Polyolefin resin molding materials and PET bottle caps for non-carbonated beverages

Abstract

This invention provides a polyolefin resin molding material with improved durability, which is obtained by homogenizing PET bottle caps collected from the market using a material recycling method, and a PET bottle cap for non-carbonated beverages molded using the same. [Solution] A polyolefin-based resin molding material comprising a polyolefin-based recovered resin obtained by homogenizing market-recovered resin caps for PET bottles, and a modifier made of a specific polyethylene-based resin, wherein the content of the modifier is 1 to 99% by mass of the total amount of the polyolefin-based recovered resin and the modifier, and a PET bottle cap for non-carbonated beverages formed by molding the polyolefin-based resin molding material.

Description

[Technical Field]

[0001] The present invention relates to a polyolefin resin molding material, and more particularly to a polyolefin resin molding material suitable for lids of containers that hold liquids such as soft drinks, especially non-carbonated beverages. The invention relates to a recycled polyolefin resin molding material obtained by modifying a polyolefin-based recovered resin obtained by homogenizing market-collected PET bottle caps using a material recycling method, and to a PET bottle cap for non-carbonated beverages molded using the said polyolefin resin molding material. [Background technology]

[0002] Plastic containers, particularly PET (polyethylene terephthalate) bottles, have seen a significant increase in demand as containers for soft drinks and other beverages since their approval as such, due to their excellent mechanical strength, transparency, high gas shielding properties, and non-polluting characteristics. Small PET bottles, in particular, are widely used by consumers as portable beverage containers. Furthermore, improvements in the heat and pressure resistance of PET bottles have led to their widespread use as containers for hot beverages for winter use and for high-temperature sterilized beverages for long-term storage.

[0003] Furthermore, while PET containers for soft drinks such as carbonated beverages traditionally used metal lids made of aluminum or other materials, polyolefin lids are now widely used due to economic reasons. For containers for soft drinks and similar beverages, airtightness, ease of opening, food and beverage safety, and durability are essential performance requirements. In addition to these performance requirements, technical improvements to polyethylene resin lid components are being continuously studied from the perspective of various physical properties such as moldability, rigidity, and heat resistance, and a great many improvements have been proposed.

[0004] Regarding polyethylene-based resin molding materials suitable for PET bottle caps for carbonated beverages, there is a known polyethylene-based resin molding material that is generally excellent in terms of high-speed moldability, high fluidity, rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, ease of opening, ease of closing, etc., and also exhibits good long-term durability even at high temperatures, and is particularly suitable for container lids with improved Charpy impact strength (Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-151181 [Overview of the project] [Problems that the invention aims to solve]

[0006] While PET bottle caps made of polyethylene resin have become widespread and widely used, in recent years, environmental and recycling considerations have become increasingly important for resin products, given the problems of plastic waste and the importance of carbon neutrality. As a result, there is a strong demand for PET bottle caps to be recycled and utilized as plastic resources rather than being used as single-use disposable items.

[0007] While recycling efforts, such as separate collection, are widespread for PET bottle caps, and efforts are being made to effectively utilize resources, the PET bottle caps collected from the market are a collection of products with diverse physical properties ranging from high to low performance. As a result, there are problems in terms of performance, particularly durability (stress crack resistance), making it difficult to recycle them as PET bottle caps as they are.

[0008] In view of the circumstances of the prior art, the present invention aims to provide a recycled polyolefin resin molding material, and a PET bottle cap for non-carbonated beverages molded using the modified polyolefin resin molding material, which is obtained by homogenizing PET bottle caps collected from the market using a material recycling method, thereby improving the durability (stress crack resistance) of the polyolefin resin to a level that can be used for ordinary PET bottle cap products for non-carbonated beverages. [Means for solving the problem]

[0009] To solve the above problems, the inventors conducted extensive research and found that by adding the polyethylene resin molding material suitable for PET bottle caps for carbonated beverages, as described in Patent Document 1, as a modifier to polyolefin resin recycled by crushing and homogenizing PET bottle caps collected from the market, the durability (stress crack resistance) of the polyolefin resin recycled from PET bottle caps collected from the market can be improved to a level suitable for use as a PET bottle cap product for non-carbonated beverages, without impairing the rigidity of the polyolefin resin during the modification process.

[0010] The first invention of this invention includes a polyolefin-based recovered resin obtained by homogenizing market-recovered polyolefin-based resin caps for PET bottles, and a modifying material consisting of the following polyethylene-based resin. This is a polyolefin-based resin molding material in which the content of the modifier is 1 to 99% by mass relative to the total amount of the polyolefin-based recovered resin and the modifier. [Modifier made from polyethylene resin] A modifying material made of polyethylene resin that contains 20% to 40% by mass of component (A) and 60% to 80% by mass of component (B) as an ethylene polymer, and satisfies the following characteristics (1) to (4). Components (A): HLMFR 0.05-5.0 g / 10 min, density 0.910-0.935 g / cm³ 3 and13 The value of CSD (comonomer sequence distribution) determined by formula (a) from the measured values of the 13C-NMR spectrum (CSD A ) is an ethylenic polymer 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): An ethylenic polymer having an MFR of 100 g / 10 min or more and less than 600 g / 10 min and a density of 0.960 g / cm 3 or more and less than 0.980 g / cm 3 Characteristic (1): The melt flow rate (MFR) at a temperature of 190 °C and a load of 2.16 Kg is 0.2 g / 10 min or more and 3.0 g / 10 min or less, the high load melt flow rate (HLMFR) at a temperature of 190 °C and a load of 21.6 Kg is 70 g / 10 min or more and less than 180 g / 10 min, and HLMFR / MFR is 50 to 500 Characteristic (2): The density is 0.955 g / cm 3 or more and 0.970 g / cm 3 or less Characteristic (3): The fracture time (FNCT) at 80 °C and 1.9 MPa by the full notch creep test is 100 hours or more Characteristic (4): The Charpy impact strength is 9.0 KJ / m 2 or more

[0011] The second invention of the present invention is characterized in that, in the first invention, the flexural modulus of the polyolefin resin molding material is 900 MPa or more. <~

[0012] The third invention of the present invention is characterized in that, in the first or second invention, the environmental stress crack resistance (ESCR) of the polyolefin resin molding material is 45 hours or more.

[0013] The fourth invention of the present invention is characterized in that, in the first to third inventions, the modifier made of polyethylene resin further satisfies the following characteristics (5) to (6). Characteristic (5): The flexural modulus is 900-1500 MPa. Characteristics (6): 190°C, shear rate 400 sec -1 The viscosity at melting is 200-1000 Pa·s.

[0014] The fifth invention of the present invention is characterized in that, in the first to fourth inventions, at least one of the ethylene polymer components (A) and (B) is obtained by multi-stage polymerization combining at least two polymerization reactors in the presence of a polymerization catalyst, wherein an ethylene homopolymer is polymerized in at least one of the two 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.

[0015] The sixth invention of this invention is that, in the fifth invention, the polymerization catalyst for the ethylene polymer is of the general formula Mg(OR 2 ) m X 2 2-m (In the formula, R 2 X represents alkyl, aryl, or cycloalkyl groups. 2 Compounds represented by the general formula Ti(OR) (where m is 1 or 2, where m represents a halogen atom) and 3 ) n X 3 4-n (In the formula, R 3 X represents alkyl, aryl, or cycloalkyl groups. 3 A homogeneous hydrocarbon solution containing a compound represented by the general formula AlR (where is a halogen atom and n is 1, 2, or 3), 1 l X 1 3-l (In the formula, R 1 X represents alkyl, aryl, or cycloalkyl groups. 1The catalyst is characterized by comprising a hydrocarbon-insoluble solid catalyst obtained by treatment with an organic aluminum halide compound (where l represents a halogen atom and l represents a number 1 ≤ l ≤ 2) and an organic aluminum compound.

[0016] The seventh invention of the present invention is characterized in that, in the first to sixth inventions, the polyolefin resin molding material is used to mold PET bottle caps for non-carbonated beverages.

[0017] The 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 PET bottle caps for non-carbonated beverages.

[0018] The ninth invention of the present invention is a PET bottle cap for non-carbonated beverages made by molding a polyolefin-based resin molding material according to the first to sixth inventions. [Effects of the Invention]

[0019] According to the present invention, by modifying a polyolefin-based recycled resin obtained by homogenizing used PET bottle caps with a polyethylene-based resin that has excellent rigidity and durability (stress crack resistance), the durability (stress crack resistance) of the polyolefin-based recycled resin can be improved to the level required for typical non-carbonated beverage PET bottle cap products without significantly changing the physical properties required for PET bottle caps, and especially without compromising rigidity. Therefore, it is possible to create a polyolefin-based resin molding material with a better balance of physical properties than polyolefin-based recycled resin made by simply homogenizing PET bottle caps collected from the market, and particularly preferably, it becomes possible to realize material recycling from PET bottle caps collected from the market to new PET bottle caps. [Brief explanation of the drawing]

[0020] [Figure 1]Figure 1 is a graph showing equation (b) which illustrates the preferred relationship between CSDA (comonomer sequence distribution) and SCBA (number of short-chain branches 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. [Modes for carrying out the invention]

[0021] The characteristics of the polyolefin-based resin molding material of the present invention will be described in detail below. In this invention, the "~" indicating a numerical range is used to mean that the values ​​written before and after it are included as the lower and upper limits. The polyolefin-based resin molding material of the present invention is a resin composition comprising a polyolefin-based recovered resin obtained by homogenizing market-recovered polyolefin-based resin caps of PET bottles, and a modifier made of the following polyethylene-based resin, wherein the content of the modifier is 1 to 99% by mass of the total amount of the polyolefin-based recovered resin and the modifier. [Modifier made from polyethylene resin] A modifying material made of polyethylene resin that contains 20% to 40% by mass of component (A) and 60% to 80% by mass of component (B) as an ethylene polymer, and satisfies the following characteristics (1) to (4). Components (A): HLMFR 0.05-5.0 g / 10 min, density 0.910-0.935 g / cm³ 3 and 13 The value of CSD (comonomer sequence distribution) obtained from the measured C-NMR spectrum using formula (a) (CSD A ) ethylene polymers with a ratio of 0.0 to 3.0 CSD = 4 × [EE][CC] / [EC] 2 Formula (a) (In formula (a), [EE] represents the ethylene-ethylene chain number, [CC] represents the comonomer-comonomer chain number, and [EC] represents the ethylene-comonomer chain number.) Components (B): MFR of 100g / 10 min or more and less than 600g / 10 min, density of 0.960g / cm³ 3More than 0.980g / cm 3 Ethylene polymers less than Characteristics (1): The melt flow rate (MFR) at a temperature of 190°C and a load of 2.16 kg is between 0.2 g / 10 min and 3.0 g / 10 min, and the high-load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is between 70 g / 10 min and 180 g / 10 min, and the HLMFR / MFR ratio is between 50 and 500. Property (2): Density is 0.955 g / cm³ 3 More than 0.970g / cm 3 The following is Characteristic (3): The full notch creep test (FNCT) at 80°C and 1.9 MPa is 100 hours or more. Characteristic (4): Charpy impact strength of 9.0 kJ / m 2 That's all.

[0022] 1. Recall of PET bottle caps made of polyolefin resin. In this invention, the market-recovered polyolefin resin caps for PET bottles refer to polyolefin resin caps that have been separated and recovered from used PET bottles. Resin caps for PET bottles are molded articles made from polyolefin resins such as polyethylene and polypropylene worldwide, with polyethylene caps being particularly widely used. Polyolefin resin caps can be separated and recovered by known methods; for example, polyolefin resin caps can be separated based on the difference in specific gravity of the resins forming the caps, and if necessary, polyethylene resin caps can be separated further. Among the polyolefin resin caps for PET bottles, it is preferable to use market-recovered products that have been separated specifically from polyethylene caps, from the viewpoint of improving the quality of the polyolefin resin molding material obtained in this invention. In the present invention, the polyolefin-based recycled resin obtained by homogenizing market-recovered polyolefin-based resin caps is a polyolefin-based resin composition in which the resin composition and properties are homogenized by returning market-recovered products, which consist of various polyolefin-based resin caps with different individual qualities, back to the state of the raw resin material through material recycling methods such as crushing and pelletizing. Recycled resin, which is made by crushing and uniformly mixing separated PET bottle caps and processing them into pellets, is commercially available. In this invention, such commercially available products may be used as the market-recovered polyolefin resin caps.

[0023] The physical properties of PET bottle caps collected from the market vary greatly depending on the proportions of cap products of different qualities that are mixed together, so it is not possible to state their physical properties in general. To give an extreme example, if a market collection consists almost entirely of PET bottle caps for non-carbonated beverages, the performance of the polyolefin-based recovered resin obtained from that market collection will be close to that of PET bottle caps for non-carbonated beverages. Conversely, if a market collection consists almost entirely of PET bottle caps for carbonated beverages, the performance of the polyolefin-based recovered resin obtained from that market collection will be close to that of PET bottle caps for carbonated beverages. Furthermore, if low-quality PET bottle caps, such as inexpensive imported products, are included in the market-recovered products, the performance of the polyolefin-based recycled resin obtained from these market-recovered products will be negatively affected and reduced. Since a certain amount of low-quality PET bottle caps are generally included in market-recovered products, the performance of the polyolefin-based recycled resin obtained from PET bottle caps recovered from the market is not only insufficient for carbonated beverages, but is also at a level where it cannot even be used for PET bottles for non-carbonated beverages. In particular, the durability (stress crack resistance) is often too low for use as PET bottles for non-carbonated beverages.

[0024] In the present invention, a polyolefin-based recovered resin having a flexural modulus of 900 to 1000 MPa, which indicates rigidity, and an environmental stress crack resistance (ESCR) of 15 to 35 hours (h), which indicates durability (stress crack resistance), is preferably used as the modified polyolefin-based recovered resin. If the flexural modulus of the polyolefin-based recovered resin is less than 850 MPa, or if the environmental stress crack resistance (ESCR) of the polyolefin-based recovered resin is less than 10 hours, a large amount of modifying material is required to improve its durability (stress crack resistance) to a level suitable for use as a PET bottle cap product for non-carbonated beverages without impairing the rigidity of the polyolefin-based recovered resin, often resulting in low modification efficiency. Furthermore, if the flexural modulus of the polyolefin-based recovered resin exceeds 1050 MPa and the environmental stress crack resistance (ESCR) of the polyolefin-based recovered resin exceeds 45 hours, it maintains a performance level suitable for use as a PET bottle cap product for non-carbonated beverages, and therefore, there is often little need to modify it to improve its performance.

[0025] 2. Modifier made of polyethylene resin In the present invention, by adding a polyethylene-based resin molding material suitable for PET bottle caps for carbonated beverages, as described in Patent Document 1, as a modifier for the polyolefin-based recovered resin, the durability (stress crack resistance) of the polyolefin-based recovered resin can be improved to a level suitable for use as a PET bottle cap product for non-carbonated beverages, without impairing the rigidity of the polyolefin-based recovered resin during modification. In the present invention, the modified material may be the virgin resin used as the raw material for molding PET bottle caps for carbonated beverages, or it may be recycled and pelletized from scraps of resin molding material or in-process recovered materials generated during the molding of PET bottle caps for carbonated beverages.

[0026] Specifically, the modifier used in the present invention is a polyethylene resin containing 20% ​​to 40% by mass of component (A) and 60% to 80% by mass of component (B) as an ethylene polymer, and satisfying the following characteristics (1) to (4). Components (A): HLMFR 0.05-5.0 g / 10 min, density 0.910-0.935 g / cm³ 3 and 13 The value of CSD (comonomer sequence distribution) obtained from the measured C-NMR spectrum using formula (a) (CSD A ) ethylene polymers with a ratio of 0.0 to 3.0 CSD = 4 × [EE][CC] / [EC] 2 Formula (a) (In formula (a), [EE] represents the ethylene-ethylene chain number, [CC] represents the comonomer-comonomer chain number, and [EC] represents the ethylene-comonomer chain number.) Components (B): MFR of 100g / 10 min or more and less than 600g / 10 min, density of 0.960g / cm³ 3 More than 0.980g / cm 3 Ethylene polymers less than Characteristics (1): The melt flow rate (MFR) at a temperature of 190°C and a load of 2.16 kg is between 0.2 g / 10 min and 3.0 g / 10 min, and the high-load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is between 70 g / 10 min and 180 g / 10 min, and the HLMFR / MFR ratio is between 50 and 500. Property (2): Density is 0.955 g / cm³ 3 More than 0.970g / cm 3 The following is Characteristic (3): The full notch creep test (FNCT) at 80°C and 1.9 MPa is 100 hours or more. Characteristic (4): Charpy impact strength of 9.0 kJ / m 2 That's all.

[0027] The modifier used in this invention has a performance level suitable for 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 polyethylene resins that do not satisfy the above characteristics (1) to (4) are used as modifiers for polyolefin-based recovered resins, a sufficient modification effect cannot be obtained, and the performance of the resulting polyolefin-based resin molding material will also decrease.

[0028] (1) Requirements for the material of the modifier Characteristics (1) The modified material, which is made of polyethylene resin, has a melt flow rate (MFR) of 0.2 g / 10 min to 3.0 g / 10 min at a temperature of 190°C and a load of 2.16 kg, preferably 0.3 to 2.8 g / 10 min, and more preferably 0.5 to 2.5 g / 10 min. If the MFR is less than 0.2 g / 10 min, the fluidity is insufficient, and the high-speed moldability of the modified material of the present invention cannot be expected. If it exceeds 3.0 g / 10 min, the stress crack resistance and impact resistance of the modified material of the present invention are not necessarily sufficient. Furthermore, the modified material made of polyethylene resin has a high-load melt flow rate (HLMFR) of 70 g / 10 min or more and less than 180 g / 10 min at a temperature of 190°C and a load of 21.6 kg, preferably 80 to 170 g / 10 min, and more preferably 90 to 160 g / 10 min. If the HLMFR is less than 70 g / 10 min, the fluidity is insufficient, and the high-speed moldability of the modified material of the present invention cannot be expected. If it is 180 g / 10 min or more, the stress crack resistance and impact resistance of the modified material of the present invention are not necessarily sufficient. Furthermore, the ratio of the melt flow rate (MFR) to the high-load melt flow rate (HLMFR), i.e., HLMFR / MFR, is 50 to 500, preferably 60 to 400, more preferably 70 to 300, and even more preferably 160 to 200. If HLMFR / MFR is less than 50, there is no viscosity reduction at a given shear rate, resulting in insufficient fluidity and reduced high-speed moldability of the modifier of the present invention. If it exceeds 500, shrinkage anisotropy of the modifier of the present invention is likely to occur. In this invention, MFR and HLMFR are values ​​measured in accordance with JIS-K6922-2:1997.

[0029] Characteristics (2) The modifier, made of polyethylene resin, has a density of 0.955 g / cm³. 3 More than 0.970g / cm 3 The following, preferably 0.956 to 0.968 g / cm³ 3 More preferably 0.958~0.965 g / cm³ 3 Its density is 0.955 g / cm³. 3 Below this density, the rigidity of the modified material of the present invention decreases, making it impossible to thin the container lid, and it becomes prone to deformation at high temperatures. This can cause the container lid to deform due to the influence of internal container pressure, leading to leakage. 3 If the value exceeds a certain point, the stress crack resistance of the modified material of the present invention may not be sufficient. In this invention, the density of the polyethylene resin molding material is a value measured in accordance with JIS-K6922-1,2:1997.

[0030] Characteristics (3) The modified material, made of polyethylene resin, has a full-notch creep test (FNCT) at 80°C and 1.9 MPa, with a fracture time (FNCT) of 100 hours or more, more preferably 110 hours or more, and even 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 molded using the modified material of the present invention will break due to stress cracks when stored at high temperatures in the summer. Here, FNCT is measured in accordance with JIS-K6774:1998, at a temperature of 80°C, using a 1% aqueous solution of Emal manufactured by Kao Corporation as the working solution.

[0031] Characteristics (4) The modified material, made of polyethylene resin, has a Charpy impact strength of 9.0 kJ / m². 2 The above is the standard, preferably 10-20 kJ / m³. 2 And more preferably 14-20 kJ / m 2The Charpy impact strength is 9.0 kJ / m². 2 Below a certain level, if the container is dropped after being filled with liquid, the container lid molded using the modified material of the present invention is prone to cracking. The Charpy impact strength is measured in accordance with JIS-K7111-1:2006.

[0032] Characteristics (5) The modifier, made of polyethylene resin, preferably has a flexural modulus of 900 to 1500 MPa, and more preferably 950 to 1450 MPa. If the flexural modulus is less than 900 MPa, the rigidity decreases, and the container lid molded using the modifier of the present invention becomes easily deformed by 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 × 10 × 80 mm plate-like body injection-molded at 210°C as a test specimen.

[0033] Characteristics(6) The modified material, made of polyethylene resin, withstands temperatures of 190°C and a shear rate of 400 sec. -1 The viscosity at the time of melting is preferably 200 to 1000 Pa·s, more preferably 250 to 600 Pa·s, and even more preferably 420 to 600 Pa·s. If the melt viscosity is less than 200 Pa·s, the modifier of the present invention exhibits excellent high fluidity, but the stress crack resistance and impact resistance of the container lid molded using the modifier are reduced, making it impossible to achieve both fluidity and stress crack resistance / impact resistance. If the melt viscosity exceeds 1000 Pa·s, the fluidity decreases, resulting in reduced high-speed moldability.

[0034] Characteristics (7) The modified material, which is made of polyethylene resin, preferably has a tensile yield strength of 25 MPa or more, more preferably 26 MPa or more, and more preferably 27 MPa or more. If the tensile yield strength is less than 25 MPa, the bridge portion of the container lid molded using the modified material of the present invention will not cut cleanly and will lack adequate 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. Tensile yield strength correlates with the loosening of the container lid; a low tensile yield strength makes the container lid more prone to loosening, resulting in insufficient sealing with adequate stiffness. Improving the stress crack resistance and impact resistance of the container lid requires reducing the density of the polyethylene material, making it difficult to improve tensile yield strength while simultaneously improving stress crack resistance and impact resistance. However, according to the present invention, it is possible to improve the looseness, stress crack resistance, and impact resistance of the container lid across the board.

[0035] Characteristics (8) The modifying material made of polyethylene resin preferably has a hydrocarbon volatile content of 80 ppm or less. Preferably, the hydrocarbon volatile content is 50 ppm or less, and more preferably 30 ppm or less. In this invention, hydrocarbons refer to compounds that contain at least carbon and hydrogen in their molecules, and are usually measured by gas chromatography. By keeping the hydrocarbon content below a predetermined value, it is possible to prevent the influence of odor and flavor on the contents of the container. Here, the amount of hydrocarbon volatile content is obtained by measuring the air in the head space by gas chromatography when 1 g of the modifying material made of polyethylene resin is placed in a 25 ml glass sealed container and heated at 130 °C for 60 minutes.

[0036] (2) Composition of the modifier The polyethylene resin modifier is a composition of multiple types of ethylene polymers, containing 20% ​​to 40% by mass of component (A) and 60% to 80% by mass of component (B). The polyethylene resin modifier may be composed of a single ethylene polymer or as a composition of multiple types of ethylene polymers. Components (A): HLMFR 0.05-5.0 g / 10 min, density 0.910-0.935 g / cm³ 3 ,and 13 The value of CSD (comonomer sequence distribution) obtained from the measured C-NMR spectrum using formula (a) (CSD A ) ethylene polymers with a ratio of 0.0 to 3.0 CSD = 4 × [EE][CC] / [EC] 2 Formula (a) (In formula (a), [EE] represents the ethylene-ethylene chain number, [CC] represents the comonomer-comonomer chain number, and [EC] represents the ethylene-comonomer chain number.) Component (B): Melt flow rate (MFR) at 190°C and 2.16 kg load is 100 g / 10 min or more and less than 600 g / 10 min, density is 0.960 g / cm³ 3 More than 0.980g / cm 3 Ethylene polymers less than

[0037] Furthermore, MFR, HLMFR, and density are measured by the measurement method described above. Furthermore, the CSD (comonomer sequence distribution) of component (A) of the ethylene polymer is based on the description in JCRandall, JMS-REV.MACROMOL.CHEM.PHYS., C29(2&3), pp. 201-317 (1989), for the ethylene polymer. 13 It is measured by 13C-NMR spectroscopy. Specifically, it is measured using a JEOL-GSX400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. under the following conditions, and the ethylene-ethylene chain number, comonomer-comonomer chain number, and ethylene-comonomer chain number can be determined from the values ​​using the above formula (a). Instrument: JEOL-GSX400 manufactured by JEOL Ltd., pulse width: 8.0 μsec (flip angle = 40°), pulse repetition time: 5 seconds, number of integrations: 5000 or more, solvent and internal standard: 1,2,4-trichlorobenzene / benzene-d6 / hexamethyldisiloxane (mixing ratio: 30 / 10 / 1), measurement temperature: 120°C, sample concentration: 0.3 g / ml. Subsequently, the spectrum obtained from the measurement can be determined based on the following literature. (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)

[0038] Generally, the CSD of ethylene polymers ranges from 0 to infinity. A high CSD value indicates that comonomers are inserted more blockily, while a low CSD value indicates that comonomers are inserted more alternately (or randomly). A smaller CSD value indicates a better compositional distribution.

[0039] (2-1) Ethylene polymer of component (A) The ethylene polymer of component (A) has an HLMFR of 0.05 to 5.0 g / 10 min, preferably 0.1 to 3.0 g / 10 min, and more preferably 0.3 to 2.0 g / 10 min. If the HLMFR of component (A) is less than 0.05 g / 10 min, the fluidity of the modifier of the present invention tends to decrease, resulting in poor moldability. If it exceeds 5.0 g / 10 min, the stress crack resistance and impact resistance of the modifier of the present invention tend to decrease.

[0040] The density of component (A) is 0.910 to 0.935 g / cm³. 3 The concentration is preferably 0.915 to 0.935 g / cm³. 3 More preferably 0.918~0.932 g / cm³ 3 More preferably 0.920~0.930 g / cm³ 3 The density of component (A) is 0.910 g / cm³. 3 Below 0.935 g / cm³, the rigidity of the modified material of the present invention becomes insufficient. 3 Beyond a certain point, the stress crack resistance and impact resistance of the modified material of the present invention tend to decrease.

[0041] Component (A) of the ethylene polymer is 13 The value of CSD (comonomer sequence distribution) was measured by 13C-NMR spectroscopy and determined by formula (a). A However, it is between 0.0 and 3.0, preferably between 0.0 and 2.5, and more preferably between 0.0 and 2.2. CSD of component (A) A When the value falls within the range of the present invention, i.e., 0.0 to 3.0, the modified material of the present invention exhibits an excellent balance of rigidity, stress crack resistance, and impact resistance. On the other hand, CSD A If the value is greater than 3.0, it indicates a broad compositional distribution, and the balance between the rigidity, stress crack resistance, and impact resistance of the modified material of the present invention tends to decrease. On the other hand, the CSD of component (A) A A value greater than 3.0 indicates a broad compositional distribution, resulting in a reduced balance between the rigidity, stress crack resistance, and impact resistance of the modifier of the present invention. CSD is influenced by both intermolecular and intramolecular compositional distributions. In Ziegler-Natta catalysts, the intermolecular compositional distribution is dominant, and a smaller CSD value suggests less variation in the amount of comonomer copolymerization between molecules and a narrower compositional distribution. In the present invention, the CSD of component (A) A The smaller the value, the better, because the way the short chain branches are inserted becomes more uniform, and the molecular weight is 10 5 This is because, among the above components or component (A), the number of components that do not satisfy the desired density (number of short-chain branches) is reduced, making it easier to achieve the effect of improving the balance between the rigidity, stress crack resistance, and impact resistance of the modified material of the present invention.

[0042] The ethylene polymer of component (A) may be a polymer of ethylene alone, but a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is preferred, and a copolymer of ethylene and 1-butene, or a copolymer of ethylene and 1-hexene, is even more preferred. The copolymerization ratio of the α-olefin having 3 to 20 carbon atoms is preferably 0.001 to 5.0 mol%.

[0043] (2-2) Ethylene polymer of component (B) The ethylene polymer of component (B) has an MFR of 100 g / 10 min or more and less than 600 g / 10 min, preferably 180 to 500 g / 10 min, and more preferably 200 to 350 g / 10 min. If the MFR of component (B) is less than 100 g / 10 min, the fluidity of the modifier of the present invention tends to decrease and moldability tends to be poor, and if it is 600 g / 10 min or more, the stress crack resistance and impact resistance of the modifier of the present invention tend to decrease. The density of component (B) is 0.960 g / cm³. 3 More than 0.980g / cm 3 Less than 0.965-0.975 g / cm³ 3 More preferably 0.965~0.970 g / cm³ 3 The density of component (B) is 0.960 g / cm³. 3 If the value is less than 0.980 g / cm³, the rigidity of the modifying material of the present invention may decrease. 3 The above items are difficult to manufacture. The ethylene-based 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, a copolymer of ethylene and 1-butene, or a copolymer of ethylene and 1-hexene. 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%.

[0044] In the present invention, the ratio of component (A) to component (B) is 20% by mass or more and 40% by mass or less for component (A), and 60% by mass or more and 80% by mass or less for component (B), preferably 20-35% by mass for component (A) and 65-80% by mass for component (B), and more preferably 20-30% by mass for component (A) and 70-80% by mass for component (B). If the content (A) is less than 20% by mass, the stress crack resistance and impact resistance of the modifier of the present invention will decrease. If it exceeds 40% by mass, the moldability of the modifier of the present invention tends to decrease. If the content (B) is less than 60% by mass, the moldability of the modifier of the present invention will decrease. If it exceeds 80% by mass, the stress crack resistance and impact resistance of the modifier of the present invention tend to decrease. If it is out of this range, one or more of fluidity, rigidity, stress crack resistance, and impact resistance may be insufficient, and the performance balance may deteriorate. In the present invention, the ethylene-based polymer may be composed of only the component (A) and the component (B), or may contain other optional resin components and the like.

[0045] (3) Other requirements as a composition of the modifier [Relationship between CSD and SCB of component (A)] In the present invention, the ethylene-based polymer of the component (A) 13 The value of CSD (comonomer sequence distribution) (CSD A ) obtained by the formula (a) from the measurement value by the C-NMR spectrum, and 13 The number of short-chain branches SCB of carbon atoms 1 to 20 per 1,000 carbon atoms in the main chain measured by the C-NMR spectrum A (per 1,000C) preferably satisfy the following formula (b). More preferably, in the present invention, CSD A and SCB A satisfy the following formula (c). Even more preferably, it satisfies the following formula (d). 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)

[0046] In the ethylene-based polymer, the CSD value is affected by the number of short-chain branches. The fewer the number of short-chain branches, the relatively more ethylene-ethylene chains, and the higher the ratio of [EE] to [CC] and [EC] in formula (a), resulting in a higher CSD value. Therefore, even with the same CSD value, it can be said that the composition distribution is better for those with fewer short-chain branches.

[0047] Here, CSD A and SCB A are within the scope of the present invention, that is, when satisfying formula (b), it is in the lower region below the line in FIG. 1, but the balance of the rigidity, stress crack resistance, and impact resistance of the modifier of the present invention is excellent. On the other hand, when not satisfying formula (b), it is in the upper region above the line in FIG. 1, indicating a wide composition distribution, and the balance of the rigidity, ESCR, and impact resistance of the modifier of the present invention tends to decrease. CSD in the present invention A and SCB A The relational expression between them is obtained by approximating the CSD A as a function of SCB A to set the preferable range of the polyethylene-based resin as the modifier. In the present invention, even if the modifier made of the polyethylene-based resin satisfies the relational expression, if other properties are not satisfied, the desired property balance as the modifier cannot be obtained.

[0048] In the present invention, in order to obtain a modifier made of a polyethylene-based resin that satisfies the relational expression between CSD A and SCB A it is important to control the insertion of the comonomer, and various methods can be mentioned. For example, the polymerization conditions and the catalyst system for polymerization are one of the important factors. It can be easily controlled by using a catalyst composed of a combination of a solid catalyst obtained from a specific magnesium compound, titanium compound, and organoaluminum halide compound described in 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 an organoaluminum compound.

[0049] [Anisotropic shrinkage (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. Preferably, the MD / TD is 1.0 or more and less than 2.3, and more preferably 1.1 or more and 2.2 or less. This value is obtained by performing flat plate molding of 120 × 120 × 2 mm with a film gate on one side (gate thickness 0.2 mm) at a molding temperature of 190°C and a mold temperature of 40°C, measuring the shrinkage rate in the flow direction (MD) and perpendicular to the flow direction (TD) after molding and leaving it at 23°C for 48 hours, and dividing the MD value by the TD value. If the shrinkage anisotropy (MD / TD) is 2.5 or more, the molded product is prone to cracking, while if it is less than 1.0, the product is prone to deformation. The shrinkage anisotropy (MD / TD) can be adjusted by the molecular weight distribution.

[0050] 3. Manufacturing of modifiers made from polyethylene resins The ethylene polymers contained in the polyethylene resin modifier can be produced by the homopolymerization of ethylene alone, or by the copolymerization of ethylene and α-olefin. While the ethylene polymers in the polyethylene resin modifier can be obtained by conventional single-step polymerization, they can also be produced as compositions by mixing components polymerized under different conditions or by sequential multi-step polymerization.

[0051] (1) Preparation of compositions by mixing or stepwise multi-stage polymerization A modifying agent made of polyethylene resin can be obtained by mixing the ethylene polymer of component (A) and the ethylene polymer of component (B). For reasons such as the uniformity of the resin, it is preferable to obtain a product obtained by sequentially and continuously polymerizing the ethylene polymer of component (A) and the ethylene polymer of component (B) (sequential multi-stage polymerization method). For example, it can be obtained by sequentially and continuously polymerizing ethylene and α-olefin in multiple reactors connected in series. In this case, the ethylene homopolymer can be polymerized in one polymerization reactor and the copolymer of ethylene and an α-olefin with 3 to 20 carbon atoms can be polymerized in the other polymerization reactor, or the copolymer of ethylene and an α-olefin with 3 to 20 carbon atoms can be polymerized in one polymerization reactor and the copolymer of ethylene and an α-olefin with 3 to 20 carbon atoms can be further copolymerized in the other polymerization reactor, but the former is preferred. In other words, in the present invention, it is preferable that at least one of component (A) and component (B) of the ethylene polymer is polymerized in a multi-stage polymerization using at least two polymerization reactors in the presence of a polymerization catalyst, wherein an ethylene homopolymer is polymerized in at least one of the two 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.

[0052] Furthermore, the composition consisting of component (A) and component (B) may be obtained by polymerizing component (A) and component (B) separately and then mixing them. Moreover, each of the ethylene polymers of component (A) and component (B) can be composed of multiple components. The ethylene polymer may be a polymer polymerized sequentially and continuously in a multi-stage polymerization reactor using one type of catalyst, a polymer produced in a single-stage or multi-stage polymerization reactor using multiple types of catalysts, or a mixture of polymers polymerized using one or more types of catalysts.

[0053] (2) Polymerization method The ethylene polymer of component (A) and the ethylene polymer of component (B) can be produced by manufacturing processes such as gas-phase polymerization, solution polymerization, and slurry polymerization, with slurry polymerization being preferred. The polymerization temperature for the ethylene polymer can be selected from a 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. The polymerization pressure is atmospheric pressure to approximately 100 kg / cm². 2It can be selected from the range. It can preferably be produced by slurry polymerization of ethylene and α-olefins in the presence of an inert hydrocarbon solvent 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, while substantially free from oxygen and moisture.

[0054] In slurry polymerization, the hydrogen supplied to the polymerizer is consumed as a chain transfer agent, determining the average molecular weight of the resulting ethylene polymer, and some of it dissolves in the solvent and is discharged from the polymerizer. The solubility of hydrogen in the solvent is low, and unless a large amount of gas is present in the polymerizer, the hydrogen concentration near the polymerization active sites of the catalyst is low. Therefore, by changing the hydrogen supply rate, the hydrogen concentration at the polymerization active sites of the catalyst changes rapidly, and the molecular weight of the resulting ethylene polymer changes in a short time in accordance with the hydrogen supply rate. Consequently, by changing the hydrogen supply rate in short cycles, a more homogeneous product can be produced, making slurry polymerization a preferable polymerization method. Furthermore, while the hydrogen supply rate can be changed continuously, discontinuous changes are more effective in broadening the molecular weight distribution. In the present invention, it is important to change the amount of hydrogen supplied during the polymerization of ethylene-based polymers, but it is also important to appropriately change other polymerization conditions, such as polymerization temperature, catalyst supply amount, olefin supply amount such as ethylene, comonomer supply amount such as 1-butene, and solvent supply amount, either simultaneously with or separately from the change in hydrogen.

[0055] (3) Sequential multistage polymerization The so-called sequential multi-stage polymerization method, in which polymerization is carried out sequentially in multiple reactors connected in series, may be a method in which a high molecular weight component is produced in the first polymerization region (first-stage reactor), the resulting polymer is transferred to the next reaction region (second-stage reactor), and a low molecular weight component is produced in the second-stage reactor, or a method in which a low molecular weight component is produced in the first polymerization region (first-stage reactor), the resulting polymer is transferred to the next reaction region (second-stage reactor), and a high molecular weight component is produced in the second-stage reactor. A specific preferred polymerization method is as follows: Using a Ziegler catalyst containing a titanium-based transition metal compound and an organoaluminum compound, and at least two reactors, ethylene and α-olefins are introduced into the first reactor to produce a low-density polymer with high molecular weight components, the polymer withdrawn from the first reactor is transferred to the second reactor, and ethylene and hydrogen are introduced into the second reactor to produce a high-density polymer with low molecular weight components. In the case of multi-stage polymerization, the amount and properties of the ethylene-based polymer produced in the polymerization region from the second stage onward can be determined by calculating the amount of polymer produced in each stage (which can be determined by analyzing unreacted gases), measuring the physical properties of the polymer extracted after each stage, and then determining the physical properties of the polymer produced in each stage based on its additivity.

[0056] (4) Polymerization catalyst Various catalysts are used as polymerization catalysts for ethylene polymers, including Ziegler catalysts, Philips catalysts, and metallocene catalysts. Any polymerization catalyst that exhibits hydrogen chain transfer activity in olefin polymerization can be used. Specifically, any catalyst suitable for slurry-type olefin polymerization, consisting of a solid catalyst component and an organometallic compound, that exhibits hydrogen chain transfer activity in olefin polymerization, can be used. Preferably, it is a heterogeneous catalyst with localized polymerization active sites. The solid catalyst component is not particularly limited as long as it is a solid catalyst used for olefin polymerization that contains a transition metal compound.

[0057] As transition metal compounds, compounds of metals from Group IV to VIII of the periodic table, preferably Group IV to VI, can be used. Specific examples include compounds of Ti, Zr, Hf, V, Cr, and Mo. A preferred example of a catalyst is a solid Ziegler catalyst consisting of a Ti and / or V compound and an organometallic compound of a Group I to III metal from the periodic table. Furthermore, examples include metallocene catalysts, which are complexes formed by co-catalysts with ligands having a cyclopentadiene skeleton coordinated to a transition metal. Specific metallocene catalysts include complex catalysts formed by co-catalysts with ligands having a cyclopentadiene skeleton, such as methylcyclopentadiene, dimethylcyclopentadiene, and indene, to transition metals including Ti, Zr, Hf, and the lanthanide series, and organometallic compounds of Group I to III metals from the periodic table, such as aluminoxanes, as co-catalysts, or supported types in which these complex catalysts are supported on a carrier such as silica. Particularly preferred solid catalyst components for olefin polymerization include those containing at least titanium and / or vanadium and magnesium. As organometallic compounds that can be used with the above-mentioned solid catalyst component containing at least titanium and / or vanadium and magnesium, organoaluminum compounds, particularly trialkylaluminum, are preferred. The amount of organoaluminum compound used in the polymerization reaction is not particularly limited, but is usually in the range of 0.05 to 1,000 moles per mole of titanium compound. More specifically, a Ziegler catalyst consisting of a solid catalyst component and an organoaluminum compound is preferred, and this can be suitably carried out by using the catalyst and manufacturing method described in the following prior art documents. Specifically, it is preferable to polymerize olefins using the catalyst system described in Japanese Patent Publication No. 56-61406, Japanese Patent Publication No. 56-141304, Japanese Patent Publication No. 56-166206, Japanese Patent Publication No. 57-141407, Japanese Patent Publication No. 60-235813, and Japanese Patent Publication No. 61-246209. In the present invention, the polymerization catalyst for ethylene-based polymers is a polymer of the general formula Mg(OR 2 ) m X 2 2-m(In the formula, R 2 X represents alkyl, aryl, or cycloalkyl groups. 2 Compounds represented by the general formula Ti(OR) (where m is 1 or 2, where m represents a halogen atom) and 3 ) n X 3 4-n (In the formula, R 3 X represents alkyl, aryl, or cycloalkyl groups. 3 A homogeneous hydrocarbon solution containing a compound represented by the general formula AlR (where is a halogen atom and n is 1, 2, or 3), 1 l X 1 3-l (In the formula, R 1 X represents alkyl, aryl, or cycloalkyl groups. 1 A catalyst system comprising a hydrocarbon-insoluble solid catalyst obtained by treatment with an organoaluminum halide compound (where l represents a halogen atom and l represents a number 1 ≤ l ≤ 2) and an organoaluminum compound is preferred.

[0058] (5) Polymerized monomers In the present invention, ethylene polymers are obtained by the homopolymerization of ethylene, or by copolymerization of ethylene with α-olefins having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc. In the case of copolymerization, 1-butene and 1-hexene are listed as preferred monomers. Furthermore, copolymerization with dienes is possible for the purpose of modification. Examples of diene compounds that can be used in this case include butadiene, 1,4-hexadiene, ethylidene norbornene, and dicyclopentadiene. The comonomer content during polymerization can be arbitrarily selected, but for example, in the copolymerization of ethylene with α-olefins having 3 to 12 carbon atoms, the α-olefin content in the ethylene-α-olefin copolymer is preferably 0.001 to 5.0 mol%. As the raw material ethylene, plant-derived ethylene can be used for polymerization, and an ethylene-based polymer using such ethylene is also acceptable.

[0059] 4. Method for controlling characteristic values ​​in modifiers made of polyethylene resin (1) MFR and HLMFR In the production of modifiers made from polyethylene resins, the MFR and HLMFR can be adjusted to a desired range by controlling the polymerization temperature of the ethylene monomer and the use of chain transfer agents. Specifically, increasing the polymerization temperature of ethylene and α-olefins lowers the molecular weight, resulting in larger MFRs and HLMFRs, while decreasing the polymerization temperature increases the molecular weight, resulting in smaller MFRs and HLMFRs. Furthermore, in the copolymerization reaction between ethylene and α-olefins, increasing the amount of coexisting hydrogen (amount of chain transfer agent) lowers the molecular weight, resulting in larger MFRs and HLMFRs, while decreasing the amount of coexisting hydrogen (amount of chain transfer agent) increases the molecular weight, resulting in smaller MFRs and HLMFRs.

[0060] (2) HLMFR / MFR In the production of modifiers made from polyethylene resins, the HLMFR / MFR (flow ratio FLR) can be increased or decreased by adjusting the molecular weight distribution. This HLMFR / MFR correlates with the monodispersity of molecular weight (mass-average molecular weight Mw / number-average molecular weight Mn) determined by gel permeation chromatography, and an HLMFR / MFR of 100 corresponds to approximately 18 in monodispersity Mw / Mn. The HLMFR / MFR or Mw / Mn can be adjusted by the type of catalyst, the type of co-catalyst, polymerization temperature, residence time in the polymerization reactor, the number of polymerization reactors, etc., and can also be adjusted by the temperature, pressure, shear rate of the extruder, etc. Preferably, it 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 molecular weight distribution of ethylene polymers is easily affected by the type of catalyst. Generally, a broad molecular weight distribution is obtained with a Philipps catalyst, a narrow molecular weight distribution with a metallocene catalyst, and an intermediate molecular weight distribution with a Ziegler catalyst.

[0061] (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.

[0062] (4) CSD In a modifier made of polyethylene resin, a high CSD value of component (A) indicates that comonomers are inserted more block-wise, while a low CSD value indicates that comonomers are inserted more alternately (or randomly). While there are various methods for controlling comonomer insertion, with continuous technological innovation in the field of polyolefin polymerization, the polymerization catalyst system is one of the important elements for the polyethylene resin modifier used in the present invention. This can be easily controlled by using a catalyst that combines a solid catalyst obtained from specific magnesium compounds, titanium compounds, or organic aluminum halide compounds described in the previously mentioned known patent documents (Japanese Patent Publication No. 56-61406, Japanese Patent Publication No. 56-141304, Japanese Patent Publication No. 56-166206, Japanese Patent Publication No. 57-141407, Japanese Patent Publication No. 60-235813, Japanese Patent Publication No. 61-246209) with an organic aluminum compound.

[0063] (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 modifiers made from polyethylene resins, 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 correlates with density; for example, at a density of 0.916 g / cm³ 3 Approximately 14 particles per 1,000°C, with a density of 0.930 g / cm³. 3 This results in approximately 4 pieces per 1,000C.

[0064] (6) Control of other characteristic values In the production of modifiers made from polyethylene resins, increasing the full notch creep time (FNCT) at 80°C and 1.9 MPa, as measured by the full notch creep test, can be achieved by adding low-density, high-molecular-weight components. ESCR can be achieved by adjusting the density, molecular weight, and molecular weight distribution, and by appropriately using low-density and high-molecular-weight components of component (A) in the present invention. Charpy impact strength can be increased by lowering the high-load melt flow rate (HLMFR) or reducing the density.

[0065] The flexural modulus can be adjusted by increasing or decreasing the molecular weight and density of polyethylene; increasing the molecular weight or density can increase the flexural modulus. 190℃, shear rate 400sec -1 The viscosity at melt can be adjusted by increasing or decreasing the molecular weight and density of polyethylene; increasing the molecular weight increases the viscosity at melt. The tensile yield strength can be adjusted by increasing or decreasing the density; increasing the density increases the yield strength. To reduce hydrocarbon volatile content to below a predetermined level, this can be achieved by performing volatile content removal operations on the polymerized polyethylene polymer, such as steam stripping, hot air deodorization, vacuum treatment, or nitrogen purging. Steam deodorization, in particular, is highly effective in controlling this content. While the conditions for steam treatment are not particularly limited, it is preferable to expose the ethylene polymer to 100°C steam for about 8 hours.

[0066] 5. Amount of modifying material made of polyethylene resin In this invention, the content of the modifier is appropriately adjusted within the range of 1 to 99% by mass relative to the total amount of the polyolefin-based recovered resin and the modifier. In order to improve the durability (stress crack resistance) of polyolefin-based recovered resin recycled from PET bottle caps collected from the market to the level of PET bottle cap products for non-carbonated beverages, it is necessary to add an appropriate amount of modifier according to the performance of the polyolefin-based recovered resin. If the performance of the polyolefin-based recovered resin is high, a small amount of modifier is sufficient, but if its performance is low, a large amount of modifier will be required. From the viewpoint of improving the durability (stress crack resistance) of the polyolefin-based recycled resin, which is recycled from PET bottle caps collected from the market, to a level where it can be used as a PET bottle cap product for non-carbonated beverages, without impairing the rigidity of the polyolefin-based recycled resin during the modification process, it is preferable to adjust the amount of the modifier so that both the flexural modulus, which indicates the rigidity of the resulting polyolefin-based resin molding material, and the environmental stress crack resistance (ESCR), which indicates the durability (stress crack resistance) of the polyolefin-based resin molding material, are increased in a well-balanced manner. Specifically, the amount of the modifier is adjusted so that the flexural modulus of the polyolefin resin molding material is preferably 900 MPa or more, more preferably 950 MPa or more, or so that the environmental stress crack resistance (ESCR) of the polyolefin resin molding material is preferably 45 hours or more, more preferably 50 hours or more. In most cases, by setting the amount of the modifier, which consists of polyolefin-based recovered resin and polyethylene-based resin obtained from PET bottle caps collected from the market, to 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more, a level of performance suitable for use in PET bottle cap products for non-carbonated beverages can be obtained. Furthermore, the performance of the resulting polyolefin resin molding material improves as the amount of the polyethylene resin modifier increases. Therefore, there is no particular upper limit on the amount of the modifier. However, in most cases, even if the amount of the modifier is limited to 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, relative to the total amount of the polyolefin-based recovered resin and the polyethylene resin modifier, it is still a sufficient amount to obtain a level of performance suitable for use in PET bottle cap products for non-carbonated beverages.

[0067] 6. Manufacturing of polyolefin-based resin molding materials The polyolefin-based resin molding material of the present invention is obtained by uniformly mixing, as essential components, the above-mentioned polyolefin-based recovered resin and the above-mentioned polyethylene-based resin modifier, and other components as needed, in accordance with conventional methods for manufacturing resin compositions. For example, pellets of polyolefin-based recovered resin and pellets of a modifier can be dry-blended or melt-blended, and other components can be added during the blending process in any order. In the case of dry blending, the pellets of polyolefin-based recovered resin and the pellets of the modifier are ultimately melt-blended in the molding machine. The blending method is appropriately selected according to the manufacturing process. In the case of melt blending, the resulting polyolefin-based resin molding material may be pelletized by processing it in a pelletizer.

[0068] The polyolefin resin molding material of the present invention may contain polymers other than olefins in accordance with conventional methods in order to further enhance various physical properties or to add other physical properties. It may also contain additives such as antioxidants (phenol-based, phosphorus-based, sulfur-based), ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, antifogging agents, antiblocking agents, processing aids, coloring pigments, crosslinking agents, foaming agents, inorganic or organic fillers, flame retardants, and nucleating agents that promote crystallization.

[0069] From the viewpoint of imparting suitable properties for PET bottle caps for non-carbonated beverages, the polyolefin resin molding material of the present invention preferably has a high content ratio of the modified material consisting of the polyolefin-based recovered resin and the polyethylene-based resin. Specifically, the total amount of the modified material consisting of the polyolefin-based recovered resin and the polyethylene-based resin is preferably 90% by mass or more of the total polyolefin resin molding material, more preferably 95% by mass or more, and even more preferably 97% by mass or more.

[0070] 7. Molding using polyolefin resin molding materials The polyolefin-based resin molding material of the present invention satisfies various properties, and therefore excels in moldability, high fluidity, odor, impact resistance, food safety, rigidity, and heat resistance. Consequently, it is suitable for applications such as containers and container lids that require these properties. In particular, PET bottle caps for non-carbonated beverages can be manufactured by using the polyolefin resin molding material of the present invention and molding it by injection molding or compression molding. It is preferable that the PET bottle caps for non-carbonated beverages be manufactured by continuous compression molding. Furthermore, the polyolefin resin molding material of the present invention can also be used for containers and lids for food and beverages such as edible oils, spices such as wasabi, seasonings, and alcoholic beverages, as well as for containers and lids for cosmetics and hair creams, and is mainly molded by injection molding. [Examples]

[0071] The present invention will be described in more detail in the following examples and comparative examples, but the present invention is not limited thereto.

[0072] [Measurement Method and Evaluation Method] The measurement and evaluation methods used in the 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 was 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 was measured in accordance with JIS-K6922-2:1997. (3) Density: Measured in accordance with JIS-K6922-1,2:1997.

[0073] (4) Comonomer Sequence Distribution (CSD) A ): CSD (CSD) of component (A) of the modifier made of polyethylene resin A Based on the description in JCRandall, JMS-REV.MACROMOL.CHEM.PHYS., C29(2&3), pp. 201-317 (1989), 13 The measurement was performed using 1C-NMR spectroscopy. Specifically, the ethylene-ethylene chain number, comonomer-comonomer chain number, and ethylene-comonomer chain number were measured using a JEOL-GSX400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd., and the CSD was determined from these values.A This was obtained using equation (a). CSD = 4 × [EE][CC] / [EC] 2 Formula (a)

[0074] Specifically, the measurements were taken under the following conditions. Instrument: JEOL-GSX400 manufactured by JEOL Ltd., pulse width: 8.0 μsec (flip angle = 40°), pulse repetition time: 5 seconds, number of integrations: 5000 or more, solvent and internal standard: 1,2,4-trichlorobenzene / benzene-d6 / hexamethyldisiloxane (mixing ratio: 30 / 10 / 1), measurement temperature: 120°C, sample concentration: 0.3 g / ml. The spectrum obtained from 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)

[0075] (5) Number of short chain branches with 1 to 20 carbon atoms per 1,000 carbon atoms in the main chain (SCB) A : Component (A) of the modifier made of polyethylene resin 13 The C-NMR spectrum measurement was used to calculate the above CSD. 13 The measurements were performed under the same conditions as for 1C-NMR spectroscopy, and the results were 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)

[0076] (6) Breaking time at 1.9 MPa by full-notch creep test (FNCT): Measured in accordance with JIS-K6774:1998, at a temperature of 80°C, using a 1% aqueous solution of Kao Corporation's detergent Emal as the test solution. (7) Charpy impact strength: Measured in accordance with JIS-K7111-1:2006. (8) Flexural modulus: A 4mm x 10mm x 80mm plate-like body, injection-molded at 210°C, was used as a test specimen, and the modulus was measured in accordance with JIS-K6922-2:1997.

[0077] (9) Viscosity at melt: Using an Intesco capillary rheometer, measured at 190°C with a 1 mm diameter capillary and L / D: 35, at a shear rate of 400 sec. -1 The melt viscosity was measured. (10) ESCR: Measurement was performed in accordance with ASTM D 1693, at a temperature of 50°C, using a 10 vol% aqueous solution of SIGMA-ALDRICH IGEPAL CO-630 as the working solution. (11) Comprehensive evaluation of polyolefin resin molding materials The suitability of polyolefin resin molding materials for PET bottle caps for non-carbonated beverages was evaluated according to the following criteria. [Evaluation Criteria] ○ (Good): The flexural modulus is 900 MPa or higher, and the ESCR is 45 hours or higher. × (Defective): Flexural modulus is less than 900 MPa, or ESCR is less than 45 hours.

[0078] [Preparation of Modifier A] (Manufacturing of catalysts) 115 g of magnesium ethoxide, 151 g of tri-n-butoxymonol titanium, and 37 g of n-butanol were mixed at 150°C for 6 hours until homogenized. Next, the temperature was lowered to 60°C, and n-hexane was added to form a homogeneous solution. Then, 457 g of ethylaluminum sesquichloride was added dropwise at a predetermined temperature and stirred for 1 hour. The resulting precipitate was washed with n-hexane to obtain 210 g of catalyst components. The obtained solid was dried to obtain a powder. This powder contained 11.0% by mass of Mg and 10.5% by mass of Ti.

[0079] (Production of polymers) As the first-stage reactor, a first-stage polymerizer with an internal volume of 200 liters was supplied with 1.5 g / hr of the solid catalyst component obtained in the above (catalyst production) from the catalyst supply line, and 40 mmol / hr of triethylaluminum from the organometallic compound supply line. The polymerization contents were discharged at the required rate, and the polymerization solvent (n-hexane) was supplied at a rate of 70 (l / hr), hydrogen at 209 (mg / hr), ethylene at 17.3 (kg / hr), and 1-butene at 0.59 (kg / hr) at 70°C. 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 collected, and the polymer was recovered and its physical properties were measured. The results are designated as "Component (A)". The slurry polymerization product generated in the first-stage reactor was directly introduced in its entirety into the second-stage reactor, which has an internal volume of 400 liters, through a continuous tube with an inner diameter of 50 mm. The polymer contents were discharged at the required rate, while the polymerization solvent (n-hexane) was supplied at a rate of 100 L / hr, hydrogen at 30.2 g / hr, and ethylene at 42.8 kg / hr at 82°C. The second-stage polymerization was carried out continuously under conditions of a total pressure of 1.1 MPa and an average residence time of 1.71 hr. The polymerization product discharged from the second-stage reactor was introduced into a flushing tank, and the polymerization product was continuously withdrawn to remove unreacted gas from the degassing line. After steam stripping the obtained polymer, it was granulated in a pelletizer and its physical properties were evaluated. The modifier A obtained by the above method met the requirements for the modifier 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 were determined by calculation based on the addition rule, using the physical properties of the final product, the polyethylene composition, and the physical properties of Component (A) obtained in the first-stage reactor.

[0080] [Example 1] As a polyolefin-based recycled resin made from PET bottle caps collected from the market, Shin-ei Kasei Co., Ltd.'s recycled pellets (MFR: 1.4g / 10 min, HLMFR: 147g / 10 min, HLMFR / MFR: 105, Density: 0.965g / cm³) 3 FNCT: 23 hours, Charpy impact strength: 8KJ / m 2 (Flexural modulus: 1050PMa, ESCR: 30 hours) and the above-mentioned modified material A (MFR: 0.8g / 10 min, HLMFR: 130g / 10 min, HLMFR / MFR: 162.5, Density: 0.962g / cm³) 3 FNCT: 170 hours, Charpy impact strength: 11KJ / m 2 Pellets with a flexural modulus of elasticity of 1000 PMa and an ESCR of 250 hours were dry-blended in a 60:40 mass ratio (polyolefin-based recovered resin:modifier), and 70 g of the mixture was then placed into a Toyo Seiki Co., Ltd. Laboplast Mill (model: roller mixer R100) equipped with a 100 ml capacity small mixer. Simultaneously, 0.14 g of antioxidant B225 was added, and after preheating at 190°C for 3 minutes, the mixture was kneaded at 190°C and 40 rpm for 2 minutes to perform a melt blend. The physical properties of the obtained resin molding material were: MFR: 1.1 g / 10 min, HLMFR: 137 g / 10 min, HLMFR / MFR: 125, Density: 0.964 g / cm³ 3 Charpy impact strength: 9KJ / m 2 The flexural modulus was 1020PMa and the ESCR was 83 hours, which are physical properties suitable for use as a PET bottle cap for non-carbonated beverages.

[0081] [Example 2] The test was conducted in the same manner as in Example 1, except that the mass ratio of the polyolefin-based recovered resin to the modifier was changed to 20:80. The physical properties of the obtained resin molding material were: MFR: 0.8 g / 10 min, HLMFR: 132 g / 10 min, HLMFR / MFR: 165, Density: 0.963 g / cm³ 3 Charpy impact strength: 10KJ / m 2The flexural modulus was 1000 PMa and the ESCR was 150 hours, which are physical properties suitable for use as a PET bottle cap for non-carbonated beverages.

[0082] [Comparative Example 1] As the polyolefin-based recycled resin recycled from PET bottle caps collected from the market, we used recycled pellets from Shin-ei Kasei Co., Ltd., which were used in Example 1, and as a modifier, we used polyethylene resin HJ560 from Nippon Polyethylene Co., Ltd., a general injection molding grade (MFR: 7.1g / 10 min, HLMFR: 227g / 10 min, HLMFR / MFR: 32, density: 0.964g / cm³). 3 FNCT: 15 hours, Charpy impact strength: 6KJ / m 2 Pellets with a flexural modulus of elasticity of 1200 MPa and an ESCR of 21 hours were dry-blended in a 60:40 mass ratio (polyolefin-based recovered resin:modifier), and 70 g of the mixture was then placed into a Toyo Seiki Co., Ltd. Laboplast Mill (model: roller mixer R100) equipped with a 100 ml capacity small mixer. Simultaneously, 0.14 g of antioxidant B225 was added, and after preheating at 190°C for 3 minutes, the mixture was kneaded at 190°C and 40 rpm for 2 minutes to perform a melt blend. The physical properties of the obtained resin molding material were: MFR: 3.7 g / 10 min, HLMFR: 185 g / 10 min, HLMFR / MFR: 50, Density: 0.965 g / cm³ 3 Charpy impact strength: 7KJ / m 2 With a flexural modulus of 1080 MPa and an ESCR of 25 hours, the durability (stress crack resistance) indicated by the ESCR is insufficient, making it unsuitable for use as a PET bottle cap for non-carbonated beverages.

[0083] [Comparative Example 2] As the polyolefin-based recycled resin recycled from PET bottle caps collected in the market, we used recycled pellets from Shin-ei Kasei Co., Ltd., which were used in Example 1, and as a modifier, we used polyethylene resin KS571 (MFR: 12g / 10 min, HLMFR: no data, HLMFR / MFR: no data, density: 0.907g / cm³). 3Pellets with FNCT: over 500 hours, Charpy impact strength: too soft to break, flexural modulus: 110 MPa, ESCR: over 1000 hours were dry-blended with polyolefin-based recovered resin (modifier) ​​in a mass ratio of 80:20. 70g of this mixture was then placed into a Toyo Seiki Co., Ltd. Laboplast Mill (model: Roller Mixer R100) equipped with a 100ml capacity mini-mixer. Simultaneously, 0.14g of antioxidant B225 was added. After preheating at 190°C for 3 minutes, the mixture was kneaded at 190°C and 40rpm for 2 minutes to perform a melt blend. The physical properties of the obtained resin molding material were: MFR: 1.8 g / 10 min, HLMFR: 170 g / 10 min, HLMFR / MFR: 94, Density: 0.953 g / cm³ 3 The flexural modulus was 700 MPa and the ESCR was 140 hours. While the durability (stress crack resistance) indicated by the ESCR was good, the stiffness indicated by the flexural modulus was significantly reduced, making it unsuitable as a PET bottle cap for non-carbonated beverages.

[0084] [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. Furthermore, the properties of the polyolefin-based recovered resin, the modifier used in each example and comparative example, and the modified polyolefin-based resin molding material obtained in each example and comparative example are shown in Table 2 below. The modifiers used in Examples 1 and 2 consist of the specific components (A) and (B) described above and are polyethylene-based resins that satisfy properties (1) to (4). Because they are excellent in various physical properties required for PET bottle caps, including stiffness expressed as flexural modulus and durability expressed as FNCT, the resin molding materials obtained in Examples 1 and 2 were able to improve durability (stress crack resistance) to the level required for typical non-carbonated beverage PET bottle cap products without lowering the various physical properties of the pre-modified polyolefin-based recovered resin from the level required for PET bottle caps. In contrast, the modifier used in Comparative Example 1 did not consist of components (A) and (B), and therefore had a low FNCT. As a result, the ESCR of the resin molding material obtained in Comparative Example 1 was also low, and its durability (stress crack resistance) was insufficient. Furthermore, the modifier used in Comparative Example 2 did not consist of components (A) and (B), and had a lower flexural modulus. As a result, the flexural modulus of the resin molding material obtained in Comparative Example 2 was also lower, and the rigidity was significantly reduced.

[0085] [Table 1]

[0086] [Table 2]

Claims

1. This invention includes a polyolefin-based recycled resin obtained by homogenizing polyolefin-based resin caps from the market of PET bottles, and a modified material consisting of the following polyethylene-based resins. A polyolefin-based resin molding material in which the content of the modifier is 1 to 99% by mass relative to the total amount of the polyolefin-based recovered resin and the modifier. [Modifier made from polyethylene resin] A modifier made of a polyethylene resin that contains 20% to 40% by mass of component (A) and 60% to 80% by mass of component (B) as an ethylene polymer, and satisfies the following characteristics (1) to (4). Components (A): HLMFR of 0.05–5.0 g / 10 min, density of 0.910–0.935 g / cm³ ３ and １３ The value of CSD (comonomer sequence distribution) obtained from the measured C-NMR spectrum using formula (a) (CSD Ａ ) Ethylene polymers with a ratio of 0.0 to 3.0 CSD = 4×[EE][CC] / [EC] ２ Formula (a) (In formula (a), [EE] represents the ethylene-ethylene chain number, [CC] represents the comonomer-comonomer chain number, and [EC] represents the ethylene-comonomer chain number.) Components (B): MFR of 100 g / 10 min or more and less than 600 g / 10 min, density of 0.960 g / cm³ ３ 0.980g / cm or more ３ Ethylene polymers less than Characteristics (1): The melt flow rate (MFR) at a temperature of 190°C and a load of 2.16 kg is 0.2 g / 10 min or more and 3.0 g / 10 min or less, the high-load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg is 70 g / 10 min or more and less than 180 g / 10 min, and the HLMFR / MFR ratio is 50 to 500. Characteristic (2): Density is 0.955 g / cm³ ３ 0.970g / cm or more ３ The following is Characteristic (3): The full notch creep test at 80°C and 1.9 MPa has a fracture time (FNCT) of 100 hours or more. Characteristic (4): Charpy impact strength is 9.0 KJ / m ２ or more

2. The polyolefin-based resin molding material according to claim 1, wherein the flexural modulus of the polyolefin-based resin molding material is 900 MPa or more.

3. The polyolefin-based resin molding material according to claim 1 or 2, wherein the environmental stress crack resistance (ESCR) of the polyolefin-based resin molding material is 45 hours or more.

4. The modified material, comprising the polyethylene resin, further satisfies the following characteristics (5) to (6), and is a polyolefin resin molding material according to any one of claims 1 to 3. Characteristic (5): The flexural modulus is 900 to 1500 MPa. Characteristics (6): 190°C, shear rate 400 sec －１ The viscosity at melting is 200 to 1000 Pa·s.

5. The polyolefin resin molding material according to any one of claims 1 to 4, characterized in that at least one of the ethylene polymer components (A) and (B) is obtained by multi-stage polymerization combining at least two polymerization reactors in the presence of a polymerization catalyst, in which an ethylene homopolymer is polymerized in at least one of the two polymerization reactors, and an ethylene copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is polymerized in at least one of the two polymerization reactors.

6. The polymerization catalyst for the ethylene polymer is of the general formula Mg(OR ２ ) ｍ X ２ ２－ｍ (In the formula, R ２ X represents alkyl, aryl, or cycloalkyl groups. ２ Compounds represented by the general formula Ti(OR) (where m is 1 or 2) ３ ) ｎ X ３ ４－ｎ (In the formula, R ３ X represents alkyl, aryl, or cycloalkyl groups. ３ A homogeneous hydrocarbon solution containing a compound represented by the general formula AlR (where is a halogen atom and n is 1, 2, or 3) is provided. １ ｌ X １ ３－ｌ (In the formula, R １ X represents alkyl, aryl, or cycloalkyl groups. １ The polyolefin resin molding material according to claim 5, characterized in that it is a catalyst comprising a hydrocarbon-insoluble solid catalyst obtained by treatment with an organic aluminum halide compound (where l represents a halogen atom and l represents a number 1 ≤ l ≤ 2) and an organic aluminum compound.

7. A polyolefin-based resin molding material according to any one of claims 1 to 6, used for molding PET bottle caps for non-carbonated beverages.

8. A polyolefin-based resin molding material according to any one of claims 1 to 6, used for continuous compression molding of PET bottle caps for non-carbonated beverages.

9. A PET bottle cap for non-carbonated beverages, formed by molding a polyolefin resin molding material according to any one of claims 1 to 6.

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