WO2012117985A1 - Polyethylene-based resin composition for blow molding and blow molded body - Google Patents

Abstract

A polyethylene-based resin composition for blow molding containing 5 to 49% by mass of an aliphatic polyester (A), 50 to 94% by mass of a following component (B), and 1 to 15% by mass of a compatibilizing agent (C) (provided that the total amount of the aliphatic polyester (A), the component (B), and the component (C) is 100% by mass).

Description

Polyethylene resin composition for hollow molding and hollow molded body

The present invention relates to a polyethylene resin composition for hollow molding and a hollow molded body.

A molded article made of a resin composition containing polyethylene and a plant-derived resin such as polylactic acid or poly-3-hydroxybutyrate is more than a molded article made of a resin composition containing polyethylene and no plant-derived resin. It is known that the disposal process is easy.
As a resin composition containing polyethylene and a plant-derived resin, resin compositions described in JP 2008-38142 A and WO 09/078376 are known. Patent Document 1 discloses a resin composition comprising 10 to 70 parts by mass of a polylactic acid resin, 90 to 30 parts by mass of a polyethylene resin, and 5 to 10 parts by mass of a compatibilizer. In Patent Document 2, a polyolefin polymer (A), an aliphatic polyester polymer (B), and a melt flow rate (MFR) measured at 190 ° C. under a load of 21 N are 0.5 to 3.0 g / 10. The resin composition containing the elastomer (C) which is a part, and the polyolefin-type polymer (D) which has an epoxy group is disclosed.

However, the buckling strength and impact strength of hollow molded articles obtained by hollow molding of the resin compositions described in JP-A-2008-38142 and WO09 / 078376 are not sufficient, and these physical properties are further improved. There was a need for improvement.
In view of the above problems, an object of the present invention is to provide a hollow molded article having excellent buckling strength and impact strength.
The present invention relates to a hollow molding polyethylene resin containing 5-49% by mass of an aliphatic polyester (A), 50-94% by mass of the following component (B), and 1-15% by mass of a compatibilizer (C). A composition (provided that the total amount of the aliphatic polyester (A), the component (B) and the component (C) is 100% by mass) is provided.
Component (B): an ethylene-α-olefin copolymer having a density of 880 to 965 kg / m ³ , a melt flow rate of 0.01 to 5 g / 10 min, and a melt tension at 190 ° C. of 2 to 30 cN

This invention is a polyethylene resin composition for hollow molding containing said aliphatic polyester (A), a component (B), and a component (C).
In the present invention, the “hollow molding polyethylene resin composition” may be simply referred to as “resin composition”.
[Resin composition]
<Component (A): Aliphatic polyester>
The aliphatic polyester (A) in the present invention is a homopolymer or copolymer having a linear or branched alkylene structure bonded by an ester structure as a repeating unit. Examples of the aliphatic polyester (A) include polyesters obtained by polymerizing hydroxycarboxylic acids and polyesters obtained by copolymerizing diols and dicarboxylic acids. You may use these individually or in combination of 2 or more types.
In the present specification, the aliphatic polyester (A) is sometimes referred to as component (A).
Examples of the polyester obtained by polymerizing hydroxycarboxylic acid include a polymer having a repeating unit derived from 3-hydroxyalkanoate represented by the formula (1).

[In the formula, R ₁ Is a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and R ₂ Is a single bond or an alkylene group having 1 to 4 carbon atoms]
The polymer having a repeating unit represented by the formula (1) may be a homopolymer or a multi-component copolymer containing two or more of the above repeating units. The multi-component copolymer may be any of a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, and the like.
Examples of the homopolymer include lactic acid homopolymer, polycaprolactone, poly (3-hydroxybutyrate), poly (4-hydroxybutyrate), poly (3-hydroxypropionate), and the like. Multi-component copolymers include 3-hydroxybutyrate-3-hydroxypropionate copolymer, 3-hydroxybutyrate-4-hydroxybutyrate copolymer, 3-hydroxybutyrate-3-hydroxyvalerate copolymer. Polymer, 3-hydroxybutyrate-3-hydroxyhexanoate copolymer, 3-hydroxybutyrate-3-hydroxyoctanoate copolymer, 3-hydroxybutyrate-3-hydroxyvalerate-3-hydroxy Examples include hexanoate-4-hydroxybutyrate copolymer and 3-hydroxybutyrate-lactic acid copolymer. Among these, it is preferable to use polylactic acid, poly-3-hydroxybutyric acid ester, or a mixture thereof.
Aliphatic polyesters obtained by copolymerizing diols and dicarboxylic acids include polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, butylene succinate-butylene adipate copolymer, butylene succinate-butylene terephthalate copolymer. Examples thereof include a polymer, butylene adipate-butylene terephthalate copolymer, and ethylene succinate-ethylene terephthalate copolymer.
It is preferable to use polylactic acid as the aliphatic polyester (A). The polylactic acid in the present invention is a polymer consisting only of repeating units derived from L-lactic acid and / or D-lactic acid, a repeating unit derived from L-lactic acid and / or D-lactic acid, L-lactic acid and D-lactic acid. A copolymer comprising repeating units derived from monomers other than lactic acid, or a mixture of the polymer and the copolymer. Examples of monomers other than the L-lactic acid and D-lactic acid include hydroxycarboxylic acids such as glycolic acid, aliphatic polyhydric alcohols such as butanediol, and aliphatic polycarboxylic acids such as succinic acid.
The content of the repeating unit derived from L lactic acid or D lactic acid in the polylactic acid is preferably 80 mol% or more, more preferably 90 mol% or more, from the viewpoint of enhancing the heat resistance of the obtained molded article. Preferably it is 95 mol% or more. The melt flow rate (MFR) of the polylactic acid is preferably 1 g / 10 minutes or more, more preferably 2 g / 10 minutes or more, further preferably 3 g / 10 minutes or more from the viewpoint of the fluidity of the resin composition. Yes, even more preferably 5 g / 10 min or more, most preferably 10 g / 10 min or more. Moreover, from a viewpoint of the intensity | strength of a molded object, it is 20 g / 10min or less, More preferably, it is 18 g / 10min or less, More preferably, it is 15 g / 10min or less. MFR is measured by method A under the conditions of a load of 21.18 N and a temperature of 190 ° C. in the method specified in JIS K7210-1995.
<Component (B): Ethylene-α-olefin copolymer>
Component (B) in the present invention is an ethylene-α-olefin copolymer in which the content of repeating units derived from ethylene is 50% by mass or more and less than 100% by mass (provided that ethylene-α-olefin copolymer is used). The total mass is 100% by mass). Hereinafter, it may be called a component (B) or a copolymer (B).
The copolymer (B) is obtained by copolymerizing ethylene and one or more α-olefins having 3 to 12 carbon atoms. Examples of the α-olefin having 3 to 12 carbon atoms include propylene, 1-butene, 1-pentene, 4-methylpentene-1, 1-hexene, 1-octene and 1-decene. Among these, it is preferable to use propylene, 1-butene, 1-hexene, and 1-octene, and it is more preferable to use 1-butene and 1-hexene.
Examples of the copolymer (B) include an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-4-methylpentene-1 copolymer, an ethylene-1-hexene copolymer, and an ethylene- Examples thereof include 1-octene copolymer and ethylene-propylene-1-butene copolymer. Among these, an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, or an ethylene-1-octene copolymer is preferable, and an ethylene-1-butene copolymer, ethylene A -1-hexene copolymer or an ethylene-1-butene-1-hexene copolymer is more preferable.
In addition, the component (B) used by this invention is a repeating unit derived from another monomer in the range which does not impair the effect of this invention in addition to the repeating unit derived from ethylene and the repeating unit derived from alpha-olefin. You may have a unit. Examples of the other monomer include conjugated dienes (for example, butadiene and isoprene), non-conjugated dienes (for example, 1,4-pentadiene), and cyclic olefins (for example, norbornadiene).
The density of the copolymer (B) is 880 to 965 kg / m. ³ It is. Since a hollow molded article having a high impact strength is obtained, the density is preferably 950 kg / m. ³ Or less, more preferably 935 kg / m ³ It is as follows. Since a hollow molded body with high buckling strength can be obtained, the density is preferably 900 kg / m. ³ Or more, more preferably 910 kg / m ³ That's it. The density of a component (B) is measured in accordance with the method prescribed | regulated to A method among JISK7112-1980, after performing annealing as described in JISK6760-1995. Moreover, the density of a copolymer (B) can be changed with content of the monomer unit based on ethylene in a copolymer (B).
The melt flow rate (MFR) of the copolymer (B) is 0.01 to 5 g / 10 min. From the viewpoint of reducing the extrusion load during the molding process, it is preferably 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more. Since a hollow molded article having high impact strength is obtained, the MFR is preferably 2 g / 10 min or less, more preferably 1 g / 10 min or less. In addition, the melt flow rate here is a value measured by the method A under the conditions of a temperature of 190 ° C. and a load of 21.18 N in the method defined in JIS K7210-1995.
The melt flow rate of the copolymer (B) can be changed by, for example, the hydrogen concentration or the polymerization temperature in the method for producing the copolymer (B) described later. When the hydrogen concentration or the polymerization temperature is increased, a copolymer (B) having a high melt flow rate is obtained.
The melt flow rate ratio of the copolymer (B) (hereinafter sometimes referred to as “MFRR”) is preferably 30 or more, more preferably from the viewpoint of further reducing the extrusion load during hollow molding. 50 or more, more preferably 70 or more. Since a hollow molded article having high impact strength is obtained, the MFRR is preferably 200 or less, more preferably 150 or less. The MFRR is a method defined in JIS K7210-1995, wherein a melt flow rate measured under conditions of a load of 211.82 N and a temperature of 190 ° C. It is the value divided by the melt flow rate measured under the condition of 190 ° C.
MFRR can be changed by, for example, the hydrogen concentration in the method for producing a copolymer (B) described later. When the hydrogen concentration is increased, a copolymer (B) having a small MFRR is obtained.
The melt tension at 190 ° C. of the copolymer (B) (hereinafter sometimes referred to as “MT190”) is 2 to 30 cN or more. When the melt tension is less than 1 cN, the shape retention of the parison decreases during hollow molding, and thus the thickness distribution of the molded product increases, and the rigidity of the thin portion decreases, and the buckling strength may decrease. The melt tension is preferably 4 cN or more, more preferably 6 cN or more. The melt tension is preferably 30 cN or less, more preferably 25 cN or less, and even more preferably 20 cN or less from the viewpoint of enhancing the take-up property of the parison during hollow molding.
The melt tension in the present invention refers to the extrusion of the molten copolymer (B) through an orifice having a diameter of 2.095 mm and a length of 8 mm at an extrusion speed of 0.32 g / min at 190 ° C. In the tension when the copolymer (B) is drawn into a filament at a take-up rate of 6.3 (m / min) / min, from the start of take-up until the filament-shaped copolymer (B) is cut. The maximum tension between.
Melt tension can be adjusted with the pressure of the ethylene in superposition | polymerization in the manufacturing method of the copolymer (B) mentioned later. When the pressure of ethylene during polymerization is lowered, a copolymer (B) having a high melt tension is obtained. Moreover, a copolymer (B) with high melt tension can be obtained also by implementing prepolymerization on appropriate conditions.
Ratio of weight average molecular weight (hereinafter sometimes referred to as “Mw”) to number average molecular weight (hereinafter sometimes referred to as “Mn”) of the copolymer (B) (hereinafter referred to as “Mw / Mn ”is sometimes described as 5 to 25. If Mw / Mn is too small, the resin pressure and the resin temperature during molding may increase. Mw / Mn is more preferably 7 or more, and still more preferably 8 or more. Mw / Mn is more preferably 20 or less, and even more preferably 15 or less.
Mw / Mn is a value obtained by measuring Mw and Mn of the copolymer (B) by gel permeation chromatography (GPC) method and dividing Mw by Mn. As measurement conditions in the GPC method, for example, the following conditions can be given.
(1) Apparatus: Waters 150C manufactured by Waters
(2) Separation column: TOSOH TSKgelGMH6-HT
(3) Measurement temperature: 140 ° C
(4) Carrier: Orthodichlorobenzene
(5) Flow rate: 1.0 mL / min
(6) Injection volume: 500 μL
(7) Detector: differential refractometer
(8) Molecular weight reference material: Standard polystyrene
The flow activation energy (Ea) of the copolymer (B) is preferably 45 to 150 kJ / mol. From the viewpoint of increasing the melt tension of the copolymer (B), the viewpoint of improving the buckling strength of the hollow molded body, and the viewpoint of reducing the extrusion load during the molding process, Ea is preferably 55 kJ / mol or more, and more Preferably it is 65 kJ / mol or more. Further, from the viewpoint of enhancing the take-up property at the time of hollow molding, Ea is more preferably 120 kJ / mol or less, further preferably 100 kJ / mol or less, still more preferably 95 kJ / mol or less, most preferably 80 kJ. / Mol or less.
Ea is a shift factor (a for creating a master curve indicating the dependence of the melt complex viscosity (unit: Pa · sec) at 190 ° C. on the angular frequency (unit: rad / sec). _T ), A numerical value calculated by the Arrhenius type equation and obtained by the method shown below.
That is, the melt complex viscosity-angular frequency curve of the copolymer (B) at temperatures of 130 ° C., 150 ° C., 170 ° C. and 190 ° C. (unit: ° C.) is calculated based on the temperature-time superposition principle. The shift factor at each temperature obtained when superposed on the melt complex viscosity-angular frequency curve of the olefin polymer at _T ) From each temperature and the shift factor at each temperature, [ln (a _T )] And [1 / (T + 273.16)] are calculated. Next, Ea is obtained from the slope m of the linear expression and the following expression (II).
ln (a _T ) = M (1 / (T + 273.16)) + n (I)
Ea = | 0.008314 × m | (II)
a _T : Shift factor
Ea: activation energy of flow (unit: kJ / mol)
T: Temperature (unit: ° C)
For the calculation, commercially available calculation software may be used. As the calculation software, Rheos V. manufactured by Rheometrics is used. 4.4.4 etc. are mentioned.
The shift factor is obtained by moving the logarithmic curve of melt complex viscosity-angular frequency at each temperature in the log (Y) =-log (X) axis direction (provided that the Y axis is the melt complex viscosity, the X axis Is an angular frequency.), And a movement amount when superimposed on a melt complex viscosity-angular frequency curve at 190 ° C. In this superposition, the logarithmic curve of melt complex viscosity-angular frequency at each temperature shows the angular frequency as a _T Double the melt complex viscosity to 1 / a _T Move twice. Moreover, the correlation coefficient when calculating | requiring (I) Formula by the least squares method from the value of 4 points | pieces, 130 degreeC, 150 degreeC, 170 degreeC, and 190 degreeC is usually 0.99 or more.
The melt complex viscosity-angular frequency curve is preferably measured using a viscoelasticity measuring device (for example, Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics).
The zero shear viscosity (η of the copolymer (B) at 190 ° C. ₀ ) Is preferably 10 to 300 kPa · sec or more. η ₀ Is preferably 30 kPa · sec or more, and more preferably 50 kPa · sec or more, from the viewpoint of increasing impact strength. From the viewpoint of reducing the extrusion load during molding, η ₀ Is more preferably 200 Pa · sec or less, and still more preferably 100 Pa · sec or less.
η ₀ Is obtained by approximating the master curve of the complex shear viscosity (η) and the angular frequency (ω) obtained when Ea is calculated with the following cross approximation formula.
Approximate expression of cross ... η = η ₀ ÷ [1+ (τ × ω) ⁿ ]
[Where η ₀ , Τ, and n are zero shear viscosity, characteristic relaxation time, and non-Newtonian index, respectively, which are constants determined for each copolymer (B) used for measurement. ]
Examples of the method for producing the copolymer (B) include a solid particulate promoter component in which a promoter component such as an organoaluminum compound, an organoaluminum oxy compound, a boron compound, and an organozinc compound is supported on a particulate carrier. A metallocene complex having a ligand having a structure in which two cyclopentadienyl type anion skeletons are bonded to each other by a bridging group such as an alkylene group or a silylene group, and ethylene and an α-olefin in the presence of a polymerization catalyst. The method of copolymerizing is mentioned.
The polymerization method is preferably a continuous polymerization method involving the formation of ethylene-α-olefin copolymer particles, for example, continuous gas phase polymerization, continuous slurry polymerization, continuous bulk polymerization, preferably continuous gas phase Polymerization. The gas phase polymerization reaction apparatus is usually an apparatus having a fluidized bed type reaction tank, and preferably an apparatus having a fluidized bed type reaction tank having an enlarged portion.
A stirring blade may be installed in the reaction vessel.
As a method of supplying each component of the polymerization catalyst used for the production of the copolymer (B) to the reaction vessel, it is usually in an inert gas such as nitrogen and argon, hydrogen, ethylene, etc., in a state free from moisture. A supplying method and a method in which each component is dissolved or diluted in a solvent and supplied in a solution or slurry state are used. Each component of the polymerization catalyst may be supplied individually, or arbitrary components may be supplied in contact in advance in any order.
Moreover, it is preferable to carry out prepolymerization before carrying out the main polymerization and to use the prepolymerized prepolymerized catalyst component as a catalyst component or catalyst for the main polymerization. Different α-olefins may be used in the main polymerization and the prepolymerization, and it is preferable to prepolymerize an α-olefin having 4 to 12 carbon atoms and ethylene, and an α-olefin having 6 to 8 carbon atoms and ethylene. Is more preferably prepolymerized.
The polymerization temperature is usually lower than the temperature at which the copolymer (B) melts, preferably 0 to 150 ° C, more preferably 30 to 100 ° C, and further preferably 50 to 90 ° C. In order to obtain a copolymer (B) having a wide molecular weight distribution, a higher polymerization temperature is preferred.
The polymerization time (average residence time in the case of continuous polymerization reaction) is usually 1 to 20 hours. In order to obtain a copolymer (B) having a wide molecular weight distribution, a longer polymerization time (average residence time) is preferable.
For the purpose of adjusting the melt flow rate of the copolymer (B), hydrogen may be added to the polymerization reaction gas as a molecular weight regulator, or an inert gas may be allowed to coexist in the polymerization reaction gas. The molar concentration of hydrogen in the polymerization reaction gas with respect to the molar concentration of ethylene in the polymerization reaction gas is usually 0.1 to 3 mol%, assuming that the molar concentration of ethylene in the polymerization reaction gas is 100 mol%. In order to obtain a copolymer (B) having a wide molecular weight distribution, it is preferable that the molar concentration of hydrogen in the polymerization reaction gas is high.
<Component (C): Compatibilizer>
In the present invention, the component (C) is a compatibilizing agent capable of compatibilizing the component (A) and the component (B). Examples of the compatibilizer include a polymer having an epoxy group, a styrene-based thermoplastic elastomer, an ethylene-vinyl acetate copolymer, and an ethylene- (meth) acrylate copolymer. The component (C) is preferably a polymer having an epoxy group.
Whether a certain compound corresponds to the component (C) in the present invention is determined by the following method. Hereinafter, a certain compound is referred to as component (X).
First, a resin composition (1) is obtained by melt-kneading a mixture (1) obtained by mixing a predetermined amount of component (A), component (B) and component (X). Using this resin composition (1), a molded body (1) having a predetermined size is produced.
Next, a molded body (2) having the same size as the molded body (1) is manufactured using the component (B) under the same conditions as the conditions for manufacturing the molded body (1).
The impact strength of the molded body (1) and the impact strength of the molded body (2) are measured. When the impact strength of the molded body (1) exceeds 20% of the impact strength of the molded body (2), the component (X) is the component (C) of the present invention, that is, the component (A) and the component (B). It is a compatibilizer.
Examples of the polymer having an epoxy group include a copolymer having a repeating unit derived from ethylene and a repeating unit derived from a monomer having an epoxy group. Examples of the monomer having an epoxy group include α, β-unsaturated glycidyl ethers such as α, β-unsaturated glycidyl esters such as glycidyl methacrylate and glycidyl acrylate, allyl glycidyl ether, and 2-methylallyl glycidyl ether. Preferably, it is glycidyl methacrylate.
Examples of the polymer having an epoxy group include glycidyl methacrylate-ethylene copolymer (for example, trade name Bond First manufactured by Sumitomo Chemical Co., Ltd.), glycidyl methacrylate-styrene copolymer, glycidyl methacrylate-acrylonitrile-styrene copolymer, and glycidyl. And methacrylate-propylene copolymer. Further, a monomer having an epoxy group was graft-polymerized by solution or melt-kneading to polyethylene, polypropylene, polystyrene, ethylene-α-olefin copolymer, hydrogenated and non-hydrogenated styrene-conjugated diene systems, and the like. A polymer may be used.
In the polymer having an epoxy group, the content of the repeating unit derived from the monomer having an epoxy group is 0.01% by mass to 30% by mass, preferably 0.1% by mass to 20% by mass. More preferably, it is 5% by mass to 15% by mass, further preferably 8% by mass to 15% by mass, and still more preferably 10% by mass to 20% by mass (provided that a polymer having an epoxy group is used). 100 mass%). In addition, content of the repeating unit derived from the monomer which has an epoxy group is measured by the infrared method. Specifically, first, a polymer having an epoxy group is pressed to prepare a sheet. Next, the infrared absorption spectrum of the sheet is measured. The absorbance of the characteristic absorption of the infrared absorption spectrum is corrected by the thickness of the sheet, and the content is obtained by a calibration curve method. As glycidyl methacrylate characteristic absorption, 910cm ^-1 The peak of is used.
The melt flow rate (MFR) of the polymer having an epoxy group is 1 g / 10 min to 15 g / 10 min. From the viewpoint of workability, the MFR is preferably 1.5 g / 10 min or more, more preferably 2 g / 10 min or more. From the viewpoint of easy reaction between the polymer having an epoxy group and other components, the MFR is preferably 8 g / 10 min or less, more preferably 7 g / 10 min or less, and further preferably 5 g / 10 min. Min or less, and even more preferably 4 g / 10 min or less. The melt flow rate here is a value measured under the conditions of a test load of 21.18 N and a test temperature of 190 ° C. by the method defined in JIS K 7210 (1995).
Examples of the method for producing a polymer having an epoxy group include a method of copolymerizing a monomer having an epoxy group with another monomer by a high-pressure radical polymerization method, a solution polymerization method, an emulsion polymerization method, and the like. Examples thereof include a method in which a monomer having an epoxy group is graft polymerized to a resin based resin.
The polymer having an epoxy group may have a repeating unit derived from another monomer. Examples of other repeating units include unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and butyl acrylate, and unsaturated vinyl esters such as vinyl acetate and vinyl propionate.
As the component (C), a styrenic thermoplastic elastomer can also be used. Specific examples of the styrene-based thermoplastic elastomer include styrene-butadiene rubber (SBR) or a hydrogenated product thereof (H-SBR), a styrene-butadiene block copolymer (SBS) or a hydrogenated product thereof (SEBS), styrene- Isoprene block copolymer (SIS) or its hydrogenated product (SEPS, HV-SIS), styrene- (butadiene / isoprene) block copolymer, styrene- (butadiene / isoprene) random copolymer, and the like.
An ethylene-vinyl acetate copolymer can also be used as the component (C). Examples of ethylene-vinyl acetate copolymer products include Mitsui DuPont Polychemical's "Evaflex", LANXESS's "Revaprene", Sumitomo Chemical's "Evaate", Tosoh "Ultrasen", Nippon Polyethylene "Novatec" Nippon Unicar “NUC EVA copolymer” and the like can be mentioned.
An ethylene- (meth) acrylic acid ester copolymer can also be used as the component (C). Examples of ethylene- (meth) acrylic acid ester copolymers include “Lotril” manufactured by Arkema, “Evaflex EEA” manufactured by Mitsui DuPont Polychemical, “Aklift” manufactured by Sumitomo Chemical, and “UNUC EEA Copolymer” manufactured by Nihon Unicar. Etc.
The content of each component in the resin composition of the present invention is such that the total amount of the components (A), (B) and (C) contained in the resin composition is 100% by mass, and the content of the component (A) is The content of component (B) is 50 to 94% by mass, and the content of component (C) is 1 to 15% by mass. Preferably, the content of component (A) is 10 to 45% by mass, the content of component (B) is 53 to 88% by mass, and the content of component (C) is 2 to 12% by mass. More preferably, the content of the component (A) is 20 to 42% by mass, the content of the component (B) is 55 to 77% by mass, and the content of the component (C) is 3 to 10% by mass. It is. By setting the blending ratio of each component in the above range, it is possible to obtain a hollow molded body having high buckling strength and high impact strength.
From the viewpoint of heat fusion strength between parisons during hollow molding, the value obtained by dividing the mass of the component (A) in the resin composition by the mass of the component (C) is preferably less than 10, and is 8 or less. More preferably, it is more preferably 6 or less, still more preferably 5 or less, and most preferably 4 or less.
For the resin composition, if necessary, an antioxidant, a neutralizing agent, a lubricant, an antistatic agent, a nucleating agent, an ultraviolet ray preventing agent, a plasticizer, a dispersing agent, an antifogging agent, an antibacterial agent, and an organic porous powder It is possible to add additives such as pigments.
Various resin components may be added to the resin composition as long as the effects of the present invention are not impaired. Examples of the various resin components include ethylene-α-olefin copolymers that do not fall under the component (B) of the present invention, HDPE, high-pressure low-density polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 66, Nylon 11, Nylon 12, Nylon 6, 66, Styrenic thermoplastic elastomer, olefinic thermoplastic elastomer, polyester thermoplastic elastomer, polyurethane thermoplastic elastomer, polyamide thermoplastic elastomer not applicable as component (C) Etc.
The manufacturing method of a resin composition is not specifically limited, A well-known blend method can be used. Examples of known blending methods include a method of dry blending or melt blending the components (A) to (C) and other components such as additives as necessary. Examples of the dry blending method include a method using various blenders such as a Henschel mixer and a tumbler mixer. Examples of the melt blending method include a single screw extruder, a twin screw extruder, a Banbury mixer, a hot roll, and the like. The method of using various mixers is mentioned.
[Method for producing hollow molded body]
Examples of the hollow molding method include an extrusion method, an accumulator method, a hot parison method, a cold parison method, and an injection method. For example, the hollow molded body of the present invention is obtained by extruding a molten resin composition from an extruder to obtain a molten parison, setting the parison in a mold having a desired shape of the hollow molding machine, and then compressing the compressed gas. Is blown to the inner wall of the mold and then cooled. In addition, examples of the molding mechanism of the molding machine include a shuttle type, a rotary type, and a satellite type, and examples of the mold clamping method include a hydraulic type, an electric type, and a toggle type. You may extend | stretch at the time of shaping | molding.
The hollow molded body thus obtained is used for tubes, bottles, tanks and the like. The hollow molded article is suitably used for food containers, industrial use, medical use, daily necessities and the like.
The resin composition of the present invention may be used when producing a single-layer hollow molded article, and when producing a multilayer hollow molded article, it is used for forming one layer contained in the multilayer hollow molded article. Also good. As a layer other than the layer made of the resin fat composition of the present invention contained in the multilayer hollow molded body, a layer having excellent slipperiness, a barrier layer of gas such as oxygen or water vapor, a light shielding layer, an oxygen absorbing layer, an adhesive layer , A colored layer, a conductive layer, a recycled resin-containing layer, and the like.
Examples of the resin constituting the layer other than the layer using the resin composition of the present invention include, for example, high density polyethylene, low density polyethylene, very low density polyethylene, ultra low density polyethylene, polypropylene, and ethylene-vinyl acetate copolymer. , Ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer Saponified product, ethylene-styrene copolymer, ethylene-vinylcyclohexane copolymer, ethylene-norbornene copolymer, polyolefin rubber, styrene-butadiene rubber, styrene-butadiene-styrene block copolymer, isoprene rubber, styrene-isoprene rubber , Isobutylene rubber Acid modified products or hydrogenated products thereof and the like resins and.

EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these Examples. The physical properties were evaluated by the following methods.
(1) Density (Unit: kg / m ³ )
Using a sheet having a thickness of 1 mm obtained by pressing the component (B) at 150 ° C., the density was measured according to JIS K 6760 (1981). The sample used for the measurement was subjected to annealing described in JIS K6760-1995.
(2) Melt flow rate (MFR, unit: g / 10 minutes)
The melt flow rate of the component (B) was measured according to JIS K 7210 (1995) under conditions of a test load of 21.18 N and a test temperature of 190 ° C.
(3) Melt flow rate ratio (MFRR)
The melt flow rate ratio of component (B) is the same as the melt flow rate (H-MFR) measured under the conditions of a test load of 211.82 N and a measurement temperature of 190 ° C. in the method specified in JIS K7210 (1995). In the method defined in K7210 (1995), a melt flow rate (MFR) measured under conditions of a load of 21.18 N and a temperature of 190 ° C. was measured, and a value obtained by dividing H-MFR by MFR was used.
(4) Molecular weight distribution (Mw / Mn)
The molecular weight distribution of the component (B) is determined using the gel permeation chromatograph (GPC) method under the following conditions (1) to (8): weight average molecular weight (Mw) and number average molecular weight (Mn) Was measured and determined.
The baseline on the chromatogram is a stable horizontal region with a sufficiently long retention time than the appearance of the sample elution peak and a stable horizontal region with a sufficiently long retention time than the solvent elution peak was observed. A straight line formed by connecting the points.
(1) Apparatus: Waters 150C manufactured by Waters
(2) Separation column: TOSOH TSKgelGMH6-HT
(3) Measurement temperature: 140 ° C
(4) Carrier: Orthodichlorobenzene (5) Flow rate: 1.0 mL / min (6) Injection volume: 500 μL
(7) Detector: differential refractometer (8) Molecular weight standard: Standard polystyrene (5) Flow activation energy (Ea, unit: kJ / mol)
Ea of component (B) is dynamic viscoelasticity data at each temperature T (K) measured under the following conditions (a) to (d) using a strain-controlled rotary viscometer (rheometer). Arrhenius equation of shift factor (aT) when shifting based on temperature-time superposition principle: log (aT) = Ea / R (1 / T-1 / T0) (R is gas constant, T0 is reference The temperature is 463 K.). Ea is an index of formability. Calculation software includes Rohms V. from Reometrics. 4.4.4 was used, and the Ea value when the correlation coefficient r2 at the time of linear approximation in the Arrhenius type plot log (aT) − (1 / T) was 0.99 or more was adopted. The measurement was performed under nitrogen.
Condition (a) Geometry: Parallel plate, diameter 25 mm, plate interval: 1.5-2 mm
Condition (b) Strain: 5%
Condition (c) Shear rate: 0.1 to 100 rad / sec
Condition (d) Temperature: 190, 170, 150, 130 ° C
(6) Zero shear viscosity at 190 ° C. (η ₀ , unit: Pa · sec)
The master curve of the melt complex viscosity-angular frequency curve at 190 ° C. obtained when the above-described flow activation energy was obtained was calculated using a calculation software Rhios V.R. manufactured by Rheometrics. Using 4.4.4, approximation was performed using the following cross approximation formula, and zero shear viscosity (η ₀ ), characteristic relaxation time (τ), and non-Newtonian index (n) were calculated.
Cross approximate expression η = η ₀ ÷ [1+ (τ × ω) ⁿ ]
(7) 190 ° C. melt tension (MT, unit: cN)
Using a melt tension tester manufactured by Toyo Seiki Seisakusho, the copolymer (B) was melt extruded from an orifice having a diameter of 2.095 mm and a length of 8 mm at a temperature of 190 ° C. and an extrusion speed of 0.32 g / min. The polymer (B) was taken up into a filament shape by a take-up roll at a take-up rate of 6.3 (m / min) / min, and the tension during take-up was measured. The maximum tension from the start of take-up until the filamentous copolymer (B) was cut was defined as the melt tension.
(8) Hollow molding The resin compositions produced in Examples and Comparative Examples were hollow molded with a Tahara MSE-55E / 54M-A (E1) hollow molding machine to produce a 500 ml cylindrical bottle. Using a circular die of 16 mmφ and a circular core of 15 mmφ core, the crosshead temperature of the extruder: 210 ° C., die temperature: 210 ° C., mold temperature: 30 ° C., discharge amount: 8 kg / hr, The opening degree of the die core was adjusted to obtain a hollow molded body having a basis weight of 20 g. The parison control using the molding profile was not performed.
(9) Drop strength The cylindrical bottle obtained by the method of (8) was filled with water, and the cylindrical bottle was capped and sealed. The cylindrical bottle was placed in a 1 ° C. constant temperature bath for 12 hours or more to adjust the state. After the state adjustment, the cylindrical bottle was dropped (vertically dropped) at a room temperature from a height of 1 m with the cap portion facing up. When pinholes and cracks did not occur in the cylindrical bottle, the cylindrical bottle was dropped (laterally dropped) with the cap portion turned sideways. Until a pinhole or a crack occurs in the cylindrical bottle, the vertical drop and the horizontal drop are alternately repeated up to 10 times each (20 times in total for the vertical drop and the horizontal drop) until the cylindrical bottle is subjected to a drop test.
By this drop test, the number of drops until pinholes or cracks occur in the cylindrical bottle, that is, n-1 is obtained for five cylindrical bottles when pinholes or cracks occur in the cylindrical bottle at the nth time, The total number of drops of the five cylindrical bottles was determined as a drop strength index. However, it was set to 20 when pinholes and cracks did not occur in the cylindrical bottle even after 20 drops. If all five pieces are not broken by 20 drops, (drop strength index) = 100, and if all 5 pieces are broken by the first drop, (drop strength index) = 0. The higher the drop strength index, the higher the impact resistance.
The case where the drop strength index was 0 or more and 33 or less was determined as “drop strength: x”, and the case where it was 34 or more and 66 or less was determined as “drop strength: Δ” 67 or more and 100 or less as “drop strength: ◯”.
(10) Buckling strength (Unit: N)
The test was conducted using a tensile tester equipped with a jig for compression test. A cylindrical bottle without a cap was placed on a 100 mmφ metal disk installed instead of the lower chuck. A 60 mmφ metal disc installed instead of the upper chuck was lowered at a speed of 20 mm / min, and the cylindrical bottle was compressed and buckled. The maximum load at this time was defined as the buckling strength.
When the buckling strength is 0 or more and less than 50, “buckling strength: ×”, when 50 or more and less than 70, “buckling strength Δ”, and when 70 or more and less than 90, “buckling strength: ○”. , 90 or more was defined as "buckling strength: A".
Each component used in the examples of the present invention is as follows.
<Component (A): Polylactic acid>
Unitika Co., Ltd., trade name “Terramac TE-2000C”, MFR (190 ° C.) = 12 g / 10 min, lactic acid homopolymer <component (B): ethylene-α-olefin copolymer>
[Polymerization Example 1: (B-1) Production of ethylene-1-hexene copolymer]
(1) Preparation of catalyst solid component (a) Silica heated by a reactor equipped with a nitrogen-replaced stirrer at 300 ° C. under a flow of nitrogen (Sypolol 948 manufactured by Devison; 50% volume average particle size = 55 μm; (Pore volume = 1.67 ml / g; specific surface area = 325 m ² / g) 2.8 kg and 24 kg of toluene were added and stirred. After cooling to 5 ° C., a mixed solution of 0.9 kg of 1,1,1,3,3,3-hexamethyldisilazane and 1.4 kg of toluene was added while maintaining the reactor temperature at 5 ° C. Dropped in minutes. After completion of the dropwise addition, the mixture was stirred at 5 ° C. for 1 hour, then heated to 95 ° C., stirred at 95 ° C. for 3 hours, and filtered. The obtained solid product was washed 6 times with 20.8 kg of toluene. Thereafter, 7.1 kg of toluene was added to the washed solid product to form a slurry, and the slurry was allowed to stand overnight.
To the slurry obtained above, 1.73 kg of diethylzinc in hexane (diethylzinc concentration: 50 mass%) and 1.02 kg of hexane were added and stirred. Then, after cooling the mixture to 5 ° C., a mixed solution of 0.78 kg of 3,4,5-trifluorophenol and 1.44 kg of toluene was added dropwise over 60 minutes while keeping the temperature of the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour, heated to 40 ° C., and stirred at 40 ° C. for 1 hour.
Thereafter, the mixture was cooled to 22 ° C., and 0.11 kg of water was added dropwise while keeping the temperature of the reactor at 22 ° C. After completion of dropping, the mixture was stirred for 1.5 hours while maintaining the temperature at 22 ° C. Next, this was heated up to 40 degreeC, and it stirred at 40 degreeC for 2 hours, and also heated up at 80 degreeC, and stirred at 80 degreeC for 2 hours.
After stirring, the supernatant was withdrawn to a residual amount of 16 L at room temperature, charged with 11.6 kg of toluene, then heated to 95 ° C. and stirred for 4 hours. After stirring, the supernatant liquid was extracted at room temperature to obtain a solid product. The obtained solid product was washed 4 times with 20.8 kg of toluene and 3 times with 24 L of hexane. Thereafter, the washed solid product was dried to obtain a solid component for catalyst (a).
(2) Preparation of prepolymerization catalyst component After adding 80 L of butane to an autoclave with a stirrer having an internal volume of 210 L previously purged with nitrogen, 34.5 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide was added, and the autoclave The mixture was heated to 50 ° C. and stirred for 2 hours. Next, after the temperature of the autoclave was lowered to 30 ° C. and the system was stabilized, ethylene was charged so that the ethylene partial pressure in the autoclave was 0.03 MPa, and the solid component for catalyst (a) 0. 7 kg was charged, and then 140 mmol of triisobutylaluminum was charged to initiate polymerization.
After 30 minutes while ethylene was continuously supplied at 0.7 kg / Hr, the autoclave was heated to 50 ° C., and ethylene and hydrogen were 3.5 kg / Hr and 10.2 L (room temperature and normal pressure volume) / Hr, respectively. For a total of 4 hours of prepolymerization. After the polymerization was completed, ethylene, butane, hydrogen gas and the like were purged, and the remaining solid was vacuum dried at room temperature to obtain a prepolymerized catalyst component in which 15 g of polyethylene was prepolymerized per 1 g of the catalyst solid component (a). .
(3) Production of ethylene-1-hexene copolymer Using the prepolymerization catalyst component obtained in (2) above, copolymerization of ethylene and 1-hexene was carried out in a continuous fluidized bed gas phase polymerization apparatus, I got a powder. As polymerization conditions, the polymerization temperature was 80 ° C., the polymerization pressure was 2 MPa, the hydrogen molar ratio to ethylene was 1.6%, and the 1-hexene molar ratio to ethylene was 0.9%.
During the polymerization, ethylene, 1-hexene and hydrogen were continuously supplied in order to keep the gas composition constant. In addition, the prepolymerization catalyst component and triisobutylaluminum were continuously supplied, and the total powder mass of 80 kg in the fluidized bed was kept constant. The average polymerization time was 4 hours. The obtained polymer powder is fed using an extruder (LCM50 manufactured by Kobe Steel, Ltd.) at a feed rate of 50 kg / hr, a screw speed of 450 rpm, a gate opening of 50%, a suction pressure of 0.2 MPa, and a resin temperature of 200 to 230. An ethylene-1-hexene copolymer was obtained by granulation under the condition of ° C. Table 1 shows the results of the physical property evaluation of the obtained copolymer.
[Polymerization Example 2: (B-2) Production of ethylene-1-hexene copolymer]
(1) Preparation of prepolymerization catalyst component In an autoclave with a stirrer having an internal volume of 210 L, which was previously purged with nitrogen, 0.7 kg of the solid component for catalyst (a) described in (1) of Polymerization Example 1, 80 L of butane, room temperature After charging 0.1 L of atmospheric hydrogen, the autoclave was raised to 30 ° C. Furthermore, ethylene and the ethylene partial pressure in the autoclave were charged so that the system became 0.03 MPa. After the system was stabilized, 140 mmol of triisobutylaluminum and 88 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide were added to perform polymerization. Started.
While raising the temperature of the autoclave to 50 ° C. and continuously supplying ethylene and hydrogen, prepolymerization was carried out at 50 ° C. for a total of 6 hours. After the polymerization was completed, ethylene, butane, hydrogen gas and the like were purged, and the remaining solid was vacuum dried at room temperature to obtain a prepolymerized catalyst component in which 19 g of polyethylene was prepolymerized per 1 g of the catalyst solid component (a). .
(2) Production of ethylene-1-hexene copolymer Ethylene and 1-hexene were copolymerized in a continuous fluidized bed gas phase polymerization apparatus using the above prepolymerization catalyst component. The polymerization conditions were a temperature of 82 ° C., a total pressure of 2 MPa, a gas linear velocity of 0.3 m / s, a hydrogen molar ratio to ethylene of 1.3%, and a 1-hexene molar ratio to ethylene of 2.0%. In order to maintain a constant value, ethylene, hexene-1, and hydrogen were continuously supplied. Further, the pre-polymerization catalyst component and triisobutylaluminum were continuously supplied at a constant ratio so that the total powder weight of the fluidized bed was maintained at 80 kg and the average polymerization time was 3 hours. By polymerization, a powder of ethylene-1-hexene copolymer was obtained with a production efficiency of 21 kg / hr.
The obtained ethylene-1-hexene copolymer powder was fed with a feed rate of 50 kg / hr, a screw rotation speed of 450 rpm, a gate opening of 4.2 mm, and a suction pressure of 0.2 MPa using an LCM50 extruder manufactured by Kobe Steel. Then, an ethylene-1-hexene copolymer was obtained by granulating at a resin temperature of 200 to 230 ° C. Table 1 shows the results of the physical property evaluation of the obtained copolymer.
[Polymerization Example 3: (B-3) Production of ethylene-1-hexene copolymer]
(1) Preparation of prepolymerization catalyst component In an autoclave with a stirrer having an internal volume of 210 L, which was previously purged with nitrogen, 0.7 kg of the solid component for catalyst (a) described in (1) of Polymerization Example 1, 80 L of butane, room temperature After charging 0.1 L as atmospheric hydrogen, the autoclave was raised to 35 ° C.
Further, ethylene was charged so that the ethylene partial pressure in the autoclave was 0.03 MPa, and after the system was stabilized, 350 mmol of triisobutylaluminum and 88 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide were added for polymerization. Started. While raising the temperature of the autoclave to 50 ° C. and supplying ethylene and hydrogen continuously, prepolymerization was carried out at 50 ° C. for a total of 6 hours.
After completion of the polymerization, purging with ethylene, butane, hydrogen gas, etc., the remaining solid is vacuum dried at room temperature to obtain a prepolymerized catalyst component in which 22 g of polyethylene is prepolymerized per 1 g of the catalyst solid component (a). It was.
(2) Production of ethylene-1-hexene copolymer Ethylene and 1-hexene were copolymerized in a continuous fluidized bed gas phase polymerization apparatus using the above prepolymerization catalyst component. The polymerization conditions were a temperature of 86 ° C., a total pressure of 2 MPa, a gas linear velocity of 0.3 m / s, a hydrogen molar ratio to ethylene of 0.9%, and a 1-hexene molar ratio to ethylene of 1.1%. In order to maintain a constant value, ethylene, hexene-1, and hydrogen were continuously supplied. Further, the pre-polymerization catalyst component and triisobutylaluminum were continuously supplied at a constant ratio so that the total powder weight of the fluidized bed was maintained at 80 kg and the average polymerization time was 5.5 hr. By polymerization, a powder of an ethylene-1-hexene copolymer was obtained with a production efficiency of 15 kg / hr.
The obtained ethylene-1-hexene copolymer powder was fed with a feed rate of 50 kg / hr, a screw rotation speed of 450 rpm, a gate opening of 4.2 mm, and a suction pressure of 0.2 MPa using an LCM50 extruder manufactured by Kobe Steel. Then, an ethylene-1-hexene copolymer was obtained by granulating at a resin temperature of 200 to 230 ° C. Table 1 shows the results of the physical property evaluation of the obtained copolymer.
In Example 5, Comparative Example 5 and Comparative Example 6, the following polyethylene was used as component (B).
(B-4): Metallocene catalyst-based linear low-density polyethylene (trade name Sumikasen E FV102 manufactured by Sumitomo Chemical Co., Ltd., physical properties are as shown in Table 1)
(B-5): Metallocene catalyst-based linear low-density polyethylene (trade name Sumikasen E FV205 manufactured by Sumitomo Chemical Co., Ltd., hereinafter referred to as PE-5. Physical properties are shown in Table 1)
(B-6): High-pressure radical polymerization low-density polyethylene (trade name Sumikasen F102-0 manufactured by Sumitomo Chemical Co., Ltd., as shown in Table 1)
<Component (C): Compatibilizer>
C-1: manufactured by Sumitomo Chemical Co., Ltd., trade name “bond first E” (ethylene-glycidyl methacrylate copolymer, MFR (190 ° C.) = 3 g / 10 min, repeating unit content derived from glycidyl methacrylate = 12 mass%)

[Examples 1 to 5 and Comparative Examples 1 to 6]
Component (A), component (B), and component (C) were mixed together at the composition ratios shown in Tables 2 and 3. The mixture was melt-kneaded at 200 ° C. using a single screw extruder to obtain a resin composition. The resin composition was hollow molded to obtain a 500 ml cylindrical bottle. The physical properties of the obtained hollow molded body are shown in Tables 4 and 5.

According to the present invention, it is possible to provide a resin composition for producing a hollow molded article having excellent buckling strength and impact strength, and a hollow molded article having excellent buckling strength and impact strength.

Claims (5)

1. Polyethylene resin composition for hollow molding containing 5 to 49% by weight of aliphatic polyester (A), 50 to 94% by weight of the following component (B), and 1 to 15% by weight of compatibilizer (C) (however, , The total amount of the aliphatic polyester (A), the component (B) and the component (C) is 100% by mass).
   Component (B): an ethylene-α-olefin copolymer having a density of 880 to 965 kg / m ³ , a melt flow rate of 0.01 to 5 g / 10 min, and a melt tension at 190 ° C. of 2 to 30 cN
2. The polyethylene resin composition for hollow molding according to item 1, wherein the aliphatic polyester (A) is polylactic acid, poly (3-hydroxybutyrate ester), or a mixture thereof.
3. The polyethylene resin composition for hollow molding according to Item 1 or 2, wherein the component (B) is an ethylene-α-olefin copolymer having a flow activation energy (Ea) of 55 to 100 kJ / mol. .
4. The polyethylene-based resin composition for hollow molding according to any one of Items 1 to 3, wherein the component (C) is an ethylene-based resin having an epoxy group.
5. A hollow molded article comprising the polyethylene resin composition for hollow molding according to any one of Items 1 to 4.