Method for evaluating the injection physical properties of plastic resins, and polyethylene resins for injection molding

Abstract

The present invention relates to a method for evaluating injection physical properties of a plastic resin, and a polyethylene resin suitable for an injection molding process, and more particularly, the present invention relates to a new method for evaluating injection physical properties of a plastic resin, in which the injection suitability of the plastic resin and the injection pressure in the injection process can be accurately derived by using the values of the physical properties measured by using a resin sample when a specific plastic resin is processed through an injection process, and a polyethylene resin suitable for an injection molding.

Description

[0001] This application is a divisional application of patent application No. 201880054778.7 (International Application No.: PCT / KR2018 / 009609), filed on August 21, 2018, entitled "Method for evaluating the injection physical properties of plastic resin, and polyethylene resin for injection molding". Technical Field

[0002] Cross Reference to Related Applications

[0003] This application claims the benefit of filing dates of Korean Patent Application No. 10-2017-0106308, filed with the Korean Intellectual Property Office on August 22, 2017, and Korean Patent Application No. 10-2017-0122819, filed with the Korean Intellectual Property Office on September 22, 2017, the disclosures of which are incorporated herein by reference in their entirety.

[0004] This invention relates to a method for evaluating the injection physical properties of plastic resins, and a polyethylene resin suitable for injection molding processes. More specifically, this invention relates to a novel method for evaluating the injection physical properties of plastic resins, which, when a specific plastic resin is processed by an injection process, can accurately deduce the injection suitability of the plastic resin and the injection pressure in the injection process by using the values ​​of physical properties measured using resin samples. This invention also relates to a polyethylene resin suitable for injection molding processes under specific conditions. Background Technology

[0005] Plastic is a polymer compound that can be molded by heating and / or pressing, and is an easy-to-process polymer. Plastic melts when heat is applied and returns to a solid state if the temperature is lowered sufficiently.

[0006] Because plastics are easy to process into various forms and some of them can be recycled, a wide variety of plastic resin molded products are used in modern society.

[0007] Typically, such plastics are obtained by polymerizing monomeric compounds, and the polymerized resin or resin composition can be processed into granules and stored, and then molded into products by various methods depending on the application.

[0008] Injection molding is a type of plastic molding technology in which plastic resin, prepared in the form of beads, granules, or flakes, is placed into an injection molding machine and injected to be processed into the desired shape.

[0009] The injection molding machine includes a hopper for injecting plastic resin as raw material, a heating unit for heating and melting the plastic resin, a screw for extruding the molten plastic resin, and a mold for molding it into a desired shape.

[0010] Plastic resin, processed in the form of beads, granules, or flakes, is weighed at a fixed quantity from a hopper and fed into a heating unit, where it melts while being propelled by a screw. The molten plastic resin is then injected into the cavity of a mold through an injection nozzle. The plastic resin injected into the mold is then further cured to achieve the final desired product form.

[0011] When plastic resin is introduced into an injection mold using a conventional injection molding process, the material adjacent to the cavity wall inside the mold immediately begins to solidify as the liquid plastic resin cools to a temperature below the material's non-flowing temperature.

[0012] As plastic resin flows through the mold, a boundary layer forms against the side of the mold. As more resin is added into the mold, this boundary layer thickens, eventually sealing off the resin's flow path and preventing other materials from entering the mold. Therefore, it is necessary to determine the injection pressure during injection and to ascertain the suitability of the injection molding process.

[0013] In other words, when the injection pressure is below a certain range, the problem is that the plastic resin cannot be injected into the mold for the reasons mentioned above. When the injection pressure is above a certain range, processability may deteriorate. In the past, there were only methods to confirm the injection pressure by directly injecting granular plastic resin, and there was no method to predict the injection pressure or determine the suitability of injection molding before injection molding. Summary of the Invention

[0014] [Technical Issues]

[0015] One object of the present invention is to provide a novel method for evaluating the injection physical properties of plastic resins, which can accurately determine the injection suitability of plastic resins by using the values ​​of physical properties measured using resin samples when a particular plastic resin is processed by an injection process.

[0016] Another object of the present invention is to provide a polyethylene resin suitable for injection molding processes under specific conditions.

[0017] [Technical Solution]

[0018] In one aspect of the present invention, a method for evaluating the injection physical properties of plastic resins is provided, comprising the following steps:

[0019] Measure the number-average molecular weight of plastic resin samples;

[0020] Calculate the portion of low molecular weight molecules (below 3,500 g / mol) in the molecular weight distribution of the plastic resin sample; and

[0021] The injection suitability of plastic resins can be predicted by the number average molecular weight and the fraction of low molecular weight molecules.

[0022] In another aspect of the invention, a polyethylene resin for injection molding is provided, wherein the number average molecular weight is 14,500 g / mol or less; and the fraction of low molecular weight molecules having a molecular weight of 3,500 g / mol or less is 4% or more.

[0023] In another aspect of the present invention, a method for evaluating the injection physical properties of plastic resins is provided, comprising the following steps:

[0024] Measure the melt index (MI) value of the plastic resin sample;

[0025] Measure the steady-state flow viscosity of the plastic resin sample; and

[0026] Based on the viscosity model equation, the shear thinning index value can be derived from the steady-state flow viscosity value; and

[0027] Injection pressure is predicted using melt index and shear thinning index values.

[0028] [Beneficial Effects]

[0029] According to the present invention, even without injecting the plastic resin into the actual injection molding process, the injection suitability and the injection pressure required for the actual injection process can be accurately determined solely from the physical properties measured by the sample, thus being economical in terms of both time and money. Detailed Implementation

[0030] The technical terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the scope of the invention. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms. It should be understood that, herein, the terms “comprising,” “including,” “having,” etc., are used to specify the presence of said features, integers, steps, components, or combinations thereof, but do not exclude the prior presence or addition of one or more other features, integers, steps, components, or combinations thereof.

[0031] Since various modifications can be made to the present invention, and various forms of the invention can exist, specific embodiments thereof are shown and will be described in detail below. However, it should be understood that these are not intended to limit the invention to the specific disclosure, and the invention includes all modifications, equivalents, or substitutions thereof without departing from the spirit and scope of the invention.

[0032] Throughout this specification, the term "plastic resin" is a concept that includes both thermosetting and thermoplastic plastics, and refers to polymeric plastic resins that can be processed by injection molding.

[0033] The embodiments of the present invention will be described in detail below.

[0034] A method for evaluating the injection physical properties of plastic resin according to an embodiment of the present invention includes the following steps:

[0035] Measure the number-average molecular weight of plastic resin samples;

[0036] Calculate the portion of low molecular weight molecules (below 3,500 g / mol) in the molecular weight distribution of the plastic resin sample; and

[0037] The injection suitability of plastic resins can be predicted by the number average molecular weight and the fraction of low molecular weight molecules.

[0038] The inventors discovered that, after assuming that the injection pressure in the injection molding process of plastic resin is related to the molecular weight characteristics of the corresponding plastic resin, the actual injection suitability can be accurately determined by factors related to a specific molecular weight that can be measured using a sample of the plastic resin, thus completing the present invention.

[0039] According to one embodiment of the present invention, the number average molecular weight of the plastic resin sample is preferably from about 10,000 to about 20,000 g / mol.

[0040] Furthermore, the portion of low molecular weight molecules having a molecular weight of 3,500 g / mol or less is preferably about 1 to about 10%.

[0041] Furthermore, under injection process conditions of approximately 240°C and approximately 650 bar, the injection pressure of the plastic resin can be less than approximately 1600 Pa, preferably approximately 1000 to approximately 1600 Pa, or more than approximately 1200 Pa and less than approximately 1600 Pa.

[0042] According to another embodiment of the invention, the predictive suitability for injection can be determined as follows: when the number average molecular weight of the plastic resin sample is 14,500 g / mol or less and the fraction of low molecular weight molecules with a molecular weight of 3,500 g / mol or less is 4% or more, it is suitable for injection.

[0043] If the injection pressure is below a certain range, the problem is that the plastic resin cannot be injected into the mold, and if the injection pressure is above a certain range, the processability may deteriorate. Therefore, in typical plastic resin injection molding processes, it is desirable to adjust the injection pressure to less than about 1600 Pa under injection process conditions of about 240°C and about 650 bar.

[0044] This injection pressure has the characteristic of varying according to the rheological properties of the plastic resin. When the number-average molecular weight is below 14,500 g / mol and the fraction of low molecular weight molecules with a molecular weight below 3,500 g / mol is above 4%, it is found that under injection process conditions of about 240°C and about 650 bar, the injection pressure is less than about 1600 Pa, or more than about 1200 Pa and less than about 1600 Pa, and the injection suitability is excellent. If any of the above conditions are not met, it is found that under injection process conditions of about 240°C and about 650 bar, the injection pressure exceeds about 1600 Pa, and the injection suitability decreases.

[0045] That is, when using the above method, only the molecular weight characteristics of the sample can be measured without directly injecting plastic resin into the injection molding process, thereby making it easy to determine the injection suitability under specific conditions.

[0046] Meanwhile, according to another embodiment of the present invention, a polyethylene resin for injection molding is provided, wherein the number average molecular weight is 14,500 g / mol or less; and the portion of low molecular weight molecules having a molecular weight of 3,500 g / mol or less is 4% or more.

[0047] Polyethylene resin is well-suited for injection molding because, as mentioned above, the injection pressure is less than about 1600 Pa under injection process conditions of about 240°C and about 650 bar.

[0048] The polyolefin resin may have a melt index (MI) value of approximately 0.1 to approximately 1.5 g / 10 min, measured according to ASTM 1238 at 190°C and a load of 2.16 kg. The density value of the plastic resin, measured according to ASTM 1505, may be approximately 0.94 to approximately 0.96 g / cm³. 3 .

[0049] The above-mentioned polyethylene resin can be manufactured using the following metallocene catalysts.

[0050] The metallocene catalysts that can be used include one or more first metallocene compounds represented by the following chemical formula 1; and a mixture of one or more second metallocene compounds represented by the following chemical formula 3.

[0051] [Chemical Formula 1]

[0052]

[0053] In chemical formula 1,

[0054] M is a group 4 transition metal;

[0055] B1 is carbon, silicon, or germanium;

[0056] Q1 and Q2 may be the same as or different from each other, and each is independently hydrogen, halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, C7-C20 alkylaryl, C7-C20 arylalkyl, C1-C20 alkoxy, C2-C20 alkoxyalkyl, C3-C20 heterocyclic alkyl or C5-C20 heteroaryl;

[0057] X1 and X2 may be the same as or different from each other, and each is independently a halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, nitro, amide, C1-C20 alkylsilyl, C1-C20 alkoxy or C1-C20 sulfonate group;

[0058] C1 and C2 may be the same or different, and each is independently represented by one of the following chemical formulas 2a, 2b, 2c or 2d, provided that at least one of C1 and C2 is represented by chemical formula 2a;

[0059] [Chemical Formula 2a]

[0060]

[0061] [Chemical Formula 2b]

[0062]

[0063] [Chemical formula 2c]

[0064]

[0065] [Chemical formula 2d]

[0066]

[0067] In chemical formulas 2a, 2b, 2c, and 2d,

[0068] R1 to R 28 They may be the same as or different from each other, and each independently is hydrogen, halogen, C1-C20 alkyl, C2-C20 alkenyl, C1-C20 alkylsilyl, C1-C20 silylalkyl, C1-C20 alkoxysilyl, C1-C20 ether, C1-C20 silyl ether, C1-C20 alkoxy, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl.

[0069] R'1 to R'3 may be the same as or different from each other, and each is independently hydrogen, halogen, C1-C20 alkyl, C2-C20 alkenyl or C6-C20 aryl, and

[0070] R1 to R 28Two or more adjacent groups can be linked together to form substituted or unsubstituted aliphatic or aromatic rings.

[0071] [Chemical Formula 3]

[0072]

[0073] In chemical formula 3,

[0074] R 31 To R 38 At least one of them is -(CH2)n-OR (where R is a straight-chain or branched C1-C6 alkyl group, and n is an integer from 2 to 4).

[0075] The remaining functional groups may be the same as or different from each other, and are independently selected from hydrogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl, or two or more adjacent groups may be connected to each other to form an aliphatic or aromatic ring substituted or unsubstituted with a C1-C10 hydrocarbon group.

[0076] Q3 and Q4 may be the same as or different from each other and are each independently halogenated or C1-C20 alkyl;

[0077] M' is a group 4 transition metal.

[0078] X3 and X4 may be the same as or different from each other and are each independently a halogen or a C1-C20 alkyl group, and

[0079] m is an integer that is either 0 or 1.

[0080] The individual substituents in the above chemical formulas will be described in more detail below.

[0081] The C1-20 alkyl group may include straight-chain or branched alkyl groups, and specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, etc.

[0082] The C2-20 alkenyl group may include straight-chain or branched alkenyl groups, and specific examples include, but are not limited to, allyl, vinyl, propenyl, butenyl, pentenyl, etc.

[0083] The C6-20 aryl group includes monocyclic or fused-ring aryl groups, and specific examples include, but are not limited to, phenyl, biphenyl, naphthyl, phenanthryl, fluorene, etc.

[0084] The C5-20 heteroaryl group may include monocyclic or fused-ring heteroaryl groups, and specific examples include, but are not limited to, carbazolyl, pyridinyl, quinolinyl, isoquinolinyl, thiophenyl, furanyl, imidazolyl, oxazolyl, thiazolyl, triazinyl, tetrahydropyranyl, tetrahydrofuranyl, etc.

[0085] The C1-20 alkoxy group may include, but is not limited to, methoxy, ethoxy, phenoxy, cyclohexyloxy, etc.

[0086] The C1-C20 alkylsilyl groups may include, but are not limited to, methylsilyl, dimethylsilyl, trimethylsilyl, etc.

[0087] The C1-C20 silyl alkyl group may include, but is not limited to, silyl methyl, dimethyl silyl methyl (-CH2-Si(CH3)2H), trimethyl silyl methyl (-CH2-Si(CH3)3), etc.

[0088] The group 4 transition metals may include, but are not limited to, titanium, zirconium, hafnium, etc.

[0089] In the metallocene compounds of formula 1, preferably, R1 to R2 in formulas 2a, 2b, 2c and 2d. 28 Each of these groups can be hydrogen, halogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, ethylidene, propyleneide, butylidene, phenyl, benzyl, naphthyl, halogen group, ether group, trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, triisopropylsilyl, trimethylsilylmethyl, dimethyl ether, tert-butyldimethylsilyl ether, methoxy, ethoxy, or tert-butoxyhexyl, but is not limited thereto.

[0090] In chemical formula 1, Q1 to Q2 are hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, methoxymethyl, tert-butoxymethyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl, tert-butoxyhexyl, tetrahydropyranyl, or tetrahydrofuranyl, but are not limited thereto.

[0091] In chemical formula 1, B1 is preferably silicon (Si), but is not limited thereto.

[0092] In particular, metallocene compounds of formula 1 are characterized by the fact that the substituents of formula 2a contain at least one or more C1-C20 silyl alkyl groups, such as trimethylsilylmethyl.

[0093] More specifically, the indene derivatives of formula 2a have relatively low electron density compared to indene-indole derivatives or fluorenyl derivatives, and include sterically hindered silyl alkyl groups due to steric hindrance and electron density factors. Compared to metallocene compounds with similar structures, they can polymerize olefin polymers with relatively low molecular weights with high activity.

[0094] In addition, indole derivatives represented by chemical formula 2b, fluorenyl derivatives represented by chemical formula 2c, and indole derivatives represented by chemical formula 2d can form cross-linked structures via bridging and have non-shared electron pairs that can act as Lewis bases in the ligand structure, thereby exhibiting high polymerization activity.

[0095] According to one embodiment of the present invention, specific examples of the functional group represented by chemical formula 2a may include compounds represented by one of the following structural formulas, but the present invention is not limited thereto.

[0096]

[0097]

[0098] According to one embodiment of the present invention, specific examples of the functional group represented by chemical formula 2b may include compounds represented by one of the following structural formulas, but the present invention is not limited thereto.

[0099]

[0100]

[0101] According to one embodiment of the present invention, specific examples of the functional group represented by chemical formula 2c may include compounds represented by one of the following structural formulas, but the present invention is not limited thereto.

[0102]

[0103]

[0104] According to one embodiment of the present invention, specific examples of functional groups represented by chemical formula 2d may include compounds represented by one of the following structural formulas, but the present invention is not limited thereto.

[0105]

[0106]

[0107] According to one embodiment of the present invention, specific examples of metallocene compounds represented by chemical formula 1 may include compounds represented by one of the following structural formulas, but the present invention is not limited thereto.

[0108]

[0109]

[0110] The first metallocene compound of formula 1 exhibits excellent activity and can polymerize polyethylene with high molecular weight. In particular, it can exhibit high polymerization activity even when loaded onto a support, thus enabling the preparation of high molecular weight polyethylene.

[0111] According to one embodiment, the metallocene compound of Formula 1 can be obtained by connecting an indene derivative and a cyclopentadiene derivative with a bridging compound to prepare a ligand compound, and then placing a metal precursor compound therein for metallization, but is not limited thereto.

[0112] The second metallocene compound contained in the hybrid metallocene catalyst can be represented by the following chemical formula 3.

[0113] [Chemical Formula 3]

[0114]

[0115] In chemical formula 3,

[0116] R 31 To R 38 At least one of them is -(CH2). n -OR (where R is a straight-chain or branched C1-C6 alkyl group and n is an integer from 2 to 4), the rest being the same or different from each other, and independently being a functional group selected from hydrogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, C7-C20 alkylaryl, and C7-C20 arylalkyl, or two or more adjacent groups may be connected to each other to form an aliphatic or aromatic ring substituted or unsubstituted with a C1-C10 hydrocarbon group.

[0117] Q3 and Q4 may be the same as or different from each other, and each is independently a halogen or a C1-C20 alkyl group;

[0118] M' is a group 4 transition metal.

[0119] X3 and X4 may be the same as or different from each other, and each is independently a halogen or a C1-C20 alkyl group, and

[0120] m is an integer that is either 0 or 1.

[0121] In metallocene compounds of formula 3, with -(CH2) n The substituent -OR (where R is a linear branched C1-C6 alkyl group and n is an integer from 2 to 4) is introduced into the substituent of cyclopentadiene (Cp) or its derivatives. During the preparation of polyethylene using comonomers, it exhibits lower comonomer conversion compared to other Cp-based catalysts that do not contain said substituents, and thus can be used to prepare medium or low molecular weight polyethylene with controllable copolymerization degree or comonomer distribution.

[0122] As a more specific example, when a second metallocene compound of formula 3 is used as a hybrid catalyst along with other metallocene compounds to prepare polyethylene with a high molecular weight region, the polyethylene in the high molecular weight region exhibits high copolymerization due to the other metallocene compounds, while the polyethylene in the low molecular weight region exhibits low copolymerization due to the effect of the second metallocene compound of formula 3. Therefore, it is highly advantageous to polymerize polyethylene with a BOCD (broadly orthogonal comonomer distribution) structure, in which the comonomer content is concentrated on the high molecular weight backbone, i.e., the side branch content increases towards the higher molecular weight side.

[0123] The substituents defined by chemical formula 3 will be described in more detail below.

[0124] The C1-C20 alkyl group may include straight-chain or branched alkyl groups.

[0125] The aryl group is preferably a C6-C20 aromatic ring, and specific examples include, but are not limited to, phenyl, naphthyl, anthracene, pyridyl, dimethylaniline, and anisole.

[0126] The alkyl aryl group refers to an aryl group in which one or more straight-chain or branched C1-C20 alkyl groups are introduced, and the aryl alkyl group refers to a straight-chain or branched alkyl group in which one or more C6-C20 aryl groups are introduced.

[0127] The hydrocarbon group refers to a monovalent hydrocarbon compound, and examples of such groups include alkyl, alkenyl, aryl, alkylaryl, arylalkyl, etc.

[0128] The halogen groups refer to fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).

[0129] The group 4 transition metal specified as M' can be Ti (titanium), Zr (zirconium), hafnium (Hf), etc., but is not limited to these.

[0130] Q3 and Q4 can preferably be C1-C20 alkyl, more preferably methyl, ethyl or propyl.

[0131] X3 and X4 are preferably halogen groups, and more preferably Cl.

[0132] One embodiment of the metallocene compound of the present invention has the following characteristic: R in chemical formula 3 31 To R 38One or more of them are -(CH2)n-OR (where R is a straight-chain or branched C1-C6 alkyl group, and n is an integer from 2 to 4). In Formula 3, -(CH2)n-OR may preferably be tert-butoxybutyl. More preferably, each of the two cyclopentadiene (Cp) derivatives contains a -(CH2)n-OR group, or only one of the Cp derivatives may contain a -(CH2)n-OR group, and the -(CH2)n-OR group may be tert-butoxybutyl.

[0133] When a metallocene compound with this structure is loaded onto a support, the -(CH2)n-OR group in the substituent can form a covalent bond through close interaction with the silanol group on the silica surface used as the support, thus enabling stable loading polymerization.

[0134] Metallocene compounds of chemical formula 3 can be more specifically represented by the following chemical formulas 3-1 to 3-4.

[0135] [Chemical Formula 3-1]

[0136]

[0137] [Chemical Formula 3-2]

[0138]

[0139] [Chemical Formula 3-3]

[0140]

[0141] [Chemical Formula 3-4]

[0142]

[0143] In chemical formulas 3-1 to 3-4, R 31 To R 38 Q3 to Q4, M', and X3 to X4 are the same as those defined in Formula 3, R' and R" are the same as or different from each other, and each is independently a C1-C10 hydrocarbon group.

[0144] The structure of chemical formula 3-1 is the case where m is 0 in chemical formula 3. It has the following structure: the two cyclopentadiene (Cp) groups are not cross-linked, and R... 31 To R 38 Any one or more substituents are -(CH2)n-OR.

[0145] The structure of chemical formula 3-2 is the case where m is 1 in chemical formula 3. It has the following structure: two Cp groups are cross-linked through a SiQ3Q4 bridge, and R... 31 To R 38Any one or more substituents are -(CH2)n-OR.

[0146] The structure of chemical formula 3-3 is the case where m is 0 in chemical formula 3. It is a structure in which the two indenyl groups formed by linking adjacent substituents in the Cp group are not cross-linked. The substituent R of the indenyl group... 31 R 32 R 35 and R 36 Any one or more substituents are -(CH2)n-OR, and each indenyl group can be substituted with a C1-C10 hydrocarbon group (R',R").

[0147] The structure of chemical formula 3-4 is the case where m is 1 in chemical formula 3. It is a structure in which two indenyl groups, formed by linking adjacent substituents in the Cp group, are cross-linked via a SiQ3Q4 bridge. The substituent R of the indenyl group... 31 R 32 R 35 and R 36 Any one or more substituents are -(CH2)n-OR, and each indenyl group can be substituted with a C1-C10 hydrocarbon group (R',R").

[0148] Meanwhile, specific examples of metallocene compounds represented by chemical formula 3 include compounds represented by the following structural formula, but the present invention is not limited thereto.

[0149]

[0150] Metallocene compounds represented by chemical formula 3 can be prepared according to known methods used to prepare organic compounds or transition metal compounds.

[0151] In one embodiment of the invention, the metallocene catalyst used may be a hybrid supported catalyst, wherein at least one first metallocene compound represented by chemical formula 1 and at least one second metallocene compound selected from compounds represented by chemical formula 3 are supported together with a cocatalyst compound on a support.

[0152] In a hybrid supported metallocene catalyst according to one embodiment of the present invention, the cocatalyst supported on the support for activating the metallocene compound is an organometallic compound containing a Group 13 metal, and there are no particular limitations, as long as it can be used in the polymerization of olefins in the presence of a conventional metallocene catalyst.

[0153] Specifically, the cocatalyst compound may include at least one of an aluminum-containing first cocatalyst of Formula 4 and a borate-based second cocatalyst of Formula 5.

[0154] [Chemical Formula 4]

[0155] -[Al(R 39 )-O-] k -

[0156] In chemical formula 4, R 39 Each is an independent C1-C20 hydrocarbon group that is halogenated, halogenated, or unsubstituted, and k is an integer greater than 2.

[0157] [Chemical Formula 5]

[0158] T + [BG4] -

[0159] In chemical formula 5, T + It is a polyatomic ion with a +1 valence, B is boron in a +3 oxidation state, and each G is independently selected from hydrogen, dialkylamide, halide, alkoxy, aryloxy, hydrocarbon, halogenated carbonyl and halogen-substituted hydrocarbon, wherein G has 20 or fewer carbon atoms, provided that G is halide in one or more positions.

[0160] By using the first and second cocatalysts as described above, the polyethylene finally prepared can have a more uniform molecular weight distribution, while also enhancing polymerization activity.

[0161] The first cocatalyst of Formula 4 can be a compound based on alkylaluminoxanes, wherein the repeating units are arranged in a linear, cyclic, or network form. Specific examples of the first cocatalyst include methylaluminoxane (MAO), ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc.

[0162] Furthermore, the second cocatalyst of Formula 5 can be a trisubstituted ammonium salt, a dialkylammonium salt, or a trisubstituted phosphonium salt-type borate compound. Specific examples of the second cocatalyst include borate-based compounds in the form of trisubstituted ammonium salts, such as trimethylammonium tetraphenylborate, methyl bis(octadecylammonium) tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, methyl tetradecyloctadecylammonium tetraphenylborate, N,N-dimethylphenylammonium tetraphenylborate, N,N-diethylphenylammonium tetraphenylborate, N,N-dimethyl(2,4,6-trimethylphenylammonium)tetraphenylborate, and trimethylammonium tetra(pentafluorophenyl) ) borates, methyl ditetradecylammonium tetra(pentafluorophenyl)borate, methyl dioctadecylammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, N,N-diethylphenylammonium tetra(pentafluorophenyl)borate, N,N-dimethyl(2,4,6-trimethylphenylammonium)tetra(pentafluorophenyl)borate, trimethylammonium tetra (2,3,4,6-Tetrafluorophenyl)borate, triethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, tri(n-butyl)ammonium tetra(2,3,4,6-tetrafluorophenyl)borate, dimethyl(tert-butyl)ammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-diethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, or N,N-dimethyl-( 2,4,6-Trimethylphenylamine)tetra(2,3,4,6-tetrafluorophenyl)borate, etc.; borate-based compounds in the form of dialkylammonium salts, such as bis(octadecylammonium)tetra(pentafluorophenyl)borate, bis(tetradecylammonium)tetra(pentafluorophenyl)borate, or dicyclohexylammonium)tetra(pentafluorophenyl)borate, etc.; or borate-based compounds in the form of trisubstituted phosphonium salts, such as triphenylphosphonium tetra(pentafluorophenyl)borate, methylbis(octadecylammonium)tetra(pentafluorophenyl)borate, or tri(2,6-dimethylphenyl)phosphonium tetra(pentafluorophenyl)borate.

[0163] In a hybrid supported metallocene catalyst according to one embodiment of the present invention, the mass ratio of all transition metals contained in the first metallocene compound represented by Formula 1 or the second metallocene compound represented by Formula 3 to the support can be from 1:10 to 1:1000. When the support and metallocene compound are contained within the above-mentioned mass ratio range, an optimal configuration is exhibited. Furthermore, the mass ratio of the co-catalyst compound to the support can be from 1:1 to 1:100.

[0164] In a supported metallocene catalyst according to one embodiment of the present invention, a support containing hydroxyl groups on its surface can be used as the support, and preferably, a support having highly reactive hydroxyl and siloxane groups whose surface has been dried to remove moisture can be used.

[0165] For example, silicon dioxide, silicon dioxide-alumina, silicon dioxide-magnesium oxide, etc., which are dried at high temperatures, can be used. They typically contain oxides, carbonates, sulfates, and nitrates, such as Na2O, K2CO3, BaSO4, and Mg(NO3)2.

[0166] The drying temperature of the support is preferably 200 to 800°C, more preferably 300 to 600°C, and most preferably 300 to 400°C. If the drying temperature of the support is below 200°C, it retains excessive moisture, causing the surface moisture to react with the cocatalyst. If the drying temperature is above 800°C, the pores on the support surface bind together to reduce the surface area, and a large number of hydroxyl groups are lost on the surface, leaving only siloxane groups. Therefore, this is undesirable due to the reduction in reaction sites with the cocatalyst.

[0167] The amount of hydroxyl groups on the carrier surface is preferably 0.1 to 10 mmol / g, and more preferably 0.5 to 5 mmol / g. The amount of hydroxyl groups on the carrier surface can be controlled according to the preparation method and conditions of the carrier, or the drying conditions (such as temperature, time, vacuum degree, spray drying, etc.).

[0168] If the amount of hydroxyl groups is less than 0.1 mmol / g, the number of reaction sites with the co-catalyst is reduced. If the amount of hydroxyl groups exceeds 10 mmol / g, it is not preferred because, in addition to the hydroxyl groups present on the surface of the support particles, they may be caused by moisture.

[0169] Meanwhile, according to one embodiment of the present invention, polyethylene can be prepared by polymerizing ethylene in the presence of the above-described hybrid supported metallocene catalyst.

[0170] Ethylene can be polymerized using a continuous slurry polymerization reactor, a circulating slurry reactor, a gas phase reactor, or a solution reactor.

[0171] In this case, according to one embodiment of the invention, polymerization can be carried out by supplying ethylene in a single reactor that optionally contains a molecular weight regulator.

[0172] Alternatively, according to one embodiment of the present invention, polymerization can be carried out by supplying ethylene monomers in the presence of hydrogen.

[0173] At this point, hydrogen plays a role in suppressing the vigorous reaction of the metallocene catalyst in the initial stage of polymerization, thereby enabling the large-scale production of high molecular weight polyolefins. Therefore, by adjusting the use and amount of hydrogen, polyethylene according to one embodiment of the present invention can be effectively obtained.

[0174] Based on the weight of the ethylene monomer, hydrogen can be introduced in amounts ranging from 0.01% to 1% by weight. When the amount of hydrogen used is too small, sufficient catalytic activity cannot be achieved, making it difficult to produce polyethylene with the desired physical properties. When too much hydrogen is introduced, the catalyst activity may also be insufficient.

[0175] Simultaneously, organoaluminum compounds are further introduced into the reactor to remove moisture, and the polymerization reaction can proceed in their presence. Specific examples of these organoaluminum compounds include trialkylaluminum, dialkylaluminum halides, alkyl dihalides, dialkylaluminum hydrides, alkylaluminum sesquihalides, etc., and more specific examples include Al(C2H5)3, Al(C2H5)2H, Al(C3H7)3, Al(C3H7)2H, Al(i-C4H9)2H, Al(C8H5)2H, etc. 17 3. Al(C) 12 H 25 3. Al(C2H5)(C 12 H 25 )2、Al(i-C4H9)(C 12 H 25 2. Al(i-C4H9)2H, Al(i-C4H9)3, (C2H5)2AlCl, (i-C3H9)2AlCl, (C2H5)3Al2Cl3, etc. These organoaluminum compounds can be continuously introduced into the reactor, and can be introduced at a ratio of about 0.1 to 10 moles per kg of reaction medium introduced into the reactor, to appropriately remove moisture.

[0176] The polymerization temperature can be from about 25 to about 500°C, or from about 25 to about 200°C, or from about 50 to about 150°C. Furthermore, the polymerization pressure can be from about 1 to about 100 kgf / cm². 2 Preferably about 1 to about 50 kgf / cm 2 More preferably about 5 to about 30 kgf / cm 2 .

[0177] Supported metallocene catalysts can be used after being dissolved or diluted in aliphatic hydrocarbon solvents having 5 to 12 carbon atoms, such as pentane, hexane, heptane, nonane, decane and their isomers; aromatic hydrocarbon solvents, such as toluene and benzene; or hydrocarbon solvents with chlorine atoms substituted, such as dichloromethane and chlorobenzene. Preferably, the solvent is used after treatment with a small amount of alkylaluminum to remove trace amounts of water, air, etc., which act as catalyst poisons. Additional co-catalysts can also be used.

[0178] Polyethylene according to one embodiment of the invention is prepared by polymerizing ethylene monomers using catalysts of chemical formulas 3 to 5 that primarily polymerize low molecular weight polymer chains and catalysts of chemical formula 1 that primarily polymerize high molecular weight polymer chains.

[0179] Furthermore, since polyethylene with desired physical properties can be produced by adjusting the types and contents of the first and second metallocene compounds, the amount of hydrogen introduced, the content of the comonomer, and the presence or absence of a molecular weight regulator, various modifications can be made. Specifically, the first and second metallocene compounds exhibit different reactivity to hydrogen and the molecular weight regulator. Therefore, polyethylene with the aforementioned physical properties can be prepared based on the selective combination of metallocene compounds in the reactor, the amount of hydrogen introduced, and the presence or absence of a molecular weight regulator.

[0180] The polyethylene produced in this way has a wide melt flow index and melt flow ratio, resulting in excellent processability. Simultaneously, it exhibits low entanglement molecular weight and high resistance to environmental stress cracking. Therefore, it is ideally suited for food containers, bottle caps, and other applications requiring stability under high pressure and high temperature environments.

[0181] Meanwhile, in another embodiment of the present invention, the method for evaluating the injection physical properties of plastic resin includes the following steps:

[0182] Measure the melt index (MI) value of the plastic resin sample;

[0183] Measure the steady-state flow viscosity of the plastic resin sample; and

[0184] Based on the viscosity model equation, the shear thinning index value can be derived from the steady-state flow viscosity value; and

[0185] Injection pressure is predicted using melt index and shear thinning index values.

[0186] The inventors discovered that, after assuming that the injection pressure is related to the rheological properties of the corresponding plastic resin in the injection molding process, the actual injection suitability can be accurately determined by using specific factors that can be measured using a sample of the plastic resin, thus completing the present invention.

[0187] According to one embodiment of the invention, it is desirable to use the value measured according to ASTM D1238 condition E at a temperature of about 190°C and a load of about 2.16 kg as the melt index value.

[0188] The steady-state flow viscosity can preferably be measured as a function that varies with the shear rate increasing or decreasing in the range of about 0.05 to about 500 rad / s. More specifically, it is desirable to measure the steady-state flow viscosity in the region where the steady-state flow viscosity decreases with increasing shear rate, i.e., in the region of shear-thinning behavior, which is a non-Newtonian behavior that does not obey Newton's law of viscosity.

[0189] According to another embodiment of the invention, in the step of deriving the shear thinning index value from the steady-state flow viscosity value according to the viscosity model equation, the shear thinning index value can preferably be obtained by plotting the shear rate value against the steady-state flow viscosity value according to any one or more viscosity model equations of the power law model, the Cross model, the Carreau model, and the Carreau-Yasuda model.

[0190] For example, the power-law model can be represented by the following Equation 1, which is a model used to explain the non-Newtonian behavior of viscous fluids.

[0191] [Equation 1]

[0192] η(γ)=kγ n-1

[0193] In equation 1,

[0194] γ is the shear rate value used to measure steady-state flow viscosity.

[0195] η(γ) is the steady-state flow viscosity, which is expressed as a function of the shear rate.

[0196] K is the viscosity index, and

[0197] n represents the shear thinning index value obtained through measurement.

[0198] The viscosity index (k) is a value that varies depending on the rheological properties of a material in shear flow.

[0199] That is, when using a power-law model, the viscosity index and shear thinning index values ​​in the above equations can be obtained by measuring the shear rate value against the steady-state flow viscosity value in the above equations, and then substituting the measured values ​​into the function represented by Equation 1. The shear thinning index value is used to predict the injection pressure.

[0200] As another example, the Cross model can be represented by the following Equation 2, which is a model used to explain the non-Newtonian behavior of viscous fluids.

[0201] [Equation 2]

[0202] η(γ)=η o / {1+(λγ) 1-n}

[0203] In equation 2,

[0204] γ is the shear rate value used to measure steady-state flow viscosity.

[0205] η(γ) is the steady-state flow viscosity, which is expressed as a function of the shear rate.

[0206] η o This is the viscosity value at zero shear rate, i.e., the zero-shear viscosity value.

[0207] λ is the relaxation time value, and

[0208] n represents the shear thinning index value to be obtained.

[0209] The relaxation time (λ) is a value that varies depending on the rheological properties of the material in shear flow.

[0210] That is, when using the Cross model, the relaxation time and shear thinning index values ​​in the above equations can be obtained by measuring the shear rate value against the steady-state flow viscosity value in the above equations, and then substituting the measured values ​​into the function represented by Equation 2. The shear thinning index value is used to predict the injection pressure.

[0211] As another example, the Carreau model, which is a model used to explain the non-Newtonian behavior of viscous fluids, can be represented by the following Equation 3.

[0212] [Equation 3]

[0213] η(γ)=η o / [{1+(λγ) 2} (1-n) / 2}

[0214] In equation 3,

[0215] γ is the shear rate value used to measure steady-state flow viscosity.

[0216] η(γ) is the steady-state flow viscosity, which is expressed as a function of the shear rate.

[0217] η o This is the viscosity value at zero shear rate, i.e., the zero-shear viscosity value.

[0218] λ is the relaxation time value, and

[0219] n represents the shear thinning index value to be obtained.

[0220] That is, when using the Carreau model, the relaxation time and shear thinning index values ​​in the above equations can be obtained by measuring the steady-state flow viscosity versus the shear rate value in the above equations, and then substituting the measured values ​​into the function represented by Equation 3. The shear thinning index value is used to predict the injection pressure.

[0221] Furthermore, the Carreau-Yasuda model, which is a model used to explain the non-Newtonian behavior of viscous fluids, can be represented by the following Equation 4.

[0222] [Equation 4]

[0223] η(γ)=η o / [{1+(λγ) a} (1-n) / a}

[0224] In equation 4,

[0225] γ is the shear rate value used to measure steady-state flow viscosity.

[0226] η(γ) is the steady-state flow viscosity, which is expressed as a function of the shear rate.

[0227] η o This is the viscosity value at zero shear rate, i.e., the zero-shear viscosity value.

[0228] λ is the relaxation time value.

[0229] a is a material constant, and

[0230] n represents the shear thinning index value to be obtained.

[0231] That is, when using the Carreau-Yasuda model, the relaxation time and shear thinning index values ​​in the above equations can be obtained by measuring the shear rate value against the steady-state flow viscosity value in the above equations, and then substituting the measured values ​​into the function represented by Equation 4. The shear thinning index value is used to predict the injection pressure.

[0232] The model equations represented by Equations 1 to 4 can be appropriately selected based on the rheological properties and shear thinning behavior of the plastic resin. In particular, when the plastic resin to be measured is polyethylene, the Carreau model can be expected to obtain an accurate prediction of the injection pressure.

[0233] The steps for predicting injection pressure using the shear thinning index and flow index derived from the viscosity model equation can be performed using the following mathematical formula 1.

[0234] [Mathematical Expression 1]

[0235] Predicted injection pressure = a(MI) 2.16 ) b *(STI) c

[0236] In mathematical formula 1,

[0237] MI 2.16 It is the melt index value measured according to ASTM D1238 condition E.

[0238] STI is the shear thinning index value derived from the viscosity model equation.

[0239] a can have values ​​from approximately 2200 to approximately 2500.

[0240] b can have values ​​from approximately -0.1 to approximately -0.5, and

[0241] c can have values ​​from about 0.1 to about 0.5.

[0242] That is, after substituting the melt index and shear thinning index values ​​into mathematical formula 1, and introducing the values ​​of a, b, and c based on the rheological properties and shear thinning characteristics of the plastic resin, the injection pressure can be predicted based on a simple calculation formula.

[0243] More specifically, by measuring the actual injection pressure values ​​of some plastic samples, measuring the aforementioned MI and STI values, and then substituting them into the function represented by the aforementioned mathematical formula 1 to obtain the values ​​of a, b, and c, the constant values ​​of mathematical formula 1 can be obtained and used as a reference. In particular, in the case of the aforementioned mathematical formula 1, taking the logarithm of both sides of the function results in a linear system of equations with three unknowns. Therefore, even by taking only at least three plastic resin samples whose injection pressures are to be predicted and performing measurements and calculations, accurate coefficient values ​​can be obtained, and these values ​​can be used as reference values ​​a, b, and c for different plastic resins.

[0244] In the case of polyethylene resin, in Formula 1, a can have a value of about 2200 to about 2500, preferably about 2250 to about 2350, b can have a value of about -0.1 to about -0.5, preferably about -0.2 to about -0.3, or about -0.2 to about -0.25, and c can have a value of about 0.1 to about 0.5, preferably about 0.35 to about 0.45, or about 0.4 to about 0.45.

[0245] However, the present invention is not limited to the range of a, b and c mentioned above, and each coefficient can be determined differently depending on the rheological properties of the plastic resin to be measured.

[0246] The method for evaluating injection physical properties according to one embodiment of the present invention, as described above, can be applied to various plastic polymer resins produced in the form of injection-molded products.

[0247] As an example, the method can be used with plastic resins in which the melt flow index (MI) value is from about 0.1 to about 1.5 g / 10 min, preferably from about 0.2 to about 1.1 g / 10 min.

[0248] According to another embodiment of the invention, the method can be used with plastic resins having a shear thinning index value of about 0.1 to about 0.5, preferably about 0.2 to about 0.45.

[0249] Furthermore, this method can be applied to plastic resins in which the predicted injection pressure value is about 1000 to about 2000 Pa, preferably about 1300 to about 2000 Pa, or about 1350 to about 1850 Pa. The injection pressure can be the injection pressure at about 235°C and an injection speed of about 50 mm / s.

[0250] Furthermore, this method can be used where the density value, measured according to ASTM 1505, is from approximately 0.94 to approximately 0.96 g / cm³. 3 Preferably, it is about 0.950 to about 0.955 g / cm³. 3 Plastic resin.

[0251] Furthermore, this method can be used for plastic resins with a number average molecular weight of about 30,000 g / mol or less, preferably about 10,000 to about 20,000 g / mol or about 12,000 to about 18,500 g / mol.

[0252] Specifically, it can be used with various plastic resins processed into products by injection molding, such as polystyrene-based resins, polyolefin-based resins, polyvinyl chloride-based resins, poly(meth)acrylic acid-based resins, polyamide-based resins, ABS-based resins, urethane epoxy-based resins, urethane acrylic acid-based resins, amino resins, phenolic resins, and polyester-based resins. However, when applied to thermoplastic resins, it may exhibit more precise evaluation results. Among these, it is preferably used with polyolefin-based resins, such as polyethylene and polypropylene resins. Polyethylene resin is the most preferred application.

[0253] The following describes preferred embodiments to aid in understanding the invention. However, these embodiments are provided only for a better understanding of the invention and are not intended to limit the scope of the invention.

[0254] <Examples of Preparation of Metallocene Compounds and Supported Catalysts>

[0255] Synthesis Example 1: Synthesis of a First Metallocene Compound

[0256] 1-1. Preparation of ligand compounds.

[0257] 2.331 g (10 mmol) of indene-indole was added to a dry 250 mL Schlenk flask, and 40 mL of diethyl ether was injected under argon atmosphere. The ether solution was cooled to 0 °C, and then 4.8 mL (12 mmol) of a 2.5 M nBuLi hexane solution was slowly added dropwise. The reaction mixture was slowly heated to room temperature and then stirred until the next day. In another 250 mL Schlenk flask, 20 mL of diethyl ether was added, and then 3.6 mL (30 mmol) of dichloromethyl (tert-butoxyhexyl)silane was injected. The flask was cooled to -78 °C, and a lithiumized solution of indene-indole was injected into it through a sleeve. After injection, the mixture was slowly heated to room temperature and then stirred for about 5 hours, and then stirred for one day. The organic layer was then separated by quenching the flask with 50 mL of water and dried with MgSO4. The ether used as a solvent was removed under reduced pressure. NMR confirmed the presence of 10-((6-(tert-butoxy)hexyl)chloro(methyl)silyl)-5,8-dimethyl-5,10-dihydroindo[1,2-b]indole with a purity of over 95%.

[0258] After confirming the synthesis of the indenoid moiety, 1.7 g (10 mmol) of ((1H-inden-3-yl)methyl)trimethylsilane was added to a dry 100 mL Schlenk flask and dissolved in 40 mL of diethyl ether. Then, 4.8 mL (12 mmol) of a 2.5 M n-butyllithium hexane solution was slowly added dropwise at -78 °C with stirring for 1 day. The previously synthesized 10-((6-(tert-butoxy)hexyl)chloro(methyl)silyl)-5,8-dimethyl-5,10-dihydroindenoid[1,2-b]indole was dissolved in 40 mL of diethyl ether, and then a lithiumized solution of ((1H-inden-3-yl)methyl)trimethylsilane was added dropwise at -78 °C. After approximately 20 hours, the organic layer was separated by adding 50 mL of water to quench the flask and dried with MgSO4. The mixture obtained by filtration was subjected to vacuum-depressurization to evaporate the solvent. As a result, 6.5 g (10.2 mmol, 100%) of 10-((6-(tert-butoxy)hexyl)(methyl)(3-((trimethylsilyl)methyl)-1H-indene-1-yl)silyl)-5,8-dimethyl-5,10-dihydroindene[1,2-b]indole was obtained as a yellow oil.

[0259] Mw: 634.05, Purity (wt%) = 100%

[0260] 1 H NMR(500MHz, CDCl3):-0.40,-0.37(3H,d),0.017(9H,m),1.10(4H,m),1.18(9H,s),1.34(6H,m),2.41(3H,m),3.25(2H,m) ,3.25(1H,m),3.53(1H,m),4.09(3H,s),5.62,5.82,5.95,5.95,6.11(1H,s),7.04~7.32(9H,m),7.54(1H,m),7.75(1H,m).

[0261] 1.2 Preparation of metallocene compounds

[0262] The ligand was added to a 250 mL Schlenk flask dried in an oven, then dissolved in diethyl ether. 2.1 equivalents of nBuLi solution were added, and lithiation continued until the next day. One equivalent of ZrCl4(THF)2 was taken in a glove box and placed in a 250 mL Schlenk flask to prepare a suspension containing diethyl ether or toluene. Both flasks were cooled to -78 °C, and the ligand anion was slowly added to the Zr suspension. After the addition was complete, the reaction mixture was gradually heated to room temperature. When metallization was successfully achieved during this process, the characteristic purple color of the catalyst precursor was confirmed. After stirring for one day, toluene or ether was removed from the mixture to approximately 1 / 5 of its volume under vacuum and reduced pressure, and hexane was added at 5 times the volume of the remaining solvent. The addition of hexane at this point was to promote crystallization, as the synthesized catalyst precursor has low solubility in hexane. The hexane slurry was filtered under argon atmosphere, and the filtered solid and filtrate were evaporated under vacuum and reduced pressure. The remaining filter cake was weighed and sampled in a glove box to confirm the synthesis, yield, and purity. Using diethyl ether as the metallization solvent, 6.08 g (76.5%) of a purple solid was obtained from 6.4 g (10 mmol) of ligand.

[0263] NMR standard purity (wt%) = 100%, Mw = 794.17

[0264] 1 H NMR(500MHz, CDCl3):-0.23,-0.16(9H,d),0.81(3H,m),1.17(9H,m),1.20~ 1.24(3H,m),1.31(2H,s),1.62~1.74(5H,m),1.99~2.11(2H,m),2.55(3H,d ),3.33(2H,m),3.95,4.13(3H,s),5.17,5.21,5.32(1H,s),6.89~7.07(3H, m),7.12~7.21(3H,m),7.29(1H,m),7.36(1H,m),7.44(1H,m),7.84(1H,m).

[0265] Synthesis Example 2: Synthesis of Second Metallocene Compounds

[0266] 2-1. Preparation of ligand compounds

[0267] 10.8 g (100 mmol) of chlorobutanol was added to a dry 250 mL Schlenk flask, followed by the addition of 10 g of molecular sieve and 100 mL of MTBE, and then 20 g of sulfuric acid was slowly added over 30 minutes. The reaction mixture slowly turned pink over time. After 16 hours, it was poured into a saturated sodium bicarbonate solution cooled in an ice bath. Diethyl ether (100 mL × 4) was added to the mixture and the mixture was extracted several times. The collected organic layer was dried over MgSO4. After filtration, the solvent was removed under vacuum and reduced pressure. This yielded 10 g of 1-(tert-butoxy)-4-chlorobutane in the form of a yellow liquid (yield: 60%).

[0268] 1 H NMR (500MHz, CDCl3): 1.16(9H,s),1.67~1.76(2H,m),1.86~1.90(2H,m),1.94(1H,m),3.36(2H,m),3.44(1H,m),3.57(3H,m)

[0269] 4.5 g (25 mmol) of the synthesized 1-(tert-butoxy)-4-chlorobutane was added to a dry 250 mL Schlenk flask and dissolved in 40 mL of THF. 20 mL of sodium cyclopentadienide THF solution was slowly added, and the mixture was stirred for one day. 50 mL of water was added to the reaction mixture, quenched, and extracted with diethyl ether (50 mL × 3). The collected organic layer was then thoroughly washed with brine. The residual water was dried over MgSO4, filtered, and the solvent was removed under vacuum and reduced pressure. Thus, 2-(4-(tert-butoxy)butyl)cyclopentadiene in a dark brown, viscous form was obtained in quantitative yield.

[0270] 1 H NMR(500MHz, CDCl3):1.16(9H,s),1.54~1.60(4H,m),1.65(1H,m),1.82(1H,m),2.37~2.42(2H,m),2.8 7,2.92(2H,s),3.36(2H,m),5.99(0.5H,s),6.17(0.5H,s),6.25(0.5H,s),6.34(0.5H,s),6.42(1H,s)

[0271] 2-2. Preparation of metallocene compounds

[0272] 4.3 g (23 mmol) of the ligand compound synthesized in 1-1 was added to a dry 250 mL Schlenk flask and dissolved in 60 mL of THF. 11 mL of a 2.0 M hexane solution (28 mmol) of n-BuLi was added, and the mixture was stirred for one day. This solution was then slowly added at -78 °C to a flask containing 3.83 g (10.3 mmol) of ZrCl4(THF)2 dispersed in 50 mL of diethyl ether.

[0273] When the reaction mixture was heated to room temperature, the light brown suspension turned into a turbid yellow suspension. After stirring for one day, all solvent in the reaction mixture was dried, and 200 mL of hexane was added. The mixture was sonicated and allowed to settle. The hexane solution floating on the top layer was collected by decanting with a sleeve. The hexane solution obtained by repeating this process twice under vacuum and reduced pressure was dried. Thus, the formation of bis(3-(4-(tert-butoxy)butyl-2,4-dienyl)zirconium chloride (IV) as a light yellow solid was confirmed.

[0274] 1 H NMR (500MHz, CDCl3): 0.84(6H,m),1.14(18H,s),1.55~1.61(8H,m),2.61(4H,m),3.38(4H,m),6.22(3H,s),6.28(3H,s)

[0275] Preparation Example 1: Preparation of Supported Catalyst

[0276] Add 50 mL of toluene solution to a 300 mL glass reactor, then add 10 g of dried silica (SP2410, manufactured by Grace Davison), and stir while raising the reactor temperature to 40 °C. Add 60 mL of a 10 wt% methylaluminoxane (MAO) / toluene solution. After raising the temperature to 60 °C, stir the mixture at 200 rpm for 12 hours. After lowering the reactor temperature to 40 °C, stop stirring and allow sedimentation for 10 minutes, then decant the reaction solution. Add another 100 mL of toluene and stir for 10 minutes. Stop stirring and allow sedimentation for 10 minutes, then decant the toluene solution.

[0277] Add 50 mL of toluene to the reactor, add 0.50 g of the metallocene compound from Synthesis Example 1 as a high molecular weight catalyst precursor and 10 mL of toluene to the reactor, and stir the mixture at 200 rpm for 60 minutes. Add 0.5 g of the metallocene compound from Synthesis Example 2 as a low molecular weight catalyst precursor and 10 mL of toluene to the reactor, and stir the mixture at 200 rpm for 12 hours.

[0278] Subsequently, stirring was stopped and the mixture was allowed to settle for 10 minutes, after which the reaction solution was decanted. 100 mL of hexane was added to the reactor, and the hexane slurry was transferred to a 250 mL Schlenk flask. The hexane solution was then decanted and dried under reduced pressure at room temperature for 3 hours to prepare a hybrid supported metallocene catalyst.

[0279] Preparation of ethylene / α-olefin copolymers

[0280] Example 1

[0281] The supported catalyst prepared in Preparation Example 1 was prepared by quantitatively adding 50 mg of the catalyst in a drying oven, placing it into a 50 mL glass bottle, sealing it with a rubber membrane, and removing it from the drying oven. Polymerization was carried out in a 2 L metal alloy reactor equipped with a mechanical stirrer and capable of temperature control and high pressure operation.

[0282] 1 L of hexane containing 1.0 mmol of triethylaluminum and 1 mL of 1-butene was added to the reactor. The prepared supported catalyst was then added to the reactor without contact with air, and the reactor was incubated at 80 °C at a rate of 9 kgf / cm². 2 Polymerization was carried out for 1 hour while ethylene monomer was continuously supplied under pressure in the presence of hydrogen. At this time, the amount of hydrogen introduced was 0.745 g (0.745 g / h).

[0283] The polymerization was terminated by first stopping stirring, then venting and removing the ethylene gas. Most of the polymerization solvent was removed from the obtained polymer by filtration, and the polymer was dried in a vacuum oven at 80°C for 4 hours.

[0284] Examples 2 to 15

[0285] Except for changing the amount of hydrogen introduced as summarized in Table 1, the polymerization reaction was carried out in the same manner as in Example 1.

[0286] Preparation of a plastic resin sample

[0287] The polyethylene resin of each embodiment was dried overnight in a vacuum oven at 40°C and prepared in pellet form using a twin-screw extruder (BA-19, manufactured by BAUTECH).

[0288] The granular resin obtained by compression was dried again overnight in a vacuum oven at 40°C, and then the samples were made into a form suitable for the measurement conditions of each physical property using an Xplore5.cc micro injection molding machine.

[0289] Measurement of physical properties of a plastic resin sample

[0290] The basic physical properties of the prepared samples are as follows.

[0291] (Density was measured according to ASTM 1505, and the density of all polyethylene resins used was between 0.950 and 0.953 g / cm³) 3 。 )

[0292] 1) Measurement of number-average molecular weight and low molecular weight content

[0293] Number-average molecular weight and molecular weight distribution were measured simultaneously or continuously using GPC-FTIR. The logarithm of molecular weight (Mw) (log Mw) was used as the x-axis, and the logarithmic molecular weight distribution (dwt / dlog Mw) was used as the y-axis. The percentage (%) of molecules with a molecular weight below 3500 g / mol was calculated.

[0294] 2) Melt Index (MI):

[0295] Measured according to ASTM 1238 at 190°C and a load of 2.16 kg.

[0296] 3) Measurement of actual injection pressure

[0297] The polyethylene granules prepared above were introduced into an injection molding machine (model name: Victory 1500, manufacturer: ENGEL), and the actual injection pressure was measured at 240°C, a pressure of 650 bar, and an injection speed of 78 mm / s.

[0298] The values ​​measured above are summarized in Table 1 below.

[0299] Table 1

[0300]

[0301] 4. Steady-state flow viscosity value

[0302] The steady-state flow viscosity is measured as a function of the change in shear rate at 190°C and 0.5% strain over a range of 0.05 to 500 rad / s.

[0303] 5) Derivation of the shear thinning index

[0304] The shear rate and steady-state viscosity, measured as a function of shear rate versus steady-state viscosity in section 4), are substituted into the Carreau model equation below to obtain the shear thinning index.

[0305] More specifically, i) the Carreau model function value used for the shear rate value under the measurement conditions, ii) converges to the actual measured steady-state flow viscosity value, and iii) determines the value of n in the following equation, which is derived as the shear thinning index value.

[0306] η(γ)=η o / [{1+(λγ) 2} (1-n) / 2}

[0307] 6) Calculation of predicted injection pressure

[0308] Injection pressure is predicted by substituting the melt index and shear thinning index values ​​into the following equation.

[0309] Predicted injection pressure = a(MI) 2.16 ) b *(STI) c

[0310] The values ​​of a, b, and c correspond to those of polyethylene, and are represented by values ​​of 2290.47147, -0.22201, and 0.42278, respectively.

[0311] The values ​​measured above are summarized in Table 2 below.

[0312] Table 2

[0313]

[0314]

[0315] Referring to Table 1, in the case of embodiments of the present invention that are determined to be suitable for injection, it has been found that the injection pressure applied in the actual injection process is all less than 1600 Pa, and if either the number average molecular weight value or the low molecular weight content is not met, it has been found that the actual measured injection pressure exceeds 1600 Pa.

[0316] This clearly explains why the actual injection suitability of polyethylene resin is directly related to the above-mentioned number-average molecular weight value and the content of low molecular weight molecules with a molecular weight value below 3500 g / mol.

[0317] Referring to Table 2, it can be clearly seen that the injection pressure predicted according to the embodiments of the present invention has a value very similar to the actual applied injection pressure.

[0318] Specifically, by comparing the actual injection pressure with the predicted injection pressure value, R can be determined. 2The values ​​show a very high correlation, close to 0.975, which clearly explains the direct correlation between the actual injection pressure of the plastic resin and the aforementioned melt index and shear thinning index values. This is because if the actual injection pressure of the plastic resin were not directly related to the aforementioned melt index (MI) and steady-state flow viscosity values, the predicted injection pressure value would not converge to the actual injection pressure value regardless of how the coefficients in Equation 1 (e.g., a, b, and c) are adjusted.

[0319] However, it has been clearly demonstrated that the actual injection pressure of the plastic resin has a first-order correlation with the injection pressure value predicted by Formula 1. This clearly supports the assertion, as described in this invention, that the actual injection pressure of the plastic resin is directly related to the melt index and shear thinning index values, which are physical properties related to the shear thinning properties of each plastic resin, independent of the determined coefficient values ​​(such as a, b, and c) used in Formula 1.

Claims

1. A method for evaluating the injection physical properties of plastic resins, comprising the following steps: Measure the number-average molecular weight of plastic resin samples; Calculate the portion of low molecular weight molecules with a molecular weight below 3,500 g / mol in the molecular weight distribution of the plastic resin sample. as well as The injection molding suitability of plastic resins can be predicted by the number average molecular weight and the fraction of low molecular weight molecules. The injection suitability of plastic resins is predicted by determining that a plastic resin sample is suitable for injection when its number average molecular weight is below 14,500 g / mol and the fraction of low molecular weight molecules with a molecular weight below 3,500 g / mol is above 4%.

2. The method for evaluating the injection physical properties of plastic resins according to claim 1, wherein, The number average molecular weight of the plastic resin sample is between 10,000 and 14,500 g / mol.

3. The method for evaluating the injection physical properties of plastic resins according to claim 1, wherein, The portion of the low molecular weight molecules having a molecular weight of less than 3,500 g / mol is 4% to 10%.

4. The method for evaluating the injection physical properties of plastic resins according to claim 3, wherein, Under injection molding conditions of 240 °C and 650 bar, the plastic resin has an injection pressure of less than 1600 Pa.

5. The method for evaluating the injection physical properties of plastic resins according to claim 1, wherein, The plastic resin is polyethylene resin.

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