JPH0297547A - Composition for vulcanizing fluororubber - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give a vulcanized fluororubber improved in heat resistance and decreased in compression set by adding a silver compound to a composition for vulcanizing an iodinated or brominated fluororubber with an organic peroxide. CONSTITUTION:100 pts.wt. iodinated or brominated fluororubber based on an elastic copolymer of vinylidene fluoride with at least one fluorinated ethylenically unsaturated monomer, desirably containing 20-85mol% vinylidene fluoride and 0.01-5wt.% iodine or 0.05-1.5wt.% bromine is blended with desirably about 0.1-5 pts.wt. organic peroxide [e.g., 2,5-dimethyl-2,5-di(t-butylperoxy) hexane], desirably 0.1-10 pts.wt. polyfunctional compound (e.g., triallyl isocyanurate) desirably having reactivity with a peroxy radical and a polymer radical, and desirably 0.1-50 pts.wt. silver compound which is, for example, a silver oxide, a silver salt of formula I (wherein Z is a halogen, NO3<-> or the like) or an organosilver salt of formula II (wherein R is a 1-20C alkyl, a 6-20C aryl or an aralkyl).

Description

Detailed Description of the Invention 1. Field of Industrial Application] The present invention relates to a composition for vulcanizing fluororubber, and more specifically, the present invention relates to a composition for curing fluororubber with peroxide containing iodine or bromine. This invention relates to a composition containing a silver compound for improvement.

[Prior Art] Fluororubber has the highest heat resistance among all rubbers, but there is a need for even higher heat resistance. In addition, since it is often used as a rail material, it is necessary to have a small compression set (C5).

[Problem to be solved by the invention] The composition for peroxide vulcanization of fluororubber is
Compared to T-type, chemical resistance and l? ! Although it has excellent m-characteristics, it has the disadvantage that C6 is slightly thicker than the polyol lll11 sulfur type.

The present invention further improves the heat resistance of a fluorine-containing oxide vulcanizing composition containing iodine or bromine,
Moreover, the aim is to provide a peroxide vulcanizing composition that can also reduce C5.

[Means for Solving the Problems] The present inventors have found that by blending a silver compound into peroxide-vulcanized fluororubber, it is possible to improve heat resistance compared to a composition to which no silver compound is added. At the same time, we have discovered that C8 can also be improved.

That is, the present invention provides (a) fluororubber containing iodine or bromine, (b) m
The present invention provides a composition for vulcanizing fluororubber, which is characterized by comprising a reception oxide, (c) a polyfunctional compound, and (d) a silver compound.

The fluororubber containing iodine or bromine, which is component (a) of the composition of the present invention, preferably contains 20 to 85 mol% vinylidene fluoride, more preferably 0.0 to 85 mol%.
It contains 1 to 5% by weight of iodine or 0.05 to 1.5% by weight of bromine, and is mainly composed of vinylidene fluoride and at least the fluorine-containing ethylenically unsaturated monomer of -i. It is made of an elastic copolymer with a body.

A typical fluororubber has the formula (a): CF*-CX Y [wherein X and Y each represent fluorine or chlorine. ] 50 to 95 mol% of repeating units derived from a fluoroolefin represented by (b) formula: % formula %] In the formula E, Rf is a perfluoroalkyl group having 1 to 12 carbon atoms, and X is fluorine or trifluoromethyl. group, n is 0~
An integer of 5, which does not represent 0 or l. 50 repeating units derived from perfluorovinyl ether represented by
~5 mol % and formula (c): % formula % [wherein, Rf' is a perfluoroalkylene group having 1 to 12 carbon atoms or a perfluorophenylene group, and Y is 100 O
R (Here, R is an alkyl group having 1 to 4 carbon atoms.)
, -CN, -F, -CI, -Br or -I, Q is 1
Represents an integer from ~3. It is a fluorine-containing copolymer consisting of 0 to 10 mol% of repeating units derived from an alkyl vinyl ether represented by the following formula, and preferably contains 0.01 to 5% by weight of iodine.

The introduction of iodine is, for example, formula.

A compound represented by Rr I x [wherein Rf is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group, and
In addition, the introduction of bromine can, for example, convert bromine-containing olefins into
This is carried out by allowing each of the above-mentioned monomers to coexist during copolymerization.

Regarding the manufacturing method of each of these fluororubbers, please refer to JP-A-51
This method is described in detail in Japanese Patent Publication No. 125491 and Japanese Patent Publication No. 54-1585.

Examples of the other fluorine-containing ethylenically unsaturated monomers include tetrafluoroethylene, chlorotrifluoroethylene,
Trifluoroethylene, vinyl fluoride, hexafluoropropylene, pentafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(edyl vinyl ether), perfluoro(propyl vinyl ether), formula: Xo(CFYCF, 0)CF=CF*
[Wherein, X is a perfluoroalkyl group having 1 to 3 carbon atoms,
ω-hydroperfluoroalkyl group or ω-chloroperfluoroalkyl group, Y represents hydrogen, chlorine, trifluoroethylene, difluoromethyl group or chlorodifluoromethyl group. ] Examples include fluoroalcoquin vinyl ethers represented by the following. Above all, fluororubber containing 15 to 50 mol % of perfluoro(methyl vinyl ether) and fluoroalcoquin vinyl ether represented by the above formula is preferred.

Further, for specific examples of the above-mentioned 1111x and bromine-containing olefins, see
2-iodoperfluoropropane, 1°4-short perfluorobutane, and 4-iodoperfluorobutene-1 are particularly preferred. etc., and the latter include promotrifluoroethylene, 4-bromo-3,
3,4.

Examples include 4-tetrafluorobutene-1.

The organic peroxide of component (b) may be any organic peroxide that generates peroxy radicals under vulcanization conditions, such as 1. ! -bis([-butylperokino)3.5.5-)
lyntylcyclohexane, 2.5-dimedylhexane-2
, 5-dihydroxyperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α°-bis(t-butylperoxy)
-p-diisopropylbenzene, 2,5-dimethyl-2
,5-no(t-butylperoxy)hexane, 2.5-
Dimethyl-2,5-di(t-butylperoxy)hexane 3, benzoyl peroxide, t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, [-butylperoxy) Examples include ochinemaleic acid and t-butylperoxyisopropyl carbonate.

Usually, the type and amount used are selected based on the amount of active -〇-〇-, decomposition temperature, etc., but in general, the amount used is
It is preferably used in a proportion of about 0.1 to 5 parts, preferably 0.5 to 3 parts, per 100 parts (parts by weight; the same applies hereinafter).

In principle, the polyfunctional compound of component (c) is effective as long as it has reactivity with peroxy radicals and polymer radicals, and the type is not particularly limited, but preferred examples include: , triallyl cyanurate, triallylisonanurate, triacryl formal, triacryl trimellitate, N, N'-s
-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalamide, tris(diallylamine)-S-triazine, triallyl phosphite, N,N-diallylacrylamide, and the like.

The amount used is preferably 0.1 to 10 parts, preferably 0.5 to 5 parts, per 100 parts of component (a).

The silver compound of component (d) includes silver oxide, -silver:
AgZ [In the formula, Z is a halogen, No, -, etc.] Silver salt, -killing% formula % [In the formula, R is a C1-C2o alkyl group or a C6-C2
゜Represents an allyl or aralkyl group. Examples include organic silver salts represented by the following. When these silver compounds are blended by co-coagulation with a fluororubber dispersion or blended after being adsorbed onto a filler, a greater effect can be obtained.

The amount of silver compound (d) used is preferably 0.1 to 50 parts, particularly 1 to 20 parts, per 100 parts of component (a).

In the composition of the present invention, the physical properties of the vulcanized rubber, especially C8
Pigments, extenders, lubricants, and other fillers can be added to the extent that they do not deteriorate the composition.

The fluororubber composition of the present invention can be vulcanized under normal fluororubber vulcanization conditions. For example, after kneading a fluororubber composition with a roll, it is put into a mold and heated to 100 to 200°C.
Press vulcanization is carried out by holding at 20-100 kg/cm'G for 5-180 minutes, followed by 150-30 kg/cm'G.
Vulcanized rubber is obtained by oven vulcanization by holding in a 0° C. oven for 0 to 40 hours.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 and Comparative Examples 1 to 3 The ingredients shown in Table 1 were thoroughly mixed on a rubber roll, and left to age day and night. After kneading this again on a roll, press processing @ (t60°C for XIO minutes) and open vulcanization (b80°C x 1 hour) were performed to obtain a sheet.

Regarding the obtained sorted vulcanized rubber, 100% tensile stress, tensile strength, roughness hardness, and rate of change after heat aging were measured. The measurement was based on the method described in JIS K6301.

Table 1 Example 2 and Comparative Examples 4 to 5 The silver oxide used in Example 2 was prepared as follows: 14.79 g of silver nitrate was placed in a 500-meter Meyer flask, 200 g of water was added to dissolve it, and Add 100 g of medium thermal carbon to the solution, stir well, and then add a 5% aqueous potassium hydroxide solution dropwise while stirring the system until pI becomes alkaline.Filter and wash with water until the filtrate becomes alkaline.
Repeat this process until it becomes neutral to obtain silver oxide dispersed and adsorbed on medium thermal carbon.

Using this silver oxide composite, the ingredients shown in Table 2 were kneaded in the same manner as in Example t and vulcanized to obtain a sheet. The physical properties of the obtained sheet are shown in Table 2.

2) Medium thermal carbon.

3) Triallylisocyanurate.

4) 2,5-dimethyl-2,5-di(t-butylperoxy)hexane 5) Rate of change after treatment at 250°C for 70 hours. however,
Hs is the change point.

Add 5% hydroxide power to Table 2 John in the specified ratio and stir thoroughly. Add Norum aqueous solution until ρto1 becomes 12, then add 5% potassium alum! This was washed with water and dried to obtain a co-agglomerate of fluororubber and silver oxide. The co-agglomerate of fluororubber and silver oxide was mixed with the formulations shown in Table 3. The ingredients were added, kneaded and vulcanized in the same manner as in Example 1 to obtain a sheet.

The physical properties of this notebook are shown in Table 3.

2) 2,5-dimethyl-2,5-di(L-butylperoxy)hexane Example 3 and Comparative Example 6

Claims (1)

[Claims] 1. Characterized by comprising (a) a fluororubber containing iodine or bromine, (b) an organic peroxide, (c) a polyfunctional compound, and (d) a silver compound. Composition for vulcanizing fluororubber.