JP7065232B2 - Mold - Google Patents

Description

The present invention relates to a composition containing high-pressure low-density polyethylene and a molded product containing the composition.

High-pressure method low-density polyethylene (LDPE) has been widely used as a general-purpose resin, but it is known that it has inferior environmental stress crack resistance (also called stress cracking resistance or ESCR), and is a surfactant solution. There is a problem that it cannot be applied to applications that may come into contact with, etc., or applications that continuously generate stress, and there are restrictions on the applications that can be applied.

On the other hand, it is known that linear low density polyethylene (LLDPE) tends to be superior to ESCR as compared with high pressure method low density polyethylene (LDPE). It is also known that among high-density polyethylene (HDPE), those having a linear molecular structure tend to be superior in ESCR to high-pressure low-density polyethylene (LDPE).

Patent Document 1 discloses that a composition of LDPE and an ethylene-α-olefin copolymer is prepared for the purpose of improving the ESCR of LDPE. In addition, Non-Patent Document 1 refers to the mechanism of developing environmental stress crack resistance of a composition composed of LDPE and an ethylene / vinyl acetate copolymer.

Japanese Unexamined Patent Publication No. 9-111063

Journal of Applied Polymer Science 2014,131m 39880

Due to its unique mechanical strength, LLDPE has a problem that it has a large tensile elongation, that is, it tends to be inferior in tearability or tearability (hereinafter, collectively referred to as tearability) of the molded product. , HDPE and polypropylene have a problem of inferior flexibility.

When an ethylene-α-olefin copolymer such as LLDPE is mixed with LDPE to form a composition, the effect of improving ESCR is observed depending on the compounding ratio, but the tearing property tends to decrease, and the tearing property tends to decrease. It was difficult to achieve good balance of tearability. Further, in the case of the composition disclosed in Non-Patent Document 1 described above, the tearability is unknown, but there is a concern that the mechanical properties, especially the impact strength, may decrease, and the problem of increased product weight due to the increase in specific gravity may occur. There are also concerns about long-term stability and hygiene issues such as hygroscopicity and odor.
An object of the present invention is to provide a composition having excellent stress cracking resistance (ESCR) while maintaining the tearability of high pressure method low density polyethylene (LDPE).

The present inventors have made diligent studies to solve the above problems. As a result, they have found that a composition containing a polymer having a specific composition and physical properties in a specific ratio with respect to high-pressure low-density polyethylene can solve the above-mentioned problems, and have completed the present invention.

The present invention relates to the following [1] to [4].
[1] High-pressure method Low-density polyethylene (A) 70 to 99 parts by mass and polymer (B) 1 to 30 parts by mass satisfying the following requirements (B-1) to (B-3) (however, (A) above And (B) is 100 parts by mass) and the composition (X).
(B-1) The total T of the contents of the 1-butene-derived structural unit (U1), the ethylene-derived structural unit (U2), and the propylene-derived structural unit (U3) is 100 mol%. The U1 content is 5 to 100 mol%.
(B-2) The content of U2 is 40 mol% or less of the total constituent unit amount.
(B-3) The glass transition temperature (Tg) measured by dynamic viscoelasticity measurement is
It is -15 ° C or lower.

[2] The composition (X) according to the above [1], wherein the content of U1 is 50 to 100 mol% in the total T of 100 mol% of the contents of U1 to U3 in the requirement (B-1). ).

[3] The composition (X) according to the above [1], wherein the content of U1 is 5 to 50 mol% in the total T of 100 mol% of the contents of U1 to U3 in the requirement (B-1). ).

[4] A molded product containing the composition (X) according to any one of the above [1] to [3].

According to the present invention, it is possible to provide a composition having excellent stress cracking resistance (ESCR) while maintaining the tearing property of the high pressure method low density polyethylene (LDPE).

Hereinafter, the composition (X) and the molded product of the present invention will be described in detail.
[Composition (X)]
The composition (X) of the present invention comprises 70 to 99 parts by mass of high-pressure low-density polyethylene (A) and 1 to 30 parts by mass of a polymer (B) satisfying the requirements (B-1) to (B-3) described later. Including the part. However, the total of (A) and (B) is 100 parts by mass. Hereinafter, the (A) and (B) are also referred to as “component (A)” and “component (B)”, respectively.

The composition (X) preferably contains the component (A) in the range of 75 to 95 parts by mass and the component (B) in the range of 5 to 25 parts by mass, and more preferably contains the component (A) in an amount of 80 to 95 parts by mass. (B) is contained in the range of 5 to 20 parts by mass, more preferably the component (A) is contained in the range of 80 to 92 parts by mass, and the component (B) is contained in the range of 8 to 20 parts by mass. However, the total of (A) and (B) is 100 parts by mass. Such an embodiment is preferable in that both ESCR and tearability can be achieved at the same time.

The composition (X) may be a polymer other than the components (A) and (B) (hereinafter, "other polymer (C)" or ". It can optionally contain at least one selected from the "component (C)") and the resin additive (hereinafter, also referred to as "additive (D)").

The composition (X) preferably contains the components (A) and (B) in a total amount of 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass. The above is particularly preferably 98% by mass or more. Such an embodiment is preferable in terms of the appearance of the obtained molded product. The upper limit of the total content of the components (A) and (B) may be 100% by mass, but the composition (X) is a component such as another polymer (C) and / or an additive (D). The upper limit is determined by the content of these components.

[High pressure method low density polyethylene (A)]
As the high-pressure method low-density polyethylene (A), known ones can be used without restriction. The high-pressure method low-density polyethylene is generally polyethylene obtained by radical polymerization of ethylene under high temperature and high pressure, and the method for producing the polyethylene is not particularly limited, but is, for example, 500 to 2000 atm and 150 to 300. Examples thereof include a radical polymerization method in which radical polymerization is carried out under the condition of ° C., and examples thereof include organic peroxides as the polymerization initiator.

The density of the component (A) preferably measured according to ASTM D1505 is preferably in the range of 900 to 925 kg / m ³ , and more preferably 910 to 925 kg / m ³ .
The component (A) preferably has a melt flow rate (MFR) in the range of 0.1 to 50 g / 10 minutes measured under the conditions of 190 ° C. and a 2.16 kg load in accordance with ASTM D1238, more preferably. Is 1 to 20 g / 10 minutes.

[Polymer (B)]
The requirements (B-1) to (B-3) satisfied by the polymer (B) will be described. Further, it is preferable that the polymer (B) satisfies the requirements (B-4) and / or (B-5) described later, and these will also be described.

<< Requirements (B-1) >>
The component (B) is 100 mol% of the total content T of the constituent unit (U1) derived from 1-butene, the constituent unit (U2) derived from ethylene, and the constituent unit (U3) derived from propylene. The content of U1 is 5 to 100 mol%.

In one aspect of the component (B), the content of U1 is preferably 50 to 100 mol%, more preferably 70 to 100 mol% in the total T of 100 mol%. Hereinafter, this range is also referred to as a “preferable range (1)”. When the content of U1 is in the above range, a composition (X) having excellent ESCR can be obtained, which results in a sufficient amount of crystals formed of 1-butene, resulting in a molded product having excellent crack propagation resistance. It is thought that this is because.

In another aspect of the component (B), the content of U1 is preferably 5 to 50 mol%, more preferably 5 to 35 mol% in the total T of 100 mol%. Hereinafter, this range is also referred to as a “preferable range (2)”. When the content of U1 is in the above range, a composition (X) having excellent ESCR can be obtained, in which the amount of crystals produced from ethylene or propylene is in an appropriate range, and as a result, molding having excellent crack propagation resistance is obtained. It is thought that this is because it becomes a body. In this case, the content of U3 is preferably 50 to 95 mol%, more preferably 65 to 95 mol% in the total T of 100 mol%.

The content of each structural unit in the component (B) can be adjusted, for example, by the amount of each monomer added during the polymerization reaction. One of ethylene and propylene may be used, or both may be used in combination. The ratio is not particularly limited.

The total content of U1, U2, and U3 is usually 90 mol% or more, preferably 95 mol% or more, and more preferably 98 mol% or more of the total constituent unit amounts constituting the component (B). , Particularly preferably 100 mol%. That is, the component (B) may have a structural unit derived from a monomer other than 1-butene, ethylene, and propylene as long as the effect of the invention is not impaired. Other building blocks include, for example, building blocks derived from α-olefins having 20 or less carbon atoms (excluding 1-butene and propylene). For example, 1-pentene, 1-hexene, 1-octene, 1-decene can be mentioned.

<< Requirements (B-2) >>
The content of U2 of the component (B) is 40 mol% or less, preferably 30 mol% or less of the total constituent unit amount. In such an embodiment, the tearability and ESCR of the obtained composition (X) are excellent. This suppresses the compatibility between the high-pressure method low-density polyethylene (A) and the polymer (B), and as will be described later, a sea-island structure in which the polymer (B) is an island phase is formed in the composition (X). It is thought that this is because it is easy to do.

<< Requirements (B-3) >>
The glass transition temperature (Tg) of the component (B) measured by dynamic viscoelasticity measurement is −15 ° C. or lower, preferably −18 ° C. or lower, and more preferably −20 ° C. or lower. The lower limit is not particularly limited, but is usually −80 ° C. When the glass transition temperature (Tg) is in the above range, the composition (X) having excellent properties of preventing crack propagation can be obtained, which is due to the effect of stress absorption due to the high motility of the molecular chain. it is conceivable that.

The temperature at which the loss elastic modulus (E ″) by the dynamic viscoelasticity measurement shows the maximum value is defined as the glass transition temperature (Tg). The dynamic viscoelasticity measurement is performed by raising the temperature in the temperature range of −90 to 200 ° C. at 3 ° C./min in a nitrogen atmosphere. The strain to be applied is 0.1%, and the frequency is 1 Hz.

The glass transition temperature (Tg) can be adjusted to the above range by adjusting the ratio of U1, U2 and U3. For example, by setting the content of U1 to the preferable range (1) of the above requirement (B-1), Tg tends to be in the above range. Alternatively, by setting the content of U1 to the preferable range (2) of the above requirement (B-1) and setting the content of U2 to the range of the above requirement (B-2), Tg tends to be in the above range.

<< Requirements (B-4) >>
The component (B) preferably has a melt flow rate (MFR) in the range of 0.1 to 100 g / 10 minutes measured under the conditions of 190 ° C. and a 2.16 kg load in accordance with ASTM D1238, more preferably. Is in the range of 0.1-50 g / 10 minutes. In such an embodiment, the component (B) is considered to have a molecular weight sufficient to exhibit environmental stress crack resistance. The melt flow rate (MFR) can be adjusted by allowing hydrogen to be present in the polymerization system at the time of producing the component (B) and adjusting the concentration thereof, adjusting the polymerization temperature, or the like.

<< Requirements (B-5) >>
The component (B) preferably has a density measured in accordance with ASTM D1505 in the range of 830 to 940 kg / m ³ , more preferably 840 to 920 kg / m ³ , and even more preferably 850 to 910 kg / m ³ . be.

[Method for producing polymer (B)]
The method for producing the polymer (B) is a step of homopolymerizing 1-butene in the presence of the following olefin polymerization catalyst, or copolymerizing 1-butene with at least one selected from ethylene and propylene. Have. Other monomers may be further copolymerized as long as the above requirements are met.

As a method for obtaining the component (B), a known polymerization method such as a vapor phase method, a bulk method, a slurry method, or a solution method can be used to obtain a monomer in the presence of a catalyst for olefin polymerization such as a Ziegler-Natta catalyst or a metallocene catalyst. A method of polymerizing with a catalyst can be mentioned. It is preferable to polymerize the monomer using the metallocene compound (b1) represented by the following formula (1) or (2).

The catalyst is selected from the organoaluminum oxy compound (b21), the compound (b22) that reacts with the metallocene compound (b1) to form an ion pair, and the organoaluminum compound (b23), in addition to the metallocene compound (b1). It is preferable to contain at least one component (b2). Further, the catalyst may contain a particulate carrier (b3), if necessary.

<Metallocene compound (b1)>

式（１）および（２）中、Ｒ²は炭化水素基またはケイ素含有炭化水素基であり、Ｒ¹、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²はそれぞれ独立に水素、炭化水素基またはケイ素含有炭化水素基であり、Ｒ⁵からＲ¹²までの隣接した置換基は互いに結合して環を形成してもよく、Ａは一部に不飽和結合および／または芳香族環を含んでいてもよい炭素数２～２０の２価の炭化水素基であり、ＡはＹと共に形成する環を含めて２つ以上の環構造を含んでいてもよく、Ｍは周期表第４族から選ばれる金属であり、Ｙは炭素またはケイ素であり、Ｑはハロゲン、炭化水素基、アニオン配位子または孤立電子対で配位可能な中性配位子から同一または異なる組合せで選ばれ、ｊは１～４の整数である。

In formulas (1) and (2), R ² is a hydrocarbon group or a silicon-containing hydrocarbon group, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R. ¹⁰ , R ¹¹ and R ¹² are independently hydrogen, hydrocarbon groups or silicon-containing hydrocarbon groups, and adjacent substituents from R ⁵ to R ¹² may be bonded to each other to form a ring, A. Is a divalent hydrocarbon group having 2 to 20 carbon atoms which may contain an unsaturated bond and / or an aromatic ring in part, and A has two or more ring structures including a ring formed with Y. M is a metal selected from Group 4 of the periodic table, Y is carbon or silicon, and Q is a halogen, a hydrocarbon group, an anionic ligand or an isolated electron pair. Selected from neutral ligands in the same or different combinations, j is an integer from 1 to 4.

Examples of the hydrocarbon group include a hydrocarbon group having 1 to 20 carbon atoms, specifically, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, and 7 to 20 carbon atoms. The arylalkyl group of the above, an aryl group having 6 to 20 carbon atoms, and an alkylaryl group having 7 to 20 carbon atoms may be mentioned, and may contain one or more ring structures. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, 2-methylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,1-diethylpropyl and 1-ethyl-1-methylpropyl. Examples thereof include 1,1,2,2-tetramethylpropyl, sec-butyl, tert-butyl, 1,1-dimethylbutyl, cyclohexyl and phenyl.

Examples of the silicon-containing hydrocarbon group include an alkylsilyl group having 1 to 4 silicon and a carbon number of 3 to 20 and an arylsilyl group, and specific examples thereof include trimethylsilyl, tert-butyldimethylsilyl and triphenylsilyl. Can be mentioned.

R ² is a sterically bulky hydrocarbon group or a silicon-containing hydrocarbon group, that is, a secondary or tertiary substituent is preferable, and a substituent having 4 or more carbon atoms is more preferable. Specific hydrocarbon groups include isopropyl, 1,1-dimethylpropyl, 1,1-diethylpropyl, 1-ethyl-1-methylpropyl, 1,1,2,2-tetramethylpropyl, sec-butyl, and Examples thereof include tert-butyl and 1,1-dimethylbutyl. Particularly preferred is tert-butyl. Examples of the silicon-containing hydrocarbon group include a group in which a part or all of the carbon of the hydrocarbon group is replaced with silicon.

Adjacent substituents from R ⁵ to R ¹² on the fluorene ring may combine with each other to form a ring. Examples of such substituted fluorenyl groups include benzofluorenyl, dibenzofluorenyl. Further, the substituents of R ⁵ to R ¹² on the fluorene ring are bilaterally symmetric because of the ease of synthesis, that is, R ⁵ = R ¹² , R ⁶ = R ¹¹ , R ⁷ = R ¹⁰ , and R ⁸ = R ⁹ . It is preferably unsubstituted fluorene, 3,6-disubstituted fluorene, 2,7-2-substituted fluorene or 2,3,6,7-4-substituted fluorene. Here, the 3rd, 6th, 2nd, and 7th positions on the fluorene ring correspond to R ⁷ , R ¹⁰ , R ⁶ , and R ¹¹ , respectively.

R ³ and R ⁴ in the formula (1) are preferably hydrogen or a hydrocarbon group, and may be the same or different from each other. Specific examples of the hydrocarbon group include the same as above. Preferred specific examples of −Y (R ³ ) (R ⁴ ) — in the formula (1) include, for example, methylene, dimethylmethylene, diisopropylmethylene, methyltert-butylmethylene, dicyclohexylmethylene, methylcyclohexylmethylene, and methylphenylmethylene. , Diphenylmethylene or dimethylsilylene, diisopropylsilylene.

More preferred Y is carbon.
When R ² in the formula (1) or (2) is a tert-butyl group, R ¹ is preferably a methyl group or an ethyl group, preferably a methyl group. In this case, R ³ and R ⁴ in the formula (1) are a methyl group or a phenyl group, preferably a methyl group. Further, it is preferable that R ³ and R ⁴ are the same as each other. Further, when R ² in the formulas (1) and (2) is a tert-butyl group and R ¹ is a methyl group, R ⁵ to R ¹² may be hydrogen. Further, when R ² in the formula (1) is a tert-butyl group and R ¹ is an ethyl group, R ⁵ , R ⁷ , R ⁸ and R ⁹ , R ¹⁰ and R ¹² are hydrogen, and R ⁶ and R ¹¹ are obtained. Is preferably a tert-butyl group.

In the case of the formula (2), Y is bonded to A, which is a divalent hydrocarbon group having 2 to 20 carbon atoms, which may partially contain an unsaturated bond and / or an aromatic ring, and is cycloalkrylidene. It constitutes a group, a cyclomethylene silylene group, or the like. Preferred specific examples include, for example, cyclopropylidene, cyclobutylidene, cyclopentylidene, and cyclohexylidene.

M in the formulas (1) and (2) is a metal selected from Group 4 of the periodic table, and examples of M include titanium, zirconium, and hafnium. Q is selected from halogens, hydrocarbon groups, anionic ligands or neutral ligands that can be coordinated with lone electron pairs in the same or different combinations. Specific examples of the halogen are fluorine, chlorine, bromine, and iodine, and specific examples of the hydrocarbon group include the same as above in R ¹ to R ¹² . Specific examples of the anion ligand include an alkoxy group such as methoxy and tert-butoxy, an allyloxy group such as phenoxy, a carboxylate group such as acetate and benzoate, and a sulfonate group such as mesylate and tosylate. Specific examples of the neutral ligand that can be coordinated with a lone electron pair include organic phosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, and diphenylmethylphosphine, tetrahydrofuran, diethyl ether, dioxane, and 1,2-dimethoxy. Examples include ethers such as ethane. Of these, Q may be the same or a different combination, but at least one is preferably a halogen or an alkyl group.

<Component (b2)>
The component (b2) is at least one selected from the organoaluminum oxy compound (b21), the compound (b22) that reacts with the metallocene compound (b1) to form an ion pair, and the organoaluminum compound (b23). be.

<< Ingredient (b21) >>
Conventionally known aluminoxane can be used as the component (b21).

<< Ingredient (b22) >>
Examples of the component (b22) include Lewis acid, an ionic compound, a borane compound and a carborane compound described in JP-A No. 1-501950 and JP-A-2004-51676. Further, heteropoly compounds and isopoly compounds are also mentioned.

Specifically, triarylborane such as triphenylborane, tris (o-tolyl) borane, tris (p-tolyl) borane, tris (3,5-dimethylphenyl) borane; triarylborane such as trimethylborane and triisobutylborane. Alkylborane; compounds having a fluorine-containing aryl group such as tris (4-fluorophenyl) borane, tris (3,5-difluorophenyl) borane, tris (4-fluoromethylphenyl) borane, tris (pentafluorophenyl) borane, etc. Compounds having a halogen-containing aryl group; trifluoroborane can be mentioned.

<< Ingredient (b23) >>
Examples of the component (b23) include organoaluminum compounds represented by _Ram Al (OR ^{b )} _n H _p X _q . In the above formula, R ^a and R ^b are each independently a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, X is a halogen atom, and m is 0 <m ≦ 3, n. Is a number of 0 ≦ n <3, p is 0 ≦ p <3, q is a number of 0 ≦ q <3, and m + n + p + q = 3.

Specific examples of the component (b23) include, for example, tri-n-alkyl aluminum such as trimethylaluminum, triethylaluminum and trin-butylaluminum; tri-branched alkylaluminum such as triisobutylaluminum; diisopropylaluminum hydride, diisobutylaluminum hydride and the like. Dialkylaluminum hydride; Examples thereof include alkylaluminum alkoxides such as isobutylaluminum methoxyd and isobutylaluminum ethoxide. Among these, tri-n-alkylaluminum and tribranched-chain alkylaluminum are preferable, and trimethylaluminum and triisobutylaluminum are more preferable.

<Particulate carrier (b3)>
Examples of the particulate carrier (b3) include inorganic or organic compounds and particulate solids. Examples of the inorganic compound include porous oxides, inorganic halides, clays, clay minerals, and ion-exchangeable layered compounds. Examples of the organic compound include particulate α-olefin polymers.

<Polymerization conditions>
The above polymerization can be carried out by any of a liquid phase polymerization method such as bulk polymerization, suspension polymerization and dissolution polymerization, or a vapor phase polymerization method. In the liquid phase polymerization method, an inert hydrocarbon solvent may be used, and specifically, aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, and decane; cyclopentane, cyclohexane, and methylcyclopentane. Alicyclic hydrocarbons such as; aromatic hydrocarbons such as benzene, toluene, xylene; and mixtures of two or more of these. It is also possible to carry out bulk polymerization using the olefins themselves containing 1-butene as a solvent.

In the above-mentioned polymerization, it is also possible to carry out so-called multi-stage polymerization in which the polymerization conditions are changed stepwise. For example, it is also possible to obtain polymers (B) having various molecular weight distributions by carrying out polymerization stepwise under two kinds of conditions in which the amount of hydrogen used is different. It is also possible to obtain a polymer (B) having a controlled composition distribution by performing homopolymerization of 1-butene and copolymerization of 1-butene with other olefins in stages.

During the polymerization, the component (b1) is usually 10 ^-8 to ^10-2 mol, preferably 10 ^-7 to 10 ^-3 mol, in terms of Group 4 metal atoms in the periodic table, per liter of the reaction volume. Used in large quantities. The molar ratio [Al / M] of the aluminum atom in the component (b21) and the metal atom (M) of Group 4 of the periodic table in the component (b1) is usually 0.01 to 5000 in the component (b21). It is preferably used in an amount such that it is 0.05 to 2000. The molar ratio [b22 / M] of the component (b22) to the group 4 metal atom (M) in the periodic table in the component (b22) is usually 1 to 10, preferably 1 to 5. It is used in such an amount. The molar ratio [b23 / M] of the component (b23) to the group 4 metal atom (M) of the periodic table in the component (b1) is usually 10 to 5000, preferably 20 to 2000. It is used in such an amount.

The polymerization temperature is usually in the range of −50 to 200 ° C., preferably 0 to 100 ° C., and more preferably 20 to 100 ° C. The polymerization pressure is usually under the conditions of normal pressure to 10 MPa gauge pressure, preferably normal pressure to 5 MPa gauge pressure, and the polymerization reaction can be carried out by any of batch type, semi-continuous type and continuous type. .. Further, it is also possible to carry out the polymerization in two or more stages having different reaction conditions.
Hydrogen can be added for the purpose of controlling the molecular weight and polymerization activity of the polymer (B) produced during polymerization, and the amount thereof is appropriately about 0.001 to 100 NL per 1 kg of olefin.

[Other polymer (C)]
As the other polymer (C), a thermoplastic resin different from the high-pressure method low-density polyethylene (A) and the polymer (B) can be widely used. The content of the other polymer (C) is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, based on the total mass of the composition (X). The other polymer (C) may be used alone or in combination of two or more.

The thermoplastic resin is not particularly limited, but is not particularly limited.
Thermoplastic polyolefin-based resins: For example, polyethylene such as low-density, medium-density, high-density polyethylene (excluding high-pressure low-density polyethylene (A)), isotactic polypropylene, polypropylene such as syndiotactic polypropylene, poly 4-methyl. -1-Pentene, Poly3-methyl-1-pentene, Poly3-methyl-1-butene, Ethylene / α-olefin copolymer, Propropylene / α-olefin copolymer, 1-butene / α-olefin copolymer weight Combined, 4-methyl-1-pentene / α-olefin copolymer (excluding polymer (B) in these), cyclic olefin copolymer, chlorinated polyolefin, and modified polyolefin resin modified from these olefin-based resins. ,
Thermoplastic polyamide resin: For example, aliphatic polyamide (eg, nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612),
Thermoplastic polyester resin: for example, polyethylene terephthalate, polybutylene terephthalate, polyester elastomer,
Thermoplastic vinyl aromatic resin: For example, polystyrene, ABS resin, AS resin, styrene-based elastomer (eg, styrene / butadiene / styrene block polymer, styrene / isoprene / styrene block polymer, styrene / isobutylene / styrene block polymer, these Hydrogen additive),
Thermoplastic polyurethane; vinyl chloride resin; vinylidene chloride resin; acrylic resin; vinyl acetate copolymer such as ethylene / vinyl acetate copolymer; ethylene / methacrylate acrylate copolymer; ionomer; ethylene / vinyl alcohol copolymer; polyvinyl Alcohol; Fluorine resin; Polycarbonate; Polyacetal; Polyphenylene oxide; Polyphenylene sulfide polyimide; Polyallylate; Polysulfone; Polyether sulfone; Rosin resin; Terpen resin and petroleum resin;
Polymer rubber: For example, ethylene / α-olefin / diene copolymer, propylene / α-olefin / diene copolymer, 1-butene / α-olefin / diene copolymer, polybutadiene rubber, polyisobutylene rubber, neoprene. Rubber, nitrile rubber, butyl rubber, polyisobutylene rubber, natural rubber, silicone rubber;
Etc. are exemplified.
Part or all of the other polymer (C) may be graft-modified with a polar monomer.

[Additive (D)]
Examples of the additive (D) include nucleating agents, antiblocking agents, pigments, dyes, fillers, lubricants, thermoplastics, mold release agents, antioxidants, flame retardants, ultraviolet absorbers, antibacterial agents, and surfactants. , Antistatic agent, Weather-resistant stabilizer, Heat-resistant stabilizer, Anti-slip agent, Foaming agent, Crystallization aid, Anti-fog agent, Anti-aging agent, Hydroxyl absorber, Impact improver, Cross-linking agent, Co-cross-linking agent, Cross-linking aid Examples include agents, pressure-sensitive adhesives, softeners, and processing aids.

The additive (D) may be used alone or in combination of two or more.
The content of the additive (D) is not particularly limited depending on the intended use within a range that does not impair the object of the present invention, but is 0.001 for each of the additives to be blended in the total mass of the composition (X). It is preferably about 30% by mass.

[Characteristics of composition (X)]
As described above, the composition (X) of the present invention has the characteristics of being excellent in tearability and ESCR. The inventors think that the reason why this property is exhibited is as follows. In the composition (X), a sea-island structure in which the high-pressure low-density polyethylene (A) becomes a sea phase and the polymer (B) becomes an island phase is formed, so that tensile elongation is suppressed and the tearability is excellent. When the tendency is obtained and the glass transition temperature (Tg) of the polymer (B) forming the island phase is below a specific temperature, the flexibility of the island phase is ensured and the stress applied to the molded body is effective. It is presumed that the occurrence of cracks can be suppressed by alleviating the temperature.

[Method for producing composition (X)]
The method for producing the composition (X) of the present invention is not particularly limited, but for example, the high-pressure method low-density polyethylene (A), the polymer (B), and other arbitrary components are mixed and then melt-kneaded. can get.

The method of melt-kneading is not particularly limited, and it can be carried out by using a melt-kneading device such as a generally commercially available extruder. For example, the temperature of the portion to be kneaded by the melt kneading device is usually 120 to 250 ° C, preferably 120 to 230 ° C. The kneading time is usually 0.5 to 30 minutes, preferably 0.5 to 5 minutes.

[Molded product]
Various molded products containing the composition (X) of the present invention can be widely used for conventionally known polyolefin applications. The molded body is obtained by a known heat molding method such as extrusion molding, injection molding, inflation molding, blow molding, extrusion blow molding, injection blow molding, press molding, vacuum molding, powder slush molding, calendar molding, foam molding and the like. Will be.

As the molding conditions, general polyethylene molding conditions can be applied. For example, a resin temperature of about 160 to 240 ° C. for injection molding, about 150 to 230 ° C. for blow molding, and about 130 to 240 ° C. for extrusion molding are appropriate.

Examples of applications that require tearability include applications such as a container in which a part of a cap or the like is torn off and opened. More specifically, there are applications such as food containers, pharmaceutical containers, cosmetic containers, detergent containers, industrial chemical containers, pesticide containers, etc., which require high safety and airtightness of the containers. Examples of the food container include liquid seasonings (eg, dressing), beverages, one-way containers for ice cream, squeezing containers, confectionery containers such as gum bottles, and container lids for dried plums and wasabizuke. Examples of the pharmaceutical container include a single-use eye drop container, a container cap for eye drops and liquid medicine that is torn when opened, a tablet container cap, and a drug solution container used in a hospital. Examples of the cosmetic container include a container for cream, a lotion, and a cleansing container.

Applications that require high ESCR in addition to tearability include, for example, containers for contents containing a surfactant, such as detergent containers, cosmetic containers, and industrial chemical containers. That is, as the molded product of the present invention, a container containing a content containing a surfactant (eg, detergent, cosmetics, industrial chemicals) and used by tearing off the opened portion is mentioned as a preferable use.

The present invention will be described in detail based on examples, but the present invention is not limited to these examples.
[Synthesis Example 1] Propylene-butene-ethylene copolymer (PBER)
After charging 917 ml of dry hexane, 85 g of 1-butene and 1.0 mmol of triisobutylaluminum into a 2000 ml polymerizer fully substituted with nitrogen at room temperature, the temperature inside the polymerizer was raised to 65 ° C. and the system was filled with propylene. After pressurizing the pressure to 0.77 MPa, the internal pressure of the system was adjusted to 0.78 MPa with ethylene. Next, dimethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) fluorenyl zirconium dichloride and a toluene solution of methylaluminoxane (manufactured by Toso Finechem Co., Ltd.) are mixed to form an aluminum atom and zirconium. A toluene solution was prepared in which the atoms were contained in a ratio of aluminum atom / zirconium atom = 300/1 (molar ratio). Then, an amount containing 0.002 mmol of zirconium atom (hence, an amount containing 0.6 mmol of aluminum atom) in the toluene solution was collected and added into the polymerization apparatus. Polymerization was carried out for 20 minutes while keeping the internal temperature at 65 ° C. and the internal pressure at 0.78 MPa with ethylene, and 20 ml of methanol was added to terminate the polymerization. After depressurization, the copolymer was precipitated from the polymerization solution in 2 L of methanol and dried under vacuum at 130 ° C. for 12 hours. The yield of the obtained copolymer was 60.4 g. The above steps were scaled up and carried out to obtain a sufficient amount of copolymer.

The obtained copolymer contains 500 wtppm of the antioxidant Irganox 1076 and 500 wtppm of Irgafos 168, and uses a φ40 mm single-screw extruder manufactured by Modern Machinery Co., Ltd., a cylinder temperature of 210 ° C., a screw rotation speed of 50 rpm, and a kneading time. After melt-kneading in 2 minutes and cooling and solidifying the molten strands discharged from the φ4 mm round hole die in a water tank set at 10 ° C., a strand cutter (model ST-SG3.0) manufactured by FREESIA MACROSS CO., LTD. Pellets were obtained by cutting.
Table 1 shows the resins used in Examples, Reference Examples and Comparative Examples, and the following analytical values. In the table, "-" means no data unless otherwise specified.

[Content of constituent units]
The content of the building blocks was calculated from the ¹³ C-NMR spectrum according to the following equipment and conditions.
Measuring device: Nuclear magnetic resonance device
(AVANCE III cryo-500 type manufactured by Bruker Biospin Co., Ltd.)
Observation nucleus: ¹³ C (125 MHz)
Sequence: Single pulse Proton broadband decoupling Pulse width: 5.0 μsec (45 ° pulse)
Number of points: 64k
Repeat time: 5.5 seconds Accumulation number: 128 times Solvent: o-dichlorobenzene / deuterated benzene (volume ratio: 4/1) mixed solvent Sample concentration: 60 mg / 0.6 mL
Measurement temperature: 120 ° C
Reference value for chemical shift: 29.73 ppm

[Glass transition temperature (Tg)]
Using a dynamic viscoelastic device RSA-III manufactured by TA Instruments, the temperature range of −90 to 200 ° C. was raised at 3 ° C./min in a nitrogen atmosphere. The applied strain was 0.1% and the frequency was 1 Hz. The temperature at which the loss elastic modulus (E'') showed a maximum value was defined as the glass transition temperature (Tg).

[density]
Density was measured according to ASTM D1505 (Density Gradient Tube Method).

[Melt flow rate (MFR)]
The melt flow rate (MFR) was measured under the conditions of 190 ° C., 2.16 kg load or 230 ° C., 2.16 kg load according to ASTM D1238.

[Example 4, Reference Examples 1 to 3, Comparative Examples 2 to 4, 6 to 11]
According to the composition shown in Table 2, after the pellets of each resin are mixed (dry blended) at room temperature, a cylinder temperature of 210 ° C., a screw rotation speed of 50 rpm, and a kneading time are used using a φ40 mm single-screw extruder manufactured by Modern Machinery Co., Ltd. After melt-kneading in 2 minutes and cooling and solidifying the molten strands discharged from the φ4 mm round hole die in a water tank set at 10 ° C., a strand cutter (model ST-SG3.0) manufactured by Freesia Macross Co., Ltd. is used. Pellets were obtained by cutting. The obtained pellets were evaluated by the following method. The results are also shown in Table 2.

[Comparative Examples 1, 5, 12]
The resin pellets shown in Table 2 were evaluated by the following method. The results are also shown in Table 2.

[Making injection test pieces]
For pellets, an injection molding machine manufactured by Meiki Seisakusho Co., Ltd. (model MEIKI M-50AII-DM, mold clamping force 50 tons) was used, the cylinder temperature was 210 ° C, the mold temperature was 30 ° C, and the thickness was 70 MPa at the injection pressure. A 3 mm test piece was obtained. The obtained test piece was used for a tensile test and a Shore D hardness measurement.

《Tensile test》
The condition of the test piece was adjusted at 23 ° C. for 3 days, and according to ATM D638, a tensile tester manufactured by Intesco Co., Ltd. (model 2005-5) was used at 23 ° C., a chuck distance of 64 mm, and a test speed of 50 mm / min. Tensile modulus (YM), yield point elongation (YEL), yield point strength (YS), breaking point elongation (EL), and breaking point strength (TS) were measured. The yield point elongation and the breaking point elongation were calculated as the inter-chuck elongation ratio. In Table 2, "-" in YEL and YS means that there was no yield point.

《Shore D hardness》
The state of the test piece was adjusted at 23 ° C. for 24 hours, and the pressurized surface of the durometer was vertically pressed from directly above at a constant speed according to ASTM D2240, and the value immediately after close contact was defined as "hardness".

[Making a press sheet]
For pellets, use a hydraulic heat press machine manufactured by Kansai Roll Co., Ltd. set at 210 ° C, preheat for about 5 minutes, pressurize at 7.5 MPa for 2 minutes, and then set another Kansai roll (stock) at 20 ° C. ) Using a hydraulic heat press, the sample was compressed at 7.5 MPa and cooled for 4 minutes to prepare a measurement sample consisting of a press sheet having a thickness of 2 mm.

<< Stress cracking resistance (ESCR) >>
Using a punched test piece from a press sheet, a half fracture time F50 value was determined.
Vent strip method: ASTM D1693
Chemical solution: Igepearl CO 630
Chemical concentration: 10%
Test temperature: 50 ° C
Notch depth: 0.35 mm
Maximum time: 600hrs

[Melt flow rate (MFR)]
Melt flow rate (MFR) was measured in accordance with ASTM D1238 under the conditions of 190 ° C. and 2.16 kg load.

[evaluation]
As shown in Table 2, the comparative example composition containing no polymer (B) and containing LDPE as a main component did not have a sufficient ESCR value (Comparative Examples 1 to 4, 10 and 11). Further, the comparative example composition containing LLDPE as a main component without containing LDPE had a large tensile elongation (Comparative Examples 5 to 9, 12). On the other hand, since the Example composition and the Reference Example composition contain LDPE and the polymer (B), the EL value is 130% or less and the ESCR value is 12 hrs or more, and the molded product is torn off. Excellent in sex and ESCR.

Claims (1)

High-pressure method low-density polyethylene (A) 80 to 92 parts by mass,
A composition comprising 8 to 20 parts by mass of a polymer (B) satisfying the following requirements (B-1) to (B-3) (however, the total of the above (A) and (B) is 100 parts by mass). Including thing (X)
A molded product that is a container selected from the group consisting of food containers, pharmaceutical containers, cosmetic containers, detergent containers, industrial chemical containers, and pesticide containers.
(B-1) The total T of the contents of the 1-butene-derived structural unit (U1), the ethylene-derived structural unit (U2), and the propylene-derived structural unit (U3) is 100 mol%. When it is used, the content of U1 is 19 to 50 mol%.
(B-2) The content of U2 is 40 mol% or less of the total constituent unit amount.
(B-3) The glass transition temperature (Tg) measured by dynamic viscoelasticity measurement is
It is -15 ° C or lower.