JPS5966405A - Ethylenic copolymer film - Google Patents

Abstract

PURPOSE:The titled film, having a specific melt index, film density, melting point, haze, amount of an incorporated antiblocking agent and intercoat adhesive force and improved transparency, antiblocking and heat sealing properties at low temperature, and useful as packaging materials, etc. CONSTITUTION:An ethylene copolymer film prepared by molding a copolymer of ethylene with a >=4C alpha-olefin, e.g. 1-butene, into a film by using a tubular film molding machine, and having 0.5-10g/10min melt flow rate at 190 deg.C, 0.905-0.920g/cm<3> film density, plural melting points measured by a differential scanning calorimeter, >=115 deg.C maximal melting point thereof, <=10% film haze measured by the ASTM D-1003-52, <=0.15wt% amount of an incorporated antiblocking agent and <=4.0g/cm intercoat adhesive force measured by molding the films, and holding the two films at 50 deg.C under 10kg/cm<2> load for 15 days.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-density ethylene copolymer film having excellent transparency and blocking resistance.

Low-density ethylene copolymers obtained by copolymerizing ethylene and α-olefins using transition metal catalysts generally have superior tensile strength, gloss, and heat resistance compared to high-pressure polyethylene. Due to its location, it has received particular attention in recent years. In particular, when the α-olefin has 4 or more carbon atoms, especially 5 or more carbon atoms, tear strength,
It has excellent impact strength and transparency and is suitable for film applications. When these copolymers are molded into films, their transparency greatly depends on the type of copolymer and the molding method, but generally speaking, transparent films are easily blocked, especially when the density is 0. This tendency was strong when a film with excellent transparency was formed using a copolymer of .925 g/e- or less. Although there is a method of adding an anti-blocking agent such as silica to prevent blocking, this method also has its own limitations, as adding too much will reduce transparency and may have an adverse effect on the physical properties of the film. Ta. For this reason, the density of the film that achieved heat resistance A, low temperature heat sealability, impact resistance, etc. is 0.92 Q
g/cm3 or less and which has excellent transparency and anti-blocking properties has never been tested.

The present inventors have discovered that when an ethylene copolymer produced by the method described later is formed into a film by the molding method described later, a novel film with excellent transparency, blocking resistance, impact resistance, etc. The present invention was achieved based on the discovery that this can be produced.

That is, according to the present invention, (A) the melt flow rate at 190°C is 0;
．． 5 to i0g/I Qmin.

(B) Film density is 0.905 to 0.920
g/door, (C) There are multiple melting points measured by differential scanning calorimetry, and the highest melting point is 115°C or higher, (
■)) Film haze according to STM D-1003-52 is 10% or less, (E) Anti-blocking agent content 7 is O-15
t, 1wt% or less, (F) After film forming, two films were heated at 50°C1
Ethylene film whose inter-film adhesion strength is 4.3g/(?m or less) when held under a load of 10kq/an2 for 15 days.
An α-olefin copolymer film having 4 or more carbon atoms is provided.

The film of the present invention has a melt flow of 1/-) (190°
C) is 0.5 to 10 g/10 mxn, preferably 0.5 to 5 g/10 m1n, and exhibits excellent mechanical properties within this range. The density of the film of the present invention is 0.905 to 0.92 o 67cm
, preferably 0.910 to 0.920 g/cm
', and those with such density are particularly excellent in impact resistance and low-temperature heat sealability. Such 7j density films are usually formed from copolymer pellets or powders having slightly higher densities.

61 The film of the present invention has multiple melting points according to differential thermal analysis,
There are usually 2 to 3 pieces, the highest melting point of which is 115°C or higher,
In particular, the temperature is 117°C or higher. By having such a melting point, low-temperature heat-sealability is impaired and heat resistance is high. JP-A-57-105411 discloses an ethylene copolymer with a single melting point,
Such ethylene copolymers do not exhibit sufficiently satisfactory properties in terms of the balance between heat resistance and low-temperature heat sealability.

The film of the present invention meets ASTM D-1 regardless of thickness.
Items with impaired transparency that have a haze measured by the method of 003-52 of 10% or less, preferably 6% or less, and those with a haze value greater than the above range are not subject to the present invention as they have poor transparency. It is. For example, even if the same ethylene copolymer is used, the haze value will differ depending on the film forming method.
Among these, those having a haze of 10% or less are subject to the present invention. The thickness of the film is particularly between 5 and 200 mm.
A range of μ is suitable. And the film thickness is 1
When the haze value is 00μ or less, it is particularly desirable that the haze value is 6% or less.

The film of the present invention may optionally contain an anti-blocking agent, but the amount thereof should be kept to 0.15% by weight or less, particularly 0.12% by weight or less. The anti-blocking agent may be, for example, finely powdered silica, Merck, or the like.

The film of the present invention is produced by stacking two films together immediately after film forming, and applying the film under a load of 10 kq/1yn2.
A, STM-D-1 when kept at 50°C for 15 days
Adhesion strength by 893-67 is 4.3g/(71I or less,
Preferably 3.0g/equipment or less, more preferably 2.0g/equipment
g/cm or less. Note that this value was determined by opening one end of the two overlapping films after holding them above, and then using an aluminum rod to 200 mm/m1. The force applied when peeling off at a speed of n was measured using an Inteaco universal testing machine. When a film that satisfies (A) to (E) above is formed from a conventionally provided ethylene copolymer, the adhesive force can only be considerably larger than the above range, and as a result, the film cannot be used. This caused many inconveniences. For example, when using a roll of fill l, blocking may make it difficult to pull out, or when it is in the form of a bag, blocking may prevent the contents from being opened easily. The drawback was that the filling operation was complicated. However, by using the film of the present invention, these drawbacks can be overcome.

The α-olefin component of the ethylene/α-olefin copolymer film of the present invention has an ash number of 4 or more, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1 -tetradecene, 4-methyl-
1-pentene etc., especially carbon number 5 to 1o
The one having excellent mechanical strength is preferable.

The film of the present invention may contain other additives, such as antioxidants, weather stabilizers, antistatic agents, hydrochloric acid absorbers, and nucleating agents, as required.

The ethylene copolymer used as the raw material for the film of the present invention can be produced, for example, by the following method.

As a catalyst, (a) tetravalent titanium, magnesium,
・Titanium complex (1) containing rogene and an electron donor or an electron donating residue as essential components and s i, -
an organosilicon compound (11) having a 0-C bond, f
The reaction is carried out in the presence of the organoaluminium compound (liI), or after treatment with the titanium complex (D is the organoaluminum compound tube), the reaction is carried out in the presence of the organosilicon compound (11). Using a solid catalyst component formed by carrying out until at least a part of the organosilicon compound (11) is contained in the titanium composite (D) and (b) an organoaluminum compound catalyst component, Ethylene and an α-olefin having 4 or more carbon atoms are copolymerized to form a copolymer of a predetermined degree.

The details of the method for producing the solid catalyst component (a) are disclosed in Japanese Patent Application No. 1987-
No. 20857. This manufacturing method will be briefly described.

Many of the titanium composites (+) are already known as being highly active titanium catalyst components.

In general, it contains magnesium halide with low crystallinity compared to commercially available magnesium halides, and has a specific surface area of 3 m2/gs, preferably 10 to 10[]Om2/g.
1 More preferably 40 to 800 m/g,
Halogen/titanium (atomic ratio) is about 5 to about 200, especially about 5 to about 100, magnesium/titanium (1q (child ratio))
is preferably about 2 to about 100, particularly about 4 to about 50. Also, electron donors or electron-donating residues/titanium (
A molar ratio of about 0.05 to about 6, particularly about 0.1 to about 5 is preferred. Note that the titanium composite (1) may further contain other metals or elements (aluminum, tin, phosphorus, etc.). Suitable electron donors include organic or inorganic acid esters, ethers, ketones, tertiary amines, acid halides, acid anhydrides, and the like, with organic acid esters being particularly preferred. Further, a preferable -F electron-donating residue is an alkoxy group or an aryloxy group.

The above titanium composite (1) is reacted with the solid catalyst component (,
) is represented by the general formula Rn S 1(OR' )4-n (
In the formula, 0<n≦31R, R1 is a substituted or unsubstituted hydrocarbon group, -〇-n 1 dog, (4-n) 1 (which may be the same or different) It is an alkoxy(aryloxy)silicon compound that is often expressed.

A typical titanium complex (organoaluminum compound 011 used in the reaction between D and organosilicon compound (11)) has the general formula +(2Ae(oR') HX
(R2, m p q rR3 is a hydrocarbon group, X is a halogen, 0〈m〈nu m + Il
+q + r = 3), and use of trialkylaluminum is particularly preferred.

The reaction (J) is preferably carried out in an inert hydrocarbon medium, for example, the titanium complex (1) is approximately 0.0% in terms of titanium atoms.
The organosilicon compound (11) is suspended in an amount such as 0.001 to about 5 [10 mmol/e] per gram atom of titanium.
．． 05 to about 200 mol, preferably about 0.1 to about 50 mol, particularly preferably about 1 to about 40 mol,
In addition, about 0.05 to about 1000 mol, preferably about 0.05 to about 1000 mol, preferably about 0.00 mol, of organoaluminum compound 011) per 1 g atom of titanium.
1 to about 500 moles, e.g. about 90°C.
Hereinafter, contact may be carried out preferably at a temperature of about -20'C to +60'C for about 0-5 to about 1800 minutes, particularly about 1 to about 180 minutes. The amount of the organosilicon compound (11) supported is about 0.1 to about 50 mol, preferably about 0.3 to about 10 mol, more preferably about 0.6 to about 50 mol, per 1 g titanium atom.
The amount may be about 5 moles.

The organoaluminum compound catalyst component (b) used in copolymerization together with the solid catalyst component (a) obtained by the above method.
) can be exemplified by those represented by the above general formula as the organoaluminum compound 011) used in the preparation of the solid catalyst component (1).

Preferred are trialkylaluminum, alkylaluminum halides, or mixtures thereof, and particularly preferred are
, 1.5≦m≦2.5.0.5 < r < 1.5.

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 temperatures of 0 to about 300°C. Particularly in the coexistence of an inert hydrocarbon and under conditions where the ethylene copolymer dissolves, 1
When copolymerization is carried out at a temperature of about 30 to 250°C, the desired ethylene copolymer can be easily obtained.

The amount of solid catalyst component (a) used is approximately 0 in terms of titanium atoms.
．． 0005 to about 1 mmol/l, preferably about 0.00
1 to about 0.5 mmol/e, and the organoaluminum compound catalyst component (b) is A#/Ti, (atomic ratio) of about 1.
~1000, preferably about 1~500. Polymerization pressure is generally atmospheric pressure to about 1o
kq/cm', especially about 2 to about 50 kq/Cn12
It is preferable that Molecular weight modifiers such as hydrogen may be used to obtain copolymers with desired melt flow rates.

When forming a film from the copolymer thus obtained, when a copolymer pellet is used as a raw material, the density is usually slightly higher than the film density, for example, about 0.005 to 0-007 g/e-. A copolymer pellet is used. Film forming can be performed, for example, by an inflation method, a T-die method, or the like. In order to obtain a film with good transparency and a desired haze value, it is necessary to uniformly rapidly cool the film during film forming. Film forming by the inflation method is preferably carried out by the method described in Japanese Patent Application No. 11-Kaishi No. 53-146764.

Example 1 <Catalyst Preparation> Anhydrous MgCe21 was added to a flask for 31 in a nitrogen atmosphere.
90.5g (2mO1), 2-ethylhexanor/lz
325.6 g (2.5 mol), n-decane 11
was charged and heated at 120°C for 2 hours to form a homogeneous solution, and then ethyl benzoate 90-Og (0.6 mol) was added.

Next, add TLC144e to the glass flask for 10e.
was maintained at -20'C, and the homogeneous solution obtained above was added dropwise thereto over 1 hour. After keeping this under stirring at 90°C for 2 hours, the solid portion was collected by p-filtration, which was resuspended in 41 TlCe4 and heated at 90°C for 2 hours, followed by p-filtration. Washing with filtration and n-decane was repeated four times to obtain an n-decane suspension (0-19 mol of T1 was contained in the suspension).

Next, convert the above suspension into T1 and calculate 0.03ma1
/(7) and 51(oEt,)4 at room temperature under stirring.
12- was added to 41-7 g (0.20 mol) and 1 was added at room temperature.
Allowed time to react. Next, add 68-5g of Et,...,J (
0.60 mol) and further reacted for 1 hour. After the reaction, solid and liquid were separated by p-filtration, and the solid portion was further washed with n-decane, and when no Tj compound was detected in the washing solution, an n-decane suspension was prepared. In this way, a solid catalyst was obtained*2゜~1 The compositional analysis values of the solid portion are shown below.

The compositional analysis values of the solid catalyst are shown below.

3-04816 7 0-3 16 1 2.51
) Ethyl benzoate 2) 2-ethylhexoxy group 5) Ethoxy group (Polymerization) Using a continuous polymerization reactor manufactured in 2001, dehydrated and purified hexane at 1 ooe/hr, diethyl aluminum chloride 2.5 mmol/hr, and Godil. Aluminum sesquichloride was fed at 7.5 mmol/hr, the catalyst obtained above was fed at a rate of 1.0 mmol/hr in terms of Tj atoms, and at the same time, ethylene was fed at 13 kq/hr and 4-methylbenzone-1 was fed at 10 kq/hr into the polymerization vessel. , hydrogen was supplied at 8 C/hr, and the temperature was maintained at 180° C. for continuous polymerization.

The obtained copolymer pellet had an MI of 2.02 and a density of 0.
922 g/a''. Silica powder was blended as an anti-blocking agent at a ratio of Q, 1Qwt%.

Film forming A commercially available high-pressure polyethylene tubular film forming machine (manufactured by Modern Machinery) was used, and in both cases the width was 3.
It was molded into a film with a thickness of 50 mm and a thickness of 30 μm. The molding conditions were: resin temperature 180°C, screw speed 100 revolutions, gouer diameter 100mmφ, die slit width 7r++m.
It is. In order to rapidly cool the molded film, air rings were installed at two locations on the outside of the film tube. Details of the method are described in Japanese Patent Application Laid-Open No. 53-146764.

AST
Measured according to M-D-1893-67 (with one end open, 10 mm diameter aluminum rod, 200 mm/min
Intθs is the force applied to the aluminum bar when it is peeled off at a speed of
(Measured using a co universal testing machine). The temperature of 50'C was set as the most severe temperature under normal usage conditions for film blocking. Even at this temperature, the blocking power increases over time, but 15 days is sufficient time for it to reach saturation.

Heat sealability Measured according to JIS-Z-1521. Two 200 mm square films are put together and bonded using a heat sealer kept at a predetermined temperature. Next, cut into 15 mm width in the direction perpendicular to the heat-sealed line, and cut it into a 15 mm width using a tensile tester (xnt
The force at which the sheet peeled off or broke when stretched was measured using a θBQO universal testing machine. The temperature of the heat sealer was changed in 5°C increments. Generally, as the temperature rises, the seal part will easily peel off, the resin in the seal part will stretch and then break, and the resin will break somewhere other than the seal part. If the seal breaks at a location other than the sealed part, it is considered that the heat seal has been completed completely, and the temperature of the heat sealer at this time is the heat seal start temperature, and the force required to break is the heat seal strength, expressed in units of g/15 mm. Ta.

The density of the molded film is 0.916g/α3, and the haze is 3
．． 8%, and the adhesive strength was 1.4 g/z. In addition, the heat sealing start temperature is 120°C1, and the heat sealing strength is 79
It was 0g/15mm.

Examples 2 to 11 Polymerization was carried out in the same manner as in Example 1, except that the organic AI compound component, the type of α-olefin, and the MI of the copolymer were variously changed.

The amount of solid catalyst supplied is determined when the copolymer concentration in the polymerization vessel is 1.
20'g/l, and the amount of hydrogen supplied was adjusted so that the MI of the copolymer would be a predetermined value. , anhydrous MgC62
190.5 g (2 m01) and n-decane 3e were added thereto, and 552.8 g (12 mol) of ethanol was added dropwise over 1 hour while stirring, followed by reaction at room temperature for 1 hour.

To this was added 651 g of diethylaluminum chloride (5,4
mol) was added dropwise at room temperature and reacted for 1 hour. Subsequently, after adding 1138 g (6 mo1.) of titanium tetrachloride,
The temperature of the system was raised to 80°C, and the reaction was allowed to proceed with stirring for 3 hours. The generated solid part was separated by decantation, washed repeatedly with n-decane, and made into a suspension (T1 was 0 in the suspension).
．． 16mo]-included).

The compositional analysis values of the catalyst are shown below.

3.2 64 19 0-3 5.6 1) Ethoxy group (polymerization) Using the same continuous polymerization reactor as in each example, 19-gizan was added to 10Dff/hrs diethylaluminum chloride 5 mmol, /11r, ethyl Aluminum sesquichloride 5 mmol/hr, the catalyst obtained in J2 was supplied at 0.07 mmol/hr in terms of T1 atoms, and 1145 Continuous polymerization was carried out using a °CG trowel.

The MI of the obtained copolymer pellet was 2. Well, the density is 0.
It was 920 g/c1n'5. Add 0.0% of silica powder.
10 wt% was added.

The film density after molding was 0-913 g/(J', haze was 6.6%, and adhesive strength was 7.1 g/crn, which were large values.

In addition, Tm by D8C is 122.0°C and 116
．． It was 3°C.

Applicant: Mitsui Petrochemical Industries, Ltd. Agent Kazu Yamaguchi

Claims (1)

[Claims] (1) (A) Melt flow rate at 190°C is 0.5 to 10 g/10 rnin. (B) Film density is 0.905 to 0.920
B/an', (C) has multiple melting points measured by differential scanning calorimetry, and the highest melting point is 115°C or higher; (D) A
Film haze according to STM D-1003-52 is 1
0% or less, (E) The anti-blocking agent formulation t is 0.15% by weight or less, (F) After film forming, the two films are heated at 50°C.
,,The adhesion strength between the films after holding ffJll for 15 days under 10klj/CM2 load is 4. An ethylene/α-olefin copolymer film having 4 or more carbon atoms and having a molecular weight of 0.0 g/CrN or less.