JP5827139B2 - Flame retardant resin composition, method for producing the same, molded product thereof, and electric wire - Google Patents

Description

  The present invention relates to a flame retardant resin composition excellent in the balance of mechanical strength, flexibility and flame retardancy, a method for producing the same, and a molded body and an electric wire obtained using the flame retardant resin composition.

  A propylene-based polymer is a material excellent in heat resistance, mechanical strength, and scratch resistance, and the molded body is used for a wide range of applications. A molded body obtained from a resin composition comprising general polypropylene and an inorganic filler is also excellent in heat resistance and mechanical strength, but on the other hand, it is inferior in flexibility and impact resistance. Therefore, ethylene-based copolymers have been mainly used for applications that require characteristics such as flexibility and impact resistance. However, molded articles obtained from ethylene copolymers are inferior in scratch resistance and heat resistance.

  Then, the molded object which consists of a propylene-type polymer and an inorganic type filler (flame retardant) is known as an electric wire or a wire harness in which scratch resistance is requested | required (patent document 1). In addition, it is known that a propylene / butene copolymer, polyethylene and an inorganic filler are blended with polypropylene (Patent Document 2). In addition, it is known that an ethylene / α-olefin random copolymer elastomer or a styrene elastomer is blended with a propylene polymer together with an inorganic filler (Patent Document 3). Furthermore, compositions in which polypropylene, maleic acid-modified polyethylene and metal hydrate are blended with an ethylene / vinyl acetate copolymer are known (Patent Documents 4 to 8).

  As described above, various improvements have been proposed, but more excellent performance is required in the balance of mechanical strength, flexibility, and flame retardancy.

JP 2003-313377 A JP 2008-97918 A JP 2008-169257 A JP 2008-94977 A JP 2009-114230 A JP 2009-54388 A JP 2009-19190 A JP 2009-216836 A

  An object of the present invention is to provide a flame retardant resin composition having an excellent balance of mechanical strength, flexibility and flame retardancy, a method for producing the same, and a molded body obtained using the flame retardant resin composition (for example, insulation). A body and a sheath) and an electric wire.

  The present invention uses a combination of a copolymer of ethylene and a vinyl ester compound and a specific propylene polymer, so that metal hydroxide uptake, that is, metal hydroxide in a flame retardant resin composition can be obtained. This is based on the finding that a flame retardant resin composition having good dispersibility of the product and excellent balance of mechanical strength, flexibility and flame retardancy can be obtained. Furthermore, it is based on the finding that by using such a specific flame retardant resin composition, a molded article having an excellent balance of mechanical strength, flexibility and flame retardancy can be obtained.

That is, the present invention
As a polymer component,
Copolymer of ethylene and vinyl ester (A) 50 to 95% by mass,
5 to 50% by mass of a propylene-based copolymer (B) having an α-olefin content other than propylene of 10 to 60 mol%, and
Polypropylene (C) having a content of α-olefin other than propylene of less than 10 mol%, 0 to 40% by mass
[Total 100% by mass of components (A), (B) and (C)]
Containing
Furthermore, for a total of 100 parts by mass of the components (A), (B) and (C),
100 to 150 parts by mass of metal hydroxide (D), and
Containing 20 to 40 parts by mass of expanded graphite (E),
It is a flame retardant resin composition in which the total amount of components (D) and (E) is 140 parts by mass or more with respect to 100 parts by mass in total of components (A), (B), and (C) .

The present invention is also a method for producing the flame retardant resin composition,
A step of producing a polymer composition (G) by melt-kneading a polymer component containing at least a copolymer of ethylene and vinyl ester (A) and a propylene-based copolymer (B);
It is a method for producing a flame-retardant resin composition, comprising a step of melt-kneading at least a polymer composition (G), a metal hydroxide (D), and expanded graphite ( E ).

  Moreover, this invention is an electric wire which has the molded object which consists of said flame-retardant resin composition, and the insulator and / or electric wire sheath which are this molded object.

  The flame retardant resin composition of the present invention has excellent performance in the balance of mechanical strength, flexibility and flame retardancy, and can be suitably used for a wide range of molded articles, particularly electric wires.

[Copolymer of ethylene and vinyl ester (A)]
The copolymer (A) of ethylene and vinyl ester used in the present invention is a polymer obtained by copolymerizing at least ethylene and vinyl ester. It may be a binary copolymer obtained by copolymerizing only ethylene and vinyl ester, and other monomers (other polar monomers) as long as the performance of the binary copolymer is not impaired. ) And a terpolymer or more copolymer obtained by copolymerization.

  Specific examples of the vinyl ester used for the copolymer (A) include vinyl acetate and vinyl propionate. Of these, vinyl acetate is preferred.

  Other monomers used in the copolymer (A) include acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n-propyl, isobutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, glycidyl methacrylate, dimethyl maleate, maleic acid Diethyl is mentioned. A small amount of carbon monoxide can be copolymerized.

  The proportion of the structural unit derived from vinyl ester is usually 5 to 70% by weight, preferably 10 to 60% by weight in the total 100 mass% of the structural unit derived from ethylene and the structural unit derived from vinyl ester in the copolymer (A). %, More preferably 19 to 50% by weight. These ranges are significant in terms of the balance between mechanical strength and flame retardancy. In particular, the lower limit value is significant in terms of flame retardancy, and the upper limit value is significant in terms of mechanical strength.

  From the viewpoint of physical properties and workability of the composition, the melt flow rate of the copolymer (A) (conforming to JIS K7210-99, temperature 190 ° C., load 2160 g) is preferably 0.1 to 50 g / 10 min, more preferably. Is 0.5 to 10 g / 10 min.

  The copolymer (A) can be obtained, for example, by radical copolymerization of ethylene and vinyl ester under high temperature and high pressure. In particular, when polymerized by a high-pressure radical polymerization process by an autoclave method, a copolymer having good randomness can be obtained.

[Propylene copolymer (B)]
The propylene-based copolymer (B) used in the present invention is a propylene-based copolymer having a content of α-olefin other than propylene of 10 to 60 mol%. Here, the content of α-olefin other than propylene specifically means the proportion of constituent units derived from α-olefin other than propylene in 100 mol% of all constituent units of propylene-based copolymer (B). The propylene-based copolymer (B) is typically composed of a structural unit derived from propylene and another structural unit derived from α-olefin, and other copolymer components (other non-conjugates). Constituent units derived from diene or the like are substantially not included.

  As the propylene-based copolymer (B), for example, a random copolymer or a block copolymer obtained by copolymerizing propylene and at least one olefin having 2 to 20 carbon atoms other than propylene is used. be able to. Specific examples of the α-olefin having 2 to 20 carbon atoms other than propylene include ethylene; 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, Examples thereof include α-olefins having 4 to 10 carbon atoms such as 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene.

  In 100 mol% of the propylene-based copolymer (B), the proportion of the structural unit derived from propylene is 40 to 90 mol%, preferably 40 to 85 mol%, more preferably 40 to 80 mol%, particularly preferably. 50 to 75 mol%. Moreover, the ratio of the structural unit derived from (alpha) -olefins other than propylene is 10-60 mol%, Preferably it is 15-60 mol%, More preferably, it is 20-60 mol%, Most preferably, it is 25-50 mol%. is there.

  The melt flow rate (according to ASTM D1238, temperature 230 ° C., load 2.16 kg) of the propylene-based copolymer (B) is preferably 0.1 to 50 (g / 10 min).

  The propylene-based copolymer (B) has a melting point measured by differential scanning calorimetry (DSC) of less than 120 ° C. or no melting point is observed, and preferably has a melting point of 100 ° C. or lower, or No melting point is observed. Here, that the melting point is not observed means that a crystal melting peak having a heat of crystal melting of 1 J / g or more is not observed in the range of −150 to 200 ° C. The measurement conditions are as described in the examples.

  The intrinsic viscosity [η] of propylene copolymer (B) measured in decalin at a temperature of 135 ° C. is usually 0.01 to 10 dl / g, preferably 0.05 to 10 dl / g.

The propylene-based copolymer (B) preferably has a triad tacticity (mm fraction) measured by ¹³ C-NMR of 85% or more, more preferably 85 to 97.5%, still more preferably 87 to 97. %, Particularly preferably in the range of 90 to 97%. When the triad tacticity (mm fraction) is in this range, the balance between flexibility and mechanical strength is particularly excellent, which is suitable for the present invention. The mm fraction can be measured by the method described in International Publication No. 2004-087775 pamphlet, page 21, line 7 to page 26, line 6.

  The production method of the propylene-based copolymer (B) is not particularly limited. For example, a known catalyst capable of stereoregular polymerization of an olefin with an isotactic structure or a syndiotactic structure, for example, a catalyst mainly composed of a solid titanium component and an organometallic compound, or a metallocene compound as one component of the catalyst. It can be obtained by copolymerizing propylene and other α-olefins in the presence of the metallocene catalyst used. Further, it can be obtained by copolymerizing propylene and another α-olefin using a known catalyst capable of polymerizing olefin with an atactic structure. Preferably, as described later, it is obtained by copolymerizing propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene) in the presence of a metallocene catalyst.

  Specific examples of the propylene copolymer (B) include propylene / ethylene / α-olefin random copolymer (B-1) having 4 to 20 carbon atoms, and α-olefin having 4 to 20 propylene / carbon atoms. A random copolymer (B-2) is mentioned. By using these copolymers (B-1) or (B-2), for example, compatibility with a crystal component contained in polypropylene (C) is exhibited, and flame retardancy superior in tensile elongation and flexibility is exhibited. A resin composition is obtained. Hereinafter, the copolymers (B-1) and (B-2) will be described.

[Propylene / ethylene / α-olefin random copolymer having 4 to 20 carbon atoms (B-1)]
The propylene / ethylene / α-olefin random copolymer (B-1) having 4 to 20 carbon atoms is a copolymer of propylene, ethylene and at least one of α-olefins having 4 to 20 carbon atoms. It is a coalescence. Specific examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, -Tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene. Of these, 1-butene and 1-octene are preferable.

The copolymer (B-1) satisfies the following conditions (m) and (n).
(M) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 1-3.
(N) 40 to 85 mol% of propylene-derived structural units, 5 to 30 mol% of structural units derived from ethylene, and 5 to 30 mol% of structural units derived from α-olefins having 4 to 20 carbon atoms ( Here, the total of the structural unit derived from propylene, the structural unit derived from ethylene, and the structural unit derived from α-olefin having 4 to 20 carbon atoms is 100 mol%, and the structural unit derived from ethylene and the number of carbon atoms. The total of the structural units derived from 4 to 20 α-olefin is preferably 15 to 60 mol%.)

  More specifically, when the total of the structural unit derived from propylene, the structural unit derived from ethylene, and the structural unit derived from α-olefin having 4 to 20 carbon atoms is 100 mol%, the proportion of the structural unit derived from propylene is as follows: Preferably it is 60-82 mol%, More preferably, it is 61-75 mol%, Preferably the structural unit derived from ethylene is 8-15 mol%, More preferably, it is 10-14 mol%, and C4-C4 The proportion of the structural unit derived from 20 α-olefin is preferably 10 to 25 mol%, more preferably 15 to 25 mol%.

The copolymer (B-1) preferably satisfies at least one of the following conditions (o) and (p), more preferably both.
(O) Shore A hardness is 30-90.
(P) The degree of crystallinity measured by X-ray diffraction is 20% or less, preferably 10% or less.

  The melting point Tm measured by DSC of the copolymer (B-1) is preferably 50 ° C. or lower, or it is desirable that no melting point is observed. More preferably, no melting point is observed. The melting point Tm of the copolymer (B-1) is measured by DSC as follows. In the measurement, the sample was packed in an aluminum pan, heated to 200 ° C. at 100 ° C./min, held at 200 ° C. for 5 minutes, then cooled to −150 ° C. at 10 ° C./min, and then at 200 ° C./min The temperature of the endothermic peak observed when the temperature is raised to ° C. is the melting point Tm. The melting point Tm is usually less than 120 ° C, preferably 100 ° C or less, more preferably 40 to 95 ° C, and particularly preferably 50 to 90 ° C. When the melting point Tm is within this range, a molded article having an excellent balance between flexibility and strength can be obtained. Moreover, since the stickiness of the surface of a molded object is suppressed, it becomes easy to construct a molded object.

  Such a copolymer (B-1) is obtained, for example, by the method described in International Publication No. 2004/87775 pamphlet.

  In the present invention, by using the above-described copolymer (B-1), a molded article with improved flexibility and large tensile elongation can be obtained. For example, in the case where the molded body is an electric wire, there is an advantage that the electric wire coating is not easily broken when a force is applied.

[Propylene / α-olefin random copolymer having 4 to 20 carbon atoms (B-2)]
The propylene / α-olefin random copolymer (B-2) having 4 to 20 carbon atoms is a copolymer of propylene and at least one kind of α-olefin having 4 to 20 carbon atoms. Specific examples of the α-olefin having 4 to 20 carbon atoms include the same as in the case of the copolymer (B-1). 1-butene is particularly preferable.

The copolymer (B-2) satisfies the following conditions (a) and (b).
(A) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 1-3.
(B) the melting point Tm (° C.) and the comonomer constituent unit content M (mol%) determined by ¹³ C-NMR spectrum measurement,
146 exp (−0.022 M) ≧ Tm ≧ 125 exp (−0.032 M)
(However, Tm is less than 120 ° C., preferably 100 ° C. or less).

  The melting point Tm of the copolymer (B-2) can be measured by the same method as in the case of the copolymer (B-1).

The copolymer (B-2) preferably satisfies the following condition (c).
(C) The crystallinity measured by X-ray diffraction is 40% or less, more preferably 35% or less.

  When the total of the structural unit derived from propylene of the copolymer (B-2) and the structural unit derived from α-olefin having 4 to 20 carbon atoms is 100 mol%, the α-olefin having 4 to 20 carbon atoms. The ratio of the derived structural unit is preferably 10 to 50 mol%, more preferably 10 to 35 mol%.

  Such a copolymer (B-2) can be obtained, for example, by the method described in JP-A-2007-186665.

[Polypropylene (C)]
The polypropylene (C) used in the present invention is a polypropylene having an α-olefin content other than propylene of less than 10 mol%. Here, the content of α-olefin other than propylene specifically means the proportion of constituent units derived from α-olefin other than propylene in 100 mol% of all constituent units of polypropylene (C). Polypropylene (C) is typically composed of propylene-derived constitutional units and optionally α-olefin-derived constitutional units other than propylene, and other copolymer components (other non-conjugated dienes and the like). ) -Derived structural unit is not substantially contained.

  Examples of polypropylene (C) include not only a propylene homopolymer but also a copolymer of propylene and at least one α-olefin having 2 to 20 carbon atoms other than propylene. Specific examples of the α-olefin having 2 to 20 carbon atoms other than propylene include the same as in the case of the propylene-based copolymer (B), and the preferred range is also the same. These α-olefins may form a random copolymer with propylene or a block copolymer. These α-olefin-derived structural units may be contained in the total structural unit of polypropylene (C) in a proportion of less than 10 mol%, preferably 5 mol% or less.

  According to ASTM D 1238 of polypropylene (C), the melt flow rate (MFR) measured at a temperature of 230 ° C. and a load of 2.16 kg is usually 0.01 to 1000 g / 10 minutes, preferably 0.05 to 100 g. / 10 minutes, more preferably 0.1 to 50 g / 10.

  The melting point of the polypropylene (C) measured by a differential scanning calorimeter (DSC) is preferably 120 to 170 ° C, more preferably 125 to 165 ° C.

  Polypropylene (C) may have either an isotactic structure or a syndiotactic structure. However, an isotactic structure is preferable from the viewpoint of heat resistance and the like.

  As polypropylene (C), a plurality of types of polypropylene can be used in combination as required. For example, two or more types of polypropylene having different melting points and rigidity can be used in combination.

  As polypropylene (C), homopolypropylene having excellent heat resistance (usually known as a copolymer component other than propylene of 3 mol% or less), block polypropylene having a good balance between heat resistance and impact resistance (usually 3 to 3%) A known polypropylene having 30% by mass of n-decane eluting component), or a random polypropylene having a good balance between flexibility and transparency (usually a melting peak temperature measured by a differential scanning calorimeter (DSC) of 120 ° C. or higher, A known material preferably in the range of 125 ° C. to 150 ° C. may be selected and used in order to obtain the desired physical properties. These can also be used in combination.

  Such a polypropylene (C) is, for example, a solid catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, a Ziegler catalyst system comprising an organoaluminum compound and an electron donor, or a metallocene compound as a catalyst. Using the metallocene catalyst system used as a component, it can be produced by polymerizing propylene or copolymerizing propylene and other olefins.

[Metal hydroxide (D)]
The metal hydroxide (D) used in the present invention is not particularly limited as long as it is a metal hydroxide. Specific examples thereof include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, manganese hydroxide, zinc hydroxide, and hydrotalcite. These can be used singly or as a mixture of two or more. In particular, it is preferable to use one or more metal hydroxides selected from the group consisting of magnesium hydroxide, aluminum hydroxide, and hydrotalcite. Of these, magnesium hydroxide alone, a mixture of magnesium hydroxide and a metal hydroxide other than magnesium hydroxide, aluminum hydroxide alone, a mixture of aluminum hydroxide and a metal hydroxide other than aluminum hydroxide are preferred, and magnesium hydroxide Alone, aluminum hydroxide, and a mixture of magnesium hydroxide and aluminum hydroxide are more preferred. For example, as a commercial product of magnesium hydroxide, there is a trade name Magnifin (registered trademark) H5IV manufactured by Albemarle. As commercial products of aluminum hydroxide, there are trade name Hygilite (registered trademark) HS-330 manufactured by Showa Denko KK and trade name CL-303 manufactured by Sumitomo Chemical Co., Ltd.

  The average particle diameter of the metal hydroxide (D) is usually from 0.05 to 20 μm, preferably from 0.1 to 5 μm.

  The metal hydroxide (D) is preferably a metal hydroxide whose surface is treated with a surface treatment agent in order to improve dispersibility in the composition. Specific examples of the surface treatment agent include alkalis of higher fatty acids such as sodium caprate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, potassium stearate, sodium oleate, potassium oleate, and sodium linoleate. Metal salts; higher fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid; fatty acid amides; fatty acid esters; higher aliphatic alcohols; isopropyl triisostearoyl titanate, isopropyl tris (dioctyl borophosphate) ) Titanium coupling agents such as titanate, tetraisopropylbis (dioctyl phosphite) titanate; vinyltrimethoxysilane, vinyltriethoxysilane, γ-metac Le trimethoxysilane, silane coupling agents such as γ- glycidoxypropyltrimethoxysilane; silicone oil; various phosphates. For example, a commercial product of magnesium hydroxide surface-treated with a higher fatty acid is trade name Kisuma (registered trademark) 5B manufactured by Kyowa Chemical Co., Ltd.

  The compounding ratio of the metal hydroxide (D) is 50 to 350 parts by mass, preferably 150 to 300 parts by mass with respect to 100 parts by mass in total of the components (A), (B), and (C). By setting the blending ratio within these ranges, it is possible to balance the flame retardancy, tensile elongation and flexibility of the flame retardant resin composition.

[Expanded graphite (E)]
The expanded graphite (E) used in the present invention is not particularly limited, but for example, one obtained by inserting sulfuric acid between layers of flake graphite and neutralizing it is preferable. For example, commercially available products of expanded graphite include trade name Moehen Z (registered trademark) MZ-285 manufactured by Air Water Co., Ltd., trade names SYZR501, SYZR502, SYZR503, SYZR801, SYZR802, and SYZR803 manufactured by Sanyo Trading Co., Ltd. SYZR1002, a trade name GREP-EG which is a heat-expandable graphite manufactured by Suzuhiro Chemical Co., Ltd.

  The mixing ratio of the expanded graphite (E) is 0.1 to 50 parts by mass with respect to 100 parts by mass in total of the components (A), (B) and (C).

[Ethylene / α-olefin copolymer (F)]
The flame retardant resin composition of the present invention may further contain an ethylene / α-olefin copolymer (F) in addition to the components described above.

  The ethylene / α-olefin copolymer (F) is not particularly limited, but a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms is preferable. Specific examples of the α-olefin having 3 to 10 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, and 3-ethyl-1. -Pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1 -Decene is mentioned. One of these may be used alone, or two or more may be used in combination. Of these, propylene, 1-butene, 1-hexene and 1-octene are preferable.

  In 100 mol% of all the structural units of the copolymer (F), the content of structural units derived from ethylene is 75 to 95 mol%, and the content of structural units derived from α-olefin is 5 to 25 mol%. It is preferable.

The density of the copolymer (F) is preferably 0.855 to 0.910 g / cm ³ , more preferably 0.857 to 0.890 g / cm ³ .

The melt flow rate (MFR ₂ ) at a temperature of 190 ° C. and a load of 2.16 kg of the copolymer (F) is preferably 0.1 to 100 g / 10 minutes, more preferably 0.1 to 20 g / 10 minutes.

  The molecular weight distribution (Mw / Mn) evaluated by the GPC method of the copolymer (F) is preferably 1.5 to 3.5, more preferably 1.5 to 3.0, and particularly preferably 1.8 to 2.5. Here, Mw represents a weight average molecular weight, and Mn represents a number average molecular weight.

B value determined from ¹³ C-NMR spectrum and the following formula of the copolymer (F) is preferably from 0.9 to 1.5, more preferably 1.0 to 1.2.

B value = [P _OE ] / (2 · [P _E ] [P _O ])
(Wherein [P _E ] is the mole fraction of structural units derived from ethylene in the copolymer, and [P _O ] is the content of structural units derived from α-olefin in the copolymer) (Mole fraction, [P _OE ] is the ratio of the number of ethylene / α-olefin chains to the total dyad chains in the copolymer).
This B value is an index representing the distribution state of ethylene and α-olefin in the ethylene / α-olefin copolymer. The larger the B value, the shorter the block chain of ethylene or α-olefin, the more uniform the distribution of ethylene and α-olefin, and the narrower the composition distribution of the copolymer rubber. Further, as the B value becomes smaller than 1.0, the composition distribution of the ethylene / α-olefin copolymer becomes wider and the handling property tends to be lowered. This B value can be obtained based on reports of JCRandall (Macromolecules, 15, 353 (1982)), J.Ray (Macromolecules, 10, 773 (1977)) and the like.

The intensity ratio (Tαβ / Tαα) of Tαβ to Tαα in the ¹³ C-NMR spectrum of the copolymer (F) is preferably 0.5 or less, more preferably 0.4 or less, and particularly preferably 0.3 or less. . Tαα and Tαβ are the peak intensities of CH ₂ in a structural unit derived from an α-olefin having 3 or more carbon atoms, and mean two types of CH ₂ having different positions relative to the tertiary carbon as shown below. ing.

This intensity ratio (Tαβ / Tαα) can be obtained as follows. First, the ¹³ C-NMR spectrum of the ethylene / α-olefin copolymer (F) is measured using an NMR measuring apparatus (for example, JEOL-GX270 manufactured by JEOL Ltd.). This measurement was performed using a mixed solution of hexachlorobutadiene / d6-benzene = 2/1 (volume ratio) adjusted to a sample concentration of 5% by weight, 67.8 MHz, 25 ° C., d6-benzene (128 ppm). Perform under standard conditions. Then, the ¹³ C-NMR spectrum is analyzed according to the proposal of Lindeman Adams (Analysis Chemistry 43, p1245 (1971)) and JCRandall (Review Macromolecular Chemistry Physics, C29, 201 (1989)) to obtain the intensity ratio (Tαβ / Tαα). .

Ratio of melt flow rate (MFR ₁₀ ) at a temperature of 190 ° C. and a load of 10 kg of the copolymer (F) to a melt flow rate (MFR ₂ ) at a temperature of 190 ° C. and a load of 2.16 kg (MFR ₁₀ / MFR ₂ ) Preferably satisfies the following relationship.

MFR ₁₀ / MFR ₂ ≧ 5.7
Mw / Mn + 4.7 ≦ MFR ₁₀ / MFR ₂
Each of the above relationships is significant in terms of formability and material strength.

  Such an ethylene / α-olefin copolymer (F) can be obtained, for example, by copolymerizing ethylene and an α-olefin in the presence of a specific catalyst. As the catalyst, for example, a Ziegler catalyst or a metallocene catalyst composed of a vanadium compound and an organoaluminum compound can be used. A metallocene catalyst is particularly preferable.

  The metallocene-based catalyst may be composed of, for example, a metallocene compound (a) and a compound (c) that reacts with the organoaluminum oxy compound (b) and / or the metallocene compound (a) to form an ion pair. . Furthermore, you may be comprised from the component (a), the component (b) and / or (c), and the organoaluminum compound (d). The copolymerization reaction can be carried out by any of batch, semi-continuous and continuous methods in the liquid phase using a hydrocarbon solvent in the presence of a catalyst. In the copolymerization, a molecular weight regulator such as hydrogen can also be used.

  When a metallocene catalyst composed of component (a) and component (b) or (c) is used, the concentration of component (a) in the polymerization system is usually from 0.00005 to 0.1 mmol / liter (polymerization). Volume), preferably 0.0001 to 0.05 mmol / liter (polymerization volume). Further, the component (b) is supplied in such an amount that the molar ratio of the aluminum atom to the transition metal (Al / transition metal) in the metallocene compound (a) in the polymerization system is 1 to 10,000, preferably 10 to 5,000. good. The component (c) may be supplied in such an amount that the molar ratio (c / a) of the component (c) to the component (a) is 0.5 to 20, preferably 1 to 10. The component (d) is usually used at 0 to 5 mmol / liter (polymerization volume), preferably 0 to 2 mmol / liter (polymerization volume).

The reaction temperature in the copolymerization reaction is usually −20 ° C. to 150 ° C., preferably 0 ° C. to 120 ° C., more preferably 0 ° C. to 100 ° C., and the reaction pressure exceeds 0 and is 7.8 MPa (80 kgf / cm ² , gauge pressure) or less, preferably more than 0 and 4.9 MPa (50 kgf / cm ² , gauge pressure) or less.

  The ethylene / α-olefin copolymer (F) may be modified by grafting a vinyl compound having a polar group. Specific examples of vinyl compounds having a polar group include vinyl compounds having oxygen-containing groups such as acids, acid anhydrides, esters, alcohols, epoxies, and ethers; vinyl compounds having nitrogen-containing groups such as isocyanates and amides; And vinyl compounds having a silicon-containing group. The grafting amount of the vinyl compound having a polar group is usually 0.01 to 10% by mass, preferably 0.05 to 5% by mass, when the mass of the ethylene / α-olefin copolymer after grafting is 100% by mass. %.

[Flame-retardant resin composition]
The flame retardant resin composition of the present invention contains the components (A) to (E) described above and, if desired, the component (F) and other components as required, and is V-0 defined by the UL94 standard. , V-1 and V-2 in the test, when the sample thickness is 1 mm or less, the composition becomes V-0 rank.

  In a total of 100% by mass of the components (A), (B) and (C), the proportion of the copolymer (A) is 50 to 95% by mass, preferably 55 to 90% by mass. Moreover, the ratio of a propylene-type copolymer (B) is 5-50 mass%, Preferably it is 5-40 mass%. If the proportion of the propylene-based copolymer (B) is too high, the flame retardancy decreases. Moreover, the ratio of a polypropylene (C) is 0-40 mass%, Preferably it is 0-35 mass%, More preferably, it is 0-30 mass%. When the proportion of polypropylene (C) is too high, flexibility, tensile elongation, and flame retardancy are reduced.

  Furthermore, the ratio of the metal hydroxide (D) is 50 to 350 parts by mass, preferably 50 to 300 parts by mass, with respect to 100 parts by mass in total of the components (A), (B) and (C). Preferably it is 100-300 mass parts. The ratio of the expanded graphite (E) is 0.1 to 50 parts by mass, preferably 5 to 50 parts by mass, and more preferably 10 to 45 parts by mass.

  When the ethylene / α-olefin copolymer (F) is used in combination, the proportion is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass in total of the components (A), (B) and (C). More preferably, it is 1-25 mass parts, Most preferably, it is 3-25 mass parts.

When the whole flame-retardant resin composition is 100% by mass, the ratio of the total amount of the components (A) to (F) is preferably 60 to 100% by mass, more preferably 80% to 100% by mass. is there. When the total amount of the components (A) to ( F ) is not 100% by mass, the balance is, for example, other synthetic resins, other rubbers, or other additives. These are components to be blended as necessary within the range not impairing the object of the present invention.

  Other synthetic resins and other rubbers include, for example, polyolefin waxes such as polyethylene wax and polypropylene wax, low density polyethylene, medium density polyethylene, and LLDPE comprising a copolymer of ethylene and an α-olefin having 4 to 10 carbon atoms. (Linear low density polyethylene), ethylene elastomer, and styrene elastomer.

  Additives include, for example, antioxidants, heat stabilizers, UV absorbers, weathering stabilizers, antistatic agents, slip agents, antiblocking agents, crystal nucleating agents, pigments, dyes, lubricants, hydrochloric acid absorbers, copper damage An inhibitor. Furthermore, flame retardant imparting agents (flame retardants, flame retardant aids) other than components (D) and (E) can be used in combination.

  Specific examples of flame retardants include bromine-based flame retardants; phosphorus-based flame retardants such as red phosphorus, phosphate esters, phosphate amides, and organic phosphine oxides; ammonium polyphosphate, phosphazene , Triazine, melamine cyanurate and other nitrogen flame retardants; polystyrene salt sulfonate alkali metal salts, etc .; inorganic flame retardants such as zinc stannate; silicone oils, etc. Silicone flame retardant imparting agents may be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  As the nitrogen flame retardant imparting agent, a compound having a triazine ring is preferable. Specific examples include melamine, ammelin, melam, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, melamine pyrophosphate, butylene diguanamine, norbornene guanamine, methylene dimelamine, ethylene dimelamine, trimethylene dimelamine , Tetramethylene dimelamine, hexamethylene dimelamine, 1,3-hexylene dimelamine. Of these, melamine cyanurate is preferable. The compounding amount of the compound containing a triazine ring is preferably 0.1 to 50 parts by weight, more preferably 5 to 40 parts by weight with respect to 100 parts by weight of the total of components (A), (B) and (C). It is. The lower limit of these ranges is significant in that a combustion inert gas (nitrogen gas) is sufficiently generated from a compound having a triazine ring to obtain a synergistic effect with other flame retardancy-imparting agents. The upper limit is significant in terms of moldability and mechanical properties.

Specific examples of the inorganic flame retardant imparting agent include antimony compounds such as antimony trioxide, antimony pentoxide, and sodium antimonate; zinc compounds such as zinc sulfate, zinc stannate, and zinc hydroxystannate; Iron compounds such as iron and ferric oxide, tin compounds such as metastannic acid, stannous oxide and stannic oxide; tungsten compounds such as metal salts of tungstic acid and complex oxide acids of tungsten and metalloid; zirconium series Compound; hydrotalcite. These may be surface-treated with a fatty acid or a silane coupling agent. From the viewpoint of flame retardancy, zinc compounds are preferred, and zinc stannate and zinc hydroxystannate are particularly preferred. When these are blended, the speed of shell formation during combustion increases and the shell formation becomes stronger. The average particle diameter of zinc compounds (particularly zinc stannate and zinc hydroxystannate) is preferably 5 μm or less, more preferably 3 μm or less. Commercially available products of zinc stannate (ZnSnO ₃ ) and zinc hydroxystannate (ZnSn (OH) ₆ ) include, for example, trade names Alcanex ZS and Alcanex ZHS manufactured by Mizusawa Chemical.

Examples of the silicone flame retardant imparting agent include silicone resins and silicone oils. Examples of the silicone resin include resins having a three-dimensional network structure formed by combining structural units of SiO ₂ , RSiO _3/2 , R ₂ SiO, and R ₃ SiO _1/2 . Here, R represents an alkyl group such as a methyl group, an ethyl group, or a propyl group, an aromatic group such as a phenyl group or a benzyl group, or an alkyl group or an aromatic group having a vinyl group. Specific examples include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, modified silicone oils such as epoxy modification, alkyl modification, amino modification, carboxy modification, alcohol modification, and ether modification, dimethylpolysiloxane rubber, and methylvinylpolysiloxane. Examples thereof include silicone rubber such as rubber, silicone resin such as methyl silicone resin and ethyl silicone resin, and particulate silicone powder.

  The Shore D hardness of the flame retardant resin composition is preferably 60 or less.

  The flame retardant resin composition can be produced by a known method. For example, each component is mixed simultaneously or sequentially into a mixer such as a Henschel mixer, a V-type blender, a tumbler mixer, or a ribbon blender and mixed, and a multi-screw extruder such as a single-screw extruder or a twin-screw extruder. Alternatively, the flame retardant resin composition can be obtained by melt-kneading with a kneader, a Banbury mixer or the like.

  In particular, when a device excellent in kneading performance such as a multi-screw extruder, a kneader, or a Banbury mixer is used, a high-quality flame-retardant resin composition in which each component is more uniformly dispersed can be obtained. Moreover, an additive (for example, antioxidant) can also be added in the arbitrary steps as needed.

  The order in which each component is blended is not particularly limited. In particular, a copolymer of ethylene and vinyl ester (A), a propylene copolymer (B), a polypropylene (C), and optionally an ethylene / α-olefin copolymer (F) are melt-kneaded, It is preferable to melt-knead this with other components. Also, a part of these polymer components, the metal hydroxide (D) and the expanded graphite (E) are melt-kneaded to form a master batch, and then melt-kneaded. It is also preferable to do. In this case, a composition with a better balance of mechanical strength, flexibility, and flame retardancy can be obtained.

[Molded body]
The molded product of the present invention comprises the flame retardant resin composition described above. The shape of the molded body is not particularly limited, and can be molded into various shapes by melt molding. Examples of the melt molding method include extrusion molding, rotational molding, calendar molding, injection molding, compression molding, transfer molding, powder molding, blow molding, and vacuum molding. This molded body may be a composite with another material, for example, a laminate.

The molded body may include a high proportion of inorganic fillers, mechanical strength, so excellent as to balance the flexibility and flame retardancy, for example, widely wires, building materials for flame retardant sheet, for applications such as electronic equipment parts Available. More specifically, for example, it is suitable for wire coating applications such as a wire insulator and a wire sheath. In particular, the scratch resistance of a molded body such as an electric wire having a cylindrical shape can be improved. A coating layer such as an electric wire insulator or electric wire sheath can be formed around the electric wire by a known method such as extrusion molding.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these.

<Ingredients (A) to (G)>
Each component used in the examples is as follows.

[Copolymer of ethylene and vinyl ester (A)]
Ethylene-vinyl acetate copolymer (trade name EVAFLEX EV270, manufactured by Mitsui DuPont Polychemical Co., Ltd.) (hereinafter abbreviated as “EVA”)
[Propylene copolymer (B)]
[Propylene / ethylene / 1-butene copolymer (B-1)]
Propylene / ethylene / 1-butene random copolymer (MFR = 8.5 g / 10 min, Tm = not observed, ethylene content = 14 mol%, 1-butene content = 20 mol%, Mw / Mn = 2.0, Shore A hardness = 38, crystallinity (WAXD method) = 5% or less, mm value = 90%) (manufactured by the method described in JP-A No. 2007-186665) (hereinafter abbreviated as “PBER”)
[Propylene / 1-butene copolymer (B-2)]
A propylene / 1-butene copolymer (MFR = 7 g / 10 min, Tm = 75 ° C., 1-butene content 26 mol%, Mw / Mn = 2.1, crystallinity (WAXD method) = 28%) was used. . (Manufactured by the method described in JP-A No. 2007-186665) (hereinafter abbreviated as “PBR”)
[Polypropylene (C)]
Isotactic homopolypropylene (Tm = 160 ° C., MFR (230 ° C.) = 0.5 g / 10 min) (hereinafter abbreviated as “hPP”)
[Metal hydroxide (D)]
Magnesium hydroxide (trade name Magnifin (registered trademark) H5IV, manufactured by Albemarle) (hereinafter abbreviated as “MDH”)
[Expanded graphite (E)]
Expanded graphite (trade name Moehen Z (registered trademark) MZ-285, manufactured by Air Water Co., Ltd.)
[Ethylene / α-olefin copolymer (F)]
Ethylene / 1-butene copolymer produced using a metallocene catalyst (density = 885 kg / m ³ , MFR (g / 10 min) 190 ° C., under 2.16 kg load) = 0.5, Mw / Mn = 2.1 , B value = 1.05) (hereinafter abbreviated as “EBR”)
[Polymer composition (G)]
Laboplast mill (Toyo Seiki Co., Ltd.) was prepared by blending 80% by mass of the above-mentioned copolymer of ethylene and vinyl ester (A) and 20% by mass of the above-mentioned propylene / ethylene / 1-butene copolymer (B-1). And a polymer composition produced by kneading at 190 ° C.

<Measuring method of physical properties of each component>
The physical property values of the above components were measured as follows.
(1) Comonomer (ethylene, 1-butene) content:
^It was determined by analysis of ¹³ C-NMR spectrum.
(2) Melt flow rate (MFR):
Based on ASTM D-1238, the measurement was performed at 190 ° C. or 230 ° C. under a 2.16 kg load.
(3) Melting point (Tm):
An exothermic / endothermic curve of DSC was determined, and the temperature at the apex of the melting peak where ΔH during temperature increase was 1 J / g or more was defined as Tm. For measurement, the sample is packed in an aluminum pan, heated to 200 ° C. at 100 ° C./min, held at 200 ° C. for 5 minutes, lowered to −150 ° C. at 10 ° C./min, and then 200 ° C. at 10 ° C./min. It was obtained from the exothermic / endothermic curve when the temperature was raised to.
(4) Molecular weight distribution (Mw / Mn):
It measured at 140 degreeC by the ortho dichlorobenzene solvent by GPC (gel permeation chromatography).
(5) Density:
Measured according to ASTM D1505.
(6) Crystallinity:
RINT2500 (manufactured by Rigaku Corporation) was used as a measurement apparatus, and the measurement was performed by analysis of a wide-angle X-ray profile measured using CuKα as an X-ray source.
(7) Shore A hardness:
Sheets were produced with a press molding machine and measured according to ASTM D2240.

<Evaluation items of Examples and Comparative Examples>
(1) Tensile strength, 5% tensile modulus:
Based on JIS K7113-1, it was measured with a 2 mmt press sheet.
(2) Shore D hardness:
Measured according to ASTM D2240.
(3) Flame retardancy (combustion test):
Based on the combustion test established in UL standards UL94 V-0, V-1, and V-2, the test sample was punched out from the produced press sheet sample. This test is hereinafter abbreviated as “UL94”.

[Example 1]
The composition having the composition shown in Table 1 was kneaded using a lab plast mill (manufactured by Toyo Seiki Co., Ltd.). This was formed into a sheet having a thickness of 2 mm by a press molding machine (heating temperature 190 ° C., heating time 7 minutes, cooling condition 15 ° C./4 min, cooling rate about 40 ° C./min). The results of evaluating this sheet are shown in Table 1.

[Examples 2 to 5, Comparative Examples 1 to 4]
Evaluation was performed in the same manner as in Example 1 except that the composition was changed to the composition shown in Table 1. In addition, those not ranked in any of V-0, V-1, and V-2 were marked as no rank. The results are shown in Table 1.

  As shown in Table 1, the flame retardant resin composition of each example has better flame retardancy than the flame retardant resin composition of each comparative example, and the Shore D is 60 or less in all cases. The balance with flexibility was also excellent.

<Example 7>
Evaluation was performed in the same manner as in Example 1 except that the composition was changed to the composition shown in Table 2. The results are shown in Table 2.

As shown in Table 2, the flexibility was further improved by using a melt-kneaded product (polymer composition (G) ).

Claims (10)

As a polymer component,
Copolymer of ethylene and vinyl ester (A) 50 to 95% by mass,
5 to 50% by mass of a propylene-based copolymer (B) having an α-olefin content other than propylene of 10 to 60 mol%, and
Polypropylene (C) having a content of α-olefin other than propylene of less than 10 mol%, 0 to 40% by mass
[Total 100% by mass of components (A), (B) and (C)]
Containing
Furthermore, for a total of 100 parts by mass of the components (A), (B) and (C),
100 to 150 parts by mass of metal hydroxide (D), and
Containing 20 to 40 parts by mass of expanded graphite (E),
A flame-retardant resin composition in which the total amount of components (D) and (E) is 140 parts by mass or more with respect to 100 parts by mass in total of components (A), (B), and (C) . The propylene-based copolymer (B) is a random copolymer (B-1) of propylene / ethylene / α-olefin having 4 to 20 carbon atoms that satisfies the following conditions (m) and (n). Flame retardant resin composition.
(M) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 1-3.
(N) 40 to 85 mol% of propylene-derived structural units, 5 to 30 mol% of structural units derived from ethylene, and 5 to 30 mol% of structural units derived from α-olefins having 4 to 20 carbon atoms (here The total of the structural unit derived from propylene, the structural unit derived from ethylene, and the structural unit derived from α-olefin having 4 to 20 carbon atoms is 100 mol%. The difficulty according to claim 1, wherein the propylene-based copolymer (B) is a random copolymer (B-2) of propylene and an α-olefin having 4 to 20 carbon atoms that satisfies the following conditions (a) and (b). A flammable resin composition.
(A) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 1-3.
(B) the melting point Tm (° C.) and the comonomer constituent unit content M (mol%) determined by ¹³ C-NMR spectrum measurement,
146 exp (−0.022 M) ≧ Tm ≧ 125 exp (−0.032 M)
(Where Tm is less than 120 ° C.).   4. The composition according to claim 1, further comprising 0.1 to 30 parts by mass of an ethylene / α-olefin copolymer (F) with respect to 100 parts by mass in total of components (A), (B) and (C). The flame-retardant resin composition according to one item. A method for producing the flame retardant resin composition according to any one of claims 1 to 4,
A step of producing a polymer composition (G) by melt-kneading a polymer component containing at least a copolymer of ethylene and vinyl ester (A) and a propylene-based copolymer (B);
A method for producing a flame retardant resin composition comprising a step of melt-kneading at least a polymer composition (G), a metal hydroxide (D), and expanded graphite ( E ).   A flame retardant resin composition produced by the method according to claim 5.   The molded object which consists of a flame-retardant resin composition as described in any one of Claims 1-4 and 6.   The molded body according to claim 7, which is a wire insulator, a wire sheath, a flame retardant sheet for building materials, or an electronic device component.   The electric wire which has the insulator and / or electric wire sheath which are the molded objects of Claim 8.   The electric wire according to claim 9, wherein the electric wire is a power cord electric wire, an equipment electric wire, or an electric wire for indoor wiring.