JPH07165824A - Film of ethylene copolymer - Google Patents

Abstract

(57) [Summary] [Structure] Melt flow rate, density, composition distribution, 10
Ethylene and C ₄ whose degree of branching per 00 C, n-decane-soluble content, average chain length ratio of methylene groups, melting point, ratio of heat of fusion of crystals at maximum melting point and heat of fusion of all crystals satisfy predetermined conditions.
A film of a copolymer with a C ₂₀ α-olefin. [Effect] A film having excellent transparency, impact resistance, tear resistance, blocking resistance, environmental stress crack resistance, heat resistance, low temperature heat sealability, and the like, and having these excellent properties in a well-balanced manner is provided.

Description

Detailed Description of the Invention

The present invention has various characteristics such as composition distribution characteristics, branching degree characteristics, randomness characteristics, and crystallinity characteristics due to the DSC melting point.
The film of _{4 to} C ₂₀ α-olefin copolymer is excellent in transparency, impact resistance, tear resistance, blocking resistance, environmental stress crack resistance, heat resistance, low temperature heat sealability, and the like. The present invention relates to a film of an ethylene copolymer which has various properties in a well-balanced manner and which has not been described in a conventional document.

More specifically, the present invention provides the following (A) to
(J) (A) Melt flow rate measured at 190 ° C. under a load of 2.16 kg is 0.01 to 200 g / 10 m.
in. , (B) Density is from 0.900 to 0.945 g / cm
³ , (C) The following formula (1) U = 100 × (Cw / Cn−1) (1) where Cw represents the weight average branching degree and Cn represents the number average branching degree, The compositional distribution parameter (U) is 50 or less, (D) the content 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) a branching degree of 30 / 1000C. The amount of the above composition components in the ethylene copolymer is 15% by weight or less, (F) the n-decane-soluble component at 23 ° C. is 5% by weight or less, and (G) the average chain length ratio of methylene groups is 2.0 or less, (H) there are n melting points (n ≧ 2) measured by a DSC (differential scanning calorimeter), and the highest melting point (T ₁ ) of the plurality of DSC melting points. There _{T 1 = (175 × d-} 43) ℃ ~125 ℃ However Shikichu, d is the density of the copolymer ( / Cm ³⁾ is a numerical value representing the a difference between the lowest melting point (Tn) of the T ₁ and a plurality of DSC melting point thereof is _{0 ℃ <T 1 -Tn ≦ 18} ℃, and the The difference between T ₁ and the second highest melting point (T ₂ ) of the plurality of DSC melting points is 0 ° C. <T ₁ −T ₂ ≦ 5 ° C., provided that there are 2 DSC melting points (n = 2). ) For 0
° C. <according to formula of T ₁ -T ₂ ≦ 18 ℃, the highest heat of fusion of the melting point (T ₁₎ of (I) the plurality few DSC melting point (H ₁₎ and the total heat of fusion (H _T) Is 0 <H ₁ / H _T ≦ 0.40, and (J) the ethylene copolymer is a copolymer of ethylene and a C ₄ -C ₂₀ α-olefin. It relates to a film of ethylene copolymer.

High pressure method low density polyethylene (HP-LDP
(Sometimes abbreviated as E) is flexible and has relatively good transparency, and therefore, for example, film, hollow container, injection molded product, pipe, steel pipe coating material, wire coating material, foam molded product. , Used in a wide range of other applications. However, HP-LDPE has the drawback that it is inferior in impact resistance, tear resistance, environmental stress crack resistance (sometimes abbreviated as ESCR), and therefore it is excellent in these properties and also has the above-mentioned good properties and these properties. It is not suitable for use in the fields where a well-balanced material is required, and its use is restricted.

On the other hand, low density polyethylene (sometimes abbreviated as L-LDPE) obtained by copolymerizing ethylene and C ₃ or more α-olefin under medium to low pressure conditions is HP.
-Since it has properties such as excellent mechanical strength and ESCR and good transparency as compared to -LDPE, it has been attracting attention as a material replacing HP-LDPE in some fields of application. However, mechanical strength and optical properties of L-LDPE are still required to be improved, and further, heat-sealing properties do not have satisfactory properties. Therefore, in recent years, packaging of bag making machines, filling and packaging machines, etc. It is not possible to meet the requirements for high strength due to the speeding up of machines and the thinning of packaging materials, and it is desired to develop a material that is excellent in these properties and has a good balance between these other good properties and these properties. It was

The applicant of the present invention has developed a novel ethylene copolymer which meets such a demand, and has been disclosed in US Pat. No. 420.
No. 5021 (corresponding to JP-A-53-92887). However, the ethylene copolymer specifically disclosed in this proposal is not sufficiently satisfactory in its composition distribution characteristics in that the composition distribution characteristics are rather wide and the low crystalline composition component is contained in a nonnegligible amount, and as a result, It was found that there is room for improvement in blocking resistance.

On the other hand, a proposal of Japanese Patent Laid-Open No. 105-105411 is known as a proposal focusing on the improvement of blocking resistance. However, the DSC recommended for this proposal
An ethylene copolymer having a single melting point has a poor balance between heat resistance and low temperature heat sealability, and heat resistance deteriorates when trying to improve low temperature heat sealability, while on the other hand, when trying to improve heat resistance. It has been found that there is a drawback that the low temperature heat sealability becomes poor.

Further, in Japanese Patent Laid-Open No. 126809/57,
Ethylene / α-olefin copolymers having a specific long chain branching index and a specific short chain branching distribution have been proposed. However, this proposed copolymer has a wide range of composition distribution characteristics, which is problematic in its composition distribution characteristics. Furthermore, it has unsatisfactory properties such as transparency and impact resistance, and has excellent properties in a well-balanced manner. It has been found that it has the drawback of not being able to provide such materials.

As another proposal, Japanese Examined Patent Publication No. 46-212
No. 12 proposes a continuous process for producing a homogeneous 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 found that mechanical properties, optical properties,
We have been conducting research to develop an ethylene copolymer film that is excellent in blocking resistance, heat resistance, low temperature heat sealability, and the like, and that also has these excellent properties in a well-balanced manner.

As a result, in ethylene copolymers, especially in ethylene / C ₄ -C ₁₂ α-olefin copolymers, the combination conditions of the composition distribution characteristics, branching degree characteristics, randomness characteristics, DSC melting point characteristics, etc. Have been found to be an important factor in achieving the above-mentioned excellent properties and their well-balanced combination.

Further, as a result of further research based on this new finding, the above (J) ethylene / C _{4 to} C ₂₀ α-olefin which satisfies the above-mentioned characteristic conditions specified in the above (A) to (I). Copolymer film can be produced and is excellent in transparency, impact resistance, tear resistance, blocking resistance, environmental stress crack resistance, heat resistance and low temperature heat sealability, and these excellent properties are well balanced. It has been discovered that it is a film of an ethylene copolymer that has both the features and has not been 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.

The ethylene copolymer film of the present invention is
It is specified by the characteristics (A) to (J). Less than,
Each characteristic will be described in detail.

The ethylene copolymer in the present invention is
(A) Melt flow rate (MFR) measured under load of 190 ° C. and 2.16 kg is 0.01 to 200 g / 10
min. Preferably 0.05 to 150 g / 10 min.
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 less than the above range, the moldability is deteriorated, which is inconvenient.

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

The ethylene copolymer in the present invention is
(B) The density is 0.900 to 0.945 g / cm ³ , and preferably 0.910 to 0.940 g / cm ³ .

If the density exceeds 0.945 g / cm ³ and is too high, the transparency, tear resistance, impact resistance and low temperature heat sealability deteriorate, and if it is less than 0.900 g / cm ³ , the resistance is low. There is an inconvenience of poor blocking property.

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

The ethylene copolymer in the present invention is
(C) The following formula (1) U = 100 × (Cw / Cn−1) (1) where Cw represents the weight average branching degree and Cn represents the number average branching degree. The composition distribution parameter (U) is 50 or less, for example, O <U ≦ 50, preferably 4
It is 0 or less, more preferably 30 or less.

The U is a parameter showing the distribution of the composition components of the copolymer, which is irrelevant to the molecular weight, and is closely related to the characteristics (D), (E), (G), (H), etc. described later. This is one of the important properties for specifying the structure of the ethylene copolymer in the present invention. If the U exceeds 50 and is too large, the composition distribution is too wide, and the transparency, tear resistance, and
It becomes inferior in impact resistance, blocking resistance, and low-temperature heat-sealing property, and it is difficult to exhibit the excellent properties of the ethylene copolymer film of the present invention and the properties having the excellent properties in a well-balanced manner.

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

In order to carry out the composition fractionation of the ethylene copolymer, the copolymer was placed in a mixed solvent of p-xylene and butyl cellosolve (volume ratio: 80/20), and the heat stabilizer 2,5-di-tert. After being dissolved in the coexistence of butyl-4-methylphenol, diatomaceous earth (trade name: Celite # 560, manufactured by John Manville (US)) was filled in a cylindrical column, and the same composition as the above mixed solvent was filled. While the solvent in the column is being transferred into and out of the column, the column temperature is raised stepwise from 30 ° C to 5 ° C in steps of 120 ° C, the coated ethylene copolymer is separated, reprecipitated in methanol, and then filtered. -Dry to obtain a fraction. Then, the number of branches C per 1000 carbon atoms of each fraction is the same as in the following (D) term 1
Cw and Cn are obtained by the least squares method, assuming that the number of branches C and the cumulative weight fraction I (w) of each separation section follow the logarithmic normal distribution of the following formula (2) by the 3C-NMR method.

[0025]

[Equation 1]

Where β ² is represented by β ² = 2 ln (Cw / Cn) ... (3) and Co ² is represented by Co ² = Cw · Cn. .

The ethylene copolymer in the present invention is
(D) The degree of branching of 2/1000 C or less (the number of branches per 1000 main chain carbon atoms is 2 or less) in the ethylene copolymer is 15% by weight or less, for example, 15 to It is 0% by weight, preferably 10% by weight or less, more preferably 7% by weight or less.

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

The branching degree 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. Johnson and J. R. Kno
x. Macromolecules, 10 , 773 (1
977) according to the method disclosed in 977) and using the signal of methylene carbon observed by the carbon-13 nuclear magnetic resonance ( ¹³ C-NMR) spectrum, the value obtained from the area intensity.

Further, in the ethylene copolymer of the present invention, the amount of the component (E) having a branching degree of 30/1000 C or more in the ethylene copolymer is 15% by weight or less, for example, 15 to 0% by weight, preferably Is 13% by weight or less, more preferably 7% by weight or less. The branching degree condition (E) is a parameter that means that the amount of the composition component having a main chain structure with too many branches bonded to the main chain of the copolymer is small, and the composition distribution of (C) above is used. Closely related to the parameters and the branching degree condition of (D), one of the important characteristics for specifying the structure of the ethylene copolymer in the present invention together with the composition distribution parameter (U) and the branching degree condition (C). Is one. Then, (E) branching degree of 30/10
A copolymer containing more than 15% by weight of the composition component of 00C or more is inconvenient because the blocking resistance is deteriorated and the contacted object may be contaminated.

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

5% by weight of the n-decane-soluble component (23 ° C.)
A copolymer that is contained in excess of more than 1 is inadequate because of poor blocking resistance, and there is a problem of contaminating a contacted object, and various excellent properties of the ethylene copolymer film of the present invention and its excellent It is difficult to exhibit the well-balanced properties of the above properties.

In the present invention, the n-decane-soluble component is
Ethylene copolymer 10 g per liter of n-decane at 130 ° C
Is a heat-resistant stabilizer 2,5-tert.butyl-4-methyl-
It was dissolved in the presence of phenol and kept at 130 ° C for 1 hour, and then at 1 ° C / min. The weight of the ethylene copolymer precipitated upon cooling to 23 ° C. at the temperature lowering rate was calculated, and this value is a value expressed as a percentage (wt%) of the weight subtracted from 10 g of the sample to 10 g of the sample.

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

The average chain length ratio of (G) is a parameter showing the random structure of ethylene and α-olefin in the molecular chain of the ethylene copolymer of the present invention, and is the same as in the above (C) to (E). It is one of the important properties that specify the structure of the ethylene copolymer in the present invention together with the property and the binding parameter. The copolymer having an average chain length ratio of the methylene group (G) exceeding 2.0 and being too large is inferior in transparency, tear resistance, impact resistance, blocking resistance, and low temperature heat sealability. It is difficult to exhibit the excellent properties of the film of the ethylene copolymer of the present invention and the properties having the excellent properties in a well-balanced manner.

In the present invention, the average chain length ratio of the (G) methylene group is the average chain length of methylene calculated from the degree of branching measured by ¹³ C-NMR and the distance between the branches (adjacent to each other). (Between the two branches), the ratio of the block methylene average chain lengths calculated excluding the case where the number of methylenes is 6 or less, that is, the value obtained by the block methylene average chain length / methylene average chain length.

Further, the ethylene copolymer of the present invention has (H) DSC (differential scanning calorimeter) melting points of n (where n ≧ 2), and a plurality of DSC melting points are present. The highest melting point (T ₁ ) of these is T ₁ = (175 × d−43) ° C. to 125 ° C., preferably (175 × d−42.5) ° C. to 123 ° C., where d is a copolymer Is a numerical value representing the density (g / cm ³ ), and the difference between the T ₁ and the lowest melting point (Tn) among the plurality of DSC melting points is 0 ° C. <T ₁ −Tn ≦ 18 ° C., preferably the 1 ° C. ≦ T ₁ is-Tn ≦ 16 ° C., and the difference between the melting point (T ₂₎ to a second one of said T ₁ and a plurality of DSC melting point thereof 0 ℃ <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 mutual relations are parameters relating to the crystallinity characteristics by the DSC melting point of the ethylene copolymer in the present invention together with the characteristic (I) described below, and have already been described. It is one of the important properties that specify the structure of the ethylene copolymer in the present invention together with the property and the binding parameter. And, in the DSC melting point characteristic of the (H), T ₁ is (175 × d−
43) ° C [d is as above] too low, the heat resistance is inferior, and if T ₁ is more than 125 ° C and too high, transparency and low temperature heat sealability are inferior, and T ₁ -Tn is 18 ° C. Too high or T ₁ -T ₂ exceeds 5 ° C. and is too high, tear resistance, impact resistance, low temperature heat sealability, etc. are deteriorated and the ethylene copolymer film of the present invention is It is difficult to exhibit excellent properties and a property that combines these excellent properties in a well-balanced manner.

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

Using a differential scanning calorimeter, 2 mg of sample 3 mg
After melting at 00 ° C for 5 minutes, the temperature decreasing rate was 10 ° C / min. In 2
The temperature was lowered to 0 ° C., and this temperature was maintained for 1 minute, and then the temperature rising rate was 10 ° C./min. By raising the temperature to 150 ° C at
Obtain the SC endotherm curve.

In the endothermic peak 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 highest melting point (T ₁ ). 1 and 2
As shown in the figure, for a plurality of DSC melting points, T ₁ , T ₂ , ...
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,
The heat quantity of the portion surrounded by the straight line connecting the points of 60 ° C. and 130 ° C. of the DSC endothermic curve (base line AA ′ in the figure) and the endothermic curve between them is taken as the total crystal heat of fusion (H _T ). . When the highest melting point (T ₁ ) appears as a peak as shown in FIG. 1, a perpendicular line C ₃ is drawn from the minimum point B of the curve on the low temperature side of T _{1 to} the temperature coordinate axis, and the perpendicular line C ₃
And the baseline A-A '(C ₂ part in the figure) and the heat quantity of the shaded part surrounded by the endothermic curve (curve part C ₁ between AB in the figure) is the crystal melting heat quantity of the highest melting point (T ₁ ). (H ₁ )
When the highest melting point (T ₁ ) appears as a shoulder as shown in FIG. 2, the inflection point P ₂ immediately 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 heat quantity of the shaded portion surrounded by the curve portion C ₁ ) between the intersection point B ″ and A is defined as the crystal melting heat quantity (H ₁ ) of the highest melting point (T ₁ ).

The ethylene copolymer in the present invention is
(I) The heat of fusion of crystals (H ₁ ) of the highest melting point (T ₁ ) of the plural (n, where n ≧ 3) DSC melting points [as defined above] and the heat of fusion of all crystals (H _T ). [Defined above]
And the ratio is 0 <H ₁ / H _T ≦ 0.40, preferably 0.01 ≦ H ₁ / H _T ≦ 0.35.

The crystal fusion heat quantity ratio H ₁ / H _T of this (I) is
In addition to the characteristic (H), it is involved in the crystallinity characteristic of the ethylene copolymer according to the present invention due to the DSC melting point. This H ₁
If the ratio / H _T exceeds 0.40 and is too large, tear resistance, impact resistance, low temperature heat sealability, etc. are deteriorated, and the ethylene copolymer of the present invention is produced under the conditions of bonding parameters with other properties. It is useful for exhibiting the excellent properties of the film and the properties having the excellent properties in a well-balanced manner.

Further, the ethylene copolymer in the present invention is a copolymer of (J) ethylene and a C _{4 to} C _20, preferably C _{6 to} C ₁₈ α-olefin. 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-butene.
Examples include octene, 1-decene, 1-tetradecene, 1-octadecene and mixtures of any two or more of these. C ₃ as α-olefin
When propylene is used, the tear resistance, impact resistance and environmental stress crack resistance are inferior.

The ethylene copolymer of the present invention can be produced, for example, by the following method. For example, a highly active solid component (a) containing titanium, magnesium and halogen as essential components and having a specific surface area of 50 m ² / g or more.
By using a catalyst formed from a titanium catalyst component (A), an organoaluminum compound catalyst component (B), and a halogen compound catalyst component (C) obtained by treating alcohol with alcohol (b) so that a predetermined density is obtained. Ethylene and α-
Copolymerize olefins. 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 above-mentioned highly active solid component (a) can be a highly active titanium catalyst component itself and is already widely known. Basically, a magnesium compound and a titanium compound are reacted with or without an auxiliary reaction reagent so as to obtain a solid component having a large specific surface area. The solid component (a) has a specific surface area of about 50 m ² / g.
Above, for example about 50 to about 1000 m ² / g, preferably about 80 to about 900 m ² / g, the composition generally having 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 200, magnesium / titanium (atomic ratio) of about 1.8 to about 200, preferably about 2 to about 120.
Is. In addition to these components, other elements, metals, functional groups,
An electron donor or the like may be optionally contained. For example,
Other elements and metals may include aluminum and silicon, and functional groups may include alkoxy groups and aryloxy groups. Examples of electron donors include ethers, carboxylic acids, esters, ketones, and the like. As an example of a preferable method for producing the solid component, a method of treating a complex of magnesium halide and alcohol with an organometallic compound and reacting the treated product with a titanium compound can be exemplified. Details of this method are described in, for example, Japanese Patent Publication No. 50-32270.

The alcohol (b) used in the treatment of the highly active solid component (a) may be an aliphatic, alicyclic or aromatic alcohol, which has a substituent such as an alkoxy group. It may be one. 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 these, 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 or heptane. For example, the solid component (a) is 0.005 to 0.2 mol / l, and particularly 0.01 to 0.00 mol. Suspend to 1 mol / l,
The alcohol is preferably contacted at a ratio of 1 to 80 mol, particularly 2 to 50 mol, per 1 atom of titanium in the solid component (a). Although the reaction conditions vary depending on the type of alcohol, for example, about -20 ° C to about +15.
It is advisable to carry out the reaction at a temperature of 0 ° C., preferably about −10 ° C. to about + 100 ° C. for several minutes to about 10 hours, preferably about 10 minutes to about 5 hours. By the alcohol treatment, the alcohol (b) is incorporated into the solid component in the form of alcohol and / or alkoxy group, and the amount thereof is 3 to 100 mol, particularly 5 mol per titanium atom.
It is preferable to carry out the treatment so that the amount becomes to 80 mol. A part of titanium may be desorbed from the solid component by this reaction, and when such a solvent-soluble component is present, after completion of the reaction, the obtained titanium catalyst component is thoroughly washed with an inert solvent. It is better to use it for polymerization.

Organoaluminum compound catalyst component (B) used together with the titanium catalyst component (A) thus obtained
Is typically represented by the general formula RnAlX ₃ -n (R is a hydrocarbon group, for example, a C _{1 to} C ₁₅ alkyl group, a C _{2 to} C ₈ alkenyl group, etc., X is halogen, and 0 <n ≦ 3). Compounds represented, specifically, trialkylaluminums such as triethylaluminum and triisobutylaluminum; dialkylaluminum halides such as diethylaluminum chloride and diisobutylaluminum chloride; such as ethylaluminum sesquichloride and ethylaluminum sesquibromide. Examples thereof include alkylaluminum sesquihalides; alkylaluminum dichlorides such as ethylaluminum dichloride; or mixtures thereof. When the halogen compound catalyst component (C) described below is not used,
In the above general formula, the average composition is preferably 1.5
The component (B) is preferably used so that ≦ n ≦ 2.0, and more preferably 1.5 ≦ n ≦ 1.8.

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

The ethylene copolymerization 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 0 to about 300 ° C. Particularly, when the copolymerization is carried out at a temperature of about 120 ° to 300 ° C., preferably 130 ° to 250 ° C. under the condition that the ethylene copolymer is dissolved in the presence of an inert hydrocarbon, the desired ethylene copolymer is obtained. The polymer can be easily obtained. The titanium catalyst component (A) is used in an amount of, 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, and an organoaluminum compound catalyst component. (B) is an amount that maintains the polymerization activity, and the Al / Ti (atomic ratio) is about 1 to about 2.0.
00, preferably about 10 to about 500. Polymerization pressure is generally from atmospheric pressure to about 100 kg
/ Cm ² , preferably about 2 to about 500 kg / cm ² .

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

[0054]

Example 1 <Catalyst preparation> Under a nitrogen atmosphere, 1 mol of commercially available anhydrous magnesium chloride was suspended in 2 liters of dehydrated and purified hexane, 6 mol of ethanol was added dropwise over 1 hour with stirring, and then at room temperature. Reacted for 1 hour. To this, 2.6 mol of diethylaluminum chloride was added dropwise at room temperature, and stirring was continued for 2 hours. Next, after adding 6 mol of titanium tetrachloride, the system was heated to 80 ° C.
The temperature was raised to 0 and the reaction was carried out with stirring for 3 hours. The solid portion after the reaction was separated and washed repeatedly with purified hexane. The composition of the solid (A-1) was as follows.

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Ti Cl Mg Mg Al OEt *) (wt%) ━━━━━━━━━━━━━━━ ━━━━━━━━ 3.7 67.0 20.0 0.4 4.8 ━━━━━━━━━━━━━━━━━━━━━━ Next, to Ti of A-1 suspended in purified hexane. To 50 mmol converted, 500 mmol of ethanol was added at room temperature, the temperature was raised to 50 ° C., and the reaction was carried out for 1.5 hours.
After the reaction, the solid part was repeatedly washed with purified hexane.
The composition of the catalyst (B-1) thus obtained was as follows.

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Ti Cl Mg Mg Al OEt *) (wt%) ━━━━━━━━━━━━━━━ ━━━━━━━━ 1.2 53.0 16.0 0.1 22.6 ━━━━━━━━━━━━━━━━━━━━━━ *) The generated solid is decomposed with H ₂ O-acetone and extracted with gas chromatography. Was quantified as ethanol.

<Polymerization> Using a continuous polymerization reactor having an internal volume of 200 l, 100 liter / hr of dehydrated and purified hexane, 7 mmol / hr of diethylaluminum chloride, 14 mmol / hr of ethylaluminum sesquichloride, and the catalyst obtained above ( B-1) was continuously fed at a rate of 0.6 mmol / hr in terms of Ti, and 13 kg / hr of ethylene and 4-methyl-1 were simultaneously fed in the polymerization vessel.
-Pentene 19 kg / hr, hydrogen was continuously supplied at a rate of 45 l / hr, polymerization temperature 165 ° C, total pressure 30 kg / hr
The copolymerization was carried out under the conditions of cm ^{2 for} a residence time of 1 hour and a copolymer concentration of 130 g / l with respect to the solvent hexane. Catalytic activity is 21,700 g-copolymer / mmol-
Corresponding to Ti.

The results of the copolymer thus obtained are shown in Table 2.

Next, the copolymer was made into a film having a width of 350 mm and a thickness of 30 μ using a commercially available tubular film molding machine for high pressure polyethylene (manufactured by Modern Machinery). Molding conditions are resin temperature 180 ℃, screw rotation speed 100r
pm, die diameter 100 mm, die slit width 0.7 mm
Is. Next, the film was evaluated by the following methods.

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

Elmendorf tear strength (kg / cm):
ASTM D 1922 blocking value (g): According to ASTM D 1893,
The peeling bar was made of glass and the peeling speed was 20 cm / min.

Heat sealing start temperature (° C.): Using a heat sealer manufactured by Toyo Tester, pressure 2 kg / c at a specified temperature
Heat sealing was performed at m ² and a sealing time of 1 second. The width of the test piece was 15 mm, and the peel test speed was 300 mm / min. The heat-sealing start temperature was set to a temperature at which the test piece started to break when the peeling test started not by peeling the seal surface but by breaking the thick portion.

The results are shown in Table 3.

Examples 2 to 7 Using the same polymerization vessel 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, various physical properties and the evaluation results of the film are shown in Tables 2 and 3.

Comparative Example 1 Continuous copolymerization as in Example 1 except that (A-1) before reacting with ethanol was used instead of (B-1) as the Ti catalyst component in Example 1. Was done. The catalytic activity was 19,100 g copolymer / mmol-Ti. The physical properties are shown in Table 3. The polymer obtained here has a rather broad composition distribution, and includes a high crystallinity and a low crystallinity, so that the blocking resistance is insufficient.

Comparative Example 2 In the same polymerization as in Example 1, triethylaluminum 20 mmol / hr and Ti were used as the organic Al compound component.
As a catalyst component, (A-1) before reacting with ethanol in place of (B-1) is converted to Ti atom and 0.42 mm
ol / hr, ethylene 13 kg / hr, hydrogen 40 l / h
Polymerization was performed by continuously supplying r, 4-methyl-1-pentene at a rate of 30 kg / hr. Catalytic activity is 31.0
Corresponding to 00 g-copolymer / mmol-Ti.

Various physical properties are shown in Table 3.

The polymer obtained here has a fairly broad composition distribution.
In addition, since it contains a lot of high crystalline and low crystalline,
Inferior in lightness, blocking resistance and low temperature heat sealability
I was there. Comparative Example 3 Dehydrated and purified solvent hex in an autoclave with an internal volume of 2 liters
0.8 liter of sun and 0.2 liter of 4-methyl-1-pentene
Then, after thoroughly replacing the system with nitrogen, triethylaluminium
2.0 mmol, Ti catalyst used in Comparative Examples 2 and 3
Is converted to Ti atoms and 0.02 mmol is added, then
0.6 kg / cm of hydrogen²Insert and insert ethylene for 2.5k
g / cm²Pressure and keep the polymerization temperature at 70 ° C at 2:00
Polymerization was carried out. 295 g of copolymer was obtained.

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

Various physical properties of the obtained copolymer are shown in Table 3.

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

[0072]

[Table 1]

[0073]

[Table 2]

[0074]

[Table 3]

[Brief description of drawings]

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

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

Claims (1)

[Claims] 1. (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) Density is 0.900 to 0.945 g / cm ³ , (C) The following formula (1) U = 100 × (Cw / Cn−1) (1) where Cw is the weight An average branching degree is shown, Cn is a number average branching degree, and the composition distribution parameter (U) represented by is 50 or less, and (D) the amount of the composition component having a branching degree of 2 pieces / 1000C or less in the ethylene copolymer. Is 15% by weight or less, (E) the amount of the composition component having a branching degree of 30/1000 C or more in the ethylene copolymer is 15% by weight or less, and (F) the n-decane-soluble component at 23 ° C. is 5% or less. % Or less, (G) the average chain length ratio of methylene groups is 2.0 or less, (H) there are n melting points (n ≧ 2) measured by DSC (differential scanning calorimeter), and highest melting point among the plurality of DSC melting point thereof (T ₁₎ is T ₁ = (175 × d- 3) ° C. to 125 ° C. However Shikichu, d is the copolymer density (g / cm ³⁾ is a numerical value representing the a, with the T ₁ lowest melting point of one of the plural DSC melting point (Tn) Is 0 ° C. <T ₁ −Tn ≦ 18 ° C., and the difference between the T ₁ and the second highest melting point (T ₂ ) of the DSC melting points is 0 ° C. <T _1. -T ₂ ≦ 5 ° C., but 0 when the DSC melting point is 2 (n = 2)
° C. <according to formula of T ₁ -T ₂ ≦ 18 ℃, the highest heat of fusion of the melting point (T ₁₎ of (I) the plurality few DSC melting point (H ₁₎ and the total heat of fusion (H _T) Is 0 <H ₁ / H _T ≦ 0.40, and (J) the ethylene copolymer is a copolymer of ethylene and a C ₄ -C ₂₀ α-olefin. A film of ethylene copolymer.