Abstract:
The present invention relates to a resin composition comprising: (a) 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least 0.930; (b1) 5 to 65 parts by mass of olefin type polymer containing intra molecular oxygen atoms; (c) 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of (c1) acid modified olefin polymers containing intra-molecular oxygen atoms, (c2) acid modified styrene type thermoplastic elastomers, (c3) acid-modified polyethylenes having a density of about 0.920 at the most, and (c4) acid modified rubbers, with the proviso that the total of components (a), (b1) and (c) represents 100 parts by mass; and (d) 30 to 250 parts by mass of metal hydroxide. This abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a wear resistant, flame-retardant material composition and to an electric cable or wire covered with a material containing such a composition. This type of protected electric cable or wire is used, for example, in automotive vehicles.  
           [0003]    2. Description of Background Information  
           [0004]    Polyvinyl chloride has been widely used as a coating material for electrical cables or wires used in vehicles, owing to its excellent mechanical strength, facility with which it can be extruded around an electric cable, its excellent flexibility and paintability, as well as its low cost.  
           [0005]    However, because of recent environmental measures, manufacturing of parts for vehicles, including coatings of electrical wires used in vehicles, has started to use halogen free (polymer) materials instead of polyvinyl chloride.  
           [0006]    A halogen free resin composition containing a polyolefin as a base polymer and metal hydroxides as flame retardants is well known (see JP-A-7-176219 and JP-A-7-78518). This composition is a wear resistant resin composition and has the advantage of not producing toxic gas such as halogen gas when burning.  
           [0007]    However, it is necessary to add large amounts of metal hydroxides to make this composition sufficiently flame retardant to yield a self extinguishing property. When adding such large amounts of metal hydroxides, the mechanical strength of the composition, such as its wear resistance and tensile strength falls dramatically. To prevent such lowering of mechanical strength, it has been suggested to raise the amount of propylene having a relatively high hardness and the amount of polypropylene having a high density. However, in this case, the flexibility of the protected electric cable or wire is then lowered and the manufacturability thereof is also lowered.  
           [0008]    JP-A-6-290638 discloses a resin composition containing metal hydroxides used for insulating electrical wires. This composition contains polypropylene as the main component (more than 80%). The other components of this composition are copolymers of styrene and polyethylene modified by acid anhydrides.  
           [0009]    U.S. Pat. No. 5,561,185 discloses as a resin composition containing metal hydroxides, used for protecting electrical wires, a resin composition containing:  
           [0010]    (a) 40 to 88.5% by mass (or by weight) of a polypropylene type resin containing at least 50% by mass of ethylene-propylene random copolymers;  
           [0011]    (b) 1.5 to 30% by mass of polyethylene modified by an unsaturated carboxylic acid or derivatives thereof (e.g. maleic anhydride); and  
           [0012]    (c) 10 to 48% by mass of ethylene type copolymer, typically ethylene/vinyl acetate copolymer.  
           [0013]    U.S. Pat. No. 5,180,889 discloses a resin composition containing metal hydroxides as a coating for the conductor of a crush resistant cable. This composition contains:  
           [0014]    a) ethylene/α olefin copolymer having a low density;  
           [0015]    b) a system of styrene-ethylene-butylenes-styrene tri-block copolymer-elastomer, preferably modified by maleic anhydride; and  
           [0016]    c) optionally, a shock-resistant propylene copolymer or polypropylene.  
           [0017]    It has been proposed to improve the heat resistance of the resin composition used for electrical wire insulation by cross-linking the resin composition.  
           [0018]    JP-A-8-161942 proposes to coat electrical wires with a resin composition containing an ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate (EEA) and metal hydrates, and to cross-link this composition using electron beam irradiation.  
           [0019]    JP-A-2000-294039 proposes to cross-link a composition containing ethylene type polymer(s) and maleic anhydride modified polyolefins.  
           [0020]    The compositions obtained by cross-linking a resin composition containing as a base an ethylene type polymer have excellent heat resistance but insufficient wear resistance.  
           [0021]    JP-A-2000-86830 discloses a composition obtained by cross-linking a resin composition containing polyolefin type elastomers, metal hydroxides and a coupling-agent surface treated potassium titanate.  
           [0022]    JP-A-2000-336215 discloses a resin composition containing a polyolefin type resin prepared with magnesium hydroxide or aluminum hydroxide whose surface is treated, silicone powder and a cross-linking accelerator. This composition is also cross-linked.  
           [0023]    Such compositions have an improved tensile and mechanical strength, but a poor flexibility and formability.  
         SUMMARY OF THE INVENTION  
         [0024]    One purpose of the present invention is to provide a flame retardant resin composition containing metal hydroxides which is suitable for coating electrical wires or cables, and which has an improved flame retardant quality, as well as improved wear resistance, flexibility and formability.  
           [0025]    To solve the above-mentioned problem, there is provided a resin composition comprising:  
           [0026]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0027]    (b1) about 5 to 65 parts by mass of olefin type polymer containing intra molecular oxygen atoms;  
           [0028]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0029]    (c1) acid modified olefin polymers containing intra-molecular oxygen atoms;  
           [0030]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0031]    (c3) acid-modified polyethylenes having a density of about 0.920 at the most; and  
           [0032]    (c4) acid modified rubbers,  
           [0033]    with the proviso that the total of components (a), (b1) and (c) represents 100 parts by mass; and  
           [0034]    (d) about 30 to 250 parts by mass of metal hydroxide.  
           [0035]    Preferably, the resin composition is cross-linked by electron beam irradiation.  
           [0036]    Alternatively, the invention relates to a resin composition comprising:  
           [0037]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0038]    (b2) about 5 to 65 parts by mass of styrene type thermoplastic elastomer; and  
           [0039]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0040]    (c1) acid modified olefin type polymers containing intra-molecular oxygen atoms, and  
           [0041]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0042]    with the proviso that the total of components (a), (b2) and (c) represents 100 parts by mass; and  
           [0043]    (d) about 30 to 250 parts by mass of metal hydroxide.  
           [0044]    Preferably, the resin composition is cross-linked by electron beam irradiation.  
           [0045]    The invention further relates to a process for applying, to a conductor element, a resin composition comprising:  
           [0046]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0047]    (b1) about 5 to 65 parts by mass of olefin type polymer containing intra molecular oxygen atoms;  
           [0048]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0049]    (c1) acid modified olefin polymers containing intra-molecular oxygen atoms;  
           [0050]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0051]    (c3) acid-modified polyethylenes having a density of about 0.920 at the most; and  
           [0052]    (c4) acid modified rubbers,  
           [0053]    with the proviso that the total of components (a), (b1) and (c) represents 100 parts by mass; and  
           [0054]    (d) about 30 to 250 parts by mass of metal hydroxide;  
           [0055]    so as to prepare an electrical cable.  
           [0056]    Preferably, the above process further comprises the step of irradiating the resin composition with electron beams.  
           [0057]    Alternatively, the invention concerns a process for applying, to a conductor element, a resin composition comprising:  
           [0058]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0059]    (b2) about 5 to 65 parts by mass of styrene type thermoplastic elastomer; and  
           [0060]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0061]    (c1) acid modified olefin type polymers containing intra-molecular oxygen atoms, and  
           [0062]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0063]    with the proviso that the total of components (a), (b2) and (c) represents 100 parts by mass; and  
           [0064]    (d) about 30 to 250 parts by mass of metal hydroxide;  
           [0065]    so as to prepare an electrical cable.  
           [0066]    Preferably, the above process further comprises the step of irradiating the resin composition with electron beams.  
           [0067]    There is further provided an electrical cable coated with a resin composition comprising:  
           [0068]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0069]    (b1) about 5 to 65 parts by mass of olefin type polymer containing intra molecular oxygen atoms;  
           [0070]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0071]    (c1) acid modified olefin polymers containing intra-molecular oxygen atoms;  
           [0072]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0073]    (c3) acid-modified polyethylenes having a density of about 0.920 at the most; and  
           [0074]    (c4) acid modified rubbers,  
           [0075]    with the proviso that the total of components (a), (b1) and (c) represents 100 parts by mass; and  
           [0076]    (d) about 30 to 250 parts by mass of metal hydroxide.  
           [0077]    Suitably, the resin composition is further cross-linked by electron beam irradiation.  
           [0078]    There is further provided an electrical cable coated with a resin composition comprising:  
           [0079]    (a) about 30 to 90 parts by mass of polyethylene having a melt flow rate (MFR) of about 5 g/10 min at the most and a density of at least about 0.930;  
           [0080]    (b2) about 5 to 65 parts by mass of styrene type thermoplastic elastomer; and  
           [0081]    (c) about 5 to 40 parts by mass of at least one type of polymer selected from the group consisting of:  
           [0082]    (c1) acid modified olefin type polymers containing intra-molecular oxygen atoms and  
           [0083]    (c2) acid modified styrene type thermoplastic elastomers;  
           [0084]    with the proviso that the total of components (a), (b2) and (c) represents 100 parts by mass; and  
           [0085]    (d) about 30 to 250 parts by mass of metal hydroxide.  
           [0086]    Suitably, the resin composition is further cross-linked by electron beam irradiation.  
         DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
         [0087]    Each component of the composition of the invention is chosen in order to confer, when mixed with the others, a desired property to the resulting material. Explanations regarding each of the components are given hereinafter.  
           [0088]    Component (a) is a polyethylene having a melt flow rate (MFR) of 5 g/10 min or less and a density of at least 0.930.  
           [0089]    The polyethylene used can be any polyethylene having the above-mentioned density and melt flow rate. However, high density polyethylene or straight-chain low density polyethylene are preferably used.  
           [0090]    When the MFR of polyethylene exceeds 5 g/10 min, the formability of the composition is deteriorated.  
           [0091]    The MFR value is measured according to JIS K 6921-2.  
           [0092]    Moreover, when the density of the polyethylene is less than 0.930, the hardness of the composition is lowered, and its wear resistance is also lowered.  
           [0093]    The amount of component (a) represents 30 to 90 parts by mass, preferably 30 to 80 parts by mass, in the total of 100 parts by mass consisting of component (a), component (b1) or (b2) and component (c).  
           [0094]    When the amount of component (a) is higher than the upper limit, the flexibility and formability of the composition are lowered. When this amount is lower than the lower limit, the composition has a poor wear resistance.  
           [0095]    Examples of olefin polymers (b1) containing intramolecular oxygen atoms include a copolymer of olefins (e.g. ethylene) and unsaturated monomers containing oxygen atoms (e.g. vinyl acetate, ethyl acrylate and ethyl methacrylate). In practice, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers and ethylene-methyl methacrylate copolymers can be given as examples.  
           [0096]    The styrene type thermoplastic elastomers (b2) may be, for example, thermoplastic copolymers of styrene and olefins (e.g. ethylene or propylene). Practically, styrene-ethylene block copolymers, styrene-ethylene-propylene block copolymers and their hydrogenated derivatives obtained by adding hydrogen atoms in their unsaturated bonds can be given as examples.  
           [0097]    The amount of component (b1) or (b2) ranges from 5 to 65 parts by mass, preferably from 10 to 60 parts by mass, in the total of 100 parts by mass consisting of component (a), component (b1) or (b2) and component (c).  
           [0098]    When the amount of component (b1) or (b2) is higher than the above-mentioned upper limit, the wear resistance of the composition is lowered. When this amount is lower than the above-mentioned lower limit, the flexibility and formability of the composition are lowered.  
           [0099]    Examples of acid-modified olefin polymers (c1) containing intramolecular oxygen atoms include polymers which may be obtained by introducing, as acid components, unsaturated carboxylic acids or their derivatives (e.g. anhydrides or esters) into olefin polymers (b1) containing intramolecular oxygen atoms. Typical examples of such unsaturated carboxylic acids or their derivatives include maleic acid, fumaric acid, maleic anhydride, maleic acid monoesters and maleic acid diesters.  
           [0100]    The acids can be introduced into the olefin type polymer by grafting or by any direct method (copolymerization). The amount of acid used for modification or denaturation preferably range from 0.1 to 20 by mass with respect to the mass amount of olefin type polymer.  
           [0101]    The acid-modified styrene type thermoplastic elastomers (c2) may be the polymers obtained by introducing, as acid components, unsaturated carboxylic acids or their derivatives (e.g. acid anhydrides or esters) into styrene type thermoplastic elastomers (b2). The types of unsaturated carboxylic acids or their derivatives, the method of their introduction and the amount used are the same as described above for the case of component (c1).  
           [0102]    The acid-modified polyethylene (c3) having a density of 0.920 or less may be the polymers obtained by introducing, as acid components, unsaturated carboxylic acids or their derivatives (e.g. acid anhydrides or esters) into relatively low density polyethylene (e.g. so-called ultra-low density polyethylene such as ethylene-octene copolymers). The types of unsaturated carboxylic acids or their derivatives, the method of their introduction and the amount used are the same as described above for the case of component (c1).  
           [0103]    When the density of acid modified polyethylene is more than 0.920, the hardness of the composition is increased and its flexibility is lowered.  
           [0104]    The acid modified rubber (c4) may be obtained, for example, by introducing the above-mentioned unsaturated carboxylic acids or their derivatives into a rubber. Examples of such rubber include ethylene-propylene rubber, ethylene-propylene-diene rubber or the like. The types of unsaturated carboxylic acids or their derivatives, the method of their introduction and the amount used are the same as described above for the case of component (c1).  
           [0105]    The amount of component (c) represents from 5 to 40 parts by mass, preferably 10 to 40 parts by mass, in the total of 100 parts by mass consisting of component (a), component (b1) or (b2) and component (c).  
           [0106]    When the amount of component (c) is greater than the above-mentioned upper limit, the wear resistance of the composition is lowered. Conversely, when its amount is less than the above-mentioned lower limit, the flexibility and formability of the composition tends to decrease.  
           [0107]    Examples of metal hydroxides (d) include magnesium hydroxide, aluminum hydroxide, and the like. Metal hydroxide particles need not be specifically treated. However, the surface may also be treated with a surface treatment agent such as coupling agents, in particular, silane coupling agents (e.g. amino silane coupling agent, vinyl silane coupling agent, epoxy silane coupling agent, methacryloxysilane coupling agent) or optionally higher fatty acids (e.g. stearic acid, oleic acid or the like).  
           [0108]    A silane coupling agent typically contains a Si—O bond which can form a bond with hydroxides. Among metal hydroxides, a preferred compound is magnesium hydroxide or aluminium hydroxide whose surface is treated with a coupling agent, preferably a silane coupling agent, in particular an aminosilane coupling agent.  
           [0109]    The particles of metal hydroxides need not be pre-treated with a coupling agent. Instead, they may be mixed directly with a resin, then supplemented with a coupling agent, according to a method called “integral blending”.  
           [0110]    The amount of metal hydroxide usually represents from 30 to 250 parts by mass, preferably from 50 to 200 parts by mass, of the total of component (a), component (b1) or (b2) and component (c) representing 100 parts by mass.  
           [0111]    Any known additive may be added into the composition in such an amount that does not damage preferable characteristics of the composition. Examples of the above additives include those usually added into olefin type resins such as heat stabilizers (e.g. oxidation-preventing agents), metal-inactivating agents (copper-pollution preventing agents), lubricants (fatty acids, fatty acid amides, metallic soaps, hydrocarbons e.g. wax, esters, silicone type lubricants), light stabilizers, core-forming agents, electrification-preventing agents, colorants, flame retardant adjuvants, (e.g. zinc borate, silicone type flame retardant, nitrogen type retardant), coupling agents (e.g. silane type coupler, titanate type coupler), softening agents (e.g. process oils), cross-linking adjuvants (poly functional monomers and the like).  
           [0112]    The resin composition of the invention may be prepared by mixing and/or kneading the components cited above according to any known method.  
           [0113]    The resin composition of the invention may be cross-linked according to any known method e.g. electron beam irradiation.  
           [0114]    The resin composition of the present invention may be used for coating electrical cables, in particular electrical cables for vehicles according to any known method.  
           [0115]    The above, and the other features and advantages of the present invention will be made apparent from the following description of the preferred examples, given as non-limiting examples, with references to the following Examples and Comparative Examples. 
       
    
    
     EXAMPLES 1 TO 10 AND COMPARATIVE EXAMPLES 1 TO 9  
       [0116]    The components shown in Tables 1 to 4 were mixed together in the amounts (parts by mass) indicated therein, kneaded in a temperature range of 180° C. to 260° C., and extruded into pellets by a two-axis extruder. The pellets were dried and extruded and shaped around a conductor element (7/0.30) having a cross section of 0.5 mm 2 , so as to yield a coating of 0.28 mm thick. The coated resin composition was then cross-linked by electron beam irradiation.  
         [0117]    The extrusion-shaping was performed using a nipple and die respectively having a diameter of about 0.93 mm and about 1.45 mm. The extrusion temperatures for the die and cylinder were respectively about 180° C. to about 250° C. and about 160° C. to about 240° C. The extrusion line speed was 100 m/min.  
         [0118]    The electron beam irradiation conditions were as follows.  
         [0119]    Device: EPS-750 KV  
         [0120]    Irradiation intensity: 120 KGy  
         [0121]    The following properties of the coated electrical cables obtained in Examples 1 to 10 and Comparative Examples 1 to 9 were evaluated.  
         [0122]    Flexibility:  
         [0123]    The flexibility was evaluated on the basis of resistance feeling, when the electrical cable was bent manually.  
         [0124]    Wear Resistance and Flame Retardant Quality  
         [0125]    Wear resistance and flame retardant quality were measured according to Standards JASO D 611. As to wear resistance, the results were considered good when the minimum value among 3 samples tested was more than 150 times.  
         [0126]    Formability  
         [0127]    The formability was evaluated by observing whether or not whiskers were formed when coatings were peeled at the end portion of electrical cables. The results are shown in Tables 1 to 4  
                                                                 TABLE 1                                   Example   Example   Example   Example   Example           1   2   3   4   5                                    HDPE  1)     65   50   65   30   40       LLDPE  2)         EVA  3)     30   10       65   30       EEA  4)             5       MAH-   5   40   30       30       EVA  5)         MAH-               5       EEA  6)         magnesium   100   120   100   250   30       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   4   4   2   4       linking       ad-       juvant  9)         Total   205   225   203   355   131       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0128]    [0128]                                                                 TABLE 2                                   Example   Example   Example   Example   Example           6   7   8   9   10                                    HDPE  1)         50   50   70   40       LLDPE  2)     90       EVA  3)     5   30       10   40       EEA  4)             30       MAH-   5   20   20       20       EVA  5)         MAH-               20       EEA  6)         magnesium   40   90   100   120   30       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   2   4   4   2   2       linking       agent  9)         Total   143   195   205   223   133       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0129]    [0129]                                                                 TABLE 3                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 1   Example 2   Example 3   Example 4   Example 5                                    HDPE  1)     100       20               LLDPE  2)                 30       EVA  3)         100       70   50       PP  10)         MAH-EVA  5)             80       50       MAH-PP  11)         magnesium   100   80   50   100   30       hydroxide  7)         anti-aging agent  8)     1   1   1   1   1       cross-linking   4   2   2   2   2       agent  9)         Total   205   183   153   203   133       Flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant   passed   passed   passed   passed   passed       quality       Formability   failed   passed   passed   passed   passed                    
         [0130]    [0130]                                                         TABLE 4                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 6   Example 7   Example 8   Example 9                                    HDPE 1)     65   60   85   70       LLDPE 2)         EVA 3)         10   10   25       PP 10)     30       MAH-EVA 5)     5       5   5       MAH-PP 11)         30       magnesium   30   200   10   300       hydroxide 7)         anti-aging   1   1   1   1       agent 8)         cross-linking   2   4   2   2       agent 9)         Total   133   305   112   403       flexibility   failed   failed   passed   failed       wear resistance   passed   passed   passed   passed       flame retardant   passed   passed   failed   passed       quality       formability   failed   failed   passed   failed                                                                                                            
         [0131]    From the results of Comparative Examples 1 to 5, it can be understood that, when the amount of any one component chosen among components (a), (b1) and (c1) is outside the range defined in the present invention, at least one of the tested physical properties is not satisfied.  
         [0132]    The results of Comparative Examples 6 and 7 show that, when any one of component (b1) and component (c1) is not used, the flexibility and formability of the composition deteriorate.  
         [0133]    The results of Comparative Examples 8 and 9 indicate that, when the amount of magnesium hydroxide, a flame retardant (d) is too small, the flame retardant quality of the composition deteriorates. Conversely, when this amount is too large, the flexibility and formability of the composition deteriorate.  
       EXAMPLES 11 TO 20 AND COMPARATIVE EXAMPLES 10 TO 18  
       [0134]    The components shown in Tables 5 to 8 were used in the amounts indicated therein (parts by mass). Coated electrical cables were produced through the methods described for Examples 1 to 10, and the properties of the obtained coating were evaluated. The results thus obtained are given in Tables 5 to 8.  
                                                                 TABLE 5                                   Example   Example   Example   Example   Example           11   12   13   14   15                                    HDPE  1)     60   50   65   30   50       LLDPE  2)         EVA  3)     35   10       65   30       EEA  4)             5       MAH-   5   40   30   5   20       SEBS  12)         MAH-PP  11)         magnesium   120   100   100   250   30       hydroxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-linking   4   4   2   4   2       agent  9)         Total   225   205   203   355   133       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0135]    [0135]                                                                 TABLE 6                                   Example   Example   Example   Example   Example           16   17   18   19   20                                    HDPE  1)         50   50   70   60       LLDPE  2)     90       EVA  3)     5   30       10   20       EEA  4)             30       MAH-   5   20   20   20   20       SEBS  12)         MAH-PP  11)         magnesium   50   90   100   120   30       hydroxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-linking   4   4   4   4   4       agent  9)         total   155   195   205   225   135       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0136]    [0136]                                                                 TABLE 7                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 10   Example 11   Example 12   Example 13   Example 14                                    HDPE  1)     100       20               LLDPE  2)                 20       EVA  3)         100       80   50       PP  10)         MAH-SEBS  12)             80       50       MAH-PP  11)         magnesium   90   100   80   100   30       hydroxide  7)         anti-aging agent  8)     1   1   1   1   1       cross-linking agent  9)     4   2   4   4   4       Total   195   203   185   205   135       flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant quality   passed   passed   passed   passed   passed       formability   passed   passed   passed   passed   passed                    
         [0137]    [0137]                                                         TABLE 8                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 15   Example 16   Example 17   Example 18                                    HDPE 1)     55   60   75   80       LLDPE 2)         EVA 3)         10   5   10       PP 10)     40       MAH-SEBS 12)     5       20   20       MAH-PP 11)         30       magnesium   30   180   10   300       hydroxide 7)         anti-aging   1   1   1   1       agent 8)         cross-linking   2   2   4   4       agent 9)         total   133   283   115   405       flexibility   failed   failed   passed   failed       wear resistance   passed   passed   passed   passed       flame retardant   passed   passed   failed   passed       quality       formability   failed   failed   passed   failed                                            
         [0138]    From the results of Comparative Examples 10 to 14, it can be understood that, when the amount of any one component chosen among component (a), (b1) and (c2) is outside the range defined in the present invention, at least one of the physical properties tested is not satisfied.  
         [0139]    The results of Comparative Example 15 show that, when an olefin polymer (b1) containing intra molecular oxygen atoms is not used, the flexibility and formability of the composition deteriorate.  
         [0140]    The results of Comparative Example 16 indicate that, when an acid modified styrene type thermoplastic elastomer (c2) is not used, the flexibility and formability of the composition are lowered.  
         [0141]    The results of Comparative Examples 17 and 18 show that, when the amount of magnesium hydroxide, a flame retardant (d), is too small, the flame retardant quality of the composition is poor. Conversely, when this amount is too large, the flexibility and formability of the composition deteriorate.  
       EXAMPLES 21 TO 30 AND COMPARATIVE EXAMPLES 19 TO 27  
       [0142]    The components shown in Tables 9 to 12 were used in the amounts (parts by mass) indicated therein, and coated electrical cables were produced according to the methods mentioned for Examples 1 to 10. The properties of the coatings obtained were then evaluated. The results are shown in Tables 9 to 12.  
                                                                 TABLE 9                                   Example   Example   Example   Example   Example           21   22   23   24   25                                    HDPE  1)     65   50   65   30   50       LLDPE  2)         EVA  3)     30   10   5       30       EEA  4)                 65       MAH-   5   40   30   5   20       VLDPE  13)         MAH-PP  11)         magnesium   110   100   120   250   30       hydroxide  7)         Anti-aging   1   1   1   1   1       agent  8)         cross-linking   2   4   4   4       agent  9)         total   213   205   225   355   131       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0143]    [0143]                                                                 TABLE 10                                   Example   Example   Example   Example   Example           26   27   28   29   30                                    HDPE  1)         50   50   70   40       LLDPE  2)     90       EVA  3)     5   30       10   40       EEA  4)             30       MAH-   5   20   20   20   20       VLDPE  13)         MAH-PP  11)         magnesium   40   90   120   100   30       hydroxide  7)         Anti-aging   1   1   1   1   1       agent  8)         cross-linking   4   4   4   4   2       agent  9)         total   145   195   225   205   133       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0144]    [0144]                                                                 TABLE 11                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 19   Example 20   Example 21   Example 22   Example 23                                    HDPE  1)     100       10               LLDPE  2)                 30       EVA  3)         100       70   50       PP  10)         MAH-VLDPE  13)             90       50       MAH-PP  11)         magnesium   100   80   40   100   30       hydroxide  7)         anti-aging agent  8)     1   1   1   1   1       cross-linking agent  9)     4   2   4   2   2       Total   205   183   145   203   133       flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant   passed   passed   passed   passed   passed       quality       formability   failed   passed   passed   passed   passed                    
         [0145]    [0145]                                                         TABLE 12                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 24   Example 25   Example 26   Example 27                                    HDPE  1)     55   60   85   70       LLDPE  2)         EVA  3)         10   10   25       PP  10)     40       MAH-   5       5   5       VLDPE  13)         MAH-PP  11)         30       magnesium   50   200   10   300       hydroxide  7)         Anti-aging   1   1   1   1       agent  8)         cross-linking   4   4   2   2       agent  8)         total   135   305   112   403       flexibility   failed   failed   passed   failed       wear   passed   passed   passed   passed       resistance       flame   passed   passed   failed   passed       retardant       quality       formability   failed   failed   passed   failed                                            
         [0146]    The results of Comparative Examples 19 to 23 show that, when the amount of any one component chosen among components (a), (b1) and (c3) is outside the range defined in the present invention, at least one of the properties tested is not satisfied.  
         [0147]    The results of Comparative Example 24 indicate that, when an olefin polymer (b1) containing intra-molecular oxygen atoms is not used, the flexibility and formability of the composition are poor.  
         [0148]    The results of Comparative Example 25 show that, when an acid modified styrene type thermoplastic elastomer (c3) is not used, the flexibility and formability of the composition are poor.  
         [0149]    From the results of Comparative Examples 26 and 27, it can be understood that, when the amount of magnesium hydroxide, flame retardant as component (d), is too small, the flame retardant quality of the composition is poor. Conversely, when this amount is too large, the flexibility and formability of the composition deteriorate.  
       EXAMPLES 31 TO 40 AND COMPARATIVE EXAMPLES 28 TO 36  
       [0150]    The components shown in Tables 13 to 16 were used in the amounts (parts by mass), to produce coated electrical cables according to the methods described for Examples 1 to 10. The properties of the coatings were then evaluated. The results are shown in Tables 13 to 16.  
                                                                 TABLE 13                                   Example   Example   Example   Example   Example           31   32   33   34   35                                    HDPE  1)     65   50   65   30   50       LLDPE  2)         EVA  3)     30   10   5       30       EEA  4)                 65       MAH-   5   40   30   5       EPM  14)         MAH-                   20       EPDM  15)         magnesium   100   120   120   250   30       hy-       droxide  7)         Anti-aging   1   1   2   1   1       agent  8)         cross-   4   4   2   4   4       linking       agent  9)         total   205   225   224   355   135       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0151]    [0151]                                                                 TABLE 14                                   Example   Example   Example   Example   Example           36   37   38   39   40                                    HDPE  1)         50   50   70   40       LLDPE  2)     90       EVA  3)     5   30       10   40       EEA  4)             30       MAH-   5   20   20   20       EPM  14)         MAH-                   20       EPDM  15)         magnesium   40   90   120   100   90       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   4   4   4   4   2       linking       agent  9)         total   145   195   225   205   193       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0152]    [0152]                                                                 TABLE 15                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 28   Example 29   Example 30   Example 31   Example 32                                    HDPE  1)     100       10               LLDPE  2)                 30       EVA  3)         100       70   50       PP  10)         MAH-EPM  14)             90       50       MAH-PP  11)         magnesium hydroxide  7)     100   80   60   100   30       anti-aging agent  8)     1   1   1   1   1       cross-linking agent  9)     4   2   4   2   2       Total   205   183   165   203   133       Flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant quality   passed   passed   passed   passed   passed       formability   failed   passed   passed   passed   passed                    
         [0153]    [0153]                                                         TABLE 16                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 33   Example 34   Example 35   Example 36                                    HDPE  1)     55   60   85   70       LLDPE  2)         EVA  3)         10   10   25       PP  10)     40       MAH-   5       5   5       VLDPE  13)         MAH-PP  11)         30       magnesium   50   180   10   300       hydroxide  7)         Anti-aging   1   1   1   1       agent  8)         cross-linking   2   4   2   2       agent  9)         total   133   285   112   403       flexibility   failed   failed   passed   failed       wear   passed   passed   passed   passed       resistance       flame   passed   passed   failed   passed       retardant       quality       formability   failed   failed   passed   failed                                                    
         [0154]    The results of Comparative Examples 28 to 32 suggest that, when the amount of any one component chosen among components (a), (b1) and (c4) is outside the range defined in the present invention, at least one of the properties evaluated is not satisfied.  
         [0155]    The results of Comparative Example 33 show that, when an olefin polymer (b1) containing intra-molecular oxygen atoms is not used, the flexibility and formability of the composition are poor.  
         [0156]    The results of Comparative Example 34 indicate that, when an acid modified rubber (c4) is not used, the flexibility and formability of the composition are poor.  
         [0157]    The results of Comparative Examples 35 and 36 show that, when the amount of magnesium hydroxide, which is a flame retardant (component (d)), is too small, the flame retardant quality of the composition is poor. However, when this amount is too large, the flexibility and formability of the composition are deteriorated.  
       EXAMPLES 41 TO 50 AND COMPARATIVE EXAMPLES 37 TO 45  
       [0158]    The components shown in Tables 17 to 20 were used in the amounts (parts by mass), to produce coated electrical cables according to the methods described for Examples 1 to 10. The properties of the coatings were then evaluated. The results are shown in Tables 17 to 20.  
                                                                 TABLE 17                                   Example   Example   Example   Example   Example           41   42   43   44   45                                    HDPE  1)     65   50   65   30   50       LLDPE  2)         SEBS  16)     30   10       65   30       SEPS  17)             5       MAH-   5   40   30   5   20       SEBS  12)         MAH-PP  11)         magnesium   90   100   90   250   30       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   4   4   4   2   2       linking       agent  9)         Total   195   205   195   353   133       flexibility   passed   passed   passed   passed   passed       Wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0159]    [0159]                                                                 TABLE 18                                   Example   Example   Example   Example   Example           46   47   48   49   50                                    HDPE  1)         50   50   70   60       LLDPE  2)     90       SEBS  16)     5   30       10   20       SEPS  17)             30       MAH-   5   20   20   20   20       SEBS  12)         MAH-PP  11)         magnesium   40   120   90   100   30       hydroxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   2   2   4   4   4       linking       agent  9)         total   153   223   195   205   135       flexibility   passed   passed   passed   passed   passed       wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0160]    [0160]                                                                 TABLE 19                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 37   Example 38   Example 39   Example 40   Example 41                                    HDPE  1)     100       20               LLDPE  2)                 20       SEBS  16)         100       80   70       PP  10)         MAH-SEBS  12)             80       30       MAH-PP  11)         magnesium hydroxide  7)     90   120   80   100   30       anti-aging agent  8)     1   1   1   1   1       cross-linking agent  9)     4   2   4   4   4       Total   195   223   185   205   135       Flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant quality   passed   passed   passed   passed   passed       formability   failed   passed   passed   passed   passed                    
         [0161]    [0161]                                                         TABLE 20                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 42   Example 43   Example 44   Example 45                                    HDPE  1)     55   60   85   80       LLDPE  2)         SEBS  16)         10   5   10       PP  10)     40       MAH-   5       10   10       SEBS  12)         MAH-PP  11)         30       magnesium   30   200   10   300       hydroxide  7)         Anti-aging   1   1   1   1       agent  8)         cross-linking   2   4   4   4       agent  9)         total   133   305   115   405       flexibility   failed   failed   passed   failed       wear   passed   passed   passed   passed       resistance       flame   passed   passed   failed   passed       retardant       quality       formability   failed   failed   passed   failed                                                            
         [0162]    From the results of Comparative Examples 37 to 41, it can be understood that, when the amount of any one component chosen among components (a), (b2) and (c2) is outside the range defined in the present invention, at least one of the physical properties evaluated is not sufficient.  
         [0163]    The results of Comparative Example 42 indicate that, when an olefin polymer (b2) containing intra-molecular oxygen atoms is not used, the flexibility and formability of the composition are not sufficient.  
         [0164]    The results of Comparative Example 43 show that, when an acid modified styrene type thermoplastic elastomer (c2) is not used, the flexibility and formability of the composition are poor.  
         [0165]    The results of Comparative Examples 44 and 45 suggest that, when the amount of magnesium hydroxide, which is a flame retardant (component (d)), is too small, the flame retardant quality of the composition is poor. However, when this amount is too large, the flexibility and formability of the composition are poor.  
       EXAMPLES 51 TO 60 AND COMPARATIVE EXAMPLES 46 TO 54  
       [0166]    The components shown in Tables 21 to 24 were used in the amounts (parts by mass), to produce coated electrical cables according to the methods described for Examples 1 to 10. The properties of the coatings were then evaluated. The results are shown in Tables 21 to 24.  
                                                                 TABLE 21                                   Example   Example   Example   Example   Example           51   52   53   54   55                                    HDPE  1)     65   50   60   30   50       LLDPE  2)         SEBS  16)     30   10       65   30       SEPS  17)             5       MAH-       EVA  5)         MAH-   5   40   35   5   30       EEA  6)         magnesium   90   100   100   250   30       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   4   4   2   4   4       linking       agent  9)         Total   195   205   203   355   135       flexibility   passed   passed   passed   passed   passed       Wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                  
 
         [0167]    [0167]                                                                 TABLE 22                                   Example   Example   Example   Example   Example           56   57   58   59   60                                    HDPE  1)         50   50   70   60       LLDPE  2)     90       SEBS  16)         30   20       SEPS  17)     5           10   20       MAH-   5   20       20       EVA  5)         MAH-           30       20       EEA  6)         magnesium   70   120   100   120   30       hy-       droxide  7)         anti-aging   1   1   1   1   1       agent  8)         cross-   4   4   4   4   4       linking       agent  9)         Total   175   225   205   225   135       flexibility   passed   passed   passed   passed   passed       Wear   passed   passed   passed   passed   passed       resistance       flame   passed   passed   passed   passed   passed       retardant       quality       formability   passed   passed   passed   passed   passed                    
         [0168]    [0168]                                                                 TABLE 23                                   Comparative   Comparative   Comparative   Comparative   Comparative           Example 46   Example 47   Example 48   Example 49   Example 50                                    HDPE  1)     100       20               LLDPE  2)                 20       SEBS  16)         100       80   50       PP  10)         MAH-EVA  5)             80       50       MAH-PP  11)         magnesium hydroxide  7)     90   120   50   100   40       anti-aging agent  8)     1   1   1   1   1       cross-linking agent  9)     4   2   2   4   4       Total   195   223   153   205   145       Flexibility   failed   passed   passed   passed   passed       wear resistance   passed   failed   failed   failed   failed       flame retardant quality   passed   passed   passed   passed   passed       Formability   failed   passed   passed   passed   passed                    
         [0169]    [0169]                                                         TABLE 24                                   Compar-   Compar-   Compar-   Compar-           ative   ative   ative   ative           Example 51   Example 52   Example 53   Example 54                                    HDPE  1)     55   60   90   85       LLDPE  2)         SEBS  16)         5   5   5       PP  10)     40       MAH-EVA  5)     5       5   10       MAH-PP  11)         35       magnesium   200   180   10   300       hydroxide  7)         Anti-aging   1   1   1   1       agent  8)         cross-linking   2   2   4   4       agent  9)         total   303   283   115   405       flexibility   failed   failed   passed   failed       wear   passed   passed   passed   passed       resistance       flame   passed   passed   failed   passed       retardant       quality       formability   failed   failed   passed   failed                                            
         [0170]    The results of Comparative Examples 46 to 50 indicate that, when the amount of any one component chosen among components (a), (b2) and (c1) is outside the range defined in the present invention, at least one of the properties evaluated is not satisfactory.  
         [0171]    The results of Comparative Example 51 suggest that, when an olefin polymer (b2) containing intra-molecular oxygen atoms is not used, the flexibility and formability of the composition are poor.  
         [0172]    The results of Comparative Example 52 show that, when an acid modified styrene type thermoplastic elastomer (c1) is not used, the flexibility and formability of the composition are poor.  
         [0173]    The results of Comparative Examples 53 and 54 indicate that, when the amount of magnesium hydroxide, flame retardant component (d), is too small, the flame retardant quality of the composition is poor, whereas, when this amount is too large, the flexibility and formability of the composition are poor.  
         [0174]    Although the invention has been described with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to the particulars disclosed and extends to all equivalents within the scope of the claims.  
         [0175]    The present disclosure relates to subject matter contained in priority Japanese Application No. 2001-382711, filed on Dec. 17, 2001, which is herein expressly incorporated by reference in its entirety.