JP2574605B2 - Ethylene copolymer film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an ethylene / C copolymer which has various new properties such as composition distribution characteristics, branching characteristics, randomness characteristics, and crystallinity characteristics based on the DSC melting point, which have not been described in the prior art.
Relates ₄ -C ₂₀ alpha-olefin copolymer, transparency, impact resistance, tear, blocking resistance, environmental stress cracking resistance, properties superior and excellent in these heat resistance and low-temperature heat sealability And a film of an ethylene copolymer which has not been described in a conventional document and has a good balance of

More specifically, the present invention provides the following (A)
(J) (A) The melt flow rate measured at 190 ° C. under a load of 2.16 kg is 0.01 to 200 g / 10 min. ,
(B) a density of 0.900 to 0.945 g / cm ³ ,
(C) The following formula (1)

[0003]

U = 100 × (Cw / Cn−1) (1) where Cw represents the weight average branching degree, and Cn represents the number average branching degree. U) is 40 or less, (D) the amount of the composition component having a branching degree of 2 / 1000C or less in the ethylene copolymer is 15% by weight or less, and (E) the ethylene of the composition component having a branching degree of 30 / 1000C or more. (F) n-decane-soluble component at 23 ° C. is 5% by weight or less, (G) methylene group has an average chain length ratio of 2.0 or less, H) There are n melting points (where n ≧ 2) measured by DSC (differential scanning calorimeter), and the highest melting point (T ₁ ) among the plurality of DSC melting points is

[0004]

Equation 4] (175 × d-43) ℃ ≦ T 1 ≦ 125 ℃ However Shikichu, d is a numerical value representing the density of the copolymer (g / cm ^3), the plurality and the _{T 1} The difference from the lowest melting point (Tn) among the DSC melting points is 0 ° C. <T ₁ −Tn ≦ 18 ° C., and the T ₁ and the second highest melting point among the plurality of DSC melting points ( T ₂ ) is 0 ° C. <T ₁ −T ₂ ≦ 5 ° C. However, when the DSC melting point is 2 (n = 2), 0 ° C. <T ₁ −T ₂ ≦ 5 ° C.
C. <T ₁ −T ₂ ≦ 18 ° C., (I) the highest melting point (T
₁ ) Heat of crystal dissolution (H ₁ ) and total heat of fusion of crystal (H _T )
The ratio is _{0 <H 1 / H T ≦} 0.40 in and (J) and the ethylene copolymer is ethylene _C 4 _{-C 20}
A film having excellent blocking resistance of an ethylene copolymer, characterized in that the film is a copolymer of α-olefin.

[0005] High pressure method low density polyethylene (HP-LDP)
E may be abbreviated as E) because it has the property of being flexible and having relatively good transparency, for example, a film, a hollow container, an injection molded product, a pipe, a steel pipe covering material, an electric wire covering material, and a foam molded product. Used in a wide variety of other applications. However, HP-LDPE is inferior in impact resistance, tear resistance, environmental stress cracking resistance (may be abbreviated as ESCR), etc., and is therefore excellent in these properties and has the above-mentioned good properties and these properties. It is not suitable for use in a field where a material having a good balance is used, and the use is restricted.

On the other hand, low-density polyethylene (sometimes abbreviated as L-LDPE) obtained by copolymerizing ethylene and an α-olefin of C ₃ or more under medium to low pressure conditions is HP
-It has excellent mechanical strength and ESCR as compared to LDPE, and also has good transparency, so it is attracting attention as an alternative to HP-LDPE in some application fields. However, the mechanical strength and optical properties of L-LDPE are still required to be improved, and furthermore, they do not have sufficiently satisfactory properties in terms of heat sealability. It is not possible to meet the demand for high strength by increasing the speed of the machine and reducing the thickness of the packaging material, and it is desired to develop a material that is excellent in these properties and that has the above other good properties in a well-balanced manner. Was.

[0007] The present applicant has developed a novel ethylene copolymer which meets such a demand and has disclosed in US Pat.
No. 5021 (corresponding to Japanese Patent Application Laid-Open No. 53-92987). However, the ethylene copolymer specifically disclosed in this proposal has a composition distribution characteristic that is somewhat unsatisfactory in that the composition distribution characteristic is somewhat large and contains a non-negligible amount of a low crystalline composition component. The fact that there was room for improvement in blocking resistance was changed.

On the other hand, as a proposal focusing on improvement of blocking resistance, a proposal of Japanese Patent Application Laid-Open No. 57-105411 is known. However, the DSC recommended in this proposal
Ethylene copolymer having a single melting point has a poor balance between heat resistance and low-temperature heat-sealing property, and heat resistance deteriorates when trying to improve low-temperature heat sealing property, while trying to improve heat resistance It was found that it had a drawback that the low-temperature heat sealability was inferior.

Further, JP-A-57-126809 discloses that
Ethylene / α-olefin copolymers having a specific long chain branching index and a specific short chain branch distribution have been proposed. However, this proposed copolymer has disadvantages in its composition distribution characteristics in that it has a wide composition distribution characteristic, and further, its properties such as transparency and impact resistance are unsatisfactory, and it has a good balance of various properties. It has been found that it has the disadvantage that it cannot provide a material that has been used.

[0010] As another proposal, Japanese Patent Publication No. 46-212 / 1972 is proposed.
No. 12 proposes a continuous production method for producing a uniform random partially crystalline ethylene / α-olefin copolymer having a narrow molecular weight distribution using a vanadium-based catalyst. This proposed ethylene copolymer also has a single DSC melting point, and as described above, it is difficult to combine heat resistance and low-temperature heat sealability in a well-balanced manner.

The present inventors have proposed mechanical properties, optical properties,
Research has been continued to develop an ethylene copolymer having excellent blocking resistance, heat resistance, low-temperature heat sealability, and the like, and having these excellent properties in a well-balanced manner.

As a result, in the ethylene copolymer, especially in the ethylene / C ₄ -C ₁₂ α-olefin copolymer, the combination conditions of the properties such as the composition distribution characteristics, the branching degree characteristics, the randomness characteristics, and the DSC melting point characteristics. Have been found to be important factors for the above excellent properties and their well-balanced combination.

Further, as a result of further research based on this new finding, the (J) ethylene / C ₄ -C ₂₀ α-olefin which satisfies all of the above-mentioned characteristic conditions specified in (A) to (I) above. Copolymers can be produced and have excellent transparency, impact resistance, tear resistance, blocking resistance, environmental stress crack resistance, heat resistance, low temperature heat sealability, etc., and combine these excellent properties in a well-balanced manner. It has been found that this is an ethylene copolymer not described in the conventional literature.

Accordingly, it is an object of the present invention to provide a new type of ethylene copolymer film . The above objects and many other objects and advantages of the present invention will become more apparent from the following description.

[0015] The ethylene copolymer of the present invention comprises the above (A)
To (J). Hereinafter, each characteristic will be described in detail.

The ethylene copolymer of the present invention comprises (A) 19
The melt flow rate (MFR) measured at 0 ° C. under a load of 2.16 kg is 0.01 to 200 g / 10 min. Preferably 0.05 to 150 g / 10 min. It is.

The MFR is 200 g / 10 min. If it is too large, the moldability and mechanical strength will be poor, and 0.01 g
/ 10 min. If it is too small, the moldability deteriorates, which is inconvenient.

In the present invention, (A) the MFR is AS
It is a value measured by TMD 1238E.

The ethylene copolymer of the present invention has a (B) density of 0.900 to 0.945 g / cm ³ , preferably 0.1 to 0.945 g / cm ³ .
It is 910 to 0.940 g / cm ³ .

If the density exceeds 0.945 g / cm ³ , the transparency, tear resistance, impact resistance, and low-temperature heat sealability deteriorate. If the density is less than 0.900 g / cm ³ , the resistance decreases. There is a disadvantage that the blocking property is inferior.

In the present invention, (B) the density is AST
It is a value measured by MD 1505.

The ethylene copolymer of the present invention comprises (C) a compound represented by the following formula (1):

[0023]

U = 100 × (Cw / Cn−1) (1) In the formula, Cw indicates a weight average branching degree, and Cn indicates a number average branching degree. Parameter (U) is 50 or less, for example, 0 <U ≦ 50, preferably 4.
0 or less, more preferably 30 or less.

The U is a parameter indicating the distribution of the composition components of the copolymer irrespective of the molecular weight, and is closely related to the properties (D), (E), (G) and (H) described below. It is one of the important properties for specifying the structure of the copolymer of the present invention, and if the U is too large exceeding 50, the composition distribution is too wide, and the transparency, tear resistance, impact resistance, Inferior in blocking resistance and low-temperature heat sealability,
It is difficult to exhibit the excellent properties of the copolymer of the present invention and the properties that combine the excellent properties in a well-balanced manner.

In the present invention, in the above equation (1) for calculating U, Cw and Cn are values measured and determined by the following method.

In order to fractionate the composition of the ethylene copolymer, the copolymer was added to a mixed solvent of p-xylene and butyl cellosolve (volume ratio: 80/20) with 2,5-di-tert. After dissolving in the co-presence of butyl-4-methylphenol, diatomaceous earth (trade name: Celite # 560, manufactured by John Manville Co., USA) is filled in a cylindrical column, and a solvent having the same composition as the mixed solvent is filled. The column temperature is increased stepwise from 30 ° C to 120 ° C in steps of 5 ° C while transferring and flowing out into the column. The coated ethylene copolymer is separated, then reprecipitated in methanol, filtered and dried. To obtain a separate product. Next, the number of branches C per 1000 carbon atoms of each fraction was set to 1 as in the following item (D).
Cw and Cn are determined by the least squares method, assuming that the number of branches C and the cumulative weight fraction I (w) of each classification segment follow the following logarithmic normal distribution by the 3C-NMR method.

[0027]

(Equation 6)

Where β ² is

[0029]

Β ² = 2 ln (Cw / Cn) (3) where Co ² is

[0030]

[Expression 8] Co ² = Cw · Cn (4)

The ethylene copolymer of the present invention contains (D) an ethylene copolymer having a composition degree of branching of 2 / 1000C or less (the number of branches per 1,000 main chain carbons of the copolymer is 2 or less). Is 15% by weight or less, for example, 15 to 0% by weight, preferably 10% by weight or less, more preferably 7% by weight or less.

The condition of the degree of branching of the above (D) is a parameter which means that a small amount of a component having a main chain structure with too few branches bonded to the main chain of the copolymer is small. Is closely related to the composition distribution parameter (U), and is one of the important characteristics for specifying the structure of the ethylene copolymer of the present invention together with the composition distribution parameter (U). The copolymer containing more than 15% by weight of a component having a degree of branching of 2 / 1000C or less is inferior in transparency, tear resistance, impact resistance, and low-temperature heat sealability. It is difficult to exhibit the excellent properties of the copolymer and the properties that combine the excellent properties in a well-balanced manner.

The degree of branching in the present invention is the number of branches per 1000 carbon atoms in the main chain of the copolymer, and is a value measured by the following method. That is, G. J. Ra
y, P. E. FIG. Johnson and J.M. R. Kno
x. Macromolecules, 10 , 773 (1
977), using a signal of methylene carbon observed by a carbon-13 nuclear magnetic resonance ( ¹² C-NMR) spectrum, based on the area intensity thereof.

Further, the ethylene copolymer of the present invention comprises:
(E) An amount of the composition component having a branching degree of 30 / 1000C or more in the ethylene copolymer is 15% by weight or less, for example, 1% by weight.
It is 5 to 0% by weight, preferably 13% by weight or less, more preferably 7% by weight or less.

The condition for the degree of branching of (E) is a parameter which means that a small amount of a component having a main chain structure having too many branches bonded to the main chain of the copolymer is small. Closely related to the composition distribution parameter of (A) and the degree of branching condition of (D), an important property for specifying the structure of the ethylene copolymer of the present invention together with the composition distribution parameter (U) and the degree of branching condition (C). one of. The copolymer (E) containing a component having a degree of branching of 30 / 1000C or more in excess of 15% by weight may deteriorate blocking resistance and may contaminate a contacted object. There are disadvantages.

The measurement can be determined in the same manner as in the above (D). The ethylene copolymer (F) of the present invention has an n-decane soluble content of 5 ° C at 23 ° C.
% By weight, for example, 5 to 0% by weight, preferably 3% by weight or less, more preferably 2% by weight or less.

The n-decane soluble matter (23 ° C.) is 5% by weight.
The copolymer contained excessively in excess of the above is inadequate because of poor blocking resistance, and there is a problem of contaminating the contacted object and is unsuitable, and balances the excellent properties of the copolymer of the present invention and its excellent properties. It is difficult to exhibit well-combined properties.

In the present invention, the n-decane soluble component is
10 g of ethylene copolymer in 11 of n-decane at 130 ° C
With a heat stabilizer 2,5-tert. After dissolving in the co-presence of butyl-4-methyl-phenol and keeping at 130 ° C for 1 hour, 1 ° C / min. The weight of the ethylene copolymer precipitated upon cooling to 23 ° C. at the temperature lowering rate was determined, and this value was expressed as a percentage (% by weight) of the weight obtained by subtracting from 10 g of the sample with respect to 10 g of the sample.

Further, the ethylene copolymer of the present invention comprises:
(G) The average chain length ratio of methylene groups is 2.0 or less, preferably 1.7 or less, more preferably 1.5 or less.

The average chain length ratio (G) is a parameter indicating the random structure of ethylene and α-olefin in the molecular chain of the copolymer of the present invention, and is different from the above-mentioned characteristics (C) to (E). This is one of the important characteristics that specifies the structure of the ethylene copolymer of the present invention together with the binding parameter. And
The copolymer (G) having an average chain length ratio of methylene groups exceeding 2.0, which is too large, has transparency, tear resistance, impact resistance,
It is inferior in blocking resistance and low-temperature heat sealability, and it is difficult to exhibit the excellent properties of the copolymer of the present invention and the properties combining the excellent properties in a well-balanced manner.

In the present invention, (G) the average chain length ratio of methylene groups is calculated by calculating the average chain length of methylene groups from the degree of branching calculated from the degree of branching measured using ¹³ C-NMR, This is the ratio of the block methylene average chain length calculated excluding the case where the methylene number (between two branches) is 6 or less, that is, the value obtained by the average block methylene chain length / average methylene chain length.

Further, the ethylene copolymer of the present invention comprises
(H) There are n melting points (n ≧ 2) measured by DSC (differential scanning calorimeter), and the highest melting point (T ₁ ) among the plurality of DSC melting points is

[0043]

(Equation 9) , And the difference between the T ₁ and the lowest melting point (Tn) of one of the plural DSC melting point

[0044]

10 ° C. <T ₁ −Tn ≦ 18 ° C., preferably 1 ° C. ≦ T ₁ −Tn ≦ 16 ° C., and T ₁ and the second highest melting point among the plurality of DSC melting points (T ₂ )

[0045]

0 ° C. <T ₁ −T ₂ ≦ 5 ° C., preferably 0.1 ° C. <T ₁ −T ₂ ≦ 4 ° C. However, when the DSC melting point is 2 (n = 2), 0 ° C. < T
₁₋ T ₂ ≦ 18 ° C., preferably 1 ° C. ≦ T ₁ −T ₂ ≦ 16 ° C.

The above-mentioned plurality of DSC melting points and their interrelationships are parameters relating to the crystallinity characteristics of the ethylene copolymer of the present invention due to the DSC melting point, together with the following feature (I). This is one of the important characteristics that characterizes the structure of the ethylene copolymer of the present invention, together with the binding parameter for the ethylene copolymer. In the DSC melting point characteristic of (H), if T ₁ is less than (175 × d−43) ° C. [d is as described above], the heat resistance is inferior if T ₁ is too low and T ₁ is 1
If the temperature is higher than 25 ° C., the transparency and the low-temperature heat sealability are inferior. If T ₁ -Tn is higher than 18 ° C. or T ₁ -T ₂ is higher than 5 ° C., Tear resistance,
Impact resistance, low-temperature heat sealability, and the like are deteriorated, and it is difficult to exhibit excellent properties of the copolymer of the present invention and properties that combine the excellent properties in a well-balanced manner.

In the present invention, the DSC melting point of (H), and the heat of crystal fusion (H ₁ ) and the total heat of crystal fusion (H _T ) in (I) described below are determined by the following methods. Means the value determined by

Using a differential scanning calorimeter, sample 3 mg
After melting at 00 ° C for 5 minutes, the temperature was lowered at a rate of 10 ° C / min. 2
After the temperature was lowered to 0 ° C. and maintained at this temperature for 1 minute, the temperature was raised at a rate of 10 ° C./min. By raising the temperature to 150 ° C with D
Obtain an SC endothermic curve.

Among the endothermic peaks in the DSC endothermic curve,
Intersection of highest temperature side tangent drawn at the inflection point P ₁ and the inflection point P ₂ on the low temperature side of the peak or in the accompanying FIG. 1 in T ₁ or the second graph appearing as a shoulder T ₁ (shoulder on the high temperature side of the ) Is the maximum melting point (T ₁ ). FIG. 1 and FIG.
As shown, the plurality of DSC melting point, sequentially from the hot side to the cold side, T _1, T _2, and · · · · · Tn, T ₂
Is the second highest melting point, and Tn is the lowest melting point.

On the other hand, as shown in FIGS. 1 and 2,
(In the figure, the baseline A-A ') a straight line connecting the points 60 ° C. and 130 ° C. of the DSC endothermic curve and the total heat of fusion heat quantity of the portion surrounded by the intervening endothermic curve (H _T) . If the highest melting point (T ₁ ) appears as a peak as shown in FIG. 1, a perpendicular C ₃ is lowered from the minimum point B of the curve immediately below T _{1 to} the temperature coordinate axis, and the perpendicular C ₃
Heat of crystal fusion of pace line A-A 'and (in the figure C ₂ parts) and an endothermic curve (in the figure, the curved portion C ₁ between AB) highest melting heat quantity of the applied portion hatched surrounded by (T ₁₎ (H ₁ )
In the case where the highest melting point (T ₁ ) appears as a shoulder as shown in FIG. 2, each of the inflection point P ₂ on the low temperature side of the shoulder and the inflection point P ₃ on the high temperature side of T ₂ , respectively. tangential 'down the perpendicular line C ₃ to temperatures coordinate axes, said vertical line C ₃ and the baseline a-a' intersection B of (figure C ₂ parts) and an endothermic curve (in the figure, the extension line and the curve of the C ₃ minus the The amount of heat in the hatched portion surrounded by the curved portion C ₁ ) between the intersection B ″ and A is defined as the heat of crystal fusion (H ₁ ) at the maximum melting point (T ₁ ).

The ethylene copolymer of the present invention comprises: (I) a crystal melting heat (H ₁ ) of the highest melting point (T ₁ ) of the plurality (n, where n ≧ 3) of the DSC melting points. Defined]
And the total crystal heat of fusion (H _T ) [defined above]

[0052]

0 <H ₁ / H _T ≦ 0.40, preferably 0.01 ≦ H ₁ / H _T ≦ 0.35.

The heat of crystal fusion heat ratio H ₁ / H _T of this (I) is:
DS of the ethylene copolymer of the present invention together with the property (H)
Participates in the crystalline properties due to the C melting point. If the H ₁ / H _T ratio exceeds 0.40 and is too large, the tear resistance, impact resistance, low-temperature heat sealability, and the like are deteriorated. It is useful for exhibiting the excellent properties of the coalescence and the properties that combine the excellent properties in a well-balanced manner.

Further, the ethylene copolymer of the present invention comprises
(J) Ethylene and C ₄ -C _20, preferably C ₆ -C ₁₈ α-
It is an olefin copolymer. The α-olefin may be one kind or plural kinds. Examples of such α-olefins include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-octadecene And mixtures of any two or more of these. when using propylene C ₃ as α- olefins, consequently deteriorating the tear, impact resistance and environmental stress crack resistance.

The ethylene copolymer of the present invention can be produced, for example, by the following method. For example, a titanium catalyst component (A) obtained by treating a highly active solid component (a) having titanium, magnesium and halogen as essential components and having a specific surface area of 50 m ² / g or more with an alcohol (b), an organoaluminum compound Catalyst component (B)
And a catalyst formed from the halogen compound catalyst component (C), ethylene and an α-olefin are copolymerized to a predetermined density. At this time, when part or all of the organoaluminum compound catalyst component (B) is a halogen compound, the use of the halogen compound catalyst component (C) can be omitted.

The highly active solid component (a) can itself be a highly active titanium catalyst component, and is already widely known. Basically, a magnesium compound and a titanium compound are reacted so as to obtain a solid component having a large specific surface area, with or without an auxiliary reaction reagent. The solid component (a) has a specific surface area of about 50 m ² / g.
Thus, for example, from about 50 to about 1000 m ² / g, preferably from about 80 to about 900 m ² / g, the composition of which generally has a titanium content of about 0.2 to about 18% by weight,
Preferably about 0.3 to about 15% by weight, halogen / titanium (atomic ratio) about 4 to about 300, preferably about 5 to about 300;
From about 200 to about 200, preferably from about 1.8 to about 200, preferably from about 2 to about 120, magnesium / titanium (atomic ratio).
It is. In addition to these components, other elements, metals, functional groups,
An electron donor or the like may be optionally included. For example,
Other elements and metals may include aluminum and silicon, and functional groups may include an alkoxy group and an aryloxy group. Examples of the electron donor include ethers, carboxylic acids, esters, and ketones. An example of a preferred method for producing the solid component is a method in which a complex of a magnesium halide and an alcohol is treated with an organometallic compound, and the treated product is reacted with a titanium compound. The details of this method are described in, for example, Japanese Patent Publication No. 50-27070.

The alcohol (b) used for treating the highly active solid component (a) includes aliphatic, alicyclic or aromatic alcohols, which have a substituent such as an alkoxy group. It may be something. More specifically, methanol, ethanol, n-propanol, iso-propanol, tert-butanol,
Examples thereof include n-hexanol, n-octanol, 2-ethylhexanol, n-decanol, oleyl alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, isopropylbenzyl alcohol, cumyl alcohol, and methoxyethanol. Among them, it is particularly preferable to use an aliphatic alcohol having 1 to 18 carbon atoms.

The alcohol treatment is preferably carried out in an inert hydrocarbon such as hexane, heptane or the like. For example, the solid component (a) is prepared in an amount of 0.005 to 0.2 mol / l, preferably 0.01 to 0.1 mol / l. The suspension is preferably 1 mol / l, and the alcohol is preferably brought into contact with the solid component (a) in a proportion of 1 to 80 mol, particularly 2 to 50 mol, per atom of titanium in the solid component (a). The reaction conditions vary depending on the type of alcohol, for example, about -20 ° C to about +
At a temperature of 150 ° C, preferably about -10 ° C to about + 100 ° C, for several minutes to about 10 hours, preferably about 10 hours.
The reaction is preferably performed for about a minute to about 5 hours. By the alcohol treatment, the alcohol (b) is incorporated into the solid component in the form of an alcohol and / or an alkoxy group.
The treatment is preferably carried out so that the amount is 3 to 100 mol, particularly 5 to 80 mol, per atom of titanium. Due to this reaction, a part of titanium may be eliminated from the solid component. When such a solvent-soluble component exists, after the reaction is completed, the obtained titanium catalyst component is thoroughly washed with an inert solvent. It is preferable to use for the polymerization. The organoaluminum compound catalyst component (B) used together with the titanium catalyst component (A) thus obtained typically has the general formula RnAlX _3-n (R is a hydrocarbon group such as C ₁ -C ₁₅
X is halogen, a compound represented by 0 <n ≦ 3) such as an alkyl group or a C ₂ -C ₈ alkenyl group, specifically, trialkylaluminums such as triethylaluminum and triisobutylaluminum; diethyl Examples include dialkylaluminum halides such as aluminum chloride and diisobutylaluminum chloride; alkylaluminum sesquihalides such as ethylaluminum sesquichloride and ethylaluminum sesquibromide; alkylaluminum dichlorides such as ethylaluminum dichloride; and mixtures thereof. it can. When the later-described halogen compound catalyst component (C) is not used, the average composition in the above general formula is preferably 1.5 ≦ n ≦ 2.0, more preferably 1.5 ≦ n ≦ 1.8. As described above, the component (B) is preferably used.

The halogen compound catalyst component (C) is a halogenated hydrocarbon such as ethyl chloride or isopropyl chloride, or a compound capable of acting as a halogenating agent for component (B) such as silicon tetrachloride. When a halogenated hydrocarbon is used, it can be used in an amount of about 2 to 5 mol per 1 mol of the component (B). When a halogenating agent such as silicon tetrachloride is used, the total of the halogens of the component (B) and the component (C) is 0.5 to 2 atoms, particularly, 1 atom of aluminum in the component (B). It is preferable to use them in such a ratio as to be 1 to 1.5 atoms.

The copolymerization of ethylene can be carried out in the liquid phase or in the gas phase, in the presence or absence of an inert diluent, for example at a temperature of from 0 to about 300 ° C. In particular, when copolymerization is carried out at a temperature of about 120 ° C. to 300 ° C., preferably about 130 ° C. to 250 ° C. under the condition that the ethylene copolymer is dissolved in the presence of an inert hydrocarbon, a desired ethylene copolymer is obtained. A polymer can be easily obtained. The amount of the titanium catalyst component (A) used is, for example, about 0.0005 to about 1 mmol / l, preferably about 0.001 to about 0.1 mol / l in terms of titanium atom. (B) is an amount that maintains the polymerization activity and has an Al / Ti (atomic ratio) of about 1 to about 2,
000, preferably about 10 to about 500. The polymerization pressure is generally from atmospheric pressure to about 100k
g / cm ² , preferably about 2 to about 500 kg / cm ² .

The ethylene copolymer of the present invention is HP-LDP
E, of course, is superior to conventional L-LDPE in transparency, impact resistance, tear resistance, blocking resistance, low-temperature heat sealability, heat resistance, and ESCR. Since it is provided, it is particularly suitable as a packaging film, but is not limited to this application.
It can be processed into various molded products such as films, containers, daily necessities, pipes and tubes by die molding, inflation-film molding, hollow molding, injection molding, extrusion molding, and the like. Also, various films can be formed by extrusion coating or co-extrusion molding on other films, and they are also used for applications such as steel tube covering materials, electric wire covering materials, and foam molded products. Alternatively, other thermoplastic resins such as HP-LDPE, medium density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-
It can be used by blending with a polyolefin such as methyl-1-pentene, a copolymer of low crystalline or amorphous ethylene and propylene or 1-butene, or a propylene 1-butene copolymer. Alternatively, petroleum resins, waxes, heat stabilizers, weather stabilizers, antistatic agents, anti-blocking agents, lubricants, nucleating agents, pigments, dyes, inorganic or organic fillers, synthetic rubbers or natural rubbers are used. Can also.

[0062]

【Example】

Example 1 <Catalyst preparation> Under a nitrogen atmosphere, 1 mol of commercially available anhydrous magnesium chloride was suspended in 2 L of dehydrated and purified hexane, and 6 mol of ethanol was added dropwise with stirring over 1 hour, followed by reaction at room temperature for 1 hour. . 2.6 mol of diethylaluminum chloride was added dropwise thereto at room temperature, and stirring was continued for 2 hours. Then, after adding 6 mol of titanium tetrachloride, the system was heated to 80 ° C.
And the reaction was carried out with stirring for 3 hours. The solid part after the reaction was separated and washed repeatedly with purified hexane. The composition of the solid (A-1) was as follows.

[0063]

[Table 1] Next, 500 mmol of ethanol was added at room temperature to 50 mmol of Ti in A-1 suspended in purified hexane, and the temperature was raised to 50 ° C. and reacted for 1.5 hours.
After the reaction, the solid portion was washed repeatedly with purified hexane.
The composition of the catalyst (B-1) thus obtained was as follows.

[0064]

[Table 2] *) Generated solid was quantified as ethanol in an exploded after extracting gas chromatography with H ₂ O-acetone.

<Polymerization> In a continuous polymerization reactor having an internal volume of 200 l, 100 l / hr of dehydrated and purified hexane, 7 mmol / hr of diethylaluminum chloride, 14 mmol / hr of ethylaluminum sesquichloride,
The catalyst (B-1) obtained above was converted to Ti and 0.6
Mmol / hr, and 13 kg / hr of ethylene and 4-methyl-
1-pentene: 19 kg / hr, hydrogen: continuously supplied at a rate of 45 l / hr, polymerization temperature: 165 ° C., total pressure: 30 k
The copolymerization was carried out under the conditions of g / cm ² , a residence time of 1 hour, and a copolymer temperature with respect to the solvent hexane of 130 g / l. Catalyst activity is 21,700 g-copolymer / mmol
-Ti.

Table 2 shows the results of the obtained copolymer.

Next, the copolymer was formed into a film having a width of 350 mm and a thickness of 30 μm using a commercially available tubular film molding machine for high-pressure polyethylene (manufactured by Modern Machinery). Molding conditions: resin temperature 180 ° C, screw rotation speed 100r
pm. Die slit width 0.7mm in die diameter 100mm
It is. Next, the film was evaluated by the following method.

Haze (%): ASTM D 1003 Impact strength (kg-cm / cm): Measured using a film impact tester manufactured by Toyo Seiki. The impact head sphere is 1 "
φ.

Elmendorf tear strength (kg / cm):
ASTM D1922 Blocking value (g): A peel bar made of glass and a peel speed of 20 cm / min according to ASTM D1893.
And

Heat sealing start temperature (° C.): Using a heat sealer manufactured by Toyo Tester, at a specified temperature and a pressure of 2 kg / c.
Heat sealing was performed at m ² for 1 second. The test piece width was 15 mm, and the peel test speed was 300 mm / min. The heat-sealing start temperature was a temperature at which the test piece began to break at the peeling test without depending on the peeling of the sealing surface but on the thickness-reverse portion.

Table 3 shows the results.

Examples 2 to 7 Using the same polymerization reactor and catalyst component (B-1) as in Example 1,
Continuous copolymerization was performed by changing the types of the organic Al component and the α-olefin. The polymerization conditions are shown in Table 1, and various physical properties and evaluation results of the films are shown in Tables 2 and 3.

Comparative Example 1 In Example 1, continuous copolymerization was carried out in the same manner as in Example 1 except that (A-1) before being reacted with ethanol was used instead of (B-1) as the Ti catalyst component. Was performed. The catalyst activity was 19,100 g copolymer / mmol-Ti. Table 3 shows the physical properties. The polymer obtained here has a somewhat broad composition distribution and includes those having high crystallinity and those having low crystallinity, and thus have insufficient blocking resistance.

Comparative Example 2 In the same polymerization as in Example 1, triethylaluminum 20 mmol / hr as an organic Al compound component, Ti
(A-1) before reacting with ethanol instead of (B-1) as a catalyst component was converted to Ti atom to be 0.42 mm
ol / hr, ethylene 13 kg / hr, hydrogen 40 l /
hr, 4-methyl-1-pentene was continuously supplied at a rate of 30 kg / hr to carry out polymerization. The catalytic activity is 31,
000 g-copolymer / mmol-Ti.

Table 3 shows the physical properties.

The polymer obtained here had a fairly wide composition distribution and contained many highly crystalline and low crystalline materials, and thus was inferior in transparency, blocking resistance, and low-temperature heat sealability. Comparative Example 3 The solvent dehydrated and purified in an autoclave having an internal volume of 2 l, 0.8 l of hexane and 4-methyl-1-pentene 0.1 ml.
After adding 2 l and thoroughly purging the system with nitrogen, 2.0 mmol of triethylaluminum, 0.02 mmol of Ti catalyst used in Comparative Example 2 in terms of Ti atoms were added, and then 0.6 kg / cm ^{2 of} hydrogen was added. Insert 2.5
kg / cm ² , keeping the polymerization temperature at 70 ° C.
Polymerization was carried out for hours. 295 g of the copolymer was obtained.

The catalyst activity was 14,800 g-copolymer / m
It corresponded to mol-Ti.

Table 3 shows the physical properties of the obtained copolymer.

The polymer obtained here had a very wide composition distribution and a single melting point at 124.5 ° C., and thus was inferior in low-temperature heat sealability.

[0080]

[Table 3]

[0081]

[Table 4]

[0082]

[Table 5]

[Brief description of the drawings]

FIG. 1 shows an example of an endothermic curve by DSC of the ethylene copolymer of the present invention.

FIG. 2 shows an example of an endothermic curve by DSC of the ethylene copolymer of the present invention.

Claims (1)

(57) [Claims] (A) A melt flow rate measured at 190 ° C. under a load of 2.16 kg is 0.01 to 20.
0g / 10min, (B) Density 0.900 to 0.945g / c
m ³ , (C) The following equation (1): U = 100 × (Cw / Cn−1) (1) where Cw indicates a weight average branching degree, and Cn indicates a number average branch. The composition distribution parameter (U) represented by the following formula is 40 or less; (D) the amount of the composition component having a branching degree of 2 / 1000C or less in the ethylene copolymer is 15% by weight or less; (E) the branching degree Occupies 15% by weight or less in the ethylene copolymer of a composition component of 30 / 1000C or more, (F) n-decane-soluble component at 23 ° C. is 5% by weight or less, (G) methylene group (H) n melting points (where n ≧ 2) measured by DSC (differential scanning calorimeter), and the highest melting point among the plurality of DSC melting points mp _{(T 1)} is ## EQU2 ## (175 × d-43) ≦ T 1 ≦ 125 ℃ however Wherein, d is a numerical value representing the density of the copolymer (g / cm ^3), the difference is 0 ℃ between the _{T 1} and the lowest melting point (Tn) of one of the plural DSC melting point < T ₁ is-Tn ≦ 18 ° C., and the difference is 0 ℃ between the _{T 1} and the second highest melting point of one of the plural DSC melting point _{(T 2) <T} 1 -T in ₂ ≦ 5 ° C. Yes, but 0 when the DSC melting point is 2 (n = 2)
C. <T ₁ −T ₂ ≦ 18 ° C., (I) the highest melting point (T
₁ ) Crystal heat of fusion (H ₁ ) and total crystal heat of fusion (H _T )
The ratio is _{0 <H 1 / H T ≦} 0.40 in and (J) and the ethylene copolymer is ethylene _C 4 _{-C 20}
A film excellent in blocking resistance of an ethylene copolymer, characterized in that it is a copolymer of α-olefin.