JPS6036372B2 - Method for manufacturing polyethylene film - Google Patents

Description

[Detailed description of the invention] This invention relates to a method for manufacturing polyethylene film.

In particular, the present invention relates to a method for producing a polyethylene film that is excellent in transparency, gloss, and cloud-proofing properties, and has good closing properties when made into a bag, and is suitable as a packaging material.
Traditionally, polyethylene-based wrap films have been mainly used for food packaging, and have the advantage of being relatively inexpensive and do not emit harmful gases during molding or incineration. It has been widely used with resin wrap films. Such wrap films are used to cover and package contents by themselves, or to place packaged items such as food on a tray and then wrap the tray together with the wrap film. Various properties are required, such as transparency and gloss, as well as appropriate adhesion and antifogging properties. Recently, there has been a desire to conserve resources, and the packaging format for fresh foods using plastic wrap with a tray at stores is to cut the normally used tube-shaped film into appropriate dimensions and heat-seal one end to form a bag. There is a gradual shift to packaging formats in which the items to be packaged are stuffed. In order to obtain the chew-like film used for bags, polyethylene resin is usually used and an air-cooled blown film forming method is being explored. insufficient transparency. In order to obtain sufficient transparency, the temperature of the molten resin during film molding is raised,
In addition, so-called water-cooled blown film molding or T-die film molding, in which the molten resin is rapidly cooled to make the polyethylene spherulite size fine, can be considered, but these methods significantly improve transparency, but When used to make bags, the smoothness of the film surface tends to cause the so-called blocking phenomenon in which the films adhere to each other.

As a result, the bag has poor closing performance, making it difficult to easily open the bag with a fingertip, significantly reducing the efficiency of bag filling work, and increasing the cost of bag filling work. In order to improve flocking properties, it is possible to add inorganic fillers such as silica powder or unsaturated fatty acid amides, but if these are added in sufficient amounts to exhibit sufficient anti-blocking properties, transparency will decrease. In addition, amide appears on the surface of the film, making the film cloudy and impractical.

In view of this background, the present inventors produce a polyethylene film that maintains good transparency, has anti-blocking properties, and therefore has excellent openability when made into bags, and is extremely suitable for bag manufacturing. We researched the methods and proposed one method first. That is, for 100 parts by weight of polyethylene, the average particle size is 1 to 10 degrees, and the particle size is 0.1 to 15.
0.01 to 1 part by weight of an inorganic filler, 0.05 to 5 parts by weight of an unsaturated fatty acid amide with a melting point of 90% or less, and a carbon number of 2
Polyhydric alcohol ester of 2-26 fatty acids 0.01~
This is a method for producing a polyethylene film, characterized by extruding a polyethylene resin composition containing 6 parts by weight in a molten state from a molding machine, and rapidly cooling and solidifying it to 50 oo or less. According to this method, a polyethylene film with excellent transparency and adhesiveness can be easily produced.

However, in the wrap film obtained from this film, when vegetables, fruits, etc. are packaged with the wrap film, moisture that evaporates from the packaged object is likely to condense on the film surface and form water droplets. This has the disadvantage that it becomes difficult to see the contents.
Anti-fog agents are used to prevent this, but using regular anti-cloud agents causes a high bleed rate, and since it is in liquid form and is present on the film surface, it gives a sticky feel when made into a bag, which is undesirable. . In addition, the films tend to adhere to each other easily, causing a blocking phenomenon. As a result of further intensive research into improving the cloud-proofing properties of the polyethylene film proposed earlier, the present inventors found that the above-mentioned drawbacks can be overcome by using two or more types of fatty acid polyhydric alcohol esters with different numbers of carbons. We have learned that all of these problems can be solved, and have completed the present invention. That is, the gist of the present invention is that, for each part by weight of polyethylene 10, 'B' is an inorganic filler with an average particle size of 1 to 10 mm and a particle size of 0.1 to 15 mm.
．． 01 to 1 part by weight, 2) 0.05 to 5 parts by weight of an unsaturated fatty acid amide with a melting point of 90 qo or less, and ■ 8 to 8 carbon atoms.
A polyethylene resin composition containing 0.01 to 6 parts by weight of a mixed fatty acid polyhydric alcohol ester derived from a C20 fatty acid, a C21 to C35 fatty acid, and a polyhydric alcohol is extruded in a molten state from a molding machine. , 50q○ or less and solidifying the polyethylene film.

The present invention will be explained in detail below.

Polyethylene A of the polyethylene composition of the film material in the present invention is an ethylene homopolymer produced by a medium-low pressure method or a high-pressure method, or a copolymer with ethylene in a predominant amount and Q-olefin other than ethylene, vinyl acetate, etc. Also included are combinations or blended products containing a predominant amount of these.

Among these, melt index (hereinafter referred to as MI)
The MIO. 8-4, MIO. 4
~2 and a flow rate ratio (FR) of 35 or less is preferred. Inorganic filler B to be added to polyethylene includes silica,
There are powders of calcium carbonate, calcium sulfate, zeolite, feldspar, etc., and these have an average particle size of 1 to 10 mm and a particle size of 0.1 to 15 r.

If the size is outside the above range, the anti-blocking properties will be poor, and if it is too large, the so-called outer surface blocking phenomenon will occur, in which the films stick to each other when wound into a roll, which is undesirable. The unsaturated fatty acid Amamide C blended into polyethylene must have a melting point of 9000 or less, and specific examples thereof include oleic acid amide, erucic acid amide, ricinoleic acid amide, and the like.

If the melting point of these amides is higher than 90qC, the bleed rate when cooling and solidifying the molten resin and forming it into a film will be too fast, forming a liquid bottle shape on the film surface and condensing, resulting in a sticky feel to the film. In addition, the slippage of the film itself becomes poor. The mixed fatty acid polyhydric alcohol ester D blended into polyethylene has a carbon number of 8 to 20.
It is a mixed fatty acid polyhydric alcohol ester derived from fatty acid a, fatty acid b having 21 to 35 carbon atoms, and polyhydric alcohol.

Such esters may be monoesters, diesters, or esters, or may be mixtures thereof.
Specifically, polyhydric alcohol esters derived from fatty acids having 8 to 20 carbon atoms belonging to group a include polyglycerol monopalmitate, sorbitan monolaurate, sorbitan monopalmitate,
Sorbitan somonostearate, sorbitan monooleate, solpitan dilaurate, solpitan trioleate, and the like.

Furthermore, other fatty acids that form such esters include:
Cabrylic acid, capric acid, myristic acid, arachidic acid, octenoic acid, dodecenoic acid, icosenoic acid, undecic acid, tallylic acid, hexane-1,6-dicarboxylic acid, octane-1,8-dicarboxylic acid, undecane-1,11-
Examples include dicarboxylic acid, tetradecane-1,14-dicarboxylic acid, octadecane-1,18-dicarboxylic acid, and 2-butene-1,4-dicarboxylic acid. Polyhydric alcohol esters derived from fatty acids having 21 to 35 carbon atoms belonging to group b include sorbitan noerucate,
Examples include sorbitan monobehenic acid ester, glycerin gellicate ester, polyglycerin monobehenic acid ester, and sorbitan trinic acid ester.

Furthermore, other fatty acids that form such esters include n
-henicosanoic acid, lignoceric acid, cerotic acid, montanic acid, melisic acid, n-hentriacontanoic acid, celloplastic acid, docosenoic acid, mycoberic acid, behenolic acid, nadecane-1,19-dicarboxylic acid, docosan-1,22-dicarboxylic acid, dotoria contin-1,3
Examples include 2-dicarboxylic acid. As a mixture of each fatty acid belonging to the above-mentioned groups a and b, there is wool fatty acid as a natural product.

Wool fatty acids are mixed fatty acids obtained by hydrolyzing orchids (also called wool fat or wool wax). Lanolin is obtained by separating and refining fatty secretions attached to wool using soap or solvent, and is an ester of various complex fatty acids and monohydric higher alcohols. The composition of wool fatty acids varies depending on the grade, but usually 60 to 9% by weight of fatty acids with 8 to 20 carbon atoms and 21 carbon atoms.
Since the wool fatty acid contains 40 to 1% by weight of fatty acid B component of ~35, the wool fatty acid is esterified with an appropriate polyhydric alcohol to obtain a mixed fatty acid polyhydric alcohol ester suitable for use in the present invention. be able to. Examples of synthetic products include synthetic mixed fatty acids obtained by subjecting an olefin mixture containing an olefin having 7 to 19 carbon atoms and an olefin having 20 to 34 carbon atoms in a predetermined ratio to an oxo reaction and an oxidation reaction. The composition can be adjusted to a desired value by adding a fatty acid having a predetermined number of carbon atoms to these natural or synthetic mixed fatty acids depending on the purpose.

As the polyhydric alcohol for preparing the mixed polyhydric alcohol ester, alcohols having a valence of 2 or more, preferably alcohols having a valence of 3 or more are used.

Specifically, glycerin, polyglycerin, sorbitan,
Examples include trimethylolpropane, bentaerythritol, neobentyl glycol, ethylene glycol, propylene glycol, 1,4-butanediol, polyethylene glycol, polypropylene glycol, and the like. The difference in the average carbon numbers of the fatty acids a and b is 5 or more,
Preferably it is 8 or more, and if the difference is 4 or less, the film will feel sticky, which is not preferable.

Furthermore, if the proportion of a is too large, the film will feel sticky, and even if the proportion of b is increased, the anti-bleeding properties will be saturated, so it is uneconomical to increase the proportion. Therefore, mixed fatty acid polyhydric alcohol ester D is composed of a and b for fatty acid a having 8 to 20 carbon atoms and fatty acid b having 21 to 35 carbon atoms.
It is desirable that the difference in the average number of carbon atoms of the fatty acids is 5 or more, and the ratio of a and b is 60 to 9% by weight for a and 40 to 1% by weight for b.

The blending ratio of each of the above compounds is based on the weight part of the polyethylene resin AIOO and the inorganic filler BO. 01 to 1 part by weight, unsaturated fatty acid amide CO. 05-5 parts by weight, mixed fatty acid polyhydric alcohol ester DO. 01 to 6 parts by weight,
By selecting the blending amount within this range, it is possible to achieve a good balance between overall transparency and anti-blocking properties, which are contradictory.

If the amount of inorganic filler B is less than the above range, anti-blocking properties will not be imparted, while if it is too large, the transparency of the film will decrease, which is not preferable.

If the amount of unsaturated fatty acid Aamide C is less than the above range, lubricity will not be imparted, whereas if it is too much, a large amount will bleed onto the film surface, making the entire film look whitish and impairing transparency, which is not preferable. If the blending amount of mixed fatty acid polyhydric alcohol ester D is less than the above range, the cloud-proofing property will be poor, and if it is more than the range listed in L, the cloud-proofing property and anti-bleeding property will be saturated, and adding more than that is uneconomical and is preferable. do not have.

In the polyethylene composition of the present invention, in addition to the above-mentioned essential components, commonly used additives such as ultraviolet absorbers and heat stabilizers can be appropriately blended. The above-mentioned various compounds can be mixed with polyethylene by melt-mixing at 160 to 230 qo using a commonly used method, such as a Banbury mixer, a continuous mixer, or a kneading extruder.

Alternatively, a masterbatch containing a high concentration of additives may be prepared by a so-called masterbatch method, and this may be mixed with polyethylene at the time of film forming. In the method of the present invention, the polyethylene composition prepared as described above is melt-extruded using an extruder, and the resulting thin film-like molten resin is rapidly cooled.
solidify. The film may be formed by any method as long as it can rapidly cool and solidify the molten resin, but the inflation method and T-die method are particularly preferred.
The molding temperature is preferably above the melting point of the polyethylene resin and below 270 qo, particularly from 160 to 240 qo. Rapid solidification in the method of the present invention means that the film-like molten resin extruded at the above-mentioned molding temperature has a molecular weight of 5,000 or less, preferably 10 to 40
qo, particularly preferably 15 to 3500, refers to rapid cooling by contacting with a cooling medium. Due to this cooling, the solvent resin extruded from the die is
Usually within 10 seconds, preferably within 0.1 to 5 seconds,
Its surface temperature is cooled to below 50 oo. To rapidly cool the product to such a low temperature, there is a water-cooling method in which the product is immersed in water at a temperature within the above range, or a forced cooling method using a chill roll, mandrel, etc. that is kept at a temperature within the above range. In particular, the method using Mizubaki is preferred.
The method explored in normal film forming, that is, after extrusion,
If a slow cooling method such as air cooling is investigated, it takes a long time of one minute or more to cool down to room temperature, resulting in so-called slow cooling, and the resulting film has insufficient transparency. The film temperature is measured, for example, by a non-contact infrared radiation thermometer (IT Hime type) manufactured by Nippon Burns. In the method of the present invention, the thickness of the film is usually 20 to 150 mm, preferably 30 to 100 mm. The film obtained as described above has a synergistic effect due to the combination of the types of additives, the amount added, and the requirements of the molding method, and the contradictory properties of transparency and anti-blocking properties are compatible in a well-balanced manner. The film is particularly suitable for manufacturing packaging bags.

Next, Examples and Comparative Examples of the present invention will be shown.

In these examples, parts are parts by weight. Further, MI is melt index, p is density, and Tm is melting point. Example 1 The following formulation was used.

Wind Polyethylene resin Low density polyethylene Manufactured by Mitsubishi Chemical Industries, Ltd. Product name Novatec L F540 (Skin 3, p=0.931
) [B} Inorganic filler silica powder Manufactured by John Manville Co., Ltd. Product name: SF (Average particle size: 4 French, Particle size: 1 to 10 French) Unsaturated fatty acid amide: Oleic acid amide Product name: Diamid, manufactured by Nippon Kasei Co., Ltd. 0200 (Tm=76℃) ■Mixed fatty acid polyhydric alcohol ester: Wool fatty acid monoglycerin ester manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Product name Lamicite M20 (The carbon number distribution of wool fatty acid is 8 to 20 carbon atoms. Fatty acid a 83.0%, average carbon number 10 Fatty acid b 17.0%, average carbon number 21-35, average carbon number 24) In the above formulation, inorganic filler B, unsaturated fatty acid amide C, mixed fatty acid for the polyethylene resin AIOO portion 0.1 part of each polyhydric alcohol ester ○ was blended.

The mixture was mixed in a Banbury mixer at 160° C. and formed into pellets, and the pellets were fed to the following water-cooled inflation molding machine to form a film of 30-1 under the following conditions, and its physical properties were measured. The results are summarized in Table 1 along with the following Examples and Comparative Examples. The film forming machine, its forming conditions, and cooling conditions are as follows. ○) Molding machine: DTK-SO type water-cooled blown film molding machine manufactured by Kawada Seisakusho, screw diameter 50◇, screw L/D=
20 die diameter 75? , Digit gear knob 0.75 ribs, ■
Molding conditions: Resin temperature 22,000, take-up speed 20 m/min, 20 feet directly below the frost line die, blow ratio 1.7 Cooling conditions:
The time required from the die extrusion outlet to the water tank inlet is 1 second, the cooling water temperature is 2000 (inlet), 21°C (outlet), the film temperature at the cooling water tank outlet is 45oo, and the water tank passage time is 3 seconds. Cloudiness degree, blocking degree,
The degree of slippage, degree of stickiness, and cloud resistance were measured.

These characteristics were measured by the following method. m Cloudiness: Measured in accordance with ASTM D-1003-5 and expressed in haze.

■ Blocking degree: Two sheets of film after molding are stacked, dimensions 12 skin x 10
Apply a pressure of 50 pm/earth to the arc and leave it in an atmosphere of 50 pm for 24 hours, then heat it for 20 pm (RH 60%).
) was left in a constant temperature bath for more than a day and night, and the green part was removed from both sides by 1 c to make an adhesive surface of 10 skins x 10 additions, and the maximum strength when peeled off (T'I00) was measured. do.

The pulling rate is 5 m/min. A tensile testing machine (UTM-4 or Yama) is used for this measurement. '3' Sliding degree: 6 using Toyo Seiki's friction angle tester.
．． Attach it to a sled with a base of 3 pine x IQ pine, fix the same film on the slope, tilt the slope to find the angle 0 at which the sled starts sliding, and calculate the tangent.
) is indicated by a value of 0.

[41 Stickiness level: Measured by scale peel strength test.

Lightly overlap the two films in the temperature tank at 20:00,
The force required to peel off the two films within 5 minutes by applying pressure 3 times with a roll of 25 sides and 150 mm width at a linear pressure of 0.3 k9' (k9/yo)
is measured using an Instron type tensile tester.

The pulling speed was 30 mm/min, the chuck interval was 5 mm, the width of the sample film was 25 sides, and the contact area was 25 sides x 25 skins.

'5} Cloud resistance: 100 [Pour 70 degrees of hot water at 50 degrees Celsius into a beaker, cover the film with it, and leave it in a room at room temperature 21 degrees Celsius for 20 minutes. Score as shown below.

Example 2 A polyethylene film was produced in the same manner as in Example 1 except that the amount of inorganic filler B was changed to 0.7 parts.

Example 3 A polyethylene film was produced in the same manner as in Example 1 except that the amount of unsaturated fatty acid amide C was changed to 4 parts.

Example 4 A polyethylene film was produced in the same manner as in Example 1 except that the amount of mixed fatty acid polyhydric alcohol ester D was changed to 5 parts.

Example 5 The same procedure as Example 1 was carried out except that the amount of inorganic filler B was changed to 0.05 part.

Example 6 The same procedure as Example 1 was carried out except that the amount of unsaturated fatty acid amide C was changed to 0.06 parts.

Example 7 The amount of mixed fatty acid polyhydric alcohol ester D was adjusted to o. 0
The procedure was the same as in Example 1 except that the volume was changed to 5 parts.

Example 8 High-density polyethylene as polyethylene resin A [manufactured by Mitsubishi Chemical Industries, Ltd., trade name: Novatec EROI]
The same procedure as in Example 1 was carried out except that 0.0, MI 0.9 density 0.956] was used.

Example 9 Sorbitan monopalmitate ester (fatty acid having 16 carbon atoms) as mixed fatty acid polyhydric alcohol ester D {a
The same procedure as in Example 1 was carried out except that 0.1 part of a blend of sorbitan monobehenic acid ester (a fatty acid having 22 carbon atoms) (b}7 by weight) was added.

Example 10 Erucic acid amamide as unsaturated fatty acid amamide C [manufactured by Nippon Kasei Co., Ltd., trade name Diamid L200, melting point 86
00] was used in the same manner as in Example 1.

Comparative Example 1 A polyethylene composition having the same composition and blending amount as in Example 1 was used, but the film was formed by an air cooling method.

The molding was carried out at the same die temperature as in Example 1 using an EA-4 mold (screw diameter 400) manufactured by Modern Machinery Co., Ltd. as the equipment used. In this case, it took about 1 minute for the temperature of the extruded molten resin to reach 60:00. Comparative Example 2 Same as Example 1, but the amount of inorganic filler B was changed to 0.
005 copies.

Comparative Example 3 Same as Example 1, but as inorganic filler B, silica (manufactured by Taki Kagaku Co., Ltd.,
0.1 part of VitaSeal (trade name) was used.

Comparative Example 4 The same as Example 1, but with the following points, that is, the average particle size of the inorganic filler 8 is 0.05 mm, and the particle size is 0.01~
5. The formulation was changed to include 0.1 part of Hakuenka AA, manufactured by Calcium Carbonate Co., Ltd. (trade name).

Comparative Example 5 The same as Example 1 was used, but the amount of unsaturated fatty acid amide C was changed by one anchor.

Comparative Example 6 The same procedure as in Example 1 was carried out except that 0.1 part of sorbitan monobehenic acid ester (fatty acid having 22 carbon atoms) was added instead of mixed fatty acid polyhydric alcohol ester (○).

Comparative Example 7 The same procedure as in Example 1 was carried out except that 0.1 part of sorbitan monostearate (fatty acid having 18 carbon atoms) was added instead of mixed fatty acid polyhydric alcohol ester D.

Comparative Example 8 As mixed fatty acid polyhydric alcohol ester D, sorbitan monobehenic acid ester (fatty acid having 22 carbon atoms) {b
The same procedure as in Example 1 was carried out except that 0.1 part of a blend of sorbitan monomontanate ester (fatty acid having 28 carbon atoms) 'b}3 and sorbitan monomontanate ester (fatty acid having 28 carbon atoms) 'b}3 was added.

Comparative Example 9 Sorbitan monomyristic acid ester (fatty acid with 14 carbon atoms) as mixed fatty acid polyhydric alcohol ester D {a
}7% by weight and sorbitan monoicosanoate (
The same procedure as in Example 1 was carried out except that 0.1 part of a blend of C20 fatty acid)'a}3 by weight was added.

Comparative Example 10 Sorbitan monooctadecanoate ester (fatty acid with 18 carbon atoms) as mixed fatty acid polyhydric alcohol ester D
The procedure was the same as in Example 1, except that 0.1 part of a blend of % by weight of [a} 7 and % by weight of sorbitan monoicosanoic acid ester (fatty acid with 20 carbon atoms) 'b' 3 was added. Ta.

Comparative Example 11 The same procedure as in Example 1 was carried out except that the amount of mixed fatty acid polyhydric alcohol ester D (monoglycerin ester of wool fatty acid) was changed to 10 parts.

Comparative Example 12 Same as Example 1, but the amount of unsaturated fatty acid amide C was changed to 0.03 parts.

Comparative Example 13 Same as Example 1, but instead of oleic acid amide of unsaturated fatty acid amide C, methylene bisstearylamide with a melting point of 138°C [manufactured by Nippon Kasei Co., Ltd., Diamid 200 Bis] 0.1 section was used.

Comparative Example 14 The same procedure as in Example 1 was carried out, but the amount of mixed fatty acid polyhydric alcohol ester D was changed to 0.005 parts.

Comparative example 15 The procedure was as in Example 1 except for the following points.

That is, the polyethylene resin composition having the composition described in Example 8 was used, and the same molding machine as in Comparative Example 1 was used for film molding, and air cooling molding was performed under the same conditions. Comparative Example 16 The same procedure was used as in Example 1, except that ethylene bisstearylamide (manufactured by Nippon Kasei Co., Ltd., trade name: Lupron ES, melting point 13,800) having a melting point of 130 to 14,500 was used as the unsaturated fatty acid amamide C.

Comparative Example 17 The high-density polyethylene used in Example 8 was made into a film using the air-cooled film forming machine used in Comparative Example 1 without adding any additives.

Comparative Example 18 The high-density polyethylene used in Example 8 was made into a film using the water-cooled film forming machine described in Example 1 without adding any additives.

The measurement results of various properties of Examples 1 to 10 and Comparative Examples 1 to 18 are summarized in Table 1.

In Table 1 below, examples are abbreviated as "actual" and comparative examples are abbreviated as "ratio."

Table 1 Example 11 The same procedure as Example 1 was carried out except that the cooling water temperature was 5°C.

Example 12 The same procedure as in Example 1 was conducted except that the cooling water temperature was 50 qo.

Comparative Example 19 The same procedure as in Example 1 was conducted except that the cooling water temperature was 80 qo.

The degree of cloudiness, degree of blocking, degree of slippage, degree of stickiness, and cloud resistance of the films obtained in Examples 11 and 12 and Comparative Example 19 were measured in the same manner as in Example 1.

The results are shown in Table 2 below. In Table 2, Examples are actual,
Comparative examples are abbreviated as ratio. The results of Example 1 are also listed for reference. As is clear from Table 2, the film whose surface temperature was rapidly cooled to 50 qC or less within 1 inch of sand had good cloudiness, blocking, slippage, and stickiness.

On the other hand, when about 6 mouse sands were required for cooling (Comparative Example 19), the cloudiness was not improved. What has been explained above and mentioned in the examples is related to typical examples to help the understanding of the present invention, and the present invention is not limited to these examples, but may include other modifications and variations within the gist of the invention. Changes can be explored.

Claims (1)

[Claims] 1 (A) based on 100 parts by weight of polyethylene, (B)
0.01 to 1 part by weight of an inorganic filler with an average particle size of 1 to 10 μm and a particle size of 0.1 to 15 μm, (C) 0.05 to 5 parts by weight of an unsaturated fatty acid amide with a melting point of 90° C. or less, and (D) A polyethylene resin composition containing 0.01 to 6 parts by weight of a mixed fatty acid polyhydric alcohol ester derived from a fatty acid having 8 to 20 carbon atoms, a fatty acid having 21 to 35 carbon atoms, and a polyhydric alcohol is melted from a molding machine. extruded at 50℃
A method for producing a polyethylene film, which is characterized by rapidly cooling and solidifying the film. 2 Claims in which the mixed fatty acid polyhydric alcohol ester (D) consists of 60 to 90% by weight of fatty acid polyhydric alcohol ester having 8 to 20 carbon atoms and 40 to 10% by weight of fatty acid polyhydric alcohol ester having 21 to 35 carbon atoms 2. The method for producing a polyethylene film according to item 1. 3 Claim 1 in which the mixed fatty acid polyhydric alcohol ester (D) is a mixed fatty acid monoglycerin ester
A method for producing a polyethylene film as described in Section 1. 4. The method for producing a polyethylene film according to claim 1, which comprises extruding the polyethylene film in a molten state from a molding machine and rapidly cooling it to 50° C. or less within 10 seconds to solidify it by water cooling.