JP2018154697A - Flame-retardant polyolefin resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retardant polyolefin resin composition excellent in flexibility, flame retardancy, and heat resistance and also excellent in productivity and oil resistance under high temperature.SOLUTION: The flame-retardant polyolefin resin composition is obtained by dynamically crosslinking a mixture containing the following components (A)-(E): (A) an olefinic polymer containing a propylene-ethylene block copolymer having a melting completion temperature of 166-175°C; (B) a thermoplastic resin containing an ethylene-α-olefin copolymer; (C) a paraffinic rubber softener; (D) a crosslinking agent; and (E) a flame retardant.SELECTED DRAWING: None

Description

  The present invention relates to a flame retardant polyolefin resin composition. Specifically, the present invention relates to a flame retardant polyolefin-based resin composition having excellent heat resistance, flexibility, flame retardancy, and productivity and excellent oil resistance. The flame-retardant polyolefin resin composition of the present invention is excellent in heat resistance, flexibility, flame retardancy, productivity, and oil resistance, and is suitable as a wire coating material.

  Polyvinyl chloride resin composition has excellent electrical insulation and self-extinguishing flame retardancy, so it has been widely used for wire coating, tubes, tapes, building materials, automotive parts, home appliance parts, etc. Yes. However, since the polyvinyl chloride resin composition contains chlorine, hydrogen chloride gas, which is a corrosive gas, is generated during combustion, and toxic gases such as dioxins may be generated depending on the combustion conditions. For this reason, as part of countermeasures against recent environmental problems, materials that do not contain halogens (hereinafter referred to as “non-halogen”) that do not contain halogens, and that do not have the possibility of generation of these toxic gases during combustion. .) Is used.

  Non-halogen materials include polyolefin resins and styrene resins typified by polypropylene and polyethylene. However, since polyolefin resins and the like are not flame retardant, they need to be flame retardant depending on the application. As a countermeasure, a method of adding a halogen-based flame retardant has been performed for a long time. However, since halogen-based flame retardants can also generate toxic gases during combustion, recently, as a non-halogen-based flame retardant, a method of incorporating a metal hydroxide such as magnesium hydroxide or aluminum hydroxide has been adopted. Yes.

  However, the flame retardant resin composition containing magnesium hydroxide, aluminum hydroxide, or the like can prevent the generation of halogen-based gas during combustion, but the required flame retardant performance, for example, UL-94 test V-0. In order to obtain the level, it is necessary to fill a large amount of a flame retardant, and there are problems such as inferior physical properties of the resin composition and inferior molding processing properties.

  Many proposals have been made in which a small amount of a halogen-based flame retardant is used to impart physical properties, molding processing properties, and flame retardancy to a resin composition (for example, Patent Documents 1 to 8).

JP 2001-220470 A JP 2001-226539 A JP 2000-248132 A JP-A-5-303918 JP 2011-243446 A JP 2009-43601 A JP 2001-279052 A JP-A-60-170612

There is a strong demand for the application of flame-retardant polyolefin materials in high-temperature environments such as engine rooms, and there is a strong demand for improving heat resistance in wire coating applications for automobile parts.
According to the knowledge of the present inventors, for example, the resin compositions of Patent Documents 2 and 7 are insufficient in heat resistance at a high temperature of 150 ° C. or more, and the conventional techniques have flame retardancy and heat resistance. The present situation is that no flame retardant resin composition having excellent properties, flexibility, and productivity and oil resistance is provided.

  The present invention has been made in view of the above circumstances, and its purpose is excellent in heat resistance, flexibility and flame retardancy, and in addition, oil resistance, in particular, flame resistance excellent in oil resistance and productivity at high temperatures. It is in providing a conductive polyolefin resin composition. Another object of the present invention is to provide a flame retardant polyolefin-based resin composition that is excellent in heat resistance, flexibility, flame retardancy, productivity, and oil resistance and is suitable as a wire coating material.

  As a result of intensive studies in view of the above problems, the inventor has moved an olefin polymer containing a specific propylene-ethylene block copolymer, a thermoplastic resin, a softening agent for paraffin rubber, a crosslinking agent, and a flame retardant. It has been found that a polyolefin-based resin composition obtained by mechanical crosslinking is excellent in heat resistance, flexibility and flame retardancy, and also excellent in oil resistance and productivity at high temperatures. The present invention has been accomplished based on these findings, and the gist thereof is as follows.

[1] A flame-retardant polyolefin resin composition obtained by dynamically crosslinking a mixture containing the following components (A) to (E).
Component (A): Olefin-based polymer component (B) containing a propylene-ethylene block copolymer having a melting end temperature of 166 to 175 ° C .: Thermoplastic resin component (C) containing an ethylene-α-olefin copolymer: Paraffinic rubber softener component (D): Crosslinker component (E): Flame retardant

[2] Flame retardancy according to [1], wherein the propylene-ethylene block copolymer in component (A) has an MFR (230 ° C., 21.2 N load) of 0.05 to 2.0 g / 10 min. Polyolefin resin composition.

[3] The flame retardant polyolefin resin composition according to [1] or [2], wherein the component (A) includes a propylene random copolymer.

[4] The flame-retardant polyolefin system according to any one of [1] to [3], wherein the propylene-ethylene block copolymer in component (A) has an ethylene content in the rubber of 72 to 90% by mass. Resin composition.

[5] The flame retardancy according to any one of [1] to [4], wherein the component (B) contains an ethylene-α-olefin-nonconjugated diene copolymer having an ethylene unit content of 50 to 75% by mass. Polyolefin resin composition.

[6] The flame retardant polyolefin resin composition according to [5], wherein the component (B) includes the following component (B3).
Component (B3): a block copolymer having at least two polymer blocks P derived from a vinyl aromatic compound and at least one polymer block Q derived from a conjugated diene and / or isobutylene, and the block At least one block copolymer selected from the group consisting of block copolymers obtained by hydrogenating the copolymer

[7] The flame retardant polyolefin according to any one of [1] to [6], wherein the ratio of component (B) to 100 parts by mass of component (A) and component (B) is 40 to 80 parts by mass. -Based resin composition.

[8] The flame-retardant polyolefin resin composition according to any one of [1] to [7], wherein the component (D) contains an organic peroxide and a crosslinking aid.

[9] The component (E) is a brominated flame retardant and / or an antimony flame retardant, and the ratio of the component (E) to the total 100 parts by mass of the component (A) and the component (B) is 30 to 80 parts by mass. The flame retardant polyolefin resin composition according to any one of [1] to [3].

[10] A molded product obtained by molding the flame-retardant polyolefin resin composition according to any one of [1] to [9].

[11] The molded article according to [10], which is a wire covering material.

  INDUSTRIAL APPLICABILITY According to the present invention, a flame-retardant polyolefin resin composition that is excellent in heat resistance, flexibility, and flame retardancy, and also excellent in oil resistance and productivity at high temperatures, and a wire coating material using the resin composition Is provided.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following description, and can be arbitrarily modified and implemented without departing from the gist of the present invention. In addition, in this specification, when expressing by putting a numerical value or a physical-property value before and behind using "-", it shall use as what includes the value before and behind.

[Flame Retardant Polyolefin Resin Composition]
The flame-retardant polyolefin resin composition of the present invention is obtained by dynamically crosslinking a mixture containing the following components (A) to (E) (hereinafter sometimes referred to as “mixture of the present invention”).
Component (A): Olefin-based polymer component (B) containing a propylene-ethylene block copolymer having a melting end temperature of 166 to 175 ° C .: Thermoplastic resin component (C) containing an ethylene-α-olefin copolymer: Paraffinic rubber softener component (D): Crosslinker component (E): Flame retardant

The flame-retardant polyolefin resin composition of the present invention is excellent in heat resistance, flexibility, and flame retardancy, and also has the effect of being excellent in oil resistance and productivity at high temperatures. It is presumed that heat resistance is improved when the flame-retardant polyolefin resin composition of the present invention is made of an olefin polymer containing a specific propylene-ethylene block copolymer. Further, when a specific thermoplastic resin is used, as a result, the ratio of aromatics contained in the polyolefin resin composition increases, so that the oil resistance performance to aromatic hydrocarbon-incompatible hydrocarbon oil is improved.

[Component (A)]
Component (A) is an olefin polymer containing a propylene-ethylene block copolymer having a melting end temperature of 166 to 175 ° C.

The melting end temperature of the propylene-ethylene block copolymer and the later-described propylene random copolymer contained in the component (A) can be measured by the following method according to JIS K7121. That is, the following steps (1) to (3) were sequentially performed using a differential scanning calorimeter (DSC 6220 manufactured by SSI Nanotechnology Co., Ltd.) to melt the propylene random copolymer and the propylene-ethylene block copolymer. Measure. In each step, time is plotted on the horizontal axis, and the heat of fusion is plotted on the vertical axis to obtain a melting curve, and the extrapolated peak end point (° C.) of the peak observed in step (3) is calculated as the melting point end temperature. .
Step (1): A sample of 5 mg is heated from room temperature at a rate of 100 ° C./min from 40 ° C. to 200 ° C., and held for 3 minutes after the temperature increase is completed.
Step (2): The temperature is decreased from 200 ° C. to 40 ° C. at a rate of 10 ° C./min, and is maintained for 3 minutes after the temperature decrease.
Step (3): The temperature is raised from 40 ° C. to 200 ° C. at a rate of 10 ° C./min.

  When the melting end temperature of the propylene-ethylene block copolymer contained in the component (A) is 166 ° C., heat resistance is imparted. From this point of view, the melting end temperature of this propylene-ethylene block copolymer is 166 ° C. or higher, preferably 170 ° C. or higher, while the upper limit is not particularly limited, but is usually 175 ° C. or lower.

  In the propylene-ethylene block copolymer contained in the component (A), the ethylene content in the rubber is measured by the method described in the examples below, and is preferably 72 to 90% by mass, more preferably. It is 75-85 mass%, More preferably, it is 80-85 mass%. It is preferable for the ethylene content in the rubber to be in the above-mentioned range since the 140 ° C. soluble component tends to increase and the heat resistance is excellent.

  The propylene-ethylene block copolymer contained in the component (A) also has a value of 140 ° C. soluble content (this value is an index of heat resistance) measured by a method described later of 50% by mass or more. It is preferable. Here, if it is a propylene-ethylene block copolymer whose 140 degreeC soluble content is 50 mass% or more, there are few parts soluble at high temperature, and it is excellent in heat resistance. From this viewpoint, the 140 ° C. soluble content of the propylene-ethylene block copolymer is more preferably 55% by mass or more, and further preferably 60% by mass or more. On the other hand, the upper limit of 140 ° C. soluble content is usually 95% by mass or less from the viewpoint of moldability.

  The propylene-ethylene block copolymer contained in the component (A) preferably satisfies at least one of the above-mentioned suitable ethylene content in rubber and 140 ° C. soluble component, and more preferably satisfies both.

  It is preferable that the melt flow rate (MFR) of the propylene-ethylene block copolymer contained in the component (A) is 0.05 to 2.6 g / 10 minutes. When the MFR of the propylene-ethylene block copolymer is 0.05 g / 10 min or more, the moldability is good, and when it is 2.6 g / 10 min or less, the dispersibility during melt-kneading is good. It becomes. From these viewpoints, the MFR of the propylene-ethylene block copolymer is more preferably 0.10 g / 10 min or more, still more preferably 0.50 g / 10 min or more, while more preferably 2.6 g. / 10 minutes or less, more preferably 2.0 g / 10 minutes or less.

  In addition, the melt flow rate (230 degreeC, 21.2N) of the propylene-ethylene block copolymer contained in a component (A) and the below-mentioned propylene random copolymer is measurement temperature 230 degreeC according to JISK7210 (1999). The measurement load is 21.2N.

  The olefin polymer of component (A) preferably further contains a propylene random copolymer in addition to the propylene-ethylene block copolymer.

  The propylene random copolymer is a copolymer having a propylene unit and a structural unit other than propylene. Specific examples of constituent units other than propylene include ethylene units and α-olefin units other than propylene units. Examples of constituent units other than the propylene units that may be contained in the propylene random copolymer include, for example, ethylene units, 1-butene units, 1-pentene units, 1-hexene units, 1-heptene units, and 1-octene units. 1-nonene unit, 1-decene unit, 1-undecene unit, 1-dodecene unit, 1-tridecene unit, 1-tetradecene unit, 1-pentadecene unit, 1-hexadecene unit, 1-heptadecene unit, 1-octadecene unit 1-nonadecene unit, 1-eicocene unit, 3-methyl-1-butene unit, 3-methyl-1-pentene unit, 4-methyl-1-pentene unit, 2-ethyl-1-hexene unit, 2,2 , 4-trimethyl-1-pentene unit and the like, preferably ethylene unit and 1-butene unit. A propylene random copolymer may contain only 1 type of these, or may contain 2 or more types.

  In the propylene random copolymer, the content of propylene units is preferably 90 to 99% by mass, more preferably 93 to 98% by mass. It is preferable from a viewpoint of a moldability that content of the propylene unit of a propylene random copolymer is the said range.

  The propylene random copolymer preferably has a melt flow rate (MFR) of 0.05 to 100 g / 10 min. When the MFR of the propylene random copolymer is 0.05 g / 10 min or more, the dispersibility during melt-kneading is improved, and when it is 100 g / 10 min or less, the mechanical properties are improved. From these viewpoints, the MFR of the propylene random copolymer is more preferably 0.05 g / 10 min or more, further preferably 0.5 g / 10 min or more, while more preferably 100 g / 10 min or less. More preferably, it is 50 g / 10 min or less.

  In addition, the melting end temperature of the propylene random copolymer is preferably 105 ° C. or higher, more preferably 115 ° C. or higher, and further preferably 125 ° C. or higher. On the other hand, the melting end temperature of the propylene random copolymer is preferably 150 ° C. or lower, and more preferably 140 ° C. or lower. When the melting end temperature of the propylene random copolymer is not less than the above lower limit value, it is preferable from the viewpoint of heat resistance, and when it is not more than the above upper limit value, unmelted spots are hardly generated, and it is preferable from the viewpoint of moldability.

  As a method for producing the propylene-ethylene block copolymer and the propylene random copolymer contained in the component (A), a known polymerization method using a known olefin polymerization catalyst is used. For example, a polymerization method using a Ziegler-Natta catalyst can be mentioned. As the polymerization method, a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like can be used, and two or more of these may be combined.

  The propylene-ethylene block copolymer and the propylene random copolymer can also be obtained as commercial products. Examples of such commercial products include Prime Polymer's Prime Polypro (registered trademark), Sumitomo Chemical's Sumitomo Noblen (registered trademark), Sun Allomer's polypropylene block copolymer, Nippon Polypro's Novatec (registered trademark) PP, LyondellBasel. Moplen (R), ExxonMobil's ExxonMobil PP, Formosa Plastics's Formolene (R), Borealis's Borealis PP, LG Chemical's SEETEC PP, A.M. Schulman's ASI POLYPROPYLENE, INEOS Olefins & Polymers, Inc. of INEOS PP, Braskem's Braskem PP, SAMSUNG TOTAL PETROCHEMICALS's Sumsung Total, Sabic's Sabic (registered trademark) PP, TOTAL PETROCHEMICALS company of TOTAL PETROCHEMICALS Polypropylene, SK Corporation of YUPLENE ( Registered trademark) and the like, which can be appropriately selected from these and used in combination.

  In the present invention, the content of the propylene-ethylene block copolymer in the component (A) is preferably 40% by mass or more, more preferably 50% by mass or more, and 60% by mass or more. Further preferred. On the other hand, the content of the propylene-ethylene block copolymer is preferably 90% by mass or less, preferably 80% by mass or less, and preferably 70% by mass or less. When the content of the propylene-ethylene block copolymer in the component (A) is not less than the above lower limit, it is excellent in heat resistance, and if it is not more than the above upper limit, unmelted spots are hardly produced, which is preferable from the viewpoint of moldability.

  In the present invention, when the component (A) contains a propylene random copolymer, the content is preferably 10% by mass or more, more preferably 15% by mass or more, and 20% by mass or more. Is more preferable. On the other hand, the content of the propylene random copolymer is preferably 60% by mass or less, preferably 50% by mass or less, and preferably 40% by mass or less. From the viewpoint of moldability, the content of the propylene random copolymer in the component (A) is at least the above lower limit, and the heat resistance is at most the above upper limit.

  In this case, the mass ratio of the propylene-ethylene block copolymer to the propylene random copolymer in the component (A) ([mass of propylene-ethylene block copolymer]: [mass of propylene random copolymer] ]) Is preferably 90:10 to 40:60 from the viewpoint of achieving both moldability and heat resistance, and from this viewpoint, it is more preferably 80:20 to 50:50.

  The propylene-ethylene block copolymer and the propylene random copolymer may be used alone or in combination of two or more types having different compositions and physical properties.

  Further, the component (A) may contain an olefin polymer other than the propylene-ethylene block copolymer and the propylene random copolymer as long as the effects of the present invention are not impaired, and the component (A) may contain. Examples of the other olefin-based polymer include one or more propylene homopolymers.

[Component (B)]
The component (B) used in the flame-retardant polyolefin resin composition of the present invention is a thermoplastic resin containing an ethylene-α-olefin copolymer (excluding those corresponding to the component (A)), The component (B) may further contain the following component (B3).
Component (B3): a block copolymer having at least two polymer blocks P derived from a vinyl aromatic compound and at least one polymer block Q derived from a conjugated diene and / or isobutylene, and the block At least one block copolymer in the group consisting of block copolymers formed by hydrogenating the copolymer Component (B) is a component that imparts flexibility to the flame retardant polyolefin resin composition of the present invention. is there.

The ethylene-α-olefin copolymer contained in the component (B) is not particularly limited as long as it is a copolymer containing at least an ethylene unit and an α-olefin unit. Specifically, the following component (B1), component (B2). Either component (B1) or component (B2) may be used alone or in combination, but the component (B) preferably contains at least component (B1).
Component (B1): Ethylene-α-olefin-nonconjugated diene copolymer Component (B2): Ethylene-α-olefin copolymer

  The α-olefin unit contained in the component (B1) includes 1-propylene unit, 1-butene unit, 2-methylpropylene unit, 1-pentene unit, 3-methyl-1-butene unit, 1-hexene unit, 4 -Methyl-1-pentene unit, 1-octene unit and the like can be exemplified. The α-olefin unit used in component (B1) is preferably the number of carbon atoms having a carbon-carbon double bond at the terminal carbon atom such as 1-propylene unit, 1-butene unit, 1-hexene unit, 1-octene unit, etc. 3 to 8 α-olefin units. Only one type of α-olefin in the component (B1) may be copolymerized with ethylene, or two or more types may be copolymerized with ethylene.

  As monomer units (non-conjugated diene units) based on the non-conjugated diene contained in the component (B1), 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl Chain unconjugated dienes such as 1,5-heptadiene, 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, And cyclic non-conjugated dienes such as 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene and 6-chloromethyl-5-isopropenyl-2-norbornene. Among these, 5-ethylidene-2-norbornene and dicyclopentadiene are preferable.

  The content of the ethylene unit in the component (B1) is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably based on the total amount of monomer units constituting the component (B1). Is 60% by mass or more, on the other hand, preferably 75% by mass or less, more preferably 70% by mass or less. It is preferable that the content of the ethylene unit is in the above range because moderate flexibility is provided.

  In the component (B1), the content of the α-olefin unit is preferably 20% by mass or more, more preferably 25% by mass or more, based on the total amount of monomer units constituting the component (B1). On the other hand, it is preferably 40% by mass or less, and more preferably 35% by mass or less. It is preferable that the content of the α-olefin unit is in the above range in order to provide appropriate flexibility.

  In the component (B1), the content of non-conjugated diene units is preferably 1% by mass or more, preferably 2% by mass or more, based on the total amount of monomer units constituting the component (B1). On the other hand, it is preferably 10% by mass or less, and preferably 7% by mass or less. The content of the non-conjugated diene unit is preferably not less than the above lower limit value from the viewpoint of increasing the degree of crosslinking of the flame retardant polyolefin resin composition, and is preferably not more than the above upper limit value from the viewpoint of moldability.

  In addition, content of each structural unit of a component (B1) can be calculated | required by infrared spectroscopy.

The Mooney viscosity (ML _{1 + 4} , 125 ° C.) of the component (B1) is usually from 30 to 120, preferably from 40 to 100. The Mooney viscosity (ML _{1 + 4} , 125 ° C.) of the component (B1) is preferably in the above range from the viewpoint of moldability.

The component (B1) preferably has a density of 0.850 g / cm ³ or more, more preferably 0.860 g / cm ³ or more, and preferably 0.900 g / cm ³ or less. 0.890 g / cm ³ or less is more preferable. The density of the component (B1) is preferably not less than the above lower limit value from the viewpoint of workability, and is preferably not more than the above upper limit value from the viewpoint of flexibility.

  As a manufacturing method of a component (B1), the well-known polymerization method using the well-known olefin polymerization catalyst is used. For example, a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method and the like using a complex catalyst such as a Ziegler-Natta catalyst, a metallocene complex, or a nonmetallocene complex may be used.

  A commercial item can also be used for a component (B1). For example, JSR EPR and EP57C manufactured by JSR, Mitsui EPT manufactured by Mitsui Chemicals, Espren (registered trademark) manufactured by Sumitomo Chemical Co., Keltan (registered trademark) manufactured by LANXESS, Nordel (registered trademark) manufactured by Dow, and Vistalon manufactured by ExxonMobil ( Applicable products can be selected from registered trademarks).

  The α-olefin unit that can be contained in the component (B2) includes 1-propylene unit, 1-butene unit, 2-methylpropylene unit, 1-pentene unit, 3-methyl-1-butene unit, 1-hexene. Examples thereof include a unit, 4-methyl-1-pentene unit, and 1-octene unit. The α-olefin unit used in component (B2) is preferably the number of carbon atoms having a carbon-carbon double bond at the terminal carbon atom such as 1-propylene unit, 1-butene unit, 1-hexene unit, 1-octene unit, etc. 3 to 8 α-olefin units. Only one type of α-olefin in the component (B2) may be copolymerized with ethylene, or two or more types may be copolymerized with ethylene.

  The content of the ethylene unit in the component (B2) is preferably 50% by mass or more and 55% by mass or more with respect to the total amount of the ethylene unit content and the α-olefin unit content. More preferably, it is more preferably 60% by mass or more, and on the other hand, it is preferably 80% by mass or less, and more preferably 75% by mass or less. The content of the ethylene unit of the component (B2) is preferably larger in the above range in order to prevent fusion due to blocking of the component (B2), and when the flame-retardant polyolefin resin composition of the present invention is molded. From the viewpoint of low-temperature impact resistance, it is preferable that the amount be less. In addition, content of each structural unit in a component (B2) can be calculated | required by infrared spectroscopy.

  Specific examples of the component (B2) include an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-1-octene copolymer, and an ethylene-propylene-1- Examples include butene copolymers, ethylene-propylene-1-hexene copolymers, and ethylene-propylene-1-octene copolymers. Among these, an ethylene-1-butene copolymer and an ethylene-1-octene copolymer are preferable.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the component (B2) is usually 20 to 120, preferably 30 to 100. The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the component (B2) is preferably in the above range from the viewpoint of moldability.

The component (B2) has a density of preferably 0.850 g / cm ³ or more, more preferably 0.860 g / cm ³ or more, and preferably 0.900 g / cm ³ or less. 0.890 g / cm ³ or less is more preferable. The density of the component (B2) is preferably not less than the above lower limit value from the viewpoint of workability, and is preferably not more than the above upper limit value from the viewpoint of flexibility.

  As a manufacturing method of a component (B2), the well-known polymerization method using the well-known olefin polymerization catalyst is used. For example, as an olefin polymerization catalyst, a Ziegler-Natta catalyst, a complex catalyst such as a metallocene complex or a nonmetallocene complex, and the like can be used. Examples thereof include a phase polymerization method. In addition, as the component (B2), a commercially available product can be used. Examples of the commercially available product include Engage (registered trademark) series manufactured by Dow Chemical Co., Ltd. and Tuffmer (registered trademark) series manufactured by Mitsui Chemicals.

In the component (B), when the component (B1) and the component (B2) are used in combination as an ethylene-α-olefin copolymer, their weight ratio ([weight of the component (B1)]: [component (B2)] The weight]) is preferably 1: 9 to 9: 1 from the viewpoint of reducing irregularities at the time of extrusion molding, and from this viewpoint, it is more preferably 3: 7 to 7: 3.
However, in this invention, it is preferable to use a component (B1) as an ethylene-alpha-olefin copolymer from a viewpoint of a moldability.
In addition, a component (B1) and a component (B2) may each use only 1 type, and may use it in combination of 2 or more types from which a composition and a physical property differ.

  Component (B3) used in the present invention is a block copolymer having at least two polymer blocks P derived from a vinyl aromatic compound and at least one polymer block Q derived from a conjugated diene and / or isobutylene. And at least one block copolymer in the group consisting of a block copolymer formed by hydrogenation of the block copolymer. The flame-retardant polyolefin-based resin composition of the present invention can obtain the effect of improving oil resistance and moldability at high temperatures by blending the component (B3).

  In the component (B3), the vinyl aromatic compound of the monomer constituting the block P is not particularly limited, but styrene derivatives such as styrene and α-methylstyrene are preferable. Of these, styrene is the main component. Here, “mainly” in the component (B3) means 50% by mass or more. The block P may contain a monomer other than the vinyl aromatic compound as a raw material.

  Examples of the monomer other than the vinyl aromatic compound include ethylene and α-olefin. Moreover, when the block P contains monomers other than the said vinyl aromatic compound as a raw material, the content is less than 50 mass%, Preferably it is 40 mass% or less. When the content of monomers other than the vinyl aromatic compound is within this range, the effect of improving oil resistance and moldability at high temperatures can be obtained.

  Although the conjugated diene of the monomer constituting the block Q is not particularly limited, butadiene and / or isoprene is preferable, and butadiene and isoprene are more preferable. The block Q may contain a monomer other than the conjugated diene as a raw material.

  Examples of the monomer other than the conjugated diene include isobutylene and styrene. Moreover, when the block Q contains monomers other than the said conjugated diene as a raw material, the content is less than 50 mass%, Preferably it is 40 mass% or less. When the content of monomers other than the conjugated diene is within this range, bleeding out tends to be suppressed.

Component (B3) block copolymer is a hydrogenated block copolymer obtained by hydrogenating a block copolymer having at least two polymer blocks P and at least one polymer block Q. It may be. More specifically, it may be a hydrogenated block copolymer obtained by hydrogenating double bonds of the block copolymer block Q. Although the hydrogenation rate of the block Q is not specifically limited, Preferably it is 80-100 mass%, More preferably, it is 90-100 mass%. By hydrogenating the block Q within the above range, the adhesive property of the resulting modified polyolefin composition tends to decrease and the elastic property tends to increase. The same applies to the case where the block P uses a diene component as a raw material. The hydrogenation rate can be measured by ¹³ C-NMR.

  When the conjugated diene monomer constituting the block Q is butadiene, the butadiene in the microstructure can take a 1,4-addition structure and a 1,2-addition structure. In particular, the block Q is hydrogenated. When it is a derivative and is mainly composed of butadiene, the 1,4-addition structure of butadiene in the microstructure of the block Q is preferably 10 to 100% by mass.

  When the conjugated diene of the monomer constituting the block Q is isoprene, the isoprene in the microstructure can take a 1,2-addition structure, a 1,4-addition structure, and a 3,4-addition structure. Similarly, in particular, when the block Q is a hydrogenated derivative and the block Q is composed of isoprene, the 1,4-addition structure of isoprene in the microstructure of the block Q is 60 to 100% by mass. Is preferred.

  Further, when the block Q is a hydrogenated derivative and the conjugated diene monomer constituting the block Q contains butadiene and isoprene, the 1,4-addition structure of butadiene and isoprene in the microstructure of the block Q is These are preferably 20 to 100% by mass and 60 to 100% by mass, respectively.

In any case, by setting the ratio of the 1,4-addition structure within the above range, the adhesive property of the resulting modified polyolefin composition tends to decrease and the elastic property tends to increase. The ratio of 1,4-addition structure (hereinafter sometimes referred to as “1,4-microstructure ratio”) can be measured by ¹³ C-NMR.

  The component (B3) in the present invention is not particularly limited as long as it has a structure having at least two polymer blocks P and at least one polymer block Q, and may be any of linear, branched, radial, etc. However, the block copolymer represented by the following formula (2) or (3) is preferable. Furthermore, the block copolymer represented by the following formula (2) or (3) is more preferably a hydrogenated block copolymer obtained by hydrogenation. When the copolymer represented by the following formula (2) or (3) is a hydrogenated block copolymer, the thermal stability is improved.

P- (Q-P) m (2)
(PQ) n (3)
(In the formula, P represents a polymer block P, Q represents a polymer block Q, m represents an integer of 1 to 5, and n represents an integer of 2 to 5.)

  In formula (2) or (3), m and n are preferably larger in terms of lowering the order-disorder transition temperature as a rubbery polymer, but smaller in terms of ease of production and cost. Good.

  When component (B3) is a hydrogenated block copolymer represented by formula (2) or (3) and block Q is composed of butadiene, 1,4-addition of butadiene in the microstructure of block Q The structure is preferably 20 to 100% by mass. Similarly, when the block Q is composed of isoprene, the 1,4-addition structure of isoprene in the microstructure of the block Q is preferably 60 to 100% by mass. Similarly, when the block Q is composed of butadiene and isoprene, the 1,4-addition structure of butadiene and isoprene in the microstructure of the block Q may be 20 to 100% by mass and 60 to 100% by mass, respectively. preferable. In any case, by setting the 1,4-microstructure ratio within the above range, the adhesive property of the resulting modified polyolefin composition tends to be lowered and the elastic property tends to be increased.

  The block copolymer and / or hydrogenated block copolymer (hereinafter sometimes referred to as “(hydrogenated) block copolymer”) is represented by the formula (3) because of its excellent rubber elasticity. The (hydrogenated) block copolymer represented by the formula (2) is more preferable than the (hydrogenated) block copolymer, and the (hydrogenated) block represented by the formula (2) in which m is 3 or less. A copolymer is more preferred, and a (hydrogenated) block copolymer represented by the formula (2) in which m is 2 or less is more preferred, and a formula (2) in which m is 1 (hydrogenated). A block copolymer is most preferred.

  Although the mass ratio of the block P and the block Q which comprise a component (B3) is arbitrary, there are many blocks P from the point of the mechanical strength of the flame-retardant polyolefin-type resin composition of this invention, and a heat-fusion strength. On the other hand, it is preferable that the number of blocks P is small in terms of flexibility, profile extrusion moldability, and suppression of bleed out.

  The mass ratio of the block P in the component (B3) is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 30% by mass or more, and preferably 60% by mass or less, more preferably It is 50 mass% or less, More preferably, it is 45 mass% or less.

  The method for producing the component (B3) in the present invention is not particularly limited as long as the above structure and physical properties can be obtained. Specifically, for example, it can be obtained by performing block polymerization in an inert solvent using a lithium catalyst or the like by the method described in Japanese Patent Publication No. 40-23798. The block copolymer may be hydrogenated (hydrogenated), for example, as described in JP-B-42-8704, JP-B-43-6636, JP-A-59-133203, and JP-A-60-79005. Can be carried out in an inert solvent in the presence of a hydrogenation catalyst. In this hydrogenation treatment, 50% or more of the olefinic double bonds in the polymer block are preferably hydrogenated, more preferably 80% or more are hydrogenated, and in the polymer block It is preferable that 25% or less of the aromatic unsaturated bond is hydrogenated.

  Component (B3) can be obtained as a commercial product. Examples of commercially available products include hydrogenated block copolymers such as “TAIPOL series” manufactured by TSRC, “KRATON (registered trademark) -G series” manufactured by Kraton Polymer, and “Septon (registered trademark)” manufactured by Kuraray. ) Series ”,“ Hybler (registered trademark) series ”,“ Tough Tech (registered trademark) series ”,“ Asaprene (registered trademark) series ”manufactured by Asahi Kasei Corporation, and the like. Commercially available non-hydrogenated block copolymers include “KRATON (registered trademark) -A series” manufactured by Kraton Polymer Co., Ltd., “Hiblur (registered trademark) series” manufactured by Kuraray Co., Ltd., “Tufrene ( Registered trademark) series ”and the like.

  As the component (B3), only one kind may be used, or two or more kinds having different block compositions and physical properties may be mixed and used.

  When a component (B) contains a component (B3), it is preferable that content of the component (B3) in 100 mass parts of components (B) is 10-30 mass parts, especially 15-25 mass parts. From the viewpoint of moldability, the ratio of the component (B3) is preferably not less than the above lower limit, and preferably not more than the above upper limit from the viewpoint of heat resistance.

[Content Ratio of Component (A) and Component (B)]
The mixture of the present invention contains 40 to 80 parts by mass, particularly 30 to 70 parts by mass, especially 20 to 60 parts by mass of the component (B) with respect to 100 parts by mass in total of the component (A) and the component (B). Is preferred. That is, from the viewpoint of moldability of the flame-retardant polyolefin resin composition of the present invention, the component (B) is preferably not less than the above lower limit, and preferably not more than the above upper limit from the viewpoint of moldability.

[Component (C)]
The mixture of the present invention contains the following component (C) from the viewpoint of improving moldability.
Component (C): Paraffinic rubber softener

  Commercially available hydrocarbon rubber softeners include mineral oil softeners and synthetic resin softeners, and mineral oil softeners are preferred from the viewpoint of affinity with other components. Mineral oil softeners are generally a mixture of aromatic hydrocarbons, naphthenic hydrocarbons and paraffinic hydrocarbons, with paraffinic oils in which 50% or more of all carbon atoms are paraffinic hydrocarbons, Those in which 30 to 45% of all carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of all carbon atoms are aromatic hydrocarbons are called aromatic oils. Among these, in the present invention, a paraffinic rubber softening agent which is a paraffinic oil is used. In addition, the paraffinic rubber softener may be used alone, or two or more may be used in any combination and ratio.

  The kinematic viscosity at 40 ° C. of the softener for paraffinic rubber of component (C) is not particularly limited, but is preferably 20 cSt or more, more preferably 50 cSt or more, and preferably 800 cSt or less, more preferably 600 cSt or less. . The flash point (COC method) of the hydrocarbon rubber softener is preferably 200 ° C. or higher, more preferably 250 ° C. or higher.

  The softening agent for paraffinic rubber of component (C) can be obtained as a commercial product. Examples of applicable commercial products include Nisshi Polybutene (registered trademark) HV series manufactured by JX Nippon Oil & Energy Corporation, and Diana (registered trademark) process oil PW series manufactured by Idemitsu Kosan Co., Ltd. Can be appropriately selected and used.

  The content of the component (C) in the mixture of the present invention is preferably 3 parts by mass or more, more preferably from the viewpoint of flexibility with respect to a total of 100 parts by mass of the component (A) and the component (B). Is 5 parts by mass or more, more preferably 10 parts by mass or more. Further, the content of the component (C) is preferably 50 parts by mass or less, more preferably 40 parts by mass, from the viewpoint of low temperature impact resistance, with respect to 100 parts by mass in total of the component (A) and the component (B). The amount is at most 30 parts by mass, more preferably at most 30 parts by mass.

[Component (D)]
The flame retardant polyolefin resin composition of the present invention is obtained by dynamic crosslinking in the presence of a crosslinking agent. By this dynamic crosslinking treatment, the flame-retardant polyolefin resin composition of the present invention has good heat resistance and moldability.

  The crosslinking agent of component (D) used for this dynamic crosslinking treatment comprises an organic peroxide and a crosslinking aid, and these organic peroxides and crosslinking aids may be used alone or in combination of two or more. Can also be used in combination.

  As the organic peroxide that can be used as the cross-linking agent, any of aromatic organic peroxides and aliphatic organic peroxides can be used. Specifically, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl -2,5-di (t-butylperoxy) hexyne-3, 1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy) -3,3,5 -Dialkyl peroxides such as trimethylcyclohexane; t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2 Peroxyesters such as, 5-di (benzoylperoxy) hexyne-3; acetyl peroxide, lauroyl peroxide, benzoy Peroxide, p- chlorobenzoyl peroxide, hydroperoxide, and the like, such as 2,4-dichlorobenzoyl peroxide and the like. Among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is preferable. These organic peroxides may be used alone or in combination of two or more.

Examples of the crosslinking aid include peroxides such as sulfur, p-quinonedioxime, p-dinitrosobenzene, and 1,3-diphenylguanidine; stannous chloride / anhydride, stannous chloride / Crosslinking aids for phenolic resins such as dihydrate and ferric chloride; polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate; ethylene glycol di (meth) acrylate, diethylene glycol di Examples thereof include polyfunctional (meth) acrylate compounds such as (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and allyl (meth) acrylate. These may be used alone or in combination of two or more.
Among these, it is particularly preferable that divinylbenzene is included from the viewpoint of good progress of the dynamic crosslinking reaction.

In the flame-retardant polyolefin resin composition of the present invention, the amount of the organic peroxide used as the component (D) is crosslinked with respect to a total of 100 parts by mass of the component (A), the component (B) and the component (C). From the viewpoint of sufficiently proceeding the reaction, it is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.3 parts by mass or more. On the other hand, the amount of the organic peroxide used is preferably 10 parts by mass or less from the viewpoint of controlling the crosslinking reaction with respect to 100 parts by mass in total of the component (A), the component (B) and the component (C). More preferably, it is 8 mass parts or less, More preferably, it is 6 mass parts or less, Most preferably, it is 4 mass parts or less.
Moreover, when using divinylbenzene as a crosslinking aid of a component (D), the usage-amount is 0.1-2 mass with respect to a total of 100 mass parts of a component (A), a component (B), and a component (C). Part, particularly 0.2 to 1 part by weight, is preferable from the viewpoint of moldability.

[Component (E)]
In the present invention, a flame retardant is used as the component (E) in order to obtain flame retardancy as a flame retardant polyolefin resin composition.
Although there is no restriction | limiting in particular as a flame retardant of a component (E), A bromine type flame retardant and / or an antimony type flame retardant are suitable.

  Examples of brominated flame retardants include aromatic bromine compounds, brominated epoxy resins, brominated polycarbonates, brominated aromatic vinyl copolymers, brominated cyanurate resins, brominated polyphenylene ethers, and more specifically, ethylene. Bis (pentabromobenzene), decabromodiphenyl oxide, ethylenebistetrabromophthalimide, poly (pentabromobenzyl acrylate), tetrabromobisphenol A, oligomers of tetrabromobisphenol A, brominated bisphenol epoxy resin, brominated bisphenol phenoxy Brominated polyphenylene oxides such as resins, brominated bisphenol-based polycarbonates, brominated polystyrene such as polydibromostyrene, brominated cross-linked polystyrene, polydibromophenylene oxide, etc. Id, decabromodiphenyl diphenyl oxide bisphenol condensate and halogenated phosphoric acid esters, and the like. The bromine content in the brominated flame retardant is preferably 60% by mass or more, and more preferably 80% by mass or more. As the brominated flame retardant having a bromine content of 80% by mass or more, ethylene bis (pentabromobenzene) is preferable.

  Examples of the antimony flame retardant include antimony trioxide, antimony pentoxide, and anhydrous sodium antimonate. Among them, antimony trioxide is preferable.

  Each of the antimony flame retardant and the antimony flame retardant may be used alone or in combination of two or more. One or two brominated flame retardants and one or more antimony flame retardants may be used in combination.

  The flame retardant of component (E) is preferably used in an amount of 30 to 80 parts by mass, more preferably 40 to 70 parts by mass with respect to 100 parts by mass in total of component (A) and component (B). If the flame retardant is less than the above lower limit, sufficient flame retardancy cannot be obtained, and if it exceeds the above upper limit, moldability tends to deteriorate.

[Other ingredients]
In the mixture of the present invention, in addition to the components (A) to (E), other components can be blended as necessary within a range not impairing the effects of the present invention.

  Examples of other components include resins such as thermoplastic resins and elastomers other than components (A) and (B), antioxidants, fillers, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizers, Lubricant, anti-fogging agent, anti-blocking agent, slip agent, dispersant, colorant, antistatic agent, conductivity-imparting agent, metal deactivator, molecular weight modifier, antibacterial agent, antifungal agent, fluorescent whitening agent And various other additives. Any of these may be used alone or in combination.

  Examples of thermoplastic resins other than components (A) and (B) include polyphenylene ether resins; polyamide resins such as nylon 6 and nylon 66; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyoxymethylene homo Examples thereof include polyoxymethylene resins such as polymers and polyoxymethylene copolymers; polymethyl methacrylate resins and polyolefin resins (excluding those corresponding to component (A) or component (B)). Examples of elastomers other than components (A) and (B) include styrene elastomers; polyester elastomers; polybutadiene and the like.

  Examples of the antioxidant include phenolic antioxidants, phosphite antioxidants, thioether antioxidants, and the like. When using antioxidant, it is normally used in 0.01-3.0 mass parts with respect to a total of 100 mass parts of a component (A), a component (B), and a component (C).

  Examples of the filler include glass fiber, hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, metal soap, titanium dioxide, and carbon black. When using a filler, it is normally used in 0.1-50 mass parts with respect to a total of 100 mass parts of a component (A), a component (B), and a component (C).

[Method for Producing Flame Retardant Polyolefin Resin Composition]
The flame-retardant polyolefin-based resin composition of the present invention is obtained by dynamically crosslinking the mixture of the present invention containing a predetermined amount of components (A) to (E) and other components used as necessary. Is.

  In the present invention, “dynamic crosslinking” means kneading in a molten or semi-molten state in the presence of a crosslinking agent as component (D). This dynamic cross-linking is preferably performed by melt kneading, and as a mixing and kneading apparatus therefor, for example, a non-open Banbury mixer, a mixing roll, a kneader, a twin screw extruder, or the like is used. Among these, it is preferable to use a twin screw extruder. As a preferable aspect of the manufacturing method using this twin-screw extruder, each component is supplied to the raw material supply port (hopper) of the twin-screw extruder which has a several raw material supply port, and dynamic crosslinking is performed.

  The temperature at the time of dynamic crosslinking is usually 80 to 300 ° C, preferably 100 to 250 ° C. Moreover, the time which performs dynamic heat processing is 0.1 to 30 minutes normally.

[Molded products / uses]
The flame-retardant polyolefin resin composition of the present invention is formed into a molded body by various molding methods such as injection molding, extrusion molding, hollow molding, and compression molding, which are usually used for polyolefin resin compositions. Of these, injection molding and extrusion molding are preferred. Moreover, it can also be set as the molded object which performed secondary processing, such as lamination molding and thermoforming, after performing these shaping | molding. In particular, the flame retardant polyolefin-based resin composition of the present invention is excellent in extrusion moldability and reduced in generation of eyes and scum when molded, and thus is suitable for extrusion molding, particularly profile extrusion molding. .

  The flame-retardant polyolefin resin composition of the present invention can be used in a wide range of fields such as electric wires; electric wire protective tubes; tubes; The thermoplastic elastomer composition of the present invention is particularly suitable as a wire coating material among those listed above.

  EXAMPLES Hereinafter, although the content of this invention is demonstrated more concretely using an Example, this invention is not limited by a following example, unless the summary is exceeded. The values of various production conditions and evaluation results in the following examples have meanings as preferred values of the upper limit or lower limit in the embodiment of the present invention, and preferred ranges are the upper limit or lower limit values described above, and It may be a range defined by a combination of values of the examples or values between the examples.

[material]
The raw materials used in the following examples and comparative examples are as follows.

[Component (A)]
A1:
Propylene random copolymer; specific gravity: 0.90 g / cm ³ , MFR (230 ° C., 21.2 N load): 0.8 g / 10 minutes, melting end temperature: 150 ° C., ethylene content in rubber: 0% by mass , Nippon Polypro Co., Ltd.
A2:
Propylene-ethylene block copolymer-1; specific gravity: 0.90 g / cm ³ , MFR (230 ° C., 21.2 N load): 1.5 g / 10 minutes, melting end temperature: 170 ° C., ethylene content in rubber : 80% by mass, 140 ° C. soluble content: 70% by mass, 100 ° C. soluble content: 30% by mass, Novatec PP (registered trademark) EC7 manufactured by Nippon Polypro Co., Ltd.
A3:
Propylene-ethylene block copolymer-2; specific gravity: 0.90 g / cm ³ , MFR (230 ° C., 21.2 N load): 0.5 g / 10 minutes, melting end temperature: 170 ° C., ethylene content in rubber : 83% by mass, 140 ° C. soluble content: 77% by mass, 100 ° C. soluble content: 23% by mass, Novatec PP (registered trademark) EC9 manufactured by Nippon Polypro Co., Ltd.
A4:
Propylene-ethylene block copolymer-3; specific gravity: 0.90 g / cm ³ , MFR (230 ° C., 21.2 N load): 2.7 g / 10 minutes, melting end temperature: 165 ° C., ethylene content in rubber : 91% by mass, soluble at 140 ° C: 73% by mass, soluble at 100 ° C: 27% by mass, Novatec PP (registered trademark) BC6 manufactured by Nippon Polypro Co., Ltd.

<Component (B)>
B1:
Ethylene-α-olefin-nonconjugated diene copolymer (EPDM-1); Mooney viscosity (ML _{1 + 4} , 125 ° C.): 61, ethylene unit content: 66 mass%, ethylidene norbornene unit content: 5.0 mass% ), EP3092PM manufactured by Mitsui Chemicals, Inc.
Ethylene-α-olefin-nonconjugated diene copolymer B2:
Ethylene-α-olefin-nonconjugated diene copolymer (EPDM-2); Mooney viscosity (ML _{1 + 4} , 125 ° C.): 64, ethylene unit content: 67% by mass, ethylidene norbornene unit content: 4.5% by mass ), EP505EC manufactured by JSR Corporation
B3:
Hydrogenated styrene-butadiene block copolymer (SEBS); specific gravity: 0.91 g / cm ³ , styrene unit content: 33 mass%, TAIPOL SEBS-6151 manufactured by TSRC

<Ingredient (C)>
C1:
Paraffinic rubber softener: Kinematic viscosity at 40 ° C .: 95.5 cSt, pour point: −15 ° C., flash point: 272 ° C.), Diana Process Oil PW90 manufactured by Idemitsu Kosan Co., Ltd.

<Crosslinking agent>
D1:
Cross-linking aid: mixture of 60% by weight of divinylbenzene and 40% by weight of ethylvinylbenzene, divinylbenzene D2 manufactured by Wako Pure Chemical Industries, Ltd .:
Organic peroxide; mixture of 40% by mass of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 60% by mass of calcium carbonate, Kayahexa AD40C manufactured by Kayaku Akzo Corporation

<Flame Retardant>
E1:
Brominated flame retardant; ethylenebis (pentabromobenzene) (bromine content 82 mass%), SAYTEX 8010 manufactured by Albemarle
E2:
Antimony flame retardant; antimony trioxide, manufactured by Nippon Seiko Co., Ltd. PATOX-KN

[Evaluation method]
The evaluation method of the flame-retardant polyolefin resin composition in the following examples and comparative examples is as follows.

<PP characteristics>
<Melting end temperature>
The melting end temperature was measured by the following method according to JIS K7121. That is, the following steps (1) to (3) were sequentially performed using a differential scanning calorimeter (DSC 6220 manufactured by SSI Nanotechnology Co., Ltd.), and a polypropylene resin (here, polypropylene resin is A1 in the table) ~ A4 component)) is measured. In each process, time is plotted on the horizontal axis and the heat of fusion is plotted on the vertical axis to obtain a melting curve, and the extrapolated peak end point (° C.) of the peak observed in step (3) is calculated as the melting point end point. .
Step (1): A sample of 5 mg is heated from room temperature at a rate of 100 ° C./min from 40 ° C. to 200 ° C., and held for 3 minutes after the temperature increase is completed.
Step (2): The temperature is decreased from 200 ° C. to 40 ° C. at a rate of 10 ° C./min, and is maintained for 3 minutes after the temperature decrease.
Step (3): The temperature is raised from 40 ° C. to 200 ° C. at a rate of 10 ° C./min.

<Ethylene content in rubber>
The measurement of the ethylene content in the rubber was performed as follows. Cross sorter as a measuring device (CFC made by Dia Instruments)
T101) was used. This cross fractionation apparatus includes a temperature rising elution fractionation (TREF) mechanism for fractionating a sample using a difference in dissolution temperature, and a size exclusion chromatograph (SEC) for further fractionating the classified sections by molecular size. Connected online.
First, a sample to be measured is dissolved at 140 ° C. using a solvent (o-dichlorobenzene) so as to be 3 mg / ml, and this is injected into a sample loop in the measuring apparatus. The following measurements are automatically performed according to the set conditions. The sample solution retained in the sample loop is separated into TREF columns (a stainless steel column attached to the apparatus with an inner diameter of 4 mm and a length of 150 mm filled with glass beads as an inert carrier) that is separated using the difference in dissolution temperature. Inject 0.4 ml. The sample is then cooled at a rate of 1 ° C./min from 140 ° C. to 0 ° C. and coated on the inert carrier. At this time, a polymer layer is formed on the surface of the inert carrier in the order of high crystal components (easy to crystallize) to low crystal components (hard to crystallize). After the TREF column is held at 0 ° C. for another 30 minutes, 2 ml of components dissolved at the temperature of 0 ° C. are injected from the TREF column to the SEC column (three Showa Denko AD806MS) at a flow rate of 1 ml / min. . While molecular size fractionation is performed by SEC, the temperature is raised to the next elution temperature (5 ° C.) in the TREF column, and held at that temperature for about 30 minutes. Measurement of each elution segment by SEC was performed at 39 minute intervals. The elution temperature is raised stepwise at a lower temperature.
0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120, 140 ° C
The solution fractionated by the molecular size in the SEC column was measured for absorbance proportional to the polymer concentration with an infrared spectrophotometer attached to the device (wavelength 3.42μ, detected by stretching vibration of methylene). A chromatogram is obtained. Using the built-in data processing software, the base line of the chromatogram of each elution temperature segment obtained by the above measurement is drawn and processed. The area of each chromatogram is integrated and an integrated elution curve is calculated. Also, the differential elution curve is calculated by differentiating the integral elution curve with temperature. The portion eluted so far was defined as the total rubber content. The elution part was concentrated, IR measurement was performed, and the ratio of ethylene and propylene was calculated.

<140 ° C soluble content>
The ratio of elution in the region of 100 to 140 ° C. was calculated as the 140 ° C. soluble component from the TREF integrated elution curve obtained above.

<100 ° C soluble content>
From the TREF integrated elution curve obtained above, the proportion eluted in the 0-100 ° C region was calculated as the 100 ° C soluble fraction.

<Oil resistance test>
A No. 3 dumbbell piece punched out from an extruded tape (thickness 1 mm) was immersed in oil adjusted to 60 ° C. (IRM902, manufactured by Sun Oil Co., Ltd.) for 168 hours. Then, the adhered oil was wiped off and kept in an environment of 23 ° C. and 50% RH for 24 hours.
The tensile strength and tensile elongation were measured according to C-3005. The tensile speed was 200 mm / min.
Using the value of a tensile test not immersed in oil as a reference (100%), the retention rate was calculated for each of tensile strength and tensile elongation, and the residual tensile strength and residual tensile elongation were obtained. It is preferable that both the tensile strength residual rate and the tensile elongation residual rate have a high value.

<Heating deformation rate>
Using a press sheet having a thickness of 2 mm, the heat deformation rate was measured in accordance with JIS K6723.
The test conditions were set temperature: 150 ° C., weight: 2 Kgf, weight time: 1 hour, and the rate of change of the press sheet thickness before the test and the thickness after the test was measured. A smaller thickness change rate is preferable.

<A hardness>
A 2 mm thick press sheet was stacked on three sheets, and the A hardness was measured in accordance with JIS K6253 (JIS-A).

<Flame retardance test>
A test piece (length: 127 mm, width: 12.7 mm, thickness: 3 mm) obtained from a 3 mm-thick press sheet was kept vertical, and the flame was removed after indirect flame was burned at the lower end for 10 seconds, The time for the fire that ignited the test piece to extinguish was measured. Next, at the same time that the fire was extinguished, the second flame contact was performed for 10 seconds, and the time when the ignited fire extinguished was measured in the same manner as the first time. Furthermore, it was evaluated whether or not the cotton installed under the test piece was ignited by the falling fire type.
From the results of the first and second burning times and the presence or absence of cotton ignition, the flammability was evaluated according to the UL-94V standard. The combustion performance is good in the order of V-0>V-1> V-2.

<Extruded tape appearance>
The appearance of the extruded tape was observed, the surface was smooth, and the following three levels were evaluated based on the number of bumps and the size of the bumps.
◎: Excellent ○: Good ×: Bad

[Examples 1 to 3, Comparative Examples 1 and 2]
Each component shown in Table-1 was inserted into a pressure kneader having an internal volume of 1.0 L at the ratio shown in Table-1, kneaded at a jacket kneader set temperature of 80-170 ° C, and the resin temperature due to self-heating due to shearing. When the temperature reached 190 ° C., the kneading was finished. This dynamic cross-linking treatment time is 20 minutes. The obtained kneaded product was further formed into a sheet with an open roll having a surface temperature of 140 ° C., and then pelletized with a pelletizer to prepare a resin composition.

After forming a sheet having a thickness of 2 to 3 mm with an open roll having a surface temperature of 140 ° C. using the obtained pellets, a sheet having a thickness of 2 mm or 3 mm is formed by press molding (temperature 190 ° C., pressure 10 MPa). Got. Table 1 shows the results of the heat deformation rate, the A hardness, and the flame retardancy test performed on the press sheet by the method described above.
Moreover, the obtained pellet was extrusion-molded at 200 degreeC using the 20-mm single-screw extruder, and the extrusion tape of width 50mm x thickness 1mm was obtained. Table 1 shows the results of the extrusion tape appearance, tensile test, and oil resistance test performed on the extruded tape by the methods described above.
The PP characteristics in Table 1 show the following values.

[Evaluation results]
As shown in Table 1, the heat deformation rate of Examples 1-3 is 8-19%, the heat deformation rate of Comparative Examples 1-2 is 20-100%, and Examples 1-3 are Comparative Example 1. Compared with ˜2, the heat deformation rate was low. In the “heating deformation rate” evaluation, it is understood that Examples 1 to 3 are excellent in heat resistance. Furthermore, Example 3 in which a part of the propylene-ethylene block copolymer in Example 2 was replaced with a propylene random copolymer was higher in the “oil resistance test” than in Example 2 in the residual tensile strength and residual tensile elongation. showed that. This shows that it is excellent in high temperature oil resistance. In addition, as a result of evaluation of “extruded tape appearance”, Example 3 has the smoothest surface, the fewest number of blisters, and the size of the flaws often seen compared with Examples 1-2 and Comparative Examples 1-2. It was also small. Therefore, the molded product obtained from Example 3 is likely to have a good appearance and is considered to be excellent in productivity.

  Moreover, in Comparative Example 1, the end-of-melting temperature of the propylene-ethylene block copolymer or the propylene random copolymer is lower than in Examples 1 to 3. In addition, the ethylene content in the rubber is low, and the content soluble at 100 ° C. is large. Therefore, it can be seen that the evaluation of “heating deformation rate” which is an index of heat resistance is inferior.

  The flame-retardant polyolefin resin composition of the present invention can be used in a wide range of fields such as electric wires; electric wire protective tubes; tubes; The flame retardant polyolefin-based resin composition of the present invention is particularly suitable as a wire covering material among those listed above.

Claims (11)

A flame retardant polyolefin resin composition obtained by dynamically crosslinking a mixture containing the following components (A) to (E).
Component (A): Olefin-based polymer component (B) containing a propylene-ethylene block copolymer having a melting end temperature of 166 to 175 ° C .: Thermoplastic resin component (C) containing an ethylene-α-olefin copolymer: Paraffinic rubber softener component (D): Crosslinker component (E): Flame retardant   The flame-retardant polyolefin resin according to claim 1, wherein the propylene-ethylene block copolymer in component (A) has an MFR (230 ° C, 21.2N load) of 0.05 to 2.0 g / 10 min. Composition.   The flame-retardant polyolefin resin composition according to claim 1 or 2, wherein the component (A) comprises a propylene random copolymer.   The flame-retardant polyolefin resin composition according to any one of claims 1 to 3, wherein the ethylene content in the rubber of the propylene-ethylene block copolymer in the component (A) is 72 to 90% by mass. .   The flame-retardant polyolefin resin according to any one of claims 1 to 4, wherein the component (B) comprises an ethylene-α-olefin-nonconjugated diene copolymer having an ethylene unit content of 50 to 75 mass%. Composition. The flame-retardant polyolefin resin composition according to claim 5, wherein the component (B) comprises the following component (B3).
Component (B3): a block copolymer having at least two polymer blocks P derived from a vinyl aromatic compound and at least one polymer block Q derived from a conjugated diene and / or isobutylene, and the block At least one block copolymer selected from the group consisting of block copolymers obtained by hydrogenating the copolymer   The flame-retardant polyolefin resin composition according to any one of claims 1 to 6, wherein the ratio of the component (B) to 40 parts by mass with respect to 100 parts by mass of the component (A) and the component (B) is 40 to 80 parts by mass. object.   The flame retardant polyolefin resin composition according to any one of claims 1 to 7, wherein the component (D) comprises an organic peroxide and a crosslinking aid.   The component (E) is a brominated flame retardant and / or an antimony flame retardant, and the ratio of the component (E) to 100 parts by mass of the component (A) and the component (B) is 30 to 80 parts by mass. The flame-retardant polyolefin resin composition according to any one of claims 1 to 3.   The molded object formed by shape | molding the flame-retardant polyolefin-type resin composition of any one of Claim 1 thru | or 9.   The molded article according to claim 10, which is a wire covering material.