Fire retardant thermoplastic resin composition and electric wire comprising the same

Abstract

Disclosed are a fire retardant thermoplastic resin composition suitable for preparing an electric wire, etc. by enhancing extrudability of a resin composition without hindering fire retardancy of the resin composition, and an electric wire comprising the same. The fire retardant thermoplastic resin composition comprises a matrix resin that comprises 20 to 35% by weight of a poly arylene ether resin, 20 to 35% by weight of a vinyl aromatic resin and 5 to 20% by weight of an olefin-based resin comprising a rubber ingredient, 1 to 10% by weight of a room-temperature liquid-type fire retardant, and 8 to 20% by weight of an ancillary fire retardant, based on 100% by weight of a mixture of a poly arylene ether resin, a vinyl aromatic resin, an olefin-based resin, a room-temperature liquid-type fire retardant and an ancillary fire retardant.

Claims

1. A fire retardant thermoplastic resin composition consisting of: a matrix resin that comprises 20 to 35% by weight of a poly arylene ether resin, 20 to 35% by weight of a vinyl aromatic resin and 5 to 20% by weight of an olefin-based resin; 4 to 7% by weight of a room-temperature liquid-type fire retardant; 7 to 15% by weight of a nitrogen-based fire retardant; 1 to 5% by weight of a second phosphorus-based fire retardant other than the room-temperature liquid-type fire retardant; and 3.3 to 6.4% by weight of an additive, based on the total amount of the resin composition, wherein the additive comprises at least one selected from the group consisting of lubricant, thermostabilizer, antioxidant, anti-dripping agent and organic filler.

2. The fire retardant thermoplastic resin composition according to claim 1, wherein the olefin-based resin is selected from the group consisting of low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene and mixtures of two or more thereof.

3. The fire retardant thermoplastic resin composition according to claim 1, wherein the room-temperature liquid-type fire retardant is a room-temperature liquid-type phosphorus-based fire retardant.

4. The fire retardant thermoplastic resin composition according to claim 3, wherein the room-temperature liquid-type phosphorus-based fire retardant is selected from the group consisting of bisphenol-A-diphenyl phosphate (BPADP), triphenyl phosphate (TPP), resorcinol bis-diphenyl phosphate (RDP) and mixtures of two or more thereof.

5. The fire retardant thermoplastic resin composition according to claim 1, wherein the nitrogen-based fire retardant is one or more selected from the group consisting of melamine polyphosphate, melamine pyrophosphate and melamine phosphate.

6. The fire retardant thermoplastic resin composition according to claim 1, wherein the second phosphorus-based fire retardant is one or more selected from the group consisting of metal phosphate, a phosphorus ester compound, phosphate, pyrophosphate, phosphonate, metal-substituted phosphinate and phosphanate.

7. The fire retardant thermoplastic resin composition according to claim 6, wherein the metal phosphate is aluminium phosphate, zinc phosphate or a mixture thereof.

8. The fire retardant thermoplastic resin composition according to claim 1, wherein a melt index of the fire retardant thermoplastic resin composition is 40 to 150 g/10 min.

9. An electric wire comprising the fire retardant thermoplastic resin composition according to claim 1.

Description

EXAMPLE

Examples 1 to 5, Comparative Examples 1 to 4 and Reference Examples 1 to 2

(1) Mixing was carried out according to ingredients and contents summarized in Table 1 below. Subsequently, a twin-screw extruder was set to 240 to 250° C. (temperature of feeder, to which materials are input, was set to 240° C. and the other parts were set to 250° C.), and extrusion was carried out by melting/kneading. Finally, drying was performed at 80° C. for four hours after pelletizing, and then the dried pellet was stood at room-temperature for one day. Subsequently, using a 9Φ HAAKE extruder manufactured by Thermo Scientific (Germany) as a wire coating extruder, a cable was extruded (extrusion conditions: temperature was set to 240 to 250° C. (a feeder (to which materials are input) was set to 240° C., other devices were set to 250° C.), and speed was set to 80 rpm, 30 m/min) was performed. Properties of produced specimens were evaluated and results are summarized in Table 1 below.

(2) Property evaluation was carried out as follows: Cable appearance evaluation: Evaluated with the naked eye according to a method described in UL 1581 Tensile strength and elongation: Measured according to a method described in UL 1581 Fire retardancy (VW-1): Measured according to a method described in UL 1581 Hardness (Shore A): Measured according to a method described in ASTM D 2240 Melt index (g/10 min): Measured for one minute after standing for four minutes under a load of 10 kg at 250□ and calculated according to ASTM D1238

(3) In addition, abbreviations of ingredients in Table 1 below are as follows: PPE: polyphenylene ether; PX-100F manufactured by Mitsubishi Engineering Plastic (MEP), Japan SBC 1: styrene block copolymer; SEBS G 1657 (styrene content: 13%) manufactured by Kraton, USA SBC 2: styrene block copolymer; SEBS A 1536 (styrene content: 42%) manufactured by Kraton, USA PP: polypropylene; EC5082 (ethylene butadiene rubber (EBR) content: 7%, melt index: 23 g/10 min.) manufactured by PolyMirae, Republic of Korea FR1: OP 1230 (phosphorus content: 23% to 24%) as metal phosphate, aluminum diethylphosphate, used as a second phosphorus-based fire retardant, manufactured by Clariant, Japan FR2: NONFLA 601 (nitrogen content: 39% to 42%, phosphorus content: 14% to 17%) as melamine polyphosphate used as nitrogen-based fire retardant), manufactured by DOOBON, Republic of Korea FR3: (Adeka) FP-600 as bisphenol-A-diphenylphosphate (BPADP), a liquid phosphorus-based fire retardant that is liquid at room temperature, manufactured by ADEKA, Japan

(4) TABLE-US-00001 TABLE 1 Classification Comparative Reference Examples Examples Examples Classification 1 2 3 4 5 1 2 3 4 1 2 PPE 29 29 33 33 29 29 29 29 29 29 29 SBC 1 11.7 11.7 11.7 11.7 11.7 11.7 11.7 11.7 11.7 11.7 11.7 SBC 2 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 PP 12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 FR1 3.4 2.5 2.5 2.5 2.5 — 3.4 7 8.4 3.4 3.4 FR2 12 12 12 12 12 11 12 12 12 12 17 FR3 5 7 5 4 9 15 — — — 3 3 Additive 6.4 5.3 3.3 4.3 3.3 0.8 11.4 7.8 6.4 8.4 3.4 Cable extrusion characteristics Extrudability ⊚ ◯ ⊚ ◯ Δ X X X ◯ ◯ Δ Cable surface ⊚ ⊚ ⊚ ⊚ ◯ Δ X X X Δ Δ Mechanical characteristics of cable specimens Melt index 63 83 61 47 107 162 40 24 23 49 46 (250° C./10 kg) Tensile strength 251 222 261 247 216 201 238 232 212 174 174 (room-temperature T/S) Elongation 211 207 217 222 177 154 201 187 169 224 146 (room-temperature T/E) Hardness 87 89 88 88 91 93 89 90 90 86 91 Fire Pass Pass Pass Pass Pass Pass Fail Fail Fail Fail Fail retardancy * Extrudability and cable surface: Classified into four steps (⊚, ◯, Δ, X) based on appearance quality and productivity upon cable extrusion. * Properties except for melt index and hardness were measured using cable specimens based on UL 1581. * The additive comprises oil, an antioxidant (A/O), a lubricant, etc.

(5) As shown in Table 1, it can be confirmed that the resin compositions (Examples 1 and 5) according to the present invention have a proper melt index and superior fire retardancy. In addition, it can be confirmed that other mechanical properties such as tensile strength and elongation are superior, and thus, the resin compositions may be particularly useful in preparation of electric wires comprising cables requiring simultaneously both processability and fire retardancy. On the other hand, it can be confirmed that, in Comparative Examples 1 comprising too large amount of the room-temperature liquid-type phosphorus-based fire retardant, hardness and mechanical properties (elongation) are negatively affected. In addition, it can be confirmed that, in Comparative Examples 2 to 4 not comprising the room-temperature liquid-type phosphorus-based fire retardant, cable extrusion characteristics, mechanical characteristics and fire retardancy are all deteriorated. That is, it can be judged that use of the room-temperature liquid-type phosphorus-based fire retardant according to the present invention affects cable processability and surface characteristics, which are related to dispersibility of other solid-phase fire retardants. In addition, it can be judged that the dispersibility is closely related to fire retardancy. On the other hand, it can be confirmed that, in the case of Reference Examples 2 in which, in spite of application of the room-temperature liquid-type phosphorus-based fire retardant, a large amount of melamine polyphosphate as a nitrogen-based fire retardant that is a solid at room-temperature is used, hardness is slightly increased, but extrudability and cable surface characteristics are not good, tensile strength and elongation are negatively affected, and fire retardancy is also deteriorated. In particular, it can be confirmed that, when melamine polyphosphate is used as a nitrogen-based fire retardant being a solid at room-temperature, application of 13% by weight or less of the melamine polyphosphate (based on 19 to 21% by weight in total of fire retardant) leads to stable properties. In addition, it can be confirmed that, in Reference Examples 1 comprising a small amount of the room-temperature liquid-type phosphorus-based fire retardant, exhibition of fire retardancy is limited and a surface of an obtained cable is also not good.

(6) Based on the results, it can be confirmed that, when the fire retardant resin composition according to the present invention comprises the room-temperature liquid-type fire retardant in a proper amount, other mechanical properties are superior with superior fire retardancy and satisfactory extrudability, whereby the fire retardant resin composition is suitable for preparation of a variety of molded products, particularly electric wires comprising cables, requiring fire retardancy.