JPH11209527A - Polyolefin resin composition and electric wire / cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin composition excellent in both low-temperature characteristics and heat resistance and to form an insulator or a jacket using a compound containing the same as a main component, thereby obtaining low-temperature characteristics and heat resistance. To obtain excellent wires and cables. SOLUTION: A crystalline polyolefin, a soft polymer, and an organic peroxide are blended to form a polyolefin resin composition having a plurality of crystal melting peaks at 150 ° C. or higher, and a compound containing the obtained polyolefin resin composition as a main component is prepared. Wires and cables are manufactured by using them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyolefin resin composition which is excellent in low-temperature properties and heat resistance and can provide a molded article having a good appearance, and is produced using a compound containing the polyolefin resin composition as a main component. Related to electric wires and cables.

[0002]

2. Description of the Related Art As a polyolefin for a polyolefin-based heat-resistant electric wire, a polyolefin which is chemically crosslinked with a peroxide or irradiated with an electron beam and crosslinked is mainly used. However, the production speed cannot be increased due to the crosslinking reaction, and a huge capital investment is required for constructing the crosslinking line.

On the other hand, when an attempt is made to manufacture a heat-resistant electric wire without cross-linking, it is conceivable to form an insulator or a jacket with a resin composition containing a polyolefin having a crystal melting point of 150 ° C. or higher as a main component. Such a polyolefin having a crystal melting point of 150 ° C. or more has poor bending properties at low temperatures, and cannot be applied to electric wires as it is.
Therefore, in general, a method has been adopted in which flexibility is imparted by blending a soft polyolefin to improve the bending characteristics at low temperatures. There is a disadvantage that the property is impaired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyolefin resin composition having improved bending characteristics at low temperature and excellent appearance of a molded product while maintaining heat resistance. This enables wires and cables with excellent heat resistance, low-temperature characteristics and appearance.

[0005]

Means for Solving the Problems To solve the above-mentioned problems, a study was made to actively cut the polyolefin molecular main chain having a high crystal melting point with an organic peroxide. As a result, polyolefin 3 having a crystal melting point of 150 ° C. or more was obtained.
0 to 70 parts by weight, 30 to 70 parts by weight of a soft polymer and an organic peroxide are essential components, and are melted and kneaded.
A polyolefin resin composition having a plurality of crystal melting peaks at 150 ° C. or higher in calorimetric measurement by SC is produced, and an insulator or a jacket is formed using a compound containing the obtained polyolefin resin composition as a main component. It has been found that by doing so, it is possible to obtain an electric wire or cable having excellent bending characteristics at low temperature while maintaining heat resistance.

The above polyolefin resin composition 10
By adding 0.1 to 5 parts by weight of maleic anhydride per 0 parts by weight, it was clarified that the resulting wire / cable had excellent product appearance.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The polyolefin resin composition of the present invention comprises 30 to 70 parts by weight of a polyolefin having a crystal melting point of 150 ° C. or more, 30 to 70 parts by weight of a soft polymer, and an organic peroxide as essential components. Wherein the soft polymer is selected from the group consisting of polyolefins, copolymers of olefins and other polymerizable monomers, and derivatives thereof.
A polyolefin resin composition comprising a kind or two or more kinds of polymers, wherein the composition has a plurality of crystal melting peaks in a region of 150 ° C. or more in a calorimetric measurement by DSC.

The electric wire / cable of the present invention is an electric wire / cable produced using a compound containing the above-mentioned polyolefin resin composition.

One group of the polyolefin resin compositions of the present invention, in which the appearance of molded articles obtained by using the same is particularly improved, is 30 to 70 parts by weight of a polyolefin having a crystalline melting point of 150 ° C. or more. And soft polymer 30 ~
In the polyolefin resin composition obtained by blending 70 parts by weight, an organic peroxide and 0.1 to 5 parts by weight of maleic anhydride with respect to 100 parts by weight of the composition as essential components, the soft polymer is a polyolefin , A copolymer of an olefin and another polymerizable monomer, or one or more polymers selected from the group consisting of derivatives thereof, and the composition has a value of 1 according to a calorimetric measurement by DSC.
A polyolefin resin composition having a plurality of crystal melting peaks in a region of 50 ° C. or higher.

A group of electric wires and cables according to the present invention, in which the appearance is particularly improved, is an electric wire having an insulator or a jacket constituted by using a compound containing the above-mentioned polyolefin resin composition.・ It is a cable.

The polyolefin having a crystalline melting point of 150 ° C. or more in the present invention includes polypropylene, ethylene copolymerized polypropylene, poly-4-methyl-pentene-1 and the like.

The soft polymer in the present invention may be a soft polyolefin such as a soft olefin homopolymer or an olefin copolymer (binary copolymer or terpolymer), or a copolymer of an olefin and another polymerizable monomer. Including coalesced copolymers (binary copolymers and ternary copolymers) and derivatives thereof, the olefin may be substituted by a substituent.

The above-mentioned soft olefin homopolymer includes:
Low-density polyethylene, linear low-density polyethylene, and homopolymers of α-olefins such as polybutene-1 are exemplified.

The olefin copolymers include ethylene-propylene copolymer, ethylene-octene-1 copolymer, ethylene-butene-1 copolymer, and ethylene-butene-hexene terpolymer. A copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, or ethylene-
Terpolymers of ethylene, α-olefin having 3 to 10 carbon atoms and diene such as propylene-diene terpolymer, styrene-ethylene-butylene terpolymer, styrene-ethylene-bin copolymer Coalescence, styrene-ethylene-
Examples include a propylene terpolymer, a styrene-propylene binary copolymer, and the like.

Examples of the copolymer of the olefin and other polymerizable monomers include ethylene and methacrylic acid ester such as ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer and ethylene-ethyl acrylate copolymer. Copolymers with acrylic esters, or ethylene-glycidyl methacrylate copolymer, ethylene-maleic anhydride copolymer, ethylene-vinyl acetate copolymer, and the like, further as a polymer obtained from a substituted olefin as Styrene-butadiene copolymer, hydrogenated styrene-butadiene copolymer, and the like.

Examples of the derivative include chlorinated polyethylene and chlorosulfonated polyethylene alone or a plastic material in which two or more kinds are blended.

Examples of the organic peroxide in the present invention include radical initiators such as hydroperoxides, dialkyl peroxides, and diacyl peroxides. In the following examples, dicumyl peroxide is used.

The polyolefin resin composition of the present invention may contain additives such as a flame retardant, an antioxidant, a lubricant, a surfactant, a colorant, a softener, a plasticizer, an inorganic filler, and a compatibilizer, if necessary. Can be added.

The flame retardant is added to improve the flame retardancy of the polyolefin resin composition. Examples of such a flame retardant include phosphorus compounds, hydrated metal compounds, metal oxide compounds, and bromine-based flame retardants. Can be mentioned. These flame retardants can be used alone or in combination of two or more. Examples of the phosphorus compound include red phosphorus, phosphate ester, phosphate, and phosphorinene. Examples of the hydrated metal compound include magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, calcium hydroxide, barium hydroxide, and hard clay. Examples of the metal oxide compound include antimony oxide, aluminum oxide, and magnesium oxide. Chlorinated paraffin and the like can be mentioned as the chlorine-based flame retardant. Examples of brominated flame retardants include ethylene tetrabromide and ethylene-bispentabromobenzene. Also,
It is also possible to add a fatty acid, a fatty acid metal salt or the like according to a conventional method, or to treat with a silane-based or titanate-based coupling agent.

In the present invention, maleic anhydride functions as a reactive monomer and improves the appearance of molded articles such as electric wires and cables obtained from the polyolefin resin composition. Reactive monomers that can be used in combination with maleic anhydride for such purposes include glycidyl methacrylate and vinyl silane compounds. Examples of the vinylsilane compound include ethylenically unsaturated silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropylvinyltrimethoxysilane, and vinyltris (2-methoxyethoxy) silane. I can do it.

In the present invention, maleic anhydride and other polymer components constituting the polyolefin resin composition undergo a denaturation reaction by heating and kneading at the time of compounding. In this case, the unsaturated dihydration of α-aromatic-α-methylalkene is carried out. When a monomer or a mercapto compound or a salt thereof is added, these act as a chain transfer agent, and can cause a reactive monomer such as maleic anhydride to react uniformly.

[0022]

EXAMPLES Hereinafter, specific examples and comparative examples of the present invention will be described in detail.

[0023]

[Table 1]

Examples 1 to 6 of Table 1 and 10 of Comparative Examples 1 to 4
Compounds were prepared according to the types of blends, and DSC measurements (see FIG. 1) of the obtained compounds, cables were prepared from the obtained compounds, and heat resistance tests, low-temperature bending tests, and appearance tests were performed.

The compound is prepared by dry blending predetermined components and then using a 90 mm twin screw extruder.
The mixture was kneaded at 0 ° C. to obtain a compound.

The DSC measurement of the compound was performed as follows. The temperature was raised up to 250 ° C. at a rate of temperature rise of 10 ° C./min. A melting peak corresponding to a crystal having a smaller size occurring on a lower temperature side than a crystal melting peak of a base polyolefin is not observed at all, or even if observed, 1
What was less than 50 ° C. was marked with a cross. Also, 150
A single circle mark indicates a plurality of crystal melting peaks at or above ° C.

FIG. 1 is a DSC curve diagram. The data for polypropylene (bottom) and the composition of Example 1 (top) are shown.

The cable was manufactured as follows. 4. An outer diameter of 2.5 insulated two strands of 1.7 mm in diameter insulated wire made of a copper stranded wire conductor of 3.5 mm in diameter covered with crosslinked polyethylene, and a pair of stranded wires formed by solid extrusion of the compound.
A 0 mm cable was made.

In the low-temperature bending test, the obtained cable was subjected to a load of 2 kg at -30.degree.
Five cycles of a 90-degree left-right bending test were performed. The curvature radius at the time of bending was 10 mm. FIG. 2 shows an outline of the tester. A cable having a number of bending times of 20,000 or less until the conductor of the cable is broken was marked with a cross. (See Fig. 2.) The heat resistance test was performed by wrapping a cable around a metal rod having a diameter of 5 mm at 150 ° C.
For 10 days. Thereafter, the winding was released, and the heat resistance was determined based on the presence or absence of welding between the cable jackets.
The spot where welding was observed was marked as a cross.

In the appearance test, the appearance of the cable was visually observed. Those with rough appearance were marked with a cross, those with good appearance were marked with a single circle, and those with excellent appearance were marked with a double circle.

As is evident from Table 1, the compounds of Examples 1 to 6 according to the present invention and the cables prepared therefrom all had good heat resistance, low-temperature bending characteristics and good cable appearance. On the other hand, in the case of Comparative Examples 1 to 4, any one of heat resistance, low-temperature bending characteristics, and cable appearance was rejected.

In Examples 1-3 and 6, polypropylene was used as the polyolefin having a crystalline melting point of 150 ° C. or higher, and ethylene-octene-1 copolymer was used as the soft polymer.

As the polyolefin having a crystal melting point of 150 ° C. or higher in Example 4, polypropylene was
Ethylene-propylene copolymer rubber was used as the soft polymer.

In Example 5, poly-4-methylpentene-1 was used as the polyolefin having a crystal melting point of 150 ° C. or more, and ethylene-octene-1 copolymer and ethylene-vinyl acetate copolymer were used as the soft polymers. Were used.

[0035]

As described above, in short, according to the present invention, heat resistance,
Polyolefin compositions with good low-temperature bending characteristics and appearance of molded products, and wires and cables with good heat resistance, low-temperature bending characteristics, and good appearance in which the insulator or jacket is composed of a compound containing this composition as a main component. Can be provided.

[Brief description of the drawings]

FIG. 1 is a DSC curve diagram. FIG. 2 is a graph showing a relationship between an endothermic amount (arbitrary unit) and a temperature (° C.) for polypropylene (bottom) and the composition of Example 1 (top).

FIG. 2 is a schematic view of a bending tester.

FIG. 3 is a schematic view of one embodiment of a cable to which the polyolefin resin composition of the present invention is applied.

FIG. 4 is a schematic view of another embodiment of a cable to which the polyolefin resin composition of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper conductor 2 Insulator 3 Intervention 4 Holding tape 5 Jacket 11 Sample cable 12 Bending jig 13 Sample cable fixture 14 Weight

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01B 9/00 H01B 9/00 A // C08L 23/26 C08L 23/26

Claims (4)

[Claims] 1. 30 to 70 parts by weight of a polyolefin having a crystalline melting point of 150 ° C. or higher, and 30 to 70 parts of a soft polymer.
Parts by weight, and a polyolefin resin composition obtained by blending an organic peroxide as an essential component, wherein the soft polymer is a polyolefin, a copolymer of an olefin and another polymerizable monomer, or a derivative thereof. A polyolefin resin composition comprising one or more selected polymers, and wherein the composition has a plurality of crystal melting peaks in a region of 150 ° C. or higher in a calorimetric measurement by DSC. 2. 30 to 70 parts by weight of a polyolefin having a crystalline melting point of 150 ° C. or more, and 30 to 70 parts of a soft polymer.
Parts by weight, and a polyolefin resin composition obtained by blending, as an essential component, 0.1 to 5 parts by weight of maleic anhydride with respect to 100 parts by weight of the organic peroxide and the composition,
The soft polymer comprises one or two or more polymers selected from the group consisting of polyolefins, copolymers of olefins and other polymerizable monomers, and derivatives thereof;
And the composition has a calorimetric value of 150
A polyolefin resin composition having a plurality of crystal melting peaks in a region of not less than ° C. 3. 30 to 70 parts by weight of a polyolefin having a crystalline melting point of 150 ° C. or more, and 30 to 70 parts of a soft polymer.
Parts by weight, and a polyolefin resin composition obtained by blending an organic peroxide as an essential component, wherein the soft polymer is a polyolefin, a copolymer of an olefin and another polymerizable monomer, or a derivative thereof. An electric wire or a wire made of a polyolefin resin composition comprising one or more selected polymers and having a plurality of crystal melting peaks in a region of 150 ° C. or more in a calorimetric measurement by DSC. cable. 4. 30 to 70 parts by weight of a polyolefin having a crystalline melting point of 150 ° C. or more, and 30 to 70 parts of a soft polymer.
Parts by weight, and a polyolefin resin composition obtained by blending, as an essential component, 0.1 to 5 parts by weight of maleic anhydride with respect to 100 parts by weight of the organic peroxide and the composition,
The soft polymer comprises one or more polymers selected from the group consisting of polyolefins, copolymers of olefins and other polymerizable monomers, and derivatives thereof;
And the composition has a calorimetric value of 150
An electric wire or cable having an insulator or a jacket constituted by using a compound containing a polyolefin resin composition having a plurality of crystal melting peaks in a region of not less than ° C.