JPH0737551B2 - Fluorine rubber vulcanizing composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a fluororubber vulcanizing composition for vulcanizing a polyol.

[Prior Art] As a formulation for vulcanizing fluororubber, a polyol vulcanization formulation is known as a formulation excellent in vulcanizate characteristics such as compression set. For example, as a vulcanization accelerator, a formulation using a quaternary phosphonium salt (JP-A-47-191), a formulation using a quaternary ammonium salt (JP-B-2-38072), a general formula In addition, a quaternary ammonium salt was added to the composition, and an amount (<0.1Phr) of 1,8-diazabicyclo [5.4.0] that did not substantially vulcanize the fluoroelastomer was added.
Prescription using Undecen-7 (Japanese Patent Publication No. 56-29696, Japanese Patent Publication No.
57-20333) etc.

Further, as a fluorine-containing elastomer having excellent engine oil resistance, an elastic copolymer in which vinylidene fluoride, tetrafluoroethylene and propylene are copolymerized is known.
However, the elastic copolymer (1) has extremely low vulcanizability as compared with other fluorine-containing elastomers, and when the vulcanization system of other fluorine-containing elastomer is adopted, good vulcanizability cannot be obtained. There was a problem.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems of the prior art, that is, vinylidene fluoride and tetrafluoride having excellent engine oil resistance. It is intended to provide a novel composition for vulcanizing a fluororubber comprising an elastic copolymer obtained by copolymerizing ethylene and propylene.

[Means for Solving Problems] The present invention has been made to solve the above-mentioned problems, and is a) an elastic copolymer obtained by copolymerizing vinylidene fluoride, ethylene tetrafluoride and propylene b) Divalent metal hydroxide and / or oxide c) polyhydroxy aromatic compound d) at least 2 selected from different groups of the following compound groups
Vulcanization accelerator which is a combination of species (a) Inorganic or organic acid salt of 1,8-diazabicyclo [5.4.0] undecene-7 (R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each alkyl having 1 to 20 carbon atoms,
An aralkyl or aryl group, X ⁻ is a halogen ion or OH ⁻ ) is provided.

The elastic copolymer (a) in the present invention is a copolymer obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene. Further, the copolymerization ratio, vinylidene fluoride, tetrafluoroethylene and propylene are respectively 10-60, 20-60, 20-50 mol%, vulcanizability, rubber physical properties of the vulcanized rubber, It is preferable in terms of mechanical properties and resistance to engine oil.

Further, in the production of (a) the elastic copolymer, various polymerization methods such as bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization of a predetermined amount of monomer can be adopted, and a free radical initiator is used. The catalyst polymerization method, ionizing radiation polymerization method, redox polymerization method, etc. can be appropriately adopted.

Examples of the b) divalent metal hydroxide and metal oxide include hydroxides and oxides of magnesium, calcium, lead, zinc and the like. The amount of these metal hydroxides and oxides used is 1 per 100 parts by weight of the fluorine-containing elastic copolymer.
-20 parts by weight, preferably 2-10 parts by weight are used.

c) As the polyhydroxy aromatic compound, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) perfluoropropane [bisphenol AF], hydroquinone, catechol, Examples thereof include resorcin, 4,4′-dihydroxydiphenyl, and 2,2-bis (4-hydroxyphenyl) butane, and preferably bisphenol A, bisphenol AF, hydroquinone and the like are used. These may also be in the form of alkali metal salts or alkaline earth metal salts. The polyhydroxy aromatic compound is used in an amount of 0.5 to 10 parts by weight, preferably 0.5 to 6 parts by weight, based on 100 parts by weight of the fluorine-containing elastic copolymer.

d) It is important to use, as a vulcanization accelerator, a combination of at least two selected from the following different compound groups.

(A) Inorganic or organic acid salt of 1,8-diazabicyclo [5.4.0] undecene-7 (R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each alkyl having 1 to 20 carbon atoms,
Aralkyl or aryl group, X ⁻ is a halogen ion or OH ⁻ ) For example, as the inorganic or organic acid salt of (8) 1,8-diazabicyclo [5.4.0] undecene-7 above, 1,8-diazabicyclo [ 5.4.0] undecene-7 p-toluenesulfonate (V-CATSA506), 1,8-diazabicyclo [5.4.0] undecene-7 octylate (V-CATSA-
102) and the like. Also Examples of the quaternary ammonium or phosphonium salt of tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride, allyltributylphosphonium chloride, allyltributylphosphonium bromide, benzyltributylphosphonium Chloride, benzyltrioctylphosphonium bromide, 8-methyl-
1,8-diazabicyclo [5.4.0] -7-undecenium chloride, 8-ethyl-1,8-diazabicyclo [5.4.0]-
7-undecenium bromide, 8-benzyl-1,8-diazabicyclo [5.4.0] -7-undecenium chloride, and the like.

Further, as a combination, (i) a combination of at least one inorganic or organic acid salt of 1,8-diazabicyclo [5.4.0] undecene-7 and at least one salt of (b) to (d). For example, 1,8-diazabicyclo [5.4.0] undecene-7 p-toluenesulfonate and tetrabutylammonium bromide, or 8-benzyl 1,8-diazabicyclo [5.4.0] -7-undensenium A combination of chloride is preferred.

The amount of these vulcanization accelerators used is 10% by weight of the fluorine-containing elastic copolymer 10.
0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, are used per 0 parts by weight.

To the composition of the present invention, carbon black, fine silica, clay, reinforcing agents such as talc, other fillers, other fillers, pigments, antioxidants, stabilizers and the like which are conventionally used in the production of vulcanized rubber are added. , May be mixed.

In producing the composition of the present invention, a fluorine-containing elastic copolymer, a polyhydroxy aromatic compound, a vulcanization accelerator, a divalent metal hydroxide and / or oxide, and other additives as necessary. It is desirable to mix them sufficiently uniformly. Such mixing can be performed by a rubber kneading roll or Banbury mixer which has been conventionally used. Working conditions during mixing are not particularly limited, but usually
By kneading at a temperature of about 30 to 80 ° C. for about 10 to 60 minutes, the additive composition can be sufficiently dispersed and mixed in the fluorine-containing elastic copolymer.

Further, such an additive formulation is appropriately dissolved and dispersed in a solvent,
It is also possible to use a suspension solution. Furthermore, so-called wet mixing is also possible, in which the mixing is carried out from the beginning into the medium.
In such a case, a solution-form compound can be obtained by using a mixer such as a roll, a ball mill or a homogenizer. In addition, it is desirable that the working conditions and operations during the mixing are performed by selecting the optimum conditions according to the kinds of the raw materials used and the compounding agents and the purpose.

The composition of the present invention can be formed into a sheet, a pipe, a rod, a tube, an angle, a channel, a drawing cloth, and a coating by a continuous molding processing method such as extrusion, transfer, roll coating, brush coating, and impregnation in addition to the usual die molding. It can be molded into a molded product such as a plate, and can also be molded into other shaped products and special molded products such as sponge rubber by various molding methods. The composition of the present invention thus molded and processed can be made into a vulcanized product by an appropriate vulcanizing means as described below. Thus, a vulcanized rubber product is obtained from the composition of the present invention.

In the present invention, the operation for vulcanization may be the operation that has been conventionally used conventionally.

For example, an operation of heating while pressurizing in a molding die may be adopted, and an operation of heating in a heating furnace or a steam pot after molding by an extrusion, calender roll or injection molding method may be adopted. Regarding the working conditions during vulcanization, it is desirable to select the optimum conditions according to the raw materials used and the compounding. The temperature during vulcanization is usually about 80 to 250 ° C, preferably about 120 to 200 ° C. The heating time is not particularly limited, but it is in the range of 1 minute to 3 hours, and preferably in the range of 5 minutes to 2 hours, depending on the combination of the polyhydroxy aromatic compound and the vulcanization accelerator. To be done.
If the heating temperature is increased, the heating time can be shortened. In addition,
Reheating treatment of the obtained vulcanized product can also be adopted, which is useful for improving physical properties. For example, 150-300 ℃,
Preferably, a reheat treatment at a temperature of 180 to 250 ° C. for about 2 to 25 hours can be adopted.

[Example] In the following examples and comparative examples, the vulcanization properties and vulcanizate properties of the compositions were measured as follows.

(1) Vulcanization characteristics A vulcanization curve was measured at 177 ° C using a JSR II type curlastometer manufactured by Imanaka Machinery Co., Ltd., and based on this, the minimum torque TRmin, maximum torque TRmax, effective torque ΔTR and vulcanization The start time t ₁₀ and the effective vulcanization time t ₉₀ were calculated.

(2) Mooney Scorch Shimane Seisakusho Co., Ltd. Mooney viscometer at a temperature of 125 ° C.
The Mooney scorch was measured on the L-type rotor, and the minimum Mooney viscosity V _{m was} increased to 5 points.
The point increase Prs was calculated after t ₅ and 25 minutes.

(3) Properties of vulcanizate A 1 mm thick sheet and a test piece for measuring compression set were molded using the composition for vulcanization at a pressure of 100 kg / cm ² G and a temperature of 170 ° C for 20 minutes, and then vulcanized at 230 ° C for 24 minutes. Time, secondary vulcanization was used as a test piece for various measurements.

J for tensile strength, elongation, 100% modulus and hardness
The compression set was measured according to IS K6301 according to ASTM-395-78.

<Example 1> A latex containing 30% by weight of a ternary copolymer in which the content ratio of each unit of vinylidene fluoride-tetrafluoroethylene-propylene is 32.4 / 42.1 / 25.5 (mol%) by emulsion polymerization method. Manufactured. This latex was dropped into a saline solution, allowed to aggregate, washed and dried to obtain a white elastic copolymer.

50 g (100 parts by weight) of this elastic copolymer, 2,2-bis (4-
Hydroxyphenyl) perfluoropropane [bisphenol AF] 0.75 g, 1,8-diazabicyclo [5.4.0] undecene-7 p-toluenesulfonate [SA506] 0.5
g, tetrabutylammonium bromide [TBAB] 0.25g,
3 g of Ca (OH) ₂ [carbit], MgO # 1502.5 g, sodium stearate 0.5 g and MT carbon 12.5 g were kneaded with a 4-inch roll to obtain a vulcanizing composition. The vulcanization properties, Mooney scorch and vulcanizate properties of the above composition are shown in Table 1.

<Examples 2 to 6> A vulcanizing composition was obtained in the same manner as in Example 1, except that the type and combination of the vulcanization accelerators were changed. The vulcanization properties, Mooney scorch and vulcanizate properties of the composition are shown in Table 1.

<Comparative Examples 1 to 8> In Example 1, the same operation was performed except that the type and combination of vulcanization accelerators were changed, and the vulcanizability, Mooney scorch and vulcanization of the obtained vulcanizing composition. The physical properties are shown in Table 2.

[Effects of the Invention] The composition of the present invention gives sufficient polyol vulcanizability to a fluorine-containing elastic copolymer excellent in engine oil resistance, which is insufficient in vulcanization in the conventional polyol vulcanization formulation. And is useful as a raw material for vulcanized rubber having excellent physical properties. In addition, based on excellent vulcanized physical properties such as heat resistance, engine oil resistance, and chemical resistance, crankshaft seals for automobile parts, o-rings around engines, gaskets, tubes, gaskets around radiators, tubes, and food products. It is also useful in a wide range of applications such as heat exchange gasket diaphragms, gaskets, and sealing materials in chemical plants.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08K 5/50 KJM C08L 23/14 KEC 27/18 KFY

Claims (2)

[Claims] 1. An elastic copolymer in which a) vinylidene fluoride, ethylene tetrafluoride and propylene are copolymerized, b) a divalent metal hydroxide and / or an oxide, c) a polyhydroxy aromatic compound, and d) the following compounds. At least 2 selected from different groups
Vulcanization accelerator which is a combination of species (a) Inorganic or organic acid salt of 1,8-diazabicyclo [5.4.0] undecene-7 (R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each alkyl having 1 to 20 carbon atoms,
An aralkyl or aryl group and X ⁻ is a halogen ion or OH ⁻ ). 2. The d) vulcanization accelerator is (a) at least one inorganic or organic acid salt of 1,8-diasabicyclo [5.4.0] undecene-7, and (b), (c), (b) The composition for vulcanizing fluororubber according to claim 1, which is a combination of at least one salt represented by (d).