KR102627112B1 - Method for producing polyethylene resin film - Google Patents

Abstract

The object of the present invention is to efficiently and stably manufacture a polyethylene-based resin film that has excellent heat sealing properties and also has excellent appearance and scratch resistance.
In order to solve the above problems, the method for producing a polyethylene-based resin film of the present invention includes a process of melt-kneading particles made of polyethylene-based resin and a polyethylene resin composition containing a polyethylene-based resin, and melt-extruding the polyethylene resin composition to form molten polyethylene. It includes a step of forming a resin composition sheet, cooling and solidifying the molten polyethylene resin composition sheet, and a step of filtering the polyethylene resin composition using a filter with a filtration accuracy of 100 μm or less in the step of melt-kneading the polyethylene resin composition.

Description

Method for producing polyethylene resin film

The present invention relates to a method for producing a polyethylene-based resin film. More specifically, it relates to a method of manufacturing a polyethylene-based resin film that has excellent stable blocking resistance or stable sliding properties, and also has excellent appearance and scratch resistance.

Recently, packaging or containers using films have been used in a wide range of fields due to convenience, resource saving, and reduced environmental load. Compared to conventional molded containers and molded products, films have the advantage of being lightweight, easy to dispose of, and low cost.

For example, sealant films are generally used by lamination with base films such as biaxially stretched nylon film, biaxially stretched ester film, and biaxially stretched polypropylene film, which have lower low-temperature heat adhesiveness than sealant films. If stored in roll shape after lamination with these base films, blocking may occur between the sealant film and the base film, making it difficult to rewind the laminated film before bagging processing, or the sealant that becomes the inner surface of the bag during bundling processing. There were cases where blocking occurred between films, making it difficult to fill food.

Accordingly, a method of avoiding blocking between the sealant film and the base material or between sealant films as described above is known by sprinkling powder such as starch on the surface of the sealant film.

However, this measure not only contaminates the area around the film processing equipment, but also significantly deteriorates the appearance of the packaged food, or the powder attached to the sealant film is mixed directly into the package along with the food, or the heat sealing strength is reduced. It was causing a problem.

Accordingly, a polyethylene-based resin film using inorganic fine powder or inorganic particles such as silica in the polyethylene-based resin has been reported (for example, see Patent Document 1).

However, in the case of this measure, scratches are likely to occur when the film surfaces containing inorganic fine powder or inorganic particles such as alumina or silica added to the polyethylene film are rubbed against each other, and laminating machines or umbilical processing machines are used with sealant films or substrates. There was also a problem that inorganic fine powder or inorganic particles tend to fall off when the laminate with the film passes through and comes into contact with a part of the machine (see, for example, Patent Document 1).

Additionally, a polyethylene-based resin film using organic crosslinked particles made of a copolymer containing acrylic monomers and styrene-based monomers as main components has been reported (see, for example, Patent Document 1).

However, in the case of this measure, the ease of creating scratches is not as bad as that of inorganic particles, but it cannot be said to be sufficient. In addition, problems with blocking resistance and particle dropping still remained.

In addition, when the polyethylene raw resin composition is melt-kneaded and extruded to form a sheet, it is essential for quality control to filter the cross-linked organic matter, so-called gel, generated as a result of decomposition and recombination of the polyethylene resin using a filter. At this time, if the inorganic particles or cross-linked organic particles aggregate and clog the filter, the filter must be replaced, which causes problems such as lowering the operating efficiency and increasing the cost. Additionally, if extrusion speed is given priority and a filter with low filtration precision is used, the so-called gel removal is insufficient, and there is a problem in that gel defects increase over time and quality deteriorates.

Japanese Patent Publication No. 10-86300

The purpose of the present invention is to efficiently and stably produce a polyethylene-based resin film that has excellent heat sealing properties, appearance, and scratch resistance, and also has minimal particle falloff.

In view of this actual situation, the present inventors have conducted intensive studies and discovered that the above-mentioned problem can be solved by using particles made of polyethylene resin and producing a polyethylene resin film using a filter with high filtration accuracy, We have come to the solution of invention.

That is, the present invention includes a process of melt-kneading particles made of polyethylene resin and a polyethylene resin composition containing a polyethylene resin, a process of melt-extruding the polyethylene resin composition to form a molten polyethylene resin composition sheet, and cooling the molten polyethylene resin composition sheet. A method for producing a polyethylene-based resin film, including a step of solidifying, and in the step of melting and kneading the polyethylene resin composition, a step of filtering using a film with a filtration accuracy of 100 ㎛ or less.

In this case, it is suitable that the particles made of the polyethylene resin have a viscosity average molecular weight of 1.5 million or more and a melting point peak temperature by DSC of 150°C or less.

Also, in this case, it is suitable that the filtration accuracy of the filter is 80 μm or less.

According to the present invention, a polyethylene-based resin film that has excellent heat sealing properties and also has excellent appearance and scratch resistance can be efficiently and stably manufactured.

(Particles made of polyethylene resin)

The particles made of polyethylene resin in the present invention preferably have a viscosity average molecular weight of 1.5 million or more, more preferably 1.6 million or more, and still more preferably 1.7 million or more. Additionally, it is preferably 2.5 million or less, more preferably 2.4 million or less, and even more preferably 2.3 million or less.

If the viscosity average molecular weight is within this range, the maximum acid height of at least one surface layer of the obtained film can be 2 μm or more and 15 μm or less. The reason is not clear, but since the difference in molecular weight between the particles made of polyethylene resin and the polyethylene resin other than the particles made of polyethylene resin is very large, the molecules do not mix, and even in the film obtained by melt mixing and extrusion, polyethylene Since it is easy to maintain the shape of particles made of resin, and agglomeration due to fusion or adhesion between particles is difficult to occur, it is assumed that protrusions corresponding to the particle size can be formed on the surface of the film, similar to inorganic particles. there is.

If the viscosity average molecular weight of the particles made of polyethylene resin is less than 1.5 million, if the temperature at the time of melt mixing is higher than the melting point peak, the particle shape may change due to decomposition or fusion agglomeration due to heat or shear or partial compatibility with the base resin. Because changes occur, it becomes impossible to form protrusions like conventional inorganic particles or organic crosslinked polymer beads, and not only does the function as an anti-blocking agent become insufficient, but it also affects the appearance such as transparency, the mechanical strength of the film, or heat sealing properties. It's crazy.

Additionally, if the viscosity average molecular weight exceeds 2.5 million, it becomes easy to maintain the particle shape when melting, mixing, and extruding to form a film, but in that case, it tends to become difficult to form suitable film surface protrusions.

Also, this is surprising: although particles made of polyethylene resin with a viscosity average molecular weight of 1.5 million or more have the property of being difficult to aggregate, they have the characteristic of being less likely to fall off from other polyethylene resins mixed with them than inorganic particles. I knew I had it.

In addition, if the viscosity average molecular weight of the particles made of polyethylene resin is 1.5 million or more, the particles themselves have lubricity, which contributes to improving blocking resistance and slipperiness. Additionally, since the particles made of polyethylene resin are soft, scratch resistance is also improved. I think so.

The average particle diameter of the particles made of polyethylene resin used in the present invention is preferably 2 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more. Additionally, the average particle diameter is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

In addition, it is preferable that it does not contain particles with a particle size of 25 ㎛ or more. Even if the average particle diameter is 20 μm or less, if 1% or more of particles with a particle diameter of 25 μm or more are included, the maximum peak height on the film surface tends to exceed 15 μm. Then, when the film surface is observed with the naked eye, flicker, which will be described later, occurs.

Additionally, particles larger than 25 μm are undesirable because they cause defects and reduce quality.

(polyethylene resin)

Polyethylene-based resins other than “particles made of polyethylene-based resin” in the present invention include homopolymers of ethylene monomer, copolymers of ethylene monomer and α-olefin, and mixtures thereof, and examples of α-olefin include propylene and butene-1. , hexene-1, 4-methylpentene-1, octene-1, decene-1, etc.

There is no particular limitation on the density range of the polyethylene-based resin other than the particles made of polyethylene-based resin in the present invention, but in order to obtain a polyethylene-based resin film that has both heat sealability and blocking resistance, 900 to 940 kg/m3 is preferable. , 905 to 935 kg/m3 is more preferable, 910 to 930 kg/m3 is still more preferable, and 915 to 925 kg/m3 is particularly preferable. Polyethylene-based resins with a density of less than 900 kg/m3 tend to have reduced blocking resistance.

Polyethylene-based resins with a density greater than 940 kg/㎥ have a high heat sealing start temperature, making it difficult to process them, and have poor transparency. However, when polyethylene-based resins with a density greater than 940 kg/㎥ are used, they can be used for packaging heavy items, etc. The present invention is very effective in producing a polyethylene-based resin film with excellent strength by reducing the filter replacement frequency or producing a film with few defects.

The blocking resistance was tested by pressurizing a sample with the measurement surfaces of the film overlapping each other in a heat press (model: SA-303 manufactured by Tester Sangyo Co., Ltd.) at a size of 7 cm x 7 cm, a temperature of 50°C, a pressure of 440 kgf/cm2, and a time of 15 minutes. Do. The sample and bar (diameter: 6 mm, material: aluminum) blocked by this pressure treatment were mounted on an autograph (model: UA-3122 manufactured by Shimadzu Corporation) so that the bar and the peeling surface were horizontal, and the bar moved at a speed (100 m/min). ), the force when peeling off the blocking part is measured 4 times, and the average value is used as an index. However, when polyethylene resin with a density greater than 0.940 g/㎥ is used, the measured value for each of the 4 measurements is likely to fluctuate. In addition, a tendency for the heat sealing initiation temperature to increase was confirmed. It is desirable that the variation of the measured value for each of the four measurements is at the same level as when using inorganic particles.

It is currently not clear why the measured values tend to fluctuate depending on the measurement sample, but when a high-density polyethylene resin is used as the base, the viscosity average molecular weight of the particles made of polyethylene resin decreases, or the polyethylene resin other than the particles made of polyethylene resin decreases. It is presumed that this is due to a change in particle size due to interlocking of the molecular chains, and as a result, the surface protrusions formed become more non-uniform.

For polyethylene-based resins other than particles made of the polyethylene-based resin of the present invention, the melt flow rate (hereinafter sometimes referred to as MFR) is preferably about 2.5 to 10 g/min from the viewpoint of film forming properties and the like. Here, MFR was measured based on JIS K7210. Alternatively, the polyethylene resin is synthesized using a known method.

In the case of using a resin with a low MFR of 2.5 g/10 min or less other than the polyethylene resin particles in the present invention, the viscosity average of the polyethylene resin particles is similar to the description for density. Since particle size changes are likely to occur due to a decrease in molecular weight or interlocking of molecular chains with polyethylene resins other than particles made of polyethylene resins, caution is required in extrusion conditions. In the case of high-speed film forming with a large film forming machine, an MFR of about 3 to 4 g/10 minutes is particularly preferable for film forming properties.

For polyethylene-based resins other than particles made of polyethylene-based resin in the present invention, the melting point is preferably 85°C or higher, more preferably 100°C or higher, and especially preferably 110°C or higher from the viewpoint of heat resistance and the like.

Polyethylene-based resins other than the particles made of polyethylene-based resin in the present invention may be of a single type, but it is also possible to mix two or more types of polyethylene-based resins having different densities in the above density range. When two or more types of polyethylene resins with different densities are blended, the average density and mixing ratio can be estimated by GPC measurement or density measurement.

As polyethylene-based resins other than the particles made of polyethylene-based resins with a density of 900 to 940 kg/m3 as described above, high-pressure processed low-density polyethylene (LDPE) is transparent, has abundant flexibility, and has excellent tear strength and tensile strength on average. ), butene-1·hexene-1-octene-1 is copolymerized in small amounts to form linear short-chain branched polyethylene (LLDPE), which has many single molecules in the molecular chain and has excellent sealing performance and physical strength. It exhibits a very sharp molecular weight distribution, The distribution of comonomers is uniform, and metallocene-catalyzed linear short-chain branched polyethylene (LLDPE), which has excellent tear, tensile, puncture strength, and pin hole resistance properties, can be selected depending on the application.

The amount of particles made of polyethylene resin added in the present invention is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and even more preferably 0.4% by weight or more based on the entire film. Additionally, 2% by weight or less is preferable, 1.5% by weight or less is more preferable, and 1.0% by weight or less is still more preferable. If the amount of particles made of polyethylene resin added is less than 0.1% by weight, it becomes difficult to set the maximum ridge height of at least one surface layer of the obtained film to 2 ㎛ or more per designated area (0.2 ㎟), making it difficult to obtain anti-blocking properties and slipperiness. Lose. Additionally, if the amount of particles made of polyethylene resin added is more than 2% by weight, surface protrusions increase, transparency is poor, and low-temperature sealing properties tend to be poor.

In the polyethylene-based resin film in the present invention, known additives such as antioxidants, neutralizers, organic lubricants, anti-dropping agents, and antistatic agents may be used in combination within the range that does not impair the purpose and effect of the present invention. These additives can be appropriately blended when blending and mixing each component of the polyethylene resin composition.

It is preferable to add an organic lubricant to the polyethylene-based resin film in the present invention. The slipperiness and anti-blocking effect of the laminated film are improved, and the handling of the film improves. The reason for this is believed to be that the organic lubricant bleeds out and exists on the film surface, resulting in the lubricant effect and release effect. Additionally, it is preferable to add an organic lubricant that has a melting point above room temperature. Organic lubricants include fatty acid amides and fatty acid esters. Specifically, they include oleic acid amide, erucic acid amide, behenic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, and ethylenebisoleic acid amide. Although these may be used individually, it is preferable to use two or more types together because slipperiness and anti-blocking effects can be maintained even under extremely harsh environments.

The lower limit of the concentration of the organic lubricant amide in the film of the present invention or in the layer containing particles made of polyethylene resin is preferably 200 ppm, more preferably 400 ppm. If it is less than the above, slipperiness may deteriorate. The upper limit of the organic lubricant amide concentration is preferably 2,500 ppm, more preferably 2,000 ppm. If it exceeds the above, it becomes too slippery and is not desirable.

Additionally, ethylene/vinyl acetate copolymer, ethylene/acrylic acid ester copolymer, etc. may be mixed and used as long as they do not impair the purpose and effect of the present invention.

In the polyethylene resin film in the present invention, it is necessary to contain substantially no inorganic particles. When inorganic particles are substantially contained, not only does it become difficult to obtain the effects of adding particles made of polyethylene resin, such as scratch resistance and particle fall-off, but also when a filter with high filtration accuracy is used, the filter pressure boost is increased. It is fast, and operation efficiency decreases due to filter replacement. The inorganic particles referred to herein are inorganic substances generally used as anti-blocking agents such as silica, talc, calcium carbonate, diatomaceous earth, and zeolite. Substantially not containing them means that the amount of inorganic particles in the entire polyethylene resin film of the present invention is It means that the ratio is 0.2% by weight or less. More preferably, it is 0.1% by weight or less.

In the polyethylene-based resin film in the present invention, it is necessary to contain substantially no crosslinked organic particles. When crosslinked organic particles are substantially contained, it becomes difficult to obtain the effects of adding particles made of polyethylene resin, such as scratch resistance and preventing particles from falling off. The crosslinked organic particles referred to herein are crosslinked particles represented by polymethyl acrylate resin, etc., and substantially not containing them means that the amount of crosslinked organic particles in the entire polyethylene resin film of the present invention is 0.2% by weight or less. do. More preferably, it is 0.1% by weight or less.

(Method of unveiling)

As a method for producing a polyethylene-based resin film of the present invention, for example, a step of melt-kneading a polyethylene-based resin composition containing particles made of polyethylene-based resin and polyethylene-based resins other than particles made of polyethylene-based resin, melt-kneading It is preferable to employ a process of melt-extruding the resin composition to form a molten resin composition sheet and a process of cooling and solidifying the molten resin composition sheet.

The polyethylene-based resin film in the present invention may be a single layer or a laminated layer. In the case of lamination, another layer different from the layer containing particles made of polyethylene resin and having a maximum acid height of at least one surface layer of 2 μm or more and 15 μm or less can be provided.

The thickness of the film in the case of a single layer is preferably 3 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and especially preferably 20 μm or more. Additionally, 200 μm or less is preferable, 150 μm or less is more preferable, and 100 μm or less is particularly preferable. In the case of less than 3 ㎛, the effect of the particles made of polyethylene resin is reduced, and the effects of blocking resistance and slipperiness are difficult to be expressed.

In the case of lamination, the thickness of the layer containing particles made of polyethylene resin and at least one surface layer having a maximum acid height of 2 ㎛ or more and 15 ㎛ or less is preferably 3 ㎛ or more, more preferably 10 ㎛ or more, and 15 ㎛. More than 20 μm is more preferable, and 20 μm or more is especially preferable. Additionally, 200 μm or less is preferable, 150 μm or less is more preferable, and 100 μm or less is particularly preferable. In the case of less than 3 ㎛, the effect of the particles made of polyethylene resin is reduced, and the effects of blocking resistance and slipperiness are difficult to be expressed.

(Raw material mixing process)

When mixing particles made of polyethylene resin and polyethylene resins other than particles made of polyethylene resin, any method is sufficient to ensure that they are mixed uniformly. If a masterbatch is used, a ribbon blender, Henschel mixer, tumbler mixer, etc. A method of mixing using . In the case of direct addition, particles made of polyethylene resin may be attached to the resin to which the additive is attached, or may be added directly to the extruder through a side feed or the like.

The method of using a small amount of a masterbatch made by mixing particles made of polyethylene resin at a high concentration with polyethylene resins other than particles made of polyethylene resin and mixing them with polyethylene resins other than particles made of polyethylene resin has a high dispersibility. Good and simple. However, when particles made of polyethylene resin are mixed directly with linear low-density polyethylene, a homopolymer of ethylene monomer, or a copolymer of ethylene monomer and α-olefin, without using a masterbatch, high dispersibility is obtained. In terms of cost, direct addition by a side feed method or the like is preferable.

(melt mixing process)

First, the particles made of polyethylene resin as a film raw material and the polyethylene resin other than the particles made of polyethylene resin are dried or hot air dried so that the moisture content is less than 1,000 ppm. Next, each raw material is measured, mixed, supplied to an extruder, and melted and kneaded.

The lower limit of the melt mixing temperature of the polyethylene resin composition obtained by mixing is preferably 200°C, more preferably 210°C, and still more preferably 220°C. If it is less than the above, discharge may become unstable. The upper limit of the melting temperature of the resin composition is preferably 260°C. If it exceeds the above, decomposition of the resin composition progresses, and the amount of foreign substances such as crosslinked organic substances, so-called gels, generated as a result of recombination increases.

When the polyethylene-based resin composition contains the antioxidant described above, melt extrusion at a higher temperature becomes possible, but the temperature is preferably 270°C or lower.

The melting point of the polyethylene-based resin particles used in the present invention is about 150°C or lower, and although it is much lower than the temperature at the time of melt kneading when mixed with polyethylene-based resins other than the polyethylene-based resin particles, surprisingly, “polyethylene” In the polyethylene-based resin film obtained by extruding from a T die and going through a cooling process without being dispersed at the molecular level in a polyethylene-based resin other than “particles made of polyethylene-based resin,” the particles made of polyethylene-based resin are other than the particles made of polyethylene-based resin. It exists while maintaining the particle size and shape before addition to the polyethylene resin.

(percolation)

In the melt kneading process, high-precision filtration can be performed to remove foreign substances contained in the molten polyethylene-based resin composition. The filter medium used for high-precision filtration of molten resin is not particularly limited, but in the case of a stainless steel sintered body, the main components include Si, Ti, Sb, Ge, and Cu derived from additives such as catalysts, in addition to foreign substances such as so-called gel. It is suitable as it has excellent removal performance of aggregates. Additionally, the filtration accuracy is preferably 100 μm or less, more preferably 80 μm or less, and particularly preferably 70 μm or less.

Since the particles made of polyethylene resin in the present invention are melted during melt kneading, not only is it impossible to filter them with a high-precision filter medium, but also the number of coarse particles is small, so the pressure increase due to clogging is less compared to inorganic particles. There is. In addition, by reducing the average particle diameter of the particles made of polyethylene resin or narrowing the particle size distribution, clogging is reduced and foreign substances can be removed, even when industrially produced with a high-precision filter medium with a filtration accuracy of 60 ㎛ or less, for example. In addition, there is an advantage that the blocking resistance obtained by particles made of polyethylene resin is not impaired.

The filtration accuracy referred to here is the nominal filtration accuracy, which has the ability to capture more than 60% of particles larger than the indicated filtration accuracy (for example, particles larger than 60 μm when the filtration accuracy is set to 60 μm). Absolute filtration accuracy is the performance of capturing more than 99.9% of particles larger than the indicated filtration accuracy, and even if it is a nominal filtration accuracy, it is desirable for the performance to be close to the absolute filtration accuracy.

(filter boost)

It is preferable that the amount of pressure increase during melt kneading of the polyethylene resin composition is small. The method of measuring the amount of pressure increase was performed by the method described in the Examples.

(melt extrusion process)

Next, the molten polyethylene resin composition sheet is melt-extruded from, for example, a T-shaped die, casted on a cooling roll, and cooled and solidified to obtain an unstretched sheet. As a specific method for this, casting on a cooling roll is preferable.

Since the particles made of polyethylene resin used in the present invention are hydrophobic resins from the beginning, the hydrophobicity of the surface of the particles does not change even after going through the melt kneading and extrusion processes, and the lip of the T-shaped die visible in the inorganic particles whose surface has been treated to make the surface hydrophobic is not changed. It is very difficult for thermal deterioration, or so-called eye mucus, to occur.

Examples include a method of melting and extruding a molten polyethylene resin composition sheet to form an object into a film using the T-die method or the inflation method. The T-die method is particularly preferable because the melting temperature of the resin composition can be increased.

(lip contamination)

When melt-extruding a polyethylene-based resin composition from a T-shaped die, it is preferable that the lip of the T-shaped die be less contaminated. The method of measuring lip contamination was performed by the method described in the Examples.

(Cooling solidification process)

For example, it is preferable to cool the molten sheet of the polyethylene resin composition melt-extruded from a T-shaped die by casting it on a cooling roll. The lower limit of the cooling roll temperature is preferably 10°C. If it is less than the above, the effect of suppressing crystallization may be saturated and problems such as condensation may occur, which is not desirable. The upper limit of the cooling roll temperature is preferably 70°C or lower. If the above amount is exceeded, the degree of crystallinity may become excessively high and the appearance may deteriorate. Additionally, when the temperature of the cooling roll is within the above range, it is desirable to lower the humidity of the environment near the cooling roll to prevent condensation.

In the case of casting, the temperature of the cooling roll surface rises because hot resin comes into contact with the surface. In addition, the cooling roll is cooled by flowing cooling water through internal piping. By securing a sufficient amount of cooling water, designing the arrangement of the piping, and performing maintenance to prevent sludge from adhering to the piping, the temperature difference in the width direction of the surface of the cooling roll is reduced. We need to do less. At this time, the thickness of the unstretched sheet is preferably in the range of 3 to 200 ㎛.

(Multi-layer composition)

The polyethylene-based resin film in the present invention may have a multilayer structure. In the case of a multi-layer, in addition to the layer containing particles made of the above-described polyethylene resin and having a maximum acid height of at least one surface layer of 2 μm or more and 15 μm or less, one or two or more other layers can be provided.

As a specific method of multilayering in this way, a general multilayering device (multilayer feed block, static mixer, multilayer multi-manifold, etc.) can be used.

For example, a method of stacking thermoplastic resins delivered from different flow paths using two or more extruders into multiple layers using a feed block, static mixer, multi-manifold die, etc. can be used. Additionally, it is also possible to introduce the above-described multilayering device into the melt line from the extruder to the T-type die using only one extruder.

In the case of a three-layer structure, the layer containing particles made of polyethylene resin and having a maximum acid height of at least one surface layer of 3 ㎛ or more and 15 ㎛ or less is used as a sealing layer (layer A), and the other layers are each an intermediate layer (layer B) ), the laminate layer (C layer), and it is better to have a configuration that includes them in this order.

The outermost layers are the A and C layers, respectively.

Examples of the polyethylene-based resin used in the intermediate layer (B layer) and laminate layer (C layer) include one or a mixture of two or more selected from ethylene/α-olefin copolymer and high-pressure polyethylene. . The ethylene/α-olefin copolymer is a copolymer of ethylene and an α-olefin having 4 to 18 carbon atoms, and the α-olefins include butene-1, hexene-1, 4-methylpentene-1, octene-1, and decene-1. etc. can be mentioned.

Films obtained from these polyethylene resins have excellent heat sealing strength, hot tack properties, contaminant sealing properties, and impact resistance, and the polyethylene resins can be used with other resins, such as ethylene/vinyl acetate, to the extent that these properties are not impaired. You may use a mixture of polymer, ethylene/acrylic acid ester copolymer, etc.

At this time, the polyethylene-based resin used for the intermediate layer (B layer) and the laminate layer (C layer) may be the same or different. Additionally, particles made of polyethylene resin may or may not be added. However, it is substantially free of inorganic particles and organic crosslinked particles. Substantially not containing it means that the amount of crosslinked organic particles in the entire polyethylene resin film of the present invention is 0.2% by weight or less. More preferably, it is 0.1% by weight or less.

In this case, it is preferable that the average density of the polyethylene resin in each layer of the film is sealant layer (A layer) ≤ intermediate layer (B layer) ≤ laminate layer (C layer). The blended organic lubricant is effective in maintaining slipperiness after lamination because it is difficult to move into high-density layers.

At this time, the lower limit of the density of the intermediate layer (B layer) and the laminate layer (C layer) is preferably 900 kg/m3, more preferably 920 kg/m3, and even more preferably 930 kg/m3. If it is less than the above, the rigidity is weak and processing may be difficult.

The upper limit of the density of the intermediate layer (B layer) and the laminate layer (C layer) is preferably 960 kg/m3, more preferably 940 kg/m3, and even more preferably 935 kg/m3.

The organic lubricant described above may be used in the intermediate layer (B layer) of the polyethylene resin film in the present invention, and the lower limit of the organic lubricant is preferably 200 ppm, more preferably 400 ppm. If it is less than the above, slipperiness may deteriorate.

The upper limit of the erucic acid amide concentration in the middle layer (layer B) is preferably 2,000 ppm, more preferably 1,500 ppm. If it exceeds the above, it may slip too much and cause misalignment of the winding.

10 to 30% by mass of recovered resin may be blended into the intermediate layer (layer B) of the polyethylene resin film in the present invention.

In the present invention, it is preferable to perform actinic ray treatment such as corona treatment on the laminate layer (C layer) surface of the polyethylene resin film described above. This response improves the laminate strength.

In the case of two layers, the layer containing particles made of polyethylene resin and having a maximum acid height of at least one surface layer of 3 ㎛ or more and 15 ㎛ or less is used as the sealing layer (A layer), and the other layer is used as the laminate layer (C layer). It's good to do it.

(maximum projection height)

It is necessary that the maximum acid height of at least one surface layer of the polyethylene resin film of the present invention is 2 μm or more and 15 μm or less. If the maximum acid height Rz exceeds 15 μm, it is undesirable because it causes appearance defects. The measurement method is carried out as described in the examples.

(Number of protrusions greater than 15 μ)

In the polyethylene-based resin film according to the present invention, the maximum peak height on the surface is preferably 2 ㎛ or more and 15 ㎛ or less, and the number of protrusions exceeding 15 ㎛ (piece/0.2 ㎟) in the surface layer is preferably 0 or less. The smaller the number, the worse the appearance of flicker or haze. The measurement method is performed by the method described in the examples.

(Heat sealing start temperature)

The upper limit of the heat sealing start temperature of a polyethylene resin film laminated with a biaxially stretched nylon film (15 μm) is preferably 130°C, more preferably 120°C. If it exceeds the above, sealing processing may become difficult. The measurement method is performed by the method described in the examples.

(Reach heat sealing strength)

The lower limit of the heat sealing strength achieved at 120°C of a polyethylene-based resin film laminated with a biaxially stretched nylon film (15 μm) is preferably 30 N/15 mm, and more preferably 35 N/15 mm. If it is less than the above, the bag may become easily damaged after discharge.

The upper limit of the heat sealing strength achieved at 120°C of a polyethylene-based resin film laminated with a biaxially stretched nylon film (15 μm) is preferably 70 N/15 mm, and more preferably 65 N/15 mm. If it exceeds the above, it may become difficult to open the bag after discharge. The measurement method is performed by the method described in the examples.

(Blocking strength)

The lower limit of the blocking strength of the polyethylene resin film laminated with a biaxially stretched nylon film (15 ㎛) is preferably 0 mN/20 mm, more preferably 10 mN/20 mm, and still more preferably 15 mN/20. It is mm.

The upper limit of the blocking strength is preferably 150 mN/20 mm, more preferably 50 mN/20 mm, and still more preferably 40 mN/20 mm. If the above is exceeded, the slipperiness immediately after unwinding may deteriorate. The measurement method is performed by the method described in the examples.

(Friction strength)

The lower limit of the coefficient of static friction after lamination of a polyethylene-based resin film obtained by laminating a biaxially stretched nylon film (15 μm) is preferably 0.05, more preferably 0.08. If it is less than the above, the film may slip excessively during winding, causing the film to be wound misaligned.

The upper limit of the coefficient of static friction after lamination is preferably 0.50, and more preferably 0.4. If it exceeds the above, openability after discharge may be poor and loss during processing may increase. The measurement method is performed by the method described in the examples.

(Hayes)

The lower limit of the haze of the polyethylene resin film of the present invention is preferably 3%, more preferably 4%, and still more preferably 5%. If it is less than the above, there is a risk that the anti-blocking agent is insufficient, which may cause blocking.

The upper limit of haze is preferably 15%, more preferably 12%, and still more preferably 10%. If it exceeds the above, it may become difficult to recognize the contents. The measurement method is performed by the method described in the examples.

(flicker feeling)

It is preferable that the polyethylene-based resin film of the present invention has almost no flicker, or has fine flicker but is uniform and does not cause particular concern. The measurement method is performed by the method described in the examples.

In the case of the so-called non-powder type, which has blocking resistance even without sprinkling powder such as starch on the film surface, there is a conventional type in which inorganic particles with an average particle diameter of about 10 ㎛ are added, but the flicker feeling may be poor.

(Scratch resistance)

A polyethylene-based resin film laminated with a biaxially stretched nylon film (15 ㎛) shows almost no scratches or fine stripe-shaped scratches but does not whiten even after picking it with the fingers and rubbing it 10 times so that the sealing surfaces overlap each other. desirable. The measurement method is performed by the method described in the examples.

In the case of the so-called non-powder type, which has blocking resistance even without sprinkling powder such as starch on the film surface, there is a conventional type in which inorganic particles with an average particle diameter of about 10 ㎛ are added, but the scratch resistance is poor.

(Young’s modulus)

The lower limit of the Young's modulus (TD) of the polyethylene resin film of the present invention is preferably 100 MPa, more preferably 200 MPa. If it is less than the above, the rigidity may be too weak and processing may be difficult. The upper limit of Young's modulus (TD) is preferably 800 MPa, more preferably 600 MPa.

The lower limit of Young's modulus (TD) of the polyethylene-based film of the present invention is preferably 100 MPa, more preferably 200 MPa. If it is less than the above, the rigidity may be too weak and processing may be difficult.

The upper limit of Young's modulus (TD) is preferably 1,000 MPa, more preferably 600 MPa.

Example

The present invention will be described in more detail below through examples and comparative examples, but the present invention is not particularly limited by the examples below. In addition, the measurement value of each item in the detailed description and examples of the present invention was measured by the method below.

Embodiments of the present invention will be described in detail below.

(1) Method for measuring particles made of polyethylene resin

For particles made of polyethylene resin, each physical property of the raw material resin was measured before processing.

In addition, even after forming the film, the film is dissolved at a temperature at which polyethylene other than the particles made of polyethylene resin are completely dissolved using decane as a solvent, and the residue is filtered through a filter with a filtration accuracy of 2 ㎛, or decane It is also possible to separate and measure the particles made of polyethylene resin by completely melting the particles in the medium and then separating the high molecular weight portion using GPC or the like.

(2) Viscosity average molecular weight of particles made of polyethylene resin

Measurement was made based on ASTM-D4020.

(3) Average particle size of particles made of polyethylene resin

The average particle diameter of the particles made of polyethylene resin before use was measured as follows.

The particles were dispersed in ion-exchanged water stirred at a predetermined rotation speed (approximately 5,000 rpm) using a high-speed stirrer, and the dispersion was added to isotone (physiological saline) and further dispersed using an ultrasonic disperser, followed by the Coulter counter method. The particle size distribution was obtained and calculated as the volume average particle diameter.

(4) Particle size distribution of particles made of polyethylene resin

Among the particles made of polyethylene resin before use, the proportion of those with a particle diameter of 25 μm or more was calculated from the particle size distribution obtained by the Coulter counter method.

(5) Melting point of particles made of polyethylene resin

The melting point of the particles made of polyethylene resin before use was measured using a differential scanning calorimeter (DSC) manufactured by SII at a sample amount of 10 mg and a temperature increase rate of 10°C/min. The melting endothermic peak temperature detected here was taken as the melting point.

(6) Density, MFR, melting point of polyethylene resin other than particles made of polyethylene resin

Each raw material before film forming was measured using the method below.

In addition, for polyethylene-based resins other than particles made of polyethylene-based resin, which form a layer containing particles made of polyethylene-based resin, the entire layer if single layer, or the layer composition if laminated is confirmed with an electron microscope, etc., and then the surface is made to a thickness less than the surface layer. It can be measured in the same way by removing the solvent from the filtered solution obtained in (1) above by cutting it with a . In the case of cutting from lamination, it can be done relatively easily by laminating a polyethylene terephthalate (PET) film or the like and then cutting it with a razor or the like.

(density)

It was measured using the density gradient tube method according to JIS-K7112.

(Mel flow rate: MFR) (g/10 minutes)

Measured at a temperature of 190°C in accordance with JIS-K7210.

(melting point)

Measurement was performed using a differential scanning calorimeter (DSC) manufactured by SII at a sample amount of 10 mg and a temperature increase rate of 10°C/min. The melting endothermic peak temperature detected here was taken as the melting point.

(7) Content of inorganic particles in the film (% by weight)

The content of the inorganic particles in the film was calculated from the amount added in the raw resin composition before processing.

In addition, even after forming the film, a method such as dissolving the film at a temperature where polyethylene other than the particles made of polyethylene resin is completely dissolved using decane as a solvent, and filtering the residue through a filter with a filtration accuracy of 2 ㎛, etc. It is also possible to separate and measure inorganic particles.

(8) Filter pressure boosting (film forming processability)

When the resin composition used in the sealing layer was discharged into a nythlon sintered filter with a filtration accuracy of 60 ㎛ at a resin temperature of 230°C using a Trouton tester and at a discharge rate of 1 kg/hour over a filtration area of 81 π square millimeters for 5 hours. Using the amount of pressure increase (Δ㎫) as the standard (△), they were classified as ◎, ○, △, and ×, respectively.

◎: The amount of pressure increase is 85% or less of Comparative Example 1.

○: The amount of pressure increase is 90% or less of Comparative Example 1.

△: The amount of pressure increase is equivalent to Comparative Example 1.

×: The amount of pressure increase is higher than that of Comparative Example 1.

(9) Lip contamination (film forming processability)

When the resin composition used for the sealing layer was extruded at 230°C using an extruder and a strand die for 5 hours, contamination of the lips was observed visually, and this was used as a standard (△), and marked as ◎, ○, △, and × below. Classified.

◎: Almost no lip contamination can be confirmed.

○: Some lip contamination is seen.

△: Lip contamination can be clearly confirmed.

×: Lip stains grew and stripe-shaped depressions formed in the strand.

(10) Maximum projection height

The three-dimensional surface roughness SRa is measured using a contact surface roughness (model ET4000A manufactured by Kosaka Laboratories) at a random location of 1 mm x 0.2 mm on the measurement surface from a piece of film measuring 3 cm x 3 cm in all directions, and the maximum The mountain height Rz was obtained. Rz measured using the above method was measured at n = 3, and the average value was obtained.

(11) Number of protrusions larger than 15 ㎛ (piece/0.2 ㎟)

The number of protrusions 15 ㎛ or more is determined by using a contact surface roughness tester (model ET4000A, manufactured by Kosaka Laboratories), and the surface roughness of the sealing layer at a location with a measurement surface of 1 mm × 0.2 mm is randomly determined from a piece of film measuring 3 cm × 3 cm in all directions. The maximum peak height Rz was obtained by measuring and marking protrusions of 15 ㎛ or more. The number of protrusions corresponding to Rz of 15 ㎛ or more was counted and obtained from the average of n = 3 measured values.

(12) Heat sealing start temperature (℃)

Dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Moton was applied to the corona surface of a nylon film (biaxially stretched nylon film manufactured by Toyobo: N1100, 15 ㎛) at a solid content of 3 g/m2 and placed in an oven at 80°C. After volatilizing the solvent, the corona surface of the polyethylene resin film and the adhesive surface were nipped on a temperature control roll at 60°C and laminated. The laminated multilayer film was aged at 40°C for 2 days. Heat sealing was performed on the produced laminated sample with a width of 10 mm at a pitch of 10°C at a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, and a sealing temperature of 90 to 160°C.

The heat-sealed sample was cut into a rectangular shape with a heat-sealing width of 15 mm, set on an autograph (model manufactured by Shimadzu Corporation: UA-3122), and the maximum value of the strength was measured by peeling off the sealing surface at a speed of 200 mm/min. It was measured with n number of 3, and the heat sealing strength and heat sealing temperature at each temperature were plotted. The heat sealing temperature of 4.9 N/15 mm was read from the graph connecting each plot with a straight line, and was used as the heat sealing start temperature.

(13) Achieved heat sealing strength (N/15 ㎜)

Dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Moton was applied to the corona surface of a nylon film (biaxially stretched nylon film manufactured by Toyobo: N1100, 15 ㎛) at a solid content of 3 g/m2 and placed in an oven at 80°C. After volatilizing the solvent, the corona surface of the polyethylene resin film and the adhesive surface were nipped on a temperature control roll at 60°C and laminated. The laminated multilayer film was aged at 40°C for 2 days. The fabricated laminated sample was heat sealed with a width of 10 mm at a pitch of 10°C at a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, and a sealing temperature of 120 to 190°C.

The heat-sealed sample was cut into a rectangular shape with a heat-sealing width of 15 mm, set on an autograph (model manufactured by Shimadzu Corporation: UA-3122), and the maximum value of the strength was measured by peeling off the sealing surface at a speed of 200 mm/min. It was measured with n number of 3, and the heat sealing strength with the highest average value was taken as the achieved sealing strength.

(14) Blocking strength

A laminated film with a nylon film (biaxially stretched nylon film: N1100, 15 μm manufactured by Toyobo) was produced as follows.

To the corona surface of the nylon film, dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Moton is applied to a solid content of 3 g/m2, the solvent is volatilized and removed in an oven at 80°C, and then the corona surface of the polyethylene resin film is applied to the corona surface of the nylon film. The adhesive coated surface was laminated by nipping on a temperature controlled roll at 60°C. The laminated multilayer film was aged at 40°C for 2 days.

The sample (10 cm Place the ends of an aluminum plate (2 mm thick) measuring 7 cm x 7 cm in position, and pressurize at a temperature of 50°C, a pressure of 440 kgf/cm2, and a time of 15 minutes.

The sample and bar (diameter: 6 mm, material: aluminum) blocked by this pressure treatment are mounted on an Autograph (model: UA-3122 manufactured by Shimadzu Corporation), and the bar peels off the blocking portion at a speed (100 m/min). The force was measured.

In this case, the premise is that the bar and peeling surface are horizontal. Four measurements were made on the same sample and expressed as an average value.

(15) Static friction coefficient

A laminated film with a nylon film (biaxially stretched nylon film: N1100, 15 μm manufactured by Toyobo) was produced as follows.

To the corona surface of the nylon film, dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Moton is applied to a solid content of 3 g/m2, the solvent is volatilized and removed in an oven at 80°C, and then the corona surface of the polyethylene resin film is applied to the corona surface of the nylon film. The adhesive coated surface was laminated by nipping on a temperature controlled roll at 60°C. The laminated multilayer film was aged at 40°C for 2 days. The coefficient of static friction between the polyethylene resin film surfaces of the produced laminated film was measured in an environment of 23°C and 65%RH in accordance with JIS-K7125.

(16) Hayes

Only the polyethylene-based resin film was measured using a direct-reading haze meter manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with JIS-K7105.

Haze (%) = [Td (diffuse transmittance %) / Tt (total light transmittance %)] × 100

(17) Flicker feeling

Only the polyethylene resin film was observed with the naked eye, and the flicker sensation was classified as ◎, ○, △, and × below.

◎: Almost no bright spots are felt.

○: There are fine bright spots, but they are uniform and do not cause particular concern.

△: There are partially bright spots and a foreign body sensation is felt.

×: There are bright spots on the entire surface, and transparency is impaired.

(18) Lightweight appearance

After replacing the filter with a filtration accuracy of 60 ㎛ for all layers, film formation was started, and only the polyethylene resin film after 7 days was visually observed in A4 size with n = 3 using the film forming method described in the example. The average value converted to the number of foreign substances per 1,000 ㎠ is shown below. It was classified as ◎, ○, △, ×.

◎: Less than 1 gel-like foreign matter of 0.2 mmϕ or more and 1 mm or less/1,000 ㎠

○: 2 gel-like foreign substances of 0.2 ㎜ϕ or more but 1 ㎜ or less／less than 1,000 ㎠

△: 2 or more gel-like foreign substances measuring 0.2 mmϕ or more but 1 mm or less, less than 4/1,000 ㎠

×: 4 gel-like foreign substances of 0.2 mmϕ or more and 1 mm or less/1,000 ㎠ or more

(19) Scratch resistance

A laminated film with a nylon film (biaxially stretched nylon film: N1100, 15 μm manufactured by Toyobo) was produced as follows.

To the corona surface of the nylon film, dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Moton is applied to a solid content of 3 g/m2, the solvent is volatilized and removed in an oven at 80°C, and then the corona surface of the polyethylene resin film is applied to the corona surface of the nylon film. The adhesive coated surface was laminated by nipping on a temperature controlled roll at 60°C. The laminated multilayer film was aged at 40°C for 2 days. The polyethylene-based resin film surfaces of the produced laminated film were picked up with fingers and rubbed 10 times so that they overlap each other, and observed with the naked eye, and the ease of occurrence of scratches was classified as ◎, ○, △, and × below.

◎: Almost no scratches occur.

○: Fine stripe-shaped scratches occur, but no whitening occurs.

△: Concentration of fine stripes and partial whitening are visible.

×: The rubbed area is almost whitened.

Next, the present invention will be described in more detail through Examples and Comparative Examples, but the present invention is not limited to the examples below.

In the examples and comparative examples, the following raw materials were used.

(polyethylene resin)

(1) 0540F (metallocene-based linear low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 904 kg/m3, MFR 4.0, melting point 111°C)

(2) FV402 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 913 kg/m3, MFR 3.8 g/10 min, melting point 115°C)

(3) FV405 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 923 kg/m3, MFR 3.8 g/10 min, melting point 118°C)

(4) FV407 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 930 kg/m3, MFR 3.2 g/10 min, melting point 124°C)

(5) 3540F (metallocene-based linear low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 931 kg/m3, MFR 4.0 g/10 min, melting point 123°C)

(6) 4540F (metallocene-based linear low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 944 kg/m3, MFR 4.0 g/10 min, melting point 128°C)

(7) Lubmer LS3000 (high molecular weight polyethylene, manufactured by Mitsui Chemicals Co., Ltd., density 969 kg/㎥, MFR 14 g/10 min, heat distortion temperature (4.6 kg/㎠) 80°C)

(Particles made of polyethylene resin)

(1) Mipelon Weight ratio of particle size 55%)

(2) Mipelon PM220 improved product (ultra-high molecular weight polyethylene particles, manufactured by Mitsui Chemicals Co., Ltd., density 940 kg/㎥, melting point 135°C, viscosity average molecular weight 1.8 million, Shore hardness 65D, volume average particle diameter 10 ㎛, exceeding 25 ㎛ Weight ratio of particle size less than 1%)

(inorganic particles)

(1) KMP-130-10 (spherical silica particles, manufactured by Shin-Etsu Silicone Co., average particle diameter 10 ㎛)

(2) Dicalite WF (diatomaceous earth, manufactured by Grefco. Inc., processed to an average particle size of 5 ㎛ using a pin mill grinder)

(organic lubricant)

(1) Ethylenebisoleic acid amide (Ethylenebisoleic acid amide 2% masterbatch EMB11 manufactured by Sumitomo Chemical was used)

(2) Erucic acid amide (Erucic acid amide 4% masterbatch EMB10 manufactured by Sumitomo Chemical was used)

(Examples 1 to 6)

The resin and additives shown in Table 1 were used as raw materials for the sealing layer, laminate layer, and intermediate layer, melted at 240°C using three extruders each, and filtered through a sintered filter with a filtration accuracy of 60 μm, and then T It is co-extruded from a die into a sheet shape, melt-extruded so that the thickness ratio of the sealing layer, middle layer, and laminate layer is 1:3:1, cooled and solidified with a cooling roll at 30°C, and then corona discharge is applied to the laminate layer surface of the obtained sheet. After the treatment, it was wound into a roll at a speed of 150 m/min to obtain a polyethylene-based resin film with a thickness of 50 μm and a wet tension of 45 N/m on the surface of the laminate layer.

The polyethylene-based resin films obtained in Examples 1 to 5 have excellent heat sealing properties, and the blocking resistance and friction coefficient have small fluctuations in measured values between measurement samples, so they have stable blocking resistance and slipperiness, and also have excellent appearance and scratch resistance. The castle was also excellent. Additionally, film forming processability was excellent.

Although the blocking resistance and friction coefficient of the polyethylene-based resin film obtained in Example 6 varied between measurement samples, it was suitable for heavy clothing, etc. and was also excellent in appearance and scratch resistance. Additionally, film forming processability was excellent.

(Comparative Examples 1 to 5)

The resin and additives shown in Table 2 were used as raw materials for the sealing layer, laminate layer, and intermediate layer, melted at 240°C using three extruders each, and filtered through a sintered filter with a filtration accuracy of 60 μm, and then T It is co-extruded from a die into a sheet shape, melt-extruded so that the thickness ratio of the sealing layer, middle layer, and laminate layer is 1:3:1, cooled and solidified with a cooling roll at 30°C, and then corona discharge is applied to the laminate layer surface of the obtained sheet. After the treatment, it was wound into a roll at a speed of 150 m/min to obtain a polyethylene-based resin film with a thickness of 50 μm and a wet tension of 45 N/m on the surface of the laminate layer.

The film obtained in Comparative Example 1 had excellent blocking resistance and slipperiness, but had a slight flicker feeling, poor scratch resistance, and significant filter pressure increase, resulting in poor film forming processability.

The film obtained in Comparative Example 2 had excellent blocking resistance and slipperiness, but had a flicker feeling and poor appearance.

The film obtained in Comparative Example 3 had excellent blocking resistance and transparency, but had a severe flicker feeling and had a significantly poor appearance.

The film obtained in Comparative Example 4 had melting unevenness on the surface, a feeling of flickering, and a significantly poor appearance. Additionally, the blocking resistance, slipperiness, and scratch resistance were poor.

The film obtained in Comparative Example 5 had excellent blocking resistance, but had a flicker feeling and poor appearance. In addition, scratch resistance and film forming processability were poor.

(Comparative Examples 6, 7)

The resins and additives shown in Table 2 were used as raw materials for the sealing layer, laminate layer, and intermediate layer, each was melted at 240°C using three extruders, and filtered through sintered filters with filtration precision of 200 μm and 120 μm. Afterwards, it is co-extruded from a T die into a sheet shape, melt-extruded so that the thickness ratio of the sealing layer, middle layer, and laminate layer is 1:3:1, and cooled and solidified with a cooling roll at 30°C, and then the laminate layer surface of the obtained sheet is After corona discharge treatment, it was wound into a roll at a speed of 150 m/min to obtain a polyethylene-based resin film with a thickness of 50 μm and a wet tension of 45 N/m on the surface of the laminate layer.

The polyethylene-based resin films obtained in Comparative Examples 6 and 7 had excellent heat sealing properties, and had stable blocking resistance and slipperiness, with small fluctuations in blocking resistance and friction coefficient between measurement samples. In addition, it was excellent in scratch resistance and film forming processability. However, the presence of gel-like material in appearance increased over time, making it inferior to Examples 1 to 6.

The results are shown in Tables 1 and 2.

Above, the method for producing the polyethylene resin film of the present invention has been described based on a plurality of examples, but the present invention is not limited to the configuration described in the above examples, and the configuration described in each example can be appropriately combined. etc., the composition can be changed appropriately within the range without deviating from the purpose.

The method for producing a polyethylene-based resin film described in the present invention can efficiently and stably produce a polyethylene-based resin film with excellent properties, so it can be suitably used for films for a wide range of purposes, such as for food packaging.

Claims (3)

Particles made of a polyethylene resin having a viscosity average molecular weight of 1.5 million to 2.5 million, a volume average particle diameter of the particles of 2 ㎛ to 20 ㎛, and a proportion of particles with a particle diameter of 25 ㎛ or more of less than 1% by weight, and ethylene A process of melt-kneading a polyethylene resin composition containing a polyethylene-based resin that is a homopolymer of monomers, a copolymer of ethylene monomer and α-olefin, or a mixture thereof, with a density of 900 to 940 kg/m3 and a melting point of 85°C or higher. , a process of melt-extruding the polyethylene resin composition to form a molten polyethylene resin composition sheet, and a process of cooling and solidifying the molten polyethylene resin composition sheet, and in the process of melt-kneading the polyethylene resin composition, a filter with a filtration accuracy of 100 ㎛ or less is used. A method of producing a polyethylene-based resin film including the process of using and filtering. According to paragraph 1,
A method for producing a polyethylene resin film in which the particles made of the polyethylene resin have a viscosity average molecular weight of 1.5 million or more and a melting point peak temperature by DSC of 150°C or less. According to claim 1 or 2,
A method of producing a polyethylene-based resin film wherein the filter has a filtration precision of 80 ㎛ or less.