JPS61133258A - Fluororubber composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition containing a fluororubber, a bivalent metal (hydr)oxide, a polyhydroxyl aromatic compound, and a salt of a specific aromatic sulfonic acid compound, etc., and providing a vulcanized rubber having excellent compression set resistance, mechanical properties, and moldability. CONSTITUTION:The objective composition can be produced by compounding (A) 100pts.(wt.) of a fluororubber, preferably a vinylidene fluoride- hexafluoropropene bipolymer, (B) 2-30pts. of a bivalent metal oxide or hydroxide, or ther mixture, or mixture of said oxide and/or hydroxide and a weak acid metal salt (e.g. barium stearate, etc.), (C) 0.1-10pts. of a polyhydroxyl aromatic compound, preferably bisphenol A, etc., and (D) 0.2-10pts. of the salt or mixture of the compound of formula I and/or II and an aromatic sulfonic acid compound (e.g. benzenesulfonic acid).

Description

[Detailed description of the invention] Industrial applications The present invention relates to a fluororubber composition.

BACKGROUND OF THE INVENTION In recent years, demand for fluororubber has increased in gaskets, sealing materials, diaphragms, pipes, and other fields due to its excellent heat resistance, chemical resistance, weather resistance, cold resistance, etc.

Vulcanization of such fluororubber is carried out using peroxide, radiation, polyamines, etc., but in practice, only polyamines such as hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexanediamine, etc. A method using however,
In vulcanization using polyamine, the resulting vulcanized rubber has good mechanical properties such as tensile strength and elongation, but has the disadvantage of high compression set. Later, a vulcanization method using polyol as a vulcanizing agent and an appropriate vulcanization accelerator was developed, and it became possible to obtain vulcanized rubber with low compression set. The disadvantage is that mechanical properties are inferior to those of the vulcanized rubber made from polyamine.

For this reason, Japanese Patent Publication No. 52-8863 proposes a vulcanized rubber that can simultaneously satisfy small compression set and good mechanical properties.

Problems to be Solved by the Invention However, the invention described in the above publication is still not fully satisfactory in terms of tensile strength, compression set, moldability, etc.

The present invention solves these conventional technical problems and aims to provide a vulcanized rubber that is excellent in compression set, mechanical properties, and moldability.

Means for solving the problem, that is, the present invention, consists of a fal fluororubber (composed of a BLZ-valent metal oxide, a divalent metal hydroxide, and a mixture of the metal oxide or metal hydroxide and a weak acid). (c) a polyhydroxy aromatic compound, and (dl) a salt of a compound (a) and/or (b) represented by the following general formula with an aromatic sulfonic acid compound, or The present invention provides a fluororubber composition containing a mixture of compounds (a) and/or (b) represented by the following general formula and an aromatic sulfonic acid compound.

The fluororubber that is component (a) of the present invention is a fluorinated rubbery copolymer, and examples of these copolymers include copolymers of vinylidene fluoride and other fluorine-containing olefins. Yes, vinylidene fluoride and hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride,
Examples include copolymers with at least one of perfluoro(methyl vinyl ether) and perfluoro(propyl vinyl ether).

Among these, vinylidene fluoride-hexafluoropropene binary copolymer and vinylidene fluoride-tetrafluoroethylene-hexafluoropropene terpolymer are preferred.

Further, these copolymer components may be further copolymerized with small amounts of vinyl compounds, olefin compounds, diene compounds, α,β-ethylenically unsaturated carboxylic acids, and the like.

Next, the (bl component of the present invention) is, for example, an oxide or hydroxide of magnesium, calcium, lead, zinc, etc., or a mixture of the oxide and hydroxide, or a mixture of the oxide and/or hydroxide. Examples of the metal salts of weak acids include salts of barium, sodium, potassium, lead, calcium, stearic acid, benzoic acid, carbonic acid, oxalic acid, phosphorous acid, etc. etc. can be mentioned as preferable ones.

The amount of component (b) used in the present invention is (2 to 30 parts by weight, preferably 5 to 30 parts by weight, based on 1,100 parts by weight of all fluorine).
If the amount is less than 2 parts by weight, the storage stability of the unvulcanized rubber compound will be poor and premature vulcanization will occur, which is undesirable. On the other hand, if it exceeds 30 parts by weight, the vulcanization rate will be extremely high and molding will be difficult. This is not preferable because it causes problems in terms of workability.

Next, as the polyhydroxy aromatic compound (C1 component) of the present invention, 2.2-bis(4-hydroxyphenyl)propane (bisphenol A), 2.2-bis(4-
Hydroxyphenyl) perfluoropropane (bisphenol AF), resorcinol, 1,3.5-trihydroxybenzene, 1.7-hydroxynaphthalene, 2.7
-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4.4'-dihydroxydiphenyl, 4.4'-
Dihydroxystilbene, 2,6-hydroxyanthracene, hydroquinone, catechol, 2,2-bis(
4-Hydroxyphenyl)butane (bisphenol B)
, 4.4-bis(4-hydroxyphenyl)valeric acid, 2
．． 2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4.4'-dihydroxydiphenyl sulfone, 4.4'-dihydroxydiphenylketone,
tri(4-hydroxyphenyl)methane, 3.3',
Examples include 5,5'-tetrabromobisphenol A and the like.

Among these polyhydroxy aromatic compounds, bisphenol A, bisphenol AF1 hydroquinone, and the like are particularly preferred. Moreover, such polyhydroxy aromatic compounds may be their alkali metal salts or alkaline earth metal salts.

In addition, the amount of such vulcanizing agent (C1 component ψ used is (a
l 0.1 to 10 parts by weight per 100 parts by weight of fluororubber,
Preferably, the amount is 0.5 to 5 parts by weight; if it is less than 0.1 part by weight, sufficient vulcanization effect cannot be obtained, resulting in a large compression set, which is undesirable. On the other hand, if it exceeds 5 parts by weight, the vulcanizing agent The effects of this will reach equilibrium.

Next, component +d) of the present invention is a salt of the compound (a) and/or compound represented by the above general formula and an aromatic sulfonic acid compound (hereinafter sometimes simply referred to as "salt"), or Compound (a) and/or (
(b) and an aromatic sulfonic acid compound (hereinafter sometimes simply referred to as "mixture").

Here, the compound represented by the general formula (a) is
(sometimes simply referred to as rDBUJ), and such compounds may have the hydrogen atom of the cyclic ring replaced by another atom or molecule.

In addition, the compound represented by the general formula (ron) is 1゜5-diaza-bicyclo(4,3,0)nonene-5 (hereinafter simply rD
(sometimes referred to as BNJ), and such a compound may be one in which the hydrogen atom of the cyclic ring is replaced by another atom or molecule, similar to the above-mentioned compound.

Furthermore, aromatic sulfonic acid compounds include benzenesulfonic acid, dodecylbenzenesulfonic acid, o, m, p-)luenesulfonic acid, 2.4-)luenedisulfonic acid, sulfanilic acid, naphthalenesulfonic acid, naphthionic acid, p-
-sulfobenzoic acid, etc., and these compounds may have a hydrogen atom in the cyclic ring substituted with another atom or molecule.

+d) When the component is a salt, for example, an aqueous solution of the compound represented by the general formula (a) and/or (b) is mixed with an aqueous solution containing the sulfonic acid compound in an approximately equivalent mole amount to the compound; It can be easily manufactured by adding .

When component (d) is a mixture, the mixing ratio of the compound represented by formula (a) and/or (b) and the sulfonic acid compound is usually 115 to 5/1 (7/1). .

In addition, (d+ acid component usage amount is 0.2 to 10 parts by weight, preferably 0.2 to 10 parts by weight per 100 parts by weight of fluorine rubber in the case of salt)
．． 5 to 3 parts by weight, and in the case of a mixture, the total amount is 0
．． 2 to 10 parts by weight, preferably 0.5. ~3 parts by weight. If the amount of the ldl component used is too small, vulcanization will be insufficient, while if it is too large, the rubbery properties may be impaired.

The composition of the present invention consists of (a) to (dl components),
If necessary, fillers and reinforcing agents such as carbon black, silica, clay, diatomaceous earth, and talc may be added as appropriate, and a small amount of one or more conventionally known vulcanizing agents may also be added ( Furthermore, plasticizers, colorants, etc. can also be added.

Examples of the method for vulcanizing the composition of the present invention include a method in which the composition is kneaded with rolls, placed in a mold and pressurized for primary vulcanization, and then secondary vulcanization. Here, the conditions for primary vulcanization are a temperature of 100 to 200°C and a time of 10 to 180°C.
The conditions for the secondary vulcanization are: temperature 150-300°C, time 0-30 hours.

Other vulcanization methods include vulcanization after preforming such as extrusion or injection, or preparing a dispersion or solution of an organic solvent and coating it on the surface of molded products such as fabrics, tubes, pipes, and tanks. There are many ways to vulcanize it.

Example Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, in the examples, parts are based on weight.

Examples 1 to 7, Comparative Examples 1 to 3 Fluorine rubber A containing vinylidene fluoride shown in Table 1
I (manufactured by Depon, Paiton E60) or A2 (manufactured by 3M, Tecnoflon NM) and various compounding agents are mixed on a two-roll mill with a roll temperature of approximately 25°C to produce unvulcanized rubber. A formulation was obtained. Using this formulation, the following various vulcanization tests were conducted, and the results are shown in Table 1 and FIG.

As is clear from Table 1, the composition of the present invention is excellent in compression set, mechanical properties, and moldability.

Moreover, according to the vulcanization curve showing the vulcanization behavior in FIG.
~2), a mixture of DBU and p-toluenesulfonic acid (
Examples 3-5) ,DBN,! - When using salts with p-1 luenesulfonic acid (Example 6) and mixtures of DBU and dodecylbenzenesulfonic acid (Example 7), D
Salt of BU and phenol (carbolic acid) (Comparative Example 1), DB
Compared to using U hydrochloride (Comparative Example 2) and DBU quaternary ammonium salt (Comparative Example 3), scorch is less likely to occur during handling before vulcanization, and the flow during primary vulcanization is It can be seen that the characteristics are also good.

[Vulcanization test]

(1) Testing method for vulcanization behavior An unvulcanized rubber compound was measured using a JSR Curastmeter model (manufactured by Japan Synthetic Rubber) at a temperature of 170°C and a frequency of 100c.
ps, amplitude ±1° C., and vulcanization behavior was measured from the change in stress of each sample over time.

(2) Test method for physical properties of vulcanized rubber ■ Vulcanization conditions for test piece Using a 100-ton hydraulic press, temperature 170°C, pressure 1
00 kgloJG for 20 minutes to perform primary vulcanization, and molded into sheets and blocks, respectively. Thereafter, it was taken out of the mold and heated in a furnace at a temperature of 230° C. for 24 hours to complete secondary vulcanization.

■Tensile test No. 3 dumbbells were punched out from sample sheets in accordance with JIS K6301, and 100% tensile stress, tensile strength, and elongation were measured using a Choper type tensile tester manufactured by Toyo Seiki ■.

■Hardness test Hardness (Hs) was measured using a spring-type JIS hardness tester manufactured by Shimadzu Corporation.

■Compression set test According to JIS K6301, leave in a furnace for 70 hours under 25% compression and pressure at a temperature of 200°C, then take it out of the furnace and let it cool at room temperature for 30 minutes, using a peacock-type rubber test sample sounding standard. The thickness was measured and the compression set was measured.

Effects of the Invention The vulcanized rubber obtained from the fluororubber composition of the present invention has superior mechanical properties such as compression set and tensile strength, as well as excellent processing and moldability, compared to conventional ones. In addition, the fluororubber products obtained by the present invention have excellent cold resistance, chemical resistance, and heat resistance as well as conventional fluororubber products, and have extremely great industrial significance.

[Brief explanation of drawings]

FIG. 1 is a vulcanization curve diagram of vulcanized rubber.

Claims (1)

[Claims] 1. A group consisting of (a) fluororubber, (b) a divalent metal oxide, a divalent metal hydroxide, and a mixture of the metal oxide or metal hydroxide and a weak acid. (c) a polyhydroxy aromatic compound, and (d) a salt of the compound (a) and/or (b) represented by the following general formula with an aromatic sulfonic acid compound; A fluororubber composition comprising: a mixture of compounds (a) and/or (b) represented by the following general formula and an aromatic sulfonic acid compound. (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼