KR20000019227A - Polymer composition for electric wire - Google Patents

Abstract

PURPOSE: A polymer composition for electric wire is provided for preventing the declination of the mechanic properties such as tensile strength and elongation and improving the flame retardation. CONSTITUTION: The polymer composition comprises: 70-97 parts by weight of a matrix comprising one to four thermoplastic polyolefin matrix resins; 3-30 parts by weight of an ionomer where metal ions are linked to the backbone of ethylene polymer by substitution; 50-180 parts by weight of an inorganic flame-resistant material; 1-40 parts by weight of a promoter for flame retardation; 0.5-5 parts by weight of a low molecular weight coupling agent; and 0.5-6 parts by weight of an antioxidant. The polyolefin matrix resin is HDPE (high density polyethylene), MDPE (medium density polyethylene), LDPE (low density polyethylene), LLDPE (linear low density polyethylene), ethylene-vinyl acetate, ethylene-ethyl acrylate, ethylene-methyl acrylate or ethylene-acrylic acid. The inorganic flame-resistant material is aluminum hydroxide, magnesium hydroxide, calcium carbonate or magnesium carbonate which is surface-coated with a saturated or unsaturated aliphatic acid such as stearic acid and oleic acid or a binder such as vinyltrimethoxysilane, vinyltriepoxysilane and titanate.

Description

Polymer composition for electric wire

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer coating material for electric wire, and particularly to a flame retardant material composition which can prevent the deterioration of mechanical properties due to the addition of a flame retardant in polyolefin-based non-toxic (halogen-free) flame retardant materials and thereby improve flame retardancy. It is about.

In general, in order to impart flame retardancy to thermoplastic non-toxic flame retardant compositions using polyolefin-based polymers (PE, EVA, EEA, EMA, EBA, etc.), halogen-free flame retardants are added to the polymer, but the mechanical properties of the composition Due to the deterioration of physical properties, there was a limit in increasing the amount added.

That is, in the flame retardant composition used for the coating of the electric wire, a halogen-free flame retardant is added to the polymer in order to impart flame retardancy during combustion and to prevent emission of toxic gases including smoke and halogen elements. .

The type of flame retardant added at this time is usually used by mixing one or more of inorganic flame retardants such as hydroxides or phosphorus-based flame retardants of metals such as magnesium hydroxide and aluminum hydroxide. The flame retardancy of the composition changes depending on the type of flame retardant added and also tends to increase in proportion to the amount added.

On the other hand, mechanical properties of the flame retardant composition, that is, tensile strength and elongation, are reduced as the amount of flame retardant is increased.

That is, the mechanical properties of the flame retardant composition are greatly influenced by the dispersion state of the inorganic flame retardant added to the matrix resin, and the inorganic flame retardant surface-treated with a material that can improve the bonding state with the matrix resin is usually improved to improve dispersibility. Use

In parallel with this, a low molecular weight binder (Coupling agent) may be added to physically bond the matrix resin and the inorganic flame retardant to improve the dispersibility of the inorganic flame retardant and the mechanical properties of the flame retardant composition.

However, even with such a method, it is difficult to avoid the mechanical property degradation of the composition that occurs when a large amount of inorganic flame retardant is added to increase the flame retardancy.

Therefore, the inorganic flame retardant should be selected and controlled in consideration of the mechanical properties of the composition in combination with the flame retardancy in the thermoplastic polymer flame retardant composition.

In the present invention to solve this problem, in the thermoplastic polyolefin-based nontoxic flame retardant composition by adding a ionomer (lonomer) is connected to the main chain molecule by substitution to form a ionic cluster (metal cluster) in the matrix resin In addition, the physical bond between the main chain of the matrix resin is increased to improve the mechanical properties of the composition.

In addition, the present invention provides a method for improving the mechanical properties of the matrix resin itself, unlike the existing methods for improving the mechanical properties of the composition by improving the affinity and dispersibility between the inorganic flame retardant and the matrix resin, using the present invention When the content of the flame retardant is increased, the mechanical properties of the composition may be prevented from deteriorating, and the amount of the inorganic flame retardant may be increased to further improve the flame retardancy of the composition.

Hereinafter, the present invention will be described in detail.

Polyolefin resins used in the present invention include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-vinylacetate (EVA), ethylene-ethyl acrylate (EEA) , Ethylene-methyl acrylate (EMA), ethylene-acrylic acid (EAA) and the like were used alone or in combination.

The ionomer used 3 to 30 parts by weight of an ionomer in which metal ions such as lithium, sodium, and zinc were substituted in the ethylene polymer.

In the ionomer used, the metal ions connected to the main chain molecules form an ionic cluster in the state of being mixed with the thermoplastic matrix polymer, and the matrix main chain is physically connected by the ionic aggregate, such as crosslinking by chemical bonding. Indicates.

The formation of the ion aggregate prevents the deterioration of the mechanical properties generated in the matrix resin by the addition of the flame retardant and the flame retardant aid.

The inorganic flame retardant is surface-treated with a binder such as saturated or unsaturated fatty acids such as stearic acid and oleic acid, vinyl trimethoxy silane, vinyl tri epoxy silane, titanate, and the like in aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium calcium carbonate and the like 1 Species or 2 to 4 species were mixed and used.

The particle size of the inorganic flame retardant was 0.5 to 30 µm, and the specific surface area was 3 to 20 m 2 / g, 50 to 180 parts by weight based on the matrix resin.

At this time, when using 50 parts by weight or less, flame retardancy and smoke resistance is inferior, and when using more than 180 parts by weight mechanical properties and workability is greatly reduced.

As a flame retardant aid, phosphoric compounds such as tricresyl phosphate, diphenylcresyl phosphate, red, silica, carbon black, and the like were used alone or in combination of two to four. The low molecular weight coupling agent (coupling agent) not only improves mechanical properties through physical bonding between the inorganic flame retardant and the matrix resin, but also lowers the viscosity of the mixture to improve processability and dispersibility of the inorganic flame retardant.

The amount of the low molecular weight binder is 0.5 to 5 parts by weight, in which the effect is not large when used at 0.5 parts by weight or less, and when used at 5 parts by weight or more, the deterioration of flame retardant properties is large.

As antioxidant, 0.5 to 3 parts by weight of amino-ketone system alone or mixed with benzimidazole system was used.

Hereinafter, the present invention will be described with reference to Comparative Examples and Examples as follows.

Example 1 Comparative Example 1 Example 2 Comparative Example 2 Example 3 Comparative Example 3 Ethylene-Vinyl Acetate 60 65 - - - - Ethylene-ethyl acrylate - - 70 80 - - Ethylene-Methylacrylate - - - - 75 80 Linear Low Density Polyethylene 30 35 - - - - Medium density polyethylene - - 15 20 13 20 Ionomer 1 (sodium ion substitution) 10 - 15 - - - Ionomer 2 (Zinc Divorce Substitution) - - - - 12 - Unsaturated fatty acid surface treated magnesium hydroxide - - 80 80 70 70 Unsaturated fatty acid surface treated aluminum hydroxide 150 150 - - - - Calcium carbonate 50 50 30 30 40 40 Phosphorus compound 4 4 3 3 5 5 Carbon black 5 5 2 2 3 3 Low molecular weight binders One One One One One One Amino ketone antioxidants 2 2 2 2 2.5 2.5 Oxygen Index (LOI) * 1 36 36 34 34 33 33 Smokeability (Dmax) * 2 70 70 80 80 80 80 Tensile Strength (㎏ / ㎠) * 3 1.35 0.88 1.24 0.82 1.32 0.87 Elongation (%) * 3 502 312 424 301 563 375

* 1: ASTM D2863

* 2: ASTM E662 (non-heating method)

* 3: KSM 3001-85

According to Comparative Examples 1, 2, and 3, the oxygen index and flame retardancy of flame retardancy are not different from those of Examples, but the tensile strength and elongation showing mechanical properties show better mechanical properties in Examples with ionomer added. Able to know.

As described above, the present invention has the effect of preventing the deterioration of mechanical properties due to the addition of the flame retardant in the polyolefin-based non-toxic (halogen-free) flame retardant material, thereby improving the flame retardancy.

Claims (7)

Inorganic flame retardant with respect to 3 to 30 parts by weight of ionomers in which metal ions are connected through substitution of a main chain molecule of an ethylene polymer with 97 to 70 parts by weight of a resin mixed with one or two or four thermoplastic polyolefin matrix resins 50 to 180 parts by weight, the flame retardant aid is 1 to 40 parts by weight, 0.5 to 5 parts by weight of a low molecular binder (Coupling agent), 0.5 to 6 parts by weight of the antioxidant, characterized in that the thermoplastic flame retardant resin composition. The method of claim 1, A thermoplastic flame retardant resin composition comprising a mixture of high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate and ethylene acrylic acid. The method of claim 1, Ionomer is a thermoplastic flame-retardant resin composition characterized in that the metal ion is connected to the main chain molecule of the ethylene-based polymer by substitution, the substituted metal ion is lithium, sodium or zinc ionomer. The method of claim 1, Inorganic flame retardants are surface-treated with a binder such as saturated or unsaturated fatty acids such as stearic acid and oleic acid, vinyl trimethoxy silane, vinyl tri epoxy silane, titanate, etc. Or 2 to 4 types are used by mixing a thermoplastic flame-retardant resin composition. The method of claim 4, wherein The particle size of the inorganic flame retardant is 0.5 to 30 ㎛, the specific surface area is a thermoplastic flame retardant resin composition using a 3 to 20 m 2 / g. The method of claim 1, The flame retardant aid is a thermoplastic flame retardant resin composition comprising a mixture of phosphoric compounds such as tricresyl phosphate, diphenylcresyl phosphate, red, silica and carbon black, or one or two to four kinds. The method of claim 1, The antioxidant is a thermoplastic flame-retardant resin composition characterized in that the amino-ketone type alone or mixed with benzimidazole type.