JP3134534B2 - Fluoro rubber vulcanizing composition and vulcanized fluoro rubber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for vulcanizing a fluororubber and a vulcanized fluororubber, and more particularly, to a vulcanizing fluororubber for improving the roll processability of a fluororubber containing iodine during molding. The present invention relates to a composition and a vulcanized fluororubber obtained by vulcanizing the composition.

[0002]

2. Description of the Related Art Fluororubber is excellent in heat resistance, abrasion resistance, chemical resistance, solvent resistance, oil resistance, etc., and is used for tubes, sheets, films, and other molded products (eg, O-rings, sealing materials). It is used for various applications after being molded or coated and adhered to various substrates. Synthetic rubber is generally considered to be difficult to vulcanize. In order to facilitate vulcanization of fluororubber, it has been proposed to introduce an iodine atom into a part of the polymer chain of fluororubber (for example, Japanese Patent Publication No. 61-4 / 1986).
9327, U.S. Pat. No. 4,948,853, JP-B-63-41928, JP-A-60-221409, and JP-B-53-4115.

[0003] However, iodine-containing fluororubber has a problem that the roll processability is not sufficient in molding. That is, the rubber is rolled in a mastication or kneading step to impart plasticity or is mixed with other components. However, the above-mentioned iodine-containing fluororubber does not wind well around the roll, and the mastication or kneading is effective. There was a problem that it could not be performed.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the roll processability of iodine-containing fluororubber during molding without damaging the excellent properties of iodine-containing fluororubber.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, by adding a vinylidene fluoride resin and a fluorine-containing thermoplastic rubber to an iodine-containing fluororubber, The inventors have found that the object of the present invention can be solved, and that the mechanical properties of the obtained rubber are improved, thereby completing the present invention.

That is, the present invention provides (i) a fluorine-containing rubber containing 0.5 to 100 parts by weight of a vinylidene fluoride resin per 100 parts by weight of a fluorine-containing rubber containing iodine;
(iii) 100 parts by weight of vinylidene fluoride resin,
The gist is a composition for vulcanizing a fluororubber comprising 0 to 100 parts by weight of a fluorinated thermoplastic elastomer, and a vulcanized fluororubber obtained by vulcanizing the composition. Hereinafter, the present invention will be described in detail.

The iodine-containing fluororubber used in the composition of the present invention is obtained by binding 0.001 to 10% by weight of iodine to the fluororubber. Here, the fluororubber is a fluorinated polymer which has rubber elasticity at room temperature when vulcanized, and usually has a number average molecular weight exceeding 20,000. Conventionally known fluororubber compounds are included, and typical fluororubbers include vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, vinylidene fluoride / Chlorotrifluoroethylene copolymer, tetrafluoroethylene / propylene copolymer, hexafluoropropylene / ethylene copolymer, perfluoroalkyl vinyl ether (including those containing a plurality of ether bonds) / olefin (tetrafluoroethylene, (E.g., ethylene) copolymers, fluorosilicone rubbers, and fluorophosphazene rubbers. The iodine-containing fluororubber means that iodine is chemically bonded to carbon in the polymer chain of the fluororubber, and the amount of the iodine is about 0.001 to 10% by weight based on the whole polymer. , Preferably about 0.01 to 5% by weight. The carbon to which iodine is bonded is preferably the terminal of the polymer chain, but is not necessarily limited thereto, and may be carbon in the main chain, side chain, or branch point.

[0008] With respect to the method for producing the iodine-containing fluororubber, see JP-B-61-49327, US Pat.
No. 948853, JP-B-63-41928, JP-A-60-221409 and JP-B-53-4115.

The vinylidene fluoride resin used in the present invention includes a homopolymer of vinylidene fluoride and a copolymer of vinylidene fluoride as a main component and at least one other monomer copolymerizable therewith. And do not exhibit rubber elasticity even when crosslinked. Examples of the copolymerizable monomer include vinyl fluoride, ethylene trifluoride, ethylene tetrafluoride, propylene hexafluoride, and hexafluorobutene, but are not limited thereto.

The vinylidene fluoride resin is used in an amount of 0.5 to 100 parts by weight based on 100 parts by weight of the iodine-containing fluororubber.
Preferably, 1 to 50 parts by weight are added. If the amount is less than 0.5 part by weight, the effect of improving the roll processability, which is the object of the present invention, is not sufficient, and if it exceeds 100 parts by weight, the composition obtained by vulcanizing the composition loses its properties as a rubber.

The composition of the present invention contains a fluorine-containing thermoplastic rubber in addition to the iodine-containing fluorine rubber and the vinylidene fluoride resin. Thermoplastic rubber refers to a polymer that exhibits the properties of a vulcanized rubber at room temperature and is plasticized at high temperatures, but a fluorinated thermoplastic rubber has at least one elastomeric polymer chain segment (soft segment) and at least one polymer segment. Of non-elastomeric polymer chain segments (hard segments), at least one of which is a fluorinated polymer chain segment. In particular, those having a weight ratio of the elastomeric polymer chain segment to the non-elastomeric polymer chain segment of 40 to 95:60 to 5 are preferable.

Particularly preferred examples of the fluorine-containing thermoplastic rubber include a chain composed of two or three polymer chain segments, an iodine atom present at one end of the chain, and an iodide present at the other end of the chain. A residue obtained by removing at least one iodine atom from a compound,
One (if the chain consists of two polymer chain segments) or one or two of said polymer chain segments
(If the chain consists of three polymer chain segments)
(1) vinylidene fluoride / hexafluoropropylene or pentafluoropropylene / tetrafluoroethylene (molar ratio 45-90: 5-50: 0-35) polymer and (2) perfluoro (C ₁ -C ₃ alkyl vinyl ether) [ Also included are those containing a plurality of ether bonds. The same applies to the following.] / Tetrafluoroethylene / vinylidene fluoride (molar ratio: 15 to 75: 0 to 85: 0 to 85) polymer, which is an elastomeric polymer chain segment having a molecular weight of 30,000 to 12,000,000, and The remainder is (3) vinylidene fluoride / tetrafluoroethylene (molar ratio of 0 to 100: 0 to 10
0) polymer and (4) ethylene / tetrafluoroethylene / hexafluoropropylene, 3,3,3-trifluoropropylene-1,2-trifluoromethyl-3,3,3,
3-trifluoropropylene-1 or perfluoro
(C ₁ -C ₃ alkyl vinyl ether) (molar ratio 40 to 60:
60 to 40: 0 to 30) a non-elastomeric polymer chain segment having a molecular weight of 3000 to 400,000 selected from a polymer, wherein the weight ratio of the elastomeric polymer chain segment to the non-elastomeric polymer chain segment is from 40 to 95: 5. 60, a fluorine-containing thermoplastic rubber. Preferred fluorine-containing thermoplastic rubbers used in the present invention are described in JP-A-53-3495. The non-elastomeric polymer chain segment is preferably a vinylidene fluoride-based one in order to improve the compatibility with the vinylidene fluoride-based resin.

A typical structure of a fluorine-containing thermoplastic rubber is as follows:
For example, the formula: Q [(AB-...) I] n wherein Q is a residue obtained by removing an iodine atom from an iodide compound, and A, B,.
(However, at least one of them is a fluorine-containing polymer chain segment.), I represents an iodine atom released from the iodide compound, and n represents the number of bonds of Q. And a chain composed of at least two types of polymer chain segments, and at least one iodine atom and an iodide compound bonded to both ends thereof.
The residue excluding iodine atoms is an essential component.
Thus, the at least two types of polymer chain segments are mutually different from the adjacent polymer chain segments (for example, those having different structures and compositions of the monomer units constituting the polymer chain segments). home,
At least one is a fluorinated polymer chain segment, consisting of at least one hard segment and at least one soft segment. Preferably, each polymer chain segment has a molecular weight of at least 3,000, but at least one of the polymer chain segments has a molecular weight of at least 30,000, excluding the so-called telomer region. Further, a residue obtained by removing at least an iodine atom from the iodide compound is, when a polymerizable double bond is present in the iodide compound, a monomer constituting the polymer chain segment or any substitution moiety derived from the iodide compound. It can have. These fluorinated thermoplastic rubbers,
Usually contains 0.001 to 10% by weight of iodine atoms. However, of course, those obtained by removing iodine atoms from these thermoplastic rubbers by reaction or by replacing them with other atoms or atomic groups are also included.

In the fluororubber vulcanizing composition of the present invention, it can be considered that the fluorine-containing thermoplastic rubber functions to enhance the compatibility of the vinylidene fluoride resin with the iodine-containing fluororubber. The fluorine-containing thermoplastic rubber is added in an amount of 0 to 100 parts by weight, preferably 1 to 50 parts by weight, based on 100 parts by weight of the vinylidene fluoride resin. Even if it exceeds 100 parts by weight, as a compatibilizer,
No further effect can be obtained.

The mixing of the iodine-containing fluororubber, the vinylidene fluoride-based resin and the fluorinated thermoplastic rubber as components of the composition of the present invention is carried out, for example, as follows. (A) After mixing iodine-containing fluororubber, vinylidene fluoride resin, and fluorinated thermoplastic rubber in the form of a latex or suspension, respectively, they are coagulated and coprecipitated. (B) The above components are heated and melted at a temperature not lower than the melting point of each component, preferably 150 to 250 ° C, more preferably about 200 ° C, and mixed. If the mixing temperature exceeds 250 ° C., the rubber tends to deteriorate, which is not preferable. If the mixing temperature is lower than 150 ° C., the mixing becomes insufficient.

The rubber rubber vulcanizing composition of the present invention may contain ordinary rubber compounding chemicals, such as reinforcing agents, fillers, plasticizers, release agents, softeners, stabilizers, and extenders. .

A vulcanizing composition can be obtained by adding a known vulcanizing agent, such as a peroxide compound, a polyamine compound or a polyhydroxy compound, to the fluororubber vulcanizing composition of the present invention. Preferred are peroxide compounds, for example, 1,1-bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, 2,5-
Dimethylhexane-2,5-dihydroxy peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α′-bis (t-butylperoxy) -p-diisopropylbenzene, 2,5
-Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, benzoyl peroxide, t-butylperoxybenzene, Examples thereof include 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, and t-butylperoxyisopropyl carbonate. The amount of the vulcanizing agent is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the composition.

When an organic peroxide compound is used, a remarkable effect can be obtained by appropriately using a vulcanization aid or a co-vulcanizing agent. The vulcanization aid or co-vulcanization agent is effective in principle as long as it has a reaction activity for peroxy radicals and polymer radicals, and the type is not particularly limited. Preferred examples include triallyl cyanurate, triallyl isocyanurate, triacrylformal, triallyl trimellitate, N, N'-m-phenylenebismaleimide, dipropargyl terephthalate, diallyl phthalate, and tetraallyl terephthalamide. Can be The amount used is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the composition.

As a means for mixing these components, an ordinary open roll or the like may be used. The vulcanization of the fluororubber composition of the present invention can be carried out under ordinary vulcanization conditions for fluororubber. For example, after kneading a roll of a fluororubber composition,
Put in the mold, 20-100kg / c at 100-200 ° C
Press vulcanization is performed by holding at m ² G for 5 to 180 minutes, and then vulcanized rubber is obtained by performing open vulcanization by holding in a furnace at 150 to 300 ° C. for 0 to 40 hours.

The vulcanized fluoro rubber of the present invention is useful for packings, sealants, O-rings, automobile parts, general industrial parts, etc. due to its properties. Next, the composition of the present invention and the vulcanized product thereof will be described based on examples, but it is needless to say that the present invention is not limited to these examples.

[0021]

EXAMPLES In the examples, the physical properties of the vulcanized products were measured by the following methods. The 100% tensile stress (M100), tensile strength (T _B ), elongation (E _B ), hardness (HS), tear strength (TR), and permanent compression set (CS) were measured according to the method of JIS K6301.

Reference Example 1 An iodine-containing fluororubber was synthesized by the following method. 300
1500 ml of pure water and 7.5 g of ammonium perfluorooctanoate are placed in a 0 ml internal pressure resistant reaction tank, and the internal space is sufficiently replaced with a mixed gas of vinylidene fluoride (VdF) / hexafluoropropylene (HFP) (45/55 molar ratio). Thereafter, the pressure was increased to 14 kg / cm ² G. CF ₂ (C
0.5 ml of FClCF ₂ I) ₂ (25 ° C.) was injected, and the mixture was heated to 80 ° C. with stirring, and 10 ml of a 10% aqueous solution of APS was injected. The polymerization reaction starts immediately and a pressure drop occurs,
When reduced to 13 kg / cm ² G, VdF / HFP
(78/22 mole ratio) mixture again pressurized to 15 kg / cm ² G by gas, hereafter 13~15kg / cm ² G in this manner
The polymerization was continued while maintaining the pressure range. After 2 hours, the temperature was rapidly lowered and the pressure was released to terminate the polymerization. The product is a white, translucent dispersion with noticeable bubbling and a solids concentration of 11
% By weight. After freeze coagulation, washing with water and drying, the rubber obtained has an iodine content of 0.31% by weight and an intrinsic viscosity [η] = 0.34 (dl) using methyl ethyl ketone as a solvent.
/ G, 35 ° C).

Examples 1 to 6, Comparative Example 1 The iodine-containing fluororubber synthesized in Reference Example 1 (VdF / H
FP copolymer), polyvinylidene fluoride resin (Neoflon VDF VP830, manufactured by Daikin Industries, Ltd.), and fluorine-containing thermoplastic rubber (Daiel Thermoplastic T630, manufactured by Daikin Industries, Ltd.) by weight:
The mixture was mixed at a ratio of 10: 2 and heated and melted at 200 ° C. to form a blend. The iodine-containing fluororubber was added to this blend so that the ratio of the three components became the ratio shown in Table 1, and the mixture was roll-kneaded at room temperature for 0.5 hour using an open roll to obtain a composition of the present invention. . At this time, the kneading state (roll workability) was visually observed. For comparison, only the iodine-containing fluororubber compound was roll-kneaded in the same manner as described above, and the kneaded state was observed.

[0024]

[Table 1]

To 100 parts by weight of the composition thus obtained, 20 parts by weight of medium thermal carbon as a reinforcing agent and 2,5 dimethyl-2,5-di (t-butylperoxy) hexane] 1 as a vulcanizing agent Then, 0.5 parts by weight and 4 parts by weight of triallylisocyanurate were added, and the mixture was kneaded with an open roll at room temperature for 0.5 hours.

Next, the obtained kneaded dough was charged into a predetermined mold and pressed at a temperature of 160 ° C. under a pressure of 50 kg / cm ² for 10 minutes to obtain a sheet having a thickness of 2 mm. A No. 4 dumbbell was punched from this sheet, and the physical properties of the vulcanized product were examined. The obtained results are shown in Table 2 together with the results of roll workability during kneading. For comparison, a vulcanizate sample was tested in the same manner as described above except that the iodine-containing fluororubber (only) was used instead of the composition of the present invention. Table 2 also shows the results.

[0027]

[Table 2]

[0028]

As described above, the composition of the present invention can be easily wound around a roll during mastication or kneading, thereby improving the roll processability and facilitating the forming process.
The vulcanizability, which is a characteristic of iodine-containing fluororubber, is not adversely affected. It also has the advantage that the mechanical properties of the vulcanizate are improved.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 27/12-27/24 C08K 5/14

Claims (3)

(57) [Claims] (1) 0.5 parts per 100 parts by weight of iodine-containing fluororubber (ii) iodine-containing fluororubber
To 100 parts by weight of vinylidene fluoride resin, and (iii) 100 parts by weight of vinylidene fluoride resin.
A composition for vulcanizing a fluororubber comprising １００100 parts by weight of a fluorinated thermoplastic rubber. 2. The fluororubber vulcanizing composition according to claim 1, further comprising a fluororubber vulcanizing agent. 3. A vulcanized fluoro rubber obtained by vulcanizing the composition for vulcanizing a fluoro rubber according to claim 2.