JP2001023441A - Halogen-free flame-retardant resin composition and flame-retardant electric wire / cable using the same - Google Patents

Abstract

(57) Abstract: Provided is a non-halogen flame-retardant resin composition having excellent flame retardancy, good mechanical properties and electrical insulation, and suitable for use as an insulating material for electric wires and cables. SOLUTION: Based on 100 parts by weight of a polyolefin resin mixture containing 40% by weight or more of ethylene-propylene rubber, 8 parts by weight or more and 100 parts by weight or less of aluminum hydroxide, 3 parts by weight or more and 50 parts by weight or less of a molybdenum compound.
And at least 45 parts by weight of an inorganic metal-based flame retardant other than these 2
A non-halogen flame-retardant resin composition containing not more than 00 parts by weight. An insulating layer was formed using this non-halogen flame-retardant resin composition, and the insulation resistance at 25 ° C. was 300 MΩ ·
Flame-retardant wires and cables over km.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-halogen flame-retardant resin composition which is excellent in flame retardancy, does not contain halogen, and has good electric insulation when used in an insulating layer of an electric wire or the like. .

[0002]

2. Description of the Related Art Polyvinyl chloride (PVC) compositions having good electrical insulation properties and self-extinguishing flame retardancy have been widely used as insulating materials for forming insulating layers of electric wires and cables. I have. However, since the PVC composition contains chlorine (Cl) which is a halogen, there is a possibility that a corrosive gas such as HCl or a toxic gas such as dioxin may be generated during combustion. For this reason, it is difficult to incinerate when PVC products become waste. At present, landfill disposal is used. However, Pb-based stabilizers are often used as additives in PVC compositions, and there is a problem that they are eluted into soil, etc., and are treated as industrial waste. Is getting harder.

[0003]

On the other hand, PVC
Halogen-free polyethylene (PE), polypropylene (PP), ethylene-
If a polyolefin resin composition such as propylene rubber (EPR) is used, no harmful gas is generated at the time of combustion, so it can be incinerated. However, these halogen-free polyolefin resin compositions are more flame-retardant than PVC. There was a disadvantage that the properties were poor. For example, when comparing the oxygen index (OI), which is one of the evaluation scales for flame retardancy of the resin composition, PV
C has an OI of 23 to 40, whereas PE, PP,
It can be seen that the OI such as EPR is inferior to about 17 to 19. Among the halogen-free polyolefin resin compositions, ethylene-vinyl acetate copolymers (EV
A) has an OI of about 19 to 21, PE, PP, EP
Although they are higher than R, they have the drawback that they are slightly inferior in electrical insulation.

[0004] Conventionally, non-halogen polyolefin resin compositions having a low OI value include Mg (OH) ₂ ,
Many attempts have been made to improve the flame retardancy by adding a metal hydroxide such as Al (OH) ₃ . However, the desired high flame retardancy cannot be obtained only by adding the metal hydroxide, or if a large amount of the metal hydroxide is added to obtain the desired high flame retardancy, other than the flame retardancy such as mechanical properties. However, there is a problem that the characteristics may be remarkably deteriorated. Therefore, for example, by blending a non-halogen polyolefin resin composition having a relatively high OI with a non-halogen polyolefin resin composition having a relatively low OI, a method of preventing the deterioration of mechanical properties by suppressing the amount of metal hydroxide added. However, as described above, the halogen-free polyolefin resin composition having a relatively high OI is inferior in electrical insulation, so that the resin composition obtained by blending causes a decrease in electrical insulation, resulting in electric wires and cables. It may be inconvenient to apply to the insulating layer.

An object of the present invention is to solve the problems in the prior art as described above. That is,
An object of the present invention is to provide a non-halogen flame-retardant resin composition which is excellent in flame retardancy, has good mechanical properties and electrical insulation, and can be suitably used as an insulating material for electric wires and cables.

[0006]

The object of the present invention is to provide a polyolefin resin mixture containing at least 40% by weight of ethylene-propylene rubber and 100 parts by weight of aluminum hydroxide in an amount of from 8 parts by weight to 100 parts by weight of a molybdenum compound. The problem can be solved by a non-halogen flame-retardant resin composition comprising at least 50 parts by weight and at most 50 parts by weight, and at least 45 parts by weight and at most 200 parts by weight of an inorganic metal-based flame retardant other than these. By forming an insulating layer using the halogen-free flame-retardant resin composition of the present invention, a flame-retardant electric wire or cable having an insulation resistance at 25 ° C. of 300 MΩ · km or more can be obtained.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The polyolefin resin mixture used in the present invention is an ethylene-propylene rubber (EP).
R) and another polyolefin-based resin. Other polyolefin resins mixed with EPR are preferably ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-methyl acrylate copolymer (EMA). One type may be used, or two or more types may be used in combination.
Further, during or after polymerization of another polyolefin resin mixed with EPR, an acid-modified polyolefin modified by reacting with an unsaturated carboxylic acid such as maleic anhydride, acrylic acid, fumaric acid, or a derivative thereof, for example. Can also be used. E in polyolefin resin mixture
The content ratio of PR is 40% by weight or more and 90% by weight or less, and more preferably 40% by weight or more and 75% by weight or less. When the content ratio of EPR is large, the effect of improving the flame retardancy by mixing with other polyolefin-based resin is reduced. Conversely, when the content ratio of EPR is small and the content ratio of other polyolefin-based resin is large, the difficulty is increased. Although the flammability increases, the electrical insulation deteriorates greatly. Further, in the present invention, by using EPR as an essential component among the polyolefin-based resins, it is possible to maintain a high electric insulation property even if a resin such as EVA is contained, and to obtain a thermally and mechanically stable resin composition. Can be obtained.

[0008] The aluminum hydroxide used in the present invention is used for improving the affinity with the resin and the thermal decomposition property.
Surface treatment with stearic acid, oxalate anion or the like may be used. The addition amount of aluminum hydroxide is from 8 parts by weight to 100 parts by weight, more preferably from 10 parts by weight to 50 parts by weight, based on 100 parts by weight of the polyolefin resin mixture. If the added amount of aluminum hydroxide is too small, favorable flame retardancy cannot be obtained, and if it is too large, the resulting non-halogen flame-retardant resin composition is undesirably deteriorated in mechanical properties and the like.

Examples of the molybdenum compound used in the present invention include oxides such as molybdenum trioxide, sulfides such as molybdenum disulfide, and molybdates such as ammonium molybdate, calcium molybdate, and sodium molybdate. Can be These may be used alone or in combination of two or more. The amount of the molybdenum-based compound added is 100
3 parts by weight or more and 50 parts by weight or less with respect to parts by weight,
More preferably, it is 3 parts by weight or more and 20 parts by weight or less. If the addition amount of the molybdenum-based compound is too small, favorable flame retardancy cannot be obtained, and if the addition amount is too large, the cost of raw materials increases but the further improvement in flame retardancy cannot be expected much.

The inorganic metal-based flame retardant in the present invention is an inorganic metal-based flame retardant other than the above-mentioned aluminum hydroxide and molybdenum-based compounds. Preferably, magnesium hydroxide is used. Calcium carbonate, zinc borate, magnesium carbonate You may use together. These inorganic metal-based flame retardants may be surface-treated with stearic acid, oxalate anion, or the like in order to improve the affinity with the resin and the thermal decomposition characteristics. In the present invention, the addition amount of the inorganic metal-based flame retardant is 10
It is 45 parts by weight or more and 200 parts by weight or less, more preferably 45 parts by weight or more and 150 parts by weight or less with respect to 0 parts by weight. If the added amount of the inorganic metal-based flame retardant is too small, favorable flame retardancy cannot be obtained, and if it is too large, the resulting non-halogen flame-retardant resin composition is undesirably deteriorated in mechanical properties and the like.

It is preferable to further add an antioxidant. Although it does not specifically limit as an antioxidant, For example, a phenol type, an amine type, etc. can be used preferably. If the amount of the antioxidant is too small, the effect of addition cannot be obtained, and if it is too large, blooming or bleed-out may occur. Therefore, 0.1 part by weight or more per 100 parts by weight of the polyolefin resin mixture. 0 parts by weight or less is preferred. The halogen-free flame-retardant resin composition of the present invention may be crosslinked or non-crosslinked. Since the heat resistance temperature of the resin is improved by the cross-linking, the resin may be cross-linked as necessary, for example, in the application of the resin. The crosslinking method can be performed by a known method such as a crosslinking agent, electron beam irradiation, and silane crosslinking. Furthermore, besides the above-mentioned compounding agents, appropriate additives such as ultraviolet absorbers, copper harm inhibitors, pigments, dyes and other coloring agents, and a small amount of inorganic fine powder such as talc may be compounded according to the intended use. However, additives that do not contain halogen and lead (Pb) are selected. Further, it is preferable that the harmful heavy metal such as cadmium (Cd) is not contained as much as possible, and it is preferable that the content of the harmful heavy metal in the non-halogen flame-retardant resin composition of the present invention is suppressed to less than 0.1% by weight. Further, the non-halogen flame-retardant resin composition of the present invention may have a degree of foaming of less than 10%.

In the present invention, the addition of aluminum hydroxide, the above-mentioned molybdenum-based compound, and an inorganic metal-based flame retardant to the above-mentioned polyolefin-based resin mixture as essential components results in deterioration of the mechanical properties of the resin composition and electrical insulation. Preferred flame retardancy can be achieved while preventing deterioration of the properties. In particular, according to the present invention, the mixing ratio of aluminum hydroxide and the molybdenum-based compound can be easily controlled, which is preferable in that the mixing can be appropriately performed and the cost can be reduced. For example, according to the present invention, preferable flame retardancy can be achieved at a lower cost than using a large amount of a composite of a molybdenum-based compound and a metal hydroxide. By adding other inorganic metal-based flame retardants in addition to aluminum hydroxide and molybdenum-based compounds, it can exhibit a flame-retardant effect over a wide range of combustion temperatures from the initial stage to the later stage of combustion. High flame retardancy can be achieved while suppressing the addition amount of the relatively expensive molybdenum-based compound, and a practical resin composition can be obtained in terms of cost.

The resin composition of the present invention, which is excellent in flame retardancy, electrical insulation and mechanical properties, is particularly suitable as a material for forming an insulation layer of electric wires and cables, and has an insulation resistance of 300 MΩ · km. As described above (25 ° C.), a flame-retardant electric wire or cable excellent in mechanical properties and flame retardancy can be realized. Here, the value of the insulation resistance in the present invention is set at 25 ° C. by a method according to JIS C3005.
Is a value measured under the conditions of The flame retardancy of the flame-retardant resin composition of the present invention, when used as a coating material for electric wires and cables or similar products, was determined by the combustion test specified in the Electrical Appliance and Material Control Law and UL Standard, respectively. High flame retardancy that can pass one or both tests can be achieved.

The non-halogen flame-retardant resin composition of the present invention includes, for example, insulated wires, wires for electronic device wiring, wires for automobiles, wires for devices, power cords, insulated wires for outdoor power distribution, power cables, control cables, It is particularly suitable as an insulating material for various electric wires and cables such as communication cables, instrumentation cables, signal cables, moving cables, and marine cables. Types and inclusions, cases,
Auxiliary parts for electric wires and cables such as plugs and tapes (specifically, shrink tubing, rubber stress relief cones, etc.), electric products such as conduits, wiring ducts, and bus ducts, as well as agricultural sheets and water hoses It is also suitable for gas pipe coating materials, building interior materials, floor materials and the like. In particular, the non-halogen flame-retardant resin composition of the present invention,
Since the compounding ratio of the resin is optimized and the amount of flame retardant added is controlled so as not to be excessive,
When used for electric wires or power cords, a product having excellent flexibility, good plug bending characteristics, and excellent plug tracking resistance can be obtained.

[0015]

EXAMPLES Hereinafter, the effects of the present invention will be clarified by showing specific examples. As examples and comparative examples of the present invention,
Various components were blended in the blending ratios (unit: parts by weight) shown in Tables 1 and 2 below, and kneaded with a kneader to obtain a resin composition.
In order to conduct a combustion test, a resin composition after kneading was extrusion-coated on a 2 mm ² conductor with an extruder to form an insulating layer, and an electric wire having an outer diameter of 5 mm was manufactured. In addition, a crosslinking assistant and a crosslinking initiator were added to the resin composition in advance, and the resin composition was crosslinked by applying heat and pressure after extrusion coating. The combustion test was performed using the obtained electric wires in accordance with the 60 ° tilt combustion test established in the Electric Control Law combustion test and the vertical combustion test established in UL Standard VW-1. The results are shown in the table.
Further, the oxygen index (OI) measured according to the test method of JIS K7201, the tensile strength at break and the tensile elongation measured by the measurement method described in JIS K7127, JIS
The insulation resistance value (25 ° C.) was measured by the measurement method described in C3005. The results are shown in the table. The evaluation of the breaking strength is as follows: 0.4 kgf / mm ² or more
Others are indicated by x. The evaluation of elongation was shown as ○ for 300% or more, and as X for other cases. In addition, the evaluation of the insulation resistance value was shown as ○ for 300 MΩ · km or more, and as × for the others.

[0016]

[Table 1]

[0017]

[Table 2]

The respective resins and compounding agents shown in the above table are as follows. (1) EPR: Mooney viscosity ML ^{1 + 4} (100 ° C.) = 40,
Ethylene content 70mol%, propylene content 30mol%
(2) EVA: melt flow rate (hereinafter referred to as MFR) = 2.5, ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% (3) EEA: MFR = 0.5, Ethylene-ethyl acrylate copolymer with an ethyl acrylate content of 14% (4) Magnesium hydroxide: magnesium hydroxide treated with stearic acid surface (5) Aluminum hydroxide: aluminum hydroxide treated with oxalic acid (6) Antioxidant: large Nocrack 3 manufactured by Uchi Shinko Chemical Industry Co., Ltd.
00 (trade name) (7) Cross-linking aid: Actor ZMA (trade name) manufactured by Kawaguchi Chemical Co., Ltd. (8) Cross-linking initiator: dicumyl peroxide

From the results shown in Tables 1 and 2, in each of the examples shown in Table 1, good flame retardancy, mechanical properties and electrical insulation were achieved, while the content ratio of EPR was high. Comparative Example 1 having a small amount of 20 parts by weight had a low insulation resistance value, and Comparative Example 2 having a small amount of magnesium hydroxide of 30 parts by weight did not achieve high flame retardancy. In Comparative Example 3 as large as parts by weight and Comparative Example 4 as large as 150 parts by weight of aluminum hydroxide, the mechanical properties were significantly deteriorated. In Comparative Examples 5 and 6, since the amount of the molybdenum-based compound added was as large as 80 parts by weight, the raw material cost was increased and the cost was high, and the effect was commensurate with the increase in the added amount. No further improvement could be expected, and the mechanical properties were greatly degraded.

Each of the non-halogen flame-retardant resin compositions obtained in the above Examples has an oxygen index (OI) of more than 24 and has self-extinguishing flame retardancy equivalent to that of PVC. The resin composition hardly burns in a fire and emits a small amount of smoke. Also, because it does not contain halogen, it does not generate toxic gases such as dioxin and halogen gas during combustion,
Therefore, it can be incinerated and does not generate toxic gas in the event of a fire. Furthermore, since it does not contain a phosphorus compound, it is environmentally preferable, and since there is no elution of lead, landfill disposal is possible. Further, when the non-halogen flame-retardant resin composition of the above example is used as a covering material for an electric wire, it can pass one or both of a combustion test established by the Electrical Appliance and Material Control Law and UL standards. , Tensile strength at break and tensile elongation are both good, and the insulation resistance value can be as high as 300 MΩ · km or more. Is very high. Further, since the composition does not contain a silicone compound, the material cost can be reduced as compared with the composition using a silicone compound.

[0021]

As described above, according to the present invention, a flame-retardant resin composition containing no halogen, having excellent flame retardancy, and having good mechanical properties and electrical insulation properties can be obtained.
The non-halogen flame-retardant resin composition of the present invention is suitable as an insulating material for electric wires and cables, and by forming an insulating layer of electric wires and cables using this resin composition,
When the insulation resistance value is 300 MΩ · km or more (25 ° C.), the electrical insulation is good, and a highly practical flame-retardant wire or cable can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01B 3/44 H01B 3/44 F 7/295 7/34 B (72) Inventor Hirotaka Sawada 1-chome Kiba, Koto-ku, Tokyo 5-1 Fujikura Co., Ltd. (72) Inventor Jun Suzuki 1-5-1 Kiba, Koto-ku, Tokyo F-term (reference) 4J002 BB06X BB07X BB15W BB21X DE078 DE097 DE146 DE187 DE238 DF007 DG027 DK008 FB238 GQ01 5G303 AA06 AB20 BA12 CA11 5G305 AA02 AB01 AB25 BA12 BA13 CA01 CA51 CC03 CC11 CD13 5G315 CA03 CB02 CD02 CD04 CD13 CD14

Claims (2)

[Claims] 1. An ethylene-propylene rubber of 40% by weight
Based on 100 parts by weight of the polyolefin-based resin mixture containing above, aluminum hydroxide is 8 parts by weight or more and 100 parts by weight or less, molybdenum-based compound is 3 parts by weight or more and 50 parts by weight or less,
And at least 45 parts by weight of an inorganic metal-based flame retardant other than these 2
A non-halogen flame-retardant resin composition containing not more than 00 parts by weight. 2. A flame-retardant electric wire or cable having an insulating layer comprising the non-halogen flame-retardant resin composition according to claim 1 and having an insulation resistance at 25 ° C. of 300 MΩ · km or more.