JP2023149991A - Polyolefin resin molding material and pet bottle cap for non-carbonic acid beverage - Google Patents

Abstract

To provide a polyolefin resin molding material that achieves the enhanced durability of polyolefin resin, recycled by homogenizing Pet bottle caps recovered from the market using material recycling techniques, and a PET bottle cap for non-carbonic acid beverage molded therewith.SOLUTION: The present invention provides: a polyolefin resin molding material that contains a polyolefin recovered resin, obtained by homogenizing market-recovered products of resin caps of PET bottles, and a modifier made of a specific polyethylene resin, with the content of the modifier being 1 to 99 mass% based on the total amount of the polyolefin recycled resin and the modifier; and a PET bottle cap for non-carbonated beverages formed by molding the polyolefin resin molding material.SELECTED DRAWING: None

Description

The present invention relates to a polyolefin resin molding material, and more particularly to a polyolefin resin molding material suitable for lids of containers containing liquids such as soft drinks, particularly non-carbonated drinks, and a market recovery product of PET bottle caps. A recycled polyolefin resin molding material obtained by modifying a recovered polyolefin resin obtained by homogenizing it using a material recycling method, and a product molded using the polyolefin resin molding material. This invention relates to a PET bottle cap for non-carbonated beverages.

Plastic containers, especially PET (polyethylene terephthalate) bottles, have been in demand as containers for soft drinks since they were approved as containers for food and beverages due to their excellent mechanical strength, transparency, high gas barrier properties, and non-polluting properties. is very high. In particular, small PET bottles are heavily used by consumers as small containers for portable beverages, and the heat resistance and pressure resistance of PET bottles have been improved, allowing for portable high-temperature beverages for winter use and high-temperature sterilization for long-term storage. It is also commonly used as a container for processed beverages.

In addition, PET containers for soft drinks such as carbonated drinks have traditionally been made of metal such as aluminum for their lids, but due to economic considerations, polyolefin containers are increasingly being used. It has become. Containers for soft drinks, etc., require performance that is essential such as sealability, ease of opening, food safety, and durability, but lid materials also require not only these performances, but also moldability, rigidity, heat resistance, etc. From the viewpoint of various physical properties of polyethylene resin lid members, technical improvement studies are continuing, and a large number of improvements have been proposed.

Polyethylene resin molding materials suitable for PET bottle caps for carbonated beverages have high-speed moldability, high fluidity, rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, and easy opening. A polyethylene resin molding material is known which is generally excellent in closure properties, has good long-term durability even at high temperatures, and is particularly suitable for container lids with improved Charpy impact strength (Patent Document 1). .

JP2015-151181

While PET bottle caps made of polyethylene resin have become popular and widely used, in recent years, environmental and recycling perspectives have become more important when it comes to resin products, such as plastic waste issues and carbon neutrality. As a result, there is a strong demand for PET bottle caps to be recycled and used as a plastic resource, rather than just being thrown away.

Recycling efforts such as separate collection of PET bottle caps are widely carried out, and efforts are being made to effectively utilize resources. However, since PET bottle caps collected on the market are a collection of products with various physical properties ranging from high to low, there are problems in terms of performance, especially durability (stress crack resistance). Therefore, it is difficult to recycle it as it is as a PET bottle cap.

In view of the state of the prior art, the present invention aims to improve the durability (stress crack resistance) of a polyolefin resin that is recycled as a material resin by homogenizing PET bottle caps collected on the market using a material recycling method. A recycled polyolefin resin molding material that has been modified to a level that can be used as a regular non-carbonated beverage PET bottle cap product, and a non-carbonated beverage PET molded using the modified polyolefin resin molding material. The purpose is to provide bottle caps.

As a result of repeated studies by the present inventors in order to solve the above problems, the polyethylene resin molding material suitable for PET bottle caps for carbonated beverages, described in Patent Document 1, was applied to PET bottles recovered from the market. By adding it as a modifier to the polyolefin resin that is recycled by crushing and homogenizing the cap, it can be recycled from PET bottle caps collected on the market without damaging the rigidity of the polyolefin resin during modification. It has been found that the durability (stress crack resistance) of the polyolefin resin can be improved to a level that allows it to be used as a PET bottle cap product for non-carbonated beverages.

The first invention of the present invention includes a polyolefin-based recovered resin obtained by homogenizing market recovered products of polyolefin-based resin caps of PET bottles, and a modifying material made of the following polyethylene-based resin,
A polyolefin resin molding material in which the content of the modifier is 1 to 99% by mass based on the total amount of the recovered polyolefin resin and the modifier.
[Modified material made of polyethylene resin]
The ethylene polymer contains the following component (A) in an amount of 20% by mass or more and 40% by mass or less, and component (B) in an amount of 60% by mass or more and 80% by mass or less, and has the following properties (1) to (4). A modified material made of polyethylene resin that satisfies the requirements.
Component (A): HLMFR is 0.05 to 5.0 g/10 min, density is 0.910 to 0.935 g/cm ³ , and determined by formula (a) from the measured value of ¹³ C-NMR spectrum. Ethylene polymer with CSD (comonomer sequence distribution) value (CSD _A ) of 0.0 to 3.0 CSD = 4 × [EE] [CC] / [EC] ² formula (a)
(In formula (a), [EE] represents the number of ethylene/ethylene chains, [CC] represents the number of comonomer/comonomer chains, and [EC] represents the number of ethylene/comonomer chains.)
Component (B): Ethylene polymer with MFR of 100 g/10 min or more and less than 600 g/10 min, density of 0.960 g/cm ³ or more and less than 0.980 g/cm ³ Characteristics (1): Temperature 190°C/Load 2 .The melt flow rate (MFR) at 16 kg is 0.2 g/10 minutes or more and 3.0 g/10 minutes or less, and the high load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is 70 g/10 minutes or more and 180 g. /10 minutes, and HLMFR/MFR is 50 to 500 Characteristic (2): Density is 0.955 g/cm ³ or more and 0.970 g/cm ³ or less Characteristic (3): 80 by full notch creep test ℃, 1.9 MPa rupture time (FNCT) is 100 hours or more Characteristic (4): Charpy impact strength is 9.0 KJ/m ² or more

A second invention of the present invention is characterized in that, in the first invention, the polyolefin resin molding material has a flexural modulus of 900 MPa or more.

A third invention of the present invention is characterized in that, in the first or second invention, the polyolefin resin molding material has an environmental stress cracking resistance (ESCR) of 45 hours or more.

A fourth invention of the present invention is characterized in that, in the first to third inventions, the modifying material made of the polyethylene resin further satisfies the following characteristics (5) to (6).
Characteristic (5): Flexural modulus is 900 to 1,500 MPa Characteristic (6): Melting viscosity at 190°C and shear rate of 400 sec ^-1 is 200 to 1,000 Pa・s

A fifth invention of the present invention is characterized in that, in the first to fourth inventions, at least one of the component (A) and the component (B) of the ethylene polymer is capable of polymerizing at least two groups in the presence of a polymerization catalyst. In multi-stage polymerization using a combination of reactors, an ethylene homopolymer is polymerized in at least one of the two polymerization reactors, and an ethylene homopolymer having a carbon number of 3 to 3 is polymerized in at least the other of the two polymerization reactors. It is characterized by being obtained by polymerizing an ethylene copolymer with No. 20 α-olefin.

A sixth invention of the present invention is the fifth invention, wherein the polymerization catalyst for the ethylene polymer has the general formula Mg(OR ² ) _m X ² _2-m (wherein R ² is alkyl, aryl or represents a cycloalkyl group, X ² represents a halogen atom, and m is 1 or 2) and the compound represented by the general formula Ti(OR ³ ) _n X ³ _4-n (wherein R ³ is alkyl, represents a aryl or cycloalkyl group, X ³ represents a halogen atom, and n is ¹ _, 2 or ³ ) _. (In the formula, R ¹ represents an alkyl, aryl, or cycloalkyl group, X ¹ represents a halogen atom, and l represents a number of 1≦l≦2.) The catalyst is characterized by containing the obtained hydrocarbon-insoluble solid catalyst and an organoaluminum compound.

A seventh invention of the present invention is characterized in that, in the first to sixth inventions, the polyolefin resin molding material is used for molding a PET bottle cap for a non-carbonated beverage.

An eighth invention of the present invention is characterized in that, in the first to sixth inventions, the polyolefin resin molding material is used for continuous compression molding of a PET bottle cap for a non-carbonated beverage.

A ninth invention of the present invention is a PET bottle cap for non-carbonated beverages formed by molding the polyolefin resin molding material of the first to sixth inventions.

According to the present invention, a polyolefin-based recovered resin obtained by homogenizing used PET bottle caps is modified by adding a polyethylene-based resin having excellent rigidity and durability (stress crack resistance). Improve the durability (stress crack resistance) of recovered polyolefin resin to the level required for ordinary PET bottle cap products for non-carbonated beverages without significantly changing the physical properties required for the product, especially without impairing rigidity. be able to.
Therefore, it is possible to obtain a polyolefin resin molding material with a better balance of physical properties than a recovered polyolefin resin made by simply homogenizing PET bottle caps collected on the market. It becomes possible to realize material recycling from caps to new PET bottle caps.

Figure 1 shows the CSD _A (comonomer sequence distribution) and SCB _A (short chain comonomer sequence distribution with 1 to 20 carbon atoms per 1,000 carbon atoms in the main chain) of component (A) of the modifier used in the present invention. 12 is a graph showing equation (b) showing a preferable relationship between the number of branches and the number of branches.

Hereinafter, the characteristics of the polyolefin resin molding material of the present invention will be specifically described in detail. In the present invention, "~" indicating a numerical range is used to include the numerical values written before and after it as a lower limit value and an upper limit value.
The polyolefin resin molding material of the present invention includes a recovered polyolefin resin obtained by homogenizing market recovered products of polyolefin resin caps of PET bottles, and a modifying material made of the following polyethylene resin, The resin composition is characterized in that the content of the modifier is 1 to 99% by mass based on the total amount of the recovered polyolefin resin and the modifier.
[Modified material made of polyethylene resin]
The ethylene polymer contains the following component (A) in an amount of 20% by mass or more and 40% by mass or less, and component (B) in an amount of 60% by mass or more and 80% by mass or less, and has the following properties (1) to (4). A modified material made of polyethylene resin that satisfies the requirements.
Component (A): HLMFR is 0.05 to 5.0 g/10 min, density is 0.910 to 0.935 g/cm ³ , and determined by formula (a) from the measured value of ¹³ C-NMR spectrum. Ethylene polymer with CSD (comonomer sequence distribution) value (CSD _A ) of 0.0 to 3.0 CSD = 4 × [EE] [CC] / [EC] ² formula (a)
(In formula (a), [EE] represents the number of ethylene/ethylene chains, [CC] represents the number of comonomer/comonomer chains, and [EC] represents the number of ethylene/comonomer chains.)
Component (B): Ethylene polymer with MFR of 100 g/10 min or more and less than 600 g/10 min, density of 0.960 g/cm ³ or more and less than 0.980 g/cm ³ Characteristics (1): Temperature 190°C/Load 2 .The melt flow rate (MFR) at 16 kg is 0.2 g/10 minutes or more and 3.0 g/10 minutes or less, and the high load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is 70 g/10 minutes or more and 180 g. /10 minutes, and HLMFR/MFR is 50 to 500 Characteristic (2): Density is 0.955 g/cm ³ or more and 0.970 g/cm ³ or less Characteristic (3): 80 by full notch creep test ℃, 1.9 MPa rupture time (FNCT) is 100 hours or more Characteristic (4): Charpy impact strength is 9.0 KJ/m ² or more

1. Market recovered polyolefin resin caps for PET bottles In the present invention, market recovered polyolefin resin caps for PET bottles refer to polyolefin resin caps that are separately collected from used PET bottles. Resin caps for PET bottles are molded products of polyolefin resins such as polyethylene and polypropylene, and polyethylene caps are particularly widely used. Polyolefin resin caps can be separated and collected using known methods. For example, depending on the specific gravity difference between the resins forming the cap, only the polyolefin resin caps can be separated, and if necessary, only the polyethylene resin caps can be collected. Can be separated. Among the polyolefin resin caps for PET bottles, it is preferable to use only polyethylene caps and sorted market recovered products from the viewpoint of improving the quality of the polyolefin resin molding material obtained in the present invention.
In the present invention, the recovered polyolefin resin obtained by homogenizing recovered polyolefin resin caps is a recovered product composed of various polyolefin resin caps with different individual qualities that have been pulverized or It is a polyolefin resin composition whose material properties such as resin composition and properties are homogenized by being returned to a raw resin state by a method belonging to material recycling such as pelletization.
Recycled resins made by pulverizing and uniformly mixing the separately collected PET bottle caps and processing them into pellets are generally available on the market. In the present invention, such a commercially available product may be used as a recovered polyolefin resin cap.

The physical property values of PET bottle caps collected on the market vary greatly depending on the quality and proportion of the cap products mixed, so it is not possible to state the physical property values unconditionally. To give an extreme example, if a market recovered product consists mostly of PET bottle cap products for non-carbonated beverages, the performance of the polyolefin-based recovered resin obtained from the market recovered product is equivalent to that of PET bottle cap products for non-carbonated beverages. If the market recovery product is close to the level of PET bottle cap products for carbonated beverages, and is made up mostly of PET bottle cap products for carbonated beverages, the performance of the polyolefin-based recovered resin obtained from the market recovery product will be close to that of PET bottle cap products for carbonated beverages.
Furthermore, if PET bottle caps with poor performance, such as cheap overseas products, are included in the market recovered products, the performance of the polyolefin-based recovered resin obtained from the market recovered products will be adversely affected and deteriorate. Products recovered from the market generally contain a certain amount of PET bottle caps with poor performance, so the performance of the recovered polyolefin resin obtained from PET bottle caps recovered from the market is simply insufficient for use in carbonated beverages. Not only that, but they are of such a level that they cannot even be used as PET bottles for non-carbonated beverages, and in particular, many have too low durability (stress crack resistance) to be used as PET bottles for non-carbonated beverages.

The recovered polyolefin resin to be modified in the present invention has a flexural modulus of 900 to 1000 MPa, which indicates rigidity, and an environmental stress cracking resistance (ESCR) of 15 to 1,000 MPa, which indicates durability (stress crack resistance). A polyolefin-based recovered resin having a recovery time of 35 hours (h) is preferably used. If the flexural modulus of the recovered polyolefin resin is less than 850 MPa, or if the environmental stress cracking resistance (ESCR) of the recovered polyolefin resin is less than 10 hours, the recovered polyolefin resin may be In order to improve the durability (stress crack resistance) to a level where it can be used as a PET bottle cap product for non-carbonated beverages, a large amount of modifying material is required, and the modification efficiency often becomes low. In addition, if the flexural modulus of the recovered polyolefin resin exceeds 1050 MPa and the environmental stress cracking resistance (ESCR) of the recovered polyolefin resin exceeds 45 hours, it can be used as a PET bottle cap product for non-carbonated beverages. Since the performance level is maintained, there is often little need for modification to improve performance.

2. Modifier Made of Polyethylene Resin In the present invention, a polyethylene resin molding material suitable for PET bottle caps for carbonated beverages, which is described in Patent Document 1, is added as a modifier to the recovered polyolefin resin. By doing so, the durability (stress crack resistance) of the recovered polyolefin resin can be improved to a level where it can be used as a PET bottle cap product for non-carbonated beverages, without impairing the rigidity of the recovered polyolefin resin during modification. be able to.
In the present invention, as the modifying material, the raw material virgin resin itself used for molding PET bottle caps for carbonated beverages may be used, or scraps of resin molding material generated during molding of PET bottle caps for carbonated beverages or in-process materials may be used. It is also possible to use recovered products that are recycled and made into pellets.

Specifically, the modifier used in the present invention contains the following component (A) as an ethylene polymer in an amount of 20% by mass or more and 40% by mass or less, and component (B) in an amount of 60% by mass or more and 80% by mass. It is a polyethylene resin that contains the following and satisfies the following characteristics (1) to (4).
Component (A): HLMFR is 0.05 to 5.0 g/10 min, density is 0.910 to 0.935 g/cm ³ , and determined by formula (a) from the measured value of ¹³ C-NMR spectrum. Ethylene polymer with CSD (comonomer sequence distribution) value (CSD _A ) of 0.0 to 3.0 CSD = 4 × [EE] [CC] / [EC] ² formula (a)
(In formula (a), [EE] represents the number of ethylene/ethylene chains, [CC] represents the number of comonomer/comonomer chains, and [EC] represents the number of ethylene/comonomer chains.)
Component (B): Ethylene polymer with MFR of 100 g/10 min or more and less than 600 g/10 min, density of 0.960 g/cm ³ or more and less than 0.980 g/cm ³ Characteristics (1): Temperature 190°C/Load 2 .The melt flow rate (MFR) at 16 kg is 0.2 g/10 minutes or more and 3.0 g/10 minutes or less, and the high load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is 70 g/10 minutes or more and 180 g. /10 minutes, and HLMFR/MFR is 50 to 500 Characteristic (2): Density is 0.955 g/cm ³ or more and 0.970 g/cm ³ or less Characteristic (3): 80 by full notch creep test ℃, 1.9 MPa rupture time (FNCT) is 100 hours or more Characteristic (4): Charpy impact strength is 9.0 KJ/m ² or more

The modifier used in the present invention has a performance level that is compatible with PET bottle cap products for carbonated beverages. The performance of polyethylene resins that do not satisfy the above characteristics (1) to (4) is lower than the performance level suitable for PET bottle cap products for carbonated beverages. Therefore, when using a polyethylene resin that does not satisfy the above properties (1) to (4) as a modifying material for recovered polyolefin resin, a sufficient modification effect cannot be obtained, and the resulting polyolefin resin The performance of the molding material also deteriorates.

(1) Required characteristics as a material for modification material (1)
The modified material made of polyethylene resin has a melt flow rate (MFR) of 0.2 g/10 minutes or more and 3.0 g/10 minutes or less, preferably 0.3 to 3.0 g/10 minutes at a temperature of 190° C. and a load of 2.16 kg. 2.8 g/10 minutes, more preferably 0.5 to 2.5 g/10 minutes. If the MFR is less than 0.2 g/10 minutes, the fluidity will be insufficient and high-speed formability of the modified material of the present invention cannot be expected, and if the MFR exceeds 3.0 g/10 minutes, the stress crack resistance of the modified material of the present invention will be poor. , impact resistance is not necessarily sufficient.
Furthermore, the modified material made of polyethylene resin has a high load melt flow rate (HLMFR) of 70 g/10 minutes or more and less than 180 g/10 minutes at a temperature of 190° C. and a load of 21.6 kg, preferably 80 to 170 g/10 min, more preferably 90 to 160 g/10 min. If the HLMFR is less than 70 g/10 minutes, the fluidity will be insufficient and high-speed moldability of the modified material of the present invention cannot be expected, and if the HLMFR is greater than 180 g/10 minutes, the stress cracking resistance and impact resistance of the modified material of the present invention will deteriorate. Not necessarily enough.
The ratio of melt flow rate (MFR) to high load melt flow rate (HLMFR), that is, HLMFR/MFR, is 50 to 500, preferably 60 to 400, more preferably 70 to 300, and even more preferably 160 to 500. It is 200. When HLMFR/MFR is less than 50, there is no viscosity reduction at a predetermined shear rate, resulting in insufficient fluidity and the high-speed formability of the modified material of the present invention is reduced; Shrinkage anisotropy is more likely to occur.
In the present invention, MFR and HLMFR are values measured according to JIS-K6922-2:1997.

Characteristics (2)
The modified material made of polyethylene resin has a density of 0.955 g/cm ³ or more and 0.970 g/cm ³ or less, preferably 0.956 to 0.968 g/cm ³ , more preferably 0.958 to 0. .965g/ ^cm3 . If the density is less than 0.955 g/cm ³ , the rigidity of the modified material of the present invention decreases, making it difficult to make the container lid thinner, and it becomes easily deformed at high temperatures, causing the container lid to deform due to the influence of the internal pressure of the container. This may cause leakage. If the density exceeds 0.970 g/cm ³ , the stress cracking resistance of the modified material of the present invention is not necessarily sufficient.
In the present invention, the density of the polyethylene resin molding material is a value measured according to JIS-K6922-1, 2:1997.

Characteristics (3)
The modifier made of polyethylene resin has a rupture time (FNCT) at 80° C. and 1.9 MPa in a full notch creep test of 100 hours or more, more preferably 110 hours or more, and still more preferably 120 hours or more. The upper limit is not particularly limited, but is usually 1000 hours or less. If the FNCT is less than 100 hours, there is a high possibility that the container lid formed using the modified material of the present invention will break due to stress cracks during storage at high temperatures in summer. Here, FNCT is measured in accordance with JIS-K6774:1998 at a temperature of 80° C. using a 1% aqueous solution of Emar manufactured by Kao Corporation as a working liquid.

Characteristics (4)
The modified material made of polyethylene resin has a Charpy impact strength of 9.0 KJ/m ² or more, preferably 10 to 20 KJ/m ² , and more preferably 14 to 20 KJ/m ² . When the Charpy impact strength is less than 9.0 KJ/m ² , cracks are likely to occur in the container lid formed using the modified material of the present invention when the container is dropped after being filled with liquid. Charpy impact strength is measured in accordance with JIS-K7111-1:2006.

Characteristics (5)
The modifier made of polyethylene resin preferably has a flexural modulus of 900 to 1500 MPa, more preferably 950 to 1450 MPa. If the flexural modulus is less than 900 MPa, the rigidity decreases, and the container lid formed using the modified material of the present invention is likely to deform due to the internal pressure of the container, especially at high temperatures. Here, the flexural modulus is a value measured in accordance with JIS-K6922-2:1997 using a 4 x 10 x 80 mm plate body injection molded at 210°C as a test piece.

Characteristics (6)
The modifier made of polyethylene resin preferably has a melting viscosity of 200 to 1000 Pa·s, more preferably 250 to 600 Pa·s, and still more preferably 420 to 600 Pa·s at 190°C and a shear rate of 400 sec ^-1 . It is. If the melt viscosity is less than 200 Pa・s, the modifier of the present invention has excellent high fluidity, but the stress crack resistance and impact resistance of the container lid formed using the modifier decreases, and the fluidity and It is not possible to achieve both stress crack resistance and impact resistance. When the melt viscosity exceeds 1,000 Pa·s, fluidity decreases, resulting in a decrease in high-speed moldability.

Characteristics (7)
The modifier made of polyethylene resin preferably has a tensile yield strength of 25 MPa or more, preferably 26 MPa or more, and more preferably 27 MPa or more. When the tensile yield strength is less than 25 MPa, the bridge portion of the container lid formed using the modified material of the present invention has a poor cutting feel and lacks appropriate hardness. The upper limit of the tensile yield strength is not particularly limited, but is usually 50 MPa or less. Here, the tensile yield strength is a value measured in accordance with JIS-K6922-2:1997.
The tensile yield strength is correlated with the loosening of the container lid, and if the tensile yield strength is low, the container lid tends to loosen, and the container lid lacks proper hardness to close. In order to improve the stress crack resistance and impact resistance of container lids, it is necessary to lower the density of the polyethylene material, which makes it difficult to improve tensile yield strength while improving stress crack resistance and impact resistance. Met. However, according to the present invention, it is possible to improve the looseness, stress crack resistance, and impact resistance of the container lid.

Characteristics (8)
It is desirable that the modifying material made of polyethylene resin has a hydrocarbon volatile content of 80 ppm or less. The hydrocarbon volatile content is preferably 50 ppm or less, more preferably 30 ppm or less. The term "hydrocarbon" used in the present invention refers to a compound containing at least carbon and hydrogen in the molecule, and is usually measured by gas chromatography. It can prevent the effects of odor and flavor. Here, the hydrocarbon volatile content is determined by measuring the air in the head space using gas chromatography when 1 g of the modifier made of polyethylene resin is placed in a 25 ml glass sealed container and heated at 130°C for 60 minutes. can get.

(2) Composition of Modifier The modifier made of polyethylene resin is a composition of multiple types of ethylene polymers, and the following component (A) is 20% by mass or more and 40% by mass. Component (B) is contained in an amount of 60% by mass or more and 80% by mass or less. The modifier made of polyethylene resin may be composed of a single ethylene polymer, or may be composed of a composition of multiple types of ethylene polymers.
Component (A): HLMFR is 0.05 to 5.0 g/10 min, density is 0.910 to 0.935 g/cm ³ , ^and CSD ( Ethylene polymer with comonomer sequence distribution) value (CSD _A ) of 0.0 to 3.0 CSD=4×[EE][CC]/[EC] ² Formula (a)
(In formula (a), [EE] represents the number of ethylene/ethylene chains, [CC] represents the number of comonomer/comonomer chains, and [EC] represents the number of ethylene/comonomer chains.)
Component (B): Ethylene with a melt flow rate (MFR) of 100 g/10 minutes or more and less than 600 g/10 minutes at a temperature of 190°C and a load of 2.16 kg, and a density of 0.960 g/cm ³ or more and less than 0.980 g/cm ³ system polymer

In addition, MFR, HLMFR, and density are each measured by the said measuring method.
Further, the CSD (comonomer sequence distribution) of component (A) of the ethylene polymer is described in J. C. Randall, JMS-REV. MACROMOL. CHEM. PHYS. , C29 (2 & 3), pp. 201-317 (1989), and is measured by the ¹³ C-NMR spectrum of the ethylene polymer. Specifically, measurements were performed using a JEOL-GSX400 nuclear magnetic resonance apparatus manufactured by JEOL under the following conditions, and the above formula ( It can be determined by a).
Equipment: JEOL-GSX400 manufactured by JEOL, pulse width: 8.0 μsec (flip angle = 40°), pulse repetition time: 5 seconds, number of integrations: 5000 times or more, solvent and internal standard: 1,2,4-tri Chlorobenzene/benzene-d6/hexamethyldisiloxane (mixing ratio: 30/10/1), measurement temperature: 120°C, sample concentration: 0.3 g/ml After that, the spectrum obtained in the measurement is determined based on the following literature. be able to.
(1) In the case of ethylene/1-butene copolymer: Macromolecules, 15, 353-360 (1982) (Eric T. Hsieh and James C. Randall),
(2) In the case of ethylene/1-hexene copolymer: Macromolecules, 15, 1402-1406 (1982) (Eric T. Hsieh and James C. Randall)

In general, the CSD of ethylene polymers takes a value of 0 to ∞, but when the CSD value is high, the comonomer is inserted in a more block manner, and when the CSD value is low, the comonomer is inserted more alternately (or randomly). Indicates that the It can be said that the smaller the CSD, the better the composition distribution.

(2-1) Ethylene polymer as component (A) The ethylene polymer as component (A) has an HLMFR of 0.05 to 5.0 g/10 min, preferably 0.1 to 3.0 g/10 min. 10 minutes, more preferably 0.3 to 2.0 g/10 minutes. If the HLMFR of component (A) is less than 0.05 g/10 minutes, the fluidity of the modified material of the present invention tends to decrease and the moldability tends to be poor; There is a tendency for the stress crack resistance and impact resistance of the material to decrease.

The density of component (A) is 0.910 to 0.935 g/cm ³ , preferably 0.915 to 0.935 g/cm ³ , more preferably 0.918 to 0.932 g/cm ³ , even more preferably is 0.920 to 0.930 g/cm ³ . If the density of component (A) is less than 0.910 g/ ^cm3 , the rigidity of the modified material of the present invention will be insufficient, and if it exceeds 0.935 g/ ^cm3 , the stress crack resistance and resistance of the modified material of the present invention will be insufficient. Impact resistance tends to decrease.

Component (A) of the ethylene polymer has a CSD (comonomer sequence distribution) value CSD _A of 0.0 to 3.0 as measured by ¹³ C-NMR spectrum and determined by formula (a). It is preferably 0.0 to 2.5, more preferably 0.0 to 2.2.
When the CSD _A of component (A) is within the range of the present invention, that is, 0.0 to 3.0, the modified material of the present invention has an excellent balance of rigidity, stress crack resistance, and impact resistance. On the other hand, when CSD _A is larger than 3.0, it indicates that the composition distribution is wide, and the balance between rigidity, stress crack resistance, and impact resistance of the modified material of the present invention tends to deteriorate.
On the other hand, when the CSD _A of component (A) is larger than 3.0, it indicates that the composition distribution is wide, and the balance between the rigidity, stress crack resistance, and impact resistance of the modified material of the present invention decreases. . CSD is influenced by both intermolecular composition distribution and intramolecular composition distribution, and in Ziegler-Natta catalysts, the influence of intermolecular composition distribution is dominant, and the smaller the CSD value, the more comonomer copolymerization occurs between molecules. This suggests that there is little variation in the amount and a narrow composition distribution.
In the present invention, the smaller the value of CSD _A of component (A), the more preferable it ^is . This is because the amount of components that do not satisfy the desired density (number of short chain branches) is reduced, so the effect of improving the balance between the rigidity, stress crack resistance, and impact resistance of the modified material of the present invention is more likely to be expressed. .

The ethylene polymer of component (A) may be a polymer of ethylene alone, but is preferably a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and more preferably a copolymer of ethylene and 1-butene. A copolymer of ethylene and 1-hexene is preferred. The copolymerization ratio of the α-olefin having 3 to 20 carbon atoms is preferably 0.001 to 5.0 mol%.

(2-2) Ethylene polymer as component (B) The ethylene polymer as component (B) has an MFR of 100 g/10 minutes or more and less than 600 g/10 minutes, preferably 180 to 500 g/10 minutes, and Preferably it is 200 to 350 g/10 minutes. If the MFR of component (B) is less than 100 g/10 minutes, the fluidity of the modified material of the present invention tends to decrease and the moldability tends to be poor; Stress crack resistance and impact resistance tend to decrease.
The density of component (B) is 0.960 g/cm ³ or more and less than 0.980 g/cm ³ , preferably 0.965 to 0.975 g/cm ³ , more preferably 0.965 to 0.970 g/cm ³ . be. If the density of component (B) is less than 0.960 g/cm ³ , the rigidity of the modifier of the present invention may decrease, and if it is 0.980 g/cm ³ or more, it is difficult to manufacture.
The ethylene polymer of component (B) is preferably an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and more preferably an ethylene homopolymer or a copolymer of ethylene and 1-butene. Copolymers or copolymers of ethylene and 1-hexene are preferred. In the case of a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, the copolymerization ratio of the α-olefin having 3 to 20 carbon atoms is preferably 0.001 to 5.0 mol%.

In the present invention, the ratio of component (A) and component (B) is such that component (A) is 20% by mass or more and 40% by mass or less, and component (B) is 60% by mass or more and 80% by mass or less, and preferably component (A) is 20 to 35% by weight and component (B) is 65 to 80% by weight, more preferably component (A) is 20 to 30% by weight and component (B) is 70 to 80% by weight.
If component (A) is less than 20% by mass, the stress crack resistance and impact resistance of the modified material of the present invention will decrease, and if it exceeds 40% by mass, the moldability of the modified material of the present invention will tend to decrease. If component (B) is less than 60% by mass, the moldability of the modified material of the present invention will decrease, and if it exceeds 80% by mass, the stress crack resistance and impact resistance of the modified material of the present invention will tend to decrease. be. If it deviates from this range, any one or more of fluidity, rigidity, stress crack resistance, and impact resistance may be insufficient, resulting in poor performance balance.
In the present invention, the ethylene polymer may be composed of only component (A) and component (B), or may contain other arbitrary resin components.

(3) Other requirements for the composition of the modifier [Relationship between CSD and SCB of component (A)]
In the present invention, the ethylene polymer of component (A) has a CSD (comonomer sequence distribution) value (CSD _A ) determined by formula (a) from the measured value of ¹³ C-NMR spectrum, and ¹³ C- It is preferable that the number of short chain branches SCB _A having 1 to 20 carbon atoms per 1,000 carbon atoms in the main chain (number/1,000C), as measured by NMR spectrum, satisfies the following formula (b). More preferably, in the present invention, CSD _A and SCB _A satisfy the following formula (c). More preferably, the following formula (d) is satisfied.
CSD _A < -0.1273 × SCB _A +3.30 Formula (b)
CSD _A < -0.1273 × SCB _A +3.10 Formula (c)
CSD _A < -0.1273 × SCB _A +2.00 Formula (d)

In ethylene polymers, the CSD value is influenced by the number of short chain branches, and the smaller the number of short chain branches, the higher the number of ethylene chains, and the [CC] of [EE] in formula (a) Since the ratio to [EC] becomes higher, the value of CSD becomes higher. Therefore, even if the CSD value is the same, it can be said that the composition distribution is better as the number of short chain branches is smaller.

Here, if CSD _A and SCB _A satisfy the range of the present invention, that is, formula (b), they will be in the lower region of the line in Figure 1, but the rigidity, stress crack resistance, and resistance of the modified material of the present invention Excellent impact balance. On the other hand, when formula (b) is not satisfied, the region is above the linear line in Figure 1, which indicates that the composition distribution is wide, and the balance between stiffness, ESCR, and impact resistance of the modified material of the present invention is poor. It is on a declining trend.
The relational expression between CSD _A and SCB _A in the present invention is obtained by conveniently obtaining an approximate expression by using CSD _A as a function of SCB _A , and setting a preferable range of the polyethylene resin as the modifier. In the present invention, even if the modifier made of polyethylene resin satisfies the relational expression, the desired balance of properties as a modifier cannot be obtained unless other properties are satisfied.

In the present invention, in order to obtain a modifying material made of a polyethylene resin that satisfies the relational expression between CSD _A and SCB _A , it is important to control the insertion of comonomers, and various methods can be used. For example, the polymerization conditions and polymerization catalyst system are important factors, and known patent documents (JP-A-56-61406, JP-A-56-141304, JP-A-56-166206) , JP-A-57-141407, JP-A-60-235813, JP-A-61-246209) and solid catalysts obtained from specific magnesium compounds, titanium compounds, and organic aluminum halide compounds. This can be easily controlled by using a catalyst in combination with an organoaluminum compound.

[Shrinkage rate anisotropy (MD/TD)]
The modifier of the present invention preferably has a shrinkage anisotropy (MD/TD) of 1.0 or more and less than 2.5. MD/TD is preferably 1.0 or more and less than 2.3, and more preferably 1.1 or more and 2.2 or less. This value was obtained by forming a flat plate of 120 x 120 x 2 mm with a film gate on one side (gate thickness 0.2 mm) at a mold temperature of 190 °C and a mold temperature of 40 °C, and after molding, it was left at 23 °C for 48 hours. The shrinkage percentage in the subsequent machine direction (MD) and in the transverse direction (TD) is measured, and the value is the MD value divided by the TD value. If the shrinkage rate anisotropy (MD/TD) is 2.5 or more, the molded product is likely to crack, while if it is less than 1.0, the product is likely to be deformed. The shrinkage rate anisotropy (MD/TD) can be adjusted by controlling the molecular weight distribution.

3. Production of Modifying Material Made of Polyethylene Resin The ethylene polymer contained in the modifying material made of polyethylene resin can be produced by homopolymerization of ethylene alone or copolymerization of ethylene and α-olefin. The ethylene polymer contained in the modifying material made of polyethylene resin can be obtained by polymerizing it by ordinary one-stage polymerization, but it can also be obtained by mixing components polymerized under different conditions or by sequential multi-stage polymerization. It can also be manufactured.

(1) Production of a composition by mixing or sequential multi-stage polymerization The modifier made of polyethylene resin can be obtained by mixing the ethylene polymer of component (A) and the ethylene polymer of component (B). I can do it.
For reasons such as uniformity of the resin, it is preferable to sequentially polymerize the ethylene polymer of component (A) and the ethylene polymer of component (B) (sequential multistage polymerization method). For example, It can be obtained by sequentially and continuously polymerizing ethylene and α-olefin in a plurality of reactors connected in series.
In this case, an ethylene homopolymer is polymerized in one polymerization reactor, and a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is polymerized in the other polymerization reactor; It is possible to polymerize a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms in a reactor, and further copolymerize ethylene and an α-olefin having 3 to 20 carbon atoms in another polymerization reactor. , the former is preferred.
That is, in the present invention, at least one of the component (A) and the component (B) of the ethylene polymer is produced by multistage polymerization using a combination of at least two polymerization reactors in the presence of a polymerization catalyst. An ethylene homopolymer is polymerized in one of the polymerization reactors, and an ethylene copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is polymerized in at least the other of the two polymerization reactors. It is preferable that

Moreover, the composition consisting of component (A) and component (B) may be one obtained by polymerizing component (A) and component (B) separately and then mixing them. Furthermore, each of the ethylene polymers of component (A) and component (B) can be composed of a plurality of components. The ethylene polymer may be a polymer that is sequentially and continuously polymerized in a multi-stage polymerization reactor using one type of catalyst, or a polymer that is produced in a single-stage or multi-stage polymerization reactor using multiple types of catalysts. It may be a polymer that has been polymerized using one or more types of catalysts, or a mixture of polymers that have been polymerized using one or more types of catalysts.

(2) Polymerization method The ethylene polymer of component (A) and the ethylene polymer of component (B) can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, a slurry polymerization method, etc. Slurry polymerization is preferred. Among the polymerization conditions for the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300°C. In slurry polymerization, polymerization is carried out at a temperature lower than the melting point of the resulting polymer. Polymerization pressures can be selected from the range of atmospheric pressure to about 100 kg/cm ² . Selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, in a state where oxygen and moisture are substantially excluded. It can be preferably produced by slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

Hydrogen supplied to the polymerization vessel during slurry polymerization is consumed as a chain transfer agent and determines the average molecular weight of the produced ethylene polymer, and a portion is dissolved in a solvent and discharged from the polymerization vessel. The solubility of hydrogen in the solvent is low, and unless a large amount of gas phase exists in the polymerization vessel, the hydrogen concentration near the polymerization active site of the catalyst is low. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active site of the catalyst changes rapidly, and the molecular weight of the produced ethylene polymer changes in a short period of time following the hydrogen supply amount. Therefore, it is preferable to employ the slurry polymerization method as the polymerization method because a more homogeneous product can be produced by changing the hydrogen supply amount in a short cycle. Furthermore, although the manner in which the amount of hydrogen supplied may be changed continuously, it is better to change it discontinuously to obtain the effect of broadening the molecular weight distribution.
In the present invention, it is important to change the hydrogen supply amount during polymerization of the ethylene polymer, but other polymerization conditions such as polymerization temperature, catalyst supply amount, olefin supply amount such as ethylene, 1-butene It is also important to appropriately change the supply amount of comonomers such as, the supply amount of solvent, etc. simultaneously with or separately from changes in hydrogen.

(3) Sequential multistage polymerization In the so-called sequential multistage polymerization method, in which polymerization is carried out sequentially and continuously in multiple reactors connected in series, a high molecular weight component is produced in the first polymerization zone (first stage reactor), The obtained polymer may be transferred to the next reaction zone (second stage reactor) and a low molecular weight component may be produced in the second stage reactor, or the first polymerization zone (first stage reactor) A low molecular weight component is produced in the second reactor), the resulting polymer is transferred to the next reaction zone (second reactor), and a high molecular weight component is produced in the second reactor. Either method is fine.
A specific preferred polymerization method is the following method. That is, a Ziegler catalyst containing a titanium-based transition metal compound and an organoaluminum compound and at least two reactors are used, and ethylene and α-olefin are introduced into the first reactor to reduce the weight of low-density, high-molecular-weight components. The polymer extracted from the first-stage reactor is transferred to the second-stage reactor, and ethylene and hydrogen are introduced into the second-stage reactor to produce a high-density, low-molecular-weight polymer. This is a method for producing component polymers.
In the case of multi-stage polymerization, the amount and properties of the ethylene polymer produced in the polymerization zone from the second stage onward are determined by determining the amount of polymer produced in each stage (which can be determined by unreacted gas analysis), and The physical properties of the polymer extracted from each stage are measured, and the physical properties of the polymer produced at each stage can be determined based on the additivity.

(4) Polymerization Catalyst Various catalysts such as Ziegler catalysts, Phillips catalysts, and metallocene catalysts are used as polymerization catalysts for ethylene polymers. As the polymerization catalyst, any catalyst can be used as long as hydrogen exhibits a chain transfer effect in olefin polymerization. Specifically, any catalyst can be used as long as it is composed of a solid catalyst component and an organometallic compound and is suitable for slurry olefin polymerization in which hydrogen exhibits a chain transfer effect in olefin polymerization. Preferably, it is a heterogeneous catalyst in which the polymerization active sites are localized. The solid catalyst component is not particularly limited as long as it can be used as a solid catalyst for olefin polymerization containing a transition metal compound.

As the transition metal compound, compounds of metals from Groups IV to VIII of the periodic table, preferably from Groups IV to VI can be used, and specific examples include Ti, Zr, Hf, V, Examples include compounds such as Cr and Mo. An example of a preferred catalyst is a solid Ziegler catalyst comprising a compound of Ti and/or V and an organometallic compound of a metal from Group I to Group III of the Periodic Table. Furthermore, a combination of a cocatalyst and a complex in which a ligand having a cyclopentadiene skeleton is coordinated to a transition metal, called a metallocene catalyst, is exemplified. Specific metallocene catalysts include complex catalysts in which transition metals including Ti, Zr, Hf, lanthanide series, etc. are coordinated with ligands having a cyclopentadiene skeleton such as methylcyclopentadiene, dimethylcyclopentadiene, and indene. and organometallic compounds of metals from Groups I to III of the periodic table such as aluminoxane as a cocatalyst, and supported type catalysts in which these complex catalysts are supported on a carrier such as silica. It will be done. Particularly preferred solid catalyst components for olefin polymerization include those containing at least titanium and/or vanadium and magnesium.
As the organometallic compound that can be used with the solid catalyst component containing at least titanium and/or vanadium and magnesium, organoaluminum compounds, especially trialkylaluminum, are preferred. The amount of the organoaluminum compound used during the polymerization reaction is not particularly limited, but is usually preferably in the range of 0.05 to 1,000 mol per mol of the titanium compound.
More specifically, a Ziegler catalyst consisting of a solid catalyst component and an organoaluminum compound is preferred, and can be carried out particularly by using the catalyst and production method described in the following known literature. That is, JP-A-56-61406, JP-A-56-141304, JP-A-56-166206, JP-A-57-141407, JP-A-60-235813, and JP-A-Sho. It is preferable to polymerize the olefin using the catalyst system described in Japanese Patent No. 61-246209.
In the present invention, ^the polymerization catalyst for an ethylene polymer has the general formula Mg(OR ² ) _m X ² _2-m (wherein R ² represents an alkyl, aryl or cycloalkyl group, and , m is 1 or 2) and ^the compound represented by the general formula Ti(OR ³ ) _n X ³ _4-n (wherein, R ³ represents an alkyl, aryl or cycloalkyl group, and and n is 1, 2 or 3) is prepared from a homogeneous hydrocarbon solution containing a compound of general formula AlR ¹ _l X ¹ _3-l (wherein R ¹ is alkyl, aryl or cycloalkyl). a hydrocarbon-insoluble solid catalyst obtained by treatment with an organic aluminum halide compound represented by X ¹ represents a halogen atom, and l represents a number of 1≦l≦2; Preferred are catalyst systems comprising:

(5) Polymerizable monomer In the present invention, the ethylene polymer is a homopolymer of ethylene, or ethylene and an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4 -Methyl-1-pentene, 1-octene, etc., and in the case of copolymerization, 1-butene and 1-hexene are preferred monomers.
Copolymerization with dienes is also possible for the purpose of modification. Examples of diene compounds used at this time include butadiene, 1,4-hexadiene, ethylidenenorbornene, dicyclopentadiene, and the like.
The comonomer content during polymerization can be arbitrarily selected, but for example, in the case of copolymerization of ethylene and α-olefin having 3 to 12 carbon atoms, the comonomer content in the ethylene/α-olefin copolymer is The α-olefin content of is preferably 0.001 to 5.0 mol%.
As the raw material ethylene, ethylene derived from plants can be used for polymerization, and an ethylene polymer using this ethylene may be used.

4. Control method of characteristic values in modified material made of polyethylene resin (1) MFR and HLMFR
In the production of a modifier made of polyethylene resin, MFR and HLMFR can be adjusted to desired ranges by adjusting the temperature during polymerization of the ethylene monomer, the use of a chain transfer agent, and the like. That is, by increasing the polymerization temperature of ethylene and α-olefin, the molecular weight can be lowered, and as a result, MFR and HLMFR can be increased. By lowering the polymerization temperature, the molecular weight can be increased, and as a result, MFR and HLMFR can be decreased. can do. In addition, in the copolymerization reaction of ethylene and α-olefin, by increasing the amount of hydrogen coexisting (the amount of chain transfer agent), the molecular weight can be lowered, and as a result, MFR and HLMFR can be increased. By decreasing (the amount of chain transfer agent), the molecular weight can be increased, and as a result, MFR and HLMFR can be decreased.

(2) HLMFR/MFR
In the production of a modifier made of polyethylene resin, HLMFR/MFR (flow ratio FLR) can be increased or decreased by adjusting the molecular weight distribution. This HLMFR/MFR is correlated with the monodispersity of molecular weight (mass average molecular weight Mw/number average molecular weight Mn) determined by gel permeation chromatography, and 100 of HLMFR/MFR corresponds to about 18 of monodispersity Mw/Mn. do. HLMFR/MFR or Mw/Mn can be adjusted by adjusting the type of catalyst, type of promoter, polymerization temperature, residence time in the polymerization reactor, number of polymerization reactors, etc., and can also be adjusted by adjusting the temperature, pressure, and shear stage of the extruder. It can be adjusted by adjusting the speed, etc., and preferably can be increased or decreased by adjusting the mixing ratio of high molecular weight components and low molecular weight components.
The HLMFR/MFR or Mw/Mn of ethylene polymers is easily affected by the type of catalyst; in general, Phillips catalysts have a wide molecular weight distribution, metallocene catalysts have a narrow molecular weight distribution, and Ziegler catalysts have a narrow molecular weight distribution. This results in a polymer with an intermediate molecular weight distribution.

(3) Density In the production of a modifier made of polyethylene resin, the density can be adjusted to a desired range by changing the type and amount of comonomer copolymerized with ethylene.

(4) CSD
In a modified material made of polyethylene resin, when the CSD value of component (A) is high, the comonomer is inserted in a more block manner, and when the CSD value is low, the comonomer is inserted more alternately (or randomly). ing. Controlling the insertion of comonomers has undergone repeated technological innovations in the field of polyolefin polymerization, and various methods are available, but for the modifying material made of polyethylene resin used in the present invention, the catalyst system for polymerization is important. It is one of the elements, and is one of the known patent documents described above (JP-A-56-61406, JP-A-56-141304, JP-A-56-166206, JP-A-57-141407). A solid catalyst obtained from a specific magnesium compound, titanium compound, or organic aluminum halide compound described in Japanese Patent Application Laid-Open No. 60-235813, Japanese Patent Application Laid-open No. 61-246209) and an organic aluminum compound are combined. It can be easily controlled by using a catalyst.

(5) SCB (number of short chain branches with 1 to 20 carbon atoms per 1,000 carbon atoms in the main chain)
In the production of a modifier made of polyethylene resin, the number of short chain branches can be adjusted to a desired range by changing the type and amount of comonomer copolymerized with ethylene. The number of short chain branches is correlated with density; for example, at a density of 0.916 g/cm ³ it is approximately 14 pieces/1,000C, and at a density of 0.930 g/cm ³ it is approximately 4 pieces/1,000C.

(6) Control of other characteristic values In the production of modified materials made of polyethylene resin, in order to increase the time to rupture (FNCT) at 80°C and 1.9 MPa in the full notch creep test, it is necessary to use low density and high molecular weight components. This can be achieved by adding.
ESCR can be achieved by adjusting the density, molecular weight, and molecular weight distribution and appropriately using the low density and high molecular weight component of component (A) in the present invention.
The Charpy impact strength can be increased by lowering the high load melt flow rate (HLMFR), lowering the density, etc.

The flexural modulus can be adjusted by increasing or decreasing the molecular weight and density of the polyethylene; increasing the molecular weight or density can increase the flexural modulus.
The melt viscosity at 190° C. and a shear rate of 400 sec ⁻¹ can be adjusted by increasing or decreasing the molecular weight and density of polyethylene, and increasing the molecular weight can increase the melt viscosity.
The tensile yield strength can be adjusted by increasing or decreasing the density, and can be increased by increasing the density.
In order to reduce the hydrocarbon volatile content to a predetermined value or less, the polymerized polyethylene polymer is subjected to a volatile content removal operation, such as steam stripping treatment, hot air deodorization treatment, vacuum treatment, nitrogen purge treatment, etc. This control operation can be achieved particularly by performing steam deodorization treatment. Although the conditions for the steam treatment are not particularly limited, it is preferable to contact the ethylene polymer with steam at 100° C. for about 8 hours.

5. Amount of Modifier Made of Polyethylene Resin In the present invention, the content of the modifier is appropriately adjusted within the range of 1 to 99% by mass based on the total amount of the recovered polyolefin resin and the modifier. In order to improve the durability (stress crack resistance) of polyolefin-based recovered resin recycled from PET bottle caps collected in the market to the level of PET bottle cap products for non-carbonated beverages, the performance of the recovered polyolefin-based resin is important. It is necessary to add an appropriate amount of modifier according to the If the performance of the recovered polyolefin resin is high, only a small amount of modifier is required, but if the performance is low, the amount of modifier required is large.
The amount of the modifying material is determined to improve the durability (stress crack resistance) of the recovered polyolefin resin recycled from PET bottle caps collected in the market without impairing the rigidity of the recovered polyolefin resin during modification. The bending elastic modulus, which indicates the rigidity of the resulting polyolefin resin molding material, and the durability (stress crack resistance) of the polyolefin resin molding material are shown, from the perspective of improving it to a level that can be used as a PET bottle cap product for beverages. It is preferable to adjust the environmental stress cracking resistance (ESCR) so that both of them are high in a well-balanced manner.
Specifically, the flexural modulus of the polyolefin resin molding material is preferably 900 MPa or more, more preferably 950 MPa or more, or the environmental stress cracking resistance (ESCR) of the polyolefin resin molding material is preferably The amount of the modifier is adjusted so that the heating time is 45 hours or more, more preferably 50 hours or more.
In many cases, the amount of the modifier is preferably 10% by mass or more, based on the total amount of the modifier consisting of recovered polyolefin resin and polyethylene resin obtained from PET bottle caps collected on the market. By setting the content to 20% by mass or more, more preferably 30% by mass or more, performance at a level that can be used for PET bottle cap products for non-carbonated beverages can be obtained.
In addition, the performance of the resulting polyolefin resin molding material improves as the amount of the modifier made of polyethylene resin increases, so the upper limit of the amount of the modifier is not particularly limited. Even if the amount of the modifier is limited to 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, with respect to the total amount of the modifier consisting of recovered resin and polyethylene resin, The amount is sufficient to obtain a usable level of performance for PET bottle cap products for non-carbonated beverages.

6. Manufacture of polyolefin resin molding material The polyolefin resin molding material of the present invention contains the above-mentioned recovered polyolefin resin and a modifier made of the above-mentioned polyethylene resin as essential components, and further contains other components as necessary. It can be obtained by uniformly mixing according to a conventional method for producing compositions.
For example, pellets of the recovered polyolefin resin and pellets of the modifier may be dry-blended or melt-blended, and other components may be added in any order during the blending. In the case of dry blending, pellets of the recovered polyolefin resin and pellets of the modifier are finally melt-blended in a molding machine. The blending method is appropriately selected depending on the manufacturing process. In the case of melt blending, the obtained polyolefin resin molding material may be pelletized by processing with a pelletizer.

In order to further enhance various physical properties or add other physical properties, polymers other than olefins may be blended into the polyolefin resin molding material of the present invention, and antioxidants ( (phenols, phosphorus, sulfur), ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, antifogging agents, antiblocking agents, processing aids, colored pigments, crosslinking agents, blowing agents, inorganic or organic fillers , a flame retardant, a nucleating agent that accelerates the crystallization rate, and other additives may be added.

The polyolefin resin molding material of the present invention preferably has a high content ratio of the modifier made of the recovered polyolefin resin and the polyethylene resin, from the viewpoint of imparting properties suitable as a PET bottle cap for non-carbonated beverages. Specifically, the total amount of the modified material consisting of the recovered polyolefin resin and the polyethylene resin is preferably 90% by mass or more, and preferably 95% by mass or more of the entire polyolefin resin molding material. is more preferable, and even more preferably 97% by mass or more.

7. Molding using polyolefin resin molding material The polyolefin resin molding material of the present invention satisfies various properties, so it has excellent moldability, high fluidity, odor, impact resistance, food safety, rigidity, etc., and is heat resistant. Excellent in sex. Therefore, it is suitable for applications such as containers and container lids that require such characteristics.
In particular, PET bottle caps for non-carbonated beverages can be manufactured by molding using the polyolefin resin molding material of the present invention by injection molding, compression molding, or the like. The PET bottle cap for non-carbonated beverages is preferably manufactured by continuous compression molding.
In addition, the polyolefin resin molding material of the present invention can be used for containers and container lids for foods and beverages such as edible oils, spices such as wasabi, seasonings, and alcoholic beverages, and containers and container lids for cosmetics and hair creams. It can be used and is mainly molded by injection molding method.

The present invention will be explained in more detail in the following Examples and Comparative Examples, but the present invention is not limited thereto.

[Measurement method and evaluation method]
The measurement methods and evaluation methods used in Examples and Comparative Examples are as follows.
(1) Melt flow rate (MFR) at a temperature of 190° C. and a load of 2.16 kg: Measured in accordance with JIS-K6922-2:1997.
(2) High load melt flow rate (HLMFR) at a temperature of 190° C. and a load of 21.6 kg: Measured in accordance with JIS-K6922-2:1997.
(3) Density: Measured according to JIS-K6922-1, 2:1997.

(4) Comonomer sequence distribution (CSD _A ): The CSD (CSD _A ) of component (A) of the modifier made of polyethylene resin was determined by J. C. Randall, JMS-REV. MACROMOL. CHEM. PHYS. , C29 (2 ^& 3), pp. 201-317 (1989). Specifically, the number of ethylene/ethylene chains, the number of comonomer/comonomer chains, and the number of ethylene/comonomer chains were measured using a JEOL-GSX400 nuclear magnetic resonance apparatus manufactured by JEOL. From these values, CSD _A was calculated using the formula ( Determined by a).
CSD=4×[EE][CC]/[EC] ² formula (a)

In addition, specifically, the measurement was performed under the following conditions.
Equipment: JEOL-GSX400 manufactured by JEOL, pulse width: 8.0 μsec (flip angle = 40°), pulse repetition time: 5 seconds, number of integrations: 5000 times or more, solvent and internal standard: 1,2,4-tri Chlorobenzene/benzene-d6/hexamethyldisiloxane (mixing ratio: 30/10/1), measurement temperature: 120°C, sample concentration: 0.3 g/ml. In addition, the spectrum obtained in the measurement was determined based on the following literature.
(i) In the case of ethylene/1-butene copolymer: Macromolecules, 15, 353-360 (1982) (Eric T. Hsieh and James C. Randall),
(ii) In the case of ethylene/1-hexene copolymer: Macromolecules, 15, 1402-1406 (1982) (Eric T. Hsieh and James C. Randall)

(5) Number of short chain branches with 1 to 20 carbon atoms per 1,000 carbon atoms in the main chain SCB _A :
The ¹³ C-NMR spectrum of component (A) of the modifier made of polyethylene resin was measured under the same conditions as the ¹³ C-NMR spectrum used to calculate the CSD, and was determined based on the following literature.
(i) In the case of ethylene/1-butene copolymer: Macromolecules, 15, 353-360 (1982) (Eric T. Hsieh and James C. Randall),
(ii) In the case of ethylene/1-hexene copolymer: Macromolecules, 15, 1402-1406 (1982) (Eric T. Hsieh and James C. Randall)

(6) Fracture time (FNCT) at 1.9 MPa by full notch creep test: Measured in accordance with JIS-K6774:1998 at a temperature of 80° C. using a 1% aqueous solution of detergent Emal manufactured by Kao Corporation as the working liquid.
(7) Charpy impact strength: Measured in accordance with JIS-K7111-1:2006.
(8) Flexural modulus: Measured in accordance with JIS-K6922-2:1997 using a 4 mm x 10 mm x 80 mm plate body injection molded at 210° C. as a test piece.

(9) Melt viscosity: Melt viscosity was measured using a capillary rheometer manufactured by Intesco at a shear rate of 400 sec ^-1 at 190° C. using a capillary with a diameter of 1 mm and L/D: 35.
(10) ESCR: Measured in accordance with ASTM D 1693 at a temperature of 50° C. using a 10 vol % aqueous solution of IGEPAL CO-630 manufactured by SIGMA-ALDRICH as the working liquid.
(11) Comprehensive evaluation of polyolefin resin molding material The compatibility of the polyolefin resin molding material with PET bottle caps for non-carbonated beverages was evaluated using the following evaluation criteria.
[Evaluation criteria]
○ (Good): Flexural modulus is 900 MPa or more and ESCR is 45 hours or more.
× (Poor): Flexural modulus is less than 900 MPa, or ESCR is less than 45 hours.

[Preparation of modified material A]
(Manufacture of catalyst)
115 g of magnesium ethoxide, 151 g of tri-n-butoxymonochlorotitanium, and 37 g of n-butanol were mixed at 150° C. for 6 hours and homogenized. Next, the temperature was lowered to 60°C, and n-hexane was added to form a homogeneous solution. Next, 457 g of ethylaluminum sesquichloride was added dropwise at a predetermined temperature and stirred for 1 hour. By washing the generated precipitate with n-hexane, 210 g of the catalyst component was obtained. The obtained solid was dried and powdered. This powder contained 11.0% by mass of Mg and 10.5% by mass of Ti.

(Production of polymer)
1.5 g/hr of the solid catalyst component obtained in the above (catalyst production) was fed from the catalyst supply line to the first stage polymerization vessel with an internal volume of 200 liters as the first stage reactor, and triethyl While supplying 40 mmol/hr of aluminum and discharging the polymerized contents at the required rate, at 70°C, polymerization solvent (n-hexane) 70 (l/hr), hydrogen 209 (mg/hr), ethylene 17.3 (kg) /hr) and 1-butene at a rate of 0.59 (kg/hr), and the first stage copolymerization was carried out continuously under conditions of a total pressure of 1.4 MPa and an average residence time of 2.2 hr.
A portion of the polymerization product from the first-stage reactor was sampled, and the polymerized product was recovered and its physical properties were measured, and the results were designated as "component (A)."
The entire slurry polymerization product produced in the first stage reactor was directly introduced into the second stage reactor with an internal volume of 400 liters through a continuous tube with an inner diameter of 50 mm, and while discharging the contents of the polymerization vessel at the required speed, Polymerization solvent (n-hexane) was supplied at a rate of 100 (l/hr), hydrogen 30.2 (g/hr), and ethylene 42.8 (kg/hr) at 82°C, total pressure 1.1 MPa, average The second stage polymerization was carried out continuously under conditions of a residence time of 1.71 hr.
The polymerization product discharged from the second stage reactor was introduced into a flushing tank, the polymerization product was continuously extracted, and unreacted gas was removed from the degassing line. After the obtained polymer was subjected to a steam stripping treatment and granulated using a pelletizer, its physical properties were evaluated.
Modified material A obtained by the above method met the requirements for a modified material used in the present invention. The results are shown in Table 1 below.
In Table 1, the physical properties of "component (B)" produced in the second stage reactor are the physical properties of the final product polyethylene composition and the physical properties of component (A) obtained in the first stage reactor. It was obtained by calculation based on the additivity rule.

[Example 1]
Recycled pellets from Shinei Kasei Co., Ltd. (MFR: 1.4 g/10 min, HLMFR: 147 g/10 min, HLMFR/MFR: 105, density : 0.965 g/cm ³ , FNCT: 23 hours, Charpy impact strength: 8 KJ/m ² , flexural modulus: 1050 PMa, ESCR: 30 hours) and the above modified material A (MFR: 0.8 g/10 minutes). , HLMFR: 130g/10min, HLMFR/MFR: 162.5, density: 0.962g/cm ³ , FNCT: 170 hours, Charpy impact strength: 11KJ/m ² , flexural modulus: 1000PMa, ESCR: 250 hours) After dry-blending the pellets at a mass ratio of 60:40 (polyolefin recovered resin:modifying material), a Laboplastomill manufactured by Toyo Seiki Co., Ltd. (type: roller mixer R100 type) equipped with a small mixer with a capacity of 100 ml was used. 70g was added to At the same time, 0.14 g of antioxidant B225 was added, preheated at 190°C for 3 minutes, and then kneaded at 190°C and 40 rpm for 2 minutes to perform melt blending.
The physical properties of the obtained resin molding material are MFR: 1.1 g/10 min, HLMFR: 137 g/10 min, HLMFR/MFR: 125, density: 0.964 g/cm ³ , Charpy impact strength: 9 KJ/m ² , flexural modulus: 1020 PMa, and ESCR: 83 hours, which were physical property values that could be used as a PET bottle cap for non-carbonated beverages.

[Example 2]
The test was conducted in the same manner as in Example 1, except that the mass ratio of the recovered polyolefin resin and the modifier was changed to 20:80.
The physical properties of the obtained resin molding material are MFR: 0.8 g/10 min, HLMFR: 132 g/10 min, HLMFR/MFR: 165, density: 0.963 g/cm ³ , Charpy impact strength: 10 KJ/m ² , flexural modulus: 1000 PMa, and ESCR: 150 hours, which were physical property values that could be used as a PET bottle cap for non-carbonated beverages.

[Comparative example 1]
Recycled pellets from Shinei Kasei Co., Ltd. used in Example 1 were used as polyolefin-based recovered resin recycled from PET bottle caps collected in the market, and recycled pellets from Japan Polyethylene Co., Ltd. for general injection molding were used as modifying materials. Grade polyethylene resin HJ560 (MFR: 7.1 g/10 min, HLMFR: 227 g/10 min, HLMFR/MFR: 32, density: 0.964 g/cm ³ , FNCT: 15 hours, Charpy impact strength: 6 KJ/m ² , flexural modulus: 1200 MPa, ESCR: 21 hours) pellets were dry-blended at a mass ratio of 60:40 (polyolefin-based recovered resin:modifying material), and then the pellets were dry-blended using a Toyo Seiki machine equipped with a small mixer with a capacity of 100 ml. 70 g of the mixture was put into a Labo Plastomill (type: roller mixer R100 type) manufactured by Co., Ltd. At the same time, 0.14 g of antioxidant B225 was added, preheated at 190°C for 3 minutes, and then kneaded at 190°C and 40 rpm for 2 minutes to perform melt blending.
The physical properties of the obtained resin molding material are: MFR: 3.7 g/10 min, HLMFR: 185 g/10 min, HLMFR/MFR: 50, density: 0.965 g/cm ³ , Charpy impact strength: 7 KJ/m ² , flexural modulus: 1080 MPa, ESCR: 25 hours, and because the durability (stress crack resistance) shown by ESCR is insufficient, it cannot be used as a PET bottle cap for non-carbonated beverages.

[Comparative example 2]
Recycled pellets from Shinei Kasei Co., Ltd. used in Example 1 were used as the polyolefin-based recovered resin recycled from PET bottle caps collected in the market, and plastomer grade from Japan Polyethylene Co., Ltd. was used as the modifying material. Polyethylene resin KS571 (MFR: 12 g/10 min, HLMFR: no data, HLMFR/MFR: no data, density: 0.907 g/cm ³ , FNCT: 500 hours or more, Charpy impact strength: too soft to break, bend After dry blending the pellets (modulus of elasticity: 110 MPa, ESCR: 1000 hours or more) at a mass ratio of 80:20 (polyolefin recovered resin: modifier), a small mixer with a capacity of 100 ml was attached to the pellets manufactured by Toyo Seiki Co., Ltd. 70 g of the mixture was put into a Labo Plastomill (type: roller mixer R100 type) manufactured by Co., Ltd. At the same time, 0.14 g of antioxidant B225 was added, preheated at 190°C for 3 minutes, and then kneaded at 190°C and 40 rpm for 2 minutes to perform melt blending.
The physical properties of the obtained resin molding material are: MFR: 1.8 g/10 min, HLMFR: 170 g/10 min, HLMFR/MFR: 94, density: 0.953 g/cm ³ , flexural modulus: 700 MPa, ESCR: Although the durability (stress crack resistance) shown by ESCR was good for 140 hours, the rigidity shown by flexural modulus was significantly reduced, making it suitable for PET bottle caps for non-carbonated beverages. It wasn't.

[result]
The properties of Modifier A used in Examples 1 and 2, Modifier HJ560 used in Comparative Example 1, and Modifier KS571 used in Comparative Example 2 are shown in Table 1 below.
In addition, the properties of the recovered polyolefin resin and modified material used in each Example and Comparative Example, and the modified polyolefin resin molding material obtained in each Example and Comparative Example are shown in Table 2 below. .
The modifier used in Examples 1 and 2 is a polyethylene resin that is composed of the above-mentioned specific components (A) and (B) and satisfies characteristics (1) to (4), and has a flexural modulus of elasticity. The resin molding materials obtained in Examples 1 and 2 are excellent in various physical properties required for PET bottle caps, including rigidity expressed by FNCT and durability expressed by FNCT. To improve the durability (stress crack resistance) to the level required for ordinary PET bottle cap products for non-carbonated beverages without lowering the physical properties of the resin from the level required for PET bottle caps. was completed.
On the other hand, the modified material used in Comparative Example 1 does not consist of component (A) and component (B) and has a low FNCT, so the ESCR of the resin molding material obtained in Comparative Example 1 is also low. , durability (stress crack resistance) was insufficient.
In addition, the modifier used in Comparative Example 2 does not consist of component (A) and component (B) and has a low flexural modulus, so the flexural modulus of the resin molding material obtained in Comparative Example 2 is The stiffness also decreased significantly.

Claims (9)

Contains polyolefin-based recovered resin obtained by homogenizing market recovered products of polyolefin-based resin caps of PET bottles, and a modifying material made of the following polyethylene-based resin,
A polyolefin resin molding material in which the content of the modifier is 1 to 99% by mass based on the total amount of the recovered polyolefin resin and the modifier.
[Modified material made of polyethylene resin]
The ethylene polymer contains the following component (A) in an amount of 20% by mass or more and 40% by mass or less, and component (B) in an amount of 60% by mass or more and 80% by mass or less, and has the following properties (1) to (4). A modified material made of polyethylene resin that satisfies the requirements.
Component (A): HLMFR is 0.05 to 5.0 g/10 min, density is 0.910 to 0.935 g/cm ³ , and determined by formula (a) from the measured value of ¹³ C-NMR spectrum. Ethylene polymer with CSD (comonomer sequence distribution) value (CSD _A ) of 0.0 to 3.0 CSD = 4 × [EE] [CC] / [EC] ² formula (a)
(In formula (a), [EE] represents the number of ethylene/ethylene chains, [CC] represents the number of comonomer/comonomer chains, and [EC] represents the number of ethylene/comonomer chains.)
Component (B): Ethylene polymer with MFR of 100 g/10 min or more and less than 600 g/10 min, density of 0.960 g/cm ³ or more and less than 0.980 g/cm ³ Characteristics (1): Temperature 190°C/Load 2 .The melt flow rate (MFR) at 16 kg is 0.2 g/10 minutes or more and 3.0 g/10 minutes or less, and the high load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is 70 g/10 minutes or more and 180 g. /10 minutes, and HLMFR/MFR is 50 to 500 Characteristic (2): Density is 0.955 g/cm ³ or more and 0.970 g/cm ³ or less Characteristic (3): 80 by full notch creep test ℃, 1.9 MPa rupture time (FNCT) is 100 hours or more Characteristic (4): Charpy impact strength is 9.0 KJ/m ² or more The polyolefin resin molding material according to claim 1, wherein the polyolefin resin molding material has a flexural modulus of 900 MPa or more. The polyolefin resin molding material according to claim 1 or 2, wherein the polyolefin resin molding material has an environmental stress cracking resistance (ESCR) of 45 hours or more. The polyolefin resin molding material according to any one of claims 1 to 3, wherein the modifier made of the polyethylene resin further satisfies the following characteristics (5) to (6).
Characteristic (5): Flexural modulus is 900 to 1,500 MPa Characteristic (6): Melting viscosity at 190°C and shear rate of 400 sec ^-1 is 200 to 1,000 Pa・s At least one of component (A) and component (B) of the ethylene polymer is polymerized by multistage polymerization using a combination of at least two polymerization reactors in the presence of a polymerization catalyst. An ethylene homopolymer is polymerized in a reactor, and an ethylene copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is polymerized in at least another of the two polymerization reactors. The polyolefin resin molding material according to any one of claims 1 to 4, characterized in that it is a polyolefin resin molding material. The polymerization catalyst for the ethylene polymer has ^the general formula Mg(OR ² ) _m X ² _2-m (wherein R ² represents an alkyl, aryl, or cycloalkyl group, ¹ or 2) and the compound represented by the general formula Ti(OR ³ ) _n X ³ _4-n (wherein R ³ represents an alkyl, aryl or cycloalkyl group, and A homogeneous hydrocarbon solution containing a compound of the general formula AlR ¹ _l X ¹ _3-l (wherein R ¹ represents an alkyl, aryl or cycloalkyl group) , X ¹ represents a halogen atom, l represents a number of 1≦l≦2) A catalyst containing a hydrocarbon-insoluble solid catalyst obtained by treatment with an organic aluminum halide compound and an organic aluminum compound. The polyolefin resin molding material according to claim 5, characterized in that: The polyolefin resin molding material according to any one of claims 1 to 6, which is used for molding a PET bottle cap for non-carbonated beverages. The polyolefin resin molding material according to any one of claims 1 to 6, which is used for continuous compression molding of PET bottle caps for non-carbonated beverages. A PET bottle cap for non-carbonated beverages formed by molding the polyolefin resin molding material according to any one of claims 1 to 6.