JP3375150B2 - Ethylene resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene resin composition having a very wide molecular weight distribution. More specifically, an ethylene / α-olefin copolymer, which is a high molecular weight component and has a very wide distribution of short chains between molecules, a relatively low molecular weight ethylene homopolymer or ethylene / α-olefin copolymer And an ethylene (co) polymer obtained by high-pressure radical polymerization, which has a good balance of physical properties such as melt elasticity, flow properties, and mechanical properties, and is particularly excellent in mechanical properties and optical properties at low temperatures. Composition. [0002] Conventional high-pressure low-density polyethylene (HP)
-LDPE), that is, low-density polyethylene obtained by radical polymerization of ethylene under high temperature and high pressure using a tube type or autoclave type reactor has a long chain branch length comparable to the main chain and 1 to 6 carbon atoms. Since the structure has a short-chain branch consisting of two alkyl groups, it has low crystallinity and is soft. Therefore, HP-LDPE has inferior mechanical properties such as resistance to environmental stress cracking, tensile impact value, dart impact value, and tear strength, particularly poor mechanical properties at low temperatures. On the other hand, linear low-density polyethylene (LL)
DPE) is an ethylene / α-olefin copolymer produced using various processes such as a gas phase method, a slurry method, a solution method, and a high-pressure ionic polymerization method, and various catalysts and polymerization conditions. -It has better mechanical properties than HP-LDPE because it has only short-chain branches that are uniquely determined by the type of olefin. However, since LLDPE generally has a very narrow molecular weight distribution, it is inferior in melt elasticity such as melt tension and flow characteristics such as N-value, flow parameter and critical shear rate. Defects related to melt elasticity and flow characteristics are mainly manifested in moldability, specifically, decrease in extrusion rate during molding, increase in extrusion pressure, increase in power consumption, poor high-speed moldability, surface roughness of molded products. -There are problems such as generation of fish eyes and heat deterioration due to heat generation in the extruder. [0004] When the molecular weight is reduced to improve the flow characteristics of LLDPE, there is a disadvantage that mechanical properties such as impact strength and environmental stress cracking resistance, particularly mechanical properties at low temperature and melt elasticity are remarkably reduced. Further, even if the density is reduced to improve the mechanical properties, the melt elasticity is hardly improved. As described above, it has been extremely difficult to simultaneously improve the mechanical properties of LLDPE, particularly the mechanical properties at low temperatures, the flow properties, and the melt elasticity in a well-balanced manner. Heretofore, there has been reported a method for widening the molecular weight distribution of an ethylene / α-olefin copolymer for the purpose of improving flow characteristics (for example, Japanese Patent Application Laid-Open No. 57-21409).
However, simply increasing the molecular weight distribution in this way, the melt elasticity and mechanical properties, especially at low temperatures, are not only improved, but rather significantly reduced. I do. Regarding the improvement of mechanical properties and flow properties, the degree of short-chain branching of high-molecular-weight components in ethylene / α-olefin copolymers composed of high-molecular-weight components and low-molecular-weight components was specified, and By introducing many chain branches, not only mechanical properties and fluidity but also environmental stress crack resistance (ESCR)
Have also been attempted (Japanese Patent Application Laid-Open No. 54-1004).
No. 44, Japanese Patent Publication No. Sho 64-7096). But,
Although the mechanical properties, especially at low temperatures, vary greatly depending on the distribution of short-chain branches of the high molecular weight components, the above method can be used to improve the mechanical properties and flow properties, especially at low temperatures. It is not satisfactory as a means of doing so. Furthermore, it is impossible to improve everything in good balance, including melt elasticity. SUMMARY OF THE INVENTION In view of the above problems, the present invention maintains physical properties such as heat resistance, ESCR, flexibility, etc., and has not yet solved melt elasticity, flow characteristics, mechanical properties, and the like. It is an object of the present invention to provide an ethylene-based resin composition having excellent properties, particularly excellent mechanical properties at low temperatures. The inventors of the present invention have conducted intensive studies in view of the above-mentioned objects, and as a result, have found that specific ethylene, which is a high molecular weight component and has a very wide distribution of short-chain branches between molecules, can be obtained. Melt elasticity and flow by blending α-olefin copolymer with relatively low molecular weight ethylene homopolymer or ethylene / α-olefin copolymer and ethylene (co) polymer by high pressure radical polymerization The present inventors have found that an ethylene-based resin composition having excellent properties and mechanical properties, particularly excellent mechanical properties and optical properties at low temperatures, and excellent processability can be obtained, and have reached the present invention. [0008] That is, the present invention provides (I) a method of supporting a solid carrier
Polymerized with a highly active Ziegler-type catalyst,
Ethylene satisfying (a) to (d) and α- having 3 to 18 carbon atoms.
5-92% by weight of copolymer with olefin, (a) intrinsic viscosity (η ₁ ) 1.2-9.0 dl / g, (b) density (d ₁ ) 0.890-0.940 g / cm ³ , (c) In the elution temperature-elution amount curve obtained by the continuous heating elution fractionation method, the ratio S (Ib / I) of the area Ib at an elution temperature of 25 to 90 ° C. to the area Ia under the elution temperature of 90 ° C. or more.
a) is calculated from the following equation: S ₁ or less; S ₁ = 20η ₁ ⁻¹ exp [−50 (d ₁ −0.900)] (d) Soluble content of orthodichlorobenzene at 25 ° C. W weight% is calculated from the following equation. that W ₁ or _{more, W 1 = 20exp (-η 1} ), (II) below (e) and copolymers of ethylene and having from 3 to 18 carbon atoms in the α- olefin which satisfies (f) five to ninety-two wt% (E) intrinsic viscosity (η ₂ ) 0.2 to 1.6 dl / g, (f) density (d ₂ ) 0.890 to 0.980 g / cm ³ , and (III) low density polyethylene, ethylene-vinyl Beauty treatment
Copolymer, ethylene-α, β-unsaturated carboxylic acid copolymer
Merging and ethylene-α, β-unsaturated carboxylic acid ester
At least one ethylene (co) polymer obtained by high-pressure radical polymerization of 3 to 50% by weight, and the total of the components (I), (II) and (III) is 100% by weight.
And a mixture satisfying the relationship of η ₁ > η ₂ , wherein the intrinsic viscosity of the mixture is 0.7 to 6.0 dl / g and the density is 0.89.
N−0 calculated from 0 to 0.950 g / cm ³ and the following equation 2.
The present invention provides an ethylene-based resin composition having a value of 1.7 to 3.5. [0009] Hereinafter, the contents of the present invention will be described in detail. The high molecular weight component or low molecular weight component ethylene / α-olefin copolymer of the present invention refers to ethylene and α-olefin having 3 to 18 carbon atoms.
Consisting of a copolymer with an olefin, particularly having 4 to 10 carbon atoms
Are preferred in terms of mechanical properties. Specifically, 1
-Butene, 1-pentene, 1-hexene, 4-methyl-
Examples thereof include 1-pentene, 1-octene, 1-nonene, 1-decene, and the like. Note that two or more α-olefins may be used in combination. The high molecular weight component (I) is supported on a solid carrier.
Et polymerized by Ziegler type catalyst having a lifting been highly active <br/> a styrene · alpha-olefin copolymer, (a) intrinsic viscosity (eta ₁₎ is 1.2~9.0dl / g, Preferably 1.4 to 8.5 d
l / g, more preferably in the range of 1.6 to 8.0 dl / g,
(b) Density (d ₁₎ is in the range of 0.890~0.940g / cm ^3, preferably in the range of 0.890~0.935g / cm ^3. When the intrinsic viscosity (η ₁ ) is less than 1.2 dl / g, the melt elasticity and the mechanical properties of the obtained composition are inferior, and when it exceeds 9.0 dl / g, the surface roughness of the molded product is poor. Formability such as generation of fish eyes is reduced. Further, those having a density (d ₁ ) of less than 0.890 g / cm ³ are not preferable because they are difficult to produce and cause stickiness of the obtained composition. On the other hand, when d ₁ exceeds 0.940 g / cm ³ , the melt elasticity and mechanical properties are undesirably reduced. A high branching component containing a large amount of short-chain branches dissolves in a solvent at a low temperature, while a low branching component having a small number of short chains does not dissolve in a solvent unless the temperature is high. It can be measured quantitatively. As shown in the above (c), the component (I) used in the present invention is a continuous temperature eluted fractionation method (Temperature Rising Elu-tion Fractionation (T
REF); Journal of Polymer Science: Polymer Physic
sEdition, Vol. 20, 441-455 (1982))
In the elution amount curve, it is necessary that a specific relationship be established between the area Ia under the elution temperature of 90 ° C or higher and the same area Ib at the elution temperature of 25 to 90 ° C. That is, the value of the area ratio S = Ib / Ia shown in the schematic diagram of FIG. 1, must be S ₁ or less obtained from the following equation. S ₁ = 20η ₁ ^-1 exp [−50 (d ₁ −0.900)] When the value of S exceeds S ₁ , the branch distribution becomes almost uniform, resulting in melt elasticity and mechanical properties, especially mechanical properties at low temperatures. The high branching degree component, which is extremely effective for the characteristics, is relatively undesirably reduced. (D) 25 ° C. of the component (I) used in the present invention
The orthodichlorobenzene-soluble component is a component having an extremely high branching distribution such that the elution temperature is too low to be quantified by the above-mentioned continuous heating elution fractionation method. is there. That is,
W% by weight must be W ₁ or more determined from the following equation. Preferably at W ₃ or more. W ₁ = 20 exp [−η ₁ ] W ₃ = 22 exp [−η ₁ ] When the value of W is less than W ₁ , the degree of branching is extremely effective for melt elasticity and mechanical properties, especially at low temperatures. Ingredients are too low, which is not preferred as above. The low molecular weight component (II) ethylene / α
The olefin copolymer has (e) an intrinsic viscosity (η ₂ ) of 0.2
To 1.6 dl / g, preferably 0.3 to 1.5 dl / g, more preferably 0.4 to 1.4 dl / g, and (f) the density (d ₂ ) is 0.890 to 0.980 g / cm ³ ,
Preferably, it is in the range of 0.890 to 0.975 g / cm ³ . When the intrinsic viscosity (η ₂ ) is less than 0.2 dl / g, the mechanical properties of the obtained composition, particularly at low temperatures, are inferior. Any of these is not preferred because the flow characteristics deteriorate. Further, those having a density (d ₂ ) of less than 0.890 g / cm ³ are not preferred because they are difficult to produce and cause stickiness of the obtained composition. On the other hand, when d ₂ exceeds 0.980 g / cm ³ , not only is production difficult, but also mechanical properties of the obtained composition are deteriorated, which is similarly unfavorable. The ethylene (co) polymer obtained by high-pressure radical polymerization of the component (III) of the present invention is a low-density polyethylene;
Ethylene-vinyl ester copolymers such as ethylene-vinyl acetate copolymer; ethylene-methacrylic acid copolymer;
Ethylene-α, β-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymer, ethylene-maleic anhydride copolymer; ethylene-methyl methacrylate copolymer;
Ethylene-α, β-unsaturated carboxylic acid ester copolymers such as ethylene-methyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer And the like. Among them, low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like are preferable. The melt flow (MFR) of the ethylene (co) polymer obtained by the high-pressure radical polymerization of the component (III) is 0.5.
The amount is from 0.5 to 100 g / 10 minutes, preferably from 0.1 to 50 g / 10 minutes. When low density polyethylene is used as component (III), its density ranges from 0.91 to 0.94 g / cm ³ , preferably from 0.91 to 0.935 g / cm ³ . The component (I
When an ethylene-vinyl acetate copolymer is used as II), the content of vinyl acetate is 1 to 40% by weight, preferably 3 to 30% by weight. In the case of an ethylene-ethyl acrylate copolymer, the content of ethyl acrylate is 1 to 40.
%, Preferably 3 to 30% by weight. In the present invention, the proportions of the components (I), (II) and (III) are 5 to 92% by weight of the component (I), 5 to 92% by weight of the component (II) and 3 to 50% by weight of the component (III). %, Provided that the total amount of the components (I), (II) and (III) is 100% by weight, and these amounts are selected according to the required performance for the composition. If the amount of the component (I) or the component (II) is less than 5% by weight, the melt elasticity and mechanical properties, especially at low temperatures, are not sufficient, while if it exceeds 92% by weight, the flow properties become poor. For,
Neither is preferred. It is important that the intrinsic viscosity of each component constituting the above composition satisfies the relationship of η ₁ > η ₂ , and if this is not satisfied, one of the objects of the present invention is to provide a mechanical device at low temperature. It is difficult to improve the characteristics. The ethylene resin composition of the present invention can be obtained by blending the components (I), (II) and (III) as described above, but the properties of the composition after blending are within a specific range. There must be. That is, the intrinsic viscosity of the ethylene-based resin composition is 0.7 to 6.0 dl / g, preferably 1 to 4 dl / g.
dl / g. When the intrinsic viscosity is less than 0.7 dl / g, the melt viscosity and the mechanical properties, especially at low temperatures, are insufficient. On the other hand, when the intrinsic viscosity is more than 6.0 dl / g, the flow properties are low, so both are preferable. Absent. The density of the ethylene-based resin composition is 0.890~0.950g / cm ^3, preferably 0.900~0.940g / cm ^3. 0.8 density
If it is less than 90 g / cm ^3, it is difficult to produce, and the composition becomes sticky. If it exceeds 0.950 g / cm ³ , the melt elasticity and mechanical properties become low. Furthermore, the N-value of the ethylene-based resin composition needs to be 1.7 to 3.5, and preferably 1.7 to 3.0. N-
When the value is less than 1.7, high-speed moldability is low, and when it is 3.5 or more, melt fracture is liable to occur. In the method for producing the polyethylene resin composition of the present invention , each component of the composition satisfies specific conditions.
There is no particular limitation as long as it is successful . For example, the components (I), (II) and (III) may be produced separately and then blended by a known method, or the components (I) and (II) may be subjected to two-stage polymerization or multi-stage polymerization. After production by a known polymerization method by polymerization, component (III)
May be blended. In the case of performing the blending in the former method and the latter method, a known method such as a method of kneading with a single-screw or twin-screw extruder or a Banbury mixer, or a solution mixing method can be used. Two steps
Manufactured by multi-stage polymerization or higher
The composition and each component are individually polymerized and then blended.
All of the compositions obtained have equivalent properties. The latter method using multi-stage polymerization is carried out using a plurality of reactors. For example, in the case of two-stage polymerization, the first-stage reactor corresponds to the component (I). Maintain the polymerization conditions of the high molecular weight ethylene / α-olefin copolymer, maintain the second stage reactor under the polymerization conditions of the low molecular weight polymer of component (II), and continuously polymerize the first stage polymer. This is a method in which component (I) and component (II) are produced as a mixture by circulating them in the second stage. In this case, each of the components (I) and (II) may be produced in any reactor, and the production order and the number of stages are not particularly limited. There is no particular limitation on the one-stage or multi-stage polymerization method,
Various methods such as a slurry method, a gas phase method, a solution method, and a high pressure ion method can be used. In these methods,
All the obtained compositions have the same properties. In addition, reaction temperature, pressure, etc. in these methods
Known operating conditions are, for example, Chemical Engineering, 47, [5]
(1983) Fujita, Ushida, p329 and convert
(1990.) Doi, p77. The polymerization catalyst is , for example, titanium and / or
Or Ziegler type mainly composed of transition metals such as vanadium
A catalyst can be used. Especially for producing component (I)
The catalyst needs to be a highly active Ziegler-type catalyst supported on a solid support, and its details will be described below. The high-activity Ziegler-type catalyst is prepared from an inorganic solid carrier such as metal magnesium, magnesium hydroxide, magnesium carbonate, magnesium oxide, various aluminas, silica, silica alumina, magnesium chloride or the like, or from magnesium and silicon, aluminum or calcium. Double salts, double oxides, hydrated carbonates, hydrated silicates, etc. containing the selected element, and these inorganic solid carriers were treated or reacted with oxygen-containing compounds, sulfur-containing compounds, hydrocarbons, and halogen-containing substances. To inorganic solid carriers such as
A transition metal compound, for example, a metal, such as titanium, vanadium, zirconium, or chromium, which carries a halide, an alkoxy halide, an oxide, or a halogenated oxide is used as a solid component. Organic compounds, preferably a combination of an organometallic compound of zinc or aluminum, or a combination thereof.
-Pretreated by contact with an olefin,
Usually, the catalyst activity is 50 g-polymer / g-catalyst · hr · kg / cm ² -olefin pressure or more, preferably 100 g-polymer / g-catalyst · hr · kg / cm ² -olefin pressure or more. The ethylene polymer composition of the present invention may contain other olefin polymers, rubber, etc., an antioxidant, an ultraviolet absorber, a light stabilizer, a lubricant, an antistatic agent, without departing from the gist of the present invention. Known additives such as an agent, an anti-fogging agent, an anti-blocking agent, a processing aid, a coloring pigment, a cross-linking agent, a foaming agent, an inorganic or organic filler, and a flame retardant can be compounded and used. The present invention will be described below in detail with reference to examples, but the present invention is not limited thereto. First, a test method used in the present invention will be described. (1) Intrinsic viscosity The intrinsic viscosity [η] was measured with a decalin solution at 135 ° C. (2) Density gradient tube method according to JIS K6760 (23
° C). (3) Continuous heating elution fractionation method (TREF) As described above, the method of L. Wild et al. Was used. Details of the measuring method are as follows. [Measurement Method] Into a 8.5-liter stainless steel column filled with Celite 545, 5 ml of an orthodichlorobenzene solution prepared by heating and dissolving a sample at 135 ° C. to a concentration of 0.05% by weight was injected. After 4 ℃ / min
Cool at 25 ° C. to a temperature of 25 ° C. and deposit the sample on the Celite surface. Next, while flowing orthodichlorobenzene through this column at a constant rate of 1 ml / min, the temperature is raised at a constant rate of 50 ° C./hr, and the samples are sequentially eluted. At this time, with respect to the sample eluted in the solvent, the absorption at a wave number of 2925 cm ⁻¹ of asymmetric stretching vibration of methylene was detected by an infrared detector,
By recording, the relationship between the elution temperature and the elution amount, that is, the composition distribution is obtained. (4) Area ratio S by continuous temperature rising elution fractionation method The area ratio S was calculated and calculated as described above and FIG. (5) Orthodichlorobenzene soluble matter W sample at 25 ° C 0.5 g was added to 20 ml of orthodichlorobenzene (O
In DCB), heat at 135 ° C. for 2 hours to completely dissolve the sample, and then cool to 25 ° C. in 2 hours. After leaving this solution at room temperature overnight at 25 ° C., the solution was filtered through a Teflon filter, and the filtrate was collected. The absorption at a wave number of 2950 cm ⁻¹ of asymmetric stretching vibration of methylene was measured with an infrared spectrophotometer. The sample concentration in the filtrate is quantified by the prepared calibration curve. (6) Using an N-value enhancement type flow tester (manufactured by Shimadzu Corporation)
Extruded from a 2 mmφ × 40 mm die at a resin temperature of 170 ° C., a lower test pressure of 20 kg / cm ² and a higher test pressure of 15
The apparent shear rate at 0 kg / cm ² is determined and calculated by the following equation (3). (Equation 3) (7) Melt flow rate (MFR) Measured according to JIS K6760. (Measurement temperature 190 ° C, load 2.16 kg) (8) High load melt flow rate (HLMFR) Measured according to JIS K6760. (Measurement temperature 1
90 ° C., load 21.6 kg) (9) Flow parameter (FP) FP is shown by a calculated value obtained from the following equation. FP = log (HLMFR / MFR) (10) Tensile yield strength (YTS) Measured according to JIS K6760. (Tensile speed: 50 mm / min, specimen thickness: 2 mm) (11) Tensile impact value (TIS) Measured according to ASTM D1822. (Test specimen thickness 1.5 mm) (12) Izod impact value (IIS) Measured at 23 ° C and -40 ° C according to JIS K7110 by the following method. By pressing from the sample, 2
When measuring at 3 ° C., a sheet having a thickness of 3 mm was prepared, and when measuring at −40 ° C., a sheet having a thickness of 4 mm was prepared. Preparation of the sample was performed at 23 ° C. and 50% humidity for 88 hours, and measured at 23 ° C. and −40 ° C. Where-
The sample measured at 40 ° C. was adjusted under the above conditions, and then kept in a low-temperature room whose temperature was previously adjusted to −40 ° C. for about 3 hours, and measured in the low-temperature room. Five test pieces were prepared, and an average value of five measurements was used as a measured value. (13) Bending stiffness was measured according to the provisions of JIS K7106. (Toyo Seiki
(14) Melt tension (MT) Measured by a melt tension tester manufactured by Toyo Seiki Co., Ltd. (Measurement temperature: 190 ° C.) (15) Critical shear rate (γc) Measured by a capillary rheometer manufactured by INTESCO Corporation. (Measurement temperature: 190 ° C.) (16) Melting point (Tm) The maximum peak temperature measured using a differential scanning calorimeter manufactured by Rigaku Corporation was used. (A test piece was prepared from a 0.2 mm-thick press sheet.) (17) Environmental stress crack resistance (ESCR) Constant strain ESCR F according to JIS K6760
A value of ₅₀ was measured. The method for testing the physical properties of the film is as follows. (1) Cloudiness (Haze;%) Cloudiness measured by a direct-reading haze computer (trade name: HGH-2DP, manufactured by Suga Test Instruments Co., Ltd.) according to JIS K7105. (2) Transparency (clarity;%) Transparency measured by a clarity meter (trade name: TM-10, manufactured by Murakami Color Research Laboratory). (3) Dart impact strength Measured by Method A according to ASTM D1709. (4) Tensile test Tensile fracture strength according to ASTM D882-64T,
It shows tensile elongation at break. Sample shape (strip type) 10 mm width x 125 mm length Tensile speed 500 mm / min Distance between chucks 50 mm Chart speed 100 mm / min <Example of production by two-stage polymerization> In the multistage polymerization process shown in FIG. A stirred type reactor having an internal volume of 30 liters was used as the reactor 1, a solid catalyst comprising titanium tetrachloride supported on a solid carrier containing anhydrous magnesium chloride as a component was supplied from a line 2, and triethyl aluminum (TEA) was supplied. It was supplied from line 3 as a co-catalyst, and the polymerization of ethylene and comonomer was carried out continuously under the polymerization conditions shown in Table 1. In the figure, reference numeral 4 denotes an ethylene supply line, reference numeral 5 denotes a comonomer supply line, reference numeral 6 denotes a hydrogen supply line, and reference numeral 7 denotes a solvent supply line. Polymers of A1 and A2 were produced by two-stage polymerization while changing the kind of α-olefin and polymerization conditions. Table 1 shows the polymerization conditions.
Table 2 shows the physical property evaluation results. Next, a production example of the polymer A1 will be specifically described. The polymerization conditions for the first-stage reactor 1 are as follows:
At 0 ° C. and a total pressure of 9.0 kg / cm ² G, the inside of the reactor 1 was kept full of liquid. The amount of polymer produced E1 calculated from the heat balance is 1.62 k
g / hr. A part of the polymerization product in the first-stage reactor was collected, and the polymer was recovered and measured for physical properties. Next, the slurry-like polymerization product from the first-stage reactor was introduced via a line 8 into a second-stage stirred reactor 9 having an internal volume of 70 liters by differential pressure. Ethylene, 1-butene and hydrogen were added as shown in Table 1, polymerization temperature 65 ° C., total pressure 8.8 kg / cm ² G,
The polymerization was continued while maintaining the liquid volume at 50 liters. The polymerization product exiting the second stage reactor 9 was then introduced into the flushing tank 10 via line 11. The amount of produced polymer E2 calculated from the heat balance was 1.98 kg / hr. The polymerization product was continuously withdrawn from the line 12 to recover the polymer, and its physical properties were evaluated. The finally recovered polymer product amount E is 3.
It was 60 kg / hr, which was consistent with the calculated value of E1 + E2. The average polymerization times of the first reactor 1 and the second reactor 9 were 25 minutes and 40 minutes, respectively. [Table 1] [Table 2] <Examples 1 to 8> 2 obtained by the above method
The step polymerization composition and the ethylene (co) polymer obtained by the following high-pressure radical polymerization were blended in the proportions shown in Tables 3 and 4, and a single-screw extruder (inner diameter 40 mm, screw L / D ratio 2
6; manufactured by Modern Corporation) under the following kneading conditions to prepare an ethylene-based resin composition. Tables 3 and 4 show the physical properties of the obtained composition. Ethylene (co) polymer by high pressure radical polymerization: (1) Low density polyethylene (1) MFR 1.0 g / 10 min, density 0.924 g / cm ³ ;
Nisseki Lexlon F22, manufactured by Nippon Petrochemical Co., Ltd.
DPE-1 ". (2) Low density polyethylene (2) MFR 2.0 g / 10 min, density 0.924 g / cm ³ ; Trade name: Nisseki Lexlon F311, manufactured by Nippon Petrochemical Co., Ltd.
DPE-2 ". (3) Ethylene-vinyl acetate copolymer MFR 1.0 g / 10 min, vinyl acetate (VA) content 10% by weight; trade name: Nisseki Lexlon V260, Nippon Petrochemical
The product is hereinafter referred to as “EVA”. (4) Ethylene-ethyl acrylate copolymer MFR 1.0 g / 10 min, ethyl acrylate (EA) content 5% by weight; trade name: Nisseki Lexlon EEA A205
0, manufactured by Nippon Petrochemical Co., Ltd., hereinafter referred to as “EEA”. (Kneading conditions) Kneading temperature: 180 ° C Resin pressure: 130 kg / cm ² G Extrusion amount: 10 to 16 kg / hr Rotation speed: 65 rpm (constant) Charge amount: 30 kg Next, a film forming apparatus for linear low-density polyethylene (inner diameter 50 mm) ; Modern Co., Ltd.) under the following molding conditions. Tables 3 and 4 show the results of evaluating the physical properties of the film. (Molding conditions) Die: 100 mmφ spiral die, lip gap 2 mm Molding temperature: 200 ° C. Resin extrusion amount: 20 kg / hr Take-off speed: 20 m / min Bubble frost line height: 280 mm Film folding diameter: 300 mm Film thickness: 30 μm [Table 3] [Table 4] <Comparative Examples 1-2> 2 obtained by the above method
Using only the step polymerization composition, a film was prepared in the same manner as in the examples, and the physical properties were evaluated. Table 5 shows the results. Comparative Example 3 A commercially available linear low-density polyethylene (MFR 0.8 g / 10 min, density 0.920 g / cm ³ ; trade name: Nisseki Linirex AF1210, Nippon Petrochemical
Table 5 shows the physical properties of the films produced using the same (hereinafter, referred to as “LLDPE”). When the bubble frost line height was 280 mm, the bubble was unstable and the moldability was poor. Therefore, the film was formed at the same height of 200 mm. <Comparative Examples 4 to 6> Commercially available LLDPE
Then, the ethylene (co) polymer obtained by the above-mentioned high-pressure radical polymerization used in Examples was blended at a composition ratio shown in Table 5, and a composition was prepared in the same manner as in Examples to prepare films. Table 5 shows their physical properties. For the same reason as in Comparative Example 3, a film was formed with a bubble frost line height of 200 mm. [Table 5] The polyethylene resin composition of the present invention has the following features in addition to the properties of the conventional polyethylene composition, such as heat resistance, ESCR, and flexibility. (1) It is excellent in mechanical properties at low temperature, particularly low temperature Izod impact value, and cold resistance. (2) Good mechanical properties such as tensile properties, bending stiffness, environmental stress crack resistance, and creep resistance. (3) Since it has excellent melt elasticity such as melt tension and flow characteristics such as critical shear rate, it has good moldability such as high-speed moldability. (4) Good optical characteristics such as haze and clarity. As a result of the above advantages, it is used for various films, sheets, pipes, hollow containers, various coating materials, foam materials, and the like. Further, since it can be suitably used for all molding methods such as extrusion molding, hollow molding and injection molding, a wide range of molded products can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an area ratio S in an elution temperature-elution amount curve by a continuous heating elution fractionation method (TREF). FIG. 2 is a schematic flow chart of a multi-stage polymerization process used in Examples of the present invention. [Description of Signs] 1 First-stage reactor 2 Catalyst supply line 3 Organometallic compound supply line 4 Ethylene supply line 5 Comonomer supply line 6 Hydrogen supply line 7 Polymerization solvent supply line 8 First-stage polymerization product transfer line 9 Second Stage reactor 10 Flushing tank 11 Second stage polymerization product transfer line 12 Polymer recovery line

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Claims (1)

(57) [Claim 1] (I) Having high activity supported on a solid carrier
5-92% by weight of a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, which satisfies the following (a) to (d) , polymerized with a Ziegler-type catalyst : (a) intrinsic viscosity (η ₁ ) 1.2 to 9.0 dl / g, (b) density (d ₁ ) 0.890 to 0.940 g / cm ³ , (c) elution temperature-elution amount curve by continuous heating elution fractionation method, elution temperature 90 The ratio S of the area Ib at an elution temperature of 25 to 90 ° C. to the area Ia under the curve of not less than
S ₁ below Ia) is calculated from the following ^{_{equation, S 1 = 20η 1 -1 exp}} [-50 (d 1 -0.900)] (d) 25 ℃ orthodichlorobenzene soluble content W wt% is calculated from the following equation that W ₁ or _{more, W 1 = 20exp (-η 1} ), (II) below (e) and ethylene homopolymer or a copolymer of ethylene and an α- olefin having 3 to 18 carbon atoms which satisfies the (f) (E) intrinsic viscosity (η ₂ ) 0.2 to 1.6 dl / g, (f) density (d ₂ ) 0.890 to 0.980 g / cm ³ , and (III) low density Ethylene (copolymer) obtained by high-pressure radical polymerization of at least one of polyethylene, ethylene-vinyl ester copolymer, ethylene-α, β-unsaturated carboxylic acid copolymer and ethylene-α, β-unsaturated carboxylic acid ester copolymer And 3) to 50% by weight of a polymer, and the total of the components (I), (II) and (III) is 100% by weight. %
And a mixture satisfying the relationship of η ₁ > η ₂ , wherein the intrinsic viscosity of the mixture is 0.7 to 6.0 dl / g and the density is 0.89.
N−0 calculated from 0 to 0.950 g / cm ³ and the following equation
An ethylene resin composition having a value of 1.7 to 3.5. (Equation 1)