JP2019151760A - Flame retardant resin composition and manufacturing method therefor, flame retardant resin composition pellet, and molded body and hollow molded body - Google Patents

Abstract

To provide a flame retardant resin composition capable of molding a pellet without generating phenomenon such as decomposition or foaming, even though it has good hollow moldability, excellent in flame retardancy and excellent in impact resistance, and a molded article consisting of the same.SOLUTION: There is provided a flame retardant resin composition having a specific (A) ethylene polymer and a non-halogen-based flame retardant containing (B) an organic flame retardant, with 5 pts.mass to 44 pts.mass of the (B) flame retardant based on total 100 pts.mass of the (A) ethylene polymer and the (B) flame retardant, and satisfying following properties (1) to (3). Property (1) melt flow rate (MFR) measured at temperature 190°C and load 2.16 kg is 0.05 g/10 min. to 1.0 g/10 min. Property (2) tensile breaking strength measured according to JIS K6922-2:2010 is 10 MPa to 30 MPa. Property (3) Charpy impact strength measured according to JIS K7111:2004 is 2.0 kJ/mto 10 kJ/m.SELECTED DRAWING: None

Description

  The present invention relates to a flame retardant resin composition and a method for producing the same, a flame retardant resin composition pellet, and a molded article and a hollow molded article containing the flame retardant resin composition. The present invention relates to a flame retardant resin composition containing a polymer and a flame retardant, a method for producing the same, a flame retardant resin composition pellet, and a molded article and a hollow molded article containing the flame retardant resin composition.

  Polyolefin has high transparency and flexibility, excellent chemical resistance and corrosion resistance, is inexpensive, has good moldability, and is also suitable for environmental problems and resource reusability. Widely used as daily life and industrial materials. For example, plastic bags, food packaging materials, agricultural film, tubular molded products such as pipes and hoses, shampoos, liquid detergents, and edible oil containers formed by injection molding, extrusion molding, hollow (blow) molding, etc. Applications range from large hollow products to sheet products.

  In general, polyolefins are flammable, so there are uses that require flame retardancy for disaster prevention reasons. Various flame retardants are added to improve flame retardancy, and various improvements have been made. A composition using a halogen compound as a flame retardant has a relatively low decrease in molding processability and mechanical strength of the molded product when formed into a molded product, and a molded product having a high degree of flame retardancy can be obtained. However, there is a drawback that corrosive and toxic gases are generated during molding and combustion. Therefore, the use of a non-halogen flame retardant containing no halogen is required as a flame retardant.

  Patent Document 1 discloses a first (poly) phosphate compound represented by a specific formula and a specific formula as a non-halogen flame retardant capable of imparting bleeding resistance and excellent flame retardancy. A flame retardant composition containing a specific amount of a second (poly) phosphate compound represented and a layered silicate into which an organic quaternary ammonium cation has been introduced is disclosed.

  Patent Document 2 discloses a flame retardant resin composition having flexibility while ensuring self-extinguishing properties and drip resistance, and a flame retardant resin sheet using the same.

Patent Document 3 discloses that the first (poly) phosphate compound represented by a specific formula and the second (poly) phosphate represented by a specific formula with respect to 100 parts by mass of the polyolefin resin. A weather resistant flame retardant resin composition containing 10 to 50 parts by mass of a total mixture of compounds is disclosed.
However, the required performance required for products is increasing day by day, and further performance improvement is demanded in the problems of the prior art.

JP 2015-218302 A JP 2015-34229 A JP, 2015-113413, A

Depending on the type of flame retardant, when the flame retardant resin composition is mixed and produced, phenomena such as decomposition and foaming of the flame retardant itself occur, and it is not possible to produce a material having desired characteristics such as flame retardant. Problems arise. In particular, when an organic flame retardant containing no halogen is used as the non-halogen flame retardant, the flame retardant itself is decomposed or foamed, especially when mixed with a resin having a high viscosity that is excellent in hollow moldability and impact resistance. Such a phenomenon is likely to occur, and there is a problem that the molding processability is deteriorated and the mechanical strength of the molded product is significantly reduced when it is formed into a molded product.
That is, in the conventional technology as described above, while the hollow moldability is good, the pellets can be molded without causing phenomena such as decomposition and foaming, excellent in flame retardancy, and excellent in impact resistance. In addition, a flame retardant resin composition has not been obtained yet, and is highly desired.

  In view of the above-mentioned problems of the prior art, the object of the present invention is to form a pellet without causing phenomena such as decomposition and foaming while having good hollow moldability, and has excellent flame retardancy. An object of the present invention is to provide a flame retardant resin composition excellent in impact resistance, a production method thereof, pellets thereof, and a molded article and a hollow molded article containing them.

  As a result of intensive studies to solve the above problems, the present inventors have included a specific amount of a specific ethylene polymer and a non-halogen flame retardant containing an organic flame retardant, and specific characteristics. With the flame retardant resin composition that satisfies the above requirements, the pellets can be molded without causing phenomena such as decomposition and foaming while having good hollow moldability. The present inventors have found that an excellent flame retardant resin composition and a molded product comprising the same can be obtained, and have completed the present invention.

That is, according to the first invention of the present invention, (A) at least one of an ethylene homopolymer and an ethylene-α olefin copolymer satisfying the following characteristics (i) to (ii): Containing a polymer and (B) a non-halogen flame retardant containing an organic flame retardant, with respect to a total of 100 parts by mass of the (A) ethylene polymer and the (B) flame retardant, (B ) The flame retardant is 5 parts by mass or more and 44 parts by mass or less, and a flame retardant resin composition satisfying the following characteristics (1) to (3) is provided.
Characteristic (i) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (ii) The density is 0.940 g / cm ³ or more and 0.970 g / cm ³ or less.
Characteristic (1) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (2) The tensile fracture strength measured according to JIS K6922-2: 2010 is 10 MPa or more and 30 MPa or less.
Characteristics (3) JIS K7111: Charpy impact strength measured according to 2004 is 2.0 kJ / ^{m 2} or more 10 kJ / ^{m 2} or less.

Moreover, according to the 2nd invention of this invention, the flame-retardant resin composition which satisfies the following characteristic (4) in the 1st invention is provided.
Characteristic (4) The melt tension (MT) measured at 190 ° C. is 40 mN or more.

  Moreover, according to 3rd invention of this invention, the flame-retardant resin composition in which the said organic type flame retardant contains a phosphate compound in 1st or 2nd invention is provided.

  According to a fourth invention of the present invention, in the third invention, the phosphate compound is composed of melamine orthophosphate, melamine pyrophosphate, melamine polyphosphate, piperazine orthophosphate, piperazine pyrophosphate. And a flame retardant resin composition, which is at least one compound selected from the group consisting of piperazine polyphosphate salts.

  Moreover, according to the 5th invention of this invention, the flame-retardant resin composition containing a metal soap is provided in any one of the 1st-4th invention.

  Moreover, according to the sixth invention of the present invention, in any one of the first to fifth inventions, a flame-retardant resin composition for hollow molding is provided.

  According to the seventh invention of the present invention, in the method for producing a flame retardant resin composition of any one of the first to sixth inventions, the temperature of the resin composition is 185 ° C. or higher and 208 ° C. or lower, (A) The manufacturing method of the flame-retardant resin composition characterized by mixing an ethylene polymer and the said (B) flame retardant is provided.

  Moreover, according to the 8th invention of this invention, the flame-retardant resin composition pellet formed by melt-extruding the flame-retardant resin composition of any one of the 1st-6th invention is provided.

  Moreover, according to 9th invention of this invention, the molded article containing the flame-retardant resin composition of any one of 1st-6th invention is provided.

  Moreover, according to 10th invention of this invention, the hollow molded article containing the flame-retardant resin composition of any one of 1st-6th invention is provided.

  According to the present invention, while the hollow moldability is good, the pellets can be molded without causing phenomena such as decomposition and foaming, and have excellent flame resistance and impact resistance. The resin composition, the production method thereof, the pellet thereof, and the molded article and hollow molded article containing them can be provided.

FIG. 1 is a plot diagram of typical elongation viscosity, and is a diagram for explaining a case where an inflection point of elongation viscosity is observed. FIG. 2 is a plot diagram of typical elongation viscosity, and is a diagram illustrating a case where an inflection point of elongation viscosity is not observed.

The flame-retardant resin composition of the present invention is (A) an ethylene polymer that is at least one of an ethylene homopolymer and an ethylene-α-olefin copolymer and satisfies the following characteristics (i) to (ii): And (B) a non-halogen flame retardant containing an organic flame retardant, and the (B) flame retardant with respect to a total of 100 parts by mass of the (A) ethylene polymer and the (B) flame retardant. A flame retardant is 5 mass parts or more and 44 mass parts or less, and satisfies the following characteristics (1)-(3).
Characteristic (i) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (ii) The density is 0.940 g / cm ³ or more and 0.970 g / cm ³ or less.
Characteristic (1) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (2) The tensile fracture strength measured according to JIS K6922-2: 2010 is 10 MPa or more and 30 MPa or less.
Characteristics (3) JIS K7111: Charpy impact strength measured according to 2004 is 2.0 kJ / ^{m 2} or more 10 kJ / ^{m 2} or less.
Hereinafter, the present invention will be described in detail for each item.

1. (A) Ethylene Polymer The ethylene polymer used in the present invention is at least one of an ethylene homopolymer and an ethylene-α olefin copolymer and satisfies the following characteristics (i) to (ii). .
The ethylene polymer used in the present invention preferably further satisfies the following characteristics (iii) to (iv).

Characteristic (i)
The (A) ethylene-based polymer used in the present invention has a melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg of 0.05 g / 10 min or more from the point where the effects of the present invention are exhibited. Select one that is 0.0 g / 10 min or less.
When this MFR is smaller than the lower limit, the resin pressure and the resin temperature are likely to rise, and there is a possibility that heat is easily generated during kneading or molding of the resin composition. If heat is generated during kneading of the resin composition, there is a risk of causing phenomena such as decomposition and foaming during pellet production. (A) The MFR of the ethylene polymer is preferably 0.1 g / 10 min or more, more preferably 0.2 g / 10 min or more.
On the other hand, if this MFR is larger than the above upper limit value, it tends to be drawn down and the molding processability at the time of hollow molding may be deteriorated, or the impact strength of the processed hollow molded article may not be sufficiently exhibited. (A) The MFR of the ethylene polymer is preferably 0.9 g / 10 min or less, and more preferably 0.8 g / 10 min or less.
MFR can be measured according to JIS K6922-2: 1997.
The MFR can be adjusted mainly by (A) the amount of hydrogen during polymerization of the ethylene polymer, the polymerization temperature, the use of a chain transfer agent, and the like.

Characteristic (ii)
As the (A) ethylene polymer used in the present invention, a polymer having a density of 0.940 g / cm ³ or more and 0.970 g / cm ³ or less is selected from the point of achieving the effects of the present invention.
If the density is smaller than the lower limit, hollow moldability may be deteriorated or rigidity may be insufficient. (A) The density of the ethylene-based polymer is preferably from 0.942 g / cm ³ or more, 0.945 g / cm ³ or more is more preferable.
On the other hand, if the density is larger than the above upper limit, the impact resistance performance may be reduced in the final resin composition. The density of the ethylene polymer is preferably 0.965 g / cm ³ or less, and more preferably 0.960 g / cm ³ or less.
The density can be measured by the D method according to JIS K7112: 1999.
The density can be adjusted mainly by the amount of α-olefin during the polymerization of (A) the ethylene-based polymer.

Characteristics (iii)
The (A) ethylene polymer used in the present invention preferably further satisfies the following property (iii).
Characteristic (iii): Molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 6 or more and 20 or less.
The molecular weight distribution (Mw / Mn) measured by GPC is related to improvements in various physical properties and moldability of the polymer, and is also related to improvements in the appearance of the molded product.
When the molecular weight distribution (Mw / Mn) of the (A) ethylene polymer used in the present invention is within the above range, more excellent hollow moldability can be exhibited. Moreover, when the molecular weight distribution (Mw / Mn) is 6 or more, the resin pressure at the time of molding becomes appropriate, the flow instability phenomenon hardly occurs, and it is preferable from the viewpoint of easily suppressing the appearance defect. The molecular weight distribution (Mw / Mn) is more preferably 8 or more. On the other hand, when the molecular weight distribution (Mw / Mn) is 20 or less, the impact strength as a hollow molded article is easily improved. The molecular weight distribution (Mw / Mn) is more preferably 15 or less.
The molecular weight distribution within a predetermined range can be achieved by employing a catalyst capable of controlling the molecular weight distribution and appropriate polymerization conditions. In the case of a bimodal or multimodal polymer, it can be controlled by adjusting the molecular weight of each component.

The molecular weight and molecular weight distribution can be measured by gel permeation chromatography (GPC) under the following conditions.
[Measurement condition]
Model used: Alliance GPCV2000 manufactured by Japan Waters Co., Ltd. Measurement temperature: 145 ° C
Solvent: orthodichlorobenzene (ODCB)
Column: Showex Denko Shodex HT-806M x 2 + HT-G
Flow rate: 1.0 mL / min Injection rate: 0.3 mL

[Sample preparation]
A 3 mL sample and 3 mL of orthodichlorobenzene (containing 0.1 mg / mL 1,2,4-trimethylphenol) were weighed into a 4 mL vial, and capped with a resin screw cap and a Teflon (registered trademark) septum. Then, it melt | dissolves for 2 hours using the SSC-9300 type | mold high temperature shaker by Senshu Scientific which set the temperature to 150 degreeC. After completion of dissolution, it is visually confirmed that there are no insoluble components.
[Create calibration curve]
Four 4 mL glass bottles are prepared, and 0.2 mg each of monodisperse polystyrene standard samples or n-alkanes of the combinations (1) to (4) below are weighed, followed by orthodichlorobenzene (0.1 mg / mL). SSC-9300 type manufactured by Senshu Kagaku Co., Ltd., which was set at a temperature of 150 ° C. after weighing 3 mL of (including 1,2,4-trimethylphenol) and capping with a resin screw cap and a Teflon (registered trademark) septum. Dissolve for 2 hours using a high temperature shaker.
(1) Shodex S-1460, S-66.0, n-eicosane (2) Shodex S-1950, S-152, n-tetracontane (3) Shodex S-3900, S-565, S -5.05
(4) Shodex S-7500, S-1010, S-28.5
The vial containing the sample solution is set in the apparatus, the measurement is performed under the above-mentioned conditions, and the chromatogram (the retention time and the differential refractometer detector response data set) is recorded at a sampling interval of 1 second. From the obtained chromatogram, the retention time (peak apex) of each polystyrene standard sample is read and plotted against the logarithmic value of the molecular weight. Here, the molecular weights of n-eicosane and n-tetracontane are 600 and 1200, respectively. A nonlinear least square method is applied to this plot, and the obtained quartic curve is used as a calibration curve.

[Calculation of molecular weight]
Measure under the above conditions and record the chromatogram at a sampling interval of 1 second.
From this chromatogram, Sadao Mori “Size Exclusion Chromatography” (Kyoritsu Shuppan), Chapter 4, p. The differential molecular weight distribution curve and average molecular weight values (Mn, Mw, and Mz) are calculated by the method described in 51-60. However, in order to correct the molecular weight dependency of dn / dc, the height H from the baseline in the chromatogram is corrected by the following equation. Chromatogram recording (data acquisition) and average molecular weight calculation are performed using an in-house program (created with Microsoft Visual Basic 6.0 from Microsoft) on a PC in which Microsoft Windows (registered trademark) XP is installed.
H ′ = H / [1.032 + 189.2 / M (PE)]
In addition, the following formula is used for molecular weight conversion from polystyrene to polyethylene.
M (PE) = 0.468 × M (PS)

Characteristics (iv)
The (A) ethylene polymer used in the present invention preferably further satisfies the following property (iv).
Characteristic (iv): The melt tension (MT) measured at 190 ° C. is 40 mN or more and 300 mN or less.
When the melt tension (MT) of the (A) ethylene polymer used in the present invention is within the above range, it is difficult to draw down, and more excellent hollow moldability can be exhibited.
The melt tension is more preferably 60 mN or more, and still more preferably 80 mN or more.

The melt tension is determined by measuring the stress when the molten ethylene polymer is stretched at a constant speed, and can be measured under the following conditions.
[Measurement condition]
Model used: Toyo Seiki Seisakusho, Capillograph 1B
Nozzle diameter: 2.095mm
Nozzle length: 8.0mm
Inflow angle: 180 ° (flat)
Extrusion speed: 15 mm / min Take-off speed: 6.5 m / min Measuring temperature: 190 ° C.

Characteristic (v)
The (A) ethylene polymer used in the present invention preferably further satisfies the following property (v).
Characteristic (v): Glass transition temperature (Tg) is 25 ° C. or lower.
When the glass transition temperature (Tg) of the (A) ethylene polymer used in the present invention is within the above range, it can contribute to safety at the time of destruction of the molded product.
The glass transition temperature (Tg) is preferably 0 ° C. or lower, more preferably −30 ° C. or lower, and still more preferably −50 ° C. or lower.
The glass transition temperature (Tg) is related to the fracture mode of the molded body, and when it is higher than the usage environment of the molded body, it is easy to break like glass and form a sharp fractured surface. If this is the case, it may lead to injury.
The glass transition temperature (Tg) can be adjusted mainly from the types and composition ratios of the polymer monomer and comonomer, and the glass transition temperature (Tg) of the ethylene-based polymer is known to be low, which is preferable.

The glass transition temperature (Tg) can be measured using a differential scanning calorimeter under the following conditions.
[Measurement condition]
About 10 mg of the sample was heated from 30 ° C. to 200 ° C. at a heating rate of 50 ° C./min in a nitrogen atmosphere, and held at that temperature for 10 minutes. Furthermore, after cooling to -75 ° C. at a temperature lowering rate of 10 ° C./min, holding at that temperature for 5 minutes, the temperature was raised to 200 ° C. at a temperature rising rate of 10 ° C./min. The glass transition temperature (Tg) is sensed in such a manner that the DSC curve is bent due to the change in specific heat and the base line moves in parallel during the second temperature increase. The glass transition temperature (Tg) can be determined as the temperature at the intersection of the tangent to the base line, which is lower than the bending, and the tangent at the point where the inclination is maximum at the bent portion.

(A) An ethylene polymer is an ethylene homopolymer or ethylene and an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene. , 1-octene and the like. Also, copolymerization with a diene for the purpose of modification is possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like. The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content is 0 to 40 mol%, preferably 0 to 30 mol%.
In addition, ethylene manufactured from the crude oil derived from a usual fossil raw material may be sufficient as ethylene used for the (A) ethylene-type polymer used for this invention, and ethylene derived from a plant may be sufficient as it. Examples of the plant-derived ethylene and polyethylene include ethylene and polymers thereof described in JP-T 2010-511634. Plant-derived ethylene and its polymers have the property of carbon neutral (does not use fossil raw materials and does not lead to an increase in carbon dioxide in the atmosphere), and can provide environmentally friendly products.

  The (A) ethylene polymer used in the present invention can be polymerized using various polymerization catalysts as long as the above properties can be satisfied. The ethylene-based polymer (A) used in the present invention can be produced by polymerization using a conventionally known catalyst such as a chromium-containing catalyst such as a Philips catalyst, a Ziegler-Natta catalyst, a metallocene catalyst, etc., preferably Polymerization can be carried out using a chromium-containing catalyst and / or a Ziegler-Natta catalyst. This is because polyethylene derived from a chromium catalyst has a relatively wide molecular weight distribution and has a characteristic of being easy to be hollow-molded from a molecular structure having a long-chain branched structure, specifically, a high melt tension and swell ratio. . In addition, the polyethylene derived from the Ziegler-Natta catalyst has a reasonably wide molecular weight distribution, and has excellent melt molding processing characteristics and mechanical strength.

  A preferable example of the chromium-based catalyst is a chromium-based catalyst in which at least a part of chromium atoms becomes hexavalent by supporting a chromium compound on an inorganic oxide support and calcination activation in a non-reducing atmosphere. It is known as a catalyst and is known. An overview of this catalyst can be found in M.C. P. McDaniel, Advances in Catalysis, Volume 33, 47, 1985, Academic Press Inc. , M.M. P. McDaniel, Handbook of Heterogeneous Catalysis, 2400, 1997, VCH, M.M. B. Welch et al., Handbook of Polyolefins: Synthesis and Properties, p. 21, 1993, described in documents such as Marcel Dekker.

The inorganic oxide carrier is preferably a metal oxide of Group 2, 4, 13 or 14 of the periodic table. Specific examples include magnesia, titania, zirconia, alumina, silica, tria, silica-titania, silica-zirconia, silica-alumina, or mixtures thereof. Of these, silica, silica-titania, silica-zirconia, and silica-alumina are preferable. In the case of silica-titania, silica-zirconia, silica-alumina, titanium, zirconium or aluminum atoms as metal components other than silica are 0.2 to 10% by mass, preferably 0.5 to 7% by mass, more preferably 1 to Those containing 5% by mass are used.
The production method, physical properties and characteristics of the support suitable for these chromium-based catalysts are described in C.I. E. Marsden, Preparation of Catalysts, Volume V, p. 215, 1991, Elsevier Science Publishers, C.I. E. Marsden, Plastics, Rubber and Composites Processing and Applications, Volume 21, p. 193, 1994, and the like.

The specific surface area of the support of the chromium-based catalyst before the activation of the firing is 250 to 1000 m ² / g, preferably 300 to 900 m ² / g, and more preferably 400 to 800 m ² / g. It is preferred to select a carrier. When the specific surface area is less than 250 m ² / g, it is considered that the molecular weight distribution is narrow and long-chain branching is increased, but both durability and impact resistance may be lowered. In addition, a carrier having a specific surface area exceeding 1000 m ² / g may be difficult to produce.

The pore volume of the inorganic oxide support, as in the case of common chromium-based catalyst carrier used, 0.5~3.0cm ³ / g, preferably 1.0~2.0cm ³ / g More preferably, those in the range of 1.2 to 1.8 cm ³ / g are used. When the pore volume is less than 0.5, the pores become small due to the polymer during polymerization, and the monomer cannot be diffused, which may reduce the activity. A carrier having a pore volume exceeding 3.0 cm ³ / g may be difficult to produce.
The average particle diameter of the inorganic oxide carrier is 10 to 200 μm, preferably 20 to 150 μm, more preferably 30 to 100 μm, like the carrier used for general chromium-based catalysts.

  A chromium compound is supported on the inorganic oxide support. The chromium compound may be a compound in which at least a part of chromium atoms becomes hexavalent by firing activation in a non-reducing atmosphere after loading, such as chromium oxide, chromium halide, oxyhalide, chromate. , Dichromate, nitrate, carboxylate, sulfate, chromium-1,3-diketo compound, chromate, and the like. Specifically, chromium trioxide, chromium trichloride, chromyl chloride, potassium chromate, ammonium chromate, potassium dichromate, chromium nitrate, chromium sulfate, chromium acetate, tris (2-ethylhexanoate) chromium, chromium acetyl Examples include acetonate and bis (tert-butyl) chromate. Of these, chromium trioxide, chromium acetate, and chromium acetylacetonate are preferable. Even when a chromium compound having an organic group such as chromium acetate or chromium acetylacetonate is used, the organic group part burns by firing activation in a non-reducing atmosphere described later, and finally chromium trioxide is used. It is known that it reacts with the hydroxyl group on the surface of the inorganic oxide carrier in the same manner as in the case of at least some of the chromium atoms and becomes hexavalent and is fixed in the structure of chromate (VJ Ruddick). Et al., J. Phys. Chem., Volume 100, 11062, 1996, SM Augustine et al., J. Catal., Volume 161, 641, 1996).

  The chromium compound can be supported on the inorganic oxide support by a known method such as impregnation, solvent distillation, sublimation, etc., and an appropriate method may be used depending on the kind of the chromium compound to be used. The amount of the chromium compound to be supported is 0.2 to 2.0% by mass, preferably 0.3 to 1.7% by mass, more preferably 0.5 to 1.5% by mass with respect to the carrier as chromium atoms. is there.

After the chromium compound is supported, it is fired and activated. The calcination activation can be performed in a non-reducing atmosphere substantially free of moisture, such as oxygen or air. At this time, an inert gas may coexist. Preferably, it is performed in a fluidized state using sufficiently dried air through which molecular sieves or the like are circulated. The firing activation is performed at 350 to 900 ° C, preferably 420 to 850 ° C, more preferably 450 to 800 ° C, for 30 minutes to 48 hours, preferably 1 hour to 36 hours, more preferably 2 hours to 24 hours. By this firing activation, at least a part of the chromium atoms of the chromium compound supported on the inorganic oxide support is oxidized to be hexavalent and chemically fixed on the support. If it is carried out below 350 ° C., the polymerization activity may be lost. On the other hand, if firing activation is performed at a temperature exceeding 900 ° C., sintering may occur and the activity may be reduced.
By using the chromium catalyst thus obtained, an ethylene polymer suitable for the (A) ethylene polymer can be produced.

On the other hand, the Ziegler-Natta catalyst is a polymerization catalyst having titanium as an active species, and can be appropriately selected from conventionally known catalysts. As the Zigner-ratta catalyst, a magnesium / titanium composite type Ziegler-Natta catalyst is particularly preferable. The magnesium-titanium composite type Ziegler-Natta catalyst is excellent in particle shape and has excellent polymerization activity.
The magnesium / titanium composite type Ziegler-Natta catalyst is preferably further modified with an organoaluminum compound. By using such a modified Ziegler-Natta catalyst, polyethylene with few short chain branches can be produced. A magnesium-titanium composite type Ziegler-Natta catalyst modified with an organoaluminum compound can be produced with reference to JP 2012-72229 A.

  (A) A conventionally well-known method can be used suitably for the polymerization method of an ethylene-type polymer. For example, any method such as slurry polymerization, liquid phase polymerization method such as solution polymerization or gas phase polymerization method can be adopted, but the slurry polymerization method is particularly preferable, slurry polymerization method using a pipe loop reactor, Any of the slurry polymerization methods using an autoclave reactor can be used. Among these, a slurry polymerization method using a pipe loop reactor is preferable (details of a pipe loop reactor and slurry polymerization using the reactor are described in Kazuo Matsuura and Naotaka Mikami, “Polyethylene Technology Reader”, 148 pages, 2001 (It is described in the Industrial Research Committee).

The liquid phase polymerization method is usually performed in a hydrocarbon solvent. As the hydrocarbon solvent, inert hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, decane, cyclohexane, benzene, toluene, and xylene are used alone or as a mixture. As the gas phase polymerization method, a commonly known polymerization method such as a fluidized bed or a stirring bed can be employed in the presence of an inert gas, and a so-called condensing mode in which a medium for removing heat of polymerization coexists may be employed. .
The polymerization temperature in the liquid phase polymerization method is generally 0 to 300 ° C., practically 20 to 200 ° C., preferably 40 to 180 ° C., more preferably 50 to 150 ° C., and particularly preferably 70 to 110 ° C. ° C. The catalyst concentration and ethylene concentration in the reactor may be any concentration sufficient to allow the polymerization to proceed. For example, the catalyst concentration can range from about 0.0001 to about 5% by weight based on the weight of the reactor contents in the case of liquid phase polymerization. Similarly, the ethylene concentration can range from about 1% to about 10% based on the weight of the reactor contents for liquid phase polymerization. Similarly, in the case of gas phase polymerization, the ethylene concentration can be in the range of 0.1 to 10 MPa as the total pressure. It is also possible to carry out polymerization in the presence of hydrogen, and in order to produce an ethylene polymer with a good balance of durability, impact resistance, and rigidity, conditions under which hydrogen and ethylene are in a specific ratio It is better to polymerize under. Hydrogen generally functions as a so-called chain transfer agent for adjusting the molecular weight.

  As a polymerization method, not only single-stage polymerization in which an ethylene-based polymer is produced using one reactor, but also at least two or more reactions in order to improve the production amount or broaden the molecular weight distribution or comonomer composition distribution. Multistage polymerization can also be carried out by connecting the vessels in series or / and in parallel. In the case of multistage polymerization, serial multistage polymerization is preferred in which a plurality of reactors are connected and the reaction mixture obtained by polymerization in the first stage reactor is continuously supplied to the second and subsequent reactors. In the serial multistage polymerization method, the polymerization reaction mixture in the preceding reactor is transferred to the subsequent reactors by continuous discharge through a connecting pipe.

A specific embodiment of the multi-stage polymerization will be described by taking a two-stage polymerization using two reactors as an example.
In the case of two-stage polymerization, the first stage reactor and the second stage reactor may be produced under the same polymerization conditions, or the same MFR and density ethylene in the first stage reactor and the second stage reactor. Although a polymer may be produced, when broadening the molecular weight distribution, it is preferable to make a difference in the molecular weight of the ethylene polymer produced in both reactors. In any production method of producing a high molecular weight component in the first stage reactor, a low molecular weight component in the second stage reactor, or a low molecular weight component in the first stage reactor, and a high molecular weight component in the second stage reactor, respectively. Although the method of producing high molecular weight components in the first stage reactor and low molecular weight components in the second stage reactor requires an intermediate hydrogen flash tank for the transition from the first stage to the second stage. Therefore, it is more preferable in terms of productivity.

In the first stage, copolymerization of ethylene alone or optionally other α-olefin as a comonomer is carried out while adjusting the molecular weight according to the ratio of the hydrogen concentration to the ethylene concentration, the polymerization temperature or both, and the comonomer concentration of ethylene. The polymerization reaction is carried out while adjusting the density by the weight ratio to the concentration.
In the second stage, there are hydrogen in the reaction mixture flowing from the first stage and ethylene flowing in the same, but new hydrogen and ethylene can be added as necessary. Therefore, also in the second stage, the polymerization reaction can be carried out while adjusting the molecular weight by adjusting the ratio of hydrogen concentration to ethylene concentration, polymerization temperature or both, and adjusting the density by adjusting the ratio of comonomer concentration to ethylene concentration. For organometallic compounds such as catalysts and organoaluminum compounds, not only does the polymerization reaction continue in the second stage with the catalyst flowing in from the first stage, but also a new catalyst, organometallic compounds such as organoaluminum compounds in the second stage. Compounds or both may be supplied.

The ethylene-based polymer (A) used in the present invention is polymerized successively in a single polymerizer, a plurality of reactors connected in series or in parallel, and a plurality of polymers as long as the range specified in the present invention is satisfied. What mixed after polymerizing ethylene polymer separately may be used.
The (A) ethylene polymer used in the present invention is preferably a mixture of an ethylene polymer derived from a chromium catalyst and an ethylene polymer derived from a Ziegler-Natta catalyst, for example, because it easily satisfies the specified range in the present invention. Used for.

2. (B) Flame retardant The (B) flame retardant used in the present invention is a halogen-free non-halogen flame retardant, and includes an organic flame retardant.
The organic flame retardant used in the present invention is an organic flame retardant containing no halogen. For example, any of various organic flame retardants such as phosphorus, guanidine, and melamine cyanuric acid derivatives can be used.
As the organic flame retardant, a phosphorous flame retardant composed of an organic phosphate ester compound, a phosphate compound, and a mixture thereof is preferable because it has a high effect of flame retardancy, and particularly includes a phosphate compound. preferable.

  Examples of the organic phosphate compound include triphenyl phosphate, tricresyl phosphate, bisphenol-A-bisdiphenyl phosphate, resorcinol-bisdiphenyl phosphate, and the like.

Examples of the phosphate compound include a salt obtained by reacting a phosphate compound with an amine compound having at least one amino group in the molecule. A phosphate compound can be used individually or in combination of 2 or more types.
As a phosphate compound, a compound or mixture containing a phosphorus component that promotes carbonization and a nitrogen component that promotes extinguishing / foaming functions as an intumescent flame retardant and is preferably used from the viewpoint of high flame retardancy. It is done. On the other hand, since such an intumescent flame retardant is easily foamed by heating or the like, it is particularly difficult to mix with an ethylene polymer satisfying the above-mentioned specific characteristics (i) to (ii). Met.

  Examples of the phosphoric acid compound include polyphosphoric acid such as pyrophosphoric acid and triphosphoric acid, and monophosphoric acid such as orthophosphoric acid.

Examples of the amine compound include N, N, N ′, N′-tetramethyldiaminomethane, ethylenediamine, N, N′-dimethylethylenediamine, N, N′-diethylethylenediamine, N, N-dimethylethylenediamine, N, N-diethylethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetraethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethylenediamine, Aliphatic diamines such as pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane and 1,10-diaminodecane, piperazine, trans-2,5-dimethyl Piperazine, 1,4-bis (2-aminoethyl) pipe Amine, amine compounds containing a piperazine ring such as 1,4-bis (3-aminopropyl) piperazine, melamine, acetoguanamine, benzoguanamine, acrylic guanamine, 2,4-diamino-6-nonyl-1,3,5-triazine 2,4-diamino-6-hydroxy-1,3,5-triazine, 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3 , 5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-iso Propoxy-1,3,5-triazine, 2,4-diamino-6-mercapto-1,3,5-triazine and 2-amino-4,6-dimercapto-1,3,5-triazine Examples include amine compounds containing a triazine ring such as azine.
The phosphoric acid compound preferably contains polyphosphoric acid. That is, the phosphate compound preferably contains a polyphosphate. In this case, higher flame retardancy can be obtained as compared with the case where the phosphate compound does not contain polyphosphoric acid.

The phosphate compound used in the flame retardant of the present invention is selected from the group consisting of melamine orthophosphate, melamine pyrophosphate, melamine polyphosphate, piperazine orthophosphate, piperazine pyrophosphate, and piperazine polyphosphate. Preferably, the compound is at least one compound.
Among them, the phosphate compound used in the flame retardant of the present invention includes a melamine salt (b-1) selected from the group consisting of melamine orthophosphate, melamine pyrophosphate, and melamine polyphosphate, and piperazine orthophosphate. A mixture with a piperazine salt (b-2) selected from the group consisting of a salt, a piperazine pyrophosphate salt, and a piperazine polyphosphate salt is preferable.
Moreover, it is preferable that the content ratio (mass standard) of said (b-1) and said (b-2) is (b-1) / (b-2) = 20 / 80-50 / 50, More preferably, (b-1) / (b-2) = 30/70 to 50/50.

As the melamine salt, melamine pyrophosphate is preferable from the viewpoint of flame retardancy. When using the said melamine salt with a mixture, it is so preferable that the content rate of melamine pyrophosphate is high. The molar ratio of melamine pyrophosphate to pyrophosphoric acid to melamine is preferably 1: 1.5 to 1: 2.5, and most preferably 1: 2.
These salts of phosphoric acid and melamine can also be obtained by reacting the corresponding phosphoric acid or phosphate and melamine, respectively, but the melamine salt used in the present invention is obtained by heat condensation of 1-melamine orthophosphate. The resulting melamine pyrophosphate or melamine polyphosphate is preferred, and melamine pyrophosphate is particularly preferred.

As the piperazine salt, piperazine pyrophosphate is preferable from the viewpoint of flame retardancy, and when used in a mixture, the higher the content of piperazine pyrophosphate, the more preferable. Further, the ratio of pyrophosphoric acid to piperazine in piperazine pyrophosphate is preferably 1: 0.5 to 1: 1.5 in molar ratio, and more preferably 1: 1.
These phosphoric acid and piperazine salts can also be obtained by reacting the corresponding phosphoric acid or phosphate and piperazine, respectively. However, the piperazine salt used in the present invention is obtained by heat-condensing 1 piperazine 2 orthophosphate. Piperazine pyrophosphate or piperazine polyphosphate obtained above is preferable, and piperazine pyrophosphate is particularly preferable.

  As a commercial item of a flame retardant containing a phosphate compound, manufactured by ADEKA Corporation, trade names: ADK STAB FP2000, FP2100, FP2200, and the like can be given.

As long as the (B) flame retardant used in the present invention is a halogen-free non-halogen flame retardant, it may be composed of only an organic flame retardant, and further with an inorganic flame retardant or a flame retardant aid. It may be composed of a mixture.
As long as the effect of the present invention is not impaired, for example, a layered silicate introduced with an organic quaternary ammonium cation as described in JP-A-2015-218302, a flame retardant aid such as zinc oxide, Anti-drip agents such as silicone rubbers and layered silicates may further be included.

  The flame retardant (B) used in the present invention preferably contains 80% by mass or more, more preferably 85% by mass or more, and 90% by mass or more of the organic flame retardant in the flame retardant. It is even more preferable. Among them, the flame retardant (B) used in the present invention preferably contains 80% by mass or more of the phosphate compound in the flame retardant, more preferably 85% by mass or more, and 90% by mass or more. It is still more preferable to contain.

3. (C) Other components The flame-retardant resin composition of the present invention may further contain other components as long as the effects of the present invention are not impaired.
Examples of other components include dispersants, lubricants, antioxidants, ultraviolet absorbers, hindered amine light stabilizers, anti-aging agents, antistatic agents, antiblocking agents, nucleating agents, antifogging agents, and organic or inorganic pigments. Known additives such as other polyolefins that do not correspond to ethylene copolymers, known resins such as thermoplastic resins, and fibrous, plate-like, granular, and powder-like reinforcing materials used for reinforcing synthetic resins Can be added. Specific examples of the reinforcing material include inorganic fibrous reinforcing materials such as glass fibers and carbon fibers, organic fibrous reinforcing materials such as polyester fibers and nylon fibers, glass flakes, non-swelling mica, and plate shapes such as graphite. A granular reinforcing material is mentioned.

In order to improve the dispersibility of the (B) flame retardant in the (A) ethylene polymer, the flame retardant resin composition of the present invention preferably contains a dispersant. (B) By improving the dispersibility of the flame retardant in the (A) ethylene polymer, the tensile fracture strength, impact strength, and melt tension of the flame retardant resin composition are improved.
As the dispersant, a surfactant having a hydrophilic group and a hydrophobic group is used, and is classified according to molecular weight or ionicity, and examples thereof include cationic, anionic, and nonionic types. Low molecular weight compounds such as alkylbenzene sulfonate (LAS), branched alkylbenzene sulfonate (ABS), polyoxyethylene alkyl sulfate (AES), alcohol ethoxylate (AE), maleic anhydride, acrylic acid, acrylamide And the like having a polymer as a main component such as a polymer of a monomer having a functional group.
As a dispersant, depending on the type of flame retardant, from the viewpoint of affinity with ethylene polymers, nonionic surfactants, ethylene / maleic anhydride copolymers containing a methylene chain in the molecular structure, etc. The main component is preferred.

Since the flame retardant resin composition of the present invention uses an ethylene polymer that satisfies the characteristics (i) to (ii), local heat generation tends to occur at the die outlet during pellet production. Therefore, it is preferable that the flame retardant resin composition of the present invention further contains a lubricant. By containing a lubricant, the occurrence of mayani during pellet production is suppressed, enabling continuous production for a long period of time, and the appearance and physical properties of molded products molded from the pellets by mixing them with the pellets. Can be suppressed.
Examples of the lubricant include hydrocarbon waxes, aliphatic amide waxes, fatty acid ester waxes, metal soaps, polymer lubricants represented by fluorine resins and acrylic resins, and the like. Metal soap is particularly preferable because it has a high effect of reducing the scum, is hardly thermally deteriorated during pellet production, and can easily prevent the heat-degraded lubricant from being mixed into the product.
Further, the lubricant may be added in advance mixed with an ethylene copolymer or the like.

The flame retardant resin composition of the present invention preferably contains an antioxidant in order to suppress deterioration due to effects such as heat and mechanical shearing force.
Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, and thioether antioxidants. Among them, hindered phenolic antioxidants are preferably used.
As a hindered phenolic antioxidant, for example, as a hindered phenolic antioxidant, for example, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (product) Name: Irganox 1010, manufactured by BASF), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 2,4,6-tris (4-hydroxy-3, 5-di-tert-butylbenzyl) mesitylene, 6- (4-hydroxy-3,5-di-tert-butylanilino) -2,4-bis (octylthio) -1,3,5-triazine, 2,2 ′ -Thiodiethylbis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,2-bis [3- (4-hydroxy-3,5-di-tert-butylphenyl) propionyl] hydrazine, octyl 3- (4-hydroxy-3,5-diisopropylphenyl) propionate, 4,6-bis (octylthiomethyl) ) -O-cresol, N, N′-hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanamide], 1,6-hexanediol bis [3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate], 1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8, 10-tetraoxaspiro [5.5] undecane, bis (3-tert-butyl-4-hydroxy-5-methylbenzenepropionic acid) Ethylenebis (oxyethylene), 1,3,5-tris [[4- (1,1-dimethylethyl) -3-hydroxy-2,6-dimethylphenyl] methyl] -1,3,5-triazine-2 , 4, 6 (1H, 3H, 5H) -trione and the like. In addition, oligomer-type and polymer-type compounds having a hindered phenol structure can also be used.

4). Flame Retardant Resin Composition The flame retardant resin composition of the present invention is 5 parts by mass of the (B) flame retardant with respect to a total of 100 parts by mass of the (A) ethylene polymer and the (B) flame retardant. It is a composition containing at least 44 parts by weight. From the viewpoint of flame retardancy and impact resistance, the flame retardant resin composition of the present invention is based on (B) the total of 100 parts by mass of the (A) ethylene polymer and the (B) flame retardant. It is more preferable that the flame retardant is a composition containing from 12 parts by weight to 40 parts by weight.

  In the flame retardant resin composition of the present invention, an additive may not be included among the other components, but the content of the additive when included is the (A) ethylene polymer and The total amount of the (B) flame retardant is preferably 0.01 parts by mass or more and 0.5 parts by mass or less, and more preferably 0.05 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass in total. preferable.

Since the flame retardant resin composition of the present invention is excellent in flame retardancy and hollow moldability, the (A) ethylene polymer and the (B) flame retardant in the flame retardant resin composition excluding the reinforcing material. The total content of is preferably 95% by mass or more, and more preferably 98% by mass or more.
Furthermore, the flame retardant resin composition of the present invention is a total of the (A) ethylene polymer and the (B) flame retardant in the flame retardant resin composition because it is excellent in flame retardancy and hollow moldability. The content is preferably 95% by mass or more, and more preferably 98% by mass or more.

It is important that the flame retardant resin composition of the present invention satisfies the following characteristics (1) to (3).
Characteristic (1) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (2) The tensile fracture strength measured according to JIS K6922-2: 2010 is 10 MPa or more and 30 MPa or less.
Characteristics (3) JIS K7111: Charpy impact strength measured according to 2004 is 2.0 kJ / ^{m 2} or more 10 kJ / ^{m 2} or less.

Characteristics (1)
The flame retardant resin composition of the present invention has an MFR of 0.05 g / 10 min or more and 1.0 g / 10 min or less.
If this MFR is smaller than the above lower limit value, the fluidity will decrease, which may increase the amount of resin heat generated by the extruder motor load and shear during molding, and the flow instability phenomenon tends to occur. There is a risk of damaging the appearance. The MFR of the flame retardant resin composition is preferably 0.08 g / 10 min or more, and more preferably 0.1 g / 10 min or more.
On the other hand, if this MFR is larger than the above upper limit value, it tends to be drawn down and the molding processability at the time of hollow molding is deteriorated, impact resistance cannot be achieved, and long-term durability may be lowered. The MFR of the flame retardant resin composition is preferably 0.7 g / 10 min or less, and more preferably 0.5 g / 10 min or less.
The MFR of the flame retardant resin composition can be adjusted by (A) the hydrogen amount and temperature of the ethylene polymer, and the blending amount and mixing method of the (A) ethylene polymer and (B) flame retardant. .
The characteristic (1) can be measured in the same manner as the characteristic (i) of the (A) ethylene polymer.

Characteristic (2)
The flame retardant resin composition of the present invention has a tensile fracture strength measured according to JIS K6922-2: 2010 of 10 MPa or more and 30 MPa or less.
If the tensile fracture strength is less than the above lower limit value, it becomes difficult to maintain a sufficient strength as a molded body, or it becomes necessary to increase the thickness of the molded product in order to maintain the strength. The tensile fracture strength of the flame retardant resin composition is preferably 12 MPa or more, and more preferably 15 MPa or more.
On the other hand, when the tensile fracture strength is less than or equal to the above upper limit value, the melting point of the ethylene polymer falls within the temperature range suitable for molding, and it becomes easy to maintain the balance between rigidity and moldability. The tensile fracture strength of the flame retardant resin composition may be 25 MPa or less, or 22 MPa or less.
The tensile fracture strength of the flame retardant resin composition can be adjusted by the density of (A) the ethylene polymer and the blending amount and mixing method of the (A) ethylene polymer and (B) flame retardant. . Moreover, even if the blending amount of the (A) ethylene polymer and the (B) flame retardant is the same, the flame retardant is not evenly dispersed or the tensile fracture strength is lowered by foaming. Therefore, it also serves as an index indicating the degree of dispersion and foaming of the flame retardant.
The tensile breaking strength can be measured by preparing a test piece in accordance with JIS K6922-2.

Characteristic (3)
The flame retardant resin composition of the present invention, JIS K7111: the Charpy impact strength Charpy impact strength is measured according is 2.0 kJ / ^{m 2} or more 10 kJ / ^{m 2} or less in 2004 is smaller than the above lower limit In such a case, the impact resistance of the molded product may be insufficient. The Charpy impact strength of the flame-retardant resin composition is preferably 2.3 kJ / ^{m 2} or more, 3.0kJ / ^{m 2} or more is more preferable.
On the other hand, when the Charpy impact strength is not more than the above upper limit value, the melt flow rate of the ethylene polymer falls within the range of fluidity suitable for molding, and it becomes easy to maintain the balance between impact resistance and moldability.
The Charpy impact strength can be adjusted by (A) the molecular weight and molecular weight distribution of the ethylene polymer, and the blending amount and mixing method of (A) the ethylene polymer and (B) the flame retardant.
The Charpy impact strength conforms to JIS K7111: 2004, and a test piece of type 1 is prepared. The striking direction is edgewise and the notch type is type A (0.25 mm). Can be measured.

Characteristic (4)
The flame retardant resin composition of the present invention preferably satisfies the following property (4) from the viewpoint of hollow moldability such as drawdown resistance.
Characteristics (4) density of 0.97 g / cm ³ or more 1.20 g / cm ³ or less.
If the density of the flame retardant resin composition of the present invention is smaller than the above lower limit value, it means that the amount of the flame retardant is small, and the flame retardancy may be insufficient. The density of the flame retardant resin composition is preferably 0.98 g / cm ³ or more, and more preferably 0.99 g / cm ³ or more.
On the other hand, if the density of the flame retardant resin composition is larger than the above upper limit value, it means that flame retardancy is excessively blended, and impact resistance performance may be lowered. The density of the flame retardant resin composition is preferably 1.19 g / cm ³ or less, more preferably 1.18 g / cm ³ or less.
The density of the flame retardant resin composition depends on (A) the density of the ethylene polymer, (B) the density of the flame retardant, and the blending amount and mixing method of the (A) ethylene polymer and (B) the flame retardant. Can be adjusted.
The density of the flame retardant resin composition can be measured in the same manner as the density of the characteristic (ii) of the (A) ethylene polymer.

Characteristic (5)
The flame retardant resin composition of the present invention preferably satisfies the following property (5) from the viewpoint of hollow moldability such as drawdown resistance.
Characteristic (5): The melt tension (MT) measured at 190 ° C. is 40 mN or more. The melt tension is more preferably 50 mN or more, and still more preferably 60 mN or more.
The melt tension of the flame retardant resin composition can be adjusted by (A) the melt tension of the ethylene polymer, and the blending amount and mixing method of the (A) ethylene polymer and (B) the flame retardant.
The melt tension of the flame retardant resin composition can be measured in the same manner as the melt tension of the characteristic (iv) of the (A) ethylene polymer.

Characteristic (6)
The flame retardant resin composition of the present invention preferably further satisfies the following property (6) from the viewpoint of maintaining a balance between the rigidity of the molded product and an appropriate molding temperature during molding.
Characteristic (6): Melting point (Tm) is 120 ° C. or higher. The melting point (Tm) is more preferably 125 ° C. or higher, and still more preferably 130 ° C. or higher.
The melting point (Tm) can be measured with a differential scanning calorimeter (DSC). About 5 mg of a 0.2 mm-thick press sheet cut into a circle is packed in an aluminum pan and placed at 200 ° C. in a nitrogen atmosphere. After heating up to 10 ° C./min, hold at the same temperature for 5 minutes, cool to 30 ° C. at 10 ° C./min, then hold at the same temperature for 5 minutes, then heat up to 200 ° C. at 10 ° C./min. The temperature at which the change in the maximum value can be obtained as the melting point (Tm).

Characteristic (7)
The flame retardant resin composition of the present invention preferably satisfies the following property (7) from the viewpoint of hollow moldability.
Characteristic (7): Both elongation viscosity η (t) (unit: Pa · second) and elongation time t (unit: second) measured at a temperature of 170 ° C. and an elongation strain rate of 0.1 (unit: 1 / second) In the logarithmic plot, an inflection point of elongational viscosity due to strain hardening is observed.
In the present specification, the presence or absence of an inflection point of elongational viscosity due to strain hardening can be observed in the measurement of the strain hardening degree.
Regarding the method for measuring the strain hardening degree, as long as the uniaxial extensional viscosity can be measured, the same value can be obtained in principle by any method. For example, the measurement method and the measuring instrument are disclosed in the known document: Polymer 42 (2001) 8663 Details are described.
In the measurement of the resin composition according to the present invention, preferred measurement methods and measuring instruments include the following.

Measuring method:
・ Device: Ares manufactured by Rheometrics
-Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
・ Measurement temperature: 170 ℃
-Strain rate: 0.1 / second-Preparation of test piece: Press-molded to produce a sheet of 18 mm x 10 mm and a thickness of 0.7 mm.

Calculation method:
The elongational viscosity at 170 ° C. and a strain rate of 0.1 / second is plotted as a log-log graph of time t (second) on the horizontal axis and elongation viscosity η (t) (Pa · second) on the vertical axis. On the log-log graph, the maximum elongation viscosity until strain becomes 4.0 after strain hardening is η _Max (t1) (t1 is the time when the maximum elongation viscosity is shown), and the extension viscosity before strain hardening. when the approximate line and η _linear (t), defines the value calculated as _{η Max (t1) / η linear} (t1) strain hardening degree and (.lambda.max). The presence / absence of strain hardening is determined by whether or not there is an inflection point at which the extensional viscosity changes from an upward convex curve to a downward convex curve over time.
1 and 2 are typical plots of elongational viscosity. FIG. 1 shows a case where an inflection point of elongational viscosity is observed, and η _Max (t1) and η _Linear (t1) are shown in the figure. FIG. 2 shows a case where an inflection point of elongational viscosity is not observed.

Since the flame retardant resin composition of the present invention is a polyethylene resin composition having the above characteristics (1) to (3), the pellets are decomposed and foamed while the hollow moldability is good. It can be molded without causing it to occur, and it is possible to obtain a flame retardant resin composition having excellent flame retardancy and excellent impact resistance.
Furthermore, preferably, in addition to the above characteristics (1) to (3), the flame retardant resin composition having one or more of the above characteristics (4) to (7) exhibits the above-described effects better. Become.

  The flame-retardant resin composition of the present invention can form a pellet without causing phenomena such as decomposition and foaming while having good hollow moldability, and is excellent in flame retardancy and impact resistance. Since it is an excellent flame retardant resin composition, it is suitably used as a flame retardant resin composition for hollow molding, and in particular, flame retardant for hollow molding used in containers and building materials that require flame resistance. It is suitably used as a conductive resin composition.

5. Method for Producing Flame Retardant Resin Composition The flame retardant resin composition of the present invention is obtained by melting and mixing the (A) ethylene polymer and the (B) flame retardant at a predetermined blending ratio. Accordingly, it can be produced by adding other components and melt-mixing them.

The method for producing a flame retardant resin composition of the present invention includes a step of mixing the (A) ethylene polymer and the (B) flame retardant at a temperature of the resin composition of 185 ° C. or higher and 208 ° C. or lower. It is preferable from the viewpoint that pellets can be easily formed without causing phenomena such as decomposition of the flame retardant and foaming.
When the temperature of the resin composition is higher than the above upper limit and the (A) ethylene polymer and the (B) flame retardant are mixed, the flame retardant tends to be easily decomposed or foamed. is there. When such a phenomenon such as decomposition or foaming of the flame retardant occurs, the flame retardant resin composition tends to fail to satisfy the characteristics (2) and (3).

  Moreover, it is preferable that the manufacturing method of the flame-retardant resin composition of this invention has the drying process of a pellet further. Pellets containing a large amount of flame retardant are likely to absorb water and may easily foam during molding.

The flame retardant resin composition of the present invention is a conventional method, for example, a blend of resin, flame retardant, additive and the like is uniformly mixed using a tumbler, Henschel mixer, etc., and a roll, Banbury mixer, Conida, uniaxial After pelletizing by mechanical melt mixing with an extruder, a twin screw extruder, etc., it can be molded by various molding machines to obtain a desired molded product.
In any production method, the above-described composition of the present invention can provide a molding material having excellent hollow moldability, but a molding material having a good kneading state and less flame retardant decomposition during melt kneading can be obtained. A production method using a roll, Banbury, Conida, or twin screw extruder is desirable.
In addition, the polyethylene resin composition obtained by the above-mentioned method is not limited to other olefinic polymers and rubbers, but also dispersants, lubricants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, etc. Known additives such as an agent, an antifogging agent, an antiblocking agent, a processing aid, a color pigment, a crosslinking agent, a foaming agent, and a reinforcing material can be blended.
In any case, the polyethylene resin composition can be blended with various additives as necessary and kneaded with a kneading extruder, a Banbury mixer, or the like to obtain a molding material.

6). Flame-retardant resin composition pellets The flame-retardant resin composition pellets of the present invention are flame-retardant resin composition pellets obtained by melt-extruding the flame-retardant resin composition of the present invention.
The flame-retardant resin composition pellet of the present invention is a preferred embodiment of the flame-retardant resin composition of the present invention, and satisfies the above characteristics (1) to (3).

In addition, since the flame retardant resin composition pellets of the present invention are produced without causing phenomena such as decomposition and foaming during production, the inclusion of voids in the pellets is suppressed. is there.
In the case of pellets that cause phenomena such as decomposition and foaming during production and contain voids, it becomes difficult to satisfy the above characteristics (1) to (3), and it is difficult to obtain good hollow moldability. is there.

  The flame-retardant resin composition pellets of the present invention are produced, for example, by directly cutting the resin composition extruded from an extruder into pellets, or forming the strands and then cutting the strands with a pelletizer. The Moreover, although the shape of a pellet can take common shapes, such as a cylinder, a prism, and a spherical shape, it is a cylinder more suitably. The diameter of such a cylinder is preferably 1 mm to 10 mm, more preferably 1.5 mm to 7 mm, and still more preferably 2 mm to 5 mm. On the other hand, the length of the cylinder is preferably 1 mm to 5 mm, more preferably 1.5 mm to 4 mm, and still more preferably 2 mm to 3 mm.

7). Molded product and hollow molded product The molded product of the present invention is a molded product containing the flame-retardant resin composition according to the present invention.
Moreover, the hollow molded article of the present invention is a hollow molded article containing the flame retardant resin composition according to the present invention.
The molded article of the present invention can be produced by various molding methods using the flame retardant resin composition of the present invention as a raw material. Since the flame-retardant resin composition of the present invention has good hollow moldability, the molded product of the present invention is preferably a hollow molded product mainly molded by a hollow molding method or the like.

The hollow molded article of the present invention can be obtained by hollow molding using a known hollow molding machine from the flame retardant resin composition of the present invention.
The molding conditions for hollow molding may be appropriately selected according to the hollow molded product to be obtained. For example, the molding temperature is preferably 160 ° C to 220 ° C.

Since the flame-retardant resin composition of the present invention has good hollow moldability, excellent flame retardancy, and excellent impact resistance, the molded article or hollow molded article of the present invention using the flame-retardant resin composition is flame retardant. Excellent in impact resistance.
Therefore, it is suitably used for building materials, machine parts, automobile parts, various resin trays and containers that require such characteristics, and more specifically, for example, chairs of stadiums, stadiums, gymnasiums, etc. , Temporary toilets, battery cases, construction machinery, agricultural machinery roofs, bonnets, automotive bumpers, engine covers, fenders, exterior panels, pipes, ducts, kerosene tanks, agricultural machinery tanks, medical tanks, various containers, etc. It can be used suitably.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

1. Measurement method The measurement methods used in the examples are as follows.
(1) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg:
Measured according to JIS K6922-2: 1997.
(2) Density:
It was measured by the D method according to JIS K7112: 1999.

(3) Measurement of molecular weight and molecular weight distribution by gel permeation chromatography (GPC):
It measured by the gel permeation chromatography (GPC) of the following conditions.
[Measurement condition]
Model used: Alliance GPCV2000 manufactured by Japan Waters Co., Ltd. Measurement temperature: 145 ° C
Solvent: orthodichlorobenzene (ODCB)
Column: Showex Denko Shodex HT-806M x 2 + HT-G
Flow rate: 1.0 mL / min Injection rate: 0.3 mL
[Sample preparation]
A 3 mL sample and 3 mL of orthodichlorobenzene (containing 0.1 mg / mL 1,2,4-trimethylphenol) were weighed into a 4 mL vial, and capped with a resin screw cap and a Teflon (registered trademark) septum. Then, it melt | dissolved for 2 hours using the SSC-9300 type | mold high temperature shaker by Senshu Scientific set to the temperature of 150 degreeC. After dissolution, it was visually confirmed that there were no insoluble components.
[Create calibration curve]
Four 4 mL glass bottles are prepared, and 0.2 mg each of monodisperse polystyrene standard samples or n-alkanes of the combinations (1) to (4) below are weighed, followed by orthodichlorobenzene (0.1 mg / mL). Of SSC-9300 model manufactured by Senshu Kagaku, which was set at a temperature of 150 ° C. after weighing 3 mL (including 1,2,4-trimethylphenol) and capping with a resin screw cap and a Teflon (registered trademark) septum. Dissolution was carried out for 2 hours using a shaker.
(1) Shodex S-1460, S-66.0, n-eicosane (2) Shodex S-1950, S-152, n-tetracontane (3) Shodex S-3900, S-565, S -5.05
(4) Shodex S-7500, S-1010, S-28.5
The vial containing the sample solution was set in the apparatus, measured under the above-mentioned conditions, and a chromatogram (retention data and differential refractometer detector response data set) was recorded at a sampling interval of 1 s. The retention time (peak apex) of each polystyrene standard sample was read from the obtained chromatogram and plotted against the logarithmic value of molecular weight. Here, the molecular weights of n-eicosane and n-tetracontane were 600 and 1200, respectively. A nonlinear least square method was applied to this plot, and the obtained quartic curve was used as a calibration curve.
[Calculation of molecular weight]
Measurement was performed under the above-mentioned conditions, and a chromatogram was recorded at a sampling interval of 1 s. this
Chromatogram Sadao Mori “Size Exclusion Chromatography” (Kyoritsu Shuppan) Chapter 4 p. The differential molecular weight distribution curve and average molecular weight values (Mn, Mw and Mz) were calculated by the method described in 51-60. However, in order to correct the molecular weight dependency of dn / dc, the height H from the baseline in the chromatogram was corrected by the following equation. Chromatogram recording (data acquisition) and average molecular weight calculation were performed on a PC on which Microsoft Windows OS (registered trademark) XP was installed by using a program (manufactured by Microsoft Visual Basic 6.0 manufactured by Microsoft).
H ′ = H / [1.032 + 189.2 / M (PE)]
In addition, the following formula was used for the molecular weight conversion from polystyrene to polyethylene.
M (PE) = 0.468 × M (PS)

(4) Melt tension:
The melt tension (MT) was determined by measuring the stress when the melted ethylene polymer or resin composition was stretched at a constant speed, and was measured under the following conditions.
[Measurement condition]
Model used: Toyo Seiki Seisakusho, Capillograph 1B
Nozzle diameter: 2.095mm
Nozzle length: 8.0mm
Inflow angle: 180 ° (flat)
Extrusion speed: 15 mm / min Take-off speed: 6.5 m / min Measuring temperature: 190 ° C.

(5) Melting point (Tm):
The melting point was measured with a differential scanning calorimeter (DSC). About 5 mg of a 0.2 mm thick press sheet cut into a circle is packed in an aluminum pan, heated to 200 ° C. in a nitrogen atmosphere, held at the same temperature for 5 minutes, and up to 30 ° C. at 10 ° C./min. After cooling and holding at the same temperature for 5 minutes, the temperature was raised to 200 ° C. at 10 ° C./min, and the temperature at which the change in the amount of heat accompanying melting was maximized was determined as the melting point (Tm).

(6) Degree of strain hardening (λmax):
Using a test piece prepared by press forming a sheet of 18 mm × 10 mm and thickness 0.7 mm, using a rheometer (Ales manufactured by Rheometrics), measurement of elongational viscosity at 170 ° C. and strain rate of 0.1 / second is performed. The presence or absence of a long-chain branched structure was confirmed by the presence or absence of an inflection point of elongational viscosity resulting from strain hardening.
[Measurement condition]
Apparatus: Ales manufactured by Rheometrics
Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
[Calculation method]
The elongational viscosity at 170 ° C. and strain rate of 0.1 / second was plotted on a logarithmic graph with time t (unit: second) on the horizontal axis and elongation viscosity η (t) (unit: Pa · second) on the vertical axis. On the log-log graph, the maximum elongation viscosity until strain becomes 4.0 after strain hardening is η _Max (t1) (t1 is the time when the maximum elongation viscosity is shown), and the extension viscosity before strain hardening. when the approximate line was η _linear (t), defines the value calculated as _{η Max (t1) / η linear} (t1) strain hardening degree and (.lambda.max). The presence or absence of strain hardening is determined depending on whether or not the extension viscosity has an inflection point that changes from an upward convex curve to a downward convex curve over time. ○, the case where it does not have was marked as x.

(7) Tensile fracture strength:
In accordance with JIS K6922-2: 2010, a sheet with a thickness of 4 mm is prepared by compression molding, a multipurpose test piece 1B is prepared, and measurement is performed at 23 ° C. and 50% RH at a tensile speed of 50 mm / min. did.

(8) Charpy impact strength:
In accordance with JIS K7111: 2004, a type 1 test piece is prepared, the striking direction is edgewise, the notch type is type A (0.25 mm), and measurement can be performed at 23 ° C. and 50% RH. .

(9) Flame retardancy:
In accordance with JIS K6922-2: 2010, a test piece for flame retardancy evaluation was molded by compression molding, and the flame retardancy was evaluated according to the UL94-V standard (thickness 3 mmt).
The combustion rank was given according to UL94-V specification. V-0 has the highest combustion rank, and the flame retardance decreases as V-1 and V-2.

(10) Foaming state of pellet The amount of bubbles contained in the pellet was evaluated by visual observation.
○: No firing was confirmed visually.
X: Firing is confirmed visually.

2. Examples and Comparative Examples [Production of Resin Composition]
[Example 1]
Using a twin screw extruder, ethylene polymer (A-1) 51 kg / h, flame retardant (B-1) 12 kg / h, total of 100 (A) ethylene polymer and (B) flame retardant Feed with 0.1 parts by mass of antioxidant (C-1) added and mixed with respect to parts by mass, and further add 12 kg / h of flame retardant (B-1) to the segment after melting using a side feeder The mixture was fed and kneaded at a resin temperature of 191 ° C. to obtain a flame retardant resin composition. Table 1 shows the evaluation results of the properties of the flame retardant resin composition.
In addition, as an ethylene-type polymer (A-1), the Nippon Polyethylene make and Novatec HB235R were used. The characteristics of the ethylene polymer (A-1) are shown in Table 1.
Moreover, as a flame retardant (B-1), the product of ADEKA, ADEKA STAB FP-2200 (diamine amine pyrophosphate component / piperazine pyrophosphate component = about 40/60 (mass ratio) containing an amine phosphate salt; -164217) was used.
Further, as the antioxidant (C-1), a hindered phenol antioxidant IRGANOX1010 manufactured by BASF Corporation was used.

[Examples 2 to 5]
A flame retardant resin composition was produced in the same manner as in Example 1 except that the conditions were set to be the compositions shown in Table 1 and the resin temperature and resin treatment amount during kneading were changed as shown in Table 1. . Table 1 shows the physical properties and evaluation results of the obtained flame-retardant resin composition.

[Example 6]
Using a twin screw extruder, ethylene polymer (A-1) 138 kg / h, flame retardant (B-1) 8 kg / h, and (A) ethylene polymer and (B) flame retardant To 100 parts by mass in total, 0.1 parts by mass of antioxidant (C-1) was added and mixed, and kneaded at a resin temperature of 194 ° C. to obtain a flame retardant resin composition. Table 1 shows the evaluation results of the properties of the flame retardant resin composition.

[Examples 7 to 8]
A flame retardant resin composition was produced in the same manner as in Example 6 except that the conditions were set to be the compositions shown in Table 1 and the resin temperature and resin treatment amount during kneading were changed as shown in Table 1. . Table 1 shows the physical properties and evaluation results of the obtained flame-retardant resin composition.
As the lubricant (C-2), RIKENMASTER EXR-060 (containing metal soap) manufactured by Riken Vitamin Co., Ltd. was used.
Further, as the dispersant (C-3), Denon 1147 (containing nonionic surfactant) manufactured by Maruhishi Oil Chemical Co., Ltd. was used.

[Comparative Example 1]
A flame retardant resin composition was produced in the same manner as in Example 1 except that the conditions were set to be the compositions shown in Table 1 and the resin temperature and resin treatment amount during kneading were changed as shown in Table 1. . Table 1 shows the physical properties and evaluation results of the obtained flame-retardant resin composition.

[Comparative Examples 2-3]
A flame retardant resin composition was produced in the same manner as in Example 6 except that the conditions were set to be the compositions shown in Table 1 and the resin temperature and resin treatment amount during kneading were changed as shown in Table 1. . Table 1 shows the physical properties and evaluation results of the obtained flame-retardant resin composition.
In addition, as an ethylene-type polymer (A-2), the Nippon Polyethylene company make and Novatec HB216R were used. The characteristics of the ethylene polymer (A-2) are shown in Table 1.
The flame retardant resin compositions of Comparative Examples 1 and 2 generated heat during kneading of (A) the ethylene polymer and (B) the flame retardant, and foamed during pellet molding. When molding using pellets fired in this way, a parison is formed in which bubbles are taken in at the time of molding, and at the time of blow-up, poor appearance due to bursting of bubbles, and holes in the molded product will open, A good molded product could not be obtained.
In the flame-retardant resin composition of Comparative Example 3, the MFR of the ethylene polymer (A-2) is smaller than the specific range of the ethylene polymer used in the present invention, and (B) generates heat when kneaded with the flame retardant. Then, it foamed during pellet molding. When molding using the pellets fired in this way, a parison in which bubbles are taken in at the time of molding is formed, and at the time of blow-up, bad appearance due to bursting of bubbles and holes in the molded product will be opened A good molded product could not be obtained.

表中、「Ｎ．Ａ．」とは、発泡が顕著で測定できなかったことを示す。
表中、「Ｎ．Ｂ．」とは、試験片が破壊しなかったことを示す。

In the table, “NA” indicates that foaming was remarkable and could not be measured.
In the table, “NB” indicates that the test piece did not break.

  The significance and rationality of the configuration of the present disclosure and the superiority with respect to the prior art are clarified by the good results of the above examples and the comparison with the comparative examples.

  According to the present invention, while the hollow moldability is good, the pellets can be molded without causing phenomena such as decomposition and foaming, and have excellent flame resistance and impact resistance. Since it is possible to provide a molded product and a hollow molded product excellent in flame retardancy and impact resistance containing the flame retardant resin composition, production method thereof, pellets thereof, and the flame retardant resin composition, Very useful.

Claims (10)

(A) An ethylene polymer that is at least one of an ethylene homopolymer and an ethylene-α-olefin copolymer and satisfies the following characteristics (i) to (ii); and (B) an organic flame retardant It contains a non-halogen flame retardant, and (B) the flame retardant is 5 parts by mass or more and 44 parts by mass or less with respect to a total of 100 parts by mass of the (A) ethylene polymer and the (B) flame retardant. A flame retardant resin composition satisfying the following characteristics (1) to (3).
Characteristic (i) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (ii) The density is 0.940 g / cm ³ or more and 0.970 g / cm ³ or less.
Characteristic (1) The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and 1.0 g / 10 min or less.
Characteristic (2) The tensile fracture strength measured according to JIS K6922-2: 2010 is 10 MPa or more and 30 MPa or less.
Characteristics (3) JIS K7111: Charpy impact strength measured according to 2004 is 2.0 kJ / ^{m 2} or more 10 kJ / ^{m 2} or less. The flame-retardant resin composition according to claim 1, which satisfies the following property (4).
Characteristic (4) The melt tension (MT) measured at 190 ° C. is 40 mN or more.   The flame retardant resin composition according to claim 1 or 2, wherein the organic flame retardant comprises a phosphate compound.   The phosphate compound is at least one compound selected from the group consisting of melamine orthophosphate, melamine pyrophosphate, melamine polyphosphate, piperazine orthophosphate, piperazine pyrophosphate, and piperazine polyphosphate. The flame-retardant resin composition according to claim 3.   Furthermore, the flame-retardant resin composition as described in any one of Claims 1-4 containing a metal soap.   The flame-retardant resin composition according to any one of claims 1 to 5, which is for hollow molding.   The temperature of a resin composition is 185 degreeC or more and 208 degrees C or less, Said (A) ethylene polymer and said (B) flame retardant are mixed, The any one of Claims 1-6 characterized by the above-mentioned. A method for producing a flame retardant resin composition.   The flame-retardant resin composition pellet formed by melt-extruding the flame-retardant resin composition as described in any one of Claims 1-6.   The molded article containing the flame-retardant resin composition as described in any one of Claims 1-6.   The hollow molded article containing the flame-retardant resin composition as described in any one of Claims 1-6.

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