JPS5918742A - Flame-retardant composition - Google Patents

Abstract

PURPOSE:To prepare a composition having high flame-retardance, good low- temperature resistance and excellent weatherability, and suitable for injection molding, by compounding a low-density PE, a high-density PE and a chlorinated PE with an inorganic material having Si-O bond in combination with conventional flame retardant. CONSTITUTION:The objective composition can be obtained by compounding (A) a low-density PE having a density of 0.905-0.930g/cm<3>, a melting point of 106- 130 deg.C, an M.I. of 0.01-100g/10min, and having 3-35, 1-10C side chain alkyl groups per 1,000C atoms of the main chain, with (B) a high-density PE having a density of 0.930-0.980g/cm<3>, a melting point of 112-140 deg.C, an M.I. of 0.01- 100g/10min, and having <=8 1-10C side chains per 1,000C atoms of the main chain, (C) a chlorinated PE having a chlorine content of 20-50wt%, (D) an halogen-containing compound and/or antimony oxide, and (E) an inorganic material having Si-O bond (preferably having an SiO2-content of >=50wt%). The ratio of each component is defined as follows: 5-50pts.wt. of the component (D) and 5-15pts.wt. of the component (E) are added to 100pts.wt. of a resin composed of 35-85wt% of the component (A), >=5wt% of the component (B) and 10-50wt% of the component (C).

Description

[Detailed Description of the Invention] [■] Object of the Invention The present invention relates to (A) low density polyethylene, (B) high density polyethylene, (C) chlorinated polyethylene, (D) C'
f > Concerning a flame-retardant composition consisting of a containing compound and/or (fragrant antimony and (F) an inorganic substance having a Si-0 bond), the composition has excellent weather resistance and is suitable for injection molding. The purpose is to provide

[Background of the Invention] In recent years, the demand for flame-retardant compositions has continued to increase, and performance requirements for flame-retardant compositions have become more severe. For example, when wiring high-voltage power distribution lines to construction sites such as civil engineering and construction, it is difficult to use conventional covers to protect structures, trees, and other nearby areas. The flammability was sufficient at V-2 according to the UL-94 standard. However, recently, highly flame-retardant compositions have been desired due to the frequent occurrence of combustion, melting and dripping, and ignition accidents at the above-mentioned close locations. Therefore, in conventional flame retardant compositions, a large amount of flame retardant is added because (1) the flame retardance is insufficient. Therefore, not only sufficient mechanical strength and processability cannot be obtained, but also expensive flame retardants are used in large quantities, making them expensive.

I. Structure of the Invention Based on the above, the present inventors have discovered that the flame retardant property is excellent (UL
As a result of various searches to obtain a composition that not only has good weather resistance but also is suitable for injection molding, we found that the composition has a density of less than 0900 to 0.9309/cm and a melting point of The temperature is 106 to 130℃, and the melt index (temperature is 19 according to JIS K-6760).
Measured under the conditions of 0°C and a load of 2.16 kg, below 1
"M, 1.j) is 0.01 to 100 g/10 min, and the number of side chain alkyl groups having substantially 1 to 10 carbon atoms is 3 to 35 per 1000 main chain carbon atoms. Low density polyethylene, (131 density 0.930~0.9' 80 & 7c
m'', has a melting point of 112 to 140°C, and M,
I.

is 0.01 to 100.9/10 min, and the number of carbon atoms per 1000 carbon atoms in the main chain is at most 8 and at most 10
(C) Amorphous or crystalline chlorine content of 20~
500 to 50 weight part hydrogenated polyethylene, (I)) a halogen-containing compound and/or (E) antimony oxide, and (F) an inorganic substance having a Si-0 bond, the low density polyethylene, high density polyethylene and chlorinated The content of chlorinated polyethylene in the total amount of polyethylene is 10 to 500 to 50 parts by weight, the content of low density polyethylene is 35 to 85 parts by weight, but the content of high density polyethylene is at least 5 parts by weight, A flame retardant composition in which the sum total of the halogen-containing substance and antimony oxide is 5 to 50 parts by weight, and the blending ratio of the inorganic substance is 5 to 15 parts by weight, based on 100 parts by weight of these, has flame retardant and It was discovered that the composition not only has good cold resistance but also excellent weather resistance and is suitable for injection molding, and the present invention was achieved.

[IV] Effects of the Invention The composition obtained by the present invention further has the following characteristics (effects).

(1) '81. Mechanically strong deformation (e.g., tensile strength, tensile elongation), especially tensile strength.

(2) Excellent workability.

(3) Heat resistance is also good.

(4) Regarding flame retardancy, it is equivalent to V-O according to UL standards, and is highly flame retardant.

(5) It is cold resistant and has excellent resistance to stress cracks.

(6) Since moldability is good, molded products with complicated shapes can be manufactured.

(7) It has excellent weather resistance, so even if exposed outdoors for a long period of time, there will be almost no cranking.

The composition obtained by the present invention has the above-mentioned effects and can be used in a wide variety of fields. Typical uses are shown below.

(1) Clamp cover for high-voltage or low-voltage electric wires (2) Detention cover for building obstructions (structures, trees, etc.) (3) Detention cover for communications (4) Cable sheath material (5) Fire-resistant electric wire sheath material for firefighting ■ Invention Detailed Description (A) Low-density polyethylene The low-density polyethylene used in the present invention is obtained by copolymerizing ethylene and α-olefin. The density of the low density polyethylene is 0.900-0.9
Less than 40 jj/cm3, 0905-094
Less than 0g/Crn3 is better <, WKO905~o, q
3o, 9/Kushi 3 is suitable.

The density of this low density polyethylene is o9oo, 9/Crn
If it is less than 3, the resulting composition will not have sufficient rigidity. On the other hand, if it exceeds 0.940 fl/cm3, the rigidity is high, but the flexibility is insufficient, so it is not suitable.

In addition, the melting point is 106 to 130°C, and 106 to 125
The temperature is preferably 110 to 125°C. If low density polyethylene with a melting point of less than 106° C. is used, the resulting composition will not have sufficient rigidity or heat resistance. On the other hand, if low-density polyethylene with a melting point exceeding 130° C. is used, the resulting composition will have high rigidity, but will lack flexibility, which is unsuitable.

Furthermore, M and I of low density polyethylene are 0.01 to 1
00.9/10 minutes, preferably 01 to 50 g/10 minutes, particularly preferably 5 to 30.9/10 minutes. When M and I of the low density polyethylene are less than 0.01 p/10 min, moldability is poor. On the other hand, if the time exceeds 100.9/10 minutes, moldability is good, but a good product cannot be obtained due to lack of appropriate rigidity.

The α-olefin used in the production of the low-density polyethylene is an α-olefin having at most 12 carbon atoms, and typical examples include propylene, butene-1, and hexene-1.
, 4-methylpentene-1 and octene-1. The copolymerization ratio of the α-olefin in this low density polyethylene is usually 10 to 18% by weight.

What is short chain branching in this ethylene-based linear copolymer?
Refers to a chain having branches that are sufficiently short compared to the main chain, for example, having less than 10 carbon atoms. On the other hand, a long chain branch means a branch having a length sufficiently comparable to that of the main chain, and having, for example, 10 or more carbon atoms.

(B) High-density polyethylene The high-density polyethylene used in the present invention is obtained by homopolymerizing ethylene or copolymerizing ethylene and α-olefin. The density of the high density polyethylene is 0930-0.980177 cm3, preferably 0.930-0.975 g/cT7I3, particularly preferably 0.930-0.972 g/CTn3. The density of this high density polyethylene is 0.930
, j9/o++'', the resulting composition has low mechanical strength (especially tensile strength).

In addition, the melting point of this high density polyethylene is 112 to 140
℃, preferably 115-140℃, especially 11
A temperature of 8 to 140°C is suitable. If the melting point of the high-density polyethylene is less than 112°C, the resulting composition will have low mechanical strength (especially tensile strength). On the other hand, the melting point force'-140
If high-density polyethylene with a temperature higher than 0.9°C is used, the workability of the resulting composition will be poor, and cracks will easily occur at the hinge. Furthermore, M of the high density polyethylene, 1. is 0.01~100g/1
0 minutes, preferably 01 to s o g / 10 minutes, particularly preferably 1 to s o / 1 o minutes. The M of this high density polyethylene is 1. is 0. If the time is less than 9/10 minutes, the moldability of the resulting composition will be poor. On the other hand, 100
If it exceeds g/10 minutes, the moldability of the composition is good, but a good product cannot be obtained because it lacks appropriate rigidity.

This high-density polyethylene essentially has 10 carbon atoms in its main chain.
The number of carbon atoms per 00 carbon atoms is at most 8 and has at most 10 side chains (short chain branches). In the high-density polyethylene of the present invention, "11" essentially consists of the above-mentioned short chain branches, and also includes a very small number of carbon atoms having side chains of 11 or more.

The α-olefin used to produce the high-density polyethylene generally has at most 12 carbon atoms (preferably 8 carbon atoms).
Typical examples include propylene, butene-1, hexene-1,4-methylpentene-1, and octene-1. The copolymerization ratio of α-olefin in this copolymer is usually at most 5 parts by weight.

(C1 Chlorinated polyethylene The chlorinated polyethylene used in the present invention is obtained by chlorinating polyethylene powder or particles in an aqueous suspension, or by chlorinating polyethylene dissolved in an organic solvent. (Preferably, those obtained by chlorination in an aqueous suspension) are generally amorphous or crystalline chlorinated polyethylenes with a chlorine content of 20 to 50% by weight; is 25-4
545% by weight crystalline and crystalline chlorinated polyethylene are preferred. The polyethylene of this chlorinated polyethylene is a homopolymer of ethylene or at least 10 polymers of ethylene.
% of α-olefin (generally having at most 6 carbon atoms). Its density is generally 0.910-0.9701/cm
There is f. Moreover, its molecular weight is 50,000 to 700,000.

The polyethylene used as a raw material for the production of the low-density polyethylene, high-density polyethylene, and the chlorinated polyethylene is ethylene-based, or ethylene and the above-mentioned α-olefin are combined into so-called Ziegler.
r) Obtained by homopolymerization or copolymerization in the presence of a catalyst or a Phillips catalyst. Ziegler catalysts are transition metal compounds (e.g. titanium) 10
A so-called carrier-supported solid catalyst obtained by supporting a magnesium-containing compound) or the transition metal compound on a carrier (e.g., a magnesium-containing compound, a compound obtained by treating the magnesium-containing compound with an electron-donating organic compound). It is obtained from the components and an organoaluminum compound. Phillips catalyst is a carrier-supported catalyst obtained by supporting a chromium or molybdenum oxide or a compound of these oxides and zirconium on a carrier (for example, silica, silica-alumina), or a carrier-supported catalyst obtained by supporting the carrier-supported catalyst and an organic metal. It is obtained from a compound. The above catalysts are merely typical Ziegler catalysts and F1) Laps catalysts, and other known catalysts may also be used. The method for producing this copolymer is also a well-known method.

(D+ Halogen-containing compound The /SS rosin-containing organic compound used in the present invention is widely known as a flame retardant.

Representative examples include tetrachlorophthalic anhydride, chlorinated paraffin, chlorinated bisphenol A1, brominated bisphenol Sj,! phenyl, brominated diphenyl, chlorinated naphthalene, tris (β-chloroethyl) phosphate, and tris (dibromobutyl) phosphate.

(g)) Antimony oxide Further, the antimony oxide used in the present invention is generally used as a flame retardant aid for the halogen-containing organic compound. Representative examples include triliquefied antimony and antimony pentoxide.

These halogen-containing organic compounds and antimony oxide are well known from the above-mentioned "Handbook, Rubber/Plastic Compounded Chemicals" and the like.

(F) Inorganic substance having a Si-0 bond The content of 5i02 in the inorganic substance having a 5i-0 bond used in the present invention is usually at least 10% by weight, preferably 30% by weight or more, particularly 50% by weight or more. is suitable. The content of H2O is usually 1.0 to 20% by weight, preferably 10 to 15% by weight, especially 15% by weight.
-15 weight ratio is suitable. Further, the particle size of the inorganic substance is generally 10 mm to 30 mm, particularly preferably 10 mm to 25 mm, particularly preferably an inorganic substance having a particle size of 15 mm to 25 mm. be.

Typical examples of inorganic substances having a 5i-0 bond include wet process white carbon and calcium chloride.

Colloidal silica, synthetic silicate white carbon containing some oxides of calcium, aluminum, sodium, iron, etc., ultrafine magnesium silicate, aluminum silicate (clay).

Examples include talc, nepheline feldspar, mica powder, silica powder, diatomaceous earth, and silica sand. Regarding the inorganic substances that bind these 5i-0 bonds, please refer to Rubber Digest Publishing Co., Ltd.'s "Handbook of Rubber and Plastic Compound Chemicals" (Rubber Digest Co., Ltd., published in 1971), pages 221 to 253.
Each page describes their manufacturing method, physical properties, product name, etc., and is well known.

(G) Blending ratio (mixing ratio) In producing the flammability composition of the present invention, the content ratio (blending ratio) of chlorinated polyethylene in the total of low density polyethylene, high density polyethylene and chlorinated polyethylene is 10 to 10. 500-50 parts by weight are preferred, 10-45 parts by weight are particularly preferred, and 15-45 parts by weight are particularly preferred. The proportion of chlorinated polyethylene in the total of these is 10
If the M coefficient is less than 90 parts by weight (the total blending ratio of low density polyethylene and high density polyethylene exceeds 90 parts by weight), a composition with good flame retardancy cannot be obtained. On the other hand, if it exceeds 500 parts by weight, a composition with good flame retardancy can be obtained, but a composition with good processability and moldability cannot be obtained, so that an excellent molded article cannot be obtained. In addition, the content of low density polyethylene in the total of these is 35 to 85 parts by weight, and 35 to 805 parts by weight.
-80 parts by weight, especially 35-705-70 parts by weight.

The content of low-density polyethylene in the total of these (
If the blending ratio) is less than 35 parts by weight, moldability will be poor;
If it exceeds 85 parts by weight, mechanical strength (particularly tensile strength) will be poor. Furthermore, the blending ratio of high density polyethylene is at least 5 parts by weight, preferably 7 parts by weight or more,
A weight ratio of 7 to 30 is suitable. If the proportion of high-density polyethylene in the total of these is less than 5 parts by weight, the machine
Deformation strength (especially tensile strength) is low.

Furthermore, the blending ratio of the halogen-containing organic compound and antimony oxide to the total amount of low-density polyethylene, high-density polyethylene, and chlorinated polyethylene] and O0 parts by weight is 5 to 50 parts by weight, and 10 parts by weight.
-50 parts by weight is desirable, and 10-45 parts by weight is particularly preferred. The blending ratio of antimony oxide to the halogen element 12fa in 3.00 parts by weight of the halogen-containing organic fraction is generally 100 to 600 parts by weight, and 10 parts by weight.
It is preferably 0 to 400 parts by weight, and particularly preferably 150 to 400 parts by weight from the viewpoint of flame retardancy and bleedability.

The important point of the present invention is that in addition to the usual flame retardant formulation consisting of a usual flame retardant (2000), a rogen-containing organic compound, and antimony oxide), it also has good moldability and high flame retardancy (UL-9
Low density polyethylene to give v-〇) by method 4,
Total amount of high density polyethylene and chlorinated polyethylene 1
00 parts by weight of inorganic substances with 5i-0 bonds
~15 heavy tails, especially 7~15
It is preferable to mix parts by weight.

In producing the composition of the present invention, low-density polyethylene, high-density polyethylene, chlorinated polyethylene, halogen-containing organic compounds, antimony oxide, and inorganic substances having Si-0 bonds may be used alone or in combination. Tool 2 may be used in combination.

(H) Production of compositions and production of molded products Although the composition of the present invention can be obtained by uniformly blending the above-mentioned materials, it is also generally used in the chlorinated polyethylene rubber industry and the polyethylene industry. Fillers, mold release agents, oxygen, ozone and light (
Additives such as stabilizers against UV rays, binders, lubricants, and colorants may be added depending on the intended use of the composition.

In addition, sulfur vulcanizing agents, sulfur-releasing compound-based vulcanizing agents, amine-based vulcanizing agents, organic peroxide-based crosslinking agents, and organic peroxide-based crosslinking coagents commonly used in the rubber industry and resin industry, etc. Additives may be added depending on the intended use of the composition.

When producing the composition of the present invention, the blending (mixing) method is as follows: Mixing may be carried out using a mixer such as an open roll, a dry blender, a Banbury mixer, and a Nigu mixer commonly used in the art. good. Among these mixing methods, in order to obtain a more uniform composition, two or more of these mixing methods may be applied (for example, after mixing in advance with a dry blender, the mixture may be mixed using an open roll. How to mix).

Additionally, all of the ingredients may be mixed at the same time, or some of the ingredients may be mixed in advance, and then the remaining ingredients may be mixed into the resulting mixture (for example, low-density polyethylene, high-density polyethylene, A method in which polyethylene, chlorinated polyethylene, a halogen-containing organic compound, and antimony oxide are mixed in advance, and then the resulting mixture is mixed with an inorganic substance having a 5t-0 bond.

The composition of the present invention may be molded into a desired shape using molding machines commonly used in the rubber industry, such as extrusion molding machines, injection molding machines, compression molding machines, and calender molding machines. In addition, a method of manufacturing a molded product by adding chlorinated polyethylene or the above-mentioned composition and vulcanizing (crosslinking) it in the rubber technology field, that is, a method of simultaneously proceeding vulcanization and molding, is applied. It may be formed into a desired shape.

Leaf Examples and comparative examples The present invention will be explained in more detail below with reference to Examples.

In addition, in the examples and comparative examples, the tensile test was conducted according to JIS
Measured according to C-3005.

In addition, the heat resistance test was carried out in accordance with JISC-3005 after being left in a gear oven at a temperature of 90° C. for 96 hours. Furthermore, the heating deformation test was 90±2
After leaving it in a constant temperature chamber set at ℃ for 1 hour, take it out,
A test was conducted to determine whether deformation occurs due to softening or the like. In addition, in the cold resistance test, a sheet (2.5 cm thick) manufactured as described below was left in a -20°C constant temperature premises for a period of time, then bent at 180 degrees, and whether or not cracks appeared. Tested. Furthermore, the heat resistance test is based on JIS K-6911.
Section 5.24, flame resistance was measured by method A. In addition, flame resistance is determined by Underwriters Laboratories (UL).
It was measured according to the 94 method.

The ingredients used in the Examples and Comparative Examples were manufactured by the following shapes, physical properties, and manufacturing methods.

[Low density polyethylene]

As low density polyethylene, density force'-o920. ! i
'/Qn3 linear copolymer of ethylene and butene-1 [MJ, 15,! 9/10 minutes, melting point 120
°C, number of side chain alkyl groups per 1000 main chain carbon atoms 7, side chain alkyl groups mainly ethyl groups, hereinafter r
PE(A)j] and the density force'-09169/c
Linear copolymer CM of ethylene and hexene-1 which is 1n3, 1.23g 710 minutes, melting point -116°C, number of side chain alkyl groups per 1000 main chain carbon atoms 12,
A butyl group (hereinafter referred to as "PE(B)") was used as the alkyl side chain.

[High-density polyethylene]

As high density polyethylene, the density is Q. 955g/c1
High-density polyethylene that is n3 (■Xri.1.209
/1 0 minutes, hereinafter referred to as r P E (a)] and the density is 0. g 6 1, g 7 cm3 [M. ■, B2jj/1.0 minutes, hereinafter referred to as “P
E(b)] was used.

[Chlorinated polyethylene]

Density is 0940g/crn as chlorinated polyethylene
3. Polyethylene (average molecular weight approximately 200,000) is chlorinated by an aqueous suspension method, and the chlorine content is 303% by weight hereditary polyethylene [density 106g/c1n3, Mooney viscosity (ML, +, (120℃)] 82,5,
poor quality, hereinafter referred to as "CPE (1)"] and density is 0
．． 9 3 i g/Cm3 polyethylene (average molecular weight approximately 150,000) was chlorinated by an aqueous suspension method to produce chlorinated polyethylene with a chlorine content of 30.1 g/cm3 [density 1
05 9 7cm3, A-=-viscosity (ML, 4 (120
℃) ) 1 0 7. 0, crystalline, hereinafter referred to as "CPE (2)"] was produced.

[Halogen-containing organic compound and antimony oxide] As the halogen-containing organic compound, chlorinated paraffin (molecular weight: about 1060, chlorine content: about 70, hereinafter referred to as "Salt Nokura") having a density of 166 g/m3 was used.

Also, as antimony oxide, the density is 5. 2 5 &
7 cm3 of antimony trioxide (hereinafter referred to as "5b203")
) was used.

[Inorganic substance having a 5i-0 bond] As an inorganic substance having a 5i-0 bond, ultrafine magnesium silicate (density 2.75 jj 7cm3, specific surface area 20m2/g, particle size 0.32 to 6 hecron, 5i
02 content 62.5% by weight, MgO content 306% by weight, Fe2O3 content 10% by weight, ■]
20 content 49999% by weight (called MgO-8i~), aluminum silicate (density 261g/cTn)
, particle size 2-5 microns, SiO content 506 heavy nails,
Aj'203 content 34848% by weight 20 content 44
．． 1. , 5% by weight, hereinafter referred to as "Al2O3・SiO2"), silica (density 1.g 597cm, specific surface area 19.000c1n2/g, average particle size 16 millimicrons, SiO content 86.5% by weight, H20 content) Amount 13.0% by weight, hereinafter referred to as 1'-8iO□) and calcium silicate (density 2.19/cm2,
Average particle size 40 mm, specific surface area ''/g, s
i02 content 72% by weight, CaO content 10% by weight, H2O content 1.5% by weight, hereinafter rca()Si
O, J) were used.

Examples 1 to 13, Comparative Examples 1 to 10 The above composition components (low density polyethylene, high density polyethylene, chlorinated polyethylene, halogen-containing organic compound,
antimony oxide, an inorganic substance having a 5i-0 bond) in the amounts shown in Table 1 (all parts by weight) and 5 parts by weight of tribasic lead sulfate as a stabilizer (however, in Comparative Example 1, no addition was made). A composition (mixture) was prepared by melting and kneading the mixture in advance at a temperature range of 120 to 140° C. using a Ni-Goo. Sheets were prepared from each of the obtained mixtures using a mixing roll set at 50°C.

Pellets were created from each of the obtained sheets using sheet cutting. Each of the pellets thus obtained was processed using an extruder (diameter: 50 mm, L/D: 26), with cylinder 1 at a temperature of 130°C and cylinder 2 at a temperature of 145°C.
°C, temperature of cylinder 3 150 °C, temperature of die 1
Pelletizing was performed under the conditions of 50° C. and a rotation speed of 30 revolutions/min to prepare pellets. These pellets were molded using an extruder using an injection molding machine (manufactured by Kokusha Co., Ltd., 5 ounces, cooling time 30 seconds), nozzle heater 1 temperature 200℃, heater 1 temperature 200℃, heater 2 temperature 170℃.
The sheet was prepared under the conditions of 160° C. and the temperature of the heater 3.

The sheets thus obtained were prepared for the following physical property tests, and tensile strength, heat resistance tests, heat deformation tests, and cold resistance tests were conducted. Furthermore, the flame resistance test was carried out using a press machine set at a temperature of 150°C using the above pellets produced in an extruder, under a pressure of 100 kg / an 2 (gauge pressure) for 5 minutes, and the thickness was determined. is 2.5
A job sheet was created and an exam was conducted.

The results obtained are shown in Table 2.

12C.

In Comparative Example 2, injection molding was attempted to create a sheet, but the sheet could not be manufactured.

From the results of the following seven Examples and Comparative Examples, it is clear that the flame retardant composition obtained by the present invention shows good values in the tensile test, heat resistance test, and cold resistance test, and also shows good values in the dragon flame resistance test. Since it is clear that the material has excellent properties, it is clear that it has a promising future as a material for high-voltage or low-voltage electric covers, cable sheath materials, etc. as mentioned above.

Patent applicant: Showa Denko Co., Ltd. Agent: Patent Attorney Sei Kikuchi 302-

Claims (1)

[Claims] (A) Density is 0.905 to 0.930 Et/cm
3, the melting point is 106 to 130°C, the melt index is 0.01 to 100, 9/1.0 min, and the number of side chain alkyl groups substantially has 1 to 10 carbon atoms. (B) low density polyethylene with a density of 3 to 35 per 1000 chain carbon atoms, (B) a density of 0.930 to 0.9 s;
Ofj 7cm3, melting point is 112-140°C, and melt index is 001-] 009
'/1o min, and has at most 8 carbon atoms and at most 10 side chains per 1000 carbon atoms in the main chain; (C) amorphous to crystalline chlorine content; 20～
50% by weight of chlorinated polyethylene, (D) a halogen-containing compound and/or (D) antimony oxide, and (D) an inorganic substance having a Fist-0 bond, the sum of the low density polyethylene, high density polyethylene and chlorinated polyethylene. The content of chlorinated polyethylene is 10 to 50% by weight, and the content of low density polyethylene is 35 to 85% by weight, but the content of high density polyethylene is at least 5% by weight, and these A flame retardant composition, wherein the total amount of the halogen-containing substance and antimony oxide is 5 to 50 parts by weight, and the proportion of the inorganic substance is 5 to 15 parts by weight, based on 100 parts by weight of the total amount.