JPS6281440A - Radiation-crosslinkable fluororesin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which does not cause evaporation of a crosslinking accelerator during molding and gives moldings having excellent appearances, by blending an ethylene/fluoroolefin copolymer or a mixture thereof with optionally a fluoroelastomer with a specified crosslinking accelerator. CONSTITUTION:1-20pts.wt. compd. (A) of the formula as a crosslinking accelerator and optionally, a stabilizer, an org. filler (e.g., carbon black), a colorant, an antioxidant, a lubricant, etc., are added to 100pts.wt. resin component which is an ethylene/fluoroolefin copolymer (B) selected from the group consisting of an ethylene/tetrafluoroethylene copolymer, an ethylene/chlorotrifluoroethylene copolymer, etc., or a mixture thereof with optionally a fluoroelastomer (C) (e.g., tetrafluoroethylene/propylene copolymer) in a weight ratio of B/C of 80-20/20-80.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] 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.

Further, 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 provides a fluororesin composition that can be crosslinked by radiation irradiation, which allows molded products with good appearance to be obtained, and which does not volatilize the crosslinking accelerator during extrusion molding. The purpose is to provide the following.

[Means for Solving the Problems] The fluororesin composition of the present invention has the following general formula: 4C\7C~ NO CH, -CH= CH2 Co/'□N=.

It is characterized by containing a compound represented by CH-CH=CH2 as a crosslinking promoter.

In the present invention, the ethylene-fluoroolefin copolymer is selected from ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, etc., and these may be used alone or in combination of two types. It can also be used.

Further, in the present invention, it is also possible to use a mixture of the above ethylene-fluoroolefin copolymer and a fluorine-containing elastomer.

The fluorine-containing elastomer is not particularly limited;
Tetrafluoroethylene-propylene copolymer, vinylidene butyrolyte-hexafluoropropene copolymer, vinylidene butyrate-chlorotrifluoroethylene copolymer, vinylidene butyrate-pentafluoropropene copolymer, polyfluoro Alkyne group-containing acrylate elastomer, polyfluoroalkyne group-containing polysiloxane elastomer, tetrafluoroethylene-hynylidene fluoride-propylene copolymer, tetrafluoro 1-7 ethylene-ethylene-isobutylene copolymer, ethylene- Hexafluoropropene copolymer, tetrafluoroethylene-butene-1 copolymer, tetrafluoroethylene-ethyl vinyl ether copolymer, fluorine-containing phosphonitrile elastomer, tetrafluoroethylene-
Examples include 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 90/10 to 45155.

The mixing ratio of the ethylene-tetrafluoroolefin copolymer and the fluorine-containing elastomer is preferably selected from the range of 80/20 to 20/80 in weight ratio of ethylene-tetrafluoroolefin copolymer/fluorine-containing elastomer.

The crosslinking accelerator used in the present invention is CH2-CH
= C1 (□ is a compound represented by C87C NO CH-CH= CH2- λ.

The amount added is 1 to 20 parts by weight per 100 parts by weight of the resin component.
Parts by weight ranges are common.

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

The inventor's experiments have confirmed that a molded product obtained by introducing predetermined amounts of the various components described above into an extruder and extruding them while melt-kneading has an extremely smooth appearance.

In particular, by uniformly mixing the fluorine-containing elastomer and the crosslinking accelerator represented by the above formula in advance and introducing this mixture into an extruder together with the ethylene-fluoroolefin copolymer, a molded product with particularly excellent appearance can be obtained. It has been confirmed that

[Example 1] The various components in Table 1 were mixed in the proportions shown on each side, and the temperature in barrel zone 1 was 260°C, and the temperature in barrel zone 2 was 260°C.
70T, barrel zone 3 temperature 280°C, crosshead temperature 320°C, die part temperature 320°C, screw rotation speed 15r, extruder set at p.
D=20. compression ratio = 3), extrusion coating was applied to the outer periphery of the conductor with an outer diameter of 0.8 mm to a thickness of 0.2 mm, and then 10M
A crosslinked insulated wire was created by irradiating it with a rad electron beam.

The crosslinked insulated wires on each side were evaluated for appearance after extrusion, thermal deformation rate, and volatilization of the crosslinking accelerator, and the results are shown in the lower column of Table 1.

The appearance after extrusion is based on visual observation.
The heating deformation rate is 3 at 300℃ according to JISC3005.
This is the result of measurement with a load of 00g applied.

As is clear from Table 1, Example 1 within the scope of the present invention
All of the results from 4 to 4 had good results.

Comparative Examples 1 and 2 using conventional crosslinking accelerators were inferior in extrusion appearance and heat deformation rate, and volatilization of the crosslinking accelerator was observed.

[Effects of the Invention] As explained above, according to the present invention, a crosslinked molded product with a good extrusion appearance and excellent mechanical properties at high temperatures can be obtained, and furthermore, volatilization of the crosslinking accelerator during manufacturing can be reduced. can be prevented.

Claims (3)

[Claims] (1) In an ethylene-fluoroolefin copolymer or a mixture of an ethylene-fluoroolefin copolymer and a fluorine-containing elastomer, a compound represented by the general formula, ▲mathematical formula, chemical formula, table, etc.▼ is used as a crosslinking accelerator. A fluororesin composition capable of crosslinking by radiation irradiation, comprising: (2) The ethylene-fluoroolefin copolymer is capable of crosslinking by radiation irradiation according to claim 1, wherein the ethylene-fluoroolefin copolymer is selected from ethylene-tetrafluoroethylene copolymer or ethylene-chlorotrifluoroethylene copolymer. fluororesin composition. (3) The radiation crosslinkable fluororesin composition according to claim 1, wherein the fluorine-containing elastomer is a tetrafluoroethylene-propylene copolymer.