JP3399476B2 - Ethylene copolymer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ethylene copolymer, and more particularly, to excellent transparency and mechanical properties, particularly excellent impact resistance and heat sealability. The present invention relates to an ethylene copolymer comprising an ethylene unit and an olefin unit having 3 or more carbon atoms. [0002] Linear low-density polyethylene (L-LDP) which is generally a copolymer of ethylene and an α-olefin
E) has excellent physical properties such as transparency, heat sealability, and mechanical properties such as impact resistance, and is industrially used as a material for films, sheets, and other film molded products applied to the packaging field. Widely used. However, in recent years, further improvement in mechanical strength, transparency, and heat sealability has been required for L-LDPE due to the improvement in packaging speed accompanying the development of automatic packaging technology. Conventionally,
As a method for improving the heat sealing property, L-LDPE having a specified thermal property has been proposed. For example, JP-A-59-
Japanese Patent No. 75906 discloses that the ratio of the maximum melting point of crystal melting to the total crystal melting heat measured by a differential scanning calorimeter is 0.
An L-LDPE of 6 or less is disclosed. However, in the range disclosed herein, improvement in low-temperature heat sealability is still insufficient and not satisfactory. [0003] Under such circumstances, the present invention is to provide an ethylene unit having at least 3 carbon atoms having excellent transparency and mechanical properties, particularly excellent impact resistance and heat sealability. It is an object of the present invention to provide an ethylene copolymer comprising an olefin unit of formula (I). Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop an ethylene copolymer having the above preferable properties, and as a result, have found that an ethylene copolymer having a specific property is obtained. Has found that the object can be achieved.
The present invention has been completed based on such findings.
That is, the present invention provides (a) a melt index (M
I) is 0.1 to 50 g / 10 min, and (b) the density is 0.890 to
0.940 g / cm ³ , (b) (a) soluble in o-dichlorobenzene at a temperature of 35 ° C., having a content of components having a molecular weight of 1 × 10 ⁵ or more is 2.0 to 10% by weight; And (b)
Soluble in o-dichlorobenzene at a temperature of 35 ° C. and having a content of components having a molecular weight of 5 × 10 ³ or less, 1.0% by weight or less;
And (d) in a melting curve obtained by using a differential scanning calorimeter (DSC), the ratio ΔH ₉₀ / ΔH of the melting enthalpy ΔH _{90 at} the temperature of 35 to ₉₀ ° C. to the melting enthalpy ΔH at the temperature of 35 to 135 ° C. is 0.30. The present invention provides an ethylene copolymer comprising an ethylene unit and an olefin unit having 3 or more carbon atoms. [0005] The ethylene copolymer of the present invention has the following physical properties (a) to (d). (A) Melt index (MI) The MI of the ethylene copolymer needs to be in the range of 0.1 to 50 g / 10 minutes, and the MI is 0.1 g / 10
If it is less than 10 minutes, the melt viscosity becomes high and the moldability is poor.
If it exceeds 0 g / 10 minutes, not only the moldability is inferior, but also the mechanical strength is reduced. The MI is JIS K-721.
It is a value measured under the conditions of load 2160 g and temperature 190 ° C. according to 0. (B) Density The density of the ethylene copolymer is 0.890 to 0.940 g /
cm ³ , and this density is 0.8
Less than 90 g / cm ³ is inferior in rigidity and 0.940 g / cm ^3.
If it exceeds cm ³ , transparency, impact resistance and low-temperature heat sealability will decrease. The density is JIS K-711.
It is a value measured according to 2. (C) Content of a component soluble in o-dichlorobenzene at 35 ° C. The ethylene-based copolymer is (a) soluble in o-dichlorobenzene at a temperature of 35 ° C. and has a molecular weight of 1 × 10 ⁵ or more. Is in the range of 2.0 to 10% by weight, and (b) is soluble in o-dichlorobenzene at a temperature of 35 ° C., and the content of the component having a molecular weight of 5 × 10 ³ or less is 1%. 0.0% by weight
It must be: When the content of the component having a molecular weight of 1 × 10 ⁵ or more is less than 2.0% by weight, heat sealability is poor, and when it exceeds 10% by weight, rigidity is reduced. On the other hand, the content of the component having a molecular weight of 5 × 10 ³ or less is 1.0% by weight.
If it exceeds, the heat sealability will be reduced. The contents of the components having a molecular weight of 1 × 10 ⁵ or more and the contents of the components having a molecular weight of 5 × 10 ³ or less were determined by the following methods. That is, 130 ml of a polymer solution (5 g of a polymer was added to a Chromosolve packed column (50 mmφ × 300 mmH) at 135 ° C.).
And dissolved in 130 ml of o-dichlorobenzene at a temperature of 10 ° C./hr.
Then, the temperature is lowered to 30 ° C. Then 30 ° C
After recovering the components eluted by the above, the temperature is raised stepwise to 135 ° C. in increments of 5 ° C., and the components eluted at each temperature are collected. Recovery was performed by reprecipitation with 5 times the volume of acetone,
Filtration and drying (after air drying, vacuum drying at 60 ° C. for 1 day) were performed. After weighing the polymer recovered at each temperature, 3
The total weight fraction of the polymer recovered at 0 ° C. and 35 ° C. was determined, and this was defined as the 35- ° C. o-dichlorobenzene soluble part amount. The polymer recovered in this manner is G under the following conditions:
PC measurement was performed to determine the content of components having a molecular weight of 1 × 10 ⁵ or more and the content of components having a molecular weight of 5 × 10 ³ or less.
Gel permeation chromatography (GPC) measurement conditions Detector: IR detector for liquid chromatograph, wavelength 3.41μ
m Solvent: o-dichlorobenzene, measuring temperature: 135 ° C. Concentration: 0.1% (w / v), injection volume: 400 μl Column: UT806L column manufactured by Showa Denko KK, flow rate: 1.
(D) ΔH ₉₀ / ΔH The ethylene copolymer has a melting point of 35 to 135 ° C. in a melting curve obtained by using a differential scanning calorimeter (DSC).
35 to 90 for melting enthalpy ΔH in
The rate of melting enthalpy ΔH ₉₀ ° C ΔH ₉₀ / ΔH is 0.3
Must be 0 or more. This ΔH ₉₀ / ΔH is 0.
If it is less than 30, heat sealability is poor. Note that ΔH ₉₀ / Δ
H was determined as follows. That is, a sheet having a thickness of about 0.6 mm and a sample weight of about 10 mg was prepared, heat-treated at 190 ° C. for 3 minutes using a differential scanning calorimeter (DSC-7, manufactured by Perkin-Elmer), and then cooled. 1
The sample is gradually cooled to 25 ° C. at 0 ° C./min for crystallization, and the sample is heated from 25 ° C. to 160 ° C. at a rate of 10 ° C./min to obtain a melting curve. The starting point of this melting curve is 35 ° C. and the ending point is 13
A 5 ° C. baseline is drawn and this melting enthalpy ΔH
The ratio ΔH ₉₀ / ΔH of the enthalpy of fusion ΔH ₉₀ at 35 to ₉₀ ° C. to the temperature was calculated. [0008] The ethylene copolymer of the present invention having such physical properties has high transparency and mechanical properties, especially impact resistance.
Excellent heat sealability. The ethylene copolymer of the present invention is composed of an ethylene unit and an olefin unit having 3 or more carbon atoms, and the monomer forming the olefin unit includes, for example, a linear C 3 to C 18 unit. , Branched or aromatic substituted α-olefins, diolefins having 4 or more carbon atoms, polyenes, and cyclic dienes. Specific examples of the α-olefin include propylene, butene-1, hexene-1, octene-1,
Nonene-1, decene-1, undecene-1, dodecene
Linear monoolefin such as 1, 3-methylbutene-
1; 3-methylpentene-1; 4-methylpentene-
1; 2-ethyl-1,2-ethylhexene-1; 2,
Examples thereof include a branched-chain monoolefin such as 2,4-trimethylpentene-1 and a monoolefin substituted with an aromatic nucleus such as styrene. Further, as the diolefin having 4 or more carbon atoms, for example, a linear or branched non-conjugated diolefin having 6 to 20 carbon atoms, specifically 1,
5-hexadiene; 1,6-heptadiene; 1,7-octadiene; 1,8-nonadiene; 1,9-decadiene; 2,5-dimethyl-4-t-butyl-2,6-heptadiene and the like. it can. Further, examples of the polyene include 1,5,6-decatriene and the like, and examples of the cyclic diene include an endmethylene cyclic diene such as 5-vinyl-2-norbornene. In the present invention, these monomers may be used alone or in a combination of two or more. There are various methods for producing the ethylene copolymer of the present invention. For example, the following two methods can be preferably used. The first method is to prepare an ethylene copolymer satisfying the conditions (a), (b), (c)-(a) and (d) and not satisfying the conditions (c)-(b). And (c)-using an inert solvent.
This is a method that satisfies the condition (b), that is, is soluble in o-dichlorobenzene at a temperature of 35 ° C. and the content of components having a molecular weight of 5 × 10 ³ or less is 1.0% by weight or less. As the inert solvent used in this case, for example, n- or isopentane, hexane, heptane, octane, decane, tetradecane, cyclohexane, benzene, toluene, xylene and the like may be used, and these may be used alone or in combination of two or more. Although they may be used as a mixture, among them, p-xylene and n-hexane are particularly preferable. In the second method, various ethylene-based copolymers are produced using a metallocene-based catalyst and melt-kneaded, or by multistage polymerization, and further obtained by using a Ziegler-based catalyst. This is a method for producing an ethylene copolymer satisfying all of the above conditions (a), (b), (c) and (d) by blending polymers. In order to produce a film, a sheet or the like using the ethylene copolymer of the present invention, the ethylene copolymer may be used alone or an ethylene copolymer containing other additives as necessary. A polymer composition is prepared. The preparation method is not particularly limited, and the components can be satisfactorily produced by kneading each component in a molten state. As the melt-kneading apparatus, conventionally known apparatuses such as an open-type mixing roll, a non-open-type Banbury mixer, an extruder, a kneader, and a continuous mixer can be used. In preparing the copolymer composition, various additives can be blended as needed. Examples of such additives include stabilizers such as lubricants, antioxidants, and ultraviolet absorbers, and antistatic agents, flame retardants, dyes, and the like.
For example, examples of the lubricant include, but are not particularly limited to, higher aliphatic hydrocarbons, higher fatty acids, aliphatic amides, fatty acid esters, fatty acid alcohols, and polyhydric alcohols. Specifically, liquid paraffin, natural paraffin, polyethylene wax, fluorocarbon oil, lauric acid, palmitic acid, stearic acid, iristearic acid, hydroxylauric acid, hydroxystearic acid,
Oleic acid amide, lauric acid amide, erucic acid amide, methyl stearate, butyl stearate, stearyl alcohol, cetyl alcohol, isocetyl alcohol, ethylene glycol, diethylene glycol, fatty acid monoglyceride and the like can be mentioned. The thus obtained ethylene copolymer or ethylene copolymer composition of the present invention can be formed into various molded products such as films and sheets by a usual molding method. Specific examples of the molding method include a single-screw extruder, a vent-type extruder, a twin-screw extruder, a conical twin-screw extruder, a co-kneader, a plasticizer, a mixer, a twin-screw conical screw extruder. Extrusion molding, injection molding, compression molding, blow molding, rotational molding, and the like using a planetary screw extruder, a gear type extruder, a screwless extruder, and the like. Further, a film or a sheet can be formed by a T-die molding method, an inflation molding method, or the like. The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. The film quality was evaluated in the following manner. (1) Tensile modulus (MPa) Determined in accordance with JIS Z-7113. The tensile direction was the machine direction. (2) Haze (%) Determined in accordance with JIS K-7105. (3) Heat seal temperature (° C.) Determined in accordance with JIS Z-1707. Using a thermal gradient tester manufactured by Toyo Seiki Seisakusho, at a set temperature,
Heat sealing was performed at a pressure of 0.5 kg / cm ² and a sealing temperature of 1 second. The area of the seal is MD (machine direction) 10mm ×
TD (horizontal direction) 15 mm, tensile test conditions are M
The peeling test speed was 200 mm / min in the T-shaped peeling in the D direction. The temperature at which the peel strength reached 300 g / 15 mm was defined as the heat sealing temperature. Example 1 n-hexane was placed in a continuous polymerization reactor having an internal volume of 1 liter.
5.5 liter / hour, 700 g / hour of ethylene and 680 g / hour of octene-1 were supplied. As a catalyst, 1.5 mmol / h of ethyl aluminum sesquichloride, 0.5 mmol / h of ethylbutylmagnesium,
Tetrabutoxytitanium was mixed and prepared at 0.12 mmol / hour in this order and supplied to the polymerization vessel. Furthermore, sec
-Butyl chloride was fed at 0.8 mmol / hr in a separate feed line from the catalyst. 0.03 g of hydrogen
/ Hour, reaction temperature 185 ° C, reaction pressure 70kg
The polymerization reaction was carried out under the condition of / cm ² G to obtain an ethylene / octene-1 copolymer. 500 g of this copolymer was immersed in p-xylene at room temperature for 6.5 hours to reduce the components soluble in o-dichlorobenzene at 35 ° C. and having a molecular weight of 5 × 10 ³ or less. About the obtained copolymer, each physical property was measured according to the said measuring method. As the quality evaluation, a cast film was formed as described below, and each quality item was measured. First, to the obtained copolymer,
As additives, antioxidants [Irganox 1076 and Irganox 1010 (both manufactured by Ciba Geigy)], neutralizing agents [calcium stearate (manufactured by NOF Corporation)], anti-blocking agents [Silton AMT (manufactured by Mizusawa Chemical Co., Ltd.)] ] And a slip agent [Neutron S (manufactured by Nippon Seika)] in an appropriate amount to prepare a copolymer composition. The obtained copolymer composition was granulated by kneading with a single screw extruder having a diameter of 20 mmφ. Next, a cast film was formed using an extruder (manufactured by Tsukada Machine Co., Ltd.) having a diameter of 20 mmφ under the following conditions. Screw: Fulbright type L / D = 20 Clearance = 2.9, Rotation speed 1160 rpm Dice: Coat hanger type width 400 mm Lip width 0.4 mm Picking speed: 18.5 m / min Film thickness: 40 ± 2 μm Cylinder temperature from hopper 180 ~ 25 to die
The temperature was set to 0 ° C and the chill roll temperature was set to 50 ° C. Table 1 shows the physical properties of the obtained copolymer and the quality evaluation thereof. Example 2 Instead of sec-butyl chloride, t-butyl chloride was supplied at 0.4 mmol / hour, methyl-t-butyl ether was supplied at 1.0 mmol / hour, and octene-1 was supplied at 580 g / hour. Except having changed to, it carried out similarly to Example 1. Table 1 shows the physical properties of the obtained copolymer and the quality evaluation thereof. Comparative example 1 It carried out similarly to Example 1 except not having immersed the obtained copolymer in p-xylene. Table 1 shows the physical properties of the obtained copolymer and the quality evaluation thereof. Comparative Example 2 L-LDPE [Mitsui Petrochemical Co., Ltd. grade UZ1
020L] was evaluated for physical properties and quality. The results are shown in Table 1. [Table 1] According to the present invention, an ethylene copolymer comprising an ethylene unit and an olefin unit having 3 or more carbon atoms, which is excellent in transparency and mechanical properties, in particular, impact resistance and heat sealability, is produced. Obtainable. The ethylene copolymer of the present invention is suitably used for applications such as packaging films, food films, and sealant layers.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-75910 (JP, A) JP-A-2-153908 (JP, A) JP-A-63-20309 (JP, A) JP-A-3- 247606 (JP, A) JP-A-3-247607 (JP, A) JP-A-3-296510 (JP, A) JP-A-5-331237 (JP, A) JP-A-6-80727 (JP, A) JP-A-60-47010 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 10/00-10/14 C08F 110/00-110/14 C08F 210/00-210 / 18 C08F 6/00-6/28

Claims (1)

(57) [Claims] [Claim 1] (a) The melt index (MI) is 0.
1 to 50 g / 10 min, (b) Density 0.890 to 0.940
g / cm ^3, which is soluble in (c) (i) temperature 35 ° C. in o- dichlorobenzene, the content of molecular weight 1 × 10 ⁵ or more ingredients is 2.0 to 10 wt%, and ( B) Temperature 35
Soluble in o-dichlorobenzene at a temperature of 5 ° C.
The content of the component of 10 ³ or less is 1.0% by weight or less, and (d) a melting curve obtained by using a differential scanning calorimeter (DSC) shows a temperature of 35 to 90 with respect to a melting enthalpy ΔH at a temperature of 35 to 135 ° C. An ethylene copolymer comprising an ethylene unit and an olefin unit having 3 or more carbon atoms, wherein the ratio ΔH ₉₀ / ΔH of the melting enthalpy at ₉₀ ° C. ΔH ₉₀ is 0.30 or more.