JPH09208629A - Propylene copolymer and film comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a propylene copolymer which can provide a film possessing excellent heat sealability, rigidity, transparency, slippage and other properties by copolymerizing propylene and ethylene in the presence of a catalyst under controlled production conditions. SOLUTION: Propylene is copolymerized with ethylene in the presence of a catalyst comprising a solid catalyst component, an organometal compd. catalyst component, and an electron donating compd. catalyst component under controlled ethylene feed rate, hydrogen feed rate and other conditions to obtain a propylene copolymer. This propylene copolymer has an ethylene unit content (x) wt.%) of 3 to 10wt.% and a melt index of 4 to 12g/10min. The amt. of a material extracted with a boiling diethyl ether (Ewt.%) and (x) meet the relationship represented by formula I or II. Further, the m.p. (Tm deg.C) as measured with a differential scanning calorimeter and (x) meet the relationship represented by formula III or IV, and the isotactic triad fraction of a PPP chain portion as measured using a carbon isotope by means of NMR is not less than 98mol%.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a propylene-based copolymer and a film comprising the same. More specifically, it relates to a binary random copolymer of propylene and ethylene and a film obtained by molding the same, and this film is particularly preferably used as a sealant layer of a laminated film or a coextruded laminated film.

[0002]

2. Description of the Related Art A biaxially stretched film of crystalline polypropylene (hereinafter referred to as OPP) is widely used as a packaging film by taking advantage of its excellent rigidity, transparency and moisture resistance. However, OPP has a difficulty in heat-sealing property, and has conventionally been widely used as a laminated film obtained by laminating a resin having excellent heat-sealing property as a sealant layer on one side or both sides thereof.

The T-die cast film is widely used for bread packaging and the like, but a resin excellent in heat sealing property is often used as a sealant layer and laminated or coextruded on one side or both sides thereof to form a laminated film. Is being used. These laminated films are heat-sealed to form a bag, and after filling the contents, the bag mouth is closed by heat-sealing to obtain a final product. Therefore, the most important property required for the sealant layer of the laminated film is the low-temperature heat-sealing property, which is directly related to the bag-making process and the productivity of the bag-closing process after filling the contents. Further, it is also important to exhibit sufficient heat sealing strength, to exhibit slip properties and anti-blocking properties so that the film rewinding process can be performed without hindrance, and appearance and transparency. Further, in recent years, high-speed film formation has been carried out by a large-sized molding machine in order to increase the productivity of film processing, but even in that case, it is required that the film quality does not deteriorate.

Copolymerization of ethylene or α-olefin has been widely used as a means for improving the low temperature heat sealability. However, it is necessary to copolymerize a large amount of ethylene or α-olefin in order to obtain a sufficient low-temperature heat-sealing property improving effect, and as a result, a large amount of a sticky component is formed as a by-product in the conventional technique. However, it is not practically usable because of the drawbacks such as a significant decrease in its properties. Further, as a method for solving this problem, in the prior art, a method of dissolving and removing a sticky component in an inert solvent has been attempted. However, at this time, it is unavoidable that the low-temperature melting crystal component that contributes to the low-temperature heat-sealing property is also removed, and as a result, the effect of improving the low-temperature heat-sealing property is insufficient.

[0005]

DISCLOSURE OF THE INVENTION The present invention has excellent heat-sealing properties and also has desirable properties inherent to polypropylene films, such as rigidity, anti-blocking property, slip property, and transparency. An object of the present invention is to provide a propylene-based copolymer and a film made of the propylene-based copolymer, in which deterioration of the film quality is extremely small even when the film speed is increased.

[0006]

DISCLOSURE OF THE INVENTION As a result of investigations in view of such a situation, the present inventors have found that a specific propylene-based copolymer and a film made of the same can achieve the above object, and complete the present invention. Came to. That is,
The present invention provides the following propylene-based copolymer and a film made of the same. (1) A propylene-based copolymer which is a copolymer of propylene and ethylene and satisfies the following items. Content of ethylene unit in the copolymer (χ (wt%))
Is 3 to 10 wt%. Melt index of copolymer (MI (g / 10min))
However, it is 4 to 12 g / 10 min. Boiling diethyl ether extraction (E (wt%)) and χ
Satisfies the relation of formula (I) or (II). E ≦ 0.25 χ + 1.1 (χ = 3 to 6 wt%) ・ ・ ・ (I) E ≦ 2.6 (χ = 6 to 10 wt%) ・ ・ ・ (II) Melting point (Tm measured by differential scanning calorimeter (° C)) and χ satisfy the relation of the formula (III) or (IV). Tm ≤ 140 (χ = 3 to 5 wt%) (III) Tm ≤ 165-5 χ (χ = 5 to 10 wt%) (IV) The PPP chain part measured by ¹³ C-NMR Isotactic triad fraction (mm (mol%)) is 98.0 mol%
That is all. (2) A film using the propylene-based copolymer of (1) above.

(3) A film comprising a copolymer of propylene and ethylene, which satisfies the following items Content of ethylene units in the film (χ f (wt%))
Is 3 to 10 wt%. The heat of fusion (ΔH120 (J / g)) of 120 ° C. or less measured by a differential scanning calorimeter and χf satisfy the relationship of the formula (v) or (VI). ΔH120 ≧ 14 (χf = 3 to 5 wt%) (V) ΔH120 ≧ 5 χf −11 (χf = 5 to 10 wt%) (VI) Isolation of PPP chain part measured by ¹³ C-NMR Tactic triad fraction (mm (mol%)) is 98.0 mol%
That is all. The isotactic triad fraction of the above PPP chain part means the fraction of the site where three propylene units are continuously linked isotactically in the site where three propylene units are continuously linked.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below. The propylene-based copolymer of the present invention is a copolymer of propylene and ethylene, and satisfies the following items (1) to (4). The content of ethylene units (χ (wt%)) in the propylene-based copolymer is 3 to 10 wt%, preferably 4 to 9 wt%. If χ is less than 3 wt%, the heat seal temperature cannot be lowered sufficiently. If χ exceeds 10 wt%, the rigidity is lowered, the sticky component is increased, and the anti-blocking property is lowered. Melt index of propylene-based copolymer (MI
(g / 10min)) is 4 to 12 g / 10 min, preferably 5 to 10 g / 10
min. If the MI is less than 4 g / 10 min, transparency and film impact will decrease. If the MI exceeds 12 g / 10 min, defective molding tends to occur.

Extraction amount of boiling diethyl ether (E (wt
%)) And χ satisfy the relation of equation (I) or (II). E ≦ 0.25 χ + 1.1 (χ = 3 to 6 wt%) ・ ・ ・ (I) E ≦ 2.6 (χ = 6 to 10 wt%) ・ ・ ・ (II) Antiblocking when E is more than these ranges Is reduced. Further, the heat sealing temperature cannot be sufficiently lowered. Preferably, E ≦ 0.20χ + 1.1 (χ = 3 to 6 wt%) ... (I) ′ E ≦ 2.3 (χ = 6 to 10 wt%) ... (II) ′. Melting point (Tm (° C)) and χ measured with a differential scanning calorimeter
Satisfies the relationship of formula (III) or (IV). Tm ≤ 140 (χ = 3 to 5 wt%) (III) Tm ≤ 165-5 χ (χ = 5 to 10 wt%) (IV) Heat seal when Tm is higher than these ranges The temperature cannot be lowered sufficiently. Preferably, Tm ≤ 140 (χ = 3 to 4 wt%) ... (III) 'Tm ≤ 160-5 χ (χ = 4 to 10 wt%) ... (IV)'. ^The isotactic triad fraction (mm (mol%)) of the PPP part measured by ¹³ C-NMR is 98.0 mol% or more, preferably 98.5 mol% or more. mm is 98.0 mol
If it is less than%, the sticky component is increased and the anti-blocking property is deteriorated. Further, the crystallinity is reduced and the rigidity is reduced. Furthermore, the decrease in melting point with respect to the copolymerization amount becomes small
The heat seal temperature cannot be lowered sufficiently. The film using the propylene-based copolymer described above is excellent in heat-sealing property, rigidity, anti-blocking property, slip property, and transparency, and deterioration of film quality is extremely small even when the film formation speed is increased. It becomes a film.

A film made of a copolymer of ethylene and propylene and satisfying the following requirements (1) to (3) is excellent in heat-sealing property, rigidity, anti-blocking property, slip property, transparency and film-forming speed. It is a film in which deterioration of the film quality is extremely small even when the speed is increased, and can be suitably used for a sealant layer of a laminated film. Content of comonomer unit of film (χf (wt%))
Is 3 to 10 wt%, preferably 4 to 9 wt%. χf
If less than 3 wt%, the heat seal temperature cannot be lowered sufficiently. On the other hand, when χf exceeds 10 wt%, the rigidity and anti-blocking property are deteriorated.

The heat of fusion (ΔH120 (J / g)) of 120 ° C. or less measured by a differential scanning calorimeter and χf are expressed by the formula (V) or (V
The relationship of I) is satisfied. ΔH120 ≥ 14 (χf = 3 to 5 wt%) (V) ΔH120 ≥ 5 χf -11 (χf = 5 to 10 wt%) (VI) Heat seal when ΔH120 is less than these ranges. The temperature cannot be lowered sufficiently. Preferably, ΔH120 ≧ 14 (χf = 3 to 5 wt%) ... (V) ′ ΔH120 ≧ 8χf−26 (χf = 5 to 10 wt%) ... (VI) ′

The isotactic triad fraction (mmf (mol%)) of the PPP part measured by ¹³ C-NMR is
It is 98.0 mol% or more, preferably 98.5 mol% or more.
If the mmf is less than 98.0 mol%, the sticky component increases and the anti-blocking property deteriorates. Further, the crystallinity is reduced and the rigidity is reduced. Further, the melting point is less lowered with respect to the amount of copolymerization, and the heat sealing temperature cannot be lowered sufficiently.

The above-mentioned propylene-based copolymer can be manufactured as follows, but the invention is not limited thereto. The catalyst used in the production may be formed from a solid catalyst component containing magnesium, titanium, and halogen as essential components, an organometallic compound catalyst component such as an organoaluminum compound, and an electron donor compound catalyst component such as an organosilicon compound. The following catalyst components can be typically used. A preferred carrier for the solid catalyst component is obtained from magnesium metal, an alcohol, a halogen and / or a halogen-containing compound. In this case, as the metallic magnesium, granular, ribbon-like, powder-like magnesium or the like can be used.
Further, it is preferable that the metallic magnesium has no surface formed with a coating such as magnesium oxide.

As the alcohol, it is preferable to use a lower alcohol having 1 to 6 carbon atoms. In particular, when ethanol is used, the above-mentioned carrier which remarkably improves the expression of catalytic performance can be obtained. As the halogen, chlorine, bromine, or iodine is preferable, and particularly, iodine can be suitably used. Also,
MgCl ₂ and MgI ₂ can be suitably used as the halogen-containing compound.

The amount of alcohol is preferably 2 to 100 mol, particularly preferably 5 to 50 mol, per 1 mol of metallic magnesium. The amount of the halogen or halogen-containing compound used is based on 1 gram atom of metallic magnesium.
The halogen atom or the halogen atom in the halogen-containing compound is 0.0001 g atom or more, preferably 0.001 g atom or more;
It is at least 05 gram atoms, more preferably at least 0.001 gram atoms. The halogen and the halogen-containing compound may be used each alone or two or more of them may be used in combination.

The reaction method of metallic magnesium, alcohol, halogen and / or halogen-containing compound is, for example, generation of hydrogen gas by refluxing metallic magnesium, alcohol, halogen and / or halogen-containing compound under reflux (about 79 ° C.). Until no longer recognized (usually 20-30
H) reacting to obtain a carrier. This is preferably performed in an inert gas (eg, nitrogen gas, argon gas) atmosphere.

When the obtained carrier is used for the next synthesis of the solid catalyst component, the dried carrier may be used, or the carrier may be filtered and washed with an inert solvent such as heptane. Further, this carrier is close to granular and has a sharp particle size distribution. Further, even if each particle is taken, the variation in granularity is very small. In this case, the sphericity (S) represented by the following formula (VII) is less than 1.60, especially
It is preferable that it is less than 1.40 and the particle size distribution index (P) represented by the following formula (VIII) is less than 5.0, particularly less than 4.0. S = (E1 / E2) ² ... (VII) (where E1 is the contour length of the projected particle, and E2 is the circumference of a circle equal to the projected area of the particle.) P = D90 / D10 .. (VIII) (wherein D90 means a particle size corresponding to a weight cumulative fraction of 90%. That is, the weight sum of particle groups smaller than the particle size represented by D90 is 90% of the total weight of all particles. The same applies to D10.) At least a titanium compound is brought into contact with the above carrier for the production of the solid catalyst component.

The titanium compound is represented by the general formula (IX) TiX¹ _n(OR¹)_4-n... (IX) (where X is¹Is preferably a halogen atom, especially a chlorine atom
R¹Is a hydrocarbon group having 1 to 10 carbon atoms, particularly a linear or
Is a branched alkyl group;¹When there are multiple
May be the same or different. n is 0
It is an integer of 4. )
Can be. Specifically, Ti (OiC
_ThreeH₇)_Four, Ti (OC_FourH₉)_Four, TiCl (O-
C_TwoH_Five)_Three, TiCl (O-i-C_ThreeH₇)_Three, Ti
Cl (OC_FourH₉)_Three, TiCl_Two(OC_FourH₉)
_Two, TiCl_Two(OiC_ThreeH₇)_Two, TiCl_Fouretc
Among them, especially TiCl_FourIs preferred.
The solid catalyst component is obtained by further adding an electron donating compound to the above carrier.
It is obtained by contacting. As this electron-donating compound
Is preferably an aromatic dicarboxylic acid diester,
Di-n-butyl tartrate is preferred. In addition, the above carrier
When contacting the titanium compound and the electron donating compound,
Contact with halogen-containing silicon compounds such as silicon chloride
Good.

The above solid catalyst component can be prepared by a known method. For example, there is a method in which the above carrier, the electron-donating compound and the halogen-containing silicon compound are charged into an inert hydrocarbon such as pentane, hexane, peptane or octene as a solvent, and the titanium compound is charged with stirring. Usually, the electron-donating compound is added in an amount of 0.01 to 10 mol, preferably 0.05 to 5 mol, per mol of the carrier in terms of magnesium atom. The compound is added at 1 to 50 mol, preferably 2 to 20 mol, at 0 to 200 ° C for 5 minutes to 10 hours, preferably at 30 to 150 ° C.
The contact reaction may be carried out under the condition of 30 minutes to 5 hours. After the completion of the reaction, it is preferable to wash the generated solid catalyst component with an inert hydrocarbon (for example, n-hexane or n-heptane).

Further, among the catalyst components, an organoaluminum compound can be preferably used as the organometallic compound catalyst component. As this organoaluminum compound,
Formula _{^{(X) AlR 2 n X 2}} 3-n ··· (X) ( wherein, R ² is an alkyl group, cycloalkyl group or aryl group having 1 to 10 carbon atoms, X ² is a halogen atom And a chlorine atom or a bromine atom is preferable, and n is 1 to
It is an integer of 3. The compound represented by) is widely used. Specific examples include trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, diethylaluminum monoethoxide, and ethylaluminum sesquichloride. These may be used alone or in combination of two or more. Further, among the catalyst components, the electron donating compound component to be used in the polymerization system is preferably an organosilicon compound, and particularly preferably dicyclopentyldimethoxysilane.

The above-mentioned solid catalyst component is pretreated and then
It is good to use for polymerization. For example, an inert hydrocarbon such as pentane, hexane, peptane or octene is used as a solvent, the solid catalyst component, the organometallic compound catalyst component and the electron-donating compound component are charged, and propylene is supplied while stirring to react. Let Usually, the amount of the organometallic compound catalyst component is 0.1 to 1 mol of titanium atom in the solid catalyst component.
01 to 10 mol, preferably 0.05 to 5 mol,
The electron-donating compound component is used in an amount of 0.01 to 20 mol, preferably 0.1 to 1 mol per 1 mol of titanium atom in the solid catalyst component.
It is advisable to add up to 5 mol. Propylene is supplied under a partial pressure of propylene higher than atmospheric pressure, and at 0-100 ° C,
The pretreatment may be performed for 0.1 to 24 hours. After the completion of the reaction, it is preferable to wash the pretreated product with an inert hydrocarbon (for example, n-hexane or n-heptane). The polymerization conditions are not particularly limited, and the same conditions as known methods can be used. For example, it can be produced under a partial pressure of propylene higher than atmospheric pressure and under a temperature of -80 to 150 ° C. Preferably, at a temperature of 20 to 150 ° C., the partial pressure of propylene is in the range of atmospheric pressure to 40 kg / cm ² G. Usually, the organometallic compound catalyst component is added in an amount of 0.1 to 400 mol, preferably 1 to 200 mol, per 1 mol of titanium atom in the solid catalyst component, and the electron donating compound component is added in the solid catalyst component. 0.1 to 100 mol, preferably 1 to 50 mol, may be added to 1 mol of the titanium atom.

The ethylene partial pressure is adjusted by the ethylene supply amount so that the desired ethylene content is obtained, and the molecular weight of the copolymer is adjusted by the hydrogen supply amount so that the desired molecular weight is obtained. The propylene-based copolymer of the present invention may be blended with a commonly used antioxidant, neutralizing agent, slip agent, anti-blocking agent, antistatic agent or the like, if necessary.

Further, the propylene-based copolymer of the present invention is
A film can be formed by a melt extrusion method. For example,
In the T-die cast film forming method, the thickness is 10 to 10
It can be suitably used for forming a 500 μm film. Also,
Since it has the above-mentioned preferable characteristics, it can be suitably used as at least one layer component in the production of a laminated film by the coextrusion film forming method.

The film forming method is preferably a T-die cast film forming method in which high speed film forming is carried out by a large film forming machine, but is not particularly limited thereto, and any method can be used as long as it is a method for producing a film by a melt extrusion molding method. Even in such a film forming method, the propylene-based copolymer of the present invention can be preferably used.

[0025]

[Example 1]

(1) Preparation of magnesium compound Reaction tank with stirrer (internal volume 500 liters) Fully replaced by nitrogen gas, charged with 97.2 kg of ethanol, 640 g of iodine, and 6.4 kg of metallic magnesium, and stirred under reflux condition to bring the system into operation. The reaction was continued until the generation of hydrogen gas disappeared from the inside to obtain a solid reaction product. The reaction liquid containing the solid reaction product was dried under reduced pressure to obtain a target magnesium compound (a solid catalyst carrier). (2) Preparation of solid catalyst component Reaction tank with stirrer (internal volume 50
0 liters), 30 kg of the magnesium compound (not pulverized), 150 liters of purified heptane (n-heptane), 4.5 liters of silicon tetrachloride, and 5.4 liters of di-n-butyl phthalate were added. The inside of the system was maintained at 90 ° C, 144 liters of titanium tetrachloride was added with stirring, and the mixture was reacted at 110 ° C for 2 hours. Then, solid components were separated and washed with purified heptane at 80 ° C. Then add 228 liters of titanium tetrachloride,
After reacting at 110 ° C. for 2 hours, it was sufficiently washed with purified heptane to obtain a solid catalyst component. (3) Pretreatment Purified heptane 230 was added to a reaction vessel equipped with a stirrer with an internal volume of 500 liters.
Liters, 25 kg of the solid catalyst component and triethylaluminum based on titanium atoms in the solid catalyst component.
1.0 mol / mol, dicyclopentyldimethoxysilane 1.
Supplied at a rate of 8 mol / mol. Then, propylene was introduced until the partial pressure of propylene was 0.3 kg / cm ² G, and the temperature was 25 ° C.
For 4 hours. After the completion of the reaction, the solid catalyst component was washed several times with purified heptane, and further supplied with carbon dioxide and stirred for 24 hours. (4) Polymerization In a polymerization device with an internal volume of 200 liters equipped with a stirrer, the treated solid catalyst component is converted into titanium atom in the component at 3 mmol / hr
Triethylaluminum (4mmol / kg-PP) and dicyclopentyldimethoxysilane (1mmol / kg-PP) were supplied at a polymerization temperature of 80 ° C and a polymerization pressure (total pressure) of 28kg / cm ² G.
Then, propylene and ethylene were reacted. At this time, the ethylene concentration in the polymerization equipment was 2.9 mol% and the hydrogen concentration was 5.6 mol%.
mol% to obtain the desired ethylene content and molecular weight.

(5) Additive formulation The following additives were formulated into the propylene-based copolymer powder thus obtained, and extrusion granulated with a kneader. 1) Antioxidant Irganox 1010: 1000 ppm manufactured by Ciba Geigy and Irganox 168: 1000 ppm manufactured by Ciba Geigy 2) Neutralizer: calcium stearate: 1000 ppm 3) Antiblocking agent: 2000 ppm 4) Slup agent: erucic acid Amide: 1000 ppm

(6) Film-forming method The propylene-based copolymer pellets obtained in (5) above were processed using a 75 mmφ molding machine manufactured by Mitsubishi Heavy Industries, Ltd. to obtain a film thickness of 30 μm.
The above film was formed under the following molding conditions. Film molding (T die cast molding) processing temperature: 250 ° C, chill roll temperature: 40 ° C, take-up speed: 125 m / min. (7) Evaluation The propylene-based copolymer pellets thus obtained were evaluated for polymer properties, and for the film, polymer properties and quality were evaluated according to the methods of (8) 1) to 2). The results are shown in Table 2 or. (8) Polymer properties and film quality measurement method The film quality (items 7) to 12)) is the same after all samples were conditioned at a temperature of 23 ± 2 ° C and humidity of 50 ± 10% for 16 hours or more. The measurement was performed under temperature and humidity conditions.

1) Content of ethylene units in copolymer and film (χ, χf wt%) Ethylene content was 300 μm thick sheet prepared under the following conditions. FT / IR5300 manufactured by JASCO Corporation Using 718, 73
It was calculated from the absorbance at 3 cm ⁻¹ by the following formula.・ Sheet forming conditions: Pressing temperature: 220 ℃, Clamping pressure during heating and cold pressing: 50 kg / cm ² G, Remaining heat: 5 min, Pressurization: 5 min, Cold pressure: 3 min.・ IR measurement conditions Integration number: 20 times, resolution: 4 cm ^-1 , ethylene content (χ (wt%)) χ ₁ = 0.599 × (A ₇₃₃ / d ・ l) -0.161 × (A ₇₁₈ / d ・ l) χ ₂ = 0.599 × (A ₇₁₈ / d · l) −0.161 × (A ₇₃₃ / d · l) χ = 0.809 × (χ ₁ + χ ₂ ) where A ₇₁₈ : absorbance at 718 cm ⁻¹ , A ₇₃₃ : 733 Absorbance in cm ^-1 , d: 0.9, l: sample thickness. 2) Melt index (MI (g / 10min)) According to JIS K7210, it was measured at a temperature of 230 ° C. and a load of 2160 g. 3) Extraction amount of diethyl ether (E (wt%)) 3 g of pellets crushed to a size of 1 mmφ mesh path was put into a cylindrical filter paper, 3 g of diethyl ether as extraction solvent was put in a flat bottom flask at 160 ml, and the reflux frequency was 1 Extract for 10 hours with a Soxhlet extractor at about 5 min. After the extraction, diethyl ether was recovered by an evaporator and further dried by a vacuum drier until a constant weight was obtained to obtain a boiling diethyl ether extraction amount (E). 4) Melting point of copolymer (Tm measured by differential scanning calorimeter
(° C)) Differential scanning calorimeter (Perkin Elmer DSC7)
10 mg of sample in advance in a nitrogen atmosphere at 230 ° C
After melting for 3 min, cool down to 40 ℃ at 10 ℃ / min. After maintaining at this temperature for 3 min, the temperature was raised at 10 ° C./min, and the peak top of the maximum peak of the melting endothermic curve obtained was taken as the melting point.

5) Isotactic triad fraction (mm, mmf) of the PPP chain part of the copolymer and the film measured by ¹³ C-NMR. Isotactic triad fraction of the PPP chain part of the polypropylene copolymer. Is the isotactic fraction of triad units in the PPP chain of the copolymer molecular chain.
And can be determined from the ¹³ C-NMR spectrum. In the case of homopropylene, it can be calculated by the following formula (1).

[0030]

[Equation 1]

The same applies to mmf (mol%). However, Imm,
Imr and Irr represent peak intensities of respective regions when the methyl carbon region is divided into three regions of mm, mr and rr in the ¹³ C-NMR spectrum. The mm region has a chemical shift of 21.4 to 22.2 ppm, the mr region has a chemical shift of 20.6 to 21.4 ppm, and the rr region has a chemical shift of 19.8 to 20.6 ppm.

In the case of polypropylene type copolymer, the absorption position of methyl carbon of propylene adjacent to ethylene is affected by ethylene. Specifically, the absorption peak of propylene methyl carbon in the EPE chain appears in the rr region, and the absorption peak of propylene methyl carbon in the center of the PPE chain appears in the mr region. The absorption peak intensity of methyl carbon of propylene in this EPE chain is Tδδ (3
It can be substituted with a peak intensity of 3.3 ppm). The absorption peak intensity of methyl carbon of propylene in the PPE chain can be substituted by the peak intensity of Sαγ (38.0 ppm).

Therefore, PP of polypropylene type copolymer
The following equation (2) is used to obtain the isotactic fraction of the triad unit of the P chain.

[0034]

[Equation 2]

The same applies to mmf (mol%). ^{The 13} C-NMR spectrum is JNM-EX400 type NM manufactured by JEOL Ltd.
It measured using the R apparatus. The measurement conditions are as follows. Sample concentration: 220 mg / NMR solvent 3 ml NMR solvent: 1,2,4-Trichlorobenzene / deuterated benzene (90 / 10vol%) Measurement temperature: 130 ℃ Pulse width: 45 ° Pulse repetition time: 4 seconds Accumulation frequency: 4000 times 6) The heat of fusion of the film at 120 ° C or less measured by a differential scanning calorimeter (ΔH120 (J / g)) Differential scanning calorimeter (DSC7 manufactured by Perkin Elmer)
10 mg sample in advance in a nitrogen atmosphere at 25 ° C.
After the temperature was held at 3 ° C for 3 min and the temperature was raised at 10 ° C / min, the heat of fusion of the portion at 120 ° C or less in the maximum peak of the melting endothermic curve was calculated. 7) Heat-sealing property It was measured according to JIS K-1707. The fusion conditions are described below. The temperature of the heat seal bar is calibrated by a surface thermometer. After sealing, the film was allowed to stand at room temperature for 24 hours, and then at room temperature, the peeling rate was 200 mm / min, and the peeling strength was measured by a T-type peeling method. The heat sealing temperature was determined by calculating the temperature at which the peel strength reached 300 g / 15 mm from a seal strength-peel strength curve. Sealing time: 2 sec, Sealing area: 15 × 10 mm, Sealing pressure: 5.3 kg / cm ² Sealing temperature: Several points to be able to interpolate heat sealing temperature.

8) Tensile Elastic Modulus It was measured by a tensile test according to JIS K7127. The measurement conditions were as follows. Crosshead speed: 500 mm / min, measuring direction: machine direction (MD direction) load cell: 10 kg 9) Anti-blocking property Depending on the peeling strength after the two superposed films are adhered under the following two conditions: evaluated. Condition-1 Temperature: 60 ℃, Time: 3 hrs, Load: 36 g / cm ² Condition-2 Temperature: 50 ℃, Time: 7 Days, Load: 15 g / cm ^{2 The} peel test conditions are as follows. is there. Test speed: 20 mm / min, load cell: 2 kg

10) Slipability The film-tensioned slet is allowed to stand on the film-tipped glass plate, and then the glass plate is tilted to evaluate the tilt angle θ tan when the slet starts to slide. Using a friction angle measuring device manufactured by Toyo Seiki Seisaku-sho, the measurement was performed under the following conditions. Measuring surface: metal roll surface / metal roll surface, tilt speed: 2.7 ° / sec, thread weight: 1 kg, thread cross-section area: 65 cm ² , face-to-face pressure: 15 g / cm ² . 11) Transparency (haze) Measured according to JIS K7105. 12) Impact resistance (film impact) In the film impact tester manufactured by Toyo Seiki Seisakusho Ltd.
It was evaluated by the impact fracture strength using a 1/2 inch impact head.

[Examples 2 to 4] The same procedure as in Example 1 was carried out except that the ethylene concentration and hydrogen concentration during the polymerization were set as shown in Table 1 and the ethylene content and the molecular weight were adjusted. Table 2 shows the results. [Comparative Example 1] Dicyclopentyldimethoxysilane was not supplied at the time of polymerization, and the ethylene concentration in the polymerization apparatus was 3.4.
The same procedure as in Example 1 was carried out except that the concentration was set to mol% and the hydrogen concentration was set to 2.4 mol%. The results are shown in Table 3. [Comparative Example 2] Diethyl phthalate was used instead of di-n-butyl phthalate, and cyclohexylmethyldimethoxysilane was used instead of dicyclopentyldimethoxysilane. The ethylene concentration in the polymerization apparatus was 2.6 mol% and the hydrogen concentration was 3.3 mol%. The same procedure as in Example 1 was carried out except that the mol% was used. The results are shown in Table 3. [Comparative Example 3] Diethyl phthalate was used instead of di-n-butyl phthalate, and cyclohexylmethyldimethoxysilane was used instead of dicyclopentyldimethoxysilane. The ethylene concentration in the polymerization apparatus was 2.2 mol% and the hydrogen concentration was 3.0 mol%. The same procedure as in Example 1 was carried out except that the mol% was used. The results are shown in Table 3.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

The polypropylene film is excellent in heat-sealing property, rigidity, anti-blocking property, slip property and transparency without deteriorating the desirable characteristics inherent to the polypropylene film, and the film quality is deteriorated even if the film forming speed is increased. Extremely small. Therefore, it can be particularly suitably used as a sealant layer of a laminated or coextruded laminated film. Since it has the above-mentioned preferable properties, it can be used as a base layer or a monolayer film of a laminated film.

According to the present invention, it is not necessary to use 1-butene or other α-olefin having 4 or more carbon atoms, and a binary random copolymer of ethylene and propylene can be used to obtain a film of the above quality. Therefore, the monomer cost can be reduced. Furthermore, the amount of copolymerization is small,
A desired effect can be added to the film quality in the range where it can be easily manufactured.

Claims (3)

[Claims] 1. A propylene-ethylene copolymer which is a copolymer of propylene and ethylene and satisfies the following items. Content of ethylene unit in the copolymer (χ (wt%))
Is 3 to 10 wt%. Melt index of copolymer (MI (g / 10min))
However, it is 4 to 12 g / 10 min. Boiling diethyl ether extraction (E (wt%)) and χ
Satisfies the relation of formula (I) or (II). E ≦ 0.25 χ + 1.1 (χ = 3 to 6 wt%) ・ ・ ・ (I) E ≦ 2.6 (χ = 6 to 10 wt%) ・ ・ ・ (II) Melting point (Tm measured by differential scanning calorimeter (° C)) and χ satisfy the relation of the formula (III) or (IV). Tm ≤ 140 (χ = 3 to 5 wt%) (III) Tm ≤ 165-5χ (χ = 5 to 10 wt%) (IV) Isolation of PPP chain part measured by ¹³ C-NMR Tactic triad fraction (mm (mol%)) is 98.0 mol%
That is all. 2. A film comprising the propylene-based copolymer according to claim 1. 3. A film comprising a copolymer of propylene and ethylene, the film satisfying the following items. Content of ethylene units in the film (χ f (wt%))
Is 3 to 10 wt%. The heat of fusion (ΔH120 (J / g)) of 120 ° C. or less measured by a differential scanning calorimeter and χf satisfy the relationship of the formula (v) or (VI). ΔH120 ≧ 14 (χf = 3 to 5 wt%) (V) ΔH120 ≧ 5 χf −11 (χf = 5 to 10 wt%) (VI) Isolation of PPP chain part measured by ¹³ C-NMR Tactic triad fraction (mm (mol%)) is 98.0 mol%
That is all.