JPH0625500A - New fluororubber composition - Google Patents

Abstract

PURPOSE:To obtain a fluororubber compsn. excellent in high-temp. strengths by compounding a fluororubber, a fluororesin, and a fluorinated thermoplastic elastomer. CONSTITUTION:A fluororubber compsn. comprises 100 pts.wt. fluororubber (e.g. one based on a vinylidene fluoride-hexafluoropropylene copolymer), 1-100 pts.wt. fluororesin (e g. a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and a fluorinated thermoplastic elastomer {e.g. one represented by the formula: Q[(A-B-...)I]n (wherein Q is a residue formed by removing I atoms from an iodide compd.; A, B,... are each a polymer-chain segment and at least one of these segments is a fluorine-contg. segment; and I is an I atom removed from the iodide compd.) and having a mol.wt. of at least 30,000} in an amt. of 5-100 pts.wt. based on 100 pts.wt. the fluororesin. The compsn. is excellent in high-temp. strengths.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluororubber composition.

[0002]

2. Description of the Related Art Fluorine rubber is used in various applications because it has excellent properties (for example, excellent heat resistance and oil resistance). However, the fluororubber has a drawback that its strength is greatly reduced when heated.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the hot strength of fluororubber.

[0004]

The gist of the present invention is (a)
100 parts by weight of fluororubber, (b) fluororesin 1-1
And 100 parts by weight of (c) the fluororesin (b) and 5 to 100 parts by weight of the fluorine-containing thermoplastic elastomer.

The fluororubber (a) is a fluorinated elastic polymer and includes any conventionally known fluororubber. Representative fluororubbers (a) include vinylidene fluoride / hexafluoropropylene type (preferable molar ratio of vinylidene fluoride: hexafluoropropylene = 45-95: 55-5), vinylidene fluoride / tetrafluoroethylene / hexa. Fluoropropylene system (preferred molar ratio of vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene =
45-90: 1 to 35: 5 to 50), vinylidene fluoride / chlorotrifluoroethylene type, tetrafluoroethylene / propylene type, hexafluoropropylene / ethylene type, perfluoroalkyl vinyl ether
(Including those containing a plurality of ether bonds) / olefin (tetrafluoroethylene, ethylene, etc.) type (preferable molar ratio of perfluoroalkyl vinyl ether / olefin = 15 to 75:85 to 25), fluorosilicone type, fluoro Fluororubber such as phosphazene type may be used. The fluororubber (a) has an iodine atom or a bromine atom bonded to its polymer chain in order to enhance the vulcanization reactivity (for example, JP-A-53-125491 and JP-B-53-53).
-4115 and JP-A-59-20310). The molecular weight of fluororubber is 3,000 to 1,2.
It is preferably 00,000.

The fluororesin (b) is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer.
(Hereinafter referred to as PFA), tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter referred to as FEP),
Tetrafluoroethylene / hexafluoropropylene /
Perfluoroalkyl vinyl ether copolymer (hereinafter,
EPE), tetrafluoroethylene / ethylene copolymer (hereinafter referred to as ETFE), polychlorotrifluoroethylene (hereinafter referred to as PCTFE), a homopolymer of vinylidene fluoride and an unsaturated compound copolymerizable with vinylidene fluoride. Copolymer with (hereinafter PVD
(F) and so on.

[0007] PFA is tetrafluoroethylene and has the formula: CF ₂ = CF-O-Rf (wherein Rf has 1 carbon atom).
It represents a fluoroalkyl group of 10 to 10. ) Is at least one copolymer of fluoroalkyl vinyl ether, preferably tetrafluoroethylene 99.5
~ 92 wt% and fluoroalkyl vinyl ether 0.5
.About.8% by weight. FEP preferably consists of 96-87% by weight of tetrafluoroethylene and 4-13% by weight of hexafluoropropylene. ETFE
Preferably consists of 90 to 74% by weight of tetrafluoroethylene and 10 to 26% by weight of ethylene.

The fluororesin (b) may contain other monomers as long as the essential properties of these polymers are not impaired. Other monomers include vinylidene fluoride,
Tetrafluoroethylene, hexafluoropropylene,
Perfluoroalkyl vinyl ether, perfluoro
(C ₁ -C ₁₀ ) alkyl ethylene, perfluoro (C ₁ -C
₁₀ ) alkyl allyl ether, and the formula: CF ₂ ═CF [OCF ₂ CFX (CF ₂ ) _m ] _n OCF ₂ (C
F ₂ ) _p Y (wherein, X is a fluorine or trifluoromethyl group, Y is a halogen, m is 0 or 1 (provided that m is 1, X is limited to fluorine), n is a number from 0 to 5, p is a number from 0 to 2.)
The compound shown by is mentioned.

The fluorine-containing thermoplastic elastomer (c) is
It preferably comprises at least one elastomeric polymer chain segment and at least one non-elastomeric polymer chain segment, at least one of which is a fluoropolymer chain segment. In particular, it is preferable that the weight ratio of the elastomeric polymer chain segment to the non-elastomeric polymer chain segment is 40 to 95: 5 to 60. The molecular weight of the fluorinated thermoplastic elastomer (c) is preferably 30,000 to 1,600,000.

As a particularly preferred example of the fluorine-containing thermoplastic elastomer (c), a chain composed of two or three polymer chain segments, an iodine atom present at one end of the chain and the other end of the chain It consists of a residue obtained by removing at least one iodine atom from an existing iodide compound, and is one kind (when the chain is composed of two kinds of polymer chain segments) or one kind or two kinds (three kinds of chains) of the polymer chain segment. Of the polymer chain segment) of (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) [including those containing a plurality of ether bonds. The same applies hereinafter] / tetrafluoroethylene /
Vinylidene fluoride (molar ratio 15-75: 0-85:
0-85) selected from polymers, molecular weight 30,000
~ 1,200,000 elastomeric polymer chain segments, the remainder of said polymer chain segments being (3)
Vinylidene fluoride / tetrafluoroethylene (molar ratio 0 to 100: 0 to 100) polymer and (4) ethylene / tetrafluoroethylene / hexafluoropropylene, 3,3,3-trifluoropropylene-1,2-trifluoromethyl -3,3,3-trifluoropropylene-
1 or perfluoro (C ₁ -C ₃ alkyl vinyl ether) (molar ratio 40-60: 60-40: 0-30) polymer selected from non-elastomeric polymer chain segments with a molecular weight of 3,000 to 400,000. And a fluorine-containing thermoplastic elastomer having a weight ratio of the elastomeric polymer chain segment to the non-elastomeric polymer chain segment of 40 to 95: 5 to 60. A preferable fluorine-containing thermoplastic elastomer (c) is disclosed in JP-A-53-53.
3495 gazette.

A typical structure of the fluorine-containing thermoplastic elastomer is, for example, the formula: Q [(AB -...) I] n [wherein, Q is a residue obtained by removing an iodine atom from an iodide compound, A, B, ... are polymer chain segments
(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 Q bonds. ], And at least 1 from a chain composed of at least two kinds of polymer chain segments, an iodine atom bonded to both ends thereof, and an iodide compound.
It consists of the residues excluding iodine atoms as essential constituents.
Thus, the at least two kinds of polymer chain segments are different from adjacent polymer chain segments (for example, those having different structures or compositions of the monomer units constituting the same), home,
At least one type is a fluoropolymer chain segment and is composed of at least one hard segment and at least one soft segment. Preferably, each polymer chain segment has a molecular weight of 3,000 or more, but at least one polymer chain segment has a molecular weight of 30,000 or more and excludes the so-called telomer region. Further, the residue obtained by removing at least the iodine atom from the iodide compound,
When the iodide compound has a polymerizable double bond, the iodide compound may have a monomer constituting the polymer chain segment or a substituent derived from the iodide compound. These fluorine-containing thermoplastic elastomers usually contain 0.001 to 10% by weight of iodine atoms. However, of course, those in which iodine atoms are removed from these thermoplastic elastomers by a reaction or which are substituted with other atoms or atomic groups are also included. The hard segment of the fluorinated thermoplastic elastomer (c) preferably has the same composition as the fluororesin (b).

The amount of fluororesin (b) is the amount of fluororubber (a)
1 to 100 parts by weight, preferably 3 to 100 parts by weight
-60 parts by weight. When the amount is less than 1 part by weight, the degree of improvement in the hot strength is low. If it is more than 100 parts by weight, the hardness becomes too high and the rubber elasticity is lost. The amount of the fluorine-containing thermoplastic elastomer (c) is 5 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the fluororesin (b). If the amount is less than 5 parts by weight, the effect as a compatibilizer is not exhibited. If more than 100 parts by weight is added, no further effect can be obtained.

When only the fluororesin (b) is blended with the fluororubber (a), the strength under heat is relatively improved, but the strength and elongation in the normal state are low. The fluorinated thermoplastic elastomer (c) functions as a compatibilizing agent for the fluororubber (a) and the fluororesin (b), and improves the physical properties in the normal state.

The composition of the present invention can be produced by mixing the fluororubber (a), the fluororesin (b) and the fluoroplastic elastomer (c).
A temperature above the melting point of the fluororesin (b), for example 180 to 4
Mix at 00 ° C. The mixing can be performed by a mixing roll, a kneader, a Banbury mixer, or the like.

The fluororubber composition of the present invention is vulcanized. Depending on the application, vulcanization may not be necessary. As the vulcanizing agent, an organic peroxide compound,
A polyhydroxy compound / vulcanization accelerator, a polyamine compound, etc. can be used. When vulcanizing with these vulcanizing agents, known vulcanizing methods such as peroxide vulcanization, polyol vulcanization, and polyamine vulcanization can be adopted. Further, additives such as a crosslinking aid and a reinforcing agent may be added. The crosslinking aid is preferably used particularly in the case of peroxide vulcanization, and examples of the crosslinking aid include triallyl compounds (for example, triallyl cyanurate and triallyl isocyanurate) and diallyl compounds (for example, diallyl phthalate). is there. Examples of reinforcing agents are carbon black, silica, talc and the like.

Vulcanization can be carried out under ordinary vulcanization conditions of fluororubber. For example, after the composition for vulcanization is kneaded, it is put in a mold, and at 100 to 200 ° C, 20 to 100 kg / cm.
Press vulcanization is carried out by holding at ^{2 to 5} to 180 minutes, and then oven vulcanization is carried out by holding in a furnace at 150 to 300 ° C. for 0 to 50 hours to obtain a vulcanized rubber.

The present invention will be specifically described below with reference to Examples and Comparative Examples.

Example 1 10 parts by weight of a fluororesin (VP-830, polyvinylidene fluoride manufactured by Daikin Industries) and 2 parts by weight of a fluorine-containing thermoplastic elastomer (T-630, an end block manufactured by Daikin Industries is polyvinylidene fluoride). Thermoplastic elastomer) in a Toyo Seiki Seisakusho Labo Plastomill at 200 ° C. for 20 minutes at a rotor rotation speed of 2
Mixed at 0 rpm. Next, 90 parts by weight of fluororubber (G
-902, iodine-containing fluororubber (vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene terpolymer) manufactured by Daikin Industries, Ltd. was added, and 200
The mixture was mixed at 40 ° C. for 40 minutes to obtain a fluororubber composition. In the fluororubber composition, the amounts of MT-carbon, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (Perhexa 2.5B, manufactured by NOF CORPORATION), and triallyl isocyanurate shown in Table 1 were added. (TAIC) (manufactured by Nippon Kasei) was kneaded with an open roll to obtain a vulcanizing composition. After vulcanizing the vulcanizing composition at 160 ° C. for 10 minutes,
Oven vulcanization was performed at 0 ° C. for 4 hours to form a sample having a thickness of 2 mm. Using this sample, 100% modulus, tensile strength, elongation, tear strength and hardness were measured under normal conditions and after heat aging (200 ° C. × 72 hours). The physical properties were also measured during heating. Measurement of physical properties
It was performed according to JIS K6301. Using a 12.7 mm thick sample obtained by vulcanizing under the same conditions,
The compression set was measured under% compression (200 ° C. × 72 hours). The results are shown in Table 2.

Examples 2-6 and Comparative Examples 1-2 G-902, VP-803, T-630 in the amounts shown in Table 1
The same procedure as in Example 1 was repeated except that and MT carbon was used. The results are shown in Table 2.

[0020]

[Table 1] Ratio 1 Ratio 2 Real 1 Real 2 Real 3 Real 4 Real 5 Real 6 G-902 100 80 90 80 80 80 80 60 VP-830-20 10 20 20 20 20 40 T-630--2 1 2 4 8 8 MT carbon 20 10 20 10 10 10 10 5 Perhexa 2.5B 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TAIC 4 4 4 4 4 4 4 4

[0021]

[Table 2] Ratio 1 Ratio 2 Real 1 Real 2 Real 3 Real 4 Real 5 Real 6 Normal 100% modulus 45 91 74 90 97 91 93 202 Tensile strength 229 154 235 232 243 262 269 309 309 Elongation 287 210 261 236 239 270 274 277 Tear strength 31 40 33 38 39 41 39 63 Hardness 74 81 80 81 81 80 80 89 Heat aged 100% Modulus 44 88 77 85 90 85 83 168 Tensile strength 208 152 236 243 227 223 244 270 Elongation 288 218 296 277 271 264 303 279 Hardness 74 81 80 80 81 78 79 89 Heat strength 100 ℃ Tensile strength 65 55 84 79 83 93 92 120 (Retention rate) 28 36 36 34 34 35 34 39 Tear strength 17 24 18 21 21 22 24 30 (Retention) Rate) 55 60 55
55 54 54 62 48 150 ℃ Tensile strength 38 31 45 48 49 50
61 (Retention rate) 17 20 19 20 19 19 20 Tear strength 12 17 15 13 14 14 19 (Retention rate) 39 43 39 33 34 36 30 Compression set (%) 18 21 18 24 24 22 21 33

Example 7 20 parts by weight of a fluororesin (EP-620, an ethylene / tetrafluoroethylene copolymer manufactured by Daikin Industries, Ltd.) and 4 parts by weight of a fluorine-containing thermoplastic elastomer (T-530,
Endoblock manufactured by Daikin Industries Co., Ltd. is an ethylene / tetrafluoroethylene copolymer thermoplastic elastomer) 2 at 260 ° C in a Toyo Seiki Seisakusho Labo Plastomill.
The mixture was mixed for 0 minutes at a rotor rotation speed of 20 rpm. Next, 100 parts by weight of fluororubber (G-901H, iodine-containing fluororubber manufactured by Daikin Industries, Ltd.) was added and mixed at 260 ° C. for 40 minutes to obtain a fluororubber composition. The fluororubber composition contained MT-carbon in the amount shown in Table 3 and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (Perhexa 2.5B, manufactured by NOF Corporation), triallyl isocyanurate. (TAIC) (manufactured by Nippon Kasei) was kneaded with an open roll to obtain a vulcanizing composition. After vulcanizing the vulcanizing composition at 160 ° C. for 10 minutes,
Oven vulcanization was performed at 0 ° C. for 4 hours to form a sample having a thickness of 2 mm. Using this sample, 100
The% modulus, tensile strength, elongation and tear strength were measured. The physical properties were also measured during heating. Measurement of physical properties
It was performed according to JIS K6301. Using a 12.7 mm thick sample obtained by vulcanizing under the same conditions,
The compression set was measured under% compression (200 ° C. × 72 hours).

Examples 8-9 and Comparative Examples 3-4 G-901H, EP-620 and T- in the amounts shown in Table 3.
The same procedure as in Example 7 was repeated except that 530 was used. The results are shown in Table 3.

[0024]

[Table 3] Ratio 3 Ratio 4 Actual 7 Actual 8 Actual 9 G-901H 100 100 100 100 100 EP-620-20 20 20 40 T- 530--4 8 8 MT Carbon 20 20 20 20 20 Perhexa 2.5B 1.5 1.5 1.5 1.5 1.5 TAIC 4 4 4 4 4 Normal 100% modulus 65 78 76 73 216 Tensile strength 193 165 179 207 254 254 Elongation 210 200 220 260 140 Tear strength 22 30 31 30 40 Heat strength 100 ℃ Tensile strength 58 74 72 71 125 (Retention rate) 30 45 40 34 49 Tear strength 15 18 17 17 28 (Retention rate) 68 59 55 56 70 Compression set (%) 17 42 43 49 42

[0025]

The fluororubber composition of the present invention has excellent hot strength.

Claims (1)

[Claims] 1. (a) 100 parts by weight of fluororubber,
(B) Fluororesin 1 to 100 parts by weight, and (c) 5 to 100 parts by weight of fluororesin (b) to 100 parts by weight of a fluorine-containing thermoplastic elastomer.