JPS6116911A - Fluororesin composition crosslinkable with radiation - Google Patents

Abstract

PURPOSE:To provide the titled composition giving a molded article having excellent appearance, and free from dissipation of crosslinking accelerator in extrusion molding, by compounding a triallyl isocyanurate prepolymer to an ethylene- fluoroolefin copolymer. CONSTITUTION:(A) An ethylene-fluoroolefin copolymer (e.g. ethylene-tetrafluoroethylene copolymer) or its mixture with a fluorine-containing elastomer (preferably tetrafluoroethylene-propylene copolymer) is mixed with (B) a prepolymer (preferably 5-100-mer) of triallyl isocyanurate. A molded article having especially excellent appearance can be produced by homogeneously mixing the compound B with a fluorine-containing elastomer, and introducing the mixture together with an ethylene-fluoroolefin copolymer to an extruder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a fluororesin composition that can be crosslinked by irradiation with radiation such as an electron beam.

[Prior art] Ethylene-fluoroolefin copolymers generally have excellent mechanical properties and processability among fluororesins, as well as excellent electrical properties, chemical resistance, and heat resistance, and have a well-balanced property. It is the material.

For this reason, it is used in various fields, including as a material for covering electric wires, as well as in the form of films and tubes.

However, when placed in a high-temperature atmosphere that exceeds the melting point, it deforms due to external force, and there is a limit to its use at high temperatures.

In order to improve this, it is known to perform crosslinking by irradiating with radiation such as an electron beam, but crosslinking and collapse proceed simultaneously due to radiation irradiation, making it impossible to achieve sufficient crosslinking efficiency.

Therefore, attempts have been made to improve the crosslinking efficiency by adding a crosslinking promoter such as an allyl type compound.

[Problems to be Solved by the Invention] However, if a crosslinking accelerator is simply added and extruded, the crosslinking accelerator and fluororesin will be separated due to decomposition and local aggregation due to extrusion at high temperatures. There is a problem in that this causes a reaction and the appearance of the molded product becomes rough, making it impossible to obtain a good product.

Furthermore, since the molding temperature of the ethylene-fluoroolefin copolymer is quite high, the crosslinking accelerator volatilizes during extrusion molding, which is unfavorable from an environmental hygiene standpoint.

The present invention has been made based on the above, and aims to provide a fluorine resin composition that allows molded products with good appearance to be obtained and in which the crosslinking accelerator does not volatilize during extrusion molding. It is something.

[Means for Solving the Problems] The fluororesin composition of the present invention includes a prepolymer of triallylisocyanurate in a mixture of an ethylene-fluoroolefin copolymer or an ethylene-fluoroolefin copolymer and a fluorine-containing elastomer. It is important to include it.

In the present invention, examples of the ethylene-fluoroolefin copolymer include ethylene-tetrafluoroethylene copolymer and ethylene-chlorotrifluoroethylene copolymer, which may be used alone or in combination of two or more. Available for use.

In the present invention, it is also possible to use a mixture of (1) a tyrene-fluoroolefin copolymer and a fluorine-containing elastomer.

The fluorine-containing elastomer is not particularly limited;
Tetrafluoroethylene-propylene copolymer, vinylidene butyride-hexafluoropropene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene butyrate-pentafluoropropene copolymer, polyfluoro Alkyne group-containing acrylate elastomer, polyfluoroalkyne group-containing polysiloxane elastomer, tetrafluoroethylene-gonylidene fluoride-propylene copolymer, tetrafluoroethylene-
Ethylene-isobutylene copolymer, ethylene-hexafluoropropene copolymer, tetrafluoroethylene-butene-1 copolymer, tetrafluoroethylene-ethyl vinyl ether copolymer, fluorine-containing phosphonitrile elastomer, Examples include tetrafluoroethylene-fluorovinyl ether copolymers.

Among these, a tetrafluoroethylene-propylene copolymer is particularly suitable, and the molar ratio of tetrafluoroethylene/propylene is 9515 to 30/70,
In particular, it is preferable to select from the range of 90/1o to 45155.

In the present invention, the prepolymer of triallyl isocyanurate is a dimer or more polymerized monomer of triallyl in cyanurate, and is a polymer having a relatively high molecular weight and containing a double bond in the molecule.

In this case, it is preferable to use a polymer not exceeding 200 mers from the viewpoint of processability, and a suitable one is from 5 to 100 mers.

The amount added is 1 to 20 parts by weight per 100 parts by weight of the ethylene-fluoroolefin copolymer or the mixture of the ethylene-fluoroolefin copolymer and the fluoroelastomer.
A range of heavy M parts is common.

In the present invention, in addition to the above-mentioned components, stabilizers, fillers (carbon black, silicic acid fillers, etc.), colorants, antioxidants, lubricants, etc. can also be blended as appropriate.

Examples of the stabilizer include lead oxide, magnesium oxide, calcium oxide, aluminum oxide, titanium oxide, antimony oxide, phosphorus pentoxide, and the like.

It has been confirmed through experiments by the inventor that a molded product obtained by introducing a predetermined amount of each of the camphor components described above into an extruder and extruding the molded product while melt-kneading has an extremely smooth appearance.

In particular, by uniformly mixing a fluorine-containing elastomer and a triallylisocyanurate prepolymer in advance and introducing this mixture into an extruder together with an ethylene-fluoroolefin copolymer, a molded product with a particularly excellent appearance can be obtained. Confirmed.

[Example] With the various components in Table 1 in the proportions shown on each side, the temperature in barrel zone 1 was 260°C, and the temperature in barrel zone 2 was 260°C.
Extrusion Ill (40 m /
m 1L/D=20, compression ratio=3), and then,
A conductor having an outer diameter of 0.8# was coated by extrusion to a thickness of 0.2#, and then irradiated with a 10M rad electron beam to create a crosslinked insulated wire.

In Examples 1 to 3, the tetrafluoroethylene-propylene copolymer, triallylisocyanurate prepolymer, fine particle silica, and titanium oxide were mixed in advance and then introduced into the extruder, and in Comparative Example 1, the tetrafluoroethylene-propylene copolymer The copolymer, triallylisocyanurate, particulate silica, and titanium oxide were premixed and then introduced into the extruder.

The evaluation results for the insulated wires on each side are shown in the lower column of Table 1.

Note that the appearance after extrusion is the result of visually observing the appearance of the insulated wire, and the heat deformation rate is the result of measurement at 330°C in accordance with J15C3005.

Rice 1 Asahi Glass Co., Ltd. 77o7COPCB8A Rice 2
Allied Chemical Co., Ltd. Harler 300 rice 6 Asahi Glass Co., Ltd. Afras 150E rice 4 Nippon Aerosil f stock)
-;' As is clear from Table 1 of Erosil R972, all of Examples 1 to 3 within the scope of the present invention had good extrusion appearance, good thermal deformation rate, and no volatilization of the crosslinking accelerator.

[Effects of the Invention] As explained above, the present invention provides a composition in which a prepolymer of triallylisocyanurate is contained in an ethylene-fluoroolefin copolymer or a mixture of an ethylene-fluoroolefin copolymer and a fluorine-containing elastomer. This makes it possible to obtain a crosslinked molded product with excellent mechanical properties at high temperatures and a good appearance. Further, the volatilization of the crosslinking accelerator during extrusion is eliminated, and good environmental hygiene can be maintained.

Claims (3)

[Claims] (1) A radiation crosslinkable doublet characterized by containing a prepolymer of triallylisocyanurate in an ethylene-fluoroolefin copolymer or a mixture of an ethylene-fluoroolefin copolymer and a fluorine-containing elastomer. Base resin composition. (2) Claim 1, characterized in that the ethylene-fluoroolefin copolymer is selected from ethylene-tetrafluoroethylene copolymer or ethylene-chlorotrifluoroethylene copolymer. radiation crosslinkable fluororesin composition. (3) The fluorine-containing elastomer is a radiation crosslinkable fluorine resin composition according to claim 1, wherein the fluorine-containing elastomer is a tetrafluoroethylene-propylene copolymer.