JPH0859941A - Fluoropolymer composition - Google Patents

Abstract

PURPOSE: To obtain a fluoropolymer composition excellent in mechanical property, moldability, flexibility, etc., and useful as a thermoplastic elastomer and a flexible resin by dispersing a fluorine-containing elastomer crosslinked body having a specific fluororesin. CONSTITUTION: This composition is obtained by dispersing (B) a crosslinked body of a fluorine-containing elastomer (preferably tetrfluoroethylene/propylene- based copolymer) with a size having <=1μm average particle diameter into (A) a matrix of a thermoplastic fluororesin capable of being melt-molded (preferably tetrafluoroethylene/ethylene-based copolymer). Furthermore, the composition contains preferably 10-95wt.% of the component A and 90-5wt.% of the component B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluoropolymer composition having excellent flexibility, which comprises a thermoplastic fluororesin and a fluoroelastomer crosslinked product.

[0002]

Fluorine-containing resins are excellent in heat resistance, chemical resistance, mechanical properties and electrical properties, but are poor in flexibility because they are crystalline polymers. On the other hand, the fluorine-containing elastomer has high flexibility, but its mechanical properties are lower than those of the resin, and unless it is vulcanized, it cannot be practically used as a molded product, and it takes time to mold.

Therefore, it has been attempted to achieve both moldability and flexibility by vulcanizing only the fluorine-containing elastomer component using a composition of a fluorine-containing resin and a fluorine-containing elastomer (Japanese Patent Laid-Open Publication No. Sho. 61-57641). Further, in the same publication, as a method for producing such a composition, a dynamic vulcanization method comprising vulcanizing the fluorine-containing elastomer while melting and blending the thermoplastic fluorine-containing resin and the fluorine-containing elastomer is proposed. ing.

However, the above-mentioned dynamic vulcanization method has a problem that it is substantially difficult to finely control the particle size of the vulcanized rubber produced, and the above-mentioned dynamic vulcanization method is also recognized. The composition obtained in (1) had insufficient mechanical properties and moldability, and had problems such as a large permanent set.

[0005]

The object of the present invention is to solve the above problems, that is, a fluoropolymer composition having sufficient mechanical properties and excellent moldability and flexibility. Is provided.

[0006]

As a result of intensive studies to solve the above problems, the inventors have found that the vulcanized rubber particles are 1 μm.
It was found that a composition having a size of m or less and dispersed in a resin has sufficient mechanical properties, moldability, and good permanent set, and completed the present invention.

That is, the present invention is characterized in that a crosslinked fluoroelastomer is dispersed in a matrix of a melt-moldable thermoplastic fluororesin with an average particle size of 1 μm or less. It is a composition.

In the fluoropolymer composition of the present invention, the content of the melt-moldable thermoplastic fluororesin in the fluoropolymer composition is preferably 10 to 95% by weight. Further, the fluoropolymer composition of the present invention,
Melt-moldable thermoplastic fluorine-containing resin 10 to 95% by weight
And 90 to 5% by weight of the fluorine-containing elastomer crosslinked product.

The thermoplastic fluorine-containing resin in the present invention is required to be melt-moldable. That is, the resin must be capable of measuring the melt index or volume flow rate described in ASTM-D-3159 at a temperature higher than the melting point. A thermoplastic fluororesin that can be melt-molded at a temperature at which deterioration of the fluoroelastomer used is not a problem is preferable. Of the usual fluorine-containing resins, all fluorine-containing resins except polytetrafluoroethylene resin can be adopted.

The fluorine-containing resin used in the present invention is tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride,
Chlorotrifluoroethylene, perfluoro (alkyl vinyl ether) (However, the alkyl group has 1 to 1 carbon atoms.
8 Obtained by polymerizing an ethylenically unsaturated compound containing at least one fluorine-containing monomer (excluding the case of using tetrafluoroethylene alone), and having a fluorine content of 35% by weight or more. Is preferred. If the fluorine content is too low, the original heat resistance and chemical resistance of the fluoropolymer cannot be obtained. Fluorine content 5
A fluorine-containing resin of 0% by weight or more is more preferably adopted.

Examples of the ethylenically unsaturated compound include ethylene, propylene, and
Alternatively, alkyl vinyl ethers and (perfluoroalkyl) ethylenes may be mentioned.

Specific examples of the fluorine-containing resin include tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoro (propyl vinyl ether) copolymer, and chloro. A trifluoroethylene / ethylene-based copolymer is preferable, and a tetrafluoroethylene / ethylene-based copolymer is particularly preferable. Further, there is no problem even if a mixture of a plurality of fluorine-containing resins is used.

Further, a suitable fluorine-containing resin is selected also in combination with the below-mentioned fluorine-containing elastomer.
For example, when the fluorine-containing resin or the fluorine-containing elastomer is a polymer having many vinylidene fluoride units, the polarity is exhibited. Therefore, as the fluororesin and the fluoroelastomer, the fluoropolymer composition obtained by selecting and combining those having vinylidene fluoride units or those not having the same units has uniform and good physical properties. Preferred for.

The fluorine-containing elastomer used in the present invention is tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether) (provided that the alkyl group is ,
It has 1 to 12 carbon atoms. Those obtained by polymerizing an ethylenically unsaturated compound containing at least one fluorine-containing monomer selected from (1) are preferable. Examples of the ethylenically unsaturated compound include ethylene, propylene, alkyl vinyl ethers, and (perfluoroalkyl) ethylenes in addition to the above-mentioned fluorine-containing monomer.

Specifically as the fluorine-containing elastomer,
Vinylidene fluoride / hexafluoropropylene copolymer, tetrafluoroethylene / propylene copolymer,
A tetrafluoroethylene / perfluoro (alkyl vinyl ether) type copolymer and a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene type copolymer are preferable. These copolymers may be further copolymerized with other copolymerizable components. The molar ratio of polymer units of tetrafluoroethylene / propylene / another copolymerizable unsaturated compound is 30 to 80/20 to 55/0.
Polymers of -40 are preferred. The fluorine content of these fluorine-containing elastomers is usually 50 to 65% by weight.
Is preferred. If the fluorine content is too small, the heat resistance and chemical resistance will not be sufficient, and if it is too large, the elasticity will decrease.

The fluorine-containing elastomer of the present invention is
Pre-crosslinked particulate material. The fluorine-containing elastomer crosslinked product in the form of particles can be obtained by polymerization by allowing a copolymerization monomer having two or more ethylenically unsaturated groups to coexist during polymerization. During the polymerization reaction, the ethylenically unsaturated groups in the comonomer are incorporated into the growing polymer chain. At this time, by incorporating the ethylenically unsaturated groups in the copolymerized monomer into separate polymer growth chains,
A fluorine-containing elastomer crosslinked product is formed during the polymerization.

Examples of the copolymerizable monomer having two or more ethylenically unsaturated groups include butadiene, isoprene, pentadiene, hexadiene, divinyl ether, allyl vinyl ether, butenyl vinyl ether,
Examples include divinylbenzene. A part or all of these compounds fluorinated can also be used. From the viewpoint of reactivity during polymerization, divinyl ether, allyl vinyl ether and butenyl vinyl ether are preferred. The amount used depends on the reactivity so that 0.1 to 10 mol% is introduced into the polymer, and it may be charged during the polymerization.

The crosslinked fluoroelastomer particles are obtained by impregnating the fluoroelastomer obtained by emulsion polymerization in the form of a latex with a vulcanizing agent, a vulcanization aid, etc.
It can be obtained by vulcanization or irradiation with radiation or the like.
After the polymerization, the vulcanized elastomer may be finely pulverized to obtain a particulate fluorine-containing elastomer crosslinked product.

As the vulcanization method, bisphenol AF,
Polyol vulcanization by combination of acid acceptor and onium salt, peroxide vulcanization by combination of organic peroxide and polyfunctional unsaturated compound, amine vulcanization by polyamine compound, epoxy vulcanization by epoxy group, ionic vulcanization etc. Well-known elastomer vulcanization methods can be adopted.

The crosslinked fluoroelastomer and the fluororesin thus obtained are preferably 5 to 90% in the former case.
The composition is obtained by blending in an amount of 95% by weight, the latter is 95 to 10% by weight, particularly preferably the former is 10 to 80% by weight and the latter is 90 to 20% by weight.

The method for producing the composition having a fine phase structure of the crosslinked fluoroelastomer in the matrix of the fluororesin of the present invention is, for example, a fine fluoroelastomer obtained from a latex crosslinked during emulsion polymerization. A method of blending particles with a fluororesin can be adopted. Further, a method of polymerizing a fluorine-containing resin with a similarly cross-linked fluorine-containing elastomer latex as a seed can also be adopted. Further, a method of blending a fluorinated elastomer obtained by crushing a vulcanized elastomer with a fluororesin after the polymerization is also included.

In the method using a fluorine-containing elastomer crosslinked during the polymerization, the size of the crosslinked elastomer particles is determined by the diameter of the emulsion polymerization latex, and a finer dispersion state is obtained as compared with the mechanical vulcanization method in which the particles are mechanically dispersed. It is preferable because it can be obtained.

As the polymerization method, known methods such as emulsion polymerization, solution polymerization and suspension polymerization can be adopted. Particularly, in emulsion polymerization, fluorine-containing elastomer fine particles can be formed at the time of polymerization,
It is preferable because there is no need for a step such as pulverization later, a fluorine-containing elastomer particle size is small, and a relatively narrow particle size distribution can be obtained.

The composition of the fluorine-containing resin and the fluorine-containing elastomer crosslinked product of the present invention thus obtained has a wide composition range of the fluorine-containing resin and the fluorine-containing elastomer.
Since the crosslinked fluorine-containing elastomer particles are dispersed very finely, it has moldability and flexibility and is particularly excellent in permanent set.

[0025]

【Example】

[Reference Example 1] Deoxidized water 1 in a 2 liter autoclave
000 g, t-butanol 100 g, ammonium perfluorooctanoate 6.0 g, ammonium persulfate 5.
0 g, sodium hydrogenphosphate 23.5 g, sodium hydroxide 2.5 g, iron-tetraethylenediamine complex 0.2
Charge g. After replacing the inside of the autoclave with nitrogen, 100 g of tetrafluoroethylene and 3.5 g of propylene are charged. The temperature is maintained at 30 ° C. with stirring, and a sodium hydroxymethanesulfinate aqueous solution is injected under pressure.

When the reaction starts and the pressure starts to decrease, tetrafluoroethylene / propylene (56
/ 44 (molar ratio)) while charging a mixed gas of 1,4-butanediol divinyl ether to 3.5 mol% with respect to the total number of moles of tetrafluoroethylene / propylene mixed gas introduced. Continue the reaction for 6 hours while adding.

The 1,4-butanediol divinyl ether reacts and is incorporated into the growing polymer chain.
At this time, 2 of 1,4-butanediol divinyl ether
One vinyl group is incorporated into different polymer chains to produce a fluoroelastomer having a crosslinked structure. After completion of the reaction, the monomer gas was purged, and the number of polymerized units of tetrafluoroethylene / propylene / 1,4-butanediol divinyl ether was 54 / 42.5 / 3.5 (molar ratio). Concentration is 16.6%
Obtained a latex. According to IR analysis, no vinyl group derived from 1,4-butanediol divinyl ether was found. The obtained latex was coagulated using calcium chloride as a salting-out material, washed with water and dried to obtain Elastomer 1.

[Examples 1 to 3 (Examples)] Polymerization units of tetrafluoroethylene / ethylene / (perfluorobutyl) ethylene were 58/39/3 (molar ratio), and AST
The resin 1 having a melt index of 40 according to MD-3159 and the crosslinked elastomer 1 shown in Reference Example 1 are shown in Table 1.
The various ratios (parts by weight) shown in Table 1 were melt mixed at 250 ° C. for 5 minutes to obtain a composition comprising a fluororesin and a fluoroelastomer. The tensile strength, elongation, permanent elongation (at 100% elongation) and average particle diameter of the crosslinked elastomer were measured for these compositions, and the results in Table 1 were obtained. Further, the phase structure of these compositions was extremely fine, and the fluorine-containing elastomer crosslinked product had an average particle diameter of 0.1 μm and was dispersed in the composition.

[Examples 4 to 6 (Comparative Example)] Resin 1 and 100
Unvulcanized elastomer having an epoxy group and a Mooney viscosity ML _{1 + 10} at 50 ° C. of 50 and polymerized units of tetrafluoroethylene / propylene / glycidyl vinyl ether of 54.8 / 43.0 / 2.2 (molar ratio). 2 was melt blended at various ratios (parts by weight) shown in Table 1 for 2 minutes at 270 ° C. Subsequently, ammonium benzoate was added as a vulcanizing agent, and dynamic vulcanization was performed at 270 ° C. for 3 minutes. Various physical properties were measured as in Example 1, and the results shown in Table 1 were obtained. The composition had a large permanent elongation. The phase structure of the composition has a large average particle size of the fluorine-containing elastomer crosslinked product,
It was 1.5 to 2 μm.

[0030]

[Table 1]

[0031]

EFFECTS OF THE INVENTION By dispersing a crosslinked fluoroelastomer having a particle size of 1 μm or less in a thermoplastic fluororesin, a thermoplastic elastomer or a soft resin having sufficient mechanical properties, molding and good permanent set properties. A fluoropolymer composition that is useful as

Front page continued (72) Inventor Haruhisa Miyake 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Central Research Laboratory, Asahi Glass Co., Ltd.

Claims (4)

[Claims] 1. A fluorine-containing polymer composition characterized in that a cross-linked body of a fluorine-containing elastomer is dispersed in a matrix of a melt-moldable thermoplastic fluorine-containing resin with an average particle diameter of 1 μm or less. 2. The fluoropolymer composition according to claim 1, wherein the content of the melt-moldable thermoplastic fluororesin in the fluoropolymer composition is 10 to 95% by weight. 3. The fluorine-containing elastomer is a tetrafluoroethylene / propylene-based copolymer.
The fluoropolymer composition of. 4. The fluoropolymer composition according to claim 1, wherein the melt-moldable thermoplastic fluororesin is a tetrafluoroethylene / ethylene copolymer.