Polyethylene composition and oriented film comprising same

Abstract

The present invention relates to a polyethylene composition and an oriented film comprising same, the polyethylene composition being capable of producing a stretched film having high shrinkage resistance with excellent film stretching processability and productivity.

Description

Polyethylene composition and stretched film containing the same

[0001] The present invention is to provide a polyethylene composition capable of producing a stretched film having high shrinkage resistance with excellent film stretching processability and productivity, and a stretched film comprising the same.

[0002] Thin film products manufactured from linear low-density polyethylene (LLDPE) and / or high-density polyethylene (HDPE) are widely used in packaging applications such as product bags, food bags, food and specialty packaging, and industrial liners. In these applications, packaging films that allow for packaging while maintaining the shape of the product are primarily used, thereby providing protection from touch during product display.

[0003] In particular, among these packaging films, uniaxially oriented or biaxially oriented polymer films are widely used for packaging purposes due to their excellent mechanical properties, productivity, and printability. Commercially available packaging films generally use BOPP (biaxially oriented polypropylene), BOPET (biaxially oriented polyethylene terephthalate), or BOPA (biaxially oriented polyamide) for the printing layer and LLDPE film for the sealing layer. These composite materials are not recyclable, and the demand for single-material packaging is increasing due to the spread of packaging recycling regulations. Therefore, research and development is underway to manufacture single-material packaging films by replacing the printing layer film with uniaxially oriented polyethylene (UPE) or biaxially oriented polyethylene (BOPE) film.

[0004] However, commercial polyethylene (PE) resins lack sufficient stretch stability, and phenomena such as fracture and melting occur during stretching, making it difficult to apply them to biaxial stretching processes. To ensure stretch stability, products in the form of polyethylene compositions containing resins with low density and high melt index are being developed. However, such compositions exhibit low stiffness, high shrinkage, and low heat resistance, making them unsuitable as PE resins for uniaxial or biaxially stretched films.

[0005] In particular, stretched films, which are primarily used as packaging materials, are manufactured into final products through printing and coating processes. High elongation characteristics are required to ensure productivity and excellent film properties, and high heat resistance is required because post-processing steps such as printing and coating are mainly carried out at high temperatures.

[0006] Accordingly, there is a need for a method to provide a PE composition for uniaxial or biaxial stretching that selects a polyethylene resin having a molecular structure favorable for stretching and selects an appropriate composition, thereby exhibiting excellent stretching stability during film processing, while possessing high shrinkage resistance due to excellent heat resistance and exhibiting excellent film processability and productivity.

[0007] The present invention is to provide a polyethylene composition capable of producing a stretched film having high shrinkage resistance with excellent film stretching processability and productivity, and a stretched film comprising the same.

[0008] In one embodiment of the present invention

[0009] When the relative ratio of the peak areas of the crystallization fraction eluted according to temperature (°C) was measured using the crystallization elution fractionation (CEF) analysis method,

[0010] The ratio of the peak area of ​​the low-crystallinity fraction eluted at 70°C or higher and 95°C or lower to the total peak area (CEF ≤95℃≥70℃ ) is 10% or more and 25% or less, and

[0011] The ratio of the peak area of ​​the highly crystalline fraction eluted at 100 ℃ or higher to the total peak area (CEF ≥100℃ ) is 6% or more and 15% or less, and

[0012] The ratio of the peak areas of the above low-crystallinity fraction (CEF) ≤95℃≥70℃ The ratio of the peak area of ​​the highly crystalline fraction (CEF) to the above (CEF) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) is 0.24 or greater, and

[0013] Density is 0.940 g / cm³ 3 Above 0.970 g / cm³ 3 Lee Ha-in,

[0014] A polyethylene composition is provided.

[0015] In addition, in another embodiment of the present invention, a stretched film comprising the polyethylene composition of the above embodiment is provided.

[0016] The polyethylene according to the present invention has the excellent effect of being able to manufacture a stretched film having high shrinkage resistance and excellent printability, along with excellent mechanical properties and stretch stability, and decent film processability and productivity.

[0017] Figure 1 shows a graph of crystallization elution fraction (CEF) measured for the polyethylene compositions of Example 1 and Comparative Example 1 according to one embodiment of the present invention.

[0018] FIG. 2 is a crystallization elution fraction (CEF) graph measured for polyethylene compositions of Examples 1 to 5 and Comparative Examples 1 to 10 according to one embodiment of the present invention, showing the ratio of the peak area in the region where the temperature is 100°C or higher, specifically 100°C or higher and 105°C or lower, with the total peak area set to 100%. ≥100℃ ) and the low-crystallinity content (CEF) representing the ratio of the crystal fraction peak area eluted at 70 ℃ or higher and 95 ℃ or lower. ≤95℃≥70℃This is a distribution graph showing the correlation between ) with the y-axis and x-axis, respectively.

[0019] This document may use ordinal numbers such as "first" and "second" when referring to multiple components, but there is no priority among these components.

[0020] In this document, if a specific commercially available product is used as an ingredient, the characteristics of that ingredient may refer to the characteristics listed in the product's Technical Data Sheet (TDS) or Certification of Analysis (COA).

[0021] In this document, if the physical properties of a specific material vary depending on temperature and pressure, the measurement criteria for those physical properties may be 25 ℃ and 101.325 kPa.

[0022] In this document, the numerical range "within the range of A to B" means "greater than or equal to A and less than or equal to B." The numerical values ​​mentioned in this document are rounded values. For example, 1.5 is a number within the range of 1.45 to 1.54.

[0023] The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention.

[0024] A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0025] In this specification, terms such as “comprising,” “comprising,” or “having” are used to describe features, numbers, steps, components, or combinations thereof that are implemented, and do not exclude one or more other features, numbers, steps, components, combinations thereof, or the possibility of addition.

[0026] Additionally, terms such as "approximately" and "substantially" used throughout this specification are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention.

[0027] In addition, in the present invention, the term (co)polymer includes both homopolymers and copolymers.

[0028] Unless otherwise defined in this specification, "copolymer" may mean block copolymer, random copolymer, graft copolymer, or alternating copolymer, and "copolymer" may mean block copolymer, random copolymer, graft copolymer, or alternating copolymer.

[0029] For reference, in this specification, "part by weight" refers to a relative concept in which the weight of one substance is expressed as a ratio to the weight of another substance. For example, in a mixture containing 50 g of substance A, 20 g of substance B, and 30 g of substance C, the amounts of substance B and substance C are 40 parts by weight and 60 parts by weight, respectively, based on 100 parts by weight of substance A.

[0030] Meanwhile, "weight % (% by weight)" refers to an absolute concept in which the weight of a substance is expressed as a percentage of the total weight. In the mixture given as an example above, the content of substance A, substance B, and substance C is 50 weight%, 20 weight%, and 30 weight%, respectively, out of 100% of the total weight of the mixture.

[0031] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0032] The present invention will be described in detail below.

[0033] (Polyethylene composition)

[0034] According to one aspect of the present invention, when the relative ratio of the peak areas of crystallized fractions eluted according to temperature (°C) is measured using a crystallization elution fractionation (CEF) analysis method, the ratio of the peak area of ​​the low-crystallinity fraction eluted at 70°C or higher and 95°C or lower to the total peak area (CEF ≤95℃≥70℃ ) is 10% or more and 25% or less, and the ratio of the peak area of ​​the highly crystalline fraction eluted at 100 ℃ or higher to the total peak area (CEF ≥100℃ A polyethylene composition is provided in which ) is 6% or more and 15% or less.

[0035] A polyethylene composition according to one embodiment of the present invention has the characteristics suitable for manufacturing a stretched film having high shrinkage resistance, while maintaining productivity and stretch stability equivalent to or better than existing ones, by optimizing a unimodal or bimodal slurry polymerization process in the presence of a Ziegler-Natta catalyst or a metallocene catalyst to control the balance between heat resistance and stretchability.

[0036] In particular, the polyethylene composition according to one embodiment of the present invention can produce a uniaxial or biaxially stretched film that exhibits excellent stretch stability during film processing, high shrinkage resistance due to excellent heat resistance, and excellent film processability and productivity by optimizing the distribution of crystal fractions in the molecular structure to a predetermined range.

[0037] Preferably, the polyethylene composition may include one or more ethylene-alpha-olefin copolymers. More preferably, the polyethylene composition may include two ethylene-alpha-olefin copolymers.

[0038] A polyethylene composition according to one embodiment of the present invention is characterized by optimizing the distribution of both low-crystallinity fractions and high-crystallinity fractions that are eluted at a specific temperature in the molecular structure, so as to enable the production of a stretched film having excellent stretchability and heat resistance.

[0039] This polyethylene composition can simultaneously control the ratio of low-crystal fractions leached at 70°C or higher and the ratio of high-crystal fractions leached at 100°C or higher to an optimal range, thereby having high elongation characteristics to ensure productivity and excellent film properties during film processing, while also having excellent film strength and shrinkage resistance to withstand high-temperature treatment in post-processing such as printing and coating.

[0040] Specifically, the polyethylene composition is, when the relative ratio of the crystallization fraction peak area eluted according to temperature (°C) is measured using the crystallization elution fractionation (CEF) analysis method, the ratio of the crystallization fraction peak area eluted at 70°C or higher and 95°C or lower to the total peak area (CEF ≤95℃≥70℃ ), that is, the ratio of the peak areas of the low-crystallinity fraction (CEF ≤95℃≥70℃ The (low crystal content) may be 10% or more and 25% or less. In this crystallization elution fractionation (CEF) analysis method, the ratio of the peak areas of the crystal fraction eluting at 70°C or more and 95°C or less (CEF ≤95℃≥70℃In other words, the low-crystal content must be at least 10% to ensure that the film can be stretched to high magnifications without breaking. Generally, film stretching proceeds in a semi-solid state, and relatively low-crystal components exist mostly in a molten state during this process, contributing to high stretchability and uniform stretching. Therefore, the higher the low-crystal content, the better the stretchability can be. However, if this low-crystal content exceeds 25%, the film becomes too flimsy, leading to sagging, reduced uniformity, and in severe cases, even breakage. Furthermore, the orientation is reduced, making it highly likely to exhibit characteristics similar to a drawing film. Additionally, because movement is relatively easier compared to high-crystal content and movement is possible at lower temperatures, there is a high possibility that the shrinkage rate of the final film will increase.

[0041] The ratio of the peak areas of the above low-crystallinity fraction (CEF) ≤95℃≥70℃ ) may be 10% or more, 10.5% or more, 11% or more, 11.5% or more, 12% or more, 12.5% ​​or more, 13% or more, 13.5% or more, 14% or more, 14.5% or more, 15% or more, 15.5% or more, 16% or more, 16.5% or more, 17% or more, 17.5% or more, or 18% or more, and may be 25% or less, 24.8% or less, 24.5% or less, 24.3% or less, 24% or less, 23.8% or less, 23.5% or less, 23.3% or less, 23% or less, 22.8% or less, 22.5% or less, 22.3% or less, 22% or less, 21.8% or less, 21.5% or less, or 21% or less. There is. The ratio of the peak areas of the above low-crystallinity fraction (CEF) ≤95℃≥70℃ ) may be within the range of any one lower limit selected from the lower limits listed above and any one upper limit among the upper limits listed above. The ratio of the low-crystallinity fraction peak area (CEF) ≤95℃≥70℃) may preferably be 12% or more and 24% or less, more preferably 13% or more and 23% or less, and even more preferably 14% or more and 22% or less. Thus, the low crystal content (CEF) eluted at 70°C or more and 95°C or less. ≤95℃≥70℃ By optimizing the ratio, it is possible to secure productivity and excellent film properties with high elongation during film processing, as well as increase film strength and simultaneously improve shrinkage resistance with excellent heat resistance.

[0042] In addition, when the relative ratio of the crystallization fraction peak area eluted according to temperature (°C) is measured using the crystallization elution fractionation (CEF) analysis method for the above-mentioned polyethylene composition, the ratio of the crystallization fraction peak area eluted at 100°C or higher to the total peak area (CEF ≥100℃ ), that is, the ratio of the peak area of ​​the highly crystalline fraction (highly crystalline content) may be 6% or more and 15% or less. For example, the above highly crystalline content can be measured by the ratio of the peak area of ​​the crystal fraction eluted at 100°C or higher during CEF analysis, and specifically, the value measured at 100°C or higher and 120°C or lower (CEF ≤120℃≥100℃ ) can be. More specifically, the above high crystal content is the value measured at 100 ℃ or higher and 115 ℃ or lower during CEF analysis (CEF ≤115℃≥100℃ ), or values ​​measured at 100 ℃ or higher and 110 ℃ or lower (CEF ≤110℃≥100℃ ), or values ​​measured between 100 ℃ and 105 ℃ (CEF ≤105℃≥100℃ It can be.

[0043] When measuring the relative ratio of the peak area of ​​the crystal fraction eluted according to temperature (°C) using the crystallization elution fractionation (CEF) analysis method, the highly crystalline portion that elutes at 100°C or higher relative to the total peak area acts like a framework during the stretching process because it has a high elution temperature and is a dense crystal, thereby preventing sagging or breakage of the film and increasing orientation, resulting in superior mechanical properties or shrinkage rate of the film. Accordingly, the content of the highly crystalline portion must be 6% or more. However, if the content of such a highly crystalline portion exceeds 15% and is too high, the high crystallinity results in low fluidity and adverse effects on stretchability, and the stretchability and processability may decrease during film manufacturing.

[0044] The ratio of the peak areas of the above-mentioned high-crystallinity fraction (CEF) ≥100℃ ) may be 6.5% or more, 6.8% or more, 7% or more, 7.3% or more, 7.5% or more, 7.8% or more, 8% or more, 8.3% or more, 8.5% or more, 9% or more, 9.5% or more, and 14.5% or less, 14.3% or less, 14% or less, 13.8% or less, 13.5% or less, 13.3% or less, 13% or less, 12.8% or less, 12.5% ​​or less, 12.3% or less, 12% or less, 11.8% or less, 11.5% or less, 11.3% or less, or 11% or less. The ratio of the peak area of ​​the above-mentioned high-crystal fraction (CEF) ≥100℃ ) may be within the range of any one lower limit selected from the lower limits listed above and any one upper limit among the upper limits listed above. The ratio of the peak areas of the highly crystalline fraction (CEF) ≥100℃ ) may preferably be 6% or more and 15% or less, more preferably 7% or more and 14% or less, and even more preferably 8% or more and 13% or less. The high crystal content (CEF) eluted at 100 ℃ or higher in this way ≥100℃By optimizing the ratio, when the stretched film is manufactured into a final product through printing and coating processes, not only can the film strength be increased and shrinkage resistance improved with excellent heat resistance, but at the same time, productivity and excellent film properties can be secured with high stretchability during film processing.

[0045] Low crystal content (CEF) of the above polyethylene composition ≤95℃≥70℃ ) Ratio and High Crystalline Content (CEF) ≥100℃ The ratio not only satisfies the range described above, but also optimizes the ratio of the two crystal fraction contents described above to produce a stretched film with excellent heat resistance, shrinkage rate, and other post-stretch film qualities, along with stretchability.

[0046] Meanwhile, the ratio of the low-crystallinity fraction peak areas (CEF) ≤95℃≥70℃ The ratio of the peak area of ​​the highly crystalline fraction (CEF) to the above (CEF) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) is the low crystallinity content (CEF ≤95℃≥70℃ High crystal content (CEF) relative to ) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ It can be represented as ).

[0047] Specifically, the ratio of the two crystal fraction contents described above, namely, the low crystal content (CEF ≤95℃≥70℃ High crystal content (CEF) relative to ) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) may be 0.24 or higher, or 0.24 or higher and 1.50 or lower. The above low crystal content (CEF) ≤95℃≥70℃ High crystal content (CEF) relative to ) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃The lower limit of ) may be 0.20, 0.32, 0.44, 0.45, 0.47, 0.48, 0.59, 0.69, or 0.78, and the upper limit may be 1.47, 1.17, 0.87, 0.78, 0.69, 0.59, 0.48, 0.47, or 0.45. The above low crystal content (CEF ≤95℃≥70℃ High crystal content (CEF) relative to ) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) may be within the range of any one lower limit selected from the lower limits listed above and any one upper limit listed above. The low crystal content (CEF) ≤95℃≥70℃ High crystal content (CEF) relative to ) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) can preferably be 0.3 or more and 0.95 or less, more preferably 0.35 or more and 0.93 or less, and even more preferably 0.4 or more and 0.90 or less.

[0048] In addition, the polyethylene composition may exhibit crystallization fraction peaks eluting at temperatures below 70°C and above 95°C but below 100°C, in addition to the aforementioned highly crystalline and low-crystalline fraction peaks. That is, when the relative ratio of the crystallization fraction peak areas eluting according to temperature (°C) is measured using the crystallization elution fractionation (CEF) analysis method, the polyethylene composition [is the ratio of the residual area of ​​the crystallization fraction peaks eluting at temperatures below 70°C and above 95°C but below 100°C to the total peak area (CEF). <70℃,<100℃>95℃ ) is the content of the two crystal fractions mentioned above out of 100% of the total crystal fraction amount, i.e., the low crystal content (CEF ≤95℃≥70℃ ) and high crystallinity content (CEF ≥100℃ It can be the content excluding the sum of ).

[0049] For example, the ratio of residual area (CEF <70℃,<100℃>95℃)(%) may be 68.6 to 76.4, 68.8 to 76, or 69 to 75.2. In addition, the ratio of the residual area (CEF <70℃,<100℃>95℃ )(%), i.e., the content of the remaining crystal fraction (CEF <70℃,<100℃>95℃ The lower limit of )(%) may be 68.6, 69.1, 70.5, 71.8, 72.4, 73.0, 73.5, 74.0, 74.1, 74.1, 74.2, 74.3, or 74.7, and the upper limit may be 76.4, 75.1, 74.7, 74.3, 74.2, 74.1, 74.1, 74.0, 73.5, 73.0, 72.4, 71.8, or 70.5. The ratio of residual area (CEF <70℃,<100℃>95℃ )(%) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0050] In addition, the ratio of the peak areas of the crystal fractions eluted at temperatures below 70 ℃ (CEF <70℃ )(%) may be 5 or less, 0.1 to 5, or 0.2 to 4.9. In addition, the ratio of the peak areas of the crystal fractions eluted at temperatures below 70 ℃ (CEF <70℃ The lower limit of )(%) may be 0.5, 0.8, 1, 1.5, 2, 2.5, or 3, and the upper limit may be 4.8, 4.6, 4.5, 4.35, 4.3, 4.25, 4.2, 4.15, 4.1, 4, 3.8, or 3.5. The ratio of the peak areas of the crystal fractions eluted below 70 ℃ (CEF <70℃ )(%) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0051] In addition, the ratio of the residual area of ​​the crystal fraction peaks eluted at temperatures greater than 95 ℃ and less than 100 ℃ (CEF <100℃>95℃ )(%) may be 77 or less, 56 to 77, or 57 to 76. In addition, the ratio of the residual area of ​​the crystal fraction peaks eluted at temperatures greater than 95 ℃ and less than 100 ℃ (CEF<100℃>95℃ The lower limit of )(%) may be 57, 57.5, 58, 58.5, 59, 59.5, 60, 62, 64, 64.5, or 65, and the upper limit may be 76, 74.5, 74, 73.5, 73, 72.5, 72, 71.5, 71, 70.5, 70, 69.5, 69, or 68.5. The ratio of the residual area of ​​the crystal fraction peaks eluted above 95 ℃ and below 100 ℃ (CEF <100℃>95℃ )(%) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0052] In the present invention, the crystal fraction content of the polyethylene composition described above, i.e., the low crystal content (CEF ≤95℃≥70℃ ), crystallinity content (CEF ≥100℃ ), and the content of the remaining crystal fraction (CEF <70℃,<100℃>95℃ ) is measured by the Crystallization Elution Fractionation (CEF) analysis method.

[0053] For example, the crystal fraction content by Crystallization Elution Fraction (CEF) analysis of a polyethylene composition can be determined using the PolymerChar Agilent Technologies 7890A instrument. For instance, after dissolving a sample at a concentration of 1.5 mg / mL in 20 mL of 1,2,4-trichlorobenzene, 30 ℃ from 150 ℃ Up to 40 ℃ After dissolving while raising the temperature at a rate of / min, 20 ℃ Up to 0.5 ℃ Recrystallize while lowering the temperature at a rate of / min, and again 140 ℃ Up to 1 ℃ The elution amount is measured while raising the temperature at a rate of / min. At this time, the total integrated value (20 to 140) obtained by integrating the dW / dT value with respect to temperature for the weight fraction W obtained according to the elution temperature T ℃By normalizing based on ), the fraction (%) according to temperature can be calculated. For this, the x-axis is the elution temperature (Elution temperature, ℃ It can be represented as a crystallization elution fraction (CEF) graph where the y-axis is Fraction (%). The crystallization elution fraction (CEF) graph obtained in this way indicates the relative ratio of the peak areas of the eluted fractions according to temperature (°C).

[0054] In this CEF graph, with the total peak area set to 100%, the temperature is 100 ℃ The ratio of the peak area of ​​the region to the crystallinity content (CEF) ≥100℃ Indicated as ), the ratio of the peak area in the region between 70 ℃ and 95 ℃ is the low-crystallinity content (CEF ≤95℃≥70℃ It can be expressed as ). Specifically, the method for measuring the crystal fraction content by such crystallization elution fraction (CEF) analysis is as described in Test Example 1 below.

[0055] Meanwhile, a polyethylene composition according to one embodiment of the present invention has a melt index (MI 2.16 The melt index (at 190°C, 2.16 kg load) may be 0.5 to 3.0 g / 10 min, 0.51 to 2.8 g / 10 min, or 0.52 to 2.6 g / 10 min or less. The melt index of the polyethylene resin composition affects film properties such as film processability, strength, heat resistance, and shrinkage rate during the manufacture of a stretched film. MI 2.16 When within the above range, processability is excellent, and heat resistance or shrinkage rate can be improved along with film rigidity.

[0056] In addition, the melt index (MI) of the polyethylene resin composition 2.16, 190 ℃, 2.16 kg load)(g / 10 min) may have a lower limit of 0.45, 0.49, 0.52, 0.60, 0.67, 0.69, 0.70, 0.78, 0.85, 0.88, 0.90, 0.92, 0.93, or 1.01, and an upper limit of 3, 2.9, 2.7, 2.5, 2.3, 2.0, 1.80, 1.50, 1.30, 1.20, 1.10, 1.09, 1.01, 0.93, 0.92, 0.90, 0.88, 0.85, 0.78, 0.70, 0.69, 0.67, or It can be 0.60. The melt index (MI) of the above polyethylene resin composition 2.16 , 190 ℃, 2.16 kg load) (g / 10 min) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0057] In particular, the melt index (MI) of the polyethylene resin composition 2.16 If the melt index (MI, 190°C, 2.16kg load) is too low, the extrusion pressure increases, processability decreases, and it may affect the film appearance, such as melt fracture; furthermore, if it is too low, bubble formation may be difficult or excessive shaking may occur during the blowing process. Accordingly, the melt index (MI) of the polyethylene resin composition 2.16 It is desirable that the above-mentioned range (190 ℃, 2.16 kg load) satisfies the above-mentioned range.

[0058] In the present invention, the melt index (MI) 2.16 ) can be measured at 190°C under a load of 2.16 kg according to the American Society for Testing Materials standard ASTM D 1238 (Condition E, 190°C, 2.16 kg). For example, such a melt index (MI 2.16 The method for measuring ) is as described in Test Example 1 below.

[0059] In addition, the polyethylene composition has a density of 0.940 to 0.970 g / cm³ 3, 0.945 to 0.968 g / cm³ 3 , or 0.947 to 0.965 g / cm³ 3 It may be possible. The density of the polyethylene resin composition affects the stiffness of the stretched film. When the density of the polyethylene resin composition is within the above range, it is possible to prevent the stiffness of the stretched film from decreasing, while at the same time preventing the decrease in the stretchability of the film due to high density.

[0060] Preferably, the density (g / cm³) of the polyethylene resin composition. 3 ) may have a lower limit of 0.941, 0.942, 0.943, 0.944, 0.945, 0.957, 0.958, 0.959, 0.960, or 0.961, and an upper limit of 0.968, 0.965, 0.962, 0.961, 0.960, 0.959, or 0.958. The density (g / cm³) of the polyethylene resin composition. 3 ) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0061] In the present invention, density (g / cm³) 3 ) can be measured according to ISO 1183-2 standards, and, for example, may be a value measured at 23 ℃. For example, such density (g / cm³) 3 The method for measuring ) is as described in Test Example 1 below.

[0062] Meanwhile, the above polyethylene composition may have a weight-average molecular weight (Mw) of 80,000 to 160,000 g / mol, 85,000 to 140,000 g / mol, or 100,000 to 150,000 g / mol. The above polyethylene composition may have a lower limit of weight-average molecular weight (Mw) (g / mol) of 123,000, 123,300, 125,900, 128,500, 128,750, 129,000, 131,000, 133,000, 133,550, 134,100, 136,450, 138,800, 141,750, 144,700, or 145,650, and an upper limit of 153,150, 146,600, 145,650, 144,700, 141,750, 138,800, 136,450, 134,100, 133,550, It may be 133,000, 131,000, 129,000, 128,750, or 128,500, 125,900. The weight-average molecular weight (Mw) (g / mol) of the polyethylene composition may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0063] In addition, the polyethylene composition may have a number average molecular weight (Mn) of 5,000 to 20,000 g / mol, 5,100 to 19,800 g / mol, or 5,200 to 19,500 g / mol. In addition, the polyethylene composition may have a lower limit of number average molecular weight (Mn) (g / mol) of 5200, 5500, 5800, 6000, 6200, 6500, 6800, 7000, 8200, 8500, 8800, 9000, 9200, 9500, 9800, 10000, or 10500, and an upper limit of 19500, 19000, 18500, 18000, 17500, 17000, 16500, 16000, 15500, 15000, 14500, 14000, or 13500. The number average molecular weight (Mn) (g / mol) of the above polyethylene composition may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0064] The molecular weight distribution (PDI, Mw / Mn) of the above polyethylene composition may be 4 or more and 15 or less. In addition, the lower limit of the molecular weight distribution (Mw / Mn) of the polyethylene composition may be 5.11, 5.63, 6.14, 6.29, 6.44, 6.49, 6.53, 6.55, 6.56, 6.84, 7.12, 7.93, 8.73, 9.06, 9.39, 9.52, and the upper limit may be 10.30, 9.98, 9.65, 9.52, 9.39, 9.06, 8.73, 7.93, 7.12, 6.84, 6.56, 6.55, 6.53, 6.49, 6.44, or 6.29. The molecular weight distribution (Mw / Mn) of the above polyethylene composition may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0065] By having a molecular weight distribution (PDI, Mw / Mn) of the above polyethylene composition in a range greater than or equal to the lower limit, the shear thinning phenomenon can be prevented and the problem of reduced processability due to increased viscosity in the high-shear region can be prevented, and by having a range less than or equal to the upper limit, processability and quality uniformity can be ensured.

[0066] For example, the polyethylene composition exhibits a unimodal or bimodal molecular weight distribution. Here, a unimodal molecular weight distribution refers to a distribution in which most polymer chains have similar molecular weights and a single peak appears on a gel permeation chromatography (GPC) graph. Such a unimodal molecular weight distribution indicates that the polymer chains are relatively uniform and possess consistent characteristics such as strength, durability, and processability. In this case, consistent molecular interactions between polymer chains can be ensured, thereby improving mechanical properties such as tensile strength. Furthermore, a bimodal molecular weight distribution means that the molecular weight distribution curve on the GPC graph has two peaks. In this case, the two peaks are not separated and exist as independent peaks, but are partially overlapped to form a shoulder peak where there is no minimum value between the maximum values ​​of the two peaks. That is, a bimodal structure is defined as a case where it cannot be interpreted as a single peak forming a normal distribution but can be deconvolved into two distributions.

[0067] Such a bimodal molecular weight distribution implies an increase in the distribution of low and high molecular weights within the polyethylene resin composition. Due to this molecular weight distribution structure, improved physical properties can be exhibited. In particular, compared to polyethylene resin compositions exhibiting a unimodal molecular weight distribution, superior stretchability can be achieved by reinforcing the molecular structure that acts favorably for uniaxial or biaxial stretching.

[0068] Meanwhile, the polyethylene composition of the present invention has the characteristics suitable for manufacturing a stretched film having high shrinkage resistance and printability, while maintaining mechanical properties, productivity, and stretch stability equivalent to or superior to existing ones, by optimizing the slurry polymerization process in the presence of a Ziegler-Natta catalyst or a metallocene catalyst, for example, by optimizing not only the total amount of comonomer but also the ratio of input to each reactor, thereby controlling the balance between mechanical properties and stretchability.

[0069] In the present invention, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are converted values ​​for standard polystyrene measured using gel permeation chromatography (GPC, manufactured by Water). However, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are not limited thereto and may be measured by other methods known in the art to which the present invention belongs. For example, the method for measuring such weight-average molecular weight (Mw) and number-average molecular weight (Mn) is as described in Test Example 1 below.

[0070] A polyethylene composition according to one embodiment of the present invention can produce a stretched film having excellent heat resistance, shrinkage rate, and other film qualities after stretching, along with stretchability, by optimizing the low crystal content, high crystal content, and their ratios as described above.

[0071] Meanwhile, the polyethylene composition may have a degree of crystallinity (Xc) of 65% or more and 95% or less. In addition, the lower limit of the crystallinity (Xc) (%) may be 67, 68, 69, 70, 71.5, 72, 72.5, 73, 73.5, 74, 74.5, 75, 75.5, 76, 76.5, 77, 77.2, 77.4, 77.5, 77.7, 77.8, 77.9, 78, 78.1, 80.3, or 82.5, and the upper limit may be 94, 92, 90, 88 or less, 86, 85.5, 85, 84.5, 83, 83.5, 83, 82.8, 82.6, 82.5, 80.3, 78.1, 78, It may be 77.9, 77.8, 77.7, or 77.5. The degree of crystallization (Xc) (%) may be within the range of any lower limit selected from the lower limits listed above and any upper limit selected from the upper limits listed above.

[0072] In addition, the polyethylene composition may have a melting point (Tm) of 128°C or higher and 136°C or lower, and a crystallization temperature (Tc) of 116°C or higher and 123°C or lower. In addition, the melting point (Tm) may be 128°C or higher, 129°C or higher, 130°C or higher, 130.5°C or higher, 131°C or higher, 131.5°C or higher, or 132°C or higher, and 135.8°C or lower, 135.5°C or lower, 135°C or lower, 134.5°C or lower, 134°C or lower, or 133.5°C or lower. Preferably, the crystallization temperature (Tc) may be 116.5 ℃ or higher, 117 ℃ or higher, 117.5 ℃ or higher, 118 ℃ or higher, 118.5 ℃ or higher, 119 ℃ or higher, 119.5 ℃ or higher, or 120 ℃ or higher, and may be 122.8 ℃ or lower, 122.5 ℃ or lower, 122.3 ℃ or lower, 122 ℃ or lower, 121.8 ℃ or lower, or 121.5 ℃ or lower.

[0073] In the present invention, the degree of crystallization Xc, the melting point Tm, and the crystallization temperature Tc can be measured using a Differential Scanning Calorimeter (DSC, device name: DSC Q20, manufacturer: TA instrument). For example, the method for measuring the melting point Tm, the crystallization temperature Tc, and the degree of crystallization Xc is as described in Test Example 1 below.

[0074] Meanwhile, a polyethylene composition according to one embodiment of the present invention may include one or more ethylene-alpha-olefin copolymers. The ethylene-alpha-olefin copolymer may include, together with ethylene, one or more alpha-olefins selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof. Preferably, the ethylene-alpha-olefin copolymer may be one or more selected from the group consisting of ethylene / 1-hexene copolymers and ethylene / 1-butene copolymers.

[0075] The above-described polyethylene composition can more easily realize the aforementioned physical properties if it is the copolymer described above. However, the type of the above-described polyethylene composition is not limited to the type described above, and it may be provided in various types known in the technical field to which the present invention belongs, as long as it can exhibit the aforementioned physical properties.

[0076] Meanwhile, the ethylene-alpha-olefin copolymer included in the polyethylene composition having the above-mentioned physical properties may be manufactured using a Ziegler-Natta catalyst or a metallocene catalyst, and preferably may be manufactured in the presence of a metallocene catalyst.

[0077] Specifically, the ethylene-alpha-olefin copolymer may be an ethylene-alpha-olefin copolymer prepared by polymerizing an olefin monomer in the presence of a hybrid supported metallocene catalyst comprising: one or more first metallocene compounds selected from compounds represented by the following chemical formula 1; one or more second metallocene compounds selected from compounds represented by the following chemical formula 2; and a carrier supporting the first and second metallocene compounds.

[0078] [Chemical Formula 1]

[0079]

[0080] In the above chemical formula 1,

[0081] M1 is a group 4 transition metal, and

[0082] X 11 , X 12 Each independently, substituted or unsubstituted C 1-20 It is an alkyl or halogen, and

[0083] R1 to R5 and R7 to R 12 Each independently contains hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n1 -OR 13 And,

[0084] R6 is substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n1 -OR 13 However,

[0085] R1 to R 12 At least one of them is -(CH2) n1 -OR 13 And,

[0086] R 13 is substituted or unsubstituted C 1-20 It is alkyl, and

[0087] n1 is an integer from 0 to 10, and

[0088] [Chemical Formula 2]

[0089]

[0090] In the above chemical formula 2,

[0091] M2 is a group 4 transition metal, and

[0092] X 21 , X 22 Each independently, substituted or unsubstituted C 1-20 It is an alkyl or halogen, and

[0093] T2 is C (carbon) or Si (silicon), and

[0094] Q 21 and Q 22 C, each independently substituted or unsubstituted 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n2 -OR 32 Or, Q 21 and Q 22 C that combines with each other to be substituted or unsubstituted 3-20 Forming a cycloalkyl ring,

[0095] R 20 to R 31 Each independently contains hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n2 -OR 32 Or, R 20 to R 31 Among them, two adjacent C's are combined to form a substituted or unsubstituted C' 3-20 Forms a cycloalkyl ring,

[0096] R 20 to R 31 , Q 21 and Q 22 At least one of them is -(CH2) n2 -OR 32 And,

[0097] R 32 is substituted or unsubstituted C1-20 It is alkyl, and

[0098] n2 is an integer from 0 to 10.

[0099] In the present invention, the substituents of the above chemical formula are described in more detail as follows.

[0100] Halogens can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0101] The above C 1-20 The alkyl group may be a straight-chain, branched-chain, or cyclic alkyl group. Specifically, the above C 1-20 The alkyl group may be a straight-chain alkyl having 1 to 20 carbon atoms; a straight-chain alkyl having 1 to 10 carbon atoms; a straight-chain alkyl having 1 to 5 carbon atoms; a branched-chain or cyclic alkyl having 3 to 20 carbon atoms; a branched-chain or cyclic alkyl having 3 to 15 carbon atoms; or a branched-chain or cyclic alkyl having 3 to 10 carbon atoms. More specifically, the alkyl having 1 to 20 carbon atoms may be a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, or a cyclohexyl group, etc.

[0102] C 3-20 The cycloalkyl ring may be a ring composed of carbon atoms. It may be a hydrocarbon ring having 3 to 20 carbon atoms; a hydrocarbon ring having 3 to 15 carbon atoms; or a hydrocarbon ring having 3 to 10 carbon atoms. More specifically, C 3-20 The cycloalkyl ring can be a cyclopropene ring, a cyclobutene ring, a cyclopentene ring, or a cyclohexene ring, etc.

[0103] C 2-20 The alkenyl can be a straight-chain, branched-chain, or cyclic alkenyl. Specifically, the above C 2-20The alkenyl of may be a straight-chain alkenyl having 2 to 20 carbon atoms, a straight-chain alkenyl having 2 to 10 carbon atoms, a straight-chain alkenyl having 2 to 5 carbon atoms, a branched-chain alkenyl having 3 to 20 carbon atoms, a branched-chain alkenyl having 3 to 15 carbon atoms, a branched-chain alkenyl having 3 to 10 carbon atoms, a cyclic alkenyl having 5 to 20 carbon atoms, or a cyclic alkenyl having 5 to 10 carbon atoms. More specifically, C 2-20 The alkenyl of may be ethenyl, propenyl, butenyl, fentenyl, or cyclohexanyl, etc.

[0104] C 1-20 The alkoxy group may be a straight-chain, branched-chain, or cyclic alkoxy group. Specifically, the above C 1-20 The alkoxy group may be a straight-chain alkoxy group having 1 to 20 carbon atoms; a straight-chain alkoxy group having 1 to 10 carbon atoms; a straight-chain alkoxy group having 1 to 5 carbon atoms; a branched-chain or cyclic alkoxy group having 3 to 20 carbon atoms; a branched-chain or cyclic alkoxy group having 3 to 15 carbon atoms; or a branched-chain or cyclic alkoxy group having 3 to 10 carbon atoms. More specifically, the alkoxy group having 1 to 20 carbon atoms may be a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an iso-pentoxy group, a neo-pentoxy group, or a cyclohexoxy group, etc.

[0105] C 2-20 Alkoxyalkyl is -R y -OR z A structure containing alkyl(-R y One or more hydrogens of ) are alkoxy(-OR z It may be a substituent substituted with ). Specifically, the alkoxyalkyl group having C2 to C20 carbon atoms may be a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an iso-propoxyethyl group, an iso-propoxyhexyl group, a tert-butoxymethyl group, a tert-butoxyethyl group, or a tert-butoxyhexyl group, etc.

[0106] C6-60 Aryl may mean monocyclic, bicyclic, or tricyclic aromatic hydrocarbons. Specifically, the C6 to C60 aryl may be a phenyl group, a naphthyl group, or anthracenyl group, etc.

[0107] C 7-20 Alkylaryl may refer to a substituent in which one or more hydrogens of an aryl are substituted by an alkyl group. Specifically, the above C 7-20 The alkylaryl of may be methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl, or cyclohexylphenyl, etc.

[0108] C 7-20 Arylalkyl may refer to a substituent in which one or more hydrogens of an alkyl group are substituted by an aryl group. Specifically, the above C 7-20 The arylalkyl group can be a benzyl group, phenylpropyl or phenylhexyl, etc.

[0109] In addition, group 4 transition metals may include titanium, zirconium, hafnium, etc.

[0110] The above-mentioned hybrid supported metallocene catalyst is a hybrid catalyst comprising a high molecular weight, highly crystalline first metallocene compound and a low molecular weight, low crystalline second metallocene compound.

[0111] In copolymerization in a single reactor using a hybrid supported metallocene catalyst, it is important to control the expression resulting from differences in polymerization characteristics between the metallocene compounds constituting the hybrid supported metallocene catalyst under a single copolymerization condition. In particular, to obtain a polyethylene copolymer for biaxial stretching, high molecular weight, highly crystalline components and low molecular weight, low-crystalline components must be composed together. Accordingly, the present invention invents a polyethylene copolymer that exhibits each characteristic under a single copolymerization condition by using a hybrid supported metallocene catalyst obtained by combining the first metallocene compound and the second metallocene compound.

[0112] The first metallocene compound represented by Chemical Formula 1 above has the characteristic of having a lower polymerization rate of the comonomer and a higher polymerization rate of the ethylene monomer compared to the second metallocene compound due to the structure of the non-bridge type ligand bonded to the central metal. As a result, high molecular weight, highly crystalline polyethylene with a small number of SCBs and a large Mw can be produced under ethylene / 1-hexene copolymerization conditions.

[0113] Meanwhile, the second metallocene compound represented by Chemical Formula 2 has the characteristic of having a high polymerization rate of the comonomer and a low polymerization rate of the ethylene monomer compared to the first metallocene compound due to the bridge-type ligand structure bonded to the central metal. As a result, under ethylene / 1-hexene copolymerization conditions, low molecular weight, low-crystallinity polyethylene with a high SCB and low Mw can be produced.

[0114] Preferably, the central metal (M1) of Formula 1 may be a group 4 transition metal specifically Ti, Zr, or Hf, and more specifically Hf or Zr.

[0115] Preferably, X 11 , X 12 Each can independently be methyl or chloro, and more preferably X 11 , X 12 All of them may be methyl or all of them may be chloro.

[0116] Preferably, R1 to R5 and R7 to R 12 Each independently contains hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-20 Aryl, or -(CH2) n1 -OR 13 And, R6 is substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-20 Aryl, or -(CH2) n1 -OR 13 However, R1 to R 12One or two of them are -(CH2) n1 -OR 13 It could be.

[0117] Preferably, either R7 or R8 is -(CH2) n1 -OR 13 While, the remainder and R1 to R5 and R9 to R 12 Each independently contains hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n1 -OR 13 And, R6 is substituted or unsubstituted C 1-20 Alkyl, substituted, or unsubstituted C 6-60 Aryl, or -(CH2) n1 -OR 13 It could be.

[0118] Preferably, R1 to R5 are each independently hydrogen, methyl, isopropyl, n-butyl, phenyl, or -(CH2) n1 -OR 13 It may be. More preferably, R1 to R5 may each independently be hydrogen, methyl, n-butyl, phenyl, or tert-butoxyhexyl.

[0119] Preferably, R6 is unsubstituted or C 6-10 C substituted with aryl or Si(R')3 1-20 alkyl, or C 6-20 It could be Aril, and here R' is C 1-20 alkyl or C 6-10 It may be an aryl. More preferably, R6 is unsubstituted or C substituted with phenyl, trimethylsilyl, or triphenylsilyl. 1-20 alkyl, or C 6-20 It may be an aryl. Most preferably, R6 may be methyl, ethyl, isopropyl, benzyl, trimethylsilylmethyl, or phenyl.

[0120] Preferably, either R7 or R8 is -(CH2) n1 -OR13 While being, the remainder and R9 to R 12 Each may be hydrogen. More preferably, either R7 or R8 is tertbutoxyhexyl, and the remainder and R9 to R 12 Each can be hydrogen.

[0121] Preferably, R 13 It can be tertbutyl.

[0122] Preferably, n1 can be an integer from 4 to 10, more preferably, n1 can be an integer from 4 to 7, and most preferably, n1 can be 6.

[0123] Preferably, the first metallocene compound represented by the above formula 1 may be any one selected from the group consisting of the following:

[0124]

[0125]

[0126] Meanwhile, the method for preparing the first metallocene compound represented by the above chemical formula 1 is not particularly limited, but, for example, it can be prepared by the method shown in the following reaction formula 1.

[0127] Although the compound represented by the above chemical formula 1 is difficult to synthesize due to the steric hindrance of the indene ligand, the compound of the above chemical formula 1 can be prepared with high yield and high purity according to a method such as the following reaction scheme 1.

[0128] Accordingly, according to one embodiment of the present invention, the compound represented by the chemical formula 1 is,

[0129] A step of preparing a ligand of Formula 1-3 by reacting a compound represented by Formula 1-1 with a compound represented by Formula 1-2; and

[0130] It can be prepared by a manufacturing method comprising the step of reacting a ligand of Chemical Formula 1-3, a compound represented by Chemical Formula 1-4, and a halogen salt of a transition metal represented by Chemical Formula 1-5:

[0131] [Reaction Equation 1]

[0132]

[0133] In the above reaction scheme 1,

[0134] M1, X 11 , X 12 and R1 to R 12 is as defined in the above Chemical Formula 1, and

[0135] X' are each independently halogens.

[0136] Preferably, the central metal (M2) of Formula 2 may be a group 4 transition metal such as Ti, Zr, or Hf, and more specifically, Zr.

[0137] Preferably, X 21 , X 22 Each can independently be methyl or chloro, and more preferably X 21 , X 22 Each can be chloro.

[0138] Preferably, T2 can be C (carbon).

[0139] Preferably, R 20 to R 31 , Q 21 and Q 22 At least one of them is -(CH2) n2 -OR 32 It can be. More preferably, R 20 to R 25 , Q 21 and Q 22 At least one of them is -(CH2) n2 -OR 32 It can be. More preferably, R 20 to R 31 , Q 21 and Q22 One or two of them are -(CH2) n2 -OR 32 It can be. More preferably, R 20 to R 25 , Q 21 and Q 22 One or two of them are -(CH2) n2 -OR 32 It can be. Most preferably, R 20 to R 25 , Q 21 and Q 22 Either one or two of them may be tertbutoxyhexyl.

[0140] Preferably, Q 21 and Q 22 C, each independently substituted or unsubstituted 1-20 Alkyl, substituted, or unsubstituted C 6-20 Aryl, or -(CH2) n2 -OR 32 Or, Q 21 and Q 22 C that combines with each other to be substituted or unsubstituted 3-20 It can form a cycloalkyl ring. More preferably, Q 21 and Q 22 are independently methyl, ethyl, isopropyl, phenyl, or -(CH2) n2 -OR 32 Or, Q 21 and Q 22 They can combine with each other to form a cyclopentene ring or a cyclohexene ring.

[0141] Preferably, R 20 to R 23 Each independently, hydrogen, C 1-20 Alkyl, C 6-20 Aryl, or -(CH2) n2 -OR 32 It can be, and more preferably, R 20 to R 23Each can independently be hydrogen, methyl, n-butyl, phenyl, or tertbutoxyhexyl. More preferably, R 20 to R 23 One is tertbutoxyhexyl or n-butyl, and the rest are hydrogen, or R 20 to R 23 Two of them may each independently be methyl, n-butyl, or phenyl, and the remainder may be hydrogen.

[0142] Preferably, R 24 to R 31 Each independently, hydrogen, C 1-10 Alkyl, C 6-20 Aryl, or -(CH2) n2 -OR 32 Or, R 24 to R 31 Among them, two adjacent C's are combined to form a substituted or unsubstituted C' 3-10 It can form a cycloalkyl ring. More preferably, R 24 to R 31 Each is independently hydrogen, tertbutyl, or tertbutoxyhexyl, or R 24 to R 31 Two adjacent ones can combine to form a cyclohexane ring substituted with four methyl groups.

[0143] Preferably, R 32 It could be tertbutyl.

[0144] Preferably, n2 can be an integer from 4 to 10, more preferably, n2 can be an integer from 4 to 7, and most preferably, n2 can be 6.

[0145] Preferably, the metallocene compound represented by Formula 2 may be any one selected from the group consisting of the following:

[0146]

[0147]

[0148] Meanwhile, the method for preparing the second metallocene compound represented by the above chemical formula 2 is not particularly limited, but, for example, it can be prepared by the method shown in reaction formula 2 below.

[0149] Although the compound represented by the above chemical formula 2 is difficult to synthesize due to the steric hindrance of the fluorene ligand, the compound of the above chemical formula 2 can be prepared with high yield and high purity according to a method such as the following reaction scheme 2.

[0150] Accordingly, according to one embodiment of the present invention, the compound represented by the formula 2 is,

[0151] A step of preparing a compound represented by Chemical Formula 2-3 by reacting a compound represented by Chemical Formula 2-1 with a compound represented by Chemical Formula 2-2;

[0152] A step of preparing a ligand of Formula 2-5 by reacting a compound represented by Formula 2-3 with a compound represented by Formula 2-4; and

[0153] It can be manufactured by a manufacturing method comprising the step of reacting a ligand of chemical formula 2-5 with a halogen salt of a transition metal represented by chemical formula 2-6:

[0154] [Reaction Equation 2]

[0155]

[0156] In the above reaction scheme 2,

[0157] M2, X 21 , X 22 , T2, Q 21 , Q 22 and R 20 to R 31 is as defined in the above Chemical Formula 2, and

[0158] X" are each independently halogens.

[0159] In the hybrid supported metallocene catalyst of the present invention, the first metallocene compound and the second metallocene compound may be supported in a molar ratio of 1:1 to 25:1, 2:1 to 25:1, 3:1 to 25:1, 3:1 to 23:1, or 3:1 to 20:1. If the ratio of the first metallocene compound to the second metallocene compound is less than 1:1, the high crystal content is low, making it difficult for the stretched film to have heat resistance, and if the ratio of the first metallocene compound to the second metallocene compound exceeds 25:1, the low crystal content is low, making it difficult to process into biaxial stretches.

[0160] In the hybrid supported metallocene catalyst of the present invention, a carrier having hydroxyl groups on its surface may be used as a carrier for supporting the first metallocene compound and the second metallocene compound, and preferably, a carrier having highly reactive hydroxyl groups, silanol groups, or siloxane groups on its surface may be used as the carrier, and for this purpose, a carrier that has been surface modified by calcination or has had moisture removed from its surface by drying may be used.

[0161] For example, silica prepared by calcining silica gel, silica dried at high temperatures, silica-alumina, and silica-magnesia may be used, and these may typically contain oxide, carbonate, sulfate, and nitrate components such as Na2O, K2CO3, BaSO4, and Mg(NO3)2.

[0162] When used in the form of a supported catalyst, the particle shape and bulk density of the polymer produced are excellent, and it can be used in conventional slurry polymerization, bulk polymerization, or gas-phase polymerization processes. In addition, among the various supports, since the functional groups of the transition metal compound are chemically bonded and supported on the silica support, there is almost no catalyst released from the surface of the support during the ethylene polymerization process, and as a result, fouling caused by the entanglement of the reactor walls or polymer particles can be minimized when producing ethylene-alpha-olefin copolymers by slurry or gas-phase polymerization.

[0163] The above-mentioned carrier may have an average particle size (D50) of 20 to 60 μm. When having the above-mentioned particle size, transition metal compounds can be supported with superior efficiency, and as a result, catalytic activity can be increased. More specifically, it may be 20 μm or more, or 25 μm or more, and 60 μm or less, or 50 μm or less.

[0164] Meanwhile, in the present invention, the average particle size (D50) of the carrier refers to the particle size at the 50% point of the cumulative distribution of the number of particles according to particle size (particle diameter). The D50 can be measured using a laser diffraction method. Specifically, the carrier to be measured is dispersed in a dispersion medium such as deionized water, and then introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac S3500). The particle size distribution is calculated by measuring the difference in diffraction patterns according to particle size as the particles pass through the laser beam. The particle size at the point that is 50% of the cumulative distribution of the number of particles according to particle size in the measuring device is calculated and used as the average particle size.

[0165] In addition, when supported on the carrier, the first and second metallocene compounds may be supported in a content range of, for example, 1 mmol or more, 10 mmol or more, 15 mmol or more, 20 mmol or more, 25 mmol or more, or 30 mmol or more, respectively, based on 1,000 g of the carrier, and 500 mmol or less, 400 mmol or less, 300 mmol or less, 200 mmol or less, 100 mmol or less, 80 mmol or less, 60 mmol or less, or 52.5 mmol or less. When supported within the above content range, appropriate supported catalyst activity is exhibited, which may be advantageous in terms of maintaining catalyst activity and economic efficiency.

[0166] In addition, the above hybrid metallocene catalyst may further include a co-catalyst to improve high activity and process stability.

[0167] The above co-catalyst is an organometallic compound containing a Group 13 metal, and specifically may include one or more of the compounds represented by the following chemical formula 3.

[0168] [Chemical Formula 3]

[0169] -[Al(R 41 )-O]a-

[0170] In the above chemical formula 3,

[0171] R 41 is a halogen; or C substituted or unsubstituted with a halogen 1-20 It is hydrocarbil;

[0172] a is an integer greater than or equal to 2.

[0173] Meanwhile, in this specification, the hydrocarbyl group is a monovalent functional group in which a hydrogen atom has been removed from a hydrocarbon, and may include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, aralkyl groups, aralkenyl groups, aralkinyl groups, alkylaryl groups, alkenylaryl groups, and alkynylaryl groups, etc. Furthermore, the hydrocarbyl group having 1 to 20 carbon atoms may be a hydrocarbyl group having 1 to 15 carbon atoms or 1 to 10 carbon atoms. Specifically, the hydrocarbyl group having 1 to 20 carbon atoms is a straight-chain, branched-chain, or cyclic alkyl group such as a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, or a cyclohexyl group; Or it may be an aryl group such as a phenyl group, a naphthyl group, or anthracenyl group.

[0174] Examples of compounds represented by the above chemical formula 3 include alkylaluminoxan compounds such as methylaluminoxan, ethylaluminoxan, isobutylaluminoxan, or butylaluminoxan, and any one or more of these may be used.

[0175] Among the compounds mentioned above, the co-catalyst may be, more specifically, an alkylaluminoxan-based co-catalyst such as methylaluminoxan.

[0176] The above alkylaluminoxane-based co-catalyst can further enhance catalytic activity by including a metal element that stabilizes the first and second metallocene compounds and acts as a Lewis acid to form a bond through Lewis acid-base interaction with the functional group introduced into the bridge group of the first and second metallocene compounds.

[0177] In addition, the amount of the above co-catalyst used can be appropriately adjusted according to the physical properties or effects of the desired catalyst and polyethylene copolymer. For example, when silica is used as the carrier, the above co-catalyst can be supported in an amount of 100g or more, 1000g or more, or 2000g or more, and 6000g or less, or 5500g or less, or 5400g or less, based on 1000g of silica.

[0178] A hybrid metallocene catalyst according to the present invention having the above-described composition can be manufactured by a manufacturing method comprising the steps of: supporting a co-catalyst compound on a carrier; and supporting the first and second transition metal compounds on the carrier. In this case, the order of supporting the co-catalyst and the first and second transition metal compounds may be changed as needed, and the order of supporting the first and second transition metal compounds may also be changed as needed. The first and second transition metal compounds may be supported simultaneously. Considering the effect of the supported catalyst with a structure determined by the order of support, among these, sequentially supporting the first and second transition metal compounds after supporting the co-catalyst on the carrier allows the manufactured supported catalyst to achieve superior process stability along with high catalytic activity in the manufacturing process of an ethylene-alpha-olefin copolymer.

[0179] As described above, the hybrid supported metallocene catalyst can exhibit excellent catalytic activity by including first and second metallocene compounds having a specific structure. Accordingly, the hybrid supported metallocene catalyst can be suitably used for the polymerization of ethylene and olefin monomers.

[0180] In addition, the hybrid supported metallocene catalyst may be added in an amount of 2% or less or 0 to 2% or less based on the total weight of ethylene. Specifically, the total amount of the co-catalyst, such as the alkyl aluminum compound, may be 1.8% or less, 1.5% or less, 1.2% or less, or 1% or less, and may also be added in an amount of 0.001% or more, 0.005% or more, or 0.01% or more.

[0181] Meanwhile, alpha-olefins may be used as the olefin monomers polymerized together with ethylene. Specific examples of such alpha-olefins include 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, or 1-eicocene, and two or more of these monomers may be copolymerized. More specifically, the olefin monomers may be one or more of 1-butene and 1-hexene.

[0182] The amount of the olefin monomer added may be determined according to the physical properties of the polyethylene copolymer to be manufactured. For example, when considering the physical properties of the polyethylene copolymer to be realized in the present invention, the olefin monomer may be added in an amount of 5% by weight or less or 0 to 5% by weight or less relative to the total weight of ethylene. For example, in the case of a bimodal slurry polymerization process, the total amount of olefin monomer added in each reactor, which is the sum of the olefin monomers added in each reactor, may be 5% by weight or less relative to the total weight of ethylene, which is the sum of the ethylene added in each reactor. Specifically, the total input amount of the olefin monomer may be 4.5 wt% or less, 4 wt% or less, 3.8 wt% or less, 3.5 wt% or less, 3.2 wt% or less, 3 wt% or less, 2.8 wt% or less, 2.5 wt% or less, 2.2 wt% or less, 2 wt% or less, 1.8 wt% or less, 1.5 wt% or less, 1.1 wt% or less, or 0.7 wt% or less relative to the total input amount of ethylene. Additionally, the total input amount of the olefin monomer may be 0.05 wt% or more, 0.1 wt% or more, 0.15 wt% or more, 0.2 wt% or more, 0.25 wt% or more, 0.4 wt% or more, 0.7 wt% or more, or 1.1 wt% or more relative to the total input amount of ethylene.

[0183] In addition, the total input amount of the olefin monomer may be 0.2 volume% or more, 0.24 volume% or more, or 0.36 volume% or more relative to the total input amount of ethylene, and may be 1 volume% or less, 0.84 volume% or less, 0.61 volume% or less, or 0.37 volume% or less. The total input amount of the olefin monomer may be within the range of any one lower limit selected from the lower limits listed above and any one upper limit listed above.

[0184] The ratio of the low-crystallinity fraction peak area to the total peak area (CEF) when the input amount of the olefin monomer, which is the comonomer, is within the above range ≤95℃≥70℃), ratio of the peak area of ​​the highly crystalline fraction to the total peak area (CEF ≥100℃ ), and the ratio of the low-crystallinity fraction peak areas (CEF ≤95℃≥70℃ Ratio of the peak area of ​​the highly crystalline fraction to ) (CEF ≥100℃ The ratio of ) can be optimized simultaneously.

[0185] The above polymerization reaction is carried out under conditions of hydrogen input.

[0186] Specifically, the hydrogen may be introduced at a concentration of 20 to 250 ppm based on the total weight of the monomer, ethylene. More specifically, based on the total weight of ethylene, the hydrogen may be introduced at a concentration of 20 ppm or more, 50 ppm or more, 70 ppm or more, 86 ppm or more, 105 ppm or more, 130 ppm or more, or 165 ppm or more, and at 250 ppm or less, 200 ppm or less, 165 ppm or less, 135 ppm or less, 105 ppm or less, or 85 ppm or less. The amount of hydrogen introduced may be within the range of any one lower limit selected from the listed lower limits and any one upper limit among the listed upper limits. Additionally, the amount of hydrogen introduced may be calculated based on a liquid ethylene density of 0.62 g / mL. When introduced within the above range, it is easier to realize the physical properties of the aforementioned polyethylene copolymer.

[0187] The above polymerization reaction can be carried out as a gas phase polymerization reaction or a slurry polymerization reaction.

[0188] Accordingly, it can be carried out using a single gas phase polymerization reactor, a continuous slurry polymerization reactor, or a loop slurry reactor.

[0189] In addition, the above-mentioned hybrid supported catalyst may be dissolved or diluted and injected in an aliphatic hydrocarbon solvent having 4 to 12 carbon atoms, such as isobutane, pentane, hexane, heptane, octane, nonane, decane, and their isomers, an aromatic hydrocarbon solvent such as toluene and benzene, or a hydrocarbon solvent substituted with chlorine atoms such as dichloromethane and chlorobenzene. It is preferable to use a solvent that removes small amounts of water or air, which act as catalyst poisons, by treating it with a small amount of alkyl aluminum, and it is also possible to carry out the process using additional co-catalysts.

[0190] Non-limiting examples of such alkyl aluminum compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylaluminum methoxide, or dimethylaluminum ethoxide.

[0191] In addition, the co-catalyst, such as the alkyl aluminum compound, may be introduced in an amount of 2% by weight or less or 0 to 2% by weight or less based on the total weight of the monomer, ethylene. Specifically, the total amount of the co-catalyst, such as the alkyl aluminum compound, may be 1.8% by weight or less, 1.5% by weight or less, 1.2% by weight or less, or 1% by weight or less, and may also be introduced in an amount of 0.01% by weight or more, 0.02% by weight or more, or 0.05% by weight or more.

[0192] In addition, the polymerization reaction may be carried out at a temperature of 40°C or higher, or 60°C or higher, or 80°C or higher, and at 110°C or lower, or 100°C or lower, or 90°C or lower. Furthermore, if the pressure conditions during the polymerization reaction are further controlled, the reaction may be carried out at a pressure of 5 bar or higher, or 10 bar or higher, or 20 bar or higher, and at 50 bar or lower, or 45 bar or lower, or 40 bar or lower. When polymerization proceeds under these temperatures and pressures, the desired physical properties of the ethylene-alpha-olefin copolymer can be more easily realized.

[0193] The above ethylene-alpha-olefin copolymer is prepared using a catalyst in which a metallocene compound exhibiting high molecular weight and high crystallinity and a metallocene compound exhibiting low molecular weight and low crystallinity are hybridized and supported together. This allows for the high crystallinity content and low crystallinity content to be optimized and controlled to an appropriate level when the relative ratio of crystal fraction peak areas eluted according to temperature (°C) is measured by CEF analysis. Accordingly, when a stretched film is manufactured using a polyethylene composition containing one or more of the above ethylene-alpha-olefin copolymers, heat resistance such as stretching stability and shrinkage rate can be improved along with the mechanical properties of the stretched film.

[0194] Accordingly, the present invention provides a uniaxially or biaxially stretched film comprising a polyethylene composition comprising one or more of the above-mentioned ethylene-alpha-olefin copolymers.

[0195] (Continuous film)

[0196] A stretched film according to one embodiment of the present invention may be formed by stretching a polyethylene composition sheet comprising the polyethylene composition. A polyethylene composition having the above-described physical properties can stably form a uniaxial or biaxially stretched film having high shrinkage resistance and excellent printability, while maintaining excellent mechanical properties, productivity, and stretching stability.

[0197] In particular, uniaxially-oriented polyethylene (UPE) films provide high tensile strength and stiffness in the machine direction (MD), and have the advantage of extending shelf life due to excellent transparency and low gas and moisture permeability. These uniaxially-oriented polyethylene (UPE) films have excellent tear resistance due to their unidirectional orientation and can be effectively applied to easy-cut products, which are widely used as packaging materials recently.

[0198] In addition, biaxially-oriented polyethylene (BOPE) films stretch in both the mechanical and transverse directions, providing balanced strength, durability, and tear resistance in all directions. These BOPE films offer greater versatility in packaging applications requiring high puncture resistance and dimensional stability.

[0199] Meanwhile, the above-mentioned stretched film can be manufactured by a conventional film manufacturing method, except for using the above-mentioned polyethylene composition.

[0200] The above-mentioned stretched film exhibits excellent stretchability and improved shrinkage resistance by including the aforementioned polyethylene.

[0201] Specifically, the stretched film may be a polyethylene composition sheet with a width * length of 90 mm * 90 mm and a thickness of 200 μm, and when uniaxially stretched under a stretching speed of 200% / s after preheating at 126 ℃ for 60 seconds, the maximum stretching ratio may be 8 or more, 9 or more, or 10 or more.

[0202] In addition, when the above-mentioned stretched film is subjected to a film shrinkage test by heating it to 120°C at a heating rate of 5°C / min using a Dynamic Mechanical Analysis (DMA) device and leaving it for 1 hour, the shrinkage rate (%, [(AB) / A] x 100), which is the difference between the initial film length (A, unit mm) measured before the film shrinkage test and the film length (B, unit mm) after the film shrinkage test, expressed as a percentage, may be 4% or less, 3.8% or less, 3.6% or less, 3.5% or less, 3.4% or less, or 3.2% or less.

[0203] For example, the stretched film may be a uniaxially stretched film having a machine direction (MD) or transverse direction (TD) stretching ratio of 5 or more or 5 to 10 when the thickness is 10 μm to 100 μm. Alternatively, the stretched film may be a biaxially stretched film having a machine direction (MD) stretching ratio of 5 or more or 5 to 8 and a transverse direction (TD) stretching ratio of 8 or more or 8 to 10.

[0204] Here, the stretching ratio of the stretched film may be a value measured when the thickness of the film is 10 μm to 100 μm, for example, 20 μm to 95 μm, or 30 μm to 90 μm, or 40 μm to 85 μm.

[0205] In addition, the polyethylene stretched film according to the present invention can be manufactured by performing uniaxial stretching or biaxial stretching after manufacturing a polyethylene composition sheet. The polyethylene composition sheet can be manufactured using a high-temperature press at 190°C to a thickness of 150 μm to 250 μm, for example, 200 μm. Here, any product known to be capable of manufacturing a polyethylene sheet under the temperature conditions described above can be used as the high-temperature press; specifically, a high-temperature press (Manufacturer: Collin, Product Name: Lab line P300S) can be used. After manufacturing the polyethylene composition sheet as described above, the polyethylene stretched film can be manufactured by performing uniaxial stretching or biaxial stretching on a polyethylene composition sheet with dimensions of 80 mm to 100 mm in width and length, for example, 90 mm in width and 90 mm in length, using KARO 5.0 equipment. The specific film manufacturing method and conditions are as described in Test Example 2 below.

[0206] The above-described polyethylene stretched film may further include additives well known in the art in addition to the polyethylene composition described above. Specifically, such additives include solvents, heat stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, fillers, reinforcing agents, plasticizers, lubricants, emulsifiers, pigments, optical bleaching agents, flame retardants, antistatic agents, foaming agents, etc. The types of the above additives are not particularly limited, and general additives known in the art may be used.

[0207] The polyethylene stretched film according to one embodiment of the present invention, manufactured by the above-described method, can not only improve film productivity with excellent stretchability, but also improve performance with excellent film strength and shrinkage rate with excellent heat resistance.

[0208] Here, the physical properties of the stretched film may be values ​​measured when the thickness of the film is 10 μm to 100 μm, for example, 12 μm to 85 μm, or 15 μm to 50 μm, or 18 μm to 45 μm, or 20 μm to 35 μm. Specifically, the stretched film may be uniaxially stretched in the MD direction or stretched at a stretching ratio of 5X8 (MD X TD), and the thickness may be measured as about 20 μm to about 30 μm.

[0209] In the present invention, the physical properties of the stretched film can be evaluated according to the specifications described above, and the specific method is as described in Test Example 2 below.

[0210] In the present invention, as described above, by controlling the balance between mechanical properties and stretchability through a unimodal or bimodal slurry polymerization process using a Ziegler-Natta catalyst or a metallocene catalyst to achieve excellent mechanical properties along with excellent stretchability, it is possible to stably manufacture a stretched film having high shrinkage resistance and excellent printability while maintaining excellent mechanical properties, productivity, and stretch stability.

[0211] Hereinafter, embodiments of the present invention will be described in more detail in the following examples. However, the following examples are merely illustrative of embodiments of the present invention, and the content of the present invention is not limited by the following examples.

[0212] [Example]

[0213] Preparation of Metallocene Compounds

[0214] Synthesis Example 1: Preparation of Metallocene Compound A1

[0215]

[0216] (1) Synthesis of ligands

[0217] Under Ar, 120 g (440 mmol) of 3-(6-tert-butoxyhexyl)-1H-indene and 1.1 L of n-hexane were added to a dried 2 L Schlenk flask. After cooling to -78 °C, 185 mL (1.05 eq., 462.5 mmol) of 2.5 M n-BuLi in hexane was added dropwise. The reaction mixture was slowly heated to room temperature and stirred for 8 hours. After cooling again to -78 °C, 82.8 g (1.1 eq., 484 mmol) of benzyl bromide was added dropwise. After slowly raising the temperature to room temperature and stirring for 24 hours, the organic layer was separated using water and diethyl ether and dried with MgSO4 to obtain 137 g (377 mmol, 85.7% yield) of 3-(6-tert-butoxyhexyl)-1-benzyl-1H-indene.

[0218] 1 H NMR (500 MHz, CDCl3): 1.22 (9H, s), 1.32 (4H, m), 1.44 (2H, m), 1.57 (2H, m), 1.73 (2H, m), 2.59 (2H, m), 3.38 (2H, t), 3.75 (1H, m), 6.14 (1H, brs), 7.14-7.45 (9H, m).

[0219] (2) Synthesis of metallocene compounds

[0220] Under Ar, 9.06 g (25 mmol) of the ligand synthesized above and 90 mL of diethyl ether were added to a dried 250 mL Schlenk flask. After cooling to -78 °C, 11 mL (1.05 eq., 27.5 mmol) of 2.5 M n-BuLi in hexane was added dropwise. The reaction mixture was slowly heated to room temperature and stirred for 8 hours. After cooling again to -78 °C, 10.6 g (1.0 eq., 25 mmol) of (1-n-butyl-3-methylcyclopentadienyl)ZrCl3-dimethoxyethane complex was added along with 30 mL of diethyl ether. After slowly heating to room temperature and stirring for 24 hours, the reaction mixture was dried under reduced pressure and dichloromethane was added. The resulting suspension was filtered under Ar to remove LiCl, the filtrate was dried under reduced pressure, and n-hexane was added. The resulting suspension was filtered under Ar to obtain 8.76 g (13.3 mmol, 53.2% yield) of solid metallocene compound A1.

[0221] 1 H NMR (500 MHz, CDCl3): 0.88-0.91 (3H, m), 1.22 (9H, s), 1.29-1.40 (8H, m), 1.52-1.76 (4H, m), 2.06 (3H, s), 2.11-2.22 (2H, m), 2.59-2.68 (2H, m), 2.99-3.07 (2H, m), 3.34 (2H, t), 4.43 (1H, dt), 5.21 (1H, dt), 5.78 (1H, t), 6.47 (1H, brs), 7.11-7.63 (9H, m).

[0222] Synthesis Example 2: Preparation of Metallocene Compound B1

[0223]

[0224] (1) Synthesis of ligands

[0225] Under Ar, 5.01 g (18 mmol) of 2,7-di-tert-butylfluorene and 80 mL of tetrahydrofuran were added to another dry 250 mL Schlenk flask. After cooling to -78 °C, 8.6 mL (1.2 eq., 21.5 mmol) of 2.5 M n-BuLi in hexane was added dropwise. The reaction mixture was slowly heated to room temperature and stirred for 8 hours. After cooling to -78 °C, 5.73 g (1.0 eq., 18 mmol) of 2-(6-tert-butoxyhexyl)-5-(2,4-dimethylpentan-3-ylidene)-cyclopenta-1,3-diene was added along with 10 mL of tetrahydrofuran. After slowly raising the temperature to room temperature and stirring for 24 hours, the organic layer was separated using water and diethyl ether and dried with MgSO4 to obtain 6.92 g of ligand (11.6 mmol, 64.4% yield).

[0226] 1 H NMR (500 MHz, CDCl3): 0.85 (12H, d), 1.14 (9H, s), 1.27 (18H, s), 1.31-1.60 (10H, m), 2.22 (2H, m), 2.92 (2H, m), 3.33 (2H, t), 3.76 (1H, brs), 6.11 (1H, m), 6.35 (1H, brs), 7.40 (2H, m), 7.49-7.62 (2H, m), 7.78-7.91 (2H, m).

[0227] (2) Synthesis of metallocene compounds

[0228] Under Ar, 6.92 g (11.6 mmol) of the ligand synthesized above, 10 mL of methylt-butyl ether, and 40 mL of toluene were added to a dried 250 mL Schlenk flask. After cooling to -78 °C, 10.2 mL (2.2 eq., 25.5 mmol) of 2.5 M n-BuLi in hexane solution was added dropwise. The reaction mixture was slowly heated to room temperature and stirred for 8 hours. After cooling to -78 °C, 24.38 g (1.0 eq., 11.6 mmol) of ZrCl4(THF) was added along with 10 mL of methylt-butyl ether. After slowly heating to room temperature and stirring for 24 hours, the reaction mixture was dried under reduced pressure at room temperature to remove the methylt-butyl ether. The generated toluene suspension was filtered under Ar to remove LiCl, and the filtrate was dried under reduced pressure at 50 °C and n-hexane was added. The generated suspension was filtered under Ar to obtain 4.12 g (5.44 mmol, 46.9% yield) of solid metallocene compound B1.

[0229] 1 H NMR (500 MHz, C6D6): 0.90 (12H, d), 1.12 (9H, s), 1.15-1.38 (24H, m), 1.44-1.55 (6H, m), 3.21 (2H, t), 5.30-6.15 (3H, m), 7.44 (2H, dd), 7.65 (2H, d), 7.91 (2H, d).

[0230] Preparation of Supported Catalysts

[0231] Catalyst Preparation Example 1: Preparation of Hybrid Supported Metallocene Catalyst 1

[0232] Silica (SP 952, manufactured by Grace Davision) was dehydrated and dried under vacuum at a temperature of 200°C for 12 hours.

[0233] 800 g of dried silica was placed in a 20 L SUS reactor, and 6 kg of methylaluminoxan (MAO) solution (10 wt% in toluene) was added to the toluene solution and reacted slowly at 70 °C for 1 hour with stirring. After the reaction was complete, the unreacted aluminum compound was washed several times with a sufficient amount of toluene until it was completely removed. A solution prepared by dissolving 30.1 g of metallocene compound A1 and 3.0 g of metallocene compound B1 in toluene was sequentially added to the reactor and reacted at 40 °C for 4 hours with stirring. At this time, the ratio of the molar amount of metallocene compound A1 to the molar amount of metallocene compound B1 became 12. Then, after the reaction was completed and the mixture was washed with a sufficient amount of toluene, it was vacuum dried to obtain hybrid supported metallocene catalyst 1 as a solid powder.

[0234] <Preparation of Polyethylene Composition>

[0235] Example 1

[0236] The polyethylene composition of Example 1 was slurry polymerized through a bimodal polymerization process using two 100L continuous stirred tank reactors (CSTR) in the presence of the hybrid supported catalyst 1 prepared in the above catalyst preparation example 1.

[0237] Specifically, in the first reactor, a primary polymerization reaction was performed by controlling the input amounts of hydrogen and comonomer according to the conditions listed in Table 1 below to produce the first polyethylene. At this time, 110 mL / hr of triethylaluminum (TEAL) at a concentration of 0.3 mM was used as a co-catalyst. The first polyethylene polymerized in the first reactor was transferred to a second reactor connected in series, and a secondary polymerization reaction was performed by controlling the input amounts of hydrogen and comonomer according to the conditions listed in Table 1 below. At this time, all inputs listed in Table 1 below were continuously fed for the same amount of time.

[0238] Based on the total weight of the polymerization product obtained as a result of this secondary polymerization reaction, 200 ppm of BASF’s Irganox 1010 as a primary antioxidant, 400 ppm of BASF’s Irgafos 168 as a secondary antioxidant, and 500 ppm of calcium stearate (Ca-St) or DHT4A as a neutralizing agent were added and mixed, and then extruded at an extrusion temperature of 190 ℃ using a twin screw extruder (TEK 30 MHS, manufactured by SMPLATECH CO., diameter 32 phi, L / D=40) to prepare the pelletized polyethylene composition of Example 1.

[0239] Examples 2 to 5

[0240] Polyethylene compositions of Examples 2 to 5 were prepared in the same manner as Example 1, except that the polyethylene composition was polymerized in a slurry as described in Example 1 above, but the first reactor polymerization was performed with different amounts of hydrogen and comonomer input under the conditions listed in Table 1 below, and the unimodal slurry polymerization process was performed without the second reactor polymerization.

[0241] Reactor 1 Reactor 2 Ethylene [ml / min] 1-Butene [ml / min] 1-Hexene [ml / min] Hydrogen [g / hr] TEAL [ml / hr] Ethylene [ml / min] 1-Butene [ml / min] 1-Hexene [ml / min] Hydrogen [g / hr] TEAL [ml / hr] Example 1 50002511040002140 Example 2 700203.0120-----Example 3 700022.5130-----Example 4 700202.0140-----Example 5 700022.0120-----

[0242]

[0243] Comparative Example 1

[0244] High-density polyethylene resin (manufacturer Exxon, product name HTA108) was prepared as Comparative Example 1.

[0245] Comparative Example 2

[0246] High-density polyethylene resin (manufacturer DOW, product name Elite5960G) was prepared as Comparative Example 2.

[0247] Comparative Example 3

[0248] High-density polyethylene resin (manufacturer SK Innovation, product name Yuzex8300) was prepared as Comparative Example 3.

[0249] Comparative Example 4

[0250] High-density polyethylene resin (manufacturer DOW, product name AT6900) was prepared as Comparative Example 4.

[0251] Comparative Examples 5 to 13

[0252] Polyethylene compositions of Comparative Examples 5 to 13 were each prepared in the same manner as in Example 1, except that the polyethylene composition was polymerized into a slurry through a bimodal polymerization process as described in Example 1 above, and the amounts of hydrogen and comonomer input were adjusted differently according to the conditions listed in Table 2 below.

[0253] Comparative Example 14

[0254] The polyethylene composition of Comparative Example 14 was prepared in the same manner as Example 1, except that the polyethylene composition was slurry polymerized as described in Example 1 above, but the first reactor polymerization was performed with different amounts of hydrogen and comonomer input under the conditions listed in Table 1 below, and the unimodal slurry polymerization process was performed without the second reactor polymerization.

[0255] First Reactor Second Reactor Ethylene [ml / min] 1-Butene [ml / min] 1-Hexene [ml / min] Hydrogen [g / hr] TEAL [ml / hr] Ethylene [ml / min] 1-Butene [ml / min] 1-Hexene [ml / min] Hydrogen [g / hr] TEAL [ml / hr] Comparative Example 5 5000 5470 4000 2120 Comparative Example 6 5000 610 70 4000 2570 Comparative Example 7 50020513040020250Comparative Example 850040410040040250Comparative Example 950002610040002470Comparative Example 105008085040011530Comparative Example 1150010115040000130Comparative Example 125006655040004530Comparative Example 1350010912040000240Comparative Example 14700206130-----

[0256]

[0257] <Test Example 1: Evaluation of Physical Properties of Polyethylene Composition>

[0258] The physical properties of the polyethylene compositions prepared in the examples and comparative examples were evaluated using the method described below and are shown in Table 3.

[0259] (1) Melt index

[0260] Melt index (MI) at 190°C under a 2.16 kg load according to ASTM D 1238 (Condition E, 190°C, 2.16 kg). 2.16 ) was measured (measuring equipment: Gottfert MI-4), and expressed as the weight (g) of the polyethylene composition melted over 10 minutes.

[0261] (2) Density

[0262] According to ISO 1183-2 standards, density (g / cm³) at 23 ℃ 3 ) was measured.

[0263] (3) Number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)

[0264] For the polyethylene compositions prepared in the examples and comparative examples, the weight-average molecular weight (Mw, g / mol) and number-average molecular weight (Mn, g / mol) were measured using gel permeation chromatography (GPC, manufactured by Water) in accordance with the American Society for Testing Materials standard ASTM D 6474, and the molecular weight distribution (Mw / Mn, PDI, polydispersity index) was calculated by dividing the weight-average molecular weight by the number-average molecular weight.

[0265] Specifically, a Waters PL-GPC220 instrument was used for gel permeation chromatography (GPC), and a Polymer Laboratories PLgel MIX-B 300 mm long column was used. The measurement temperature was 160 ℃, 1,2,4-trichlorobenzene was used as the solvent, and the flow rate was set to 1 mL / min. Each sample of the ethylene-alpha-olefin copolymer prepared in Preparation Examples 1 to 4 was pretreated by dissolving it in trichlorobenzene containing 0.0125% BHT at 160 ℃ for 3 hours using the GPC analyzer (PL-GP220), prepared to a concentration of 32 mg / 10 mL, and supplied in an amount of 200 μL. The values ​​of Mw and Mn were derived using a calibration curve formed using a polystyrene standard specimen. Nine types of polystyrene standard specimens with weight-average molecular weights of 2000 g / mol, 10000 g / mol, 30000 g / mol, 70000 g / mol, 200000 g / mol, 700000 g / mol, 2000000 g / mol, 4000000 g / mol, and 10000000 g / mol were used.

[0266] (4) Melting temperature (Tm), crystallization temperature (Tc) and degree of crystallization (%)

[0267] The melting temperature (Tm), crystallization temperature (Tc), and crystallinity (Xc) of the polyethylene compositions of the examples and comparative examples were measured using a differential scanning calorimeter (DSC, device name: DSC Q20, manufacturer: TA instrument).

[0268] Specifically, the temperature was increased to heat the polyethylene composition to 180 °C at a rate of 10 °C / min (Cycle 1), and after isothermal at 180 °C for 5 minutes, it was cooled to 0 °C at a rate of 10 °C / min, and then heated again to 180 °C at a rate of 10 °C / min after isothermal at 30 °C for 5 minutes (Cycle 2). In the DSC curve obtained through this process, the temperature at the point of maximum endothermic peak was measured as the melting temperature (Tm, °C), and the temperature at the point of maximum exothermic peak was measured as the crystallization temperature (Tc, °C). At this time, the melting temperature (Tm) and crystallization temperature (Tc) are the results measured in the second temperature rising and falling sections (Cycle 2), respectively.

[0269] In addition, Heat of Fusion △Hm was calculated using the area of ​​the melting peak in the second temperature increase section (Cycle 2), and the degree of crystallization (Xc, %) was calculated by dividing it by the theoretical value H0m = 293.6 J / g when the degree of crystallization is 100%.

[0270] (5) High crystal content and low crystal content

[0271] For the polyethylene compositions of the examples and comparative examples, crystallization elution fraction (CEF) analysis was performed to measure the crystallization fraction content leached at 100°C or higher, i.e., 100°C or higher and 105°C or lower, i.e., the high crystallization content, and the crystallization fraction content leached at 70°C or higher and 95°C or lower, i.e., the low crystallization content.

[0272] Specifically, this can be obtained using the PolymerChar Agilent Technologies 7890A instrument. For example, a sample is dissolved in 20 mL of 1,2,4-trichlorobenzene at a concentration of 1.5 mg / mL, then dissolved while increasing the temperature from 30 °C to 150 °C at a rate of 40 °C / min, then recrystallized while decreasing the temperature to 20 °C at a rate of 0.5 °C / min, and then the elution amount is measured while increasing the temperature again to 140 °C at a rate of 1 °C / min. At this time, the weight fraction W obtained according to the elution temperature T is normalized against the total integral value (20 to 140 °C) obtained by integrating the dW / dT value with respect to temperature to obtain the fraction (%) according to temperature. This can be represented as a crystallization elution fraction (CEF) graph where the x-axis is the elution temperature (°C) and the y-axis is the fraction (%). The crystallization elution fraction (CEF) graph obtained in this way represents the relative ratio of the elution fraction peak areas according to temperature (°C).

[0273] In this CEF curve graph, with the total peak area set to 100%, the ratio of the peak area in the region where the temperature is 100°C or higher, specifically between 100°C and 105°C, is the high crystal content (CEF ≥100℃ It was expressed as ), and the ratio of the crystal fraction peak area eluted at 70 ℃ to 95 ℃ was the low crystal content (CEF ≤95℃≥70℃ It was represented as ).

[0274] In addition, the low crystallinity (CEF) measured as described above for the polyethylene compositions of Examples 1 to 5 and Comparative Examples 1 to 14 ≤95℃≥70℃ ) and high crystallinity content (CEF ≥100℃ The ratio of the two crystal contents described above from ), i.e., high crystal ratio / low crystal ratio (CEF ≥100℃ / CEF ≤95℃≥70℃ ) was estimated.

[0275] MI [g / 10min] Density [g / cm² 3]Mw[g / mol]PDI(Mw / Mn)Degree of Crystallinity[%]Low Crystalline Ratio[%]High Crystalline Ratio[%]High Crystalline Ratio / Low Crystalline Ratio Example 1 0.85 0.96 2146,600 9.65 78.12 1.27 9.63 0.45 Example 2 1.085 0.96 1123,300 6.53 82.6 18.01 7.97 0.44 Example 3 0.933 0.95 9128,500 6.56 78.01 7.53 8.35 0.48 Example 4 0.673 0.96 0134,100 6.44 77.41 4.46 12.57 0.87 Example 50.5210.958138,8006.1478.014.7610.150.69 Comparative Example 10.700.961133,0008.7377.528.163.710.13 Comparative Example 20.850.96298,2004.3677.017.003.160.19 Comparative Example 30.700.963159,7009.3982.523.722.020.09 Comparative Example 41.200.969108,00013.483.038.717.690.20 Comparative Example 50.900.952144,70011.2970.759.030.010.00Comparative Example 61.340.967129,00035.691.540.204.310.11Comparative Example 71.10.956122,7005.1177.816.362.250.14Comparative Example 81.10.952120,0004.9673.927.780.380.01Comparative Example 920.952101,3004.9174.639.100.120.00Comparative Example 101.300.947122,70010.367.842.780.260.01Comparative Example 110.450.965164,0007.1284.19.0113.201.47Comparative Example 122.910.935107,3005.6364.514.36.260.44Comparative Example 131.250.971117,60011.180.024.98.580.34Comparative Example 143.00.96397,0007.0978.822.45.800.26

[0276]

[0277] Meanwhile, among the crystallization elution fraction (CEF) graphs obtained as described above, the crystallization elution fraction (CEF) graph for the polyethylene compositions of Example 1 and Comparative Example 1 is shown in FIG. 1. In addition, the high crystallinity content (CEF) measured as described above for the polyethylene compositions of Examples 1 to 5 and Comparative Examples 1 to 10 ≥100℃ ) and low crystallinity content (CEF ≤95℃≥70℃ A distribution graph showing the correlation with ) as the y-axis and x-axis, respectively, is shown in FIG. 2. In FIG. 2, Examples 1 to 5 are each indicated as points 1 to 5 in the graph, and Comparative Examples 1 to 10 are each indicated as points 6 to 15 in the graph.

[0278] According to FIG. 1, Example 1 and Comparative Example 1 also appear to have some similar CEF graphs. However, as shown in FIG. 2, the high crystal content (CEF ≥100℃ ) and low crystallinity content (CEF ≤95℃≥70℃ When examining the distribution graph showing the correlation, it can be confirmed that there is a clear difference. In particular, as shown in FIG. 2, when measuring the relative ratio of the crystal fraction peak area eluted according to temperature, the polyethylene compositions of Examples 1 to 5 showed a high crystal content (CEF) compared to Comparative Examples 1 to 10. ≥100℃ ) and low crystallinity content (CEF ≤95℃≥70℃ By optimizing ), it is possible to improve heat resistance and minimize shrinkage at high temperatures while maintaining excellent stretchability with a high maximum stretch ratio during film manufacturing.

[0279] <Test Example 2: Preparation of Stretched Film and Evaluation of Physical Properties>

[0280] After preparing stretched films using the polyethylene compositions obtained in the examples and comparative examples in the following manner, the physical properties of each were measured and are shown in Table 4.

[0281] Manufacturing of stretched film

[0282] - A polyethylene composition sheet was prepared to a thickness of 200 μm at 190 ℃ using a high-temperature press (Manufacturer: Collin, Product Name: Lab line P300S), and then cut into a sheet measuring 90 mm * 90 mm.

[0283] - Uniaxial stretching was performed using a polyethylene sheet with dimensions of 90 mm x 90 mm using KARO 5.0 equipment.

[0284] - Uniaxial stretching in the MD (machine direction) direction was performed after preheating for 60 seconds under each of the following conditions (Examples 1 to 5 and Comparative Examples 1 to 14: stretching after preheating for 60 seconds at 126 ℃, stretching 6 to 10 times at a stretching speed of 200 % / s, stretched film thickness of approximately 30 μm to approximately 40 μm based on 6 times stretching, and cooling by external discharge after staying in an annealing chamber (120 ℃) ​​for 5 seconds after stretching).

[0285] Evaluation of physical properties of stretched film

[0286] - Maximum Stretch Ratio: Measures the ratio of maximum stretching without film breakage when uniaxially stretched 6, 7.5, 9, or 10 times at a stretching speed of 200% / s according to the method described above.

[0287] - Shrinkage rate: A polyethylene composition sheet with dimensions of 90 mm x 90 mm (width x length) was uniaxially stretched 6 times in the MD direction to produce a film according to the method described above. After the film was cut to a width of 6 mm, a film shrinkage test was performed by heating it to 120 ℃ at a heating rate of 5 ℃ / min using a Dynamic Mechanical Analysis (DMA, DMA Q850) device from TA Instruments, and then leaving it at 120 ℃ for 1 hour (maintaining a stress of approximately 0.06 MPa). While performing the film shrinkage test, the change in length of the film in the MD direction was measured to calculate the shrinkage rate. Specifically, based on the initial length (A, unit mm) of the 6x uniaxially stretched film before heating, the shrinkage rate was calculated as a percentage of the difference between the initial film length (A, unit mm) and the film length (B, unit mm) after the film shrinkage test. That is, the shrinkage rate (%) of the stretched film is expressed as = [(AB) / A] x 100.

[0288] Maximum Stretch Shrinkage Rate (%) Example 1 103.56 Example 2 103.21 Example 3 103.30 Example 4 92.41 Example 5 93.08 Comparative Example 1 7.54.12 Comparative Example 2 7.54.50 Comparative Example 3 7.54.33 Comparative Example 4 7.54.42 Comparative Example 5 66.32 Comparative Example 6 7.55.20 Comparative Example 7 7.54.15 Comparative Example 8 64.66 Comparative Example 9 65.90 Comparative Example 107.56.10 Comparative Example 1162.40 Comparative Example 1296.50 Comparative Example 137.53.90 Comparative Example 147.54.29

[0289]

[0290] According to the results in Table 4 above, when the relative ratio of crystal fraction peak areas eluted according to temperature (°C) was measured by CEF analysis, the polyethylene compositions of Examples 1 to 5, in which the high-crystal content and low-crystal content were controlled to appropriate levels, were able to obtain films with excellent stretchability and excellent heat resistance of the final film. In particular, it was confirmed that the polyethylene compositions of Examples 1 to 5 exhibited excellent performance with a shrinkage rate of less than 4% even when the actual stretching ratio exceeded 9 times. This is expected to be because the high high-crystal content prevents easy deformation and maintains the shape even at high stretching ratios, thereby reducing the shrinkage rate. Furthermore, by including a certain level of low-crystal content, the degradation of processability caused by high crystallinity was prevented, and high stretchability was achieved.

[0291] However, it was confirmed that the polyethylene compositions of Comparative Examples 1 to 10 had film elongation ratios of only 6 or 7.5, resulting in poor stretchability and processability; furthermore, the film shrinkage rate increased from 4.12% to 6.10%, and heat resistance was significantly reduced. Additionally, while the polyethylene compositions of Comparative Examples 11, 13, and 14 improved the film shrinkage rate, their film elongation ratios were only 6, 7.5, and 7.5, respectively, indicating a significant decrease in stretchability and processability. Moreover, the polyethylene composition of Comparative Example 12 showed inferior results in terms of shrinkage rate.

[0292] Thus, the polyethylene composition of the present invention can effectively produce a stretched film having excellent stretch stability and excellent heat resistance. By maintaining appropriate tension in the stretching process area when manufacturing the stretched film, it is highly advantageous for the commercialization of products such as single-material packaging films that possess high shrinkage resistance, printability, and transparency, with excellent stretchability and productivity.

Claims

1. When the relative ratio of the peak areas of the crystallization fraction eluted according to temperature (°C) was measured using the crystallization elution fractionation (CEF) analysis method, The ratio of the peak area of ​​the low-crystallinity fraction eluted at 70°C or higher and 95°C or lower to the total peak area (CEF ≤95℃≥70℃ ) is 10% or more and 25% or less, and The ratio of the peak area of ​​the highly crystalline fraction eluted at 100 ℃ or higher to the total peak area (CEF ≥100℃ ) is 6% or more and 15% or less, and The ratio of the peak areas of the above low-crystallinity fraction (CEF) ≤95℃≥70℃ The ratio of the peak area of ​​the highly crystalline fraction (CEF) to the above (CEF) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) is 0.24 or greater, and Density is 0.940 g / cm³ 3 Above 0.970 g / cm³ 3 Lee Ha-in, Polyethylene composition.

2. In Paragraph 1, The ratio of the peak areas of the above low-crystallinity fraction (CEF) ≤95℃≥70℃ The ratio of the peak area of ​​the highly crystalline fraction (CEF) to the above (CEF) ≥100℃ The ratio of ) (CEF ≥100℃ / CEF ≤95℃≥70℃ ) is 0.24 or greater and 1.50 or less, Polyethylene composition.

3. In Paragraph 1, Melt Index (MI) 2.16 , 190 ℃, 2.16 kg) having 0.5 g / 10 min or more and 3.0 g / 10 min or less, Polyethylene composition.

4. In Paragraph 1, The weight-average molecular weight (Mw) is 80,000 g / mol or more and 160,000 g / mol or less, and molecular weight distribution (Mw / Mn) of 4 or more and 15 or less, Polyethylene composition.

5. In Paragraph 1, With a degree of crystallinity (Xc) of 65% or more and 95% or less, Polyethylene composition.

6. In Paragraph 1, The melting point (Tm) is 128 ℃ or higher and 136 ℃ or lower, and A crystallization temperature (Tc) of 116 ℃ or higher and 123 ℃ or lower, Polyethylene composition.

7. In Paragraph 1, The above polyethylene composition comprises one or more ethylene-alpha-olefin copolymers, Polyethylene composition.

8. In Paragraph 7, The above ethylene-alpha-olefin copolymer comprises, together with ethylene, one or more selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof, one or more alpha-olefins selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof. Polyethylene composition.

9. A stretched film comprising the polyethylene composition of claim 1.

10. In Paragraph 9. A polyethylene composition sheet with dimensions of 90 mm * 90 mm and a thickness of 200 μm, when uniaxially stretched at a stretching rate of 200% / s after preheating at 126 ℃ for 60 seconds, having a maximum elongation ratio of 8 or more, Continuous film.

11. In Paragraph 9. When a film shrinkage test was performed on the above-mentioned stretched film using a Dynamic Mechanical Analysis (DMA) device, which involves heating to 120°C at a heating rate of 5°C / min and then leaving it for 1 hour, A film in which the shrinkage rate (%, [(AB) / A] x 100), expressed as a percentage of the difference between the initial film length (A, unit mm) measured before the above film shrinkage test and the film length (B, unit mm) after performing the film shrinkage test, is 4% or less Continuous film.

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