JPH0569132B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial application field The present invention is a flame-retardant ethylene that is based on a specific range of ethylene-α-olefin copolymer, has flexibility, and has excellent heat resistance, mechanical properties, and electrical properties. The present invention relates to a polymer composition. (b) Prior art Because polyethylene has excellent physical and chemical properties, it is molded into films, sheets, pipes, containers, etc. using various molding methods such as extrusion molding, injection molding, and rotary molding, and is used for household, It is a general-purpose resin with the highest demand for use in many industrial applications. Since the above-mentioned polyethylene is easily flammable, various methods for making it flame retardant have been proposed. The most common method is to add a flame retardant containing halogen or phosphorus to the polyethylene to make it flame retardant. The degree of flame retardation increases with the amount of flame retardant added. However, an increase in the amount added not only causes a decrease in mechanical strength, workability, etc., but also has the disadvantage of significantly impairing flexibility, cold resistance, etc. In addition, these conventional flame retardant compositions
From the perspective of disaster prevention, there is a trend in recent years to demand, and in some cases even mandate, a higher degree of flame retardancy. As a mold flame retardant,
Inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide meet these needs and are rapidly increasing in demand (for example, their technologies include:
JP-A-51-132254, JP-A No. 56-136832, JP-A No. 60-
(Publication No. 13832, etc.) However, conventionally commercially available polyethylene has poor receptivity to inorganic flame retardants and low flame retardant effects. In addition, when the filling amount is increased, mechanical strength, flexibility, workability, etc. decrease, resulting in a disadvantage that it cannot be put to practical use. On the other hand, it is well known that soft resins such as ethylene-vinyl acetate copolymer, chlorinated polyethylene, and ethylene-propylene copolymer rubber are used to increase the filling rate of the inorganic flame retardant. It becomes inferior in terms of mechanical strength, heat resistance, oil resistance, etc. (c) Problems to be solved by the invention In view of the above points, the present invention provides a low-smoke ethylene polymer composition that has excellent heat resistance, mechanical strength, low-temperature properties, flexibility, etc. Because of its particularly excellent electrical properties, it can be crosslinked as necessary and used as electrical materials such as insulation and sheathing for electric wires and cables, as well as for packing, sealing materials, hoses, films, etc. It is used for molding applications such as extrusion molded products and injection molded products, and as a master batch. (d) Means for Solving Problems The present invention provides (a) a material having a density of 0.86 to 0.91 g/cm ³ , a boiling n-hexane insoluble content of 10% by weight or more, and a maximum peak temperature shown by differential scanning calorimetry. 50 to 90 parts by weight of an ethylene-α-olefin copolymer having a temperature of 100°C or higher; (b) a copolymer of 50 to 95% by weight of ethylene and 5 to 50% by weight of an unsaturated carboxylic acid or its induction resistance;
or ethylene 50-95% by weight and vinyl acetate 5%
10 to 50 parts by weight of a copolymer with ~50% by weight; (c) 0 to 40 parts by weight of an ethylene-α-olefin copolymer having a density of 0.91 to 0.97 g/cm ³ and a higher density than component (a); (d) A low-smoke ethylene polymer composition containing 40 to 200 parts by weight of an inorganic flame retardant to 100 parts by weight of a resin component consisting of parts by weight (however, the total amount of a+b+c is 100% by weight). This is what we provide. The ethylene-α-olefin copolymer which is component (a) of the present invention is composed of ethylene and α-olefin having 3 to 12 carbon atoms.
It is a copolymer of olefin. Specific α-olefins include propylene, butene-1, 4-
Methylpentene-1, hexene-1, octene-1
1, decene-1, dodecene-1, and the like. Particularly preferred among these are propylene and butene-1. The α-olefin content in the ethylene-α-olefin copolymer is preferably 5 to 40 mol%. Below, ethylene used in the present invention and α-
A method for producing an olefin copolymer will be explained. First, the catalyst system used is a combination of a solid catalyst component containing magnesium and titanium with an organoaluminum compound. Examples of the solid catalyst component include magnesium metal, magnesium hydroxide, magnesium carbonate, magnesium oxide,
Oxygen-containing compounds such as magnesium chloride, double salts, double oxides, carbonates, chlorides, or hydroxides containing magnesium atoms and metals selected from silicon, aluminum, and calcium, as well as these inorganic solid compounds Examples include those in which a titanium compound is supported by a known method on an inorganic solid compound containing magnesium, such as one treated or reacted with a sulfur-containing compound, an aromatic hydrocarbon, or a halogen-containing substance. Examples of the above oxygen-containing compounds include organic oxygen-containing compounds such as water, alcohol, phenol, ketone, aldehyde, carboxylic acid, ester, polysiloxane, and acid amide, and inorganic oxygen-containing compounds such as metal alkoxides and metal oxychlorides. I can give an example. Examples of the sulfur-containing compound include organic sulfur-containing compounds such as thiol and thioether, and inorganic sulfur compounds such as sulfur dioxide, sulfur trioxide, and sulfuric acid. As aromatic hydrocarbons,
benzene, toluene, xylene, anthracene,
Examples include various monocyclic and polycyclic aromatic hydrocarbon compounds such as phenanthrene. Examples of the halogen-containing substance include compounds such as chlorine, hydrogen chloride, metal chlorides, and organic halides. Examples of the titanium compound include titanium halides, alkoxy halides, alkoxides, and halogenated oxides. Preferred titanium compounds are tetravalent titanium compounds and trivalent titanium compounds, and specific examples of tetravalent titanium compounds include the general formula Ti(OR) _o X _4-o (where R is 1 carbon number) ~20 alkyl, aryl or aralkyl groups, X represents a halogen atom, n
is 0≦n≦4), titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxymonochlorotitanium, tetramethoxytitanium, monoethoxy trichlorotitanium, diethoxychlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium,
Monoisopropoxytrichlorotitanium, diisopropoxydichlorotitanium, triisopropoxymonochlorotitanium, tetraisopropoxytitanium,
Monobutoxytrichlorotitanium, dibutoxydichlorotitanium, monopentoxytrichlorotitanium,
Examples include monophenoxytrichlorotitanium, diphenoxydichlorotitanium, triphenoxymonochlorotitanium, and tetraphenoxytitanium. As trivalent titanium compounds, titanium tetrahalides such as titanium tetrachloride and titanium tetrabromide are combined with hydrogen, aluminum, titanium, or the periodic table ~
Examples include titanium trihalides obtained by reduction with organometallic compounds of group metals. Also general formula
Ti(OR _{) n}
A trivalent titanium compound obtained by reducing a tetravalent halogenated alkoxytitanium represented by Can be mentioned. Among these titanium compounds, tetravalent titanium compounds are particularly preferred. Examples of other catalyst systems include solid catalyst components such as
Using a reaction product of an organomagnesium compound such as a so-called Grignard compound and a titanium compound,
An example of a catalyst system is a combination of this and an organoaluminum compound. Examples of organomagnesium compounds include general formula RMgX,
Organomagnesium compounds such as R ₂ Mg and RMg (OR) (where R is an organic residue having 1 to 20 carbon atoms, and X is a halogen) and ether complexes thereof,
Further, these organomagnesium compounds may be modified by adding other organometallic compounds, such as various compounds such as organosodium, organolithium, organopotassium, organoboron, organocalcium, and organozinc. In addition, as an example of another catalyst system, a solid material obtained by contacting an inorganic oxide such as SiO ₂ or Al ₂ O ₃ with a solid catalyst component containing at least magnesium and titanium is used as a solid catalyst component. ,
A combination of this and an organoaluminum compound can be exemplified. Inorganic oxides include CaO, B ₂ O ₃ , SnO ₂ and the like in addition to SiO ₂ and Al ₂ O ₃ , and double oxides of these oxides can also be used without any problem. Any known method can be used to bring these various inorganic oxides into contact with the solid catalyst component containing magnesium and titanium. That is, a method of reacting in the presence or absence of an inert solvent at a temperature of 20 to 400°C, preferably 50 to 300°C for usually 5 minutes to 20 hours, a method of co-pulverization, or a combination of these methods as appropriate. The reaction may be carried out by In these catalyst systems, a titanium compound can be used as an adduct with an organic carboxylic acid ester, or the above-described magnesium-containing inorganic solid compound can be used after being brought into contact with an organic carboxylic acid ester. Moreover, there is no problem in using an organoaluminum compound as an adduct with an organic carboxylic acid ester. Furthermore, in all cases it is also possible to use catalyst systems prepared in the presence of organic carboxylic esters without any problems. Here, various aliphatic, alicyclic, and aromatic carboxylic esters are used as the organic carboxylic ester, and aromatic carboxylic esters having 7 to 12 carbon atoms are preferably used. Specific examples include alkyl esters of benzoic acid, anisic acid, toluic acid, such as methyl and ethyl. A specific example of an organoaluminum compound to be combined with the above-mentioned fixed catalyst component is the general formula
R ₃ Al, R ₂ AlX, RAlX ₂ , R ₂ AlOR, RAl(OR)
An organoaluminum compound of X and R ₃ Al ₂ X ₃ (where R is an alkyl group, aryl group or aralkyl group having 1 to 20 carbon atoms,
R may be the same or different) Compounds such as triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum ethoxide, ethylaluminum sesquichloride, and mixtures thereof are preferred. can be mentioned. The amount of the organoaluminum compound to be used is not particularly limited, but it can usually be used in an amount of 0.1 to 1000 times the amount of the titanium compound. Furthermore, by bringing the catalyst system into contact with an α-olefin and then using it in the polymerization reaction, the polymerization activity can be greatly improved and the system can be operated more stably than in the case of no treatment. Various α-olefins can be used as the α-olefin used at this time, but α-olefins having 3 to 12 carbon atoms are preferable, and α-olefins having 3 to 8 carbon atoms are more preferable.
-Olefins are preferred. Examples of these α-olefins include propylene, butene-olefin, etc.
Examples include 1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, decene-1, dodecene-1, and mixtures thereof. The temperature and time during the contact between the catalyst system and the α-olefin can be selected within a wide range, for example,
The contact treatment can be carried out at ~200°C, preferably 0~110°C, for 1 minute to 24 hours. The α-olefin to be contacted can be selected from the widest range, but usually, 1 to 50,000 g of α-olefin is used per 1 g of the solid catalyst component, preferably 5 to 30,000 g, and 1 to 500 g of α-olefin is used per 1 g of the solid catalyst component. - It is desirable to react olefins. At this time, the pressure at the time of contact can be arbitrarily selected, but usually
It is desirable that the contact be made under a pressure of -1 to 100 kg/cm ² ·G. During the α-olefin treatment, the entire amount of the organoaluminum compound used may be combined with the solid catalyst component and then brought into contact with the α-olefin, or a part of the organoaluminum compound used may be combined with the solid catalyst component. After combining with α-olefin, the remaining organoaluminum compound may be added separately during polymerization to carry out the polymerization reaction. Further, when the catalyst system and the α-olefin are brought into contact, there is no problem even if hydrogen gas coexists, and there is no problem even if other inert gases such as nitrogen, argon, helium, etc. coexist. The polymerization reaction is carried out in the same manner as an ordinary olefin polymerization reaction using a Ziegler type catalyst. That is, all reactions are carried out substantially in the absence of oxygen and hydrogen, in a gas phase, in the presence of an inert solvent, or using the monomer itself as a solvent. The polymerization conditions for olefin are the temperature of 20 to 300℃, preferably 40℃.
~200℃, pressure is normal pressure to 70Kg/ ^cm2・G,
Preferably it is 2Kg/cm ² ·G to 60Kg/cm ² ·G. Although the molecular weight can be controlled to some extent by changing polymerization conditions such as polymerization temperature and catalyst molar ratio, it is effectively carried out by adding hydrogen to the polymerization system. Of course, a two-stage or more multi-stage polymerization reaction with different polymerization conditions such as hydrogen concentration and polymerization temperature can be carried out without any problem. The ethylene-α-olefin copolymer which is component (a) of the present invention produced in this manner has (a) a density of 0.86 to 0.91 g/cm ³ and (b) a boiling n-hexane insoluble content of 10 (c) It is important that the maximum peak temperature (Tm) shown by differential scanning calorimetry (DSC) is 100°C or more. If the above density exceeds 0.91 g/ ^cm3 , there is a concern that the composition will lose its flexibility, and the density will decrease.
If it is less than 0.86 g/cm ³ , the melting point will be low and the heat resistance will be poor. Furthermore, if the boiling n-hexane insoluble content of the ethylene-α-olefin copolymer is less than 10% by weight, the amorphous portion and low molecular weight components will increase, resulting in poor oil resistance and strength. On the other hand, materials with a maximum peak temperature (Tm) measured by differential scanning calorimetry (DSC) of less than 100°C also have poor heat resistance. The melt index (hereinafter abbreviated as MI) of the ethylene-α-olefin copolymer is 0.05 to 50 g/10
min, preferably in the range of 0.1 to 20 g/10 min. The method for measuring the boiling n-hexane insoluble matter and DSC in the present invention is as follows. [Measurement method for boiling n-hexane insoluble matter] A sheet with a thickness of 200 μm is formed using a heat press, and three sheets of 20 mm x 30 mm in length and width are cut from it, and the sheets are passed through a double-tube Soxhlet extractor. Extraction is carried out using boiling n-hexane for 5 hours. After taking out the n-hexane insoluble matter and vacuum drying (7 hours under vacuum, 50° C.), the boiling n-hexane insoluble matter is calculated using the following formula. Boiling n-hexane insoluble content (weight %) = (extracted sheet weight / unextracted sheet weight) × 100 (weight %) [Measurement method by DSC] Weigh approximately 5 mg of sample from a 100 μm thick hot press-molded film. Then, it was set in a DSC device, heated to 170°C, held at that temperature for 15 minutes, and then cooled to 0°C at a heating rate of 2.5°C/min. Next, from this state, the temperature is raised to 170°C at a heating rate of 10°C/min, and measurement is performed. The temperature at the position of the maximum peak that appears during the temperature increase from 0°C to 170°C is defined as Tm. The ethylene-α-olefin copolymer used in the present invention is clearly distinguished from the ethylene-α-olefin copolymer obtained by using vanadium as a solid catalyst component. That is, conventional ethylene propylene copolymers and the like have almost no crystallinity, and even if a crystal part exists, it is extremely small, and the maximum peak temperature (Tm) according to DSC is less than 100°C. This indicates that it cannot be used in applications that require heat resistance, mechanical strength, etc. The copolymer of ethylene and an unsaturated carboxylic acid or its derivative, which is component (b) of the present invention, refers to a copolymer of ethylene and an unsaturated carboxylic acid or an ester thereof, such as an ethylene-acrylic acid copolymer. , ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-maleic anhydride copolymer, etc., and metal salts thereof (e.g., ionomer resin, etc.). . The content of the unsaturated carboxylic acid or its derivative is in the range of 5 to 50% by weight, preferably 10 to 40% by weight. Another component (b) of the present invention is a copolymer of ethylene and vinyl acetate. The content of vinyl acetate is 5
~50% by weight, preferably 10-40% by weight. Among these, ethylene-ethyl acrylate copolymer, ionomer resin or ethylene-vinyl acetate copolymer are particularly preferred. The ethylene-ethyl acrylate copolymer (hereinafter simply referred to as EEA) has an ethyl acrylate content of 5 to 50% by weight, preferably 10 to 30% by weight. The ethylene-α-olefin copolymer which is the component (c) of the present invention includes low, medium and high density ethylene-α
- Includes olefin copolymers, with a density in the range of 0.91 to 0.97 g/cm ³ and always higher than the density of component (a), especially Polyethylene with a density in the range of 0.91 to 0.94 g/cm ³ , that is, what is usually called linear low-density polyethylene, has good compatibility with components (a) and (b) and is easy to mold and process. It is preferable in that it can easily maintain properties such as properties and flexibility. The melt index of the ethylene-α-olefin copolymer as component (c) is selected from the range of 0.05 to 50 g/10 minutes, preferably 0.1 to 20 g/10 minutes. Inorganic flame retardants of the present invention include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, basic magnesium carbonate, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, tin oxide hydrate, borax, etc. Hydrates of inorganic metal compounds, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate
Examples include calcium, calcium carbonate, barium carbonate, magnesium oxide, molybdenum oxide, zirconium oxide, tin oxide, antimony oxide, and red phosphorus. These may be used alone or in combination of two or more. Among these, magnesium hydroxide,
Aluminum hydroxide, basic magnesium carbonate,
At least one selected from the group consisting of hydrotalcite has a good flame retardant effect and is economically advantageous. The particle size of these flame retardants varies depending on the type, but for magnesium hydroxide, aluminum hydroxide, etc., the average particle size is preferably 20 μm or less. The above amount of inorganic flame retardant is based on 100 parts by weight of resin.
It ranges from 40 to 200 parts by weight, preferably from 70 to 150 parts by weight. If the amount of the heat retardant is less than 40% by weight, the flame retardant effect will be small, and if it exceeds 200 parts by weight, mechanical strength and elongation will decrease, flexibility will be lost, the product will become brittle, and low-temperature properties will also deteriorate. do. In the present invention, at least one of the above-mentioned additive flame retardants is used, and especially when a halogen flame retardant is used, it is preferably used in combination with antimony trioxide. Further, in the present invention, by using an inorganic filler and a flame retardant in combination, the amount of flame retardant added can be reduced and other properties can be imparted. Examples of the inorganic filler as an optional component used in the present invention include powder-like, tabular, scaly, needle-like, spherical or hollow, and fibrous, and specifically, calcium carbonate, magnesium carbonate, Calcium sulfate, calcium silicate, clay, diatomaceous earth, talc, alumina, silica sand, glass powder, iron oxide, metal powder, antimony trioxide, graphite,
Powder-like fillers such as silicon carbide, silicon nitride, silica, boron nitride, aluminum nitride, and carbon black, mica, glass plates, metal foils such as sericite, pyrofluorite, and aluminum flakes, and flat or scaly particles such as black smoke. hollow fillers such as glass balloons, metal balloons, glass balloons, pumice, mineral fibers such as glass fibers, carbon fibers, graphite fibers, whiskers, metal fibers, silicon carbide fibers, asbestos and wollastonite, etc. Examples can be given. The amount of these additives to be added is approximately 100 parts by weight per 100 parts by weight of the composition of the present invention. If the amount added exceeds 100 parts by weight, the mechanical strength such as impact strength of the molded article will decrease, which is not preferable. The composition of the present invention has (a) a density of 0.86 to 0.91 g/
cm ³ , boiling n-hexane insoluble content of 10% by weight or more, and maximum peak temperature (Tm) shown by differential scanning calorimetry (DSC) of 100°C or more, ethylene-α-olefin copolymer 50 in a specific range ~90 parts by weight; (b) a copolymer of 50 to 95% by weight of ethylene and 5 to 50% by weight of an unsaturated carboxylic acid or a derivative thereof;
Or 50-95% ethylene and 5-95% vinyl acetate
10 to 50 parts by weight of a copolymer with 50% by weight, and (c) an ethylene-α-olefin copolymer having a density of 0.91 to 0.97 g/cm ³ and a higher density than component (a).
A low-smoke, pollution-free type containing 40 to 200 parts by weight of (d) an inorganic flame retardant to 100 parts by weight of a resin component consisting of 40 parts by weight (however, the total amount of a+b+c is 100% by weight). This flame-retardant composition is based on a specific range of ethylene-α-olefin copolymer, so it can maintain heat resistance without losing flexibility. By using an oxygen-containing resin such as an ethyl copolymer, it is possible to increase the amount of flame retardant that can be accepted and to enhance the additive flame retardant effect. It is important that the amount of component (a) is in the range of 50 to 90 parts by weight. If the amount is less than 50 parts by weight, the heat resistance will decrease, and if it exceeds 90 parts by weight, the flame retardant effect will be poor, which is not desirable. Furthermore, by blending component c, if desired, it is possible to further improve heat resistance and mechanical strength. However, the amount of
If it exceeds 40 parts by weight, there is a concern that flexibility will be lost. In addition, in the present invention, when the inorganic flame retardant or inorganic filler is used, the surface of the inorganic material is coated with aliphatic acid such as stearic acid, oleic acid, palmitylic acid, or a metal salt thereof, paraffin, wax, etc. It is preferable to perform a surface treatment such as coating with polyethylene wax or a modified product thereof, organic silane, organic borane, organic titanate, or the like. The composition of the present invention comprises a specific range of ethylene-α-
The olefin copolymer, flame retardant, inorganic filler, additives, etc., if desired, are melt-kneaded using a commonly used kneader such as a Banbury mixer, pressure kneader, kneading extruder, twin screw extruder, roll, etc., and pelletized. In addition to being provided as a molded product or a masterbatch, it may also be a dry blend of the resin component, flame retardant, additives, etc. In the present invention, other synthetic resins, antioxidants, lubricants, various organic and inorganic pigments, ultraviolet inhibitors, dispersants, copper damage inhibitors, neutralizing agents, blowing agents, plasticizers, antifoaming agents, crosslinking agents, etc. Additives such as flow improvers, weld strength improvers, nucleating agents, etc. may be added to the extent that they do not significantly impair the effects of the present invention. (E) Example Next, an example will be described. Examples 1 to 9 and Comparative Examples 1 to 6 <Resin used> (a) Ingredients A solid catalyst component obtained from substantially anhydrous magnesium chloride, 1,2-dichloroethane and titanium tetrachloride, and a catalyst consisting of triethylaluminum. The polymerization of ethylene, propylene, and butene-1 was carried out using the following methods to obtain various ethylene-α-olefin copolymers as component (a) as shown below. (A) Ethylene-butene-1 copolymer (MI = 1.0 g/10 min, density = 0.905 g/cm ³ ) (B) Ethylene-butene-1 copolymer (MI = 0.8 g/10 min, density = 0.900g/cm ³ ) (C) Ethylene-propylene copolymer (MI = 0.5g/10 min, density = 0.890g/cm ³ ) (b) Component (D) Ethylene-ethyl acrylate copolymer (EA content 15% by weight, MI=0.8g/10min) (E) Ethylene-ethyl acrylate copolymer (EA content 10% by weight, MI=0.5g/10min) (F) Ethylene-vinyl acetate copolymer (VA Content 15% by weight, MI = 0.1 g/10 min) (c) Component (G) Ethylene-butene-1 copolymer (MI = 0.8 g/10 min, density = 0.935 g/cm ³ ) (Product name: Japan (H) Ethylene-butene-1 copolymer (MI = 1.0 g/10 min, density = 0.922 g/cm ³ ) (Product name: Nisseki Linirex AF2320, Nippon Petrochemical Co., Ltd.) Manufactured by Nippon Petrochemical Co., Ltd.) Add magnesium hydroxide (product name: Kisuma 5B, Kyowa Chemical Co., Ltd.) as a flame retardant to 100 parts by weight of the resin component consisting of specified amounts of components (a), (b) and (c) above. Co., Ltd.) was added in a predetermined amount and the physical properties were evaluated, and the results are shown in Table 1. Comparative Examples 7 to 10 As comparative examples, the following commercially available resins outside the scope of the present invention were used in place of component (a) of the present invention, and the results are shown in Table 1. (I) Ethylene-butene-1 copolymer (MI = 4.0 g/10 min, density = 0.887 g/cm ³ ) (Product name: Tafmer A4085, manufactured by Mitsui Chemicals, Inc.) (J) Ethylene-propylene copolymer Polymer (MI = 1.9 g/10 min, density = 0.86 g/cm ³ ) (Product name: EP02, manufactured by Japan Synthetic Rubber Co., Ltd.) <Test method> 1 Tensile strength 3 from a sheet with a thickness of 1 m/m Measurements were made using a test piece punched out of a No. 1 dumbbell using a tensilon at a tensile speed of 200 mm/min. 2 Heat resistance (heat deformation rate) A cylinder with a thickness of 6 m/m and a diameter of 10 m/m is heated to 100°C.
The specimen was pressurized with a load of 2.64 kg in an oil bath, and the deformation rate was determined after 30 minutes. 3 Flame retardancy Based on UL-Standard V-2. (i.e. average autolysis time less than 25 seconds and maximum digestion time
Less than 30 seconds. ) 4 Processability When extruded using a blow molding machine (screw diameter 25 m/m) using a die with an inner diameter of 9 m/m and an outer diameter of 10 m/m at a set temperature of 150°C and a screw rotation speed of 50 rpm. The surface condition was visually judged. 5 Oxygen index (OI)...D.2863-ASTM OI = Oxygen flow rate / Oxygen flow rate + Nitrogen flow rate x 100 Required for the sample to burn for more than 3 minutes or for the combustion flow to continue burning for more than 50 m/m minimum oxygen concentration.

【table】

[Table] (f) Effects of the invention As mentioned above, the flame retardant composition of the present invention contains a specific ethylene-α-olefin copolymer and EEA.
etc., it is possible to improve heat resistance and the filling rate of flame retardants without losing flexibility, and hydrates of inorganic metal compounds such as aluminum hydroxide, magnesium hydroxide, By using such materials, a flame-retardant composition that does not generate harmful gases during combustion, is low smoke, and is non-polluting, meets the recent needs for highly flame-retardant properties. Become. In addition, the low smoke ethylene polymer composition of the present invention may optionally contain linear low density polyethylene, etc.
Because it can further increase heat resistance and has excellent electrical properties, it can be used as electrical materials such as electrical insulation materials and outer covering materials for electric wires and cables, with or without crosslinking. I can do it. In particular, a high degree of flame retardancy is required for cables used in various power generation plants, including nuclear power research institutes that specify the amount of corrosive gases, cables for chemical, steel, and petroleum plants, fire-resistant electric wires, and general household wiring. It is suitable for use in places where It is also used for molding applications such as extrusion molded products such as films, sheets, and pipes, or injection molded products, and as a master batch, and is used as a panel in various fields such as textiles, electricity, electronics, automobiles, ships, aircraft, architecture, and civil engineering. , packaging materials, furniture, household goods, etc.

Claims (1)

[Scope of Claims] 1 (a) Density is 0.86 to 0.91 g/cm ³ , boiling n-hexane insoluble content is 10% by weight or more, and maximum peak temperature (Tm) shown by differential scanning calorimetry (DSC) 50 to 90 parts by weight of an ethylene-α-olefin copolymer having a temperature of 100°C or higher; (b) a copolymer of 50 to 95% by weight of ethylene and 5 to 50% by weight of an unsaturated carboxylic acid or a derivative thereof;
or ethylene 50-95% by weight and vinyl acetate 5%
10 to 50 parts by weight of a copolymer with ~50% by weight; (c) 0 to 40 parts by weight of an ethylene-α-olefin copolymer having a density of 0.91 to 0.97 g/cm ³ and a higher density than component (a); Parts by weight (however, the total of a+b+c is
100 parts by weight of a resin component (100 parts by weight), and (d) 40 to 200 parts by weight of an inorganic flame retardant. 2. The low smoke ethylene polymer composition according to claim 1, wherein the component (b) is an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer. 3. The low smoke ethylene polymer composition according to claim 1 or 2, wherein the component (c) is linear low density polyethylene having a density of 0.91 to 0.94 g/cm ³ . 4. The low smoke ethylene polymer composition according to claim 1, 2 or 3, wherein the inorganic flame retardant is a hydrate of an inorganic metal compound. 5. The low smoke ethylene polymer composition according to claim 4, wherein the hydrate of the inorganic metal compound is aluminum hydroxide or magnesium hydroxide.