JP2011149026A - Resin composition and insulated electric wire coated with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition excellent in flame retardance, mold processability, mechanical characteristics, heat resistance and cold resistance and giving no elution of heavy metal compounds, no generation of a large amount of smoke, and corrosive gases in disposing such as reclamation, burning and the like, and to provide an insulated electric wire coated with the resin composition. <P>SOLUTION: The resin composition is obtained by compounding 60-180 pts.mass of (e) an inorganic hydrate based on 100 pts.mass of a resin mixture which includes: 20-60 mass% of (a) flexible polypropylene obtained by a multistage polymerization method consisting of a polymerization process which includes: homopolymerization of propylene of a first step or a random copolymerization step of propylene and ethylene; and the following copolymerization step of ethylene and one or more kinds of α-olefins of three or more carbon numbers and/or (b) an ethylene-vinyl acetate copolymer in which the vinyl acetate content is at least 30 mass%; (c) 0-20 mass% of modified polyethylene; and (d) 40-80 mass% of modified polypropylene. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin composition and an insulated wire used for automobiles, electrical / electronic devices and the like, and more specifically, does not generate a large amount of smoke or harmful gas during incineration, and is flame retardant and cold resistant. The present invention relates to a resin composition and an insulated wire excellent in heat resistance, mechanical properties, and moldability.

Various properties such as flame retardancy and mechanical properties are required for members and insulated wires used in automobiles, electrical / electronic devices, etc., and the materials include polyvinyl chloride (PVC) compounds and molecules. Polyolefin compounds containing a halogen-based flame retardant containing bromine and chlorine atoms were mainly used.
In recent years, various problems that occur when products using such materials are discarded without appropriate treatment have been discussed. For example, when landfilled, plasticizers and heavy metal stabilizers mixed in the material will be eluted. It is happening.

For this reason, non-halogen flame retardant compositions that do not generate harmful heavy metals or corrosive halogen-based gases have been proposed, and some have been put into practical use.
Non-halogen flame retardant compositions that have been proposed and put to practical use generally use polyolefin-based resins that are highly filled with inorganic hydrates. In order to impart, it is necessary to blend a large amount of inorganic hydrate, and as the base polymer, an ethylene-based copolymer that is easy to blend with inorganic hydrate is mainly used.
However, it is a problem that the mechanical properties, heat resistance, etc. of such non-halogen flame retardant compositions are low compared to the properties of currently used PVC compounds, and non-halogen flame retardant compositions having properties comparable to PVC compounds. The development of things is awaited.

In order to solve such problems, a method of cross-linking a non-halogen flame retardant composition having an ethylene-based copolymer as a base polymer by chemical cross-linking or electron beam cross-linking means (see, for example, Patent Document 1), mechanical properties and heat resistance A method of using polypropylene having excellent properties as a base polymer (for example, see Patent Document 2) has been studied, but a resin composition balanced in flame retardancy, mechanical properties, heat resistance, cold resistance, etc. The current situation is that it has not been obtained.
Japanese Patent Laid-Open No. 11-213769 JP 2000-248126 A

  The present invention is a resin composition made by paying attention to the above circumstances, and particularly when employed in members and insulated wires used in automobiles, robots, electrical / electronic devices, etc., moldability, flame retardancy, Resin composition excellent in mechanical properties, heat resistance and cold resistance, and free from elution of heavy metal compounds, generation of large amounts of smoke and corrosive gas at the time of disposal such as landfill and incineration, and its production method and The object is to provide a coated insulated wire.

As a result of intensive studies to achieve the above object, the present inventors have found that a specific resin composition is suitable for the purpose, and have made the present invention.
That is, the present invention
(1) (a) Polymerization including propylene homopolymerization in the first stage or random copolymerization stage of propylene and ethylene, and copolymerization stage of the next ethylene and one or more kinds of α-olefin having 3 or more carbon atoms Soft polypropylene and / or (b) ethylene / vinyl acetate copolymer having a vinyl acetate content of 30% by mass or more, (c) 0 to 20 mass of modified polyethylene obtained by a multistage polymerization method comprising steps %, (D) a resin composition comprising (e) 60 to 180 parts by mass of an inorganic hydrate with respect to 100 parts by mass of a resin mixture containing 40 to 80% by mass of a modified polypropylene, and (2) (1) Provided is an insulated wire characterized by covering a conductor with the resin composition.

Since the resin composition of the present invention and the insulated wire covering the resin composition are non-halogen compositions containing polypropylene as a main component of resin, elution of heavy metal compounds, large amounts of smoke and harmful gases are generated during disposal and incineration. There is nothing.
In addition, the resin mixture consisting of soft polypropylene and / or ethylene / vinyl acetate copolymer, modified polyethylene, and modified polypropylene is blended with inorganic hydrates. It is possible to provide a member and an insulated wire that are well balanced in properties and mechanical properties.
Furthermore, in the method for producing a resin composition of the present invention, a homogeneous composition can be produced as a whole.

  The preferred embodiment of the resin composition of the present invention will be described in detail. First, each component constituting the composition and its composition ratio will be described.

(A) Soft polypropylene The soft polypropylene of the resin composition of the present invention is preferably obtained by a multistage polymerization method. The multistage polymerization method includes the first stage of homopolymerization of propylene or the random stage of copolymerization of propylene and a small amount of ethylene, and the stage of copolymerization of the next ethylene with one or more α-olefins having 3 or more carbon atoms. Comprising a polymerization step. By this polymerization method, the resin component produced in each stage is as if it was blended in the reactor at the time of polymerization, so the amorphous component is dispersed very finely, and flexibility, filler acceptance Polypropylene having excellent properties can be obtained. This polymerization method is disclosed, for example, in JP-A-6-25367.
Examples of such soft polypropylene include commercially available “Adflex” (trade name, manufactured by SumAllomer), “HiFax” (trade name, manufactured by Basell), and the like.

(B) Ethylene / vinyl acetate copolymer The ethylene / vinyl acetate copolymer of the resin composition of the present invention has a vinyl acetate content of 30% by mass or more, further 40% by mass from the viewpoint of filler acceptability. The above is preferable.
Examples of such a material include “Evaflex” (trade name, manufactured by Mitsui DuPont Polychemical) and “Levapren” (trade name, manufactured by Bayer).
The proportion of (a) soft polypropylene and / or (b) ethylene / vinyl acetate copolymer in the resin composition is based on the total amount of resin components, that is, soft polypropylene, ethylene / vinyl acetate copolymer, modified polypropylene, and the like. It is 20-60 mass% of the total amount of the resin mixture which becomes, Preferably it is 30-50 mass%.
When this ratio is small, the flame retardancy of the resin composition decreases, and when it is large, the mechanical properties and heat resistance of the resin composition decrease, which is not preferable.

(C) Modified polyethylene The modified polyethylene in the composition of the present invention is obtained by modifying polyethylene with an unsaturated carboxylic acid or a derivative thereof. Here, the modification is obtained by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof with polyethylene.
As the polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene and the like are used.
Examples of the unsaturated carboxylic acid for modification include maleic acid, itaconic acid, and fumaric acid. Examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, and itaconic acid monoester. Itaconic acid diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester, and the like are used.

Examples of such modified polyethylene include “Adtex” (trade name, manufactured by Nippon Polyolefin Co., Ltd.), “OREVAC” (trade name, manufactured by ATOFINA), and the like.
The modified polyethylene component (c) is used for the purpose of improving the compatibility between the modified polypropylene component (d) and the component (b), particularly when the ethylene / vinyl acetate component (b) is used. Therefore, the modified polyethylene component (c) may or may not be blended regardless of whether the ethylene / vinyl acetate component (b) is used.
The proportion of (c) modified polyethylene in the resin composition is 0 to 20 mass of the total amount of the resin component, that is, the total amount of the resin mixture composed of soft polypropylene, ethylene / vinyl acetate copolymer, modified polyethylene, modified polypropylene and the like. %, Preferably 0 to 10% by mass. If the blending ratio is too large, the mechanical properties and heat resistance of the resin composition are lowered, which is not preferable.

(D) Modified polypropylene The modified polypropylene in the composition of the present invention is obtained by modifying polypropylene with an unsaturated carboxylic acid or a derivative thereof. Here, the modification is obtained by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof with polypropylene.
The polypropylene used for modification is preferably a propylene homopolymer, an ethylene / propylene block copolymer, an ethylene / propylene random copolymer, or a soft polypropylene.
Examples of the unsaturated carboxylic acid include maleic acid, itaconic acid, and fumaric acid. Examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, and itaconic acid. Diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester, and the like are used.

Examples of such modified polypropylene include “Adtex” (trade name, manufactured by Nippon Polyolefin Co., Ltd.), “OREVAC” (trade name, manufactured by ATOFINA), “POLYBOND” (trade name, manufactured by UNIROYAL), and the like. it can.
The proportion of the (d) modified polypropylene in the resin composition is 40 to 80% by mass, preferably 50 to 70% by mass, based on the total amount of the resin mixture.
When the blending ratio is small, the mechanical properties and heat resistance of the resin composition are lowered, and when it is large, the flame retardancy of the resin composition is lowered, which is not preferable.

(E) Inorganic hydrate In the composition of the present invention, the inorganic hydrate blended in the resin composition is not particularly limited, but aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydration Compounds having a hydroxyl group or water of crystallization such as magnesium silicate, basic magnesium carbonate, hydrotalcite and the like can be mentioned, and these can be used alone or in combination of two or more.
As the inorganic hydrate of the present invention, those subjected to a surface treatment with a surface treatment agent such as a silane compound (silane coupling agent), a fatty acid, and a phosphate ester can be used. Of course, unprocessed ones may be used.

As these inorganic hydrates, aluminum hydroxide and magnesium hydroxide are preferable. Examples of such inorganic hydrates include “Hijilite” (trade name, manufactured by Showa Denko KK), “Kisuma” (trade name, Kyowa). (Commercially available from Chemical Co., Ltd.).
The proportion of the (e) inorganic hydrate in the resin composition is 60 to 180 parts by weight, preferably 80 to 180 parts by weight, more preferably 100 to 160 parts by weight with respect to 100 parts by weight of the resin mixture. It is.
When this ratio is small, sufficient flame retardancy cannot be imparted to the resin composition, and when it is too large, the mechanical properties and cold resistance of the resin composition are lowered, which is not preferable.

Next, the manufacturing method of the resin composition of this invention and an insulated wire is demonstrated.
About the manufacturing method of a resin composition, although manufacturing by the following processes is preferable, for example, it is not limited to these.
First, the inorganic hydrate component (e) is melt-kneaded into at least a part of the soft polypropylene component (a), the ethylene / vinyl acetate copolymer component (b) and the modified polyethylene component (c), and the resin composition (f ). Next, the resin composition (f) is melt-kneaded with the component (a), the component (b), the remainder of the component (c) and the modified polypropylene component (d) to produce the resin composition of the present invention.
According to this method, mixing between resins and inorganic hydrate can be easily and uniformly achieved, and the physical properties of the composition are uniform throughout.

The kneading apparatus is not particularly limited, but a commonly used kneading apparatus such as a twin screw extruder, a Banbury mixer, a kneader, or a roll can be used.
Furthermore, the resin composition of the present invention includes various resins and rubbers generally used in resin compositions, and additives (antioxidants, metal deactivators, ultraviolet absorbers, dispersants, A crosslinking agent, a crosslinking aid, a pigment, and the like) can be appropriately blended as necessary within a range not impairing the object of the present invention.

Since the resin composition of the present invention is excellent in moldability and the like, for example, as an insulating material such as a connector, a plug, a relay, etc. as an electrical / electronic equipment component, a connector of an automobile, a robot, a switch, etc. There are wide applications.
Moreover, the insulated wire of this invention can be manufactured by extrusion-coating the said resin composition around a conductor using the normal extruder for electric wire manufacture.
The insulated wire of the present invention can be crosslinked if necessary. The crosslinking method is not particularly limited, and can be carried out by chemical crosslinking method or electron beam crosslinking method.
The conductor diameter, the conductor material, and the like of the insulated wire of the present invention are not particularly limited and can be appropriately determined according to the application.
The thickness of the insulator is not particularly limited, and may be about 0.2 to 2 mm as in the normal case. Further, the insulator may have a multilayer structure, such as providing an intermediate layer between the insulator and the conductor.

EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these.
(Examples 1-7, Comparative Examples 1-5)
The soft polypropylene component (a), the ethylene / vinyl acetate copolymer component (b), the modified polyethylene component (c), and polypropylene were melted in about 2/3 of the amount shown in Tables 1 and 2 and hydroxylated. Add the indicated amount of magnesium and melt knead with a kneader. Next, the acid-modified polypropylene component (d) in the amount shown in the table, the remaining component (a), component (b), component (c), polypropylene, antioxidant, and lubricant were added and further melt-kneaded. A resin composition was obtained.
Table 1 shows the component blending amounts (shown in parts by mass) and physical properties of the resin compositions of each Example, and Table 2 shows the component blending amounts (shown in parts by mass) and physical properties of the resin compositions of each Comparative Example. Show.

As each component shown in Table 1 and Table 2, the following were used.
(01) Soft polypropylene HiFax 7320XP (trade name, manufactured by Basell)
(02) Ethylene / vinyl acetate copolymer EVAFLEX EV180 (trade name, manufactured by Mitsui / DuPont Polychemicals)
(03) Modified polyethylene Adtex (trade name, manufactured by Nippon Polyolefin)
(04) Acid-modified polypropylene Adtex ER313E-1 (trade name, manufactured by Nippon Polyolefin)
(05) Polypropylene PL500A (trade name, manufactured by Sun Allomer)
(06) Magnesium hydroxide Kisuma 5J (trade name, manufactured by Kyowa Chemical Co., Ltd.)
(07) Antioxidant Irganox 1010 (trade name, manufactured by Ciba Specialty Chemicals)
(08) Lubricant Calcium stearate (manufactured by NOF Corporation)

The press sheet of the resin composition obtained by each Example and the comparative example was created, the following measurement was performed about those characteristics, and the following evaluation was carried out. The results are shown in Table 1 and Table 2 as sheet physical properties.
(1) Heat resistance (heat deformation)
A press sheet having a thickness of 2 mm was prepared, and the deformation rate was measured at a test temperature of 160 ° C. and a test load of 1 kgf (9.8 N) in accordance with JIS K6720. The thing was set as x.
(2) Cold resistance (brittleness)
A press sheet having a thickness of 2 mm was prepared, and the minimum temperature at which the number of fractures / number of tests was 0/5 was examined at 10 ° C. intervals in accordance with JIS K7216.
(3) Flame retardance A 3 mm thick press sheet was prepared, and in accordance with UL94HB, the flame extinguished before reaching the 100 mm mark on the sample was regarded as self-extinguishing. .

Furthermore, the resin composition obtained in each Example and Comparative Example was extrusion-coated with a thickness of 0.2 mm on a 0.8 mmφ annealed copper wire with a general-purpose extruder for producing an electric wire to produce an insulated wire. About the characteristic of each obtained electric wire, the following test was implemented and the following evaluation was performed. The results are shown in Tables 1 and 2 as wire properties.
(4) Tensile properties Tensile strength (TS) (MPA) and elongation (El.) (%) Of the insulator of the obtained insulated wire were measured at a marked line of 50 mm and a tensile speed of 50 mm / min.
(5) Abrasion resistance Abrasion resistance was measured by a blade reciprocation method specified in JASO D611.
With a load of 500 gf (4.9 N), the number of wears was measured.
(6) Flame retardance A horizontal combustion test specified in JIS C3005 was conducted, and the flame extinguished within 15 seconds was accepted and the one burned for 15 seconds or more was rejected.

As shown in the results of Table 2, Comparative Examples 1 to 3 and 5 which are outside the scope of the present invention are inferior in cold resistance, wear resistance and tensile strength, and Comparative Example 4 having a small amount of inorganic hydrate is There is a problem with flame retardancy. Further, Comparative Example 2 has difficulty in elongation, and Comparative Example 3 has difficulty in heat resistance.
In contrast, as shown in Table 1, the resin compositions and insulated wires shown in the examples of the present invention are balanced in heat resistance, cold resistance, flame resistance, and mechanical properties. is there.

Claims (2)

  (A) It consists of a polymerization process including a homopolymerization of propylene in the first stage or a random copolymerization stage of propylene and ethylene, and a copolymerization stage of the next ethylene and one or more kinds of α-olefin having 3 or more carbon atoms. Soft polypropylene obtained by a multistage polymerization method and / or (b) ethylene / vinyl acetate copolymer having a vinyl acetate content of 30% by mass or more, 20 to 60% by mass, (c) 0 to 20% by mass of modified polyethylene, ( d) A resin composition comprising (e) 60 to 180 parts by mass of an inorganic hydrate with respect to 100 parts by mass of a resin mixture containing 40 to 80% by mass of modified polypropylene.   An insulated wire comprising a conductor coated with the resin composition according to claim 1.