KR19980025935A - Flame Retardant Low Flame Thermoplastic Composition - Google Patents

Abstract

The present invention relates to a flame retardant low-flammability thermoplastic resin composition, and more particularly, (1) 25 to 70% by weight of a polyolefin resin having a Tm (melting point) of 125 ° C or higher, and (2) grafted with an unsaturated carboxylic acid or a derivative thereof. Polyolefin resin compatibilizer 5-30% by weight, and (3) 25-70% by weight of a monomer or derivative thereof having a carboxyl group and a copolymer of ethylene, a mixture of the above components (1), (2) and (3) 100 parts by weight of phosphorus polymer resin, (4) 1 to 20 parts by weight of organic polysiloxane, and (5) 25 to 150 parts by weight of inorganic flame retardant, which is a metal compound coated with saturated fatty acid or fatty acid ester and free of hydroxyl group or hydrate. It relates to a flame-retardant low-flame thermoplastic resin composition consisting of.

Description

Flame Retardant Low Flame Thermoplastic Composition

The present invention relates to a flame retardant low flame retardant thermoplastic resin composition, and more particularly, to a flame retardant low flame retardant thermoplastic polyolefin resin composition for coating a communication power cable.

In general, flame retardant polyolefin resins have been commonly used in combination with an organic halogen flame retardant and antimony trioxide. In the case of using an organic halogen flame retardant, a relatively small amount of high flame retardancy can be provided. There is a problem that generates a large amount of smoke generation toxic and highly corrosive halogen gas.

In addition, in the case of a flame retardant thermoplastic composition that does not include an organohalogen compound, since a large amount of inorganic flame retardants must be blended in an amount of 100 parts by weight or more with respect to the base resin in order to increase the flame retardancy, there is a problem of greatly reducing workability and mechanical properties. In order to compensate for this problem, by adding a small amount of red phosphorus, it was possible to improve the physical properties by reducing the content of the inorganic flame retardant while maintaining the flame retardancy, but still shows insufficient characteristics in reducing the amount of smoke.

In addition, in order to improve this problem, a technique using an organophosphorus flame retardant has been developed and used as a flame retardant resin composition. However, such a mixture is expensive, has a high risk of generating toxic and corrosive compounds in the event of a fire, and absorbs and handles moisture. It has a hard disadvantage.

In addition, in order to impart flame retardancy, low toxicity and low flammability, silicone oil, silicone gum, silicone resin and the like have been used in the flame retardant resin composition. U.S. Patent No. 4,430,470 discloses a composition in which ethylene vinyl acetate (EVA) or ethylene ethyl acrylate (EEA) resin is blended with aluminum hydroxide and 0.05 to 2.0% by weight of methyl hydrogen polysiloxane based on aluminum hydroxide. have. In addition, U.S. Patent No. 4,731,406 describes the fact that the amount of smoke during ignition is greatly reduced by combining ethylene propylene diene polymer (EPDM) rubber with magnesium hydroxide or aluminum hydroxide inorganic flame retardant together with silicone gum containing acrylic rubber and unsaturated groups. . U.S. Patent No. 5,091,453 discloses at least 40% of copolymers of ethylene with at least one comonomer consisting of (A) alkyl acrylates, alkyl methacrylates, acrylic acid, methacrylic acid and vinyl acetate, and (B) silicone oil or A flame retardant resin composition composed of an inorganic filler (magnesium oxide, magnesium carbonate, calcium carbonate, etc.) composed of a metal compound belonging to the group IIA in the periodic table other than silicon gum and (C) hydroxide or hydrate is described. The compositions mentioned in the above patents have significantly improved smoke characteristics compared to conventional flame retardant compositions. However, since the polymer having a low melting point (less than 100 ° C.) is used as the base resin, the heat deformation properties and heat resistance of more than 100 ° C. are limited. I have a problem.

Accordingly, an object of the present invention is to provide a thermoplastic resin composition which can be used for coating communication and power cables, which has greatly improved flame retardancy as well as low flame resistance and heat deformation.

The composition of the present invention for achieving the above object is (1) 25 to 70% by weight of a polyolefin resin having a Tm (melting point) of 125 ° C or more, (2) polyolefin resin compatibilizer grafted with unsaturated carboxylic acid or derivatives thereof 5 to 30% by weight, and (3) 25 to 70% by weight of a monomer having a carboxyl group or a derivative thereof and a copolymer of ethylene, a mixture of the components (1), (2) and (3) (hereinafter referred to as polymer resin) ), Based on 100 parts by weight, (4) 1 to 20 parts by weight of organopolysiloxane, and (5) 25 to 150 parts by weight of an inorganic flame retardant which is coated with saturated fatty acid or fatty acid ester and is a metal compound without hydroxyl group or hydrate. .

The composition may further include an antioxidant, a sunscreen, a processing aid, silica, a colorant, a metal deactivator, a crosslinking agent, a foaming agent and / or carbon black in addition to the above components.

Hereinafter, the present invention will be described in detail.

In the present invention, the polyolefin resin that can be used as the base resin of the flame retardant composition for the purpose of increasing mechanical properties, heat resistance and heat deformation properties, the melting temperature (Tm) is 125 ℃ or more, the melt index (MI) is 0.1 It can be used one or more selected from the group consisting of polypropylene resin, linear low density polyethylene, medium density polyethylene, and high density polyethylene resin that is from 5g / 10 minutes, preferably polypropylene or high density polyethylene resin. The amount of the polyolefin resin is preferably 25 to 70% by weight, but less than 25% by weight, the heat deformation and heat resistance properties are lowered, and when the amount exceeds 70% by weight, the amount of smoke is increased, flame retardancy and flexibility is inferior.

The polyolefin resin compatibilizer used in the present invention is a composition grafted by adding 0.5 to 3% by weight of an unsaturated carboxylic acid or a derivative thereof to a polyolefin resin in the presence of an organic peroxide, or a grafted composition and a polyolefin resin, Is a mixture of. As the polyolefin resin, a copolymer of ethylene and α-olefin, a high density polyethylene, a polypropylene homopolymer, ethylene vinyl acetate, and / or a copolymer of ethylene and octene-1 using a metallocene catalyst may be used. The following are copolymers of ethylene and α-olefin, copolymers of ethylene and octene-1 using a high density polyethylene or metallocene catalyst, and the like. In addition, as the unsaturated carboxylic acid or derivatives thereof, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, and the like may be used, and maleic anhydride is particularly preferable. In the case of the grafted polyolefin resin used in the present invention, the amount of the grafted carboxyl group is preferably 0.1 to 1.0% by weight based on 100% by weight of the polyolefin resin, the amount of the grafted polyolefin resin compatibilizer is The range of 5-30 weight% is preferable. When the amount of the compatibilizer is less than 5% by weight, it is difficult to develop a compatibility effect with the polyolefin resin, the ethylene copolymer, and the inorganic flame retardant, which are the polymer components, and it is difficult to increase the tensile strength. In addition, when the amount of the compatibilizer exceeds 30% by weight, the decrease in extrusion processability due to the strong adhesion with the flame retardant composition, in particular, the decrease in elongation is remarkable.

The ethylene copolymer used in the present invention is a copolymer of ethylene and a monomer having a carboxyl group or a derivative thereof. For example, ethylene vinyl acetate (EVA), ethylene ethyl acrylate (EEA), ethylene methyl acrylate ( EMA), ethylene butyl acrylate (EBA), ethylene methyl methacrylate (EMMA), ethylene glycidyl methacrylate (EGMA), ethylene acrylic acid (EAA), or ethylene methacrylic acid copolymer (EMAA), and the like. Or mixed and used, preferably ethylene ethyl acrylate, ethylene methyl acrylate or ethylene vinyl acetate. The content of the carboxyl group of the ethylene copolymer is preferably in the range of 5 to 25% by weight, more preferably 10 to 20% by weight. When the content of the carboxyl group is less than 5% by weight, when mixed with the polyolefin resin and the inorganic flame retardant, the flexibility is difficult and the filling of the inorganic flame retardant is difficult, the mechanical strength is lowered, when the content of the carboxyl group exceeds 25% by weight polyolefin The compatibility with the resin is disadvantageous in that the extrusion appearance characteristics are lowered. As for the range of MI of the said ethylene copolymer, 0.1-10 g / 10 component is preferable, More preferably, it is 0.3-5 g / 10 component. When blending the polyolefin resin and the compatibilizer and the ethylene copolymer, the content of the ethylene copolymer should not exceed 70% by weight, and when the ethylene copolymer is used in excess of 70% by weight, the heat deformation and heat resistance characteristics are greatly reduced. Efficient compositions cannot be obtained. On the other hand, if the content of the ethylene copolymer is less than 25% by weight, there is a disadvantage that the flame retardancy is poor and the smoke generation amount is large. Therefore, the ethylene copolymer is preferably used in the range of 25 to 70% by weight.

The organopolysiloxane which can be used in the present invention is composed of one or more organosiloxane units having a methyl (Me), phenyl (Ph) or vinyl (Vi) group as silicone oil, gum, resin, etc. and represented by the following formula: Me ₂ SiO; Ph ₂ SiO; MePhSiO; MeViSiO; MeSiO _1.5 ; PhSiO _1.5 ; ViSiO _1.5 ; Me ₃ SiO _0.5 ; MePh ₂ SiO _0.5 and Me ₂ ViSiO _0.5 . Preferably, the organic polysiloxane is polydimethylsiloxane, polymethylvinylsiloxane or polymethylphenylvinylsiloxane, and has a viscosity in the range of 1,000 to 1,000,000 cSt at 25 ° C. If the viscosity range is less than 1,000 cSt, the extrusion appearance is uneven, and if it exceeds 1,000,000 cSt, the viscosity is high, so handling is difficult. In addition, the content of the organic polysiloxane is 1 to 20 parts by weight based on 100 parts by weight of the polymer resin, more preferably in the range of 3 to 10 parts by weight. When the organic polysiloxane is less than 1 part by weight or more than 20 parts by weight, there is a disadvantage in that each of the flame retardancy or the extrusion appearance deteriorates during extrusion of the flame retardant composition.

Inorganic flame retardants that can be used in the present invention include, for example, magnesium oxide, magnesium carbonate, calcium oxide, calcium carbonate, barium carbonate, zinc carbonate, molybdenum oxide or zirconium oxide, and the like, and may be used alone or in combination. Calcium carbonate is more preferable among the components, and the surface should be coated with saturated fatty acid or fatty acid ester to improve flame retardant dispersion and processability. According to the present invention, the inorganic flame retardant may be used in an amount of 10 to 300 parts by weight based on 100 parts by weight of the polymer resin, but in consideration of mechanical properties and flame retardancy, it is preferably 25 to 150 parts by weight. The particle size of the inorganic flame retardant varies depending on the type of flame retardant, but in the case of calcium carbonate, the average particle size is 20 µm or less, and more preferably 0.5 to 3 µm. In addition, the present invention may additionally be used together as an additional flame retardant.

In addition, an antioxidant, a sunscreen, a processing aid, silica, a colorant, a metal activator, a crosslinking agent, a foaming agent, and / or carbon black may be further added to the composition.

The flame-retardant composition of the present invention is a polymer resin, organic polysiloxane, inorganic flame retardant and other additives in the range of 160 ~ 250 ℃ that is soft enough to melt the organic polymer in a conventional Banbury mixer, kneader, 2-roll mill or twin screw extruder And the like can be mixed together, and the final form of the flame retardant composition is obtained in pellet form. The flame retardant composition obtained by the method can be extruded into a sheath of communication and power cables.

According to the present invention, the prepared flame retardant composition exhibited a characteristic that the smoke generation amount was reduced to 30% or less compared with the flame retardant composition using a conventional hydroxyl group or a hydrate type flame retardant.

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

The resin components and physical property measurement methods used in the following Tables 1, 2 and 3 are as follows.

·ingredient

1A: polyolefin resin, HDPE, Yugong Co., Ltd .; Product name MD800 (density = 0.955 g / cm ³ , MI = 1.0 / 10 min, Tm = 135 ° C.)

2A: compatibilizer, Yugong Corporation; POLYGLUE LE400T (Linear low density polyethylene resin grafted with maleic anhydride, MI = 4.5 g / 10 min, density = 0.925 g / cm ³ )

3A: EVA, Hanwha General Chemical Co., Ltd .; EVA 1315 (density = 0.935g / cm ³ , MI = 1.5g / 10min, VA = 10%)

3B: EEA, Mitsui-Dupont Corporation; Product name EEA A703 (MI = 5g / 10min, EA = 25%)

3C: EEA, Japanese Petrochemical Company; Product name EEA 1100 (MI = 0.4g / 10min, EA = 10%)

3D: EMA, Exxon company; TC-110 (MI = 2.0g / 10min, MA = 20%)

4A: silicone oil, Toshiba Corporation; TSF 451-1M (viscosity at 25 ° C = 10,000cSt, dimethylsiloxane)

4B: silicon compound, Lucky-DC silicon; Product name GP-130 (polymethylvinyl siloxane)

5A: CaCO ₃ , Dong Hwa Mining Co., Ltd .; Product name SST-40 (average particle size = 1.1μ, coated with higher fatty acids)

5B: CaCO ₃ , Cheil Industries Co., Ltd .; Product name C / SP (Average particle size = 1.48μ, uncoated)

5C: Mg (OH) ₂ , Kyowa Chemical Industry Co .; Formerly KISMA 5B

Antioxidants: Ciba-Geigy Co .; Formerly Irg-1010

Property test method

(1) Tensile properties: tensile strength (kg / cm2) (denoted as TS as maximum tensile strength), elongation (%) (denoted by UEL); According to ASTM D412, a dumbbell specimen having a thickness of 2 mm was manufactured and measured at 200 mm / min.

(2) Heating characteristics: Tensile strength and elongation were measured after heat treatment for 121 ° C. and 168 hours according to ASTM D412.

(3) Heat strain: Heat strain was measured after 30 minutes of heat treatment at 120 ° C. for 30 minutes in accordance with ASTM D2308.

(4) Smoke density: 3.2mm test piece according to ASTM E662, measured by Non-Flamming method.

(5) Flame retardancy (oxygen index): measured according to ASTM D2863.

(6) Extrusion processability: Extrusion test was carried out in a single screw extruder having a barrel diameter of 19 mmΦ and L / D = 24.

-Die Type = Tube Die with 9mm Inner Diameter and 1mm Thickness

Temperature condition = 175-200-205 ℃

Screw (rpm) = 80

[Examples 1-5]

The high density polyethylene and ethylene ethyl acrylate copolymer were blended in the ratios shown in Table 1 below, kneaded together with a compatibilizer, a silicone oil, an inorganic flame retardant and an antioxidant in a Banbury mixer for about 10 minutes, and then pelletized through a single screw extruder. To prepare, and measured the flame retardancy, including the tensile properties, the results are shown in Table 1 below.

[Comparative Examples 1 and 2]

Tensile polyethylene and ethylene ethyl acrylate copolymers were prepared by mixing and preparing a compatibilizer, a silicone oil, an inorganic flame retardant, and an antioxidant in the same amount as in Example 1 to measure tensile properties and flame retardancy, and the results are shown in Table 1 below. Indicated.

Comparative Example 3

An inorganic flame retardant was prepared in the same manner as in Example 2, except that 100 parts by weight of magnesium hydroxide having a hydroxyl group, which is commonly used in inorganic flame retardants, was measured, and tensile properties and flame retardancy were measured. It is shown in Table 1 below.

[Comparative Example 4]

100 parts by weight of the organic polymer was prepared in the same manner as in Example 2, except that 30 parts by weight of silicon compound instead of silicon oil, tensile properties and flame retardancy and the like are shown in Table 1 below.

[Comparative Example 5]

Calcium carbonate was carried out in the same manner as in Example 2 except that the surface-coated product was not used, and the results are shown in Table 1 below.

TABLE 1

1) is silicone compound, 2) is not measurable

EXAMPLES 6-8

The compatibilizer was mixed with the high density polyethylene and the ethylene methyl acrylate copolymer in the ratios shown in Table 2 below and kneaded together with the silicone oil, the inorganic flame retardant and the antioxidant in a Benbury mixer for about 10 minutes, and then pelletized through a single screw extruder. After the preparation, the flame resistance including the tensile properties were measured, and the results are shown in Table 2 below.

[Comparative Examples 6 and 7]

Except that the compatibilizer was not mixed (Comparative Example 6) and only 40 parts by weight of the compatibilizer without the polyolefin resin was added in the same manner as in Examples 6 to 8, the results are shown in Table 2 below.

[Table 2]

1) Silicon Compound

Examples 9-12

Different kinds of ethylene copolymers were blended in the ratios shown in Table 3 below, kneaded in a Banbury mixer, and then pelletized through a single screw extruder to measure the tensile properties and flame retardancy. 3 is shown.

[Examples 13-15]

Except for adding 10 parts by weight of the silicone compound and 100, 80, and 100 parts by weight of the silicone compound with respect to 100 parts by weight of the polymer resin was carried out in the same manner as in Example 11, the results are shown in Table 3 below. Indicated.

Table 3

1) Silicon Compound

When the flame retardant composition was prepared using the high density polyethylene or the ethylene ethyl acrylate copolymer alone from Examples 1 to 5 and Comparative Examples 1 and 2, the flame retardancy was rapidly decreased or the heating characteristics could not be measured. It was found that the thermal deformation occurred, and from Examples 2 and 3, by using the inorganic flame retardant as calcium carbonate can not only reduce the addition amount of the flame retardant, but also improve the flame retardancy and lower the smoke generation amount to 30% or less. I could see that. In addition, when the organic polysiloxane content exceeded 30 parts by weight according to Example 2, and Comparative Examples 4 and 5, the physical properties were lowered and the appearance characteristics during extrusion decreased, and when the calcium carbonate not coated with saturated fatty acid was used as the flame retardant, It was found that the low flame retardancy was inferior to the flame retardant composition according to the present invention.

In addition, from Examples 6 to 8 and Comparative Examples 6 and 7, when the compatibilizer is not added, it is difficult to expect the improvement of physical properties, and when added in excess, the extrudability is increased due to the strong coupling effect with the inorganic flame retardant. It was found that the degradation.

Claims (11)

(1) 25 to 70% by weight of polyolefin resin having a Tm (melting point) of 125 ° C or higher, (2) 5 to 30% by weight of polyolefin resin compatibilizer grafted with unsaturated carboxylic acid or derivatives thereof, and (3) carboxyl group (4) organopolysiloxane 1 to 1 to 25 to 70% by weight of a monomer having a monomer or a derivative thereof and a copolymer of ethylene and a polymer resin which is a mixture of the components (1), (2) and (3). 20 parts by weight, and (5) a flame retardant low-flammability thermoplastic resin composition, consisting essentially of 25 to 150 parts by weight of an inorganic flame retardant, which is coated with saturated fatty acid or fatty acid ester and is a metal compound without hydroxyl group or hydrate. The flame retardant low smoke of claim 1, wherein the polyolefin resin is selected from the group consisting of polypropylene resin, linear low density polyethylene, medium density polyethylene, and high density polyethylene resin having a melt index of 0.1 to 5 g / 10 minutes. Thermoplastic resin composition. The flame retardant low-flammability thermoplastic resin composition according to claim 1, wherein the unsaturated carboxylic acid or derivative thereof is acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, or maleic anhydride. The flame retardant low-flammability thermoplastic resin composition according to claim 1, wherein the polyolefin resin compatibilizer grafted with an unsaturated carboxylic acid or a derivative thereof is a linear low density polyethylene grafted with 0.1 to 1.0% by weight of maleic anhydride. The method of claim 4, wherein the polyolefin resin is a copolymer of ethylene and α-olefin, a high density polyethylene, polypropylene homopolymer, ethylene vinyl acetate, and / or a copolymer of ethylene and octene-1 using a metallocene catalyst. A flame retardant low flame retardant thermoplastic resin composition. The method of claim 1, wherein the copolymer having a carboxyl group or a derivative thereof and ethylene is ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate, ethylene butyl acrylate, ethylene methyl methacrylate, ethylene glycol A flame retardant low flame retardant thermoplastic resin composition, characterized in that at least one selected from the group consisting of cydyl methacrylate, ethylene acrylic acid, and ethylene methacrylic acid copolymer. The method of claim 6, wherein the melt index of the ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer or ethylene methyl acrylate copolymer is in the range of 0.1 to 10 g / 10 minutes, vinyl acetate, ethyl acrylate or methyl acrylic Flame retardant low-flammability thermoplastic resin composition, characterized in that the rate of the range of 5 to 25% by weight. The flame retardant low-flammability thermoplastic resin composition according to claim 1, wherein the organic polysiloxane is polydimethylsiloxane, polymethylvinylsiloxane or polymethylphenylvinylsiloxane. The flame-retardant low-flammability thermoplastic resin composition according to claim 1 or 8, wherein the organic polysiloxane has a viscosity in the range of 1,000 to 1,000,000 cSt at 25 ° C. The inorganic flame retardant according to claim 1, wherein the inorganic flame retardant is one or more selected from the group consisting of magnesium oxide, magnesium carbonate, calcium oxide, calcium carbonate, barium carbonate, zinc carbonate, molybdenum oxide or zirconium oxide, the surface of which is coated with a saturated fatty acid or fatty acid ester. Flame-retardant low-flammability thermoplastic resin composition, characterized in that selected above. The flame retardant low-flammability thermoplastic resin composition according to claim 1, wherein the composition further comprises an antioxidant, a sunscreen, a processing aid, silica, a colorant, a metal deactivator, a crosslinking agent, a blowing agent, and / or carbon black.