JPH0912792A - Flame retardant ethylenic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ethylene-based resin composition having high flame retardance and good processability and other characteristics, remarkably excellent in mechanical characteristics, compared with conventional compositions and suitable for electric wire coating, etc. SOLUTION: This ethylenic resin composition is composed of 100 pts.wt. of a substantially linear ethylene-α-olefin copolymer (e.g. ethylene-octene-1 copolymer) having 0.5-50g/10min melt flow and <=3.0Mw/Mn and produced by using single site catalyst and 5-250 pts.wt. flame-retardant [e.g. Mg(OH)2 , Al(OH)3 or SbO3 ].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant ethylene-based resin composition, and more specifically, it is excellent in flame retardancy, low temperature characteristics, environmental stress cracking resistance, etc., and is more excellent in mechanical characteristics than conventional ones. The present invention also relates to a flame-retardant ethylene-based resin composition which has good insulating properties and workability and can be suitably used for coating electric wires.

[0002]

2. Description of the Related Art Conventionally, flame-retardant ethylene-based resin compositions have been used as a base material, such as branched low density polyethylene (HPLDPE), ethylene-vinyl acetate copolymer (EVA) and ethylene- Ethyl acrylate copolymers (EEA) are used, which are combined with organic flame retardants based on, for example, organic halogen flame retardants or organic phosphorus flame retardants, or
For example, it has been used by combining with an inorganic flame retardant mainly composed of magnesium hydroxide. Further, in order to improve the heat resistance and mechanical properties of these flame-retardant ethylene-based resin compositions, the present applicant has used a linear / ultra-low density ethylene-α-olefin copolymer (VLDP) as a base material.
A composition using E) was developed (JP-A 61-213).
238 and JP-A-63-72744). Although these flame-retardant ethylene-based resin compositions have achieved the object for the time being, mechanical properties have not yet been sufficiently satisfied due to the fact that a large amount of flame-retardant is blended with the ethylene-based resin.

[0003]

DISCLOSURE OF THE INVENTION The present invention has improved the above-mentioned drawbacks of the flame-retardant ethylene-based resin composition and is excellent in flame retardancy, low temperature characteristics, environmental stress cracking property, etc. An object of the present invention is to provide a flame-retardant ethylene-based resin composition having excellent characteristics, good insulating properties, and good workability, which can be suitably used for coating electric wires.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventor found the following composition and completed the present invention. That is, the present invention has a melt flow rate of 0.5 to 50 g / 10 minutes and a density of 0.86 to
Substantially linear produced using a single-site catalyst having 0.91 g / cm ³ and a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 3.0 or less. Ethylene-α-olefin copolymer 100
The present invention relates to a flame-retardant ethylene-based resin composition comprising 5 parts by weight and 5 to 250 parts by weight of a flame retardant.

Ethylene-α-used in the present invention
The olefin copolymer is the base material of the composition of the present invention, and is composed of ethylene and α-olefin, for example, having 3 carbon atoms.
Nos. 12 to 12 are copolymers with α-olefins. α-
Specific examples of the olefin include propylene and butene-
1, hexene-1, 4-methylpentene-1, octene-1, decene-1, dodecene-1 and the like. Among these, octene-1 is particularly preferable from the viewpoint of mechanical properties and processability of the flame-retardant ethylene resin composition.

The ethylene-α-olefin copolymer used in the present invention has the following physical properties: melt flow rate 0.5 to 50 g / 10 minutes, density 0.86 to 0.9.
Those having a ratio (Mw / Mn) 3.0 The following 1 g / cm ³ and a weight average molecular weight (Mw) to number average molecular weight (Mn). Here, the melt flow rate is JIS K
Measured in accordance with 7210. If it is less than 0.5 g / 10 minutes, the moldability is poor, and if it exceeds 50 g / 10 minutes, the mechanical properties are poor, which is not desirable. Also, the density is JIS
K7112 is measured according to, it is difficult to manufacture and is less than 0.86 g / cm ^3, exceeds 0.91 g / cm ^3, uniform dispersion of the flame retardant to the ethylene -α- olefin copolymer It is not desirable because it cannot be retained. Further, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is measured by size exclusion chromatography and needs to be 3.0 or less, preferably 2.5. It is the following. If Mw / Mn exceeds 3.0, mechanical properties are inferior, which is not desirable.
This Mw / Mn is a value that serves as an index of the molecular weight distribution, and the smaller the value, the smaller the molecular weight distribution.

In the present invention, the single-site catalyst used in the production of the above ethylene-α-olefin copolymer has the same active site (single site) and has a high polymerization activity for ethylene. Is. This single-site catalyst is also referred to as a metallocene catalyst or, as the inventor's name, a Kaminsky catalyst. The catalyst used in the present invention is a further improved one, for example, a catalyst having a constrained geometry (Constrain).
ed Geometry Catalysts), a metal atom of Group 3 to 10 of the periodic table or a lanthanoid (lanthanum series), and an atomic group having a delocalized π (pi) bond substituted with an atomic group that induces a constraint. Those containing a metal coordination complex containing is preferable. A preferred catalyst complex has the formula:

Embedded image (In the formula, M is a metal atom of Group 3 to 10 of the periodic table or a lanthanoid, and Cp * is a cyclopentadienyl group or a substituted cyclopentadienyl group bonded to M in a η ⁵ bond mode, Z is an atomic group containing boron or an element of Group 14 of the periodic table, and optionally a sulfur atom or an oxygen atom, the atomic group having up to 20 atoms other than hydrogen atom, or Cp * And Z together form a fused ring system, X independently of one another is an anionic ligand or a neutral Lewis base ligand having up to 30 atoms other than hydrogen atoms and n is 0 1, 2, 3 or 4 and 2 less than the valence of M,
And Y is an anionic or non-anionic ligand that binds to Z and M, contains a nitrogen, phosphorus, oxygen or sulfur atom and has up to 20 atoms other than hydrogen. , Or optionally Y and Z together form a fused ring system).

Specific compounds of the above catalyst complex include
(Tertiary butylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediyl zirconium dichloride, (tertiary butylamide) (tetramethyl-η
⁵ -cyclopentadienyl) -1,2-ethanediyl titanium dichloride, (methylamide) (tetramethyl-
η ⁵ -Cyclopentadienyl) -1,2-ethanediylzirconium dichloride, (methylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediyltitanium dichloride, (ethylamide) (tetramethyl- η ⁵ -cyclopentadienyl) methylene titanium dichloride, (tertiary butylamido) dibenzyl (tetramethyl-η ⁵ -cyclopentadienyl) silane zirconium dibenzyl, (benzylamido) dimethyl (tetramethyl-η ⁵ -cyclopentadiene (Phenyl) silane titanium dichloride, (phenylphosphide) dimethyl (tetramethyl-η ⁵ -cyclopentadienyl) silane zirconium dibenzyl, (tertiary butylamido) dimethyl (tetramethyl-η ⁵ -cyclopentadienyl) silane titanium dimethyl Etc. are examples It is.

The catalyst further contains an activating cocatalyst. As the cocatalyst, an aluminoxane having a high degree of polymerization or a low degree of polymerization, particularly methylaluminoxane is suitable. So-called modified methylaluminoxane is also suitable for use as the cocatalyst.

Polymerization of the ethylene-α-olefin copolymer in the present invention is preferably carried out by a solution polymerization method, and the conditions for a usual solution polymerization method can be directly adopted. That is, the polymerization temperature is 0 to 250 ° C., and the polymerization pressure is from normal pressure to 100 MPa. If necessary, the polymerization can be carried out according to a suspension method, a slurry method, a gas phase method or another method. Although a carrier can be used, preferably the catalyst is used in a homogeneous (eg soluble) state.
Of course, when the catalyst component and its co-catalyst component are added directly to the polymerization process and a suitable solvent or diluent (including concentrated monomer) is used in the polymerization process,
It is preferred that the active catalyst system is formed in the reactor. However, the active catalyst may be formed in a separate step in a suitable solvent prior to its addition to the polymerization mixture, which method is also preferred. In addition, ethylene-α
-For details of the method for producing an olefin copolymer, see JP-A-6-
No. 306121 and Japanese Patent Publication No. 7-500622.

The flame retardant used in the present invention is, for example, an organic halogen flame retardant, an organic phosphorus flame retardant, an inorganic flame retardant or the like.

Examples of organic halogen-based flame retardants are: hexabromobenzene, decabromodiphenyl oxide, polydibromophenylene oxide, bis (tribromophenoxy) ethane, ethylenebis pentabromobenzene, ethylenebis. Dibromonorbornane dicarboximide, ethylenebis tetrabromophthalimide, dibromoethyl dibromocyclohexane, dibromoneopentyl glycol, tribromophenol, tribromophenol allyl ether, tetrabromo bisphenol A derivative, tetrabromo bisphenol S, tetradecabromo Diphenoxybenzene, tris (2,3-dibromopropyl-
1) Isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxyethoxy-3,5-dibromophenyl) propane, pentabromophenol, pentabromo Toluene, pentabromodiphenyl oxide, hexabromocyclododecane, hexabromodiphenyl ether, octabromophenol ether, octabromodiphenyl ether, octabromodiphenyl oxide,
Dibromo neopentyl glycol tetracarbonate,
Bis (tribromophenyl) fumaramide, N-methylhexabromophenylamine, brominated epoxy resin, chlorinated paraffin, chlorinated polyolefin, chlorinated polyethylene, perchlorocyclopentadecane and the like.

Examples of the organophosphorus flame retardant include tris (chloroethyl) phosphate, tris (monochloropropyl) phosphate, tris (dichloropropyl) phosphate, triallyl phosphate, tris (3-hydroxypropyl) phosphine oxide, tris (tribromophenyl). ) Phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, glycidyl-α-methyl-β-di (butoxy) phosphinyl propionate, dibutylhydroxymethylphosphonate, di (butoxy) phosphinyl propylamide, Dimethylmethylphosphonate, ethylene bis tris (2-
Examples thereof include amine phosphates such as cyanoethyl) phosphonium bromide, ammonium polyphosphate, and ethylenediamine phosphate, and amine phosphates.

As the inorganic flame retardant, antimony trioxide, aluminum hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, calcium phosphate, zircon oxide, titanium oxide, zinc oxide, magnesium oxide,
Magnesium carbonate, calcium carbonate, barium sulfate, barium borate, barium metaborate, zinc borate, zinc metaborate, anhydrous alumina, molybdenum disulfide, clay,
Examples include red phosphorus, diatomaceous earth, kaolinite, montmorillonite, hydrotalcite, talc, silica, white carbon, zeolite, asbestos and lithopone. When using these inorganic flame retardants, the surface of the flame retardant is stearic acid, oleic acid, palmitic acid or other fatty acid or metal salt, paraffin, wax, or modified products thereof, organic silane, organic borane, organic titanate, etc. Surface treatment such as coating with is preferable.

The above flame retardants such as organic halogen flame retardants, organic phosphorus flame retardants and inorganic flame retardants may be used alone,
Needless to say, a plurality of combinations may be used.

The amount of the flame retardant compounded depends on the resin component (ethylene-
5 to 2 per 100 parts by weight of α-olefin copolymer)
50 parts by weight. This is because when the amount of the flame retardant compounded is less than 5 parts by weight, the flame retardancy is insufficient, while when it exceeds 250 parts by weight, not only the moldability is deteriorated, but also the mechanical properties and flexibility of the molded product are improved. And deterioration of low temperature characteristics and the like.

The flame-retardant ethylene resin composition of the present invention comprises
Various additives and auxiliary materials can be blended according to the purpose of use as long as the properties of the present invention are not impaired. As these various additives and auxiliary materials, stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, lubricants, processability improvers, fillers, dispersants, copper damage inhibitors, neutralizing agents. , A foaming agent, an air bubble inhibitor, a coloring agent, carbon black and the like. It is also possible to crosslink by adding a crosslinking agent for crosslinking, for example, an organic peroxide, sulfur or a silane-based crosslinking agent or a crosslinking aid, or to perform crosslinking by irradiation with ionizing radiation.

The flame-retardant ethylene resin composition of the present invention comprises
The ethylene-α-olefin copolymer and the flame retardant, if necessary, the above-mentioned various additives and auxiliary materials, cross-linking agent, etc. are blended,
Common methods, such as kneaders, Banbury mixers,
It can be produced by uniformly mixing and kneading with a continuous mixer or an extruder.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Some of the ethylene-α-olefin copolymers used in the present invention are sold as Affinity (registered trademark) by The Dow Chemical Company, USA. The resin is produced using a geometrically constrained catalyst, which is a kind of single-site catalyst, and has 0.01 to 100 carbon atoms in the main chain of the ethylene-α-olefin copolymer per 1,000 carbon atoms. It contains long chain branches in a ratio of three. Since it contains this long-chain branch, the workability is good even though Mw / Mn is small. The small molecular weight distribution means that the mechanical properties are excellent. Conventionally, ethylene-α-
Among the olefin copolymers, those having a small molecular weight distribution, that is, those having excellent mechanical properties were inferior in processability, but the above resin in the present invention is excellent in both mechanical properties and processability, and has an extremely low By selecting one having a high density, even a large amount of flame retardant can be uniformly dispersed and retained in the ethylene-α-olefin copolymer.

[0020]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Ethylene-α-olefin copolymer produced by using a single-site catalyst [ethylene-octene having a density of 0.900 g / cm ³ , a melt flow rate of 0.8 g / 10 minutes and Mw / Mn 2.4] -1 copolymer, Affinity (registered trademark), manufactured by The Dow Chemical Co., Ltd.] 100 parts by weight and 120 parts by weight of magnesium hydroxide were kneaded in a Banbury mixer at 160 ° C for 10 minutes, and then granulated into pellets, Using the pellets, 150 by a hot press molding machine
A sheet having a thickness of 1 mm and a sheet having a thickness of 3 mm is obtained by molding at 100 ° C. and 100 kg / cm ² for 3 minutes. Using the sheet, a flame retardancy test, a tensile test and an elongation test are performed under the following conditions. The results are shown in Table 1.

Test Conditions (1) Flame Retardancy Test A sheet having a thickness of 3 mm is used, and JIS K720 is used.
It does based on 1. The results are expressed as oxygen indices, the higher the value, the better the flame retardancy. (2) Tensile test, elongation test A sheet with a thickness of 1 mm is used, and JIS K676 is used.
Perform according to 0.

Examples 2 to 6 and Comparative Examples 1 to 8 Using the compositions having the compositions shown in Table 1, the same operation as in Example 1 is repeated. The respective results are summarized in Table 1.

[0024]

[Table 1] (Footnote in Table 1) * 1 Ethylene-α-olefin copolymer A = ethylene-octene-1 copolymer produced using a single-site catalyst [density 0.900 g / cm ³ , melt flow rate 0.8 g / 10 minutes, Mw / Mn 2.4, Affinity (registered trademark), manufactured by The Dow Chemical Co., Ltd.] * 2 Ethylene-α-olefin copolymer B = ethylene-butene-1 copolymer produced using a Ziegler-based catalyst [Density 0.900 g / cm ³ , melt flow rate 0.8 g / 10 minutes, Mw / Mn 3.3, Nakflex (registered trademark), manufactured by Nippon Unicar Co., Ltd.] * 3 Ethylene-α-olefin copolymer C = Ziegler ethylene was produced using a system catalyst - butene-1 copolymer [density 0.920 g / cm ^3, melt flow rate 1.0 g / 10 min, Mw / Mn3.3, N C polyethylene LL (trade name), manufactured by Nippon Unicar Company Limited] * 4 high-pressure low-density polyethylene = density 0.920g /
cm ^3, a melt flow rate 0.7 g / 10 min polyethylene [NUC Polyethylene (trade name), Nippon Unicar Co., Ltd.] * 5 ethylene - vinyl acetate copolymer = melt flow rate 1.5 g / 10 min, a comonomer content 18% by weight of ethylene-vinyl acetate copolymer [NUC-EVA copolymer (trade name), manufactured by Nippon Unicar Co., Ltd.] * 6 Ethylene-ethyl acrylate copolymer = melt flow rate 1.5 g / 10 minutes, comonomer content 15% by weight of ethylene-ethyl acrylate copolymer [NUC-
EEA copolymer (trade name), manufactured by Nippon Unicar Co., Ltd.

From the results shown in Table 1, the following is clear. First, all the examples of the present invention have excellent flame retardancy and mechanical properties. In contrast, Comparative Examples 1 to 6 are inferior in mechanical properties to Examples 1 to 6. This is due to the fact that in the above comparative example, a resin other than the ethylene resin used in the present invention is used. Further, although Comparative Examples 7 and 8 use the ethylene-based resin used in the present invention, Comparative Example 7 is inferior in flame retardancy due to an excessively small amount of the flame retardant compounded, and Comparative Example 8 is conversely flame retardant. The mechanical properties are inferior because of the excessive amount.

[0026]

As described in detail above, the flame-retardant ethylene-based resin composition of the present invention has very excellent mechanical properties because the ethylene-based resin used has a narrow molecular weight distribution. Moreover, since the main chain contains a certain amount of long chain branches, it has excellent processability. Furthermore, the density is extremely low, which is classified as ultra-low density, so a large amount of flame retardant is evenly dispersed and retained. can do. Therefore, the flame-retardant ethylene-based resin composition of the present invention is excellent in various properties such as flame retardancy, processability, low temperature properties, environmental stress cracking properties, insulation properties, and mechanical properties of conventional flame-retardant ethylene resins. This is a marked improvement over the resin composition. The flame-retardant ethylene-based resin composition having such excellent properties, particularly excellent workability and mechanical properties, is a material extremely suitable for coating electric wires and the like.

Claims (2)

[Claims] 1. A melt flow rate of 0.5 to 50 g / 1.
0 minutes, density 0.86 to 0.91 g / cm ³ and ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw
/ Mn) 3.0 or less, consisting of 100 parts by weight of a substantially linear ethylene-α-olefin copolymer produced using a single-site catalyst, and 5 to 250 parts by weight of a flame retardant. A flame-retardant ethylene-based resin composition characterized by the above. 2. An α of an ethylene-α-olefin copolymer
-The flame-retardant ethylene-based resin composition according to claim 1, wherein the olefin is octene-1.