JP2001064448A - Polyethylene powder and powder molded product produced by using the powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain polyethylene powder having a specific property, excellent flowability and handleability, etc., and suitable for powder molding by including respectively specific amounts of an ethylene-α-olefin copolymer produced by using a specific metallocene catalyst, a specific polyethylene and an elastomer. SOLUTION: The objective powder having a bulk density of 0.20-0.50 g/cm3 contains (A) 100 pts.wt. of an ethylene-α-olefin copolymer having a density of 0.880-0.960 g/cm3 and a melt flow rate(MFR) of 0.1-200/10 min and produced by using a metallocene catalyst, (B) 0-300 pts.wt. of a high-pressure-produced low-density polyethylene having a density of 0.900-0.940 g/cm3 and an MFR of 0.1-100/10 min and (C) 1-50 pts.wt. of an elastomer (e.g. polystyrene- polybutadiene block copolymer).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyethylene powder suitable for powder molding and a powder molded product using the same. Specifically, it is suitable for the production of powder molded products,
Excellent powder fluidity, handleability, excellent film appearance, excellent impact resistance, excellent chemical resistance, mechanical properties such as tensile strength, constant strain environmental stress cracking (ESCR), adhesion The present invention relates to a polyethylene powder containing polyethylene and an elastomer produced by an excellent metallocene catalyst, and a powder molded product using the same.

[0002]

2. Description of the Related Art As an adhesive resin powder using a metallocene-based polyethylene and a rubber component, Japanese Patent Application Laid-Open No.
No. 24 discloses that (A) ethylene (co) having specific properties
A composition (A + B) comprising at least 20% by weight of a polymer, at most 80% by weight of a polyolefin resin other than the ethylene (co) polymer (B) and the component (A), and at most 30% by weight of a rubber (C).
+ C = 100% by weight), wherein at least one of the component (A), the component (B) and the component (C) in the composition is graft-modified with at least one of the above-mentioned monomers for graft modification, and the graft monomer An adhesive resin powder comprising a composition in an amount of 10 ^-8 to 10 ^-3 mol per 1 g of the composition is disclosed.

[0003] JP-A-9-176522 discloses (A)
(A) ethylene or ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a catalyst containing a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton (co) Obtained by polymerizing,
(B) a density of 0.86 to 0.97 g / cm ³ , (c) a melt flow rate of 0.01 to 100 g / 10 minutes,
(D) molecular weight distribution Mw / Mn of 1.5 to 5.0, (e)
20% by weight or more of an ethylene (co) polymer having a composition distribution parameter Cb of 1.2 or less, 80% by weight or less of a polyolefin resin other than the ethylene (co) polymer of the component (B) and (A), and (C) rubber Composition comprising 30% by weight or less (A
+ B + C = 100% by weight), and at least one of the component (A), the component (B) and the component (C) in the composition contains a carboxylic acid group, an acid anhydride group, an ester group, a hydroxyl group, an amino group and Graft-modified with at least one monomer containing a functional group selected from silane groups,
And the amount of the graft monomer is 10 g / g of the resin component.
An adhesive resin powder comprising a composition having ^-8 to 10 ^-3 mol is disclosed.

[0004]

DISCLOSURE OF THE INVENTION The present invention is suitable for powder molding, in particular, has excellent mechanical properties such as tensile strength, excellent constant strain environmental stress cracking (ESCR), and excellent chemical resistance. A polyethylene powder containing a polyethylene composition mainly composed of an ethylene-α-olefin copolymer and an elastomer produced from a metallocene catalyst having excellent adhesive strength, good fluidity, and excellent film appearance, and using the same. An object is to provide a powder molded product.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an ethylene-α-catalyst prepared from a metallocene catalyst having the following characteristic (A).
100 parts by weight of olefin copolymer, 0 to 30 parts by weight of high-pressure low-density polyethylene having the following property (B), and (C)
The present invention relates to a polyethylene powder having the following property (D) comprising a polyethylene composition containing 1 to 50 parts by weight of an elastomer. (A) Ethylene-α-olefin copolymer produced from a metallocene catalyst (A1) Density: 0.880 to 0.960 g / cm ³ (A2) Melt flow rate (MFR): 0.1 to 20
0 g / 10 min (B) High pressure method low density polyethylene (B1) Density: 0.900 to 0.940 g / cm ³ (B2) Melt flow rate (MFR): 0.1 to 10
0 g / 10 min (D) Polyethylene powder (D1) Bulk density: 0.20 to 0.50 (g / cm ³ )

Further, the present invention relates to a powder molded product using the polyethylene powder of the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An ethylene-α-olefin copolymer produced from the metallocene catalyst (A), a high-pressure low-density polyethylene (B), and (C) are included in the present invention.
The elastomer and other resin components contained in the powdered polyethylene powder of the present invention include at least a carboxylic acid group, an acid anhydride group, an ester group, a hydroxyl group, a functional group selected from an amino group and a silane group. It is a type of monomer that is not graft-modified.

[0008] The polyethylene powder of the present invention comprises ethylene-α- produced from a metallocene catalyst having the following characteristic (A).
100 parts by weight of an olefin copolymer, 0, preferably 0.1 part by weight of a high-pressure low-density polyethylene having the following property (B):
More preferably 0.5 parts by weight, particularly preferably 3 to 30 parts by weight, preferably 25 parts by weight, more preferably 20 parts by weight, particularly preferably 10 parts by weight, and (C) 1 part by weight of elastomer. Polyethylene, preferably 2 parts by weight, more preferably 3 parts by weight, particularly preferably 5 to 50 parts by weight, preferably 40 parts by weight, more preferably 30 parts by weight, particularly preferably 15 parts by weight. A polyethylene powder comprising the composition and having the following property (D). (A) Ethylene-α-olefin copolymer produced from a metallocene catalyst (A1) Density: 0.880 g / cm ³ , preferably 0.1%
905 g / cm ³ , more preferably 0.925 g / c
m ³ , particularly preferably from 0.930 g / cm ³ to 0.96
0 g / cm ^3, preferably 0.955 g / cm ^3, more preferably 0.950 g / cm ^3, particularly preferably 0.
Range of 945g / cm ³ (A2) melt flow rate (MFR): 0.1g / 1
0 min, preferably 0.5 g / 10 min, more preferably 1 g / 10 min, particularly preferably 2 g / 10 min to 200
g / 10 min, preferably 20 g / 10 min, more preferably 10 g / 10 min, particularly preferably 5 g / 10 min. (B) High-pressure low-density polyethylene (B1) Density: 0.900 g / cm ³ , preferably Is 0.
915 g / cm ³ , more preferably 0.920 g / c
m ³ , particularly preferably 0.923 g / cm ³ to 0.94
0 g / cm ^3, preferably 0.937 g / cm ^3, more preferably 0.935 g / cm ^3, particularly preferably 0.
Range of 933 g / cm ³ (B2) Melt flow rate (MFR): 0.1 g / 1
0 min, preferably 0.2 g / 10 min, more preferably 0.3 g / 10 min, particularly preferably 0.5 g / 10 min to 200 g / 10 min, preferably 20 g / 10 min, more preferably 10 g / 10 min. And particularly preferably 5 g / 1.
(D) Polyethylene powder for powder molding (D1) Bulk density: 0.20 (g / cm ³ ), preferably 0.30 (g / cm ³ ), more preferably 0.32
(G / cm ³ ), particularly preferably 0.35 (g / cm ³ )
To 0.50 (g / cm ³ ), preferably 0.48 (g
/ Cm ³ ), more preferably 0.45 (g / cm ³ ),
Particularly preferably, it is in the range of 0.43 (g / cm ³ ).

Ethylene prepared from a metallocene catalyst
The α-olefin copolymer preferably further has at least one or more of the following properties. (A) Ethylene-α-olefin copolymer produced from a metallocene catalyst (A3) Melt flow rate (MFR _10.0 ) at 190 ° C, 10.0 kg load and melt flow rate (MFR _2.16 ) at 190 ° C, _2.16 kg load ) And ratio
(MFR _10.0 ) / (MFR _2.16 ) is 3, preferably 4,
(A4) Molecular weight distribution (Mw / Mn) is 2.0, preferably 2.2, more preferably 2.4, more preferably 5 to 10, preferably 9, more preferably 8, and particularly preferably 7. Particularly preferably in the range of 2.6 to 4.0, preferably 3.7, more preferably 3.5, particularly preferably 3.4. (A5) The swell ratio (SR) at 190 ° C. is (S5)
R) <1.35, preferably (SR) ≦ 1.25, particularly preferably (SR) ≦ 1.20

The polyethylene powder for powder molding preferably further has at least one or more of the following characteristics. (D) Polyethylene powder for powder molding (D2) Flow angle of repose is 30 °, more preferably 33 °, especially 37
(D3) The average particle diameter is 100 μm, further 130 μm,
In particular, in the range of 150 μm to 300 μm, more preferably 270 μm, especially 250 μm. (D4) Uniformity is 1.5, further 1.6, especially 1.7
In the range from 2.5 to 2.3, especially 2.3

[0011] Of the above properties, if the (A1) density is smaller than the above range, the film of the powder molded product is easily damaged, and its commercial value is reduced.

(A2) If MFR _2.16 is less than the above range, the fluidity is poor and powder molding becomes difficult. On the other hand, if it is larger than the above range, the mechanical properties of the obtained film are deteriorated.

(D1) If the bulk density is outside the above range, the fluidity of the powder is poor and the powder molding becomes difficult.

When (A3) (MFR _10.0 ) / (MFR _2.16 ) is larger than the above range, the thickness of the film of the powder molded article may vary greatly, which is not preferable. (A4) If the molecular weight distribution (Mw / Mn) is larger than the above range, the thickness of the film of the powder molded product may vary greatly, which is not preferable. (A5) If the swell ratio (SR) is larger than the above range, the variation in the thickness of the film of the powder molded article becomes large,
In addition, the surface smoothness may decrease, which is not preferable.

Of the above properties, (D2) if the flow angle of repose is out of the above range, the flowability of the powder is poor and the powder molding may be difficult, which is not preferable. (D3) When the average particle size is out of the above range, the fluidity of the powder is deteriorated, the unmelted portion remains in the film of the powder molded product, the product appearance is deteriorated, and the surface smoothness is reduced. Is not preferred. (D4) If the degree of uniformity is out of the above range, the fluidity of the powder is poor and powder molding may be difficult, which is not preferable.

Ethylene prepared from a metallocene catalyst
The α-olefin copolymer (A) can be produced by a known polymerization method using a metallocene catalyst, for example, a gas phase polymerization reaction, a liquid phase polymerization reaction, or the like. An ethylene-α-olefin copolymer produced from a metallocene catalyst produced from a gas phase polymerization reaction can be used.

As the metallocene catalyst, a known metallocene catalyst can be used. For example, as the metallocene-based catalyst, a combination of a metallocene compound of a transition metal of Group IV or V of the periodic table, an organic aluminum compound and / or an ionic compound can be used.

The transition metals of Groups IV or V of the Periodic Table include:
Titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V) and the like are preferable.

The ethylene-α-olefin copolymer contains ethylene as a main component and has 2 to 8 carbon atoms such as propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1 and octene-1. And α-olefins such as cyclic α-olefins such as cyclopentene and cyclohexene, or a mixture thereof and a copolymer produced from a metallocene catalyst. 50% by mole or more of ethylene, 60% by weight
An ethylene-α-olefin copolymer of an olefin having 3 to 8 carbon atoms in an amount of at least 70 mol%, particularly at least 70 mol%, can be preferably used. In particular, the content of the repeating unit derived from the α-olefin in the copolymer of ethylene and α-olefin is usually 10 mol% or less, and more preferably 0.1 mol% or less.
The ethylene-α-olefin copolymer contained in the range of 1 to 9 mol%, particularly in the range of 0.1 to 4 mol% is preferable.

The high-pressure low-density polyethylene (B) can be produced by high-pressure radical polymerization.

As the high-pressure low-density polyethylene (B), not only a homopolymer of ethylene but also a copolymer with another monomer such as an ethylene-vinyl acetate copolymer can be used. When an ethylene-vinyl acetate copolymer is used, the amount of the repeating unit derived from vinyl acetate in the copolymer is usually preferably 20% by weight or less.

As the elastomer, rubber components such as butadiene rubber, isoprene rubber and butyl rubber, polystyrene / polybutadiene block copolymer, polystyrene / polystyrene
Polyisoprene block copolymer, polystyrene / polybutadiene / polystyrene block copolymer (SB
S), polystyrene / polyisoprene / polystyrene block copolymer (SIS), polystyrene / polyethylene / butylene / polystyrene block copolymer (SEB)
S), styrene-based thermoplastic elastomers such as polystyrene / polyethylene / propylene / polystyrene block copolymer (SEPS) can be used. As elastomers, polystyrene / polybutadiene block copolymer, polystyrene / polyisoprene block copolymer, polystyrene / polybutadiene / polystyrene block copolymer (SBS), polystyrene / polyisoprene / polystyrene block copolymer (SIS), polystyrene / polyethylene / Butylene / polystyrene block copolymer (SEBS), polystyrene / polyethylene / propylene / polystyrene block copolymer (SEBS)
Styrenic thermoplastic elastomers such as PS) are preferred.

The polyethylene composition of the present invention may contain, depending on the intended use, ethylene-α-produced from a metallocene catalyst.
Polyolefin-based polymers, such as high-density polyethylene, excluding olefin copolymers, high-pressure low-density polyethylene, and elastomers can be added.

The polyethylene powder of the present invention can be produced by a method of pulverizing the above polyethylene composition using a pulverizer, for example, a high-speed rotary pulverizer, a method of improving the powder shape by post-treatment, or the like. preferable. In particular, polyethylene powder for powder molding produced by a method of pulverizing using a high-speed rotary pulverizer at room temperature and classifying with a vibrating sieve has good powder flowability, The product has excellent surface smoothness.

The polyethylene powder or polyethylene composition of the present invention may contain a lubricant, an antiblocking agent, an antioxidant, an ultraviolet absorber, a flame retardant, an inorganic or organic filler, a pigment, an antistatic agent, etc. Can be added.

The polyethylene powder of the present invention can be suitably used for a powder molding method. As a powder molding method, a rotational molding method, a fluid immersion method, a probe back method, a fusion coating method and the like are preferable.

The polyethylene powder of the present invention can be produced by a powder molding method by using tanks for transporting and storing liquids, gases, and solids such as chemicals and drinking water, toys such as chairs, slides, carts, and the like.
Containers such as lorry containers, tool boxes, boxes, flower stands, appreciation ponds, household waste such as garbage disposal, and other molded products can be manufactured.

The polyethylene powder of the present invention is suitable for powdered polyethylene-lined steel pipes which can be widely used in the fields of chemicals, seawater, water and sewage, and gas pipelines, which impart a corrosion-resistant function to steel pipes by a powder molding method. Can be used.

The polyethylene powder of the present invention and a powder molded product using the same preferably have a constant strain environmental stress cracking time (ESCR) of 800 hours or more, more preferably 900 hours or more, particularly more than 1000 hours. Having the constant-strain environmental stress cracking time is preferable because it has excellent crack resistance, which is a risk of being generated in an environmental atmosphere in which the obtained powder molded product is placed.

The polyethylene powder of the present invention has a chemical resistance of 17.5 wt% or less when immersed in gasoline.
A powder molded product of 3 wt% or less, particularly 17.1 wt% or less can be obtained.

The polyethylene powder of the present invention has a tensile strength of 22 MPa or more, more preferably 22.5 MPa or more, especially 23 MPa or more.
A powder molded product having a pressure of not less than MPa can be obtained.

With the polyethylene powder of the present invention, a powder molded product having an adhesive strength of 100 N / 10 mm or more, more preferably 103 N / 10 mm or more, especially 107 N / 10 mm or more can be obtained.

[0033]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The characteristic values were measured as follows. -Method for measuring properties of polyethylene [1] Density (g / cm ³ ): MFR under a load of 2.16 kg at 190 ° C. according to JIS K7112.
The strand obtained at the time of the measurement was heat-treated at 100 ° C. for 1 hour, and the sample which was gradually cooled to room temperature over 1 hour was measured using a density gradient tube. [2] Melt flow rate (MFR _2.16 ) (g / 10m)
in): In accordance with JIS K7210, the weight was determined by measuring the weight of the resin extruded into a strand in 10 minutes under a load of 2.16 Kg at 190 ° C. using a melt indexer. [3] Melt flow rate ratio (MFR _10.0 ) / (MFR
_2.16 ): A value obtained by dividing MFR _10.0 obtained by _10.0 kg load by MFR _2.16 in the same manner as in the above method [2].

[4] Molecular weight distribution: The molecular weight distribution (Mw / Mn) of the polyethylene composition was measured by gel permeation chromatography (GPC). The measurement method is shown below. (1) Measuring device: WATERS 150CV was used. (2) Measurement sample: polyethylene composition at a temperature of 14
It was dissolved in a solvent (o-dichlorobenzene) at 5 ° C at a concentration of 1 mg / ml. (3) Measurement of molecular weight distribution: Measurement sample of (2) above.
4 ml was injected into two GPC columns AT-806MS, and the solvent was o-dichlorobenzene at a temperature of 145 ° C. and 1.0 g.
Performed at a flow rate of ml / min. The measurement by GPC was performed for 35 minutes. The polymer concentration in the solution separated by the GPC column was measured with a differential refractometer (RI). The molecular weight is
It was converted by a polystyrene standard. (4) Data processing: Data processing is performed in VAX-STATI
ON3100 was used. G obtained by the above measurement (3)
When a baseline is drawn on the PC chromatogram, the area is integrated using data processing software attached to the apparatus, and the number average molecular weight (Mn), weight average molecular weight (Mw), Mw / Mn
Is automatically calculated. The GPC chromatogram is defined on the screen of the apparatus as the size of the figure, with the horizontal axis standardizing 125 mm per 20 minutes of measurement time and the vertical axis the total integrated elution amount as 100,
The measurement was performed at 13 mm per 20 mm.

[5] Swell ratio: Using an orifice having a temperature of 190 ° C., a diameter of 2.09 mmφ, and a length of 8 mm (with a taper), 10 mm /
The diameter (Ds) of the molten strand 7 mm below the nozzle when the resin was extruded at a speed of min was measured with a laser and divided by the orifice diameter (Do) (Ds / Do).

Method for measuring properties of polyethylene powder [1] Bulk density (g / cm 3): Measured according to JIS K6721. [2] Flow angle of repose (°): This was performed using a three-wheeled flow surface angle measuring instrument manufactured by Tsutsui Physical and Chemical Machinery. The measurement is (1) 500
After about 200 cm ³ of the sample powder was placed in a cylindrical measurement bottle of 200 ml, the bottle was capped. (2) Place the measuring bottle containing the powder prepared in (1) on the trolley of the three-wheeled flow surface angle measuring instrument, and rotate it at a rotation speed of 3 rpm. The flow angle of repose of the sample powder in the measuring bottle was measured. [3] Medium particle size (μm): 50 g of the powder was treated with a low tap sieve shaker at 300 rpm and 162 strokes / min for 10 minutes. The sieve used was 45, 50, 6
0, 70, 80, 100, 120, 140, 170, 2
Eleven types of 00 and 230 mesh were used. The weight of the powder remaining on each sieve was measured, and the sieve having a small particle size (23
0 mesh) to a large sieve (45 mesh)
Integrate the weight of powder remaining on the sieve from the smaller sieve side,
The integral value for each sieve was determined. The integrated value was divided by the total weight of the powder and multiplied by 100 to determine the cumulative weight (%). The opening (μm) of each sieve was plotted on the horizontal axis, and the cumulative weight (%) was plotted on the vertical axis, and a curve of the opening and the cumulative weight (%) was drawn. From this curve, the aperture value at a cumulative weight of 50% was determined, and this value was taken as the median particle size.

[4] Uniformity: On the curve obtained by the measurement in the above [3], the opening value with the cumulative weight of 60% and 10% was determined, and this value was calculated as the 60% particle size under the sieve and 10%. The particle size under the sieve was used.
The uniformity was a value obtained by dividing the 60% undersize particle size by the 10% undersize particle size. [5] Powder flowability: The movement of the polyethylene powder in the fluidized tank was visually observed and evaluated. Good: Powder in the tank flows evenly. Poor: Powder in the tank does not flow evenly, and the fluidized bed causes channeling and slacking.

Evaluation of sheet formed from powder [1] Constant strain environmental stress cracking time (ESCR) (h
r): Using a 3 mm-thick sheet molded from powder,
JIS K6760 The constant strain environmental stress crack test of Section 4.7 was conducted, and the constant strain environmental stress crack time was 50 sheets.
% Was the time at which the crack occurred. [2] Surface hardness: The surface hardness was determined by a durometer D hardness test according to JIS K6760 section 4.4 using a sheet formed from a powder and having a thickness of 3 mm. [3] Tensile properties: Tensile strength and elongation were determined by a tensile test according to JIS K6760 section 4.3 using a 2 mm thick sheet formed from powder. [4] Chemical resistance: using a 3 mm-thick sheet molded from a powder in gasoline at a temperature of 23 ° C. in accordance with JIS K7114, a plastic resistance test method.
Dipped for 0 days. The chemical resistance was calculated according to equation (1).

(Equation 1)

Method for measuring film properties of test piece (lining product) molded from powder [1] Impact strength: Measured according to JIS G3469. The test piece was placed on a flat wooden table, and a steel ball having a mass of 770 g was vertically dropped on the test piece from a height of 2050 mm. After applying the impact, it was examined by a holiday detector whether or not pinholes occurred in the coating of the lining product. Not destroyed means 1 by Holiday Detector
At an applied voltage of 2 KV, no pinhole is detected in the film. [2] Adhesive strength (N / 10 mm): A cut is made in the film of the test piece with a width of 10 mm using a cutter knife until reaching the steel plate. Peel off one end so as not to damage the film,
Peel strength was measured at an angle of 90 ° at a speed of 50 mm / min. The adhesive strength was the peel strength. [3] Film appearance: The appearance of the lining product obtained by powder molding was visually observed and evaluated. Good: The film surface is smooth and glossy. Poor: Unevenness is noticeable on the film surface.

In Examples 1 to 3 and Comparative Examples 1 and 2,
Table 1 shows the characteristics of the ethylene-α-olefin copolymer and the high-pressure low-density polyethylene used.

(Examples 1 to 3 and Comparative Examples 1 and 2) Production of Polyethylene Powder Ethylene-α-olefin copolymer and high-pressure low-density polyethylene, polystyrene / polyisoprene / polystyrene block shown in Table 1 Polymer (SIS) [manufactured by Shell Japan, product name: Kaliflex TR] and low-density polyethylene masterbatch (lubricant, pigment,
Antioxidant-containing low-density polyethylene) was blended with the composition shown in Table 2, and pelletized using a melt kneader. The pellets were pulverized at room temperature using a high-speed rotary pulverizer, and the polyethylene powder shown in Table 3 was produced by a classification method using a vibrating sieve. The obtained polyethylene powder was compression molded at a temperature of 165 ° C. to a thickness of 2 mm and 3 m.
m. The properties of the obtained sheet were evaluated, and the results are shown in Table 4.

(Examples 4 to 6 and Comparative Examples 3 and 4) Production of Powder Molded Article Using Polyethylene Powder A fluidized tank filled with the polyethylene powder shown in Table 3 and fluidized was previously heated at 275 ° C. A 6 mm thick steel sheet heated to a temperature was immersed for 30 seconds to prepare a test piece (lining product) coated with a polyethylene powder having a thickness of about 1 mm. The characteristics of the film were evaluated using the obtained test pieces, and the results are shown in Table 5.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

The polyethylene powder of the present invention has good fluidity, and a powder molded product using this powder has excellent surface smoothness.

The polyethylene powder of the present invention has excellent film appearance, excellent surface hardness, mechanical properties such as tensile strength and impact strength, chemical resistance such as constant strain environmental stress cracking (ESCR) and gasoline resistance. A powder compact having excellent properties and adhesive strength can be obtained.

The polyethylene powder of the present invention has strong adhesiveness by being formed and coated on a base metal such as a steel pipe, so that it can exhibit a stable anticorrosion performance for a long period of time.

Claims (2)

[Claims] 1. An ethylene-α-olefin copolymer produced by a metallocene catalyst having the following properties (A): 100 parts by weight, a high-pressure low-density polyethylene having the following properties (B): 0 to 3
A polyethylene powder having the following property (D), comprising a polyethylene composition containing 0 parts by weight and (C) 1 to 50 parts by weight of an elastomer. (A) Ethylene-α-olefin copolymer produced from a metallocene catalyst (A1) Density: 0.880 to 0.960 g / cm ³ (A2) Melt flow rate (MFR): 0.1 to 20
0 g / 10 min (B) High pressure method low density polyethylene (B1) Density: 0.900 to 0.940 g / cm ³ (B2) Melt flow rate (MFR): 0.1 to 10
0 g / 10 min (D) Polyethylene powder (D1) Bulk density: 0.20 to 0.50 (g / cm ³ ) 2. A powder molded product using the polyethylene powder according to claim 1.