KR100589510B1 - Flame retardant polypropylene resin composition - Google Patents

Abstract

The present invention relates to a flame retardant polypropylene resin composition, particularly a flame retardant polypropylene resin composition suitable for automotive wire coating, and more particularly, to heat resistance, impact strength, whitening resistance, flame retardancy, and stretchability, which are particularly required for automotive wire coating. Polypropylene with long branches, which is more environmentally friendly than conventional polyvinyl chloride (PVC) resin compositions for automobile wire coating, which satisfies the breaking strength, physical properties, and the like, and has environmental problems. A flame retardant polypropylene resin composition comprising a resin, a polyolefin elastomer, a modified polyolefin, and a non-halogen flame retardant.

Flame Retardant, Polypropylene, Resin, Composition, Automotive, Wire Cover

Description

Flame retardant polypropylene resin composition {FLAME RETARDANT POLYPROPYLENE RESIN COMPOSITION}

The present invention relates to a flame retardant polypropylene resin composition, particularly a flame retardant polypropylene resin composition suitable for automotive wire coating, and more particularly, to heat resistance, impact strength, whitening resistance, flame retardancy, and stretchability, which are particularly required for automotive wire coating. Polypropylene with long branches, which is more environmentally friendly than conventional polyvinyl chloride (PVC) resin compositions for automobile wire coating, which satisfies the breaking strength, physical properties, and the like, and has environmental problems. A flame retardant polypropylene resin composition comprising a resin, a polyolefin elastomer, a modified polyolefin, and a non-halogen flame retardant.

Conventionally, for automotive wire coating, resin compositions such as polyvinyl chloride (PVC), polyethylene (PE, PE) and polybutylene terephthalate (PBT) have been used, and these are required heat resistance. According to the degree, it is classified and used in electronics, doors, trunks, underhoods, engine contact parts, etc. of automobiles.

However, among the conventional resin composition for automotive wire coating, PVC resin composition has an environmental problem that dioxin, heavy metal compounds, etc. are generated when incinerated, PE resin composition has a low melting point, the engine contact required heat resistance of 100 ℃ or more It cannot be used for the portion to the lower hood portion. In addition, the PBT resin composition has a disadvantage in that the heat resistance is excellent but the price is very expensive.

On the other hand, the polypropylene composition has excellent mechanical properties, chemical resistance, etc. for electrical insulation properties and manufacturing convenience, and is widely used as inclusions in electric wires and communication cables. In order to impart flame retardant properties to such polypropylene resin compositions, halogen-based compounds have been mainly used as flame retardants.

However, a product formed of a flame retardant polypropylene composition containing such a halogen-based flame retardant, when exposed to high heat and flames by a fire or the like, generates corrosive and harmful halogen gas and dense smoke to the human body, which is fatal to the human body. It will be adversely affected. In addition, the above hazards occur in the manufacture of the same product, there is a problem that has a very serious adverse effect on the health of workers.

In order to solve the problems caused by the halogen-based flame retardant, a technique using a metal hydroxide or an ammonium sulfate flame retardant as a non-halogen flame retardant has been developed. However, for example, as in JP-A-7-252388, a method of chemically crosslinking or electron beam crosslinking of a non-halogen-based flame retardant composition material based on an ethylene copolymer as a base resin, or having excellent mechanical properties and heat resistance Although the use of polypropylene in basic resins has been studied, it is not satisfactory in terms of the balance of physical properties.

In addition, as in Japanese Patent Laid-Open Nos. 2001-342309, 2003-313377, and 2004-75992, a flame retardant polypropylene composition having a high filling inorganic flame retardant for communication cables, electric wire cables, and automotive electric wire coating applications has been studied. However, they all have a problem in that physical properties such as heat resistance, breaking strength and elongation are inferior because they use general polypropylene having a linear chain molecular structure as a base resin.

The present invention is to solve the problems of the prior art as described above, an object of the present invention, the most suitable for automotive wire coating, in particular has a heat resistance enough to be usable above 100 ℃, whitening resistance, impact resistance, flame resistance The present invention provides a flame retardant polypropylene resin composition that is more excellent in heat resistance, tensile strength, and stretchability than a conventional resin composition including a polypropylene base resin having a molecular structure of a general linear chain while satisfying the above.

According to the present invention, 100 parts by weight of a polypropylene resin having a long branch having a melt index of 0.02 to 4.0 g / 10 minutes at a temperature of 230 ° C. and a load of 2.16 kg, 3 to 15 parts by weight of a polyolefin elastomer, and 2 to 2 parts of a modified polyolefin Provided is a flame retardant polypropylene resin composition comprising 6 parts by weight and 80 to 140 parts by weight of a non-halogen flame retardant.

The polypropylene resin in which the long branch is included in the resin composition of the present invention has a melt index of 0.02 to 4.0 g / 10 minutes, more preferably measured at a temperature of 230 ° C. and a load of 2.16 kg based on ASTM D1238. Is characterized in that 0.04 ~ 2.0g / 10 minutes. If the melt index is less than 0.02 g / 10 minutes, the resin processing characteristics deteriorate, and if it exceeds 4.0 g / 10 minutes, there is a problem that the heat resistance, tensile strength and the like decreases.

In addition, it is particularly preferable that the polypropylene-based resin into which the long branch is introduced has a melt strength of 200 mN or more and a stretch thickening property of shear thickening, in terms of tensile strength and stretchability.

Moreover, as a polypropylene resin in which the said long branch was introduce | transduced, for example, a polypropylene homopolymer or a propylene ethylene copolymer, a propylene-1- butene copolymer, a propylene-1-hexene copolymer, propylene-4-methyl Small amounts of other alpha olefins, such as -1-pentene copolymers, and the like, block copolymers of propylene, random copolymers or mixtures thereof can be used.

Since the resin composition of the present invention specifically includes the polypropylene resin into which the long branch is introduced, even if it contains a high content of non-halogen-based flame retardant, it can have sufficient mechanical properties to be used for wire coating.

The polyolefin elastomer contained in the resin composition of the present invention is used to impart elasticity and flexibility to the resin composition, and the Mooney viscosity (ML1 + 4, 100 ° C) is preferably 5.0 to 40.0, and is 8.0 to 30.0. More preferred. When the pattern viscosity is less than 5.0, the flowability is improved, but the mechanical properties are lowered. When the pattern viscosity is more than 40.0, the mechanical properties are improved, but the flowability is decreased, making molding difficult.

As said polyolefin elastomer, ethylene propylene copolymer rubber, ethylene octene copolymer rubber, ethylene propylene dicyclopentadiene rubber, ethylene propylene-1,4-hexadiene rubber, ethylene propylene cyclopentadiene rubber, ethylene propylene methylene norbornene rubber , Ethylene propylene ethylidene norbornene rubber, ethylene butadiene copolymer rubber or ethylene octadiene copolymer rubber are preferably used, in particular ethylene propylene copolymer rubber or ethylene octene copolymer rubber is preferably used. In addition, a thermoplastic elastomer resin, hydrogenated styrene-butadiene block copolymer (SEBS), hydrogenated styrene butadiene rubber (HSBR), styrene-ethylene-butylene block copolymer (SEBC) or crystalline ethylene-butylene block copolymer ( CEBC) etc. can also be used. When using the thermoplastic elastomer resin, the impact resistance can be particularly improved. Moreover, in the said polyolefin elastic body, it is preferable that content of a comonomer is 10-40 weight%, especially 20-30 weight%, since an elasticity can be improved without impairing the processability of a resin composition.

In the resin composition of this invention, it is preferable that 3-15 weight part of said polyolefin elastic bodies are contained with respect to 100 weight part of polypropylene resin into which the said long branch was introduce | transduced. When this content is less than 3 weight part, When elasticity, stretchability, etc. fall and workability worsens, when it exceeds 15 weight part, flowability will fall and molding will become difficult.

The modified polyolefin included in the resin composition of the present invention is used to improve heat resistance through improved adhesion to the non-halogen flame retardant interface of the resin composition.

As the modified polyolefin, a modified polypropylene resin grafted with an unsaturated carboxylic acid or an anhydride thereof, a grafted modified polyethylene resin, or a grafted modified polybutylene resin can be preferably used, and the production of such modified polyolefin resin Can be carried out by a conventional melt kneading method, for example, it can be produced by adding crystalline polypropylene and unsaturated carboxylic acid or its anhydride and catalyst to a twin screw extruder and heat melting at a temperature of 180 ~ 220 ℃.

In the resin composition of the present invention, the modified polyolefin is preferably contained in an amount of 2 to 6 parts by weight based on 100 parts by weight of the polypropylene resin into which the long branch is introduced. The adhesiveness of a flame retardant and a polypropylene resin falls and the flame retardance and heat resistance of a resin composition worsen, and when it exceeds 6 weight part, workability and mechanical properties will worsen.

The non-halogen-based flame retardant contained in the resin composition of the present invention, does not include a halogen as a superior flame retardant than in the environmentally friendly point of view, it is used to improve the heat resistance and flame retardancy, magnesium hydroxide (Mg (OH) _2), hydroxide Metal hydroxides such as aluminum (Al (OH) ₃ ), calcium hydroxide (Ca (OH) ₂ ) and the like are particularly preferably used.

In the resin composition of the present invention, the non-halogen-based flame retardant is preferably contained in a relatively high content of 80 to 140 parts by weight relative to 100 parts by weight of the polypropylene resin into which the long branch is introduced. When the said content is less than 80 weight part, sufficient flame retardance cannot be provided to a resin composition, and when it exceeds 140 weight part, workability and mechanical property will fall remarkably.

As in the present invention, in the case of using a non-halogen-based flame retardant such as a metal hydroxide to replace the conventional halogen-based flame retardant, which is environmentally problematic, in order to obtain sufficient flame retardancy, the non-halogen-based flame retardant is contained in a relatively high content of the resin composition. Although it is necessary to include it in the conventional polypropylene resin composition, when the non-halogen flame retardant is included in a high content, mechanical properties such as breakage or brittleness in the drawing process for cable forming are easily degraded. There is a problem that the workability is poor. However, according to the present invention, by adding 3 to 15 parts by weight of the polyolefin elastomer to the polypropylene resin composition and 2 to 6 parts by weight of the modified polyolefin, non-halogen flame retardants, in particular, metal hydroxide up to 140 parts by weight Even when included in a high content up to, it is possible to obtain a polypropylene resin composition having maximized flame retardance without deteriorating mechanical properties and workability.

In addition to the above components, the flame retardant polypropylene resin composition of the present invention further includes other additives generally added to flame retardant compositions for wire coating such as antioxidants, lubricants, and the like within the scope of achieving the object of the present invention. can do. Among these other additives, in particular, it is preferable to further add 0.1 to 1 part of the antioxidant and 0.5 to 2.5 parts by weight of the lubricant with respect to 100 parts by weight of the polypropylene resin in view of workability and physical properties.

The flame retardant polypropylene resin composition of the present invention may be prepared according to a conventional resin composition production method, that is, for example, the flame retardant polypropylene resin composition of the present invention may be a polypropylene resin alone or a mixture thereof, non-halogen-based. As a flame retardant, magnesium hydroxide (Mg (OH) ₂ ), a polyolefin elastomer, a modified polyolefin, an antioxidant, and a lubricant, which are metal hydroxides, are added to the mixing apparatus at the above-described content ratios, which are mixed by stirring for 1 minute to 1 hour. , And melted and kneaded at a temperature of 200 to 250 ° C. using a rolling mill or an extruder to obtain a resin composition in pelletized form.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Examples 1-3 and Comparative Examples 1-3

For each example and comparative example, the raw materials as shown in Table 1 were added to a Hensel mixer (trade name) in an amount as shown in Table 1 below, followed by stirring for about 3 minutes to mix. The resulting mixture was melt-extruded at about 200 ° C. using a single screw extruder with a diameter of 30 mm to prepare a flame retardant resin composition in pelletized form.

For each Example and Comparative Example, after fabricating the specimen using the prepared flame-retardant resin composition, the heat resistance, wire whitening phenomenon, room temperature IZOD impact strength, room temperature breaking strength, room temperature elongation and flame retardancy were evaluated or measured and the results It is shown in Table 2 below. The physical property measurement method used in the present Example and the comparative example is as follows.

[Measurement of physical properties]

① Melt index (MI): measured at 230 ° C and 2.16 kg based on ASTM D1238.

(2) Melt strength and elongation viscosity characteristics: Using a SMER (Samsung Melt Tension Rheometer) described in Korean Utility Model Application No. 1999-0008553 and Korean Patent Application No. 2001-0030112, the use of a capillary rheometer at 200 ° C. Measured at 140 ° C. chamber temperature for the strand exiting the die.

③ Heat resistance: The cracks on the coating surface were visually observed after heating for more than 60 hours, 120 hours, 240 hours, 360 hours, and 480 hours in an oven at 150 ° C, and evaluated based on the time required when the cracks were found.

④ Wire whitening phenomenon: Bending 180 ° on the specimen formed by wire coating, and visualizing the whitening at the bent part.

⑤ Room temperature IZOD impact strength: Measured on injection specimens with a thickness of 3.2mm based on ASTM D256.

⑥ Breaking strength and elongation at room temperature: Measure the strength and elongation at break under 50mm / min of tensile speed by using 2mm thick injection test specimen according to ASTM D-412.

⑦ Flame retardancy: measured on a specimen of 1.6 mm thickness in accordance with UL94.

Table 1 Compositions of the resin compositions of Examples 1 to 3 and Comparative Examples 1 to 3 (unit: parts by weight)

PP-1 PP-2 POE MPO FR-1 FR-2 AO LB Example 1 100 - 9 4 110 - 0.2 1.5 Example 2 100 - 15 6 140 - 0.2 1.5 Example 3 100 - 3 2 80 - 0.2 1.5 Comparative Example 1 - 100 9 4 110 - 0.2 1.5 Comparative Example 2 100 - 9 4 - 50 0.2 1.5 Comparative Example 3 100 - 2 One 40 - 0.2 1.5

PP-1: Homopolypropylene with long branches (GRADE HM200F, Samsung Total Co., Ltd.), melt index 1.7g / 10min, melt strength 200mN, shear thickening characteristic

PP-2: Homopolypropylene with linear structure (GRADE HF11HPT1, Samsung Total Co., Ltd.), melt index 1.6g / 10min, melt strength 30mN, shear thinning elongation viscosity characteristics

POE: Polyolefin elastomer (ethylene propylene copolymer rubber, GRADE VISTAMAXX VM1100, ExxonMobil Corporation), Mooney viscosity (ML1 + 4, 125 ° C) 25

MPO: Modified Polyolefin (Modified Polypropylene, GRADE CP4673, Samsung Total Co., Ltd.)

FR-1: Non-halogen flame retardant (magnesium hydroxide (Mg (OH) ₂ )

FR-2: Halogen Flame Retardant

(Bispentabromophenoxytane, S-8010, Albermale USA)

AO: Antioxidant (IRGANOX 1010, Ciba Geiza)

LB: Lubricant (Songstab SC-110, Songwon Industry)

TABLE 2

Heat resistance (time required to crack) Wire whitening phenomenon IZOD impact strength at room temperature (kgcm / cm) Room temperature breaking strength (kg / ㎠) Room Temperature Elongation (%) Flame Retardant (UL94 Rating) Example 1 After 360 hours none 6.3 327 375 V-0 Example 2 After 360 hours none 7.0 350 343 V-0 Example 3 After 360 hours none 6.1 303 392 V-1 Comparative Example 1 120 hours later none 6.0 164 154 V-0 Comparative Example 2 After 360 hours has exist 6.3 311 367 V-0 Comparative Example 3 After 240 hours none 5.1 289 352 V-2

According to the results shown in Table 2, Example 1 using homopolypropylene having a long branch introduced into the molecular structure is similar to Comparative Example 1 using homopolypropylene having a linear structure in terms of whitening resistance, impact strength and flame retardancy. It can be seen that the heat resistance is more than three times, and the room temperature breaking strength and elongation are about two times or more.

In addition, in Example 2, the resin composition excellent in all the physical properties of Table 2 was obtained, although the metal hydroxide flame retardant was added at a high content of 140 parts by weight, and in Example 3, the content of the polyolefin elastomer and the modified polyolefin was Even if it is reduced to 3 parts by weight and 2 parts by weight, respectively, it was possible to add a metal hydroxide flame retardant to the content of 80 parts by weight, as a result, although the flame retardancy is somewhat reduced, it was also possible to obtain a resin composition excellent in various physical properties.

On the other hand, when comparing the Comparative Example 2 and the examples using a halogen-based flame retardant, the resin composition of the examples were excellent in whitening resistance, and showed the same level for the other physical properties, thereby adversely affecting the environment It can be seen that an environmentally friendly polypropylene resin composition having a flame retardancy and physical properties similar to or better than those of a conventional flame retardant resin composition has been obtained without using a halogen-based flame retardant.

On the other hand, in the case of Comparative Example 3, as a result of reducing the content of the polyolefin elastomer and the modified polyolefin to 2 parts by weight and 1 part by weight, as compared with Example 3, it was inevitable to add a metal hydroxide flame retardant to a maximum content of 40 parts by weight, Although not shown in this example, in Comparative Example 3, when the metal hydroxide flame retardant was added in a higher content, the processability of the resulting resin composition was so bad that significant preparation and measurement of physical properties were impossible. As a result, the resin composition of the comparative example 3 was inferior compared with the resin composition of the Example especially in flame retardance. From this, in order to obtain the desired level of flame retardancy of the present invention, a metal hydroxide flame retardant must be added at a predetermined level or higher, and for this purpose, the content of the polyolefin elastomer and the modified polyolefin is at least 3 parts by weight and 2 parts by weight or more, respectively. It was found that it should be added to the composition.

As described above, according to the present invention, flame retardancy having a similar level of whitening resistance, impact resistance, flame retardancy, and the like to conventional flame retardant polypropylene compositions having a general linear molecular structure, and having superior heat resistance, breaking strength, room temperature elongation, and the like. Polypropylene compositions can be obtained. Therefore, the flame-retardant resin composition according to the present invention can be suitably used for the communication cable and electrical and electronic wire coating, automotive wire coating and the like that require heat resistance of more than 100 ℃, in particular can be used for automotive wire coating have. In addition, since the flame-retardant polypropylene resin composition according to the present invention greatly strengthens the breaking strength and the stretchability, which are mechanical properties, the workability is greatly improved and productivity can be increased.

In addition, since the flame retardant polypropylene resin composition according to the present invention uses an environmentally friendly polypropylene material and a non-halogen flame retardant, the environment is superior to the flame retardant resin composition using a conventional polyvinyl chloride material and / or a halogen flame retardant. Has affinity.

Claims (6)

100 parts by weight of a polypropylene resin with a long branch having a melt index of 0.02 to 4.0 g / 10 minutes at a temperature of 230 ° C. and a load of 2.16 kg, 3 to 15 parts by weight of a polyolefin elastomer, 2 to 6 parts by weight of a modified polyolefin, and a ratio Flame-retardant polypropylene resin composition comprising 80 to 140 parts by weight of a halogen-based flame retardant. The flame retardant polypropylene resin composition according to claim 1, wherein the polypropylene-based resin into which the long branch is introduced has a melt strength of 200 mN or more, and has a draw viscosity concentrated by shear concentration. The flame retardant polypropylene resin composition according to claim 1, wherein the polypropylene resin into which the long branch is introduced is a polypropylene homopolymer, a propylene block copolymer, a propylene random copolymer, or a mixture thereof. The flame retardant polypropylene resin composition according to claim 1, wherein the polyolefin elastomer is an ethylene propylene copolymer rubber or an ethylene octene copolymer rubber. The flame retardant polypropylene resin composition of claim 1, wherein the non-halogen flame retardant is a metal hydroxide. The flame retardant polypropylene resin composition according to claim 1, further comprising 0.1 to 1 middle part of the antioxidant and 0.5 to 2.5 parts by weight of the lubricant with respect to 100 parts by weight of the polypropylene resin into which the long branch is introduced.