JP6020200B2 - Fluorine-containing elastomer composition and insulated wire using the same - Google Patents

Description

  The present invention relates to a fluorine-containing elastomer composition and an insulated wire using the same.

  With respect to fluorine-containing elastomer compositions, the following techniques have been developed for the purpose of improving various physical properties.

  Patent Document 1 discloses a fluorine resin composition in which 0.01 part by weight or more of at least one compound of bismuth oxide, barium oxide, calcium oxide, calcium carbonate and the like is blended per 100 parts by weight of the fluorine resin. .

  Patent Document 2 has a coating layer of a composition containing 10 to 100 parts by weight of silane-treated calcium carbonate with respect to 100 parts by weight of a tetrafluoroethylene-propylene copolymer, and the coating layer is crosslinked. A fluorine-containing elastomer-coated cabtire cable is disclosed.

JP 63-89558 A JP-A-1-154404

  When a large amount of filler is added, if the particle size of the filler is small, the initial strength increases, but the heat resistance decreases. On the other hand, if the particle size of the filler is large, the heat resistance increases, but there is a problem that the initial strength is not improved.

  An object of the present invention is to provide a fluorine-containing elastomer composition excellent in mechanical strength such as tensile properties without impairing heat resistance and flexibility, and an insulated wire using the same as a material for an insulating layer. .

The fluorine-containing elastomer composition of the present invention comprises a copolymer of tetrafluoroethylene and propylene, and a filler having a structure in which silica and kaolinite are bonded and having a surface subjected to silane treatment. against coalescence 100 parts by weight filler Ri 20-100 parts by der, number average molecular weight of the copolymer is characterized by a 20,000 to 200,000.

  According to the present invention, a fluorine-containing elastomer composition having both heat resistance and mechanical strength and an insulated wire using the same can be provided.

  The present invention relates to an insulated wire having a fluorine-containing elastomer coating layer excellent in flexibility and heat resistance.

  From early on, the applicant focused on improving the insufficiency of flexibility, which has been regarded as a problem in the past, while maintaining the excellent heat resistance and flame retardancy of fluororesin insulated wires. Fluorine that not only has sufficient flexibility to sufficiently satisfy the amount of bending required in general electrical work, but also exhibits excellent properties such as high-temperature oil resistance and radiation resistance. We have succeeded in developing resin insulated wires. An example thereof is a fluorine-containing elastomer-coated cabtire cable described in Patent Document 2.

  Here, flexibility will be described.

  When performing a general electric work, for example, if the electric wire is hard in a narrow space, the electric wire is difficult to bend and the wiring operation is difficult. On the other hand, when the electric wire is soft and easy to bend, the wiring work becomes easy. Thus, a soft and easily bent electric wire can be called a flexible electric wire.

  Specifically, the fluorine-containing elastomer described in Patent Document 2 is mainly composed of a tetrafluoroethylene-propylene copolymer and, as described above, is excellent in heat resistance, oil resistance, chemical resistance and electrical properties. ing. From these physical properties, application to hoses, tubes, gaskets, packings, diaphragms, sheets, electrical insulation coatings and the like is greatly expected.

  A copolymer of tetrafluoroethylene and a C 2-4 α-olefin containing propylene may add a large amount of a filler such as calcium carbonate for the purpose of improving mechanical strength. It can be said that the addition amount is 60 parts by mass or more, but as described above, it is difficult to achieve both heat resistance and initial strength.

  Therefore, the fluorine-containing elastomer composition of the present invention has a structure in which a copolymer of tetrafluoroethylene and an α-olefin having 2 to 4 carbon atoms, silica and kaolinite are bonded, and the surface thereof is subjected to silane treatment. The filler is 20 to 100 parts by mass with respect to 100 parts by mass of the copolymer.

  In the present invention, the α-olefin having 2 to 4 carbon atoms which is copolymerized with tetrafluoroethylene to exhibit elastomeric properties is selected from propylene and butene-1 alone, and two types selected from ethylene, propylene, butene-1 and isobutene. The above combinations are exemplified, but propylene is preferable for achieving the object of the present invention.

  The tetrafluoroethylene-propylene copolymer (polymer component) includes, in addition to the main components tetrafluoroethylene and propylene, components copolymerizable therewith, such as ethylene, isobutylene, acrylic acid and its alkyl ester, fluorine. Vinyl chloride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, chlorotrifluoroethylene, perfluoroalkyl vinyl ether and the like may be appropriately contained.

  The tetrafluoroethylene-propylene-based copolymer is preferably selected so that the molar ratio of tetrafluoroethylene / propylene is in the range of 95/5 to 30/70, particularly preferably from the viewpoint of heat resistance, moldability, and the like. , 95/10 to 45/55 is preferable. Further, the content of components other than the main component added as appropriate is preferably selected from the range of 50 mol% or less, particularly 30 mol% or less.

The number average molecular weight of the tetrafluoroethylene-propylene copolymer is preferably 20,000 to 200,000 (2.0 × 10 ^{4 to} 2.0 × 10 ⁵ ) from the viewpoint of extrudability and mechanical strength. If the average molecular weight is too large, cracks are likely to occur in the molded article. On the other hand, if the number average molecular weight is too small, the mechanical strength tends to be insufficient. In this case, the number average molecular weight is adjusted by controlling the copolymerization reaction conditions such as monomer concentration, polymerization initiator concentration, monomer to polymerization initiator amount ratio, polymerization temperature, and chain transfer agent use. The molecular weight can be adjusted by a method of adjusting the molecular weight or by a method of reducing the molecular weight by, for example, producing a high-molecular-weight copolymer during the copolymerization reaction and subjecting it to heat treatment in the presence of oxygen.

  In this invention, it is a filler which has the structure which the silica and kaolinite couple | bonded with respect to 100 mass parts of above-described polymer components, Comprising: 20-100 mass parts which silane-treated the surface are added. When the filler is less than 20 parts by mass, there is no reinforcing effect. On the other hand, when the filler exceeds 100 parts by mass, the viscosity of the rubber composition (molten composition) becomes high and extrusion molding becomes impossible. Further, the amount of the filler is more preferably 20 to 60 parts by mass.

  There are various types of silane treatment, but aminosilane treatment or vinylsilane treatment is particularly preferred.

Here, the silane treatment is a general formula X-Si- (OR) ₃ (wherein X is a vinyl group, amino group, epoxy group, methacryl group, mercapto group, etc., and OR is a methoxy group or ethoxy group. A surface treatment for imparting a desired functional group to a target substance using a silane coupling agent represented by the following formula: The functional group on the surface obtained by subjecting the inorganic substance to aminosilane treatment is an amino group. Moreover, the functional group of the surface obtained by performing a vinyl silane process to an inorganic substance is a vinyl group. Therefore, the filler has a structure in which silica and kaolinite are bonded, and a functional group such as a vinyl group or an amino group is added to the surface of the filler via a silicon atom.

  In the present invention, various additives such as a crosslinking agent, a crosslinking aid, and an acid acceptor are blended in order to exhibit rubber elasticity. The crosslinking agent is preferably an organic peroxide, and the acid acceptor is preferably magnesium oxide.

  In the present invention, a crosslinking aid is added to increase the crosslinking reactivity, and examples of the crosslinking aid include triallyl isocyanurate, triallyl cyanurate, triallyl trimellitate, and tetraallyl pyromellitate. Allyl type compounds are particularly preferred.

  In the present invention, in addition to the above components, various additives such as other inorganic fillers, stabilizers, antioxidants, plasticizers and lubricants can be blended.

  Hereinafter, description will be made using examples.

(Examples and Comparative Examples)
Table 1 shows the components and evaluation results of the compositions of Examples 1 to 6 and Comparative Examples 1 to 7. The silica / kaolinite combination shown in the lower part of this table is an example of a filler having a configuration in which silica and kaolinite are combined.

  First, the raw materials of the composition shown in this table were kneaded using a roll, and the Mooney viscosity of the uniformly mixed composition was measured.

Next, this composition was extrusion coated to a thickness of 0.3 mm on the surface of a tin-plated copper stranded conductor having an outer diameter of 1.6 mm using a 40 mm extruder (L / D = 22), and then 13 kgf Crosslinking was carried out with steam of / cm ² for 3 minutes. Here, a 40 mm extruder uses what has the front part (cylinder 1) and rear part (cylinder 2) of a serial cylinder, Dies | dies: 100 degreeC, head: 80 degreeC, cylinder 1:80 degreeC, cylinder 2:80 Each temperature was set to ° C.

  A tin-plated copper stranded wire was drawn from the insulated wire produced as described above to obtain a tube shape, and the initial tensile characteristics and heat resistance of each test example were measured.

  The Mooney viscosity was measured at 130 ° C., and 50 or less capable of extrusion molding was regarded as acceptable. Regarding the initial tensile properties, the case where the tensile strength was 12 MPa or more and the elongation was 200% or more was regarded as acceptable.

  For heat resistance, the sample was taken out after being placed in a heat aging tester at 250 ° C. for 4 days, and tensile properties were measured. Then, the ratio of the tensile property after heat aging to the initial tensile property was calculated by the following formula: “residual rate (%) = (tensile property after heat aging / initial tensile property) × 100” and represented by the residual rate. The remaining rate was 80% or more.

  Examples 1 to 6 within the scope of the present invention all exhibit Mooney viscosity capable of extrusion molding, as well as high tensile properties and heat resistance.

  Examples 1, 2, 4 and 5 are cases where the amount of the filler is 20 to 60 parts by mass, and various evaluation results are further increased.

  In contrast, in Comparative Examples 1 and 3, the amount of filler in which silica and kaolinite are bonded is less than the range defined by the present invention, and the tensile properties are insufficient.

  In Comparative Examples 2 and 4, the addition amount of the filler in which silica and kaolinite are bonded exceeds the range defined by the present invention, the Mooney viscosity is high, and both the tensile properties and the heat resistance are insufficient.

  Comparative Examples 5-7 use the filler of a prior art. Comparative Example 5 has insufficient tensile properties and heat resistance, Comparative Example 6 has insufficient tensile properties, and Comparative Example 7 has insufficient heat resistance.

  In Comparative Example 6 (calcium carbonate: particle size 2 μm, no treatment), the tensile strength is not improved even when added up to 60 parts by mass, and it is difficult to improve the strength even when the amount added is increased.

  Further, Comparative Example 7 (calcium carbonate: particle size 0.1 μm, fatty acid treatment) is inferior in heat resistance even when added up to 60 parts by mass.

  It seems that the compatibility between mechanical strength and heat resistance, which is a problem of the prior art, can be solved by adding a small amount of calcium carbonate. However, if the addition amount of calcium carbonate is reduced, the extrudability is lowered. It is also difficult to reduce the cost.

  As described above, according to the present invention, a fluorine-containing elastomer composition having excellent mechanical strength and heat resistance can be provided.

Claims (8)

Comprising a copolymer of tetrafluoroethylene and propylene, and a filler having a structure in which silica and kaolinite are bonded and having a surface subjected to silane treatment, with respect to 100 parts by mass of the copolymer, filler Ri 20-100 parts by der, number average molecular weight of the copolymer is 20,000 to 200,000 fluorine-containing elastomer composition, which is a.   The fluorine-containing elastomer composition according to claim 1, wherein the filler is 20 to 60 parts by mass with respect to 100 parts by mass of the copolymer. Wherein the ratio of the content of tetrafluoroethylene and the propylene fluorine-containing elastomer composition according to claim 1, characterized in that the 95 / 5-30 / 70 on a molar basis.   2. The fluorine-containing elastomer composition according to claim 1, wherein the silane treatment is aminosilane treatment or vinylsilane treatment.   The fluorine-containing elastomer composition according to claim 1, further comprising at least one of a crosslinking agent and an acid acceptor. A copolymer of tetrafluoroethylene and propylene, and a filler having a structure in which silica and kaolinite are bonded and having a functional group added via a silicon atom to the surface thereof, and 100 parts by mass of the copolymer respect, the filler is Ri 20-100 parts by der, number average molecular weight of the copolymer is from 20,000 to 200,000 fluorine-containing elastomer composition, which is a. The fluorine-containing elastomer composition according to claim 6 , wherein the functional group is a vinyl group or an amino group. A wire comprising a conductor and the fluorine-containing elastomer composition according to any one of claims 1 to 7 , wherein a surface of the wire is covered with the fluorine-containing elastomer composition. Insulated wire.