KR20220041669A - Polyethylene and method for preparing the same - Google Patents

Abstract

The present invention relates to polyethylene and a method for preparing the same, and more specifically, relates to a polyethylene having a narrow molecular weight distribution to exhibit excellent tensile strength, having an appropriate range of melting temperature to ensure a low amount of dust, and having a high density; and a method for preparing the same.

Description

Polyethylene and its manufacturing method

The present invention relates to polyethylene and a method for preparing the same. More specifically, it relates to a polyethylene having a narrow molecular weight distribution, exhibiting excellent tensile strength, having a melting temperature in an appropriate range, a low amount of dust, and a high density, and a method for manufacturing the same.

Olefin polymerization catalyst systems can be classified into Ziegler-Natta and metallocene catalyst systems, and these two highly active catalyst systems have been developed according to their respective characteristics. Ziegler-Natta catalyst has been widely applied to existing commercial processes since its invention in the 1950s. There is a problem in that there is a limit in securing desired properties because the distribution is not uniform.

On the other hand, a metallocene catalyst is composed of a combination of a main catalyst containing a transition metal compound as a main component and a cocatalyst containing an organometallic compound containing aluminum as a main component. Such a catalyst is a homogeneous complex catalyst and is a single site catalyst. , and has a narrow molecular weight distribution according to the single active point characteristic, and a polymer with a uniform composition distribution of comonomers is obtained.

On the other hand, polypropylene resin used as a non-woven material has excellent chemical resistance and tensile strength and was mainly used as a surface material for hygiene products such as diapers and sanitary napkins. Len solubility is low, and there is a disadvantage in that the surface is rough when manufacturing a nonwoven fabric.

In order to improve the texture of the surface, polypropylene resin was mixed with a polyethylene resin, and a bicomponent fiber using polypropylene resin for the inside and polyethylene resin for the outside was produced to improve the feel and softness and used as a nonwoven material. . In addition, in order to provide convenience to users by improving the feel and ductility of the non-woven fabric, there is a trend to reduce the thickness of the spun yarn used.

Accordingly, it is further required to develop polyethylene with a narrow molecular weight distribution and reduced dust generation in order to secure excellent tensile strength and ductility when manufacturing polyethylene used for the bicomponent fiber.

An object of the present invention is to provide a polyethylene having a narrow molecular weight distribution, showing excellent tensile strength, having a melting temperature in an appropriate range, a small amount of dust, and a high density, and a method for manufacturing the same.

In order to solve the above problems, the present invention provides the following polyethylene:

Melt index (MFR _2.16 ) measured by ASTM D1238 under a load of 2.16 kg at 190 ° C. is 15 g/10 min or more and 30 g/10 min or less,

Melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ) measured by ASTM D1238 at 190 ° C is 2 or more and 3 or less,

Molecular weight distribution (MWD, Mw / Mn) is 1 or more and 3 or less,

Melting temperature (Tm) is 129 ℃ or more and 135 ℃ or less,

polyethylene.

In addition, the present invention is a transition metal compound represented by the following formula (1); And in the presence of a single supported catalyst comprising a carrier on which the transition metal compound is supported, it provides a method for producing the polyethylene, comprising the step of polymerizing an olefinic monomer:

[Formula 1]

In Formula 1,

M is a Group 4 transition metal,

Cp ₁ and Cp ₂ are each independently any one ring compound selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl and fluorenyl, One or more hydrogens of the ring compound are each independently C _1-20 alkyl, C _1-20 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl may be substituted with any one of the substituents,

Z ₁ and Z ₂ are each independently halogen, C _1-20 alkyl, C _2-10 alkenyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl.

Polyethylene according to the present invention has a narrow molecular weight distribution, exhibits excellent tensile strength, has a melting temperature in an appropriate range, produces little dust, and has a high density, so that it can be usefully applied for manufacturing purposes such as nonwoven fabrics requiring these properties.

The terminology used herein is used to describe exemplary embodiments only, and is not intended to limit the invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprises", "comprising" or "have" are intended to designate the presence of an embodied feature, step, element, or a combination thereof, but one or more other features or steps; It should be understood that the possibility of the presence or addition of components, or combinations thereof, is not precluded in advance.

Since the invention can have various changes and can have various forms, specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the invention.

Hereinafter, the present invention will be described in detail.

According to one embodiment of the invention,

Melt index (MFR _2.16 ) measured by ASTM D1238 under a load of 2.16 kg at 190 ° C. is 15 g/10 min or more and 30 g/10 min or less,

Melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ) measured by ASTM D1238 at 190 ° C is 2 or more and 3 or less,

Molecular weight distribution (MWD, Mw / Mn) is 1 or more and 3 or less,

Melting temperature (Tm) is 129 ℃ or more and 135 ℃ or less,

Polyethylene is provided.

Polyethylene according to an embodiment of the present invention has a melt index (MFR _2.16 ) of 15 g/10 min or more and 30 g/10 min or less as measured by ASTM D1238 under a load of 2.16 kg at 190 ° C.

Preferably, the melt index (MFR _2.16 ) measured by ASTM D1238 under a load of 2.16 kg at 190 ° C. is 16 g/10 min or more, 17 g/10 min or more, or 18 g/10 min or more, 27 g/10 min or less, 25 g/10 min or less, 23 g/10 min or less, 21 g/10 min or less, or 20 g/10 min or less. When the melt index is less than 15 g/10 min, extrusion and injection are difficult, so that it is impossible to produce a thin spun yarn form, and when the melt index exceeds 30 g/10 min There is a difficult problem.

Polyethylene according to an embodiment of the present invention has a melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ) of 2 or more and 3 or less measured at 190 ° C according to ASTM D1238.

The melt flow rate ratio is the melt flow index (MFR ₅ ) measured under 190 ° C. and 5 kg load for the polyethylene divided by the melt flow index measured under 190 ° C. and 2.16 kg load (MFR _2.16 ) according to ASTM D1238 am.

Preferably, the melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ) measured by ASTM D1238 at 190 ° C. is 2.1 or more, 2.2 or more, 2.3 or more, 2.4 or more, or 2.5 or more, and 2.9 or less, 2.8 or less, or 2.7 or less. By having the range of the melt flow rate ratio as described above, the flow property at each load is appropriately controlled, so that processability and mechanical properties can be improved at the same time.

Polyethylene according to an embodiment of the present invention has a molecular weight distribution (MWD, Mw/Mn) of 1 or more and 3 or less.

Preferably, the molecular weight distribution may be 1.5 or more, 1.8 or more, 2.0 or more, 2.3 or more, or 2.5 or more, and may be 2.9 or less, or 2.8 or less. Since the polyethylene of the present invention has a narrow molecular weight distribution as described above, molecules having similar sizes are advantageously aligned, and thus the draw ratio tends to increase. Due to this, it is easy to manufacture a thin spun yarn, and it can also have excellent tensile strength and ductility.

In the present invention, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight distribution are determined by measuring the weight average molecular weight (Mw) and the number average molecular weight (Mn) of polyethylene using gel permeation chromatography (GPC), respectively. and calculates the ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight as the molecular weight distribution.

Specifically, samples of polyethylene are evaluated using an Agilent PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300 mm length column. The evaluation temperature is 160° C., 1,2,4-trichlorobenzene is used as a solvent, and the flow rate is measured at a rate of 1 mL/min. Each polyethylene sample was pretreated by dissolving it in trichlorobenzene (1,2,4-Trichlorobenzene) containing 0.0125% BHT at 160 °C for 10 hours using a GPC analysis device (PL-GP220), and the concentration of 10 mg/10mL , and then supply in an amount of 200 μL. The values of Mw and Mn are determined using a calibration curve formed using polystyrene standards. The molecular weight of the polystyrene standard specimen is 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 9 types of 10,000,000 g/mol are used.

Polyethylene according to an embodiment of the present invention has a melting temperature (Tm) of 129 °C or more and 135 °C or less.

Preferably, the melting temperature may be 129 °C or more and 134 °C or less, 129 °C or more and 133 °C or less, or 129 °C or more and 132 °C or less. Since polyethylene satisfying the above melting temperature range has a relatively low melting temperature and exists in a molten state even in the process of cooling the extrudate, the uneven surface is filled with the low melting point polymer, making the surface of the extrudate smooth and excellent in ductility The amount of dust generated during or after processing may decrease as the number of gels formed on the surface decreases. In particular, in a nonwoven fabric made of a two-component mixed spun yarn composed of polypropylene and polyethylene, the lower the melting temperature of polyethylene, the better the interfacial adhesion between the two materials, and thus the amount of dust generated can be reduced.

The melting temperature is measured using a differential scanning calorimeter (Differential Scanning Calorimeter, DSC, device name: Q20, manufacturer: TA instruments). Specifically, the polyolefin is heated to 190°C and maintained for 5 minutes, and then the temperature is lowered to 50°C and then the temperature is increased again. At this time, the rate of rise and fall of the temperature is controlled at 10 °C/min, respectively. The melting temperature is the maximum point of the endothermic peak measured in the section where the second temperature rises.

Polyethylene according to an embodiment of the present invention may be high density polyethylene (HDPE) having a density of 0.940 g/cm ³ or more and 0.965 g/cm ³ or less as measured by ISO 1183-2 at 23 ° C. there is.

Preferably, the density is 0.945 g/cm ³ or more, 0.950 g/cm ³ or more, or 0.955 g/cm ³ or more, and may be 0.960 g/cm ³ or less.

The polyethylene of the present invention satisfying the above physical properties has a tensile strength of 26 MPa or more and 35 MPa or less, measured at a rate of 50 mm/min according to ASTM D638. Preferably, the tensile strength may be 26.5 MPa or more, 33 MPa or less, 31 MPa or less, or 30 MPa or less.

Polyethylene has excellent tensile strength and can be preferably used for nonwoven fabrics and the like.

In addition, when the polyethylene according to an embodiment of the present invention is manufactured as a nonwoven fabric, it has excellent tactile properties. The texture of the nonwoven fabric can be measured through a blind panel evaluation of 10 people. If more than 8 people rate the softness of the nonwoven fabric, it can be judged as 'excellent', if it is 6-7 people, it's 'excellent', if it's 4-5 people, it's 'normal', and if there are 3 people or less, it can be judged as 'poor'. .

On the other hand, the polyethylene of one embodiment is 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene , 1-octadecene, 1-eicosene, and one or more comonomers selected from the group consisting of mixtures thereof, preferably, may include 1-butene as a comonomer. By including the comonomer, the density of polyethylene may be lowered to improve the draw ratio and ductility.

According to another embodiment of the present invention, the polyethylene according to the present invention is a transition metal compound represented by the following formula (1); and polymerizing an olefinic monomer in the presence of a single supported catalyst comprising a carrier on which the transition metal compound is supported, wherein hydrogen is added at an amount of 0.1 g/hr or more and 3 g/hr or less, the step The reaction temperature of can be prepared according to a manufacturing method of 50 ℃ or more and 100 ℃ or less.

[Formula 1]

In Formula 1,

M is a group 4 transition metal,

Cp ₁ and Cp ₂ are each independently any one ring compound selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl and fluorenyl, One or more hydrogens of the ring compound are each independently C _1-20 alkyl, C _1-20 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl may be substituted with any one of the substituents,

Z ₁ and Z ₂ are each independently halogen, C _1-20 alkyl, C _2-10 alkenyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl.

In the transition metal compound included in the single supported catalyst according to the embodiment, the substituents of Formula 1 will be described in more detail as follows.

The halogen may be fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

C _1-20 alkyl may be straight chain, branched chain or cyclic alkyl. Specifically, C _1-20 alkyl is C _1-20 straight chain alkyl; C _1-10 straight chain alkyl; C _1-5 straight chain alkyl; C _3-20 branched or cyclic alkyl; C _3-15 branched or cyclic alkyl; or C _3-10 branched chain or cyclic alkyl. More specifically, C _1-20 alkyl may be methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl or cyclohexyl, and the like.

C _2-20 Alkenyl can be straight-chain, branched-chain or cyclic alkenyl. Specifically, C _2-20 alkenyl is C _2-20 straight chain alkenyl, C _2-10 straight chain alkenyl, C _2-5 straight chain alkenyl, C _3-20 branched chain alkenyl, C _3-15 branched chain alkenyl kenyl, C _3-10 branched chain alkenyl, C _5-20 cyclic alkenyl or C _5-10 cyclic alkenyl. More specifically, C _2-20 alkenyl may be ethenyl, propenyl, butenyl, pentenyl or cyclohexenyl, and the like.

C _6-20 aryl may mean a monocyclic, bicyclic or tricyclic aromatic hydrocarbon. Specifically, C _6-20 aryl may be phenyl, naphthyl or anthracenyl.

C _7-20 Alkylaryl may mean a substituent in which one or more hydrogens of aryl are substituted with alkyl. Specifically, C _7-20 alkylaryl may be methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl or cyclohexylphenyl.

C _7-20 Arylalkyl may mean a substituent in which one or more hydrogens of the alkyl are substituted by aryl. Specifically, C _7-20 Arylalkyl may be benzyl, phenylpropyl or phenylhexyl and the like.

C _1-20 Alkoxy may be straight-chain, branched-chain or cyclic alkoxy. Specifically, C _1-20 alkoxy may include, but is not limited to, methoxy, ethoxy, n-butoxy, tert-butoxy, phenyloxy, cyclohexyloxy, and the like.

C _2-20 alkoxyalkyl may mean a substituent in which one or more hydrogens of alkyl are substituted by alkoxy. Specifically, as C _2-20 alkoxyalkyl, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, butoxymethyl, butoxyethyl, butoxypropyl, butoxybutyl, butoxyheptyl, butoxy and hexyl, but is not limited thereto.

Preferably, Cp ₁ and Cp ₂ are each independently cyclopentadienyl, indenyl, or fluorenyl, wherein one or more hydrogens of cyclopentadienyl, indenyl, or fluorenyl are each independently C _{1 -20} alkyl, C _2-20 It may be substituted with any one of alkenyl, C _1-20 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl.

More preferably, Cp ₁ and Cp ₂ are each independently cyclopentadienyl, indenyl, or fluorenyl, and Cp ₁ and Cp ₂ are each independently unsubstituted or methyl, isopropyl, butyl, It may be substituted with 1 to 4 substituents selected from the group consisting of tertbutyl, phenylpropyl, hexyl, tertbutoxypentyl, tertbutoxyhexyl, phenyl and 3-butenyl.

Preferably, Z ₁ and Z ₂ may each independently be halogen, and more preferably, Z ₁ and Z ₂ may each independently be chlorine (Cl).

Preferably, the transition metal compound represented by Formula 1 may be any one selected from the group consisting of, but is not limited thereto:

.

.

.

.

The transition metal compound may be synthesized by applying known reactions, and more detailed synthesis methods may be referred to Examples.

Meanwhile, as the carrier, a carrier containing a hydroxyl group or a siloxane group on the surface may be used. Specifically, as the carrier, a carrier containing a hydroxyl group or a siloxane group having high reactivity by drying at a high temperature to remove moisture from the surface may be used. More specifically, the carrier may include any one or more mixtures selected from the group consisting of silica, alumina and magnesia. The carrier may be dried at a high temperature, and they typically include oxides, carbonates, sulfates, and nitrates such as Na ₂ O, K ₂ CO ₃ , BaSO ₄ and Mg(NO ₃ ) ₂ .

The drying temperature of the carrier is preferably 40 to 800 °C, more preferably 100 to 600 °C, and most preferably 100 to 300 °C. When the drying temperature of the carrier is less than 40 ℃, there is too much moisture, so that the surface moisture and the cocatalyst react. It disappears and only the siloxane remains, which is not preferable because the reaction site with the promoter decreases.

The amount of hydroxyl groups on the surface of the carrier is preferably 0.1 to 10 mmol/g, more preferably 0.5 to 5 mmol/g. The amount of hydroxyl groups on the surface of the carrier can be controlled by the method and conditions or drying conditions of the carrier, such as temperature, time, vacuum or spray drying, and the like.

If the amount of the hydroxyl group is less than 0.1 mmol/g, there are few reaction sites with the co-catalyst, and if it exceeds 10 mmol/g, it is not preferable because it may be caused by moisture other than the hydroxyl group present on the surface of the carrier particle. not.

The single supported catalyst according to the embodiment may further include a co-catalyst to activate the transition metal compound, which is a catalyst precursor. The cocatalyst is not particularly limited as long as it is an organometallic compound containing a Group 13 metal, and can be used when polymerizing olefins under a general metallocene catalyst. Specifically, the cocatalyst may be at least one compound selected from the group consisting of compounds represented by the following Chemical Formulas 2 to 4.

[Formula 2]

R ₆ -[Al(R ₅ )-O] _n -R ₇

In Formula 2,

R ₅ , R ₆ and R ₇ are each independently hydrogen, halogen, a C _1-20 hydrocarbyl group, or a halogen-substituted C _1-20 hydrocarbyl group,

n is an integer greater than or equal to 2,

[Formula 3]

D(R ₈ ) ₃

In Formula 2,

D is aluminum or boron,

R ₈ is each independently a halogen, a C _1-20 hydrocarbyl group, a C _1-20 hydrocarbyloxy group, or a halogen-substituted C _1-20 hydrocarbyl group,

[Formula 4]

[LH] ⁺ [W(A) ₄ ] ^- or [L] ⁺ [W(A) ₄ ] ^-

In Formula 4,

L is a neutral or cationic Lewis base,

H is a hydrogen atom,

W is a group 13 element,

A is each independently a C _1-20 hydrocarbyl group; C _1-20 hydrocarbyloxy group; and one or more of the substituents in which at least one hydrogen atom of these substituents is substituted with at least one of halogen, a C _1-20 hydrocarbyloxy group and a C _1-20 hydrocarbyl (oxy)silyl group.

Unless otherwise limited herein, the following terms may be defined as follows.

The hydrocarbyl group is a monovalent functional group in which a hydrogen atom is removed from hydrocarbon, and is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an aralkenyl group, an aralkynyl group, an alkylaryl group, an alkenylaryl group, and an alkyl group. It may include a nylaryl group and the like. 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 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, and a n-hexyl group. , a straight-chain, branched-chain or cyclic alkyl group such as n-heptyl group and cyclohexyl group; Or it may be an aryl group such as a phenyl group, a naphthyl group, or an anthracenyl group.

The hydrocarbyloxy group is a functional group in which a hydrocarbyl group is bonded to oxygen. Specifically, the hydrocarbyloxy group having 1 to 20 carbon atoms may be a hydrocarbyloxy group having 1 to 15 carbon atoms or 1 to 10 carbon atoms. More specifically, the hydrocarbyloxy group having 1 to 20 carbon atoms is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, tert-butoxy group, n-pentoxy group , a straight-chain, branched-chain or cyclic alkoxy group such as n-hexoxy group, n-heptoxy group, cyclohexoxy group; Alternatively, it may be an aryloxy group such as a phenoxy group or a naphthalenoxy group.

The hydrocarbyl(oxy)silyl group is a functional group in which 1 to 3 hydrogens of -SiH ₃ are substituted with 1 to 3 hydrocarbyl groups or hydrocarbyloxy groups. Specifically, the hydrocarbyl (oxy)silyl group having 1 to 20 carbon atoms may be a hydrocarbyl (oxy)silyl group having 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms. More specifically, the hydrocarbyl (oxy)silyl group having 1 to 20 carbon atoms is an alkyl group such as a methylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a dimethylethylsilyl group, a diethylmethylsilyl group, and a dimethylpropylsilyl group. silyl group; alkoxysilyl groups such as a methoxysilyl group, a dimethoxysilyl group, a trimethoxysilyl group and a dimethoxyethoxysilyl group; It may be an alkoxyalkylsilyl group such as a methoxydimethylsilyl group, a diethoxymethylsilyl group, and a dimethoxypropylsilyl group.

Non-limiting examples of the compound represented by Formula 2 may include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, or tert-butylaluminoxane. And, non-limiting examples of the compound represented by Formula 3 include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-sec-butylaluminum, Tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyl dimethyl aluminum, methyldiethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide or dimethyl aluminum Toxide etc. are mentioned. Finally, non-limiting examples of the compound represented by Formula 4 include trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis( Pentafluorophenyl) borate, N,N-dimethylanilinium n-butyltris(pentafluorophenyl)borate, N,N-dimethylanilinium benzyltris(pentafluorophenyl)borate, N,N-dimethylanilinium Tetrakis(4-(t-butyldimethylsilyl)-2,3,5,6-tetrafluorophenyl)borate, N,N-dimethylanilinium tetrakis(4-(triisopropylsilyl)-2,3 ,5,6-tetrafluorophenyl)borate, N,N-dimethylanilinium pentafluorophenoxytris(pentafluorophenyl)borate, N,N-dimethyl-2,4,6-trimethylanilinium tetrakis (pentafluorophenyl) borate, trimethylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N,N-dimethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) ) borate, hexadecyldimethylammonium tetrakis(pentafluorophenyl)borate, N-methyl-N-dodecylanilinium tetrakis(pentafluorophenyl)borate or methyldi(dodecyl)ammonium tetrakis(pentafluoro phenyl) borate and the like.

The amount of the co-catalyst used may be appropriately adjusted according to the desired physical properties or effects of a single supported catalyst.

A single supported catalyst according to the embodiment may include, for example, supporting a cocatalyst on the support; and supporting the transition metal compound, which is a catalyst precursor, on a promoter supported carrier.

Specifically, in the step of supporting the cocatalyst on the carrier, the cocatalyst may be added to the carrier dried at a high temperature, and stirred at a temperature of about 20 to 120° C. to prepare a carrier supported on the cocatalyst.

In addition, in the step of supporting the catalyst precursor on the promoter supported carrier, the transition metal compound is added to the promoter supported carrier obtained in the step of supporting the promoter on the support, and again stirred at a temperature of about 20 to 120 ° C. A supported catalyst can be prepared.

In the step of supporting the catalyst precursor on the cocatalyst carrier, the transition metal compound is added to the cocatalyst carrier and stirred, and then a cocatalyst may be further added to prepare a supported catalyst.

The content of the carrier, the cocatalyst, the cocatalyst supported carrier and the transition metal compound used in the single supported catalyst according to the embodiment may be appropriately adjusted according to the desired physical properties or effects of the supported catalyst.

In this case, the loading amount of the transition metal compound supported on the carrier by the above step may be 0.01 to 1 mmol/g based on 1 g of the carrier. That is, it is preferable to control so as to fall within the above-described supported amount range in consideration of the contribution effect of the catalyst by the transition metal compound.

In preparing the single supported catalyst, the reaction solvent includes a hydrocarbon solvent such as pentane, hexane, heptane, and the like; Alternatively, an aromatic solvent such as benzene or toluene may be used.

For a specific method of preparing the supported catalyst, reference may be made to Examples to be described later. However, the preparation method of the supported catalyst is not limited to the content described herein, and the preparation method may additionally employ a step commonly employed in the technical field to which the present invention belongs, and the step of the preparation method ( ) may be modified by means of a routinely changeable step(s).

For the polymerization of polyethylene, various polymerization processes known as polymerization of polyethylene, such as a continuous solution polymerization process, a bulk polymerization process, a suspension polymerization process, a slurry polymerization process, an emulsion polymerization process, a gas phase polymerization process, may be employed.

Polymerization of the polyethylene may be carried out by reacting at a temperature of about 25 to about 500 °C and a reaction pressure of about 1 to about 100 kgf/cm ² for about 1 to about 24 hours. Specifically, the polymerization of the polyethylene may be carried out at a temperature of about 25 to about 500 °C, preferably about 25 to about 200 °C, more preferably about 50 to about 100 °C. In addition, the reaction pressure may be from about 1 to about 100 kgf/cm ² , preferably from about 1 to about 60 kgf/cm ² , more preferably from about 5 to about 45 kgf/cm ² .

Preferably, in the method for producing polyethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1 - may include one or more comonomers selected from the group consisting of -tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, and mixtures thereof, but preferably, 1-butene is used as a comonomer can be included as By including the comonomer, the density of polyethylene may be lowered to improve the draw ratio and ductility.

Preferably, the content of 1-butene in the polyethylene production method may be included in an amount of 0.5 parts by weight or more and 2.0 parts by weight or less, or 1.2 parts by weight or more and 1.5 parts by weight or less, based on 100 parts by weight of ethylene. When the above range is satisfied, the density of polyethylene may be lowered to achieve improvement in draw ratio and ductility.

In addition, in the polymerization reaction, the single supported catalyst may be used in a dissolved or diluted state in a solvent such as pentane, hexane, heptane, nonane, decane, toluene, benzene, dichloromethane, chlorobenzene, and the like. In this case, by treating the solvent with a small amount of alkylaluminum or the like, a small amount of water or air that may adversely affect the catalyst may be removed in advance.

In addition, if necessary, the slurry polymerization may be performed under hydrogenation or non-hydrogenation conditions.

Polyethylene obtained according to the manufacturing method of one embodiment has a narrow molecular weight distribution, so it is easy to extrude into a thin spun yarn, exhibits excellent tensile strength, has a melting temperature in an appropriate range, generates less dust, and has a high density. It can be preferably used for manufacturing purposes such as nonwoven fabrics requiring properties.

Hereinafter, it will be described in more detail to help the understanding of the present invention. However, the following examples only illustrate the present invention, and the content of the present invention is not limited by the following examples.

[Preparation of transition metal compound]

Synthesis Example 1: [tBu-O-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ manufacture of

t-Butyl-O-(CH ₂ ) ₆ -Cl was prepared by the method presented in the literature (Tetrahedron Lett. 2951 (1988)) using 6-chlorohexanol, and NaCp was reacted with it t-Butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ was obtained (yield 60%, bp 80 ℃ / 0.1 mmHg).

In addition, t-Butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ was dissolved in THF at -78 °C, n-butyllithium (n-BuLi) was slowly added thereto, and then heated to room temperature, followed by reaction for 8 hours. . The solution was again slowly added to a suspension solution of ZrCl ₄ (THF) ₂ (1.70 g, 4.50 mmol)/THF (30 mL) at -78 ° C., and the lithium salt solution was slowly added to room temperature. was further reacted for 6 hours.

All volatile substances were vacuum-dried, and a hexane solvent was added to the obtained oily liquid substance and filtered. After vacuum drying the filtered solution, hexane was added to induce a precipitate at low temperature (-20 °C). The obtained precipitate was filtered at low temperature to obtain a white solid [tBu-O-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ compound (yield 92%).

¹ H NMR (300 MHz, CDCl ₃ ): 6.28 (t, J = 2.6 Hz, 2 H), 6.19 (t, J = 2.6 Hz, 2 H), 3.31 (t, 6.6 Hz, 2 H), 2.62 ( t, J = 8 Hz), 1.7 - 1.3 (m, 8 H), 1.17 (s, 9 H).

¹³ C NMR (CDCl ₃ ): 135.09, 116.66, 112.28, 72.42, 61.52, 30.66, 30.61, 30.14, 29.18, 27.58, 26.00.

Comparative Synthesis Example 1: (tBu-O-(CH ₂ ) ₆ )(CH ₃ )Si(C ₅ (CH ₃ ) ₄ )(tBu-N)TiCl ₂ manufacture of

After adding 50 g of Mg(s) to a 10 L reactor at room temperature, 300 mL of THF was added. After adding about 0.5 g of I ₂ , the temperature of the reactor was maintained at 50 °C. After the reactor temperature was stabilized, 250 g of 6-t-butoxyhexyl chloride was added to the reactor at a rate of 5 mL/min using a feeding pump. As 6-t-butoxyhexyl chloride was added, it was observed that the reactor temperature increased by about 4 to 5°C. The mixture was stirred for 12 hours while continuously adding 6-t-butoxyhexyl chloride. After 12 hours of reaction, a black reaction solution was obtained. After taking 2 mL of the resulting black solution, water was added to obtain an organic layer, and 6-t-butoxyhexane was identified through 1H-NMR. It was found that the Grignard reaction proceeded well from the 6-t-butoxyhexane. 6-t-butoxyhexyl magnesium chloride was synthesized by the above method.

After 500 g of MeSiCl ₃ and 1 L of THF were added to the reactor, the temperature of the reactor was cooled to -20 °C. 560 g of the synthesized 6-t-butoxyhexyl magnesium chloride was added to the reactor at a rate of 5 mL/min using a feeding pump. After feeding of the Grignard reagent was completed, the temperature of the reactor was slowly raised to room temperature and stirred for 12 hours. After 12 hours of reaction, it was confirmed that a white MgCl ₂ salt was formed. By adding 4 L of hexane, salt was removed through a labdori to obtain a filter solution. After adding the obtained filter solution to the reactor, hexane was removed at 70° C. to obtain a pale yellow liquid. It was confirmed that the obtained liquid was a desired methyl (6-t-butoxyhexyl) dichlorosilane {Methyl (6-t-butoxyhexyl) dichlorosilane} compound through 1H-NMR.

1H-NMR (CDCl ₃ ): 3.3 (t, 2H), 1.5 (m, 3H), 1.3 (m, 5H), 1.2 (s, 9H), 1.1 (m, 2H), 0.7 (s, 3H)

After adding tetramethylcyclopentadiene (1.2 mol, 150 g) and 2.4 L of THF to the reactor, the temperature of the reactor was cooled to -20 °C. n-BuLi was added to the reactor at a rate of 5 mL/min using a 480 mL feeding pump. After adding n-BuLi, the reactor was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours of reaction, an equivalent of methyl (6-t-butoxy hexyl) dichlorosilane (Methyl (6-t-butoxy hexyl) dichlorosilane, 326 g, 350 mL) was quickly added to the reactor. After stirring for 12 hours while slowly raising the temperature of the reactor to room temperature, the temperature of the reactor was cooled to 0 °C again, and 2 equivalents of t-BuNH ₂ was added thereto. The reactor was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours of reaction, THF was removed and 4 L of hexane was added to obtain a filter solution from which salt was removed through Labdory. After the filter solution was added to the reactor again, hexane was removed at 70° C. to obtain a yellow solution. It was confirmed that the obtained yellow solution was a methyl (6-t-butoxyhexyl) (tetramethylCpH)t-butylaminosilane (Methyl(6-t-butoxyhexyl)(tetramethylCpH)t-Butylaminosilane) compound through 1H-NMR. .

TiCl ₃ (THF) ₃ (10 mmol ) was added quickly. The reaction solution was stirred for 12 hours while slowly raising the temperature from -78 °C to room temperature. After stirring for 12 hours, an equivalent of PbCl ₂ (10 mmol) was added to the reaction solution at room temperature, followed by stirring for 12 hours. After stirring for 12 hours, a dark black solution with a bluish color was obtained. After removing THF from the resulting reaction solution, hexane was added to filter the product. After removing hexane from the obtained filter solution, it was confirmed from 1H-NMR that it was (tBu-O-(CH ₂ ) ₆ )(CH ₃ )Si(C ₅ (CH ₃ ) ₄ )(tBu-N)TiCl ₂ .

1H-NMR (CDCl ₃ ): 3.3 (s, 4H), 2.2 (s, 6H), 2.1 (s, 6H), 1.8 to 0.8 (m), 1.4 (s, 9H), 1.2 (s, 9H), 0.7 (s, 3H)

[Preparation of supported catalyst]

(Synthesis of supported catalyst)

All supported catalyst preparation processes were carried out in an inert atmosphere such as nitrogen or argon, and standard Schlenk technology and glove box technology were used. Toluene was used after purchasing Anhydrous Grade from Sigma-Aldrich, and then passing it through an activated molecular sieve (Molecular Sieve, 4A) or activated alumina layer to further dry it. MAO (methylaluminoxane) was purchased from Albemarle's 10% toluene solution (HS-MAO-10%), and Silica was dehydrated by applying Grace's SYLOPOL 952 at 600 °C for 12 hours under vacuum. used after As the borate compound, Trityl tetrakis(pentafluorophenyl)borate (Asahi) was purchased and used.

Preparation Example 1

After adding 4.0 kg of toluene to the autoclave reactor and 1 kg of prepared silica, the reactor was stirred while raising the temperature of the reactor to 95 °C. After the silica was sufficiently dispersed, 5.7 kg of a 10 wt% methylaluminoxane (MAO)/toluene solution was added, and the mixture was stirred at 95° C. at 200 rpm for 16 hours. After the temperature was lowered to 40 °C, the unreacted aluminum compound was removed by washing with a sufficient amount of toluene. Thereafter, after raising the temperature of the reactor to 80° C., 35.7 g of LiCl was dispersed in 100 ml of toluene, and the dispersion was introduced into the reactor. Next, 100 g of the metallocene compound of Synthesis Example 1 ([tBu-O-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ ) was dissolved in 200 mL of toluene to make a solution, and then added to the reactor It was stirred for 2 hours. Thereafter, the catalyst was cooled, the reactor temperature was lowered to room temperature, and the toluene layer was separated and removed, followed by replacement with hexane. After sinking the catalyst again, the hexane layer was separated and removed, and the remaining hexane was removed under reduced pressure to prepare a single supported catalyst.

Comparative Preparation Example 1

A supported catalyst was prepared in the same manner as in Supported Catalyst Preparation Example 1, but the metallocene compound to be added was prepared as follows. After dissolving 50 g of Synthesis Example 1 ([tBu-O-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ ) in 100 mL of toluene to make a solution, it was put into a reactor and stirred for 2 hours, Comparative Synthesis Example Dissolve 20 g of 1((tBu-O-(CH ₂ ) ₆ )(CH ₃ )Si(C ₅ (CH ₃ ) ₄ )(tBu-N)TiCl ₂ ) in 100 mL of toluene to make a solution, and then put it in the reactor. and stirred for 2 hours. Thereafter, a hybrid supported catalyst of Synthesis Example 1 and Comparative Synthesis Example 1 was prepared by removing toluene and hexane in the same manner as in Preparation Example 1.

Comparative Preparation Example 2

Comparative Synthesis Example 1 ((tBu-O-(CH ₂ ) ₆ )(CH ₃ )Si(C ₅ (CH ₃ ) ₄ )(tBu-N in which a hybrid supported catalyst was prepared in the same manner as in Comparative Preparation Example 1 ) The amount of TiCl ₂ ) was set to 40 g.

Comparative Preparation Example 3

Comparative Synthesis Example 1 ((tBu-O-(CH ₂ ) ₆ )(CH ₃ )Si(C ₅ (CH ₃ ) ₄ )(tBu-N in which a hybrid supported catalyst was prepared in the same manner as in Comparative Preparation Example 1 ) The amount of TiCl ₂ ) was 80 g.

[Production of polyethylene]

Example 1

The single supported catalyst prepared in Preparation Example 1 was put into a 220 L reactor of the pilot plant in a single slurry polymerization process to prepare high-density polyethylene according to a conventional method. Ethylene 10 kg/hr and hydrogen 0.8 g/hr were continuously reacted in a hexane slurry state at a reactor temperature of 80 °C. Here, as a comonomer, 5 mL/min of 1-butene was added. After the reaction, a high-density polyethylene in powder form was prepared through a solvent removal and drying process.

Example 2

In the same method as in Example 1, hydrogen was changed to 1.0 g/hr, and high-density polyethylene was prepared by a method without adding a comonomer.

Comparative Example 1

Polyethylene was prepared under the same conditions as in Example 1, except that the hybrid supported catalyst of Comparative Example 1 was used instead of the single supported catalyst.

Comparative Example 2

Polyethylene was prepared under the same conditions as in Example 1, except that the hybrid supported catalyst of Comparative Example 2 was used instead of the single supported catalyst.

Comparative Example 3

Polyethylene was prepared under the same conditions as in Example 1, except that the hybrid supported catalyst of Comparative Example 3 was used instead of the single supported catalyst.

Comparative Example 4

MK910 (SK Global Chemical) prepared using a Ziegler-Natta catalyst was used as polyethylene of Comparative Example 4.

Comparative Example 5

Aspun 6835 (Dow, Inc.) prepared using a Ziegler-Natta catalyst was used as the polyethylene of Comparative Example 5.

[Production of non-woven fabric]

For the polyethylene of the above examples and comparative examples, the literature [Report No. 4364 of the Naval Research Laboratories, published May 25, 1954 entitled "Manufacture of Superfine Organic Fibers" by Wente, Van. A. Boone, C. D., and Fluharty, E. L.], a nonwoven fabric was prepared by extruding the masterbatch pellets into a microfiber web.

Specifically, a masterbatch was prepared by mixing the polyethylene resin prepared above or the purchased polyethylene resin with Exolit® OP 950 additive (2.5 wt.%), and then pelletized using a 25 mm twin-screw extruder. Then, the melted masterbatch composition was fed to a melt pump (65 rpm) using a 31 mm Brabender conical twin screw extruder, followed by a 25 cm wide melt having outlets (10 outlets/cm) and an outlet diameter of 381 μm. It was fed to a blowing die. The melt temperature was 210 °C, the screw speed was 120 rpm, the die was held at 210 °C, the primary air temperature and pressure were 270 °C and 54 kPa (7.8 psi), respectively, and the polymer throughput rate was 5.2 kg/hr. , the collector/die distance was 15.0 cm. While the microfine fibers spun from the outlet fell to the collector, they were cooled with cooling air using two pumps, and the microfine fibers collected at the collector were used with upper and lower rolls to prepare a nonwoven fabric by a calendar process. At this time, the temperature of the cooling air was 16 °C, and the temperature of the upper/lower rolls during the calendar process was 160 °C/155 °C, respectively.

[Experimental example]

The physical properties of the polyethylene and nonwoven fabrics prepared in Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 1.

1) Evaluation of the physical properties of polyethylene

(1) Density (g/cm ³ ): Measured at 23° C. according to ISO 1183-2.

(2) Melt index (MFR _2.16 , g/10min): It was measured at 190° C. under a load of 2.16 kg according to ASTM D1238, and was expressed as the weight (g) of the polymer melted for 10 minutes.

(3) Melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ): The melt flow index (MFR ₅ ) measured under 190 ° C. and 5 kg load for the polyethylene according to ASTM D1238 was measured under 190 ° C. and 2.16 kg load. It is expressed as a value divided by the calculated melt flow index (MFR _2.16 ).

(4) Molecular weight distribution (MWD, Mw/Mn): As a gel permeation chromatography (GPC) apparatus, an Agilent PL-GPC220 instrument may be used, and a Polymer Laboratories PLgel MIX-B 300 mm long column may be used. At this time, the measurement temperature is 160 ℃, 1,2,4-trichlorobenzene (1,2,4-Trichlorobenzene) can be used as a solvent, and can be applied at a flow rate of 1 mL/min. Each polyethylene sample was pretreated by dissolving it in trichlorobenzene (1,2,4-Trichlorobenzene) containing 0.0125% BHT at 160°C for 10 hours using a GPC analysis device (PL-GP220), and a concentration of 10 mg/10mL After preparing it, it can be measured by supplying it in an amount of 200 μL. In addition, the values of Mw and Mn can be derived using a calibration curve formed using a polystyrene standard specimen. The weight average molecular weight of the polystyrene standard specimen is 2000 g/mol, 10000 g/mol, 30000 g/mol, 70000 g/mol, 200000 g/mol, 700000 g/mol, 2000000 g/mol, 4000000 g/mol, 10000000 g 9 types of /mol can be used

(5) Melting temperature (Tm, ℃): The melting temperature (Tm) of polyethylene was measured using a Differential Scanning Calorimeter (DSC, device name: Q20, manufacturer: TA instruments). Specifically, the polymer is heated to a temperature of 190°C and maintained at that temperature for 5 minutes, then lowered to 50°C, and then the temperature is increased again to melt the peak of the DSC (Differential Scanning Calorimeter, manufactured by TA instruments) curve. It was measured by temperature (Tm). In this case, the rate of rise and fall of the temperature was 10 °C/min, and the melting temperature (Tm) was measured in the section in which the second temperature rises and falls.

(6) Tensile strength: It was measured at a speed of 50 mm/min according to ASTM D638.

2) Evaluation of physical properties of nonwoven fabric

(1) The texture of the nonwoven fabric: The texture of the nonwoven fabric was measured through a blind panel evaluation of 10 people. If more than 8 people evaluated the softness of the nonwoven fabric, it was marked as 'very good', and if 6-7 people, it was 'excellent'. 'Excellent', 4-5 people, 'normal', and 3 or less, 'poor'.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 catalyst metallocene
single supported catalyst metallocene
single supported catalyst metallocene
hybrid supported catalyst metallocene
hybrid supported catalyst metallocene
hybrid supported catalyst Ziegler-
Nata
catalyst Ziegler-
Nata
catalyst density
(g/cm ³ ) 0.954 0.958 0.950 0.955 0.958 0.956 0.950 MFR _2.16 (g/10min) 19.5 18.2 14.8 12.2 6.5 19.6 17.5 MFRR (MI _5.12 /MI _2.16 ) 2.52 2.55 3.07 3.19 3.38 2.78 2.73 MWD (Mw/Mn) 2.48 2.62 3.51 4.89 5.65 3.02 2.97 T _m (℃) 129 130 131 133 134 133 128 Tensile strength (sheet, MPa) 27.4 29.7 39.8 46.4 80.3 25.5 24.2 Non-woven
tactile
(Panel test) So
Great Great commonly error error Great commonly

As shown in Table 1, it was confirmed that the polyethylene of the present invention had a high melt index and a narrow molecular weight distribution compared to that using a hybrid supported catalyst. In addition, the tensile strength was superior to that of polyethylene prepared using the Ziegler-Natta catalyst, and the prepared nonwoven fabric had excellent feel.

Claims (10)

Melt index (MFR _2.16 ) measured by ASTM D1238 under a load of 2.16 kg at 190 ° C. is 15 g/10 min or more and 30 g/10 min or less,
Melt flow rate ratio (MFRR, MFR ₅ /MFR _2.16 ) measured by ASTM D1238 at 190 ° C is 2 or more and 3 or less,
Molecular weight distribution (MWD, Mw / Mn) is 1 or more and 3 or less,
Melting temperature (Tm) is 129 ℃ or more and 135 ℃ or less,
polyethylene.
The method of claim 1,
Density measured according to ISO 1183-2 at 23 ° C is 0.940 g/cm ³ or more and 0.965 g/cm ³ or less,
polyethylene.
According to claim 1,
Tensile strength of 26 MPa or more and 35 MPa or less, measured at a speed of 50 mm/min according to ASTM D638
polyethylene.
According to claim 1,
The polyethylene comprises 1-butene as a comonomer,
polyethylene.
A transition metal compound represented by the following formula (1); and polymerizing an olefinic monomer in the presence of a single supported catalyst comprising a carrier on which the transition metal compound is supported,
In the above step, hydrogen is input at 0.1 g/hr or more and 3 g/hr or less,
The reaction temperature of the above step is 50 ℃ or more and 100 ℃ or less,
The method for producing the polyethylene of claim 1 :
[Formula 1]

In Formula 1,
M is a Group 4 transition metal,
Cp ₁ and Cp ₂ are each independently any one ring compound selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl and fluorenyl, One or more hydrogens of the ring compound are each independently C _1-20 alkyl, C _2-20 substituted with any one of alkenyl, C _1-20 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl;
Z ₁ and Z ₂ are each independently halogen, C _1-20 alkyl, C _2-10 alkenyl, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl.
6. The method of claim 5,
Cp ₁ and Cp ₂ are each independently cyclopentadienyl, indenyl, or fluorenyl,
The Cp ₁ and Cp ₂ are each independently unsubstituted, or a group consisting of methyl, isopropyl, butyl, tertbutyl, phenylpropyl, hexyl, tertbutoxypentyl, tertbutoxyhexyl, phenyl and 3-butenyl substituted with 1 to 4 substituents selected from,
A method for producing polyethylene.
6. The method of claim 5,
Z ₁ and Z ₂ are each independently halogen;
A method for producing polyethylene.
6. The method of claim 5,
The olefinic monomer comprises ethylene and 1-butene,
A method for producing polyethylene.
9. The method of claim 8,
The content of 1-butene is 0.5 parts by weight or more and 2.0 parts by weight or less relative to 100 parts by weight of ethylene,
A method for producing polyethylene.
6. The method of claim 5,
The transition metal compound represented by Formula 1 is any one selected from the group consisting of
Method for making polyethylene:

.

.