus, the present invention has been completed.

[0009]

[Chemical 3]

Therefore, the present invention provides (1) an unvulcanized fluororubber, (2) a fluorine-containing organosilicon compound of the above formula (I),
And (3) A fluororubber composition containing a vulcanizing agent.

The present invention will be described in more detail below. As the first component of the fluororubber composition of the present invention, various fluororubbers can be used. For example, a vinylidene fluoride-based copolymer can be used. , For example, a copolymer of at least one selected from vinylidene fluoride and tetrafluoroethylene and propylene hexafluoride, at least one selected from vinylidene fluoride, ethylene tetrafluoride, pentaprotonated propylene and propylene hexafluoride And a copolymer of these and a monomer copolymerizable with these (for example, olefins having an ether bond in the side chain such as trifluoroethylene trifluoromethyl ether, olefins such as ethylene, propylene, and isobutylene, trifluoroethylene, Halogenated olefins such as monochlorotrifluoroethylene, perfluorobutyl ethyl Emissions _{(C 4 F 9 CH = CH} 2), perfluoro hexaethylene _{(C 6 F 13 CH = CH} 2), perfluorooctyl ethylene _{(C 8 F 17 CH = CH} 2) olefins having a fluorinated alkyl group such as And halogenated ethers such as perfluoroperfluorovinyl ether and alkyl-fluorovinyl ether, and ethers such as ethyl vinyl ether), and these can be used alone or in combination of two or more.

Specifically as such a fluororubber,
Commercially available products such as DuPont's VITON series, 3M's Florel series, Daikin Industries 'Daiel series, JSR / Asahi Glass' Afras series, Asahi Montmon's Technoflon series, etc. can be used.

The second component of the present invention is a fluorine-containing organosilicon compound represented by the following general formula (I).

[0014]

[Chemical 4]

In the above formula, R ¹ represents a monovalent hydrocarbon group, preferably having 1 to 8 carbon atoms, and specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group and isobutyl group. Group, cycloalkyl group such as cycloalkyl group, alkenyl group such as vinyl group and allyl group, aryl group such as phenyl group and tolyl group, or 3,3,3
Examples thereof include a group in which a hydrogen atom of the above group such as a trifluoroethyl group and a 3-chloropropyl group is partially substituted with a halogen atom. R ² represents a divalent hydrocarbon group, preferably having 1 to 8 carbon atoms, and specific examples thereof include alkylene groups such as methylene group, ethylene group and propylene group, arylene groups such as benzylene group and tolylene group. Are exemplified.

In the above formula (I), Rf is a divalent perfluoroalkylene group (preferably having 1 to 15 carbon atoms).
Alternatively, it is a divalent perfluoropolyether group (preferably having a carbon number of 2 to 100), and specific examples include those having the following formulas.

[0017]

[Chemical 5]

Further, Q is the following general formula (II), (III)
Alternatively, it is a divalent siloxy group represented by (IV).

[0019]

[Chemical 6]

Where R³ , R^Four, R^Five, R⁶As above
R¹And the same groups as. As such a Q
Specifically, the following formulas are exemplified. In the formula
Ph represents a phenyl group.

[0021]

[Chemical 7]

The above-mentioned fluorine-containing organosilicon compounds may be used alone or in combination of two or more, and the addition amount thereof is 100 parts by weight of the first component fluororubber (weight part, the same applies hereinafter).
However, it is preferably 0.01 to 50 parts, and more preferably 2 to 30 parts. Addition amount of fluorine-containing organosilicon compound is 0.0
If it is less than 1 part, there is little effect on roll processability and extrudability, and if it exceeds 50 parts, the rubber physical properties of the fluororubber may deteriorate.

The vulcanizing agent of the third component of the present invention is appropriately selected according to the type of fluororubber, and known ones can be used.
For example, an amine compound, a fluorine-containing polyol compound, a peroxide compound or the like can be used.

The addition amount of the vulcanizing agent is not particularly limited, but 0.01 to 5 parts, particularly 0.1 to 100 parts of fluororubber.
It is preferable to be 1 part.

The fluororubber composition of the present invention may optionally contain various additives such as fillers such as carbon black, silica, clay, diatomaceous earth and talc, and other various additives usually added to fluororubbers. Although a predetermined amount can be added, it is particularly preferable to add an acid acceptor that is commonly used for vulcanization. Examples of the acid acceptor include metal oxides such as magnesium oxide and zinc oxide, metal hydroxides such as calcium hydroxide, epoxy compounds, organic tin compounds, and alkaline earth metal salts. The above acid acceptors may be used alone or in combination of two or more, and the addition amount thereof is preferably 1 to 30 parts with respect to 100 parts of the fluororubber.

The fluororubber composition of the present invention can be produced by an ordinary method. For example, the necessary compounding ingredients are usually used in a mixing machine such as a rubber kneading roll and a pressure kneader to prepare the composition.
The rubber composition can be produced by mixing at -100 ° C, preferably 30-60 ° C. in this case,
When the mixing temperature is lower than 30 ° C., it may be difficult to uniformly mix the organic compounds, and conversely, the mixing temperature may be too high to successfully mix even if it exceeds 100 ° C.

Further, the molding can be carried out by employing various molding methods such as extrusion molding, injection molding and calender molding. In addition, it is desirable that the fluororubber composition is first subjected to primary vulcanization molding and then subjected to secondary heat treatment, which further improves physical properties such as tensile strength, elongation and tear strength of the vulcanized molding. be able to. The primary vulcanization is usually carried out at 50 to 250 ° C for 0.1 to 1 hour, and the secondary heat treatment is usually carried out at 150 to 250 ° C for 2 to 48 hours.
It is preferable to set the time, particularly about 4 to 24 hours.

[0028]

EFFECT OF THE INVENTION The fluororubber composition of the present invention is excellent in roll processability and extrusion properties, and also has good mechanical strength.
Since it has elongation, has no bleeding, and has good compatibility, it can be widely used in various fields.

[0029]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 6 and Comparative Examples 1 to 4] The compounding components shown in Table 1 were sufficiently kneaded with a two-roll to prepare fluororubber compositions. The fluorine-containing organosilicon compound used in this fluororubber composition is as follows.

[0031]

[Chemical 8]

Next, the obtained rubber composition was treated at 170 ° C. for 1 hour.
After press vulcanization for 5 minutes, it was oven vulcanized at 230 ° C. for 24 hours to prepare a vulcanized rubber sheet.

Regarding this vulcanized rubber sheet, its hardness,
Tensile strength, elongation, tear strength, impact resilience and compression set were measured by the methods described in JIS-K-6301. In addition, the roll processability of the rubber composition (degree of contamination of the roll surface after roll processing, press workability (sheet distributability), mold release property of vulcanized product) and bleeding property of the rubber composition were evaluated by the following methods. . The results are shown in Table 1.

Roll processability The roll interval and the roll time of 20 minutes / batch were used to measure the number of times the roll turning operation can be performed during roll processing, and the mixing state of the filler at that time and the adhesion of the rubber composition to the roll surface were measured. Was observed and evaluated according to the following criteria. ◯: It is possible to cut back 40 times or more. The mixed state of the filler is good. The rubber composition was never attached to the roll. (Triangle | delta): 25 to 39 times can be turned back. In the mixed state of the filler, a layer of the filler is recognized on the surface. The rubber composition tends to adhere to the roll surface during processing, resulting in poor roll releasability. X: The turning back operation can be performed less than 25 times. In the mixed state of the filler, a layer of the filler is recognized on the surface. The rubber composition adheres to the roll surface during processing, and the roll must be stopped during the roll operation to cool the roll surface.

[0035] was allowed to stand sheet prepared in bleeding aforementioned method 1 day at room temperature, pressing the glass sheet in the sheet was observed bleed to the surface of the glass. ◯: Almost no oily substance is observed on the glass surface. X: An oily substance is observed on the glass surface.

Next, the fluidity was measured by a flow tester by the following method. The results are shown in FIGS. Measurement of fluidity using a flow tester Using a flow tester CFT-500A manufactured by Shimadzu Corporation, a flow value Q (cm ^{3) at} each temperature was applied with a pressure of 40 atm.
/ Sec), and the fluidity (workability) of each composition was measured.

[0037]

[Table 1] * 1) Daikin Industries, Ltd. (peroxide vulcanizing fluororubber), trade name Daiel * 2) Can Carb, THERMAX N-990 * 3) Triallyl isocyanurate * 4) Daikin Industries, Ltd. (peroxide addition) Sulfurized low-viscosity fluororubber), product name DAI-EL

From the results shown in Table 1 and FIGS. 1 and 2, it was confirmed that the fluororubber composition of the present invention was excellent in roll processability and fluidity, and also had good mechanical strength and elongation.

Further, from the results shown in FIGS. 1 and 2, the shear rate is 10 s.
Looking at the temperature reaching ec ⁻¹ , the composition of the present invention has a temperature lower than that of the comparative composition by 50 ° C. or more, and it is needless to say that the viscosity at the same temperature is 100 ° C.
It can be seen that it has fallen to less than a factor of one. Therefore, it was confirmed that the composition of the present invention can be processed at extremely low temperature or at high speed by adopting extrusion processing, calendering, mold molding or the like for molding by viscous flow. Particularly, the composition of the present invention which is easy to scorch, for example, low temperature vulcanization type peroxide (for example, benyl peroxide, 2,4).
It was also found that when prepared as a dichlorobenzoyl peroxide) blending composition, an amine blending composition, and a quaternary aluminum-based polyol blending composition, high processing safety can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the results of fluidity measurement of a fluororubber composition obtained in Examples and Comparative Examples using a flow tester.

FIG. 2 is a graph showing the results of fluidity measurement of a fluororubber composition obtained in Examples and Comparative Examples using a flow tester.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhisa Osawa 1 Hitomi, Osamu, Matsuida-cho, Usui-gun, Gunma Prefectural Silicone Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Noriyuki Koike Matsui, Usui-gun, Gunma Tamachi Daiji Hitomi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Takashi Matsuda Matsuda-cho, Gunma Prefecture Usui-gun Hitomi 1 10 Shin-Etsu Chemical Industrial Silicone Electronic Materials Research Center ( 72) Inventor Hirokazu Yamada 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (1)

[Claims] 1. A fluorine containing (1) an unvulcanized fluororubber, (2) a fluorine-containing organosilicon compound represented by the following general formula (I), and (3) a vulcanizing agent. Rubber composition. [Chemical 1]