JP2005097485A - Ethylene-based resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ethylene-based resin composition which has the excellent moldability, transparency and gloss and has the high heat resistance and impact resistance, and to provide a blow molded body obtained by blow-molding the composition. <P>SOLUTION: The ethylene-based resin composition comprises 97-70 % by weight of a polyethylene (A), which is manufactured by a high pressure radical polymerization method and which satisfies the following prerequisite (A-1) to prerequisite (A-4), and 3-30 % by weight of an ethylene/α-olefin copolymer (B); the blow-molded body is obtained by blow-molding it. Polyethylene prerequisite (A-1): the melt flow rate is 0.1-20 g/10 minutes. Prerequisite (A-2): the density is 925-940 kg/m<SP>3</SP>. Prerequisite (A-3): the swell ratio is 1.20-1.45. And the prerequisite (A-4): The ratio (Vvn/Vvd) of the numbers (Vvn) of vinyl groups per the numbers of carbons of 2,000 to the numbers (Vvd) of vinylidene groups per the numbers of carbons of 2,000, based on the infrared absorption spectrum, is 0.01-0.30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ethylene-based resin composition. More specifically, the present invention relates to an ethylene-based resin composition that is excellent in moldability, transparency, and gloss, and has high heat resistance and impact resistance.

High pressure radical polymerization polyethylene is widely used as a material shown in the following (1) to (12) and the like.
(1) Packaging materials such as standard bags, garbage bags, rice bags, bread packaging, inner bags, surface protection films, stretch films, wrap films, etc. (2) Materials used for heavy packaging for fertilizer, soil, etc. (3) Multifilm Agricultural materials such as water and irrigation tubes (4) Coat materials used for milk containers, juice containers, liquor containers, seasoning containers, etc. (5) Insulation materials such as power cables, communication cables, telephone wires (6) Caps and inner plugs Injection molding materials such as (7) Hollow molding container materials such as mayonnaise containers, ketchup containers, drum containers, etc. (8) Tube materials used for liquid storage and transportation, etc. (9) Pipe materials such as water pipes and gas pipes (10) Foam material used for cushioning material, etc. (11) Steel pipe coating material (12) Powder molding material

  These materials have many opportunities to be seen by humans, and in particular, materials having excellent transparency and gloss are required for films, sheet bags, containers, tubes, pipes, caps and the like.

  In addition, when a bag or container that is a molded product is dropped or bumped when used at room temperature or low temperature, a material having good impact resistance is required because it may be broken or cracked.

  In addition, heat resistance is required for retort containers and packaging filled with cooked foods and the like. Specifically, it is not deformed by heating during cooking, and in order to increase the fluidity of the filled food, That it can be filled with hot air, can be boiled to sterilize at high temperatures, does not cause fusing, deformation, whitening, etc., and does not cause deformation or fusion when used in high-temperature areas such as the tropics and deserts. Etc. are required.

  Furthermore, in order to supplement the impact resistance, rigidity, heat resistance, etc. of the high-pressure radical polymerization polyethylene used in the above material, a linear low density polyethylene which is a copolymer of ethylene and α-olefin is blended, It is known to use a resin composition comprising high-pressure radical polymerization polyethylene and linear low-density polyethylene.

  However, linear low-density polyethylene has a high extrusion load when it is extruded, a low melt tension, melt fracture occurs during molding, and the surface of the molded product may be roughened. The resin composition composed of high-pressure radical polymerization polyethylene and linear low-density polyethylene may also be somewhat inadequate in molding processability.

  For example, JP 2001-219514 A discloses a resin composition that can be used for both surface layers of a packaging film that is at least three layers in which rigidity is maintained at a practical level and excellent in transparency. A resin composition comprising an α-olefin copolymer and a high-pressure radical process low-density polyethylene having a terminal double bond of 0.2 to 1.0 / 2000 C is described.

  In addition, in the plastic material course 4 polyethylene resin (issued on August 30, 1969, page 18), as an initiator in the production of high-pressure polyethylene, 1 is generally used in a temperature range of 110 to 210 ° C. It is described that one having a half-life of minutes is good. That is, high-pressure radical polymerization polyethylene manufactured using an initiator having a half-life of 1 minute in a temperature range of 110 to 210 ° C. is described.

  However, even in the high-pressure radical polymerization polyethylene described in the resin composition and plastic material lecture 4 polyethylene resin described in JP 2001-219514 A, films, sheet bags, containers, tubes, pipes, Further improvements were required for moldability, transparency, gloss, heat resistance and impact resistance required for caps and the like.

JP 2001-219514 A Plastic material course 4 polyethylene resin (issued August 30, 1969, p. 18)

  An object of the present invention is to provide an ethylene resin composition having excellent moldability, transparency and gloss, high heat resistance and impact resistance, and a hollow molded body obtained by hollow molding the ethylene resin composition. There is to do.

As a result of intensive studies in view of such circumstances, the present inventors have found that the present invention can solve the above problems, and have completed the present invention.
That is, the present invention
97-70% by weight of polyethylene (A) produced by a high-pressure radical polymerization method and satisfying the following requirements (A-1) to (A-4), and the following requirements (B-1) to (B-3) And an ethylene resin composition containing 3 to 30% by weight of the ethylene / α-olefin copolymer (B) (provided that the total amount of the ethylene resin composition is 100% by weight) and the ethylene resin. The present invention relates to a hollow molded article obtained by hollow molding the composition. (Hereinafter, polyethylene (A) produced by the high pressure radical polymerization method is referred to as high pressure radical polymerization method polyethylene (A).)
Polyethylene (A)
Requirement (A-1) The melt flow rate is 0.1 to 20 g / 10 min.
A requirement (A-2) density is 925-940 kg / m < ³ >.
Requirement (A-3) The swell ratio is 1.20 to 1.45.
Requirement (A-4) The ratio (Vvn / Vvd) between the number of vinyl groups per 2000 carbon atoms (Vvn) and the number of vinylidene groups per 2000 carbon atoms (Vvd) determined by infrared absorption spectrum is 0.01-0.30.
Ethylene / α-olefin copolymer (B)
Requirement (B-1) The melt flow rate is 0.1 to 10 g / 10 min.
A requirement (B-2) density is 880-940 kg / m < ³ >.
Requirement (B-3) Melt flow rate ratio (MFRR) is 10-30.

  According to the present invention, an ethylene resin composition having excellent moldability, transparency and gloss, high heat resistance and impact resistance, and a hollow molded body obtained by hollow molding the ethylene resin composition are obtained. be able to.

  The melt flow rate (MFR) of the high-pressure radical polymerization polyethylene (A) used in the present invention is 0.1 to 20 g / 10 minutes (requirement (A-1)), preferably 0.15 to 10 g / 10. Minutes, more preferably 0.20 to 5 g / 10 minutes, and still more preferably 0.25 to 1 g / 10 minutes. When MFR is less than 0.1 g / 10 minutes, the transparency may be insufficient, and when it exceeds 20 g / 10 minutes, the strength of the molded article may be excessively reduced.

The density (d) of the high-pressure radical polymerization polyethylene (A) used in the present invention is 925 to 940 kg / m ³ (requirement (A-2)), preferably 926 to 935 kg / m ³ , more preferably. Is 927-930 kg / m ³ . When the density is less than 925 kg / m ³ , the rigidity is low and the handleability of the molded product may be insufficient, and when it exceeds 940 kg / m ³ , the impact strength may be reduced.

  The swell ratio (SR) of the high pressure radical polymerization polyethylene (A) used in the present invention is 1.20 to 1.45 (requirement (A-3)), preferably 1.22 to 1.40. More preferably, it is 1.25 to 1.38. When the swell ratio (SR) is less than 1.20 or exceeds 1.45, transparency may be insufficient.

  The melt flow rate (MFR) or swell ratio (SR) of the high pressure radical polymerization polyethylene (A) used in the present invention is adjusted by kneading the high pressure radical polymerization polyethylene (A) used in the present invention at least once. Can be done. Kneading is performed using a normal extruder or kneader, and examples of the extruder include a single-screw extruder, a co-directional twin-screw extruder, a different-direction twin-screw extruder, and the like. For example, a kneader type or Banbury type kneader may be used.

The high-pressure radical polymerization polyethylene (A) used in the present invention has the following characteristics with respect to the vinyl group, vinylidene group and transvinylene group contained in the polyethylene.
The ratio (Vvn / Vvd) of the number of vinyl groups per 2000 carbon atoms (Vvn) determined by infrared absorption spectrum to the number of vinylidene groups per 2000 carbon atoms (Vvd) is 0.01-0. 30 (requirement (A-4)). This ratio (Vvn / Vvd) is preferably 0.05 to 0.20. If this ratio (Vvn / Vvd) exceeds 0.30, heat resistance, transparency and gloss may deteriorate, and if this ratio (Vvn / Vvd) is less than 0.01, it may be difficult to manufacture. is there.

  In addition, from the viewpoint of heat resistance, transparency, gloss, or ease of production, the number of vinyl groups per 2000 carbon atoms (Vvn) determined by infrared absorption spectrum and the transformer per 2000 carbon atoms. The ratio (Vvn / Vtv) to the number of vinylene groups (Vtv) is preferably 0.01 to 1.30, more preferably 0.10 to 1.20.

  In addition, from the viewpoint of heat resistance, transparency, gloss, or ease of production, the number of transvinylene groups per 2000 carbon atoms (Vtv) required by the infrared absorption spectrum and per 2000 carbon atoms The ratio (Vtv / Vvd) to the number of vinylidene groups (Vvd) is preferably 0.01 to 0.24, more preferably 0.12 to 0.19.

  In addition, from the viewpoint of rigidity, ease of production, or thermal stability, the number of vinyl groups per 2000 carbon atoms (Vvn) determined by infrared absorption spectrum and the vinylidene group per 2000 carbon atoms The sum (Vvn + Vvd + Vtv) of the number (Vvd) and the number of transvinylene groups per 2000 carbon atoms (Vtv) is preferably 0.05 to 0.50, more preferably 0. .20-0.38.

  And from the viewpoint of heat resistance, transparency, gloss, or ease of production, the number of vinylidene groups per 2000 carbon atoms (Vvd) determined by infrared absorption spectrum is preferably 0.04 to 2 0.00, more preferably 0.10 to 1.00, and still more preferably 0.15 to 0.40.

  The high-pressure radical polymerization polyethylene (A) used in the present invention is a radical having a half-life of 10 seconds or less at a reaction temperature of 210 to 300 ° C. by pressurizing ethylene to 50 to 400 MPa with a multistage gas compressor. It is produced by polymerizing ethylene using at least two generators.

  The reaction pressure in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention is 50 to 400 MPa, preferably 180 to 400, from the viewpoint of controlling the requirements of the polyethylene (A), production equipment and safety. 300 MPa, more preferably 220 to 255 MPa.

  The reaction temperature in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention is 210 to 300 ° C., preferably 210 to 270 ° C. from the viewpoint of controlling the requirements of polyethylene (A) and productivity. More preferably, it is 210-255 degreeC.

The high-pressure radical polymerization polyethylene (A) used in the present invention is produced by polymerizing ethylene using at least two radical generators having a half-life of 10 seconds or less at the reaction temperature.
The half life at the reaction temperature of the radical generator used in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention is preferably 5 seconds or less, more preferably 1 second or less.

  Examples of the radical generator used in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention include di-t-butyl peroxide, t-butyl hydroperoxide, and t-butyl-peroxy-2-ethyl. Organic peroxides such as hexanate, dicumyl peroxide, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, di-t-amyl peroxide, cumyl hydroperoxide, t-butyl peroxybivalate And oxygen.

  At least two kinds of radical generators used in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention are used, and at least two kinds of radical generators may be used sequentially, and at least two kinds thereof may be used. You may mix and use. And also when introducing into a polymerization reactor, you may introduce from one place and may introduce from several places. Moreover, when introducing into a polymerization reactor, you may melt | dissolve in a solvent etc. and use.

  In order to adjust the molecular weight of the high-pressure radical polymerization polyethylene (A) used in the present invention, a chain transfer agent may be used in its production. Examples of the chain transfer agent include saturated hydrocarbons, aromatic hydrocarbons, alcohols and the like. Examples of saturated hydrocarbons include alkanes such as ethane, propane, n-butane, n-hexane, n-heptane, and isobutane, and cyclic alkanes such as cyclohexane. Examples of aromatic hydrocarbons include benzene, toluene, xylene, and ethylbenzene. Examples of alcohols include methanol and ethanol. Moreover, organic compounds containing hetero atoms such as tetrahydrofuran and acetone, hydrogen, and the like are also included. The chain transfer agent is preferably a saturated hydrocarbon, more preferably an alkane.

  Examples of the reaction vessel used in the production of the high-pressure radical polymerization polyethylene (A) used in the present invention include a tank-type reaction vessel and a tube-type reaction vessel, and a tube-type reaction vessel is preferable.

  The ethylene / α-olefin copolymer (B) used in the present invention is an ethylene / α-olefin copolymer obtained by polymerizing ethylene and at least one α-olefin having 3 to 12 carbon atoms. . Examples of the α-olefin having 3 to 12 carbon atoms include propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, dodecene-1, 4 -Methyl-pentene-1,4-methyl-hexene-1 and the like are mentioned, and preferably hexene-1 and octene-1.

  Examples of the ethylene / α-olefin copolymer (B) used in the present invention include an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, an ethylene-hexene-1 copolymer, and an ethylene-octene- 1 copolymer etc. are mentioned, Preferably they are an ethylene-hexene-1 copolymer and an ethylene-octene-1 copolymer.

  The melt flow rate (MFR) of the ethylene / α-olefin copolymer (B) used in the present invention is 0.1 to 10 g / 10 min (requirement (B-1)), preferably 0.3 to 5 g. / 10 minutes, more preferably 0.5 to 1 g / 10 minutes. When the MFR is less than 0.1 g / 10 minutes, the extrusion load may be excessively high in extrusion molding. When the MFR exceeds 10 g / 10 minutes, the strength of the molded product may be excessively reduced.

The density (d) of the ethylene / α-olefin copolymer (B) used in the present invention is 880 to 940 kg / m ³ (requirement (B-2)), preferably 885 to 930 kg / m ³ , More preferably, it is 890-925 kg / m < ³ >. If the density is less than 880 kg / m ³ , the rigidity may be excessively low, or the handleability of the molded product may be insufficient. If it exceeds 940 kg / m ³ , the transparency and impact strength of the molded product will decrease. There are things to do.

  The melt flow rate ratio (MFRR) of the ethylene / α-olefin copolymer (B) used in the present invention is 10 to 30 from the viewpoint of suppressing the extrusion load in extrusion molding and the transparency or strength of the molded product. (Requirement (B-3)), preferably 12 to 25 g / 10 min, and more preferably 14 to 20.

  Ratio (Mw / Mn) of weight average molecular weight (Mw) and number average molecular weight (Mn) determined by gel permeation chromatography (GPC) of the ethylene / α-olefin copolymer (B) used in the present invention ) Is preferably 1.5 to 3.5, more preferably 1.6 to 3.0, and still more preferably 1.8 from the viewpoint of extrusion load and impact resistance and transparency of the molded product. ~ 2.5.

  Examples of the method for producing the ethylene / α-olefin copolymer (B) used in the present invention include a method for producing by a known polymerization method using a known polymerization catalyst.

Examples of known polymerization catalysts include Ziegler-Natta catalysts, chromium catalysts, metallocene catalysts, and the like.
Examples of the Ziegler-Natta catalyst include the following catalyst system (1) or (2).
(1) A catalyst system comprising a component in which at least one selected from the group consisting of titanium trichloride, vanadium trichloride, titanium tetrachloride, and a halo alcoholate of titanium is supported on a magnesium compound carrier, and an organometallic compound as a cocatalyst. (2) Catalyst system comprising a coprecipitate of a magnesium compound and a titanium compound or an eutectic and an organometallic compound as a cocatalyst

  Examples of the chromium-based catalyst include a catalyst system comprising a component in which a chromium compound is supported on silica or silica-alumina, and an organometallic compound as a cocatalyst.

Examples of the metallocene catalyst include the following catalyst systems (1) to (4).
(1) A catalyst system comprising a component containing a transition metal compound having a group having a cyclopentadiene skeleton and a component containing an alumoxane compound. (2) A component containing the transition metal compound and ions such as trityl borate and anilinium borate. catalyst system comprising components including sexual compound (3) and component comprising the transition metal compound, and a component containing an ionic compound, a catalyst system consisting of components including an organic aluminum compound (4) of each component of the SiO ₂ Catalyst system obtained by supporting or impregnating inorganic particulate carriers such as Al ₂ O ₃ and particulate polymer carriers such as olefin polymers such as ethylene and styrene

  Examples of known polymerization methods used in the production of the ethylene / α-olefin copolymer (B) used in the present invention include a liquid phase polymerization method, a slurry polymerization method, a gas phase polymerization method, and a high pressure ion polymerization method. Either a batch polymerization method or a continuous polymerization method may be used, and a multistage polymerization method having two or more steps may also be mentioned.

The content of the high-pressure radical polymerization polyethylene (A) and the ethylene / α-olefin copolymer (B) in the ethylene-based resin composition of the present invention is 97 to 70% by weight of the high-pressure radical polymerization polyethylene (A). The ethylene / α-olefin copolymer (B) is 3 to 30% by weight. Preferably, polyethylene (A) is 95 to 75% by weight, and copolymer (B) is 5 to 25% by weight.
When the polyethylene (A) exceeds 97% by weight (that is, when the copolymer (B) is less than 3% by weight), the impact resistance may be insufficient, and the polyethylene (A) is less than 70% by weight. In some cases (that is, when the copolymer (B) exceeds 30% by weight), moldability and heat resistance may be insufficient.

  The ethylene-based resin composition of the present invention, the high-pressure radical polymerization polyethylene (A) used in the present invention, or the ethylene / α-olefin copolymer (B) used in the present invention may include a high-pressure radical as necessary. Other resins than the polymerized polyethylene and ethylene / α-olefin copolymer may be added. For example, polypropylene or high density polyethylene added to improve rigidity, ethylene / α-olefin copolymer added to improve mechanical strength, low density elastomer added to improve impact strength And other polyolefin-based resins. These other resins may be added alone or in combination of at least two kinds.

The ethylene-based resin composition of the present invention, the high-pressure radical polymerization polyethylene (A) used in the present invention or the ethylene / α-olefin copolymer (B) used in the present invention is optionally provided with a stabilizer. Further, a lubricant, an antistatic agent, a processability improving agent, an antiblocking agent and the like may be added.
Examples of the stabilizer include 2,6-di-t-butyl-p-cresol (BHT), tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane ( Ciba Specialty Chemicals, trade name: IRGANOX1010) and n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate (Ciba Specialty Chemicals, trade name) : Phenyl stabilizers such as IRGANOX 1076), phosphite stabilizers such as bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and tris (2,4-di-t-butylphenyl) phosphite Agents.

  As the lubricant, an organic fatty acid amide may be used. Examples of organic fatty acid amides include saturated fatty acid amides, unsaturated fatty acid amides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. These may be used alone or in combination of at least two kinds.

Examples of the saturated fatty acid amide include stearic acid amide and behenic acid amide, and examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Examples of the saturated fatty acid bisamide include ethylene bis stearic acid amide, and examples of the unsaturated fatty acid bisamide include ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl sebacic acid amide. Etc. Among these, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, and ethylenebisoleic acid amide are preferable.
The blending amount of the organic fatty acid amide is usually 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the high-pressure radical polymerization polyethylene of the present invention.

  Examples of the antistatic agent include glycerin esters, sorbitan acid esters and polyethylene glycol esters of fatty acids having 8 to 22 carbon atoms, and examples of the processability improver include fatty acid metal salts such as calcium stearate, Examples of the anti-blocking agent include silica, calcium carbonate, talc and the like.

The ethylene-based resin composition of the present invention, the high-pressure radical polymerization polyethylene (A) used in the present invention or the ethylene / α-olefin copolymer (B) used in the present invention is added as necessary. Examples of methods for adding other resins and stabilizers, lubricants, antistatic agents, processability improvers, anti-blocking agents, etc. include, for example, the high-pressure radical polymerization polyethylene of the present invention, other resins, stabilizers, lubricants, Examples thereof include a method of melt-kneading an antistatic agent, a processability improving agent, an antiblocking agent and the like, and a method of dry blending.
There is also a method in which at least one masterbatch such as other resins, stabilizers, lubricants, antistatic agents, processability improvers, antiblocking agents, etc. is prepared and this masterbatch is dry blended with high pressure radical polymerization polyethylene. Can be mentioned.

  Examples of the method for molding the ethylene resin composition of the present invention include an inflation film molding method, a T-die cast film molding method, a blow molding method, an extrusion molding method such as a tube molding method, an injection molding method, and a hot press molding method. Etc.

  In particular, in the molding method in which the molten resin of the ethylene resin composition of the present invention is rapidly cooled, the effects of the present invention are remarkably exhibited. Molding methods for rapidly cooling the molten resin include, for example, a water-cooled inflation film molding method and a tube molding method for cooling the molten resin with water, a T-die cast film molding method for pressing the molten resin against a cooled metal, and a cooled mold. Examples thereof include a blow molding method, an injection molding method, and a hot press molding method using a cooling press.

Examples of the use of the ethylene-based resin composition of the present invention include the following uses (1) to (13).
(1) Packaging materials such as standard bags, garbage bags, rice bags, bread packaging, inner bags, surface protection films, stretch films, wrap films, etc. (2) Materials used for heavy packaging for fertilizer, soil, etc. (3) Multifilm (4) Coat materials used for milk containers, juice containers, liquor containers, seasoning containers, etc. (5) Insulating materials such as power cables, communication cables and telephone lines (6) Caps, inner plugs Injection molding materials such as (7) Hollow molding container materials such as mayonnaise containers, ketchup containers, drum containers, etc. (8) Tube materials used for liquid storage and transportation, etc. (9) Pipe materials such as water pipes and gas pipes (10) Foam material used for cushioning material, etc. (11) Steel pipe coating material (12) Powder molding material (13) Extruded material

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.
The physical properties of the high-pressure radical polymerization polyethylene (A), the ethylene / α-olefin copolymer (B), and the ethylene resin composition of the present invention used in Examples and Comparative Examples were measured by the following methods.

(1) Density (d, unit: kg / m ³ )
The measurement was performed according to JIS K6760. After annealing in boiling water at 100 ° C. for 1 hour, it was used for measurement.

(2) Melt flow rate (MFR, unit: g / 10 minutes)
It measured according to JIS K7210. The test load was 21.18 N (2.16 kgf), and the measurement temperature was 190 ° C.

(3) Melt flow rate ratio (MFRR)
It measured according to JIS K7210. The value obtained by dividing the value measured under the conditions of a test load of 211.82N (21.60 kgf) and a measurement temperature of 190 ° C by the value measured under the conditions of a test load of 21.18N (2.16 kgf) and a measurement temperature of 190 ° C is MFRR. It was.

(4) Swell ratio (SR)
Using the melt flow rate measuring device specified in JIS K7210, the diameter D of the extruded strand at the time of measuring the melt flow rate is measured, and the ratio of the diameter D _{0 of} the orifice to the diameter D of the strand (D / D ₀ ) is swelled. The ratio (SR) was used. The measurement temperature was 190 ° C.

(5) Melting temperature (unit: ° C)
The melting temperature was measured using a DSC-7 differential scanning calorimeter (DSC) manufactured by PerkinElmer. About 10 mg of a test piece cut out from a sheet having a thickness of about 0.3 mm prepared by hot pressing is placed in a DSC measurement sample pan, pre-melted by holding at 150 ° C. for 5 minutes in the DSC, at 1 ° C./min. The temperature was lowered to 40 ° C., held for 5 minutes, and then heated to 150 ° C. at a rate of 10 ° C./min to obtain a thermogram. With respect to the thermogram at the time of temperature increase, the temperature at which the melting endothermic peak was the largest was taken as the melting temperature.

(6) Gel Permeation Chromatography (GPC) Measurement As a device for gel permeation chromatography (GPC, Gel Permeation Chromatography), measurement was performed using a 150C type manufactured by Waters. . Ortho-dichlorobenzene was used as an elution solvent, and measurement was performed under conditions of a measurement temperature of 140 ° C. and a flow rate of 1 mL / min. For the measurement, a column in which two TSK-GEL GMH-HT7.5 × 600 columns made by Tosoh Corporation were connected was used, and no guard column was used. After preparing a calibration curve of two columns connected in advance using a standard polystyrene with a narrow molecular weight distribution (TSO STANDARD POLYSTYRNE manufactured by Tosoh Corporation) whose molecular weight distribution can be regarded as monodisperse, a sample concentration of 0.1 g / L, injection amount of 0. Measurement was performed under the condition of 5 mL. The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the target sample were calculated based on the calibration curve with a polystyrene Q-factor of 41.3 and a polyethylene Q-factor of 17.7. The Q-factor was referred to Sadao Mori “Size Exclusion Chromatography—High Performance Liquid Chromatography of Polymers” (1991, Kyoritsu Shuppan Co., Ltd.). As the molecular weight distribution, a value (Mw / Mn) obtained by dividing the obtained weight average molecular weight (Mw) by the number average molecular weight (Mn) was obtained.

(7) Haze (degree of stagnation, unit:%)
Measured according to ASTM D1003. It shows that transparency is so good that this value is small.

(8) Gloss (Glossiness, Unit:%)
It measured according to JIS K7105. The 45-degree specular gloss was measured, and this value was defined as a Gloss value. The larger this value, the better the gloss.

(9) Flexural rigidity (unit: MPa)
The flexural rigidity was measured using an Olsen bending tester according to ASTM D747-70. The sample was molded into a 1 mm thickness at 150 ° C. with a hot press and annealed in boiling water at 100 ° C. for 1 hour. A larger value indicates higher rigidity and lower back.

(10) Melt tension (unit: cN)
Using a melt tension tester manufactured by Toyo Seiki Seisakusho, a certain amount of polymer was forcibly extruded from the orifice hole at a temperature of 190 ° C., and the tension generated when it was pulled into a monofilament shape was detected with a strain gauge. The tension was measured while increasing the take-up speed by a take-up roll at a constant rate until the monofilament-shaped molten polymer was cut, and the maximum value of the tension measured from the start of take-up to cutting was taken as the melt tension.
Extrusion speed: 0.32 g / min
Orifice: Diameter 2.095 mm, length 8.000 mm
Take-up ascent speed: 6.3 m / min
A higher value indicates a melt tension. If the melt tension is too high, the take-up property may be deteriorated, so that an appropriate value is desirable.

(11) Brabender torque (unit: Nm)
Using a Brabender Plastograph manufactured by Brabender, kneading is performed at 160 ° C. and 60 rpm, and the torque value after 30 minutes is measured. It shows that extrusion load is so small that this value is small.

(12) Quantification of vinyl group, vinylidene group, and trans vinylene group (unit: pieces / 2000 carbon)
The sample used for the measurement of the infrared absorption spectrum was molded to about 0.5 mm using a heat press at 150 ° C. The infrared absorption spectrum was measured with transmitted light using an FT / IR-480PLUS type Fourier transform infrared spectrophotometer manufactured by JASCO Corporation with a total number of 128 times and a resolution of 4 cm ⁻¹ .
From the obtained infrared absorption spectrum, absorption bands in the 910 cm ^-1 corresponding to vinyl groups, absorption band of 888 cm ^-1 corresponding to vinylidene group, the absorption band of 965 cm ^-1 corresponding to trans-vinylene group, from each of the baseline of each absorption band Absorbance, A ₉₁₀ , A ₈₈₈ and A ₉₆₅ were determined. Since the absorption intensity of each band differs depending on the sample, the respective baselines of each absorption band are straight lines in contact with the absorption curve at two points on the high wave number side and the low wave number side of each band, and in the vicinity of 900 cm ⁻¹ and 918 cm in the vinyl group. tangent in the vicinity of ^-1, tangent in the vicinity 875Cm ^-1 and around 900 cm ^-1 in the vinylidene group was determined as the tangent in the vicinity 948Cm ^-1 and around 980 cm ^-1 in the trans-vinylene group.
Using the following formulas (1) to (3), the number of vinyl groups, vinylidene groups, and transvinylene groups per 2000 carbon of polyethylene was determined from the absorbance from the baseline of each absorption band.
Number of vinyl groups per 2000 carbons: Vvn
Vvn = 0.231 / (d × l) × A ₉₁₀ formula (1)
Number of vinylidene groups per 2000 carbons: Vvd
Vvd = 0.271 / (d × l) × A ₈₈₈ formula (2)
Number of transvinylene groups per 2000 carbons: Vtv
Vtv = 0.328 / (d × l) × A ₉₆₅ formula (3)
In the formulas (1) to (3), d represents the density (g / cm ³ ) of the sample, and l represents the thickness (cm) of the sample measured using a micrometer.

(13) 80 ° C. torsional rigidity (unit: MPa)
The 80 ° C. torsional rigidity was measured at a measurement temperature of 80 ± 1 ° C. The conditions other than the measurement temperature were measured according to the method described in JIS K6730. The sample was molded by hot pressing at 150 ° C. and stored for 24 hours or more in a temperature-controlled room with a temperature of 23 ° C. and a humidity of 50%, and then used for measurement.
The larger this value, the higher the rigidity at 80 ° C. and the greater the heat resistant rigidity.

(14) Tensile impact strength (unit: kJ / m ² )
Measurement of tensile impact strength was performed at 23 ° C. in the form of an S-type dumbbell according to ASTM D1822-61T. The sample piece was molded by hot pressing at 150 ° C., stored in a temperature-controlled room at 23 ° C. and 50% humidity for 24 hours or more, and then used for measurement.

(15) Bottle thermal expansion (unit: mm)
Measurement of the amount of thermal expansion of the bottle obtained by hollow molding was performed according to the following method.
Hold the mouth of the bottle obtained by hollow molding with tweezers, fill the bottle with hot water of about 85 ° C while keeping the bottle suspended in the air, and leave it in the air It was kept for a minute, then placed on a sink and cooled with running water for 3 minutes, pouring from the mouth. After confirming that the bottle was sufficiently cooled, the amount of expansion of the bottle was measured. The distance (mm) between the horizontal plane including the central part of the bottom of the bottle with the largest expansion and the horizontal plane including the bottom peripheral part of the bottle with the smallest expansion was measured to obtain the amount of expansion.

(16) Melt Fracture Judging from the appearance of the bottle obtained by hollow molding, the case where the stripe pattern by the melt fracture was clearly observed was evaluated as x, and the case where the stripe pattern was not observed was evaluated as ◯.

(17) Drop strength of the bottle Evaluation of the drop strength of the bottle obtained by hollow molding was performed according to the following method.
Bottles obtained by hollow molding were filled with 500.0 to 500.2 g of drinking water, rubber packing was placed, and the cap was closed. After holding this bottle in a thermostatic bath at 5 ° C. for 12 hours or more, first, the bottle was placed in the vertical direction (with the mouth of the bottle facing up) and dropped from a height of 1.5 m for a test. . At this time, if no pinholes or cracks occurred in the bottle, the bottle was turned sideways (with the mouth lying sideways), and a drop test was conducted from a height of 1.5 m. At this time, if a pinhole or a crack did not occur in the bottle, a drop test was conducted from 1.5 m with the bottle again in the vertical direction. If no pinholes or cracks occurred, the drop test was conducted from 1.5 m with the bottle again in the horizontal direction. In this way, the bottle is alternately tested in the vertical and horizontal directions until the total number of vertical and horizontal drop tests reaches 20, and the bottle is evaluated for pinholes and cracks. It was. The test was carried out for 5 bottles for each sample.
Based on the result of the drop test, the drop strength index was obtained from the following equation (4).
20
(Drop strength index) = Σ W (m) Formula (4)
m = 1
W (m): Number of unbroken bottles in 5 bottles after falling m times If one of the 5 bottles does not break after 20 drops, (drop strength index) = 100, and all 5 bottles If it breaks in the first drop, (drop strength index) = 0.
The case where the drop strength index was 0 or more and less than 33 was determined as “drop strength: x”, the case where it was 33 or more and less than 66 was determined as “drop strength: Δ”, and the case where it was 66 or more and 100 or less was determined as “drop strength: ○”.

(18) Half-life The half-life at the reaction temperature was determined as follows.
The half-life was calculated for each organic peroxide used in the polymerization based on data of a benzene solution having an initial peroxide concentration of 0.1 mol / L. Specifically, a half-life of 1 minute in a benzene solution having an initial peroxide concentration of 0.1 mol / L described in “Organized oxide” (issued by Chemical Industry Co., Ltd.) edited by an organic peroxide research group, From the temperature for obtaining a half-life of 10 hours and a half-life of 100 hours, the relationship between the temperature (T (° C)) and the half-life (t _(1/2) (seconds)) is obtained, and based on that, the target temperature The half-life of was determined.
First, the relationship between the temperature (T (° C.)) and the half-life (t _1/2 (seconds)) is represented by the natural logarithm of the half-life (ln) with respect to the reciprocal of the temperature (1 / (T + 273.15) (1 / ° C.)). (T _1/2 )) was plotted, and a linear approximation was performed on the plot to obtain a relationship between 1 / (T + 273.15) and ln (t _1/2 ). The relationship between the obtained temperature (T (° C.)) and half-life (t _(1/2) (seconds)) was taken as the relationship between reaction temperature and half-life, and the half-life at the reaction temperature was determined.

(19) Hot press (19-1) Press sheet used for measuring physical properties other than infrared absorption spectrum The press sheet used for measuring physical properties other than infrared absorption spectrum is molded as follows using a hot press. It was.
Put the sample in a spacer frame with thickness and frame shape suitable for each measurement, sandwich the spacer and sample with polyethylene terephthalate film, sandwich it with 0.3 mm thick aluminum plate, and further 3 mm A thick SUS plate was hot pressed. The heat press was preheated by holding for 5 minutes at 150 ° C. in a non-pressurized state at 150 ° C. using a hot press molding machine manufactured by Shindo Metal Industry Co., Ltd., and then pressurized to 100 kg / cm ^2. Molded for 5 minutes. Immediately after the lapse of 5 minutes in the pressurized state, the sample was pressed for 5 minutes with a cooling press in which cooling water of 30 ° C. was passed.

(19-1) Press sheet used for measurement of infrared absorption spectrum The press sheet used for measurement of infrared absorption spectrum was molded as follows using a hot press.
Place the sample in the frame of a spacer with a thickness of 0.5 mm, sandwich the spacer and the sample with an aluminum foil so that the non-mirror surface touches the sample, and place it with an aluminum plate with a rough surface of 1 mm. The scissors were further hot pressed with a 3 mm thick SUS plate sandwiched between them. The heat press was preheated by holding for 5 minutes at 150 ° C. in a non-pressurized state at 150 ° C. using a hot press molding machine manufactured by Shindo Metal Industry Co., Ltd., and then pressurized to 100 kg / cm ^2. Molded for 5 minutes. Immediately after the lapse of 5 minutes in the pressurized state, the sample was pressed for 5 minutes with a cooling press in which cooling water of 30 ° C. was passed.

[A1]
The high-pressure radical polymerization polyethylene (A1) used in Examples 1 to 3 and Comparative Examples 1 and 4 to 8 of the present invention was produced as follows. Using a tubular reactor, the polymerization pressure was 240 MPa, the polymerization temperature was 225 ° C., t-butyl peroxyisopropyl carbonate (half-life at 225 ° C. 0.157 seconds) and t-butyl peroxypivalate (at 225 ° C. Polymerization was carried out using a half-life of 0.009 seconds and t-butylperoxy-2-ethylhexanate (a half-life of 0.006 seconds at 225 ° C.) as a radical generator and propane as a chain transfer agent. The physical properties are shown in Table 1.

[A2]
In Comparative Example 1, Sumikacene F102-0 manufactured by Sumitomo Chemical Co., Ltd. was used as high-pressure radical polymerization polyethylene (A2). The physical properties are shown in Table 1.

The following (B1) to (B3) were used as the ethylene / α-olefin copolymer (B). These physical properties are shown in Table 2.
B1: Ethylene / 1-hexene copolymer excelen FX CX1001 manufactured by Sumitomo Chemical Co., Ltd.
B2: Sumitomo Mitsui Polyolefin Co., Ltd. Ethylene / 1-hexene copolymer Evolue SP0510
B3: Ethylene / 1-butene copolymer Exelen VL VL100 manufactured by Sumitomo Chemical Co., Ltd.

Examples 1-2 and Comparative Examples 1-5
Examples 1 to 2 and Comparative Examples 1 to 5 were obtained by granulating and kneading at 210 ° C. using a resin composition shown in Table 3 and using a dalmage type screw in a 30 mmφ single screw granulator. It was.
Measurement of melt tension, 80 ° C. torsional rigidity, and tensile impact strength of resin composition samples used in Examples 1-2 and Comparative Examples 1-5, and a 0.5 mm thick press sheet prepared by hot pressing Haze and Gloss were evaluated. The results are shown in Table 3.

Example 3 and Comparative Examples 6-8
In Example 3 and Comparative Examples 6-8, using the resin composition shown in Table 4, each component was blended in a pellet state, and hollow molding was performed.
Hollow molding was performed as follows. Using a NB-3B hollow molding machine manufactured by Nippon Steel Works, a 50 mmφ extruder, a 500 ml round bottle was hollow molded. Each of the two divided molds was molded by attaching a 7 × 5 cm label with a thickness of 100 μm to a portion corresponding to the barrel of the round bottle so that two concave depressions were formed on the molded product. The temperature of the extruder was set at cylinder 1: 170 ° C., cylinder 2: 190 ° C., cylinder 3: 210 ° C., adapter: 210 ° C., crosshead: 210 ° C. The die heater current was controlled so that the die did not fall below 210 ° C. Using a circular die having a die inner diameter of 17 mmφ and a core of 15 mmφ, the core was molded at a discharge rate of 8 kg / hr and a mold temperature of 30 ° C. A bottle with a basis weight of 20 g was obtained using a parison control.

  The bottles of Example 3 and Comparative Examples 5-8 thus obtained were allowed to stand in a temperature-controlled room at 23 ° C. and 50% humidity for at least 24 hours, and then observed for occurrence of melt fracture of the bottles, drop strength of the bottles, and coefficient of thermal expansion. The haze of the sample cut from the body of the bottle into a sheet shape and the gloss of the outer surface of the bottle were measured. The results are shown in Table 4.

  It can be seen that the resin compositions of Examples 1 and 2 that satisfy the requirements of the present invention are excellent in moldability, transparency, and gloss, and have high heat resistance and impact resistance.

  Comparative Example 1 is a resin composition that does not contain the ethylene / α-olefin copolymer (B) that is a requirement of the present invention, using only the high-pressure radical polymerization polyethylene (A1) that satisfies the requirements of the present invention, The tensile impact strength was insufficient.

  Comparative Example 2 is a high-pressure radical polymerization polyethylene (A2) that does not satisfy the requirements (density, SR, vinyl group number (Vvn) and vinylidene group number (Vvd) ratio (Vvn / Vvd)) of the present invention. Is a resin composition that does not contain an ethylene / α-olefin copolymer (B), has a low torsional rigidity at 80 ° C., insufficient heat resistance, a large Haze value, insufficient transparency, and a Gloss value. And gloss was insufficient.

  Comparative Example 3 is a high-pressure radical-polymerized polyethylene (A2) that does not satisfy the requirements (density, SR, vinyl group number (Vvn) and vinylidene group number (Vvd) ratio (Vvn / Vvd)). The resin composition used had low torsional rigidity at 80 ° C. and insufficient heat resistance.

  Comparative Example 4 is a resin composition using an ethylene / α-olefin copolymer (B3) that does not satisfy the melt flow rate ratio (MFRR), which is a requirement of the present invention, and has low tensile impact strength and impact resistance. It was insufficient.

  Comparative Example 5 is a resin composition in which the content of the high-pressure radical polymerization polyethylene (A1) and the ethylene / α-olefin copolymer (B1) does not satisfy the requirements of the present invention, and the heat resistance at 80 ° C. is low and the heat resistance is low. The sex was insufficient.

  Example 3 which is a blow bottle (hollow molded product) obtained by hollow molding a resin composition satisfying the requirements of the present invention is excellent in moldability, transparency and gloss, and has high heat resistance and impact resistance. It turns out that it is a hollow molded object.

  Comparative Example 6 is a bottle obtained by hollow molding a resin composition not containing an ethylene / α-olefin copolymer (B) using only high-pressure radical polymerization polyethylene (A1) that satisfies the requirements of the present invention. The drop strength was insufficient.

  Comparative Example 7 is a bottle obtained by hollow molding a resin composition containing an ethylene / α-olefin copolymer (B3) that does not satisfy the melt flow rate ratio (MFRR) that is a requirement of the present invention, The strength was insufficient.

  Comparative Example 8 is a bottle obtained by hollow molding a resin composition in which the content of the high pressure radical polymerization polyethylene (A1) and the ethylene / α-olefin copolymer (B1) does not satisfy the requirements of the present invention. In addition, the amount of thermal expansion was large and the heat resistance was insufficient, melt fracture occurred, and the moldability was insufficient.

Claims (2)

97-70% by weight of polyethylene (A) produced by a high-pressure radical polymerization method and satisfying the following requirements (A-1) to (A-4), and the following requirements (B-1) to (B-3) An ethylene-based resin composition containing 3 to 30% by weight of an ethylene / α-olefin copolymer (B) satisfying (However, the total amount of the ethylene resin composition is 100% by weight.)
Polyethylene (A)
Requirement (A-1) The melt flow rate is 0.1 to 20 g / 10 min.
A requirement (A-2) density is 925-940 kg / m < ³ >.
Requirement (A-3) The swell ratio is 1.20 to 1.45.
Requirement (A-4) The ratio (Vvn / Vvd) between the number of vinyl groups per 2000 carbon atoms (Vvn) and the number of vinylidene groups per 2000 carbon atoms (Vvd) determined by infrared absorption spectrum is 0.01-0.30.
Ethylene / α-olefin copolymer (B)
Requirement (B-1) The melt flow rate is 0.1 to 10 g / 10 min.
A requirement (B-2) density is 880-940 kg / m < ³ >.
Requirement (B-3) Melt flow rate ratio (MFRR) is 10-30.   A hollow molded article obtained by hollow molding of the ethylene-based resin composition according to claim 1.