JPWO2019093216A1 - Manufacturing method of polyethylene resin film - Google Patents

Abstract

Efficiently and stably manufacture a polyethylene-based resin film that has excellent heat-sealing properties and also has excellent appearance and scratch resistance. A step of melt-kneading a polyethylene resin composition containing polyethylene-based resin particles and a polyethylene-based resin, a step of melt-extruding the polyethylene resin composition to obtain a molten polyethylene resin composition sheet, and cooling the molten polyethylene resin composition sheet. A method for producing a polyethylene-based resin film, which comprises a step of solidifying and filtering the polyethylene resin composition using a filter having a filtration accuracy of 100 μm or less in the step of melt-kneading.

Description

The present invention relates to a method for producing a polyethylene-based resin film. More specifically, the present invention relates to a method for producing a polyethylene-based resin film, which is excellent in stable blocking resistance or stable slipperiness, and is also excellent in appearance and scratch resistance.

In recent years, packaging or containers using films have been used in a wide range of fields due to convenience, resource saving, reduction of environmental load, and the like. Compared to conventional molded containers and molded products, films have the advantages of being lightweight, easy to dispose of, and low cost.

For example, the sealant film is generally used by laminating with a base film such as a biaxially stretched nylon film, a biaxially stretched ester film, and a biaxially stretched polypropylene film, which are inferior in low temperature thermal adhesion to the sealant film. Is. If these base films are stored in a roll after laminating, blocking may occur between the sealant film and the base film, making it difficult to rewind the laminated film before bag making, or bag making. Blocking occurred between the sealant films on the inner surface of the bag being processed, which sometimes made it difficult to fill the food.
Therefore, a method is known in which powder such as starch is sprinkled on the surface of the sealant film to avoid blocking between the sealant film and the base material and blocking between the sealant films as described above.
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 adhering to the sealant film is directly mixed with the food in the package, and the heat seal strength is lowered. Was occurring.

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

However, with this measure, scratches are likely to occur when the film surfaces containing inorganic fine powder or inorganic particles such as alumina and silica added to the polyethylene-based film are rubbed against each other, and a laminating machine or a bag making machine is used as a sealant. There is also a problem that the inorganic fine powder or the inorganic particles easily fall off when the filler or the laminate with the base film passes through and comes into contact with a part of the machine (see, for example, Patent Document 1).

Further, a polyethylene resin film using organic crosslinked particles composed of a copolymer containing an acrylic monomer and a styrene monomer as main components has been reported. (See, for example, Patent Document 1.).
However, this measure is not as vulnerable as inorganic particles, but not sufficient. In addition, the problems of blocking resistance and particle dropout still remained.

Furthermore, when the polyethylene raw material resin composition is melt-kneaded and extruded into a sheet, the polyethylene resin is decomposed and recombined to form a crosslinked organic substance, so-called gel, which is filtered using a filter for quality control. Is essential. At that time, the inorganic particles and the crosslinked organic particles aggregate, and if the filter is clogged, the filter must be replaced, which causes problems such as a decrease in operability and an increase in cost. Further, if the extrusion speed is prioritized and a filter having low filtration accuracy is used, so-called gel removal is not sufficient, and there is a problem that gel defects increase and quality deteriorates with time.

Japanese Unexamined Patent Publication No. 10-86300

An object of the present invention is to efficiently and stably produce a polyethylene-based resin film having excellent heat-sealing properties, appearance, and scratch resistance, and having less particles falling off.

As a result of diligent studies in view of the actual situation, the present inventors have found that the above problems can be solved by producing a polyethylene-based resin film using particles made of polyethylene-based resin and using a filter having high filtration accuracy. The invention has been solved.

That is, the present invention relates to a step of melt-kneading a particle made of a polyethylene-based resin and a polyethylene resin composition containing the polyethylene-based resin, a step of melt-extruding the polyethylene resin composition to obtain a molten polyethylene resin composition sheet, and a molten polyethylene resin. This is a method for producing a polyethylene resin film, which includes a step of cooling and solidifying the composition sheet, and a step of filtering using a film having a filtration accuracy of 100 μm or less in a step of melt-kneading the polyethylene resin composition.

In this case, it is preferable that the polyethylene-based particles 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.

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

INDUSTRIAL APPLICABILITY According to the present invention, a polyethylene-based resin film having excellent heat-sealing properties and excellent appearance and scratch resistance can be efficiently and stably produced.

(Particles made of polyethylene resin)
The particles made of the polyethylene-based 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 further preferably 1.7 million or more. Further, it is preferably 2.5 million or less, more preferably 2.4 million or less, and further preferably 2.3 million or less.
With a viscosity average molecular weight in this range, the maximum peak height of the surface layer on at least one side 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 are not mixed, and they are melt-mixed and extruded. Since it is easy to maintain the shape of the particles made of polyethylene resin even in the film, and aggregation due to fusion or adhesion between the particles is unlikely to occur, the particle size of the particles is commensurate with that of the inorganic particles on the film surface. It is estimated that protrusions can be formed.
When the viscosity average molecular weight of the particles made of polyethylene resin is less than 1.5 million, when the temperature at the time of melt mixing is higher than the melting point peak, it is decomposed or fused by heat or shear, or due to partial compatibility with the base resin. Since the shape of the grain warp changes, it becomes impossible to form protrusions like conventional inorganic particles and organic crosslinked polymer beads, and not only the function as an anti-blocking agent becomes insufficient, but also the appearance such as transparency and the appearance of the film Affects mechanical strength or heat sealability.
Further, when the viscosity average molecular weight exceeds 2.5 million, it becomes easy to maintain the particle shape when melt-mixing and forming an extruded film, but in that case, it tends to be difficult to form suitable film surface protrusions. ..
Furthermore, surprisingly, although particles made of polyethylene-based resin having a viscosity average molecular weight of 1.5 million or more have the property of being difficult to aggregate, they are inorganic from other polyethylene-based resins mixed with the particles. It was found that it has the characteristic of being harder to fall off than particles.
Further, when the viscosity average molecular weight of the particles made of polyethylene resin is 1.5 million or more, the particles themselves have lubricity and contribute to improvement of blocking resistance and slipperiness, and since the particles made of polyethylene resin are soft, they are scratch resistant. It is thought that the sex will also improve.

The average particle size of the polyethylene-based resin particles used in the present invention is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more. The average particle size is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.
In addition, it preferably does not contain particles having a particle size of 25 μm or more. Even if the average particle size is 20 μm or less, if 1% or more of the particles have a particle size of 25 μm or more, the maximum peak height of the film surface tends to exceed 15 μm. Then, when the film surface is visually inspected, flicker described later occurs. ..
Further, particles having a size of 25 μm or more are not preferable in that they have a drawback and the quality is deteriorated.

(Polyethylene resin)
In the present invention, the polyethylene-based resin other than the "particles made of the polyethylene-based resin" is a homopolymer of an ethylene monomer, a copolymer of an ethylene monomer and an α-olefin, and a mixture thereof. -Olefins include propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, decene-1, and the like.

The density range of the polyethylene resin other than the particles made of the polyethylene resin in the present invention is not particularly limited, but in order to obtain a polyethylene resin film having both heat sealability and blocking resistance, 900 to 940 kg / m. ³ is preferable, 905 to 935 kg / m ³ is more preferable, 910 to 930 kg / m ³ is further preferable, and 915 to 925 kg / m ³ is particularly preferable. Polyethylene resins having a density of less than 900 kg / m ³ tend to have reduced blocking resistance.
A polyethylene resin having a density of more than 940 kg / m ³ has a high heat sealing start temperature, is difficult to make a bag, and is inferior in transparency, but when a polyethylene resin having a density of more than 940 kg / m ³ is used. The present invention is very effective for producing a polyethylene-based resin film having excellent strength for packaging heavy objects and the like by reducing the frequency of filter replacement, and for producing a film having few defects.
For blocking resistance, a sample in which the measurement surfaces of the film are overlapped is subjected to a heat press (Tester Sangyo Co., Ltd. model: SA-303) in a size of 7 cm x 7 cm, a temperature of 50 ° C., a pressure of 440 kgf / cm ² , and a time of 15 minutes. Pressurize. The sample and bar (diameter 6 mm, material: aluminum) blocked by this pressure treatment were attached to the autograph (Shimadzu model: UA-3122) so that the bar and the peeling surface were horizontal, and the bar was speeded (100 m). The force at which the blocking part is peeled off is measured four times at (/ min), and the average value is used as an index. When a polyethylene resin with a density greater than 0.940 g / m ³ is used. Not only was it liable to fluctuate in each of the four measurements, but it was also observed that the heat seal start temperature tended to increase. It is preferable that the fluctuation of the measured value of each of the four measurements is at the same level as when the inorganic particles are used.
The reason why the measured value tends to fluctuate for each measurement sample is not clear at present, but when a high-density polyethylene resin is used as a base, the viscosity average molecular weight of the polyethylene resin particles decreases and the particles other than the polyethylene resin particles are used. It is presumed that this is because the particle size changes due to the entanglement of the molecular chains with the polyethylene-based resin, and the resulting surface protrusions become more non-uniform.

As the polyethylene-based resin other than the particles made of the polyethylene-based resin of the present invention, the melt flow rate (hereinafter, may be referred to as MFR) is preferably about 2.5 to 10 g / min from the viewpoint of film forming property and the like. .. Here, the MFR was measured according to JIS K7210. Further, the polyethylene-based resin is synthesized by a method known per se.

When a low resin having an MFR of 2.5 g / 10 minutes or less of the polyethylene-based resin other than the particles made of the polyethylene-based resin in the present invention is used, the particles made of the polyethylene-based resin are similar to the description in the density. Care must be taken in the extrusion conditions because the particle size is likely to change due to a decrease in the average molecular weight of the viscosity or entanglement of the molecular chains with the polyethylene resin other than the particles made of the polyethylene resin. When high-speed film formation is performed with a large film-forming machine, an MFR of about 3 to 4 g / 10 minutes is particularly preferable for film-forming property.

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

In the present invention, the polyethylene-based resin other than the particles made of the polyethylene-based resin may be a single system, but two or more kinds of polyethylene-based resins having different densities in the above density range may be blended. When two or more types of polyethylene resins having different densities are blended, the average density and blending ratio can be estimated by GPC measurement or density measurement.

The polyethylene-based resin other than the particle density as described above is made of polyethylene resin 900~940kg / m ^3, a transparent, flexible and tear strength, high pressure process is excellent in average tensile strength, low density polyethylene (LDPE), linear short-chain branched polyethylene (LLDPE), which is obtained by copolymerizing a small amount of butene-1, hexene-1 octene-1, having many short molecular chains in the molecular chain, and having excellent sealing performance and physical strength. Select a metallocene-catalyzed linear short-chain branched polyethylene (LLDPE) that shows a very sharp molecular weight distribution, a uniform distribution of copolymers, and excellent tearing, tensile, piercing strength, and pinhole resistance, depending on the application. be able to.

The amount of the particles made of the polyethylene resin added in the present invention is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and further preferably 0.4% by weight or more with respect to the entire film. preferable. Further, 2% by weight or less is preferable, 1.5% by weight or less is more preferable, and 1.0% by weight or less is further preferable. When the amount of particles made of polyethylene resin added is less than 0.1% by weight, it is difficult to set the maximum mountain height of the surface layer on at least one side of the obtained film to 2 μm or more per specified area (0.2 mm ² ). Therefore, it becomes difficult to obtain anti-blocking property and slipperiness. Further, when the addition amount of the particles made of polyethylene resin is more than 2% by weight, the number of protrusions on the surface increases, the transparency is poor, and the low temperature sealing property is apt to be poor.

In the polyethylene-based resin film of the present invention, known additives such as antioxidants, neutralizers, organic lubricants, drip-free agents, and antistatic agents are used in combination as long as the object and effect of the present invention are not impaired. Is also good. The blending of these additives can be appropriately blended when each component of the polyethylene-based resin composition is blended and mixed.

It is preferable to add an organic lubricant to the polyethylene-based resin film in the present invention. The slipperiness and blocking prevention effect of the laminated film are improved, and the handleability of the film is improved. It is considered that the reason is that the organic lubricant bleeds out and exists on the film surface, so that the lubricant effect and the mold release effect are exhibited. Further, it is preferable to add an organic lubricant having a melting point of room temperature or higher. Examples of the organic lubricant include fatty acid amides and fatty acid esters. Specific examples thereof include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and ethylene bisoleic acid amide. These may be used alone, but it is preferable to use two or more of them in combination because the slipperiness and the blocking prevention effect can be maintained even in a harsh environment.

The lower limit of the organic lubricant amide concentration in the film or the layer containing particles made of the polyethylene resin of the present invention 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 2500 ppm, more preferably 2000 ppm. If it exceeds the above, it slips too much, which is not preferable.
Further, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer and the like may also be mixed and used as long as the object and effect of the present invention are not impaired.

The polyethylene-based resin film of the present invention needs to be substantially free of inorganic particles. When inorganic particles are substantially contained, not only is it difficult to obtain the effects of adding particles made of polyethylene resin such as scratch resistance and particles do not fall off, but also when a filter with high filtration accuracy is used, the filter boost is increased. The operability deteriorates quickly due to filter replacement. The inorganic particles referred to here are inorganic substances generally used as anti-blocking agents such as silica, talc, calcium carbonate, diatomaceous earth, and zeolite, and substantially not contained is inorganic in the entire polyethylene-based resin film of the present invention. It means that the ratio of the amount of particles is 0.2% by weight or less. More preferably, it is 0.1% by weight or less.

The polyethylene-based resin film of the present invention needs to be substantially free of crosslinked organic particles. When the crosslinked organic particles are substantially contained, it becomes difficult to obtain the effects of adding the particles made of polyethylene resin, such as scratch resistance and the particles not falling off. The crosslinked organic particles referred to here are crosslinked particles typified by a polymethyl acrylate resin or the like, and substantially not contained means that the ratio of the amount of the crosslinked organic particles in the entire polyethylene-based resin film of the present invention is 0.2 weight by weight. It means that it is less than%. More preferably, it is 0.1% by weight or less.

(Film formation method)
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 a polyethylene-based resin and a polyethylene-based resin other than particles made of a polyethylene-based resin, and melt-kneading. It is preferable to employ a step of melt-extruding the resin composition to obtain a molten resin composition sheet and a step of cooling and solidifying the molten resin composition sheet.
The polyethylene-based resin film in the present invention may be a single layer or may be laminated. In the case of lamination, another layer different from the layer containing particles made of polyethylene-based resin and having a maximum mountain 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, further preferably 15 μm or more, and particularly preferably 20 μm or more. Further, 200 μm or less is preferable, 150 μm or less is more preferable, and 100 μm or less is particularly preferable. If it is less than 3 μm, the effect of the particles made of the polyethylene resin is reduced, and the effect of blocking resistance and slipperiness is hard to be obtained.
In the case of lamination, the thickness of the layer containing particles made of polyethylene resin and having a maximum peak height of at least one surface layer of 2 μm or more and 15 μm or less is preferably 3 μm or more, more preferably 10 μm or more. , 15 μm or more is more preferable, and 20 μm or more is particularly preferable. Further, 200 μm or less is preferable, 150 μm or less is more preferable, and 100 μm or less is particularly preferable. If it is less than 3 μm, the effect of the particles made of the polyethylene resin is reduced, and the effect of blocking resistance and slipperiness is hard to be obtained.

(Raw material mixing process)
When mixing the particles made of polyethylene-based resin and the polyethylene-based resin other than the particles made of polyethylene-based resin, any method may be used as long as these are uniformly mixed, and when using a masterbatch, a ribbon blender, Examples thereof include a method of mixing using a henschel mixer, a tumbler mixer and the like. If it is directly attached, particles made of polyethylene resin may be attached to the resin to which the adhering agent is attached, or may be added directly to the extruder by a side feed or the like.
A method of mixing a small amount of a master batch made of a high concentration of polyethylene resin particles with a polyethylene resin other than the polyethylene resin particles with a polyethylene resin other than the polyethylene resin particles is used. Dispersibility is also good and simple. However, particles made of polyethylene resin are directly mixed with linear low-density polyethien, homopolymer of ethylene monomer, and copolymer of ethylene monomer and α-olefin without using a master batch. In this case, since high dispersibility can be obtained, direct attachment by a side feed method or the like is preferable in terms of cost.

(Melting and kneading process)
First, as the film raw material, the particles made of the polyethylene resin and the polyethylene resin other than the particles made of the polyethylene resin are dried or dried with hot air so that the water content of the polyethylene resin is less than 1000 ppm. Next, each raw material is weighed, mixed, supplied to an extruder, and melt-kneaded.

The lower limit of the melt mixing temperature of the polyethylene-based resin composition obtained by mixing is preferably 200 ° C., more preferably 210 ° C., and even more preferably 220 ° C. If it is less than the above, the discharge may become unstable. The upper limit of the melting temperature of the resin composition is preferably 260 ° C. If it exceeds the above, the decomposition of the resin composition proceeds, and the amount of foreign substances such as crosslinked organic substances, so-called gels, produced as a result of recombination increases.
When the above-mentioned antioxidant is contained in the polyethylene-based resin composition, melt extrusion at a higher temperature is 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, even though the temperature is much lower than the temperature at the time of melt-kneading when mixed with a polyethylene-based resin other than the polyethylene-based resin particles. Surprisingly, the polyethylene-based resin film obtained by being extruded from the T-die without being dispersed in the polyethylene-based resin other than "particles made of polyethylene-based resin" at the molecular level and undergoing a cooling step is a polyethylene-based resin. The particles made of the material exist in the polyethylene-based resin other than the particles made of the polyethylene-based resin while maintaining the grain diameter and shape before addition.

(filtration)
In the melt-kneading step, high-precision filtration can be performed in order 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 sintered filter medium, in addition to foreign substances such as so-called gel, Si, Ti, Sb, and Ge derived from additives such as catalysts. , Cu is excellent in removing aggregates containing Cu as a main component and is suitable. 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 the polyethylene resin in the present invention are melted during melt kneading, not only can they be filtered with a high-precision filter medium, but also there are few coarse particles, so there is an advantage that the pressure increase due to clogging is smaller than that of inorganic particles. is there. Furthermore, by reducing the average particle size of the particles made of polyethylene resin or narrowing the particle size distribution, clogging is less likely to occur even if industrially produced with a high-precision filter medium having a filtration accuracy of 60 μm or less, and foreign matter can be removed. Moreover, there is an advantage that the blockin resistance obtained by the particles made of polyethylene-based resin is not impaired.
The filtration accuracy referred to here is the nominal filtration accuracy, and has the ability to capture 60% or more of particles having a size larger than the indicated filtration accuracy (for example, particles having a filtration accuracy of 60 μm or more). The absolute filtration accuracy is a performance that captures 99.9% or more of particles having a size larger than the indicated filtration accuracy, but even if the nominal filtration accuracy is, it is preferable that the performance is close to the absolute filtration accuracy.

(Filter boost)
It is preferable that the amount of pressure applied during the melt-kneading of the polyethylene-based resin composition is small. The method for measuring the amount of pressurization was the method described in the examples.

(Melting extrusion process)
Next, the molten polyethylene-based resin composition sheet is melt-extruded from, for example, a T-shaped die, cast on a cooling roll, and cooled and solidified to obtain an unstretched sheet. As a specific method for this, it is preferable to cast it on a cooling roll.
Since the particles made of polyethylene-based resin used in the present invention are originally hydrophobic resins, the hydrophobicity of the surface of the particles does not change even after undergoing melt-kneading and extrusion steps, and can be seen in inorganic particles whose surface has been hydrophobized. It is extremely unlikely that heat-deteriorated substances, so-called eye particles, will accumulate on the lips of T-shaped dies.
Examples include a method of melt-extruding a molten polyethylene resin composition sheet to form a film by a T-die method or an inflation method, but the T-die method is particularly effective in that the melting temperature of the resin composition can be raised. desirable.

(Lip dirt)
When the polyethylene-based resin composition is melt-extruded from the T-type die, it is preferable that the lip mouth of the T-type die is less contaminated. The lip stain was measured by the method described in Examples.

(Cooling and solidification process)
For example, it is preferable to cast a molten sheet of a polyethylene-based resin composition melt-extruded from a T-shaped die onto a cooling roll for cooling. The lower limit of the cooling roll temperature is preferably 10 ° C. If it is less than the above, not only the effect of suppressing crystallization may be saturated, but also problems such as dew condensation may occur, which is not preferable. The upper limit of the cooling roll temperature is preferably 70 ° C. or lower. If it exceeds the above, the crystallinity may become too high and the appearance may deteriorate. When the temperature of the cooling roll is within the above range, it is preferable to lower the humidity of the environment near the cooling roll in order to prevent dew condensation.
In casting, the temperature of the surface of the cooling roll rises because the high-temperature resin comes into contact with the surface. Normally, the cooling roll is cooled by flowing cooling water through the piping inside, but the cooling roll is cooled by ensuring a sufficient amount of cooling water, devising the arrangement of the piping, and performing maintenance to prevent sludge from adhering to the piping. It is necessary to reduce the temperature difference in the width direction of the surface. At this time, the thickness of the unstretched sheet is preferably in the range of 3 to 200 μm.

(Multi-layer configuration)
The polyethylene-based resin film in the present invention may have a multilayer structure. In the case of a multilayer, in addition to a layer containing particles made of the polyethylene resin described above and having a maximum mountain height of at least one surface layer of 2 μm or more and 15 μm or less, one layer or two or more layers are provided. be able to.
As a specific method for forming multiple layers in this way, a general multi-layer device (multi-layer feed block, static mixer, multi-layer multi-manifold, etc.) can be used.
For example, a method of laminating thermoplastic resins fed from different flow paths using two or more extruders in multiple layers using a feed block, a static mixer, a multi-manifold die, or the like can be used. It is also possible to introduce the above-mentioned multi-layer device into the melt line from the extruder to the T-type die by using only one extruder.

In the case of a three-layer structure, a layer containing particles made of polyethylene resin and having a maximum mountain height of at least one surface layer of 3 μm or more and 15 μm or less is used as a seal layer (A layer), and the other layers are intermediate layers. (B layer) and laminated layer (C layer) are used, and it is preferable to include them in this order.
The outermost layers are A layer and C layer, respectively.

Examples of the polyethylene-based resin used in the intermediate layer (B layer) and the laminated layer (C layer) include one or a mixture of two or more selected from ethylene / α-olefin copolymer and high-pressure polyethylene. .. The above-mentioned ethylene / α-olefin copolymer is a copolymer of ethylene and an α-olefin having 4 to 18 carbon atoms, and examples of the α-olefin include butene-1, hexene-1, 4-methylpentene-1, and the like. Examples thereof include octene-1 and desen-1.
The film obtained from these polyethylene-based resins has excellent heat-sealing strength, hot-tacking property, contaminant sealing property, and impact resistance, and the polyethylene-based resin has other properties as long as it does not impair these properties. A resin, for example, an ethylene / vinyl acetate copolymer, an ethylene / acrylic ester copolymer, or the like may be mixed and used.

At this time, the polyethylene-based resins used for the intermediate layer (B layer) and the laminate layer (C layer) may be the same or different. Further, particles made of polyethylene resin may or may not be added. However, it does not substantially contain inorganic particles and organic crosslinked particles. Substantially not contained means that the ratio of the amount of crosslinked organic particles in the entire polyethylene-based 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-based resin in each layer of the film is the sealant layer (A layer) ≤ intermediate layer (B layer) ≤ laminate layer (C layer). Since the blended organic lubricant does not easily move to a dense layer, it is effective in maintaining the slipperiness after laminating.

At this time, the lower limit of the densities of the intermediate layer (B layer)) and the laminated layer (C layer) is preferably 900 kg / m ³ , more preferably 920 kg / m ³ , and further preferably 930 kg / m ³ . is there. If it is less than the above, the waist is weak and it may be difficult to process.
The upper limit of the densities of the intermediate layer (B layer)) and the laminated layer (C layer) is preferably 960 kg / m ³ , more preferably 940 kg / m ³ , and further preferably 935 kg / m ³ .

The above-mentioned organic lubricant may be used for the intermediate layer (B layer) of the polyethylene-based 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 intermediate layer (B layer) is preferably 2000 ppm, more preferably 1500 ppm. If it exceeds the above, it may slip too much and cause winding misalignment.

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

In the present invention, it is preferable to perform an active ray treatment such as a corona treatment on the laminated layer (C layer) surface of the polyethylene-based resin film described above. The correspondence improves the laminate strength.

In the case of two layers, a layer containing particles made of polyethylene resin and having a maximum mountain height of at least one surface layer of 3 μm or more and 15 μm or less is used as a seal layer (A layer), and the other layer is a laminate layer (C). Layer) is good.

(Maximum protrusion height)
The maximum mountain height of the surface layer on at least one side of the polyethylene-based resin film of the present invention needs to be 2 μm or more and 15 μm or less. If the maximum mountain height Rz exceeds 15 μm, appearance defects will occur, which is not preferable. The measuring method is the method described in Examples.

(Number of protrusions of 15μ or more)
In the polyethylene-based resin film of the present invention, the maximum mountain height of the surface is preferably 2 μm or more and 15 μm or less, and the number of protrusions (pieces / 0.2 mm ² ) exceeding 15 μm in the surface layer is preferably 0 or less. The smaller the number, the worse the appearance such as flickering and haze. The measuring method is the method described in Examples.

(Heat seal start temperature)
The upper limit of the heat seal start temperature of the polyethylene-based resin film laminated with the biaxially stretched nylon film (15 μm) is preferably 130 ° C., more preferably 120 ° C. If it exceeds the above, it may be difficult to process the seal. The measuring method is the method described in Examples.

(Achieved heat seal strength)
The lower limit of the heat seal strength reached at 120 ° C. of the polyethylene resin film laminated with the biaxially stretched nylon film (15 μm) is preferably 30 N / 15 mm, more preferably 35 N / 15 mm. If it is less than the above, the bag may be easily torn after the bag is made.
The upper limit of the heat seal strength reached at 120 ° C. of the polyethylene resin film laminated with the biaxially stretched nylon film (15 μm) is preferably 70 N / 15 mm, more preferably 65 N / 15 mm. If it exceeds the above, it may be difficult to open the bag after making the bag. The measuring method is the method described in Examples.

(Blocking strength)
The lower limit of the blocking strength of the polyethylene-based resin film laminated with the biaxially stretched nylon film (15 μm) is preferably 0 mN / 20 mm, more preferably 10 mN / 20 mm, and further preferably 15 mN / 20 mm.
The upper limit of the blocking strength is preferably 150 mN / 20 mm, more preferably 50 mN / 20 mm, and even more preferably 40 mN / 20 mm. If it exceeds the above, the slipperiness immediately after unwinding may deteriorate. The measuring method is the method described in Examples.

(Friction strength)
The lower limit of the coefficient of static friction after laminating the polyethylene-based resin film laminated with the 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 too much during winding and cause winding misalignment.
The upper limit of the coefficient of static friction after laminating is preferably 0.50, more preferably 0.4. If it exceeds the above, the opening property after bag making is poor, and the loss during processing may increase. The measuring method is the method described in Examples.

(Haze)
The lower limit of the haze of the polyethylene-based resin film of the present invention is preferably 3%, more preferably 4%, and even more preferably 5%. If it is less than the above, the amount of anti-blocking agent may be small, which may cause blocking.
The upper limit of haze is preferably 15%, more preferably 12%, and even more preferably 10%. If it exceeds the above, it may be difficult to visually recognize the contents. The measuring method is the method described in Examples.

(Flickering feeling)
It is preferable that the polyethylene-based resin film of the present invention hardly feels flicker, or has fine flicker but is uniform and is not particularly noticeable. The measuring method is the method described in Examples.
The so-called non-powder type, which has blocking resistance without sprinkling powder such as starch on the film surface, has conventionally added inorganic particles having an average particle size of about 10 μm, but the flicker feeling may be inferior. is there.

(Scratch resistance)
The polyethylene-based resin film laminated with a biaxially stretched nylon film (15 μm) has almost no scratches or fine streaks even after being pinched with fingers so that the sealing surfaces overlap each other and rubbed 10 times. However, it is preferable that the film does not whiten. The measuring method is the method described in Examples.
The so-called non-powder type, which has blocking resistance without sprinkling powder such as starch on the film surface, has conventionally added inorganic particles having an average particle size of about 10 μm, but the scratch resistance is inferior.

(Young's modulus)
The lower limit of Young's modulus (MD) of the polyethylene-based resin film of the present invention is preferably 100 MPa, more preferably 200 MPa. If it is less than the above, the waist may be too weak and it may be difficult to process. The upper limit of Young's modulus (MD) 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 waist may be too weak and it may be difficult to process.
The upper limit of Young's modulus (TD) is preferably 1000 MPa, more preferably 600 MPa.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not particularly limited by the following Examples. The detailed description of the present invention and the measured values of each item in the examples were measured by the following methods.

Hereinafter, embodiments of the present invention will be described in detail.
(1) Method for measuring particles made of polyethylene-based resin For particles made of polyethylene-based resin, the physical properties of the raw material resin before processing were measured.
Even after film molding, the film can be melted at a temperature at which polyethylene other than polyethylene resin particles can be completely melted using decan as a solvent, and the residue can be filtered with a filter with a filtration accuracy of 2 μm. After the particles are completely melted in the decan, the particles made of polyethylene resin can be separated and measured by a method such as separating a portion having a high molecular weight by GPC or the like.

(2) The viscosity average molecular weight of the particles made of polyethylene resin was measured according to ASTM-D4020.

(3) Average particle size of particles made of polyethylene resin
The average particle size of the polyethylene resin particles before use was measured as follows.
Particles are dispersed in ion-exchanged water stirred at a predetermined rotation speed (about 5000 rpm) using a high-speed stirrer, and the dispersion is added to isoton (physiological saline) and further dispersed by an ultrasonic disperser, and then called. The particle size distribution was obtained by the counter method and calculated as the volume average particle size.

(4) Particle size distribution of particles made of polyethylene resin
The proportion of particles made of polyethylene resin before use having a particle size 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 heating rate of 10 ° C./min. The melting endothermic peak temperature detected here was taken as the melting point.

(6) Density, MFR, and melting point of polyethylene-based resin other than particles made of polyethylene-based resin The raw materials before film molding were measured by the following methods.
The polyethylene resin other than the particles made of the polyethylene resin, which forms the layer containing the particles made of the polyethylene resin, has all layers if it is a single layer, and the layer structure if it is laminated, after confirming the layer structure with an electron microscope or the like. The surface is scraped to a thickness less than the surface layer, and the solvent is removed from the filtered solution obtained in (1) above, and the same measurement can be performed. When scraping from the lamination, it can be relatively easily performed by laminating on a polyethylene terephthalate (PET) film or the like and then scraping off with a razor or the like.

(density)
It was measured by the density gradient tube method according to JIS-K7112.

(Melt flow rate: MFR) (g / 10 minutes)
It was measured at a temperature of 190 ° C. according to JIS-K7210.

(Melting point)
Using a differential scanning calorimeter (DSC) manufactured by SII, the measurement was performed at a sample amount of 10 mg and a heating 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 material resin composition before processing.
Even after the film is formed, the film is melted at a temperature at which polyethylene other than the particles made of polyethylene resin is completely melted using decan as a solvent, and the residue is filtered with a filter having a filtration accuracy of 2 μm. It is also possible to separate and measure inorganic particles with.

(8) Filter boosting (film formation workability)
When the resin composition used for the seal layer is discharged to a Naslon sintered filter with a filtration accuracy of 60 μm at a resin temperature of 230 ° C. using a Trouton tester and discharged to a filtration area of 81π square millimeters at a discharge rate of 1 kg / hour for 5 hours. Based on the boosted amount (ΔMPa), they were classified into the following ⊚, ◯, Δ, and ×, respectively.
⊚: The amount of step-up is 85% or less of Comparative Example 1.
◯: The amount of boosting is 90% or less of Comparative Example 1.
Δ: The amount of boosting is equivalent to that of Comparative Example 1.
X: The amount of boosting is higher than that of Comparative Example 1.

(9) Lip stain (film formation workability)
Visually observe the dirt on the lip when the resin composition used for the seal layer is extruded at 230 ° C using a strand die with an extruder for 5 hours, and based on that as a reference (△), the following ◎, ○, △, × It was classified into.
⊚: Almost no lip stain can be confirmed.
◯: Slight lip stains are seen.
Δ: Lip stains can be clearly confirmed.
X: Lip stains grew and streaky dents were formed on the strands.

(10) Maximum protrusion height Three-dimensional surface roughness SRa uses contact-type surface roughness (manufactured by Kosaka Laboratory, model ET4000A), and is arbitrarily measured from a 3 cm x 3 cm square film piece at a location of 1 mm x 0.2 mm. The surface roughness of the film was measured to determine the maximum mountain height Rz. Rz measured by the above method was measured at n = 3 to obtain an average value.

(11) Number of protrusions of 15 μm or more (pieces / 0.2 mm ² )
For the number of protrusions of 15 μm or more, contact type surface roughness (manufactured by Kosaka Laboratory, model ET4000A) is used, and the surface roughness of the seal layer at the measurement surface of 1 mm × 0.2 mm is arbitrarily determined from a film piece of 3 cm × 3 cm square. It was measured and obtained by marking a protrusion having a maximum mountain height Rz of 15 μm or more. The number of protrusions corresponding to Rz of 15 μm or more was counted and determined from the average of n = 3 measured values.

(12) Heat seal start temperature (° C)
Toyo Morton's dry laminating adhesive (TM569, CAT-10L) was applied to the corona surface of a nylon film (Toyobo biaxially stretched nylon film: N1100, 15 μm) so that the solid content was 3 g / m ^2, and the temperature was 80 ° C. After volatilizing and removing the solvent in the oven, the corona surface of the polyethylene resin film and the adhesive coated surface were niped and laminated on a temperature control roll at 60 ° C. The laminated laminated film was aged at 40 ° C. for 2 days. The prepared laminated sample was heat-sealed with a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, and a sealing temperature of 90 to 160 ° C. at a pitch of 10 ° C. and a width of 10 mm.
The heat-sealed sample is cut into strips so that the heat-sealed width is 15 mm, set on an autograph (Shimadzu Seisakusho model: UA-3122), and the maximum strength of peeling the sealed surface at a speed of 200 mm / min. The value was measured with n number 3 and the heat seal strength and heat seal temperature at each temperature were plotted. The heat seal temperature of 4.9 N / 15 mm was read from the graph connecting each plot with a straight line and used as the heat seal start temperature.

(13) Reached heat seal strength (N / 15 mm)
Toyo Morton's dry laminating adhesive (TM569, CAT-10L) was applied to the corona surface of a nylon film (Toyobo biaxially stretched nylon film: N1100, 15 μm) so that the solid content was 3 g / m ^2, and the temperature was 80 ° C. After volatilizing and removing the solvent in the oven, the corona surface of the polyethylene resin film and the adhesive coated surface were niped and laminated on a temperature control roll at 60 ° C. The laminated laminated film was aged at 40 ° C. for 2 days. The prepared laminated sample was heat-sealed with a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, and a sealing temperature of 120 to 190 ° C. at a pitch of 10 ° C. and a width of 10 mm.
The heat-sealed sample is cut into strips so that the heat-sealing width is 15 mm, set on an autograph (Shimadzu Seisakusho model: UA-3122), and the maximum strength of peeling the sealed surface at a speed of 200 mm / min. The value was measured with n number 3, and the heat seal strength having the highest average value was defined as the reached seal strength.

(14) Blocking Strength A laminated film with a nylon film (Biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) was prepared as follows.
Toyo Morton's dry laminating adhesive (TM569, CAT-10L) is applied to the corona surface of the nylon film so that the solid content is 3 g / m ² , and the solvent is volatilized and removed in an oven at 80 ° C. The corona surface of the film and the adhesive coated surface were niped and laminated on a temperature control roll at 60 ° C. The laminated laminated film was aged at 40 ° C. for 2 days.
A sample (10 cm x 15 cm) in which the measurement surfaces are overlapped is placed 1 cm inside in the length direction (15 cm) at the center of the sample width (10 cm) in a heat press (manufactured by Tester Sangyo Co., Ltd., model: SA-303). A 7 cm x 7 cm aluminum plate (2 mm thick) is placed on top of each other so that the ends are aligned, and pressure treatment is performed at a temperature of 50 ° C., a pressure of 440 kgf / cm ² , and a time of 15 minutes.
When the sample and bar (diameter 6 mm, material: aluminum) blocked by this pressure treatment are attached to the autograph (Shimadzu model: UA-3122) and the bar peels off the blocking part at a speed (100 m / min). The force was measured.
In this case, it is assumed that the bar and the peeling surface are horizontal. The same sample was measured four times and displayed as an average value.

(15) Static Friction Coefficient A laminated film with a nylon film (Biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) was prepared as follows.
Toyo Morton's dry laminating adhesive (TM569, CAT-10L) is applied to the corona surface of the nylon film so that the solid content is 3 g / m ² , and the solvent is volatilized and removed in an oven at 80 ° C. The corona surface of the film and the adhesive coated surface were niped and laminated on a temperature control roll at 60 ° C. The laminated laminated film was aged at 40 ° C. for 2 days. The coefficient of static friction between the polyethylene-based resin film surfaces of the prepared laminated film was measured in an environment of 23 ° C. and 65% RH in accordance with JIS-K7125.

(16) Haze Only 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 (diffusion transmittance%) / Tt (total light transmittance%)] x 100

(17) Feeling of flicker Only the polyethylene-based resin film was visually observed, and the feeling of flicker was classified into the following ⊚, ◯, Δ, and ×.
◎: Almost no bright spots are felt.
◯: There are fine bright spots, but they are uniform and do not bother me.
Δ: There are some bright spots and a foreign body sensation is felt.
X: There are bright spots on the entire surface and transparency is impaired.
(18) Appearance over time Film formation was started after replacing the filter with a filtration accuracy of 60 μm for all layers, and only the polyethylene-based resin film after 7 days was visually observed at n = 3 in A4 size by the film formation method described in the example, and 1000 cm. ^The average value converted into the number of foreign substances around ² was classified into the following ◎, ○, △, and ×.
⊚: 1 gel-like foreign substance of 0.2 mmφ or more and 1 mm or less / less than ² ○: 2 gel foreign substances of 0.2 mmφ or more and 1 mm or less / 1000 cm less than ² Δ: 2 gel foreign substances of 0.2 mmφ or more and 1 mm or less 4 or more / 1000 cm less than ² x: 4 or more gel foreign substances of 0.2 mmφ or more and 1 mm or less / 1000 cm ² or more

(19) A laminated film with a scratch-resistant nylon film (Toyobo biaxially stretched nylon film: N1100, 15 μm) was prepared as follows.
Toyo Morton's dry laminating adhesive (TM569, CAT-10L) is applied to the corona surface of the nylon film so that the solid content is 3 g / m ² , and the solvent is volatilized and removed in an oven at 80 ° C. The corona surface of the film and the adhesive coated surface were niped and laminated on a temperature control roll at 60 ° C. The laminated laminated film was aged at 40 ° C. for 2 days. The polyethylene-based resin films of the prepared laminated film were pinched with fingers so that the surfaces overlapped with each other, rubbed 10 times, visually observed, and the susceptibility to scratches was classified by the following ⊚, ◯, Δ, and ×.
⊚: Almost no scratches.
◯: Fine streak-like scratches are made, but whitening does not occur.
Δ: Fine streak-like density and partial whitening are observed.
X: The rubbed part is almost whitened.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.
The following raw materials were used in Examples and Comparative Examples.
(Polyethylene resin)
(1) 0540F (metallocene-based linear low-density polyethylene, manufactured by Ube-Maruzen Polyethylene Co., Ltd., density 904 kg / m ³ , MFR 4.0, melting point 111 ° C)
(2) FV402 (metallocene linear low density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 913 kg / m ³ , MFR 3.8 g / 10 min, melting point 115 ° C)
(3) FV405 (metallocene linear low density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 923 kg / m ³ , 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 / m ³ , MFR 3.2 g / 10 min, melting point 124 ° C.)
(5) 3540F (metallocene linear low density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 931 kg / m ³ , MFR 4.0 g / 10 min, melting point 123 ° C)
(6) 4540F (metallocene linear low density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 944 kg / m ³ , MFR 4.0 g / 10 min, melting point 128 ° C)
(7) Lubmer LS3000 (high molecular weight polyethylene, manufactured by Mitsui Chemicals, Inc., density 969 kg / m ³ , MFR 14 g / 10 min, thermal deformation temperature (4.6 kg / cm ² ) 80 ° C.)

(Particles made of polyethylene resin)
(1) Miperon XM220 (ultra high molecular weight polyethylene particles, manufactured by Mitsui Chemicals, Inc., density 940 kg / m ³ , melting point 136 ° C., viscosity average molecular weight 2 million, shore hardness 65D, volume average particle size 30 μm, grains exceeding 30 μm Diameter weight ratio 55%)
(2) Miperon PM220 improved product (ultra-high molecular weight polyethylene particles, manufactured by Mitsui Chemicals, Inc., density 940 kg / m ³ melting point 135 ° C., viscosity average molecular weight 1.8 million, shore hardness 65D, volume average particle size 10 μm, exceeding 25 μm Weight ratio of particle size 1% or less)

(Inorganic particles)
(1) KMP-130-10 (spherical silica particles, manufactured by Shinetsu Silicon Co., Ltd., average particle size 10 μm)
(2) Daikalite WF (diatomaceous earth, manufactured by Grefco. Inc., processed to an average particle size of 5 μm with a pin mill crusher)

(Organic lubricant)
(1) Ethylene bisoleic acid amide (using Sumitomo Chemical's ethylene bisoleic acid amide 2% masterbatch EMB11)
(2) Erucic acid amide (using Sumitomo Chemical's erucic acid amide 4% masterbatch EMB10)

(Examples 1 to 6)
The resins and additives shown in Table 1 were used as raw materials for the seal layer, laminate layer, and intermediate layer, each melted at 240 ° C. using three extruders, and filtered through a sintering filter with a filtration accuracy of 60 μm. After that, it was co-extruded from the T-die into a sheet, melt-extruded so that the thickness ratio of the seal layer, the intermediate layer, and the laminate layer was 1: 3: 1, and cooled and solidified with a cooling roll at 30 ° C. to obtain the obtained product. After corona discharge treatment was applied to the surface of the laminated layer of the sheet, the sheet was wound into a roll at a speed of 150 m / min to obtain a polyethylene resin film having a thickness of 50 μm and a wet tension of 45 N / m on the surface of the laminated layer.

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

The polyethylene-based resin film obtained in Example 6 was suitable for heavy bags and the like, and had excellent appearance and scratch resistance, although the blocking resistance and the coefficient of friction varied between the measured values between the measurement samples. Moreover, it was also excellent in film forming workability.

(Comparative Examples 1 to 5)
The resins and additives shown in Table 2 were used as raw materials for the seal layer, laminate layer, and intermediate layer, each melted at 240 ° C. using three extruders, and filtered through a sintering filter with a filtration accuracy of 60 μm. After that, it was co-extruded from the T-die into a sheet, melt-extruded so that the thickness ratio of the seal layer, the intermediate layer, and the laminate layer was 1: 3: 1, and cooled and solidified with a cooling roll at 30 ° C. to obtain the obtained product. After corona discharge treatment was applied to the surface of the laminated layer of the sheet, the sheet was wound into a roll at a speed of 150 m / min to obtain a polyethylene resin film having a thickness of 50 μm and a wet tension of 45 N / m on the surface of the laminated layer.

The film obtained in Comparative Example 1 was excellent in blocking resistance and slipperiness, but had a slight flicker feeling, and was not only inferior in scratch resistance but also inferior in filter pressurization and film forming workability. ..
Although the film obtained in Comparative Example 2 was excellent in blocking resistance and slipperiness, it had a flicker feeling and was inferior in appearance.
The film obtained in Comparative Example 3 was excellent in blocking resistance and transparency, but had a severe flicker feeling and was significantly inferior in appearance.
The film obtained in Comparative Example 4 had uneven melting on the surface, had a flicker feeling, and had a significantly inferior appearance. In addition, blocking resistance, slip resistance, and scratch resistance were also inferior.
Although the film obtained in Comparative Example 5 had excellent blocking resistance, it had a flicker feeling and was inferior in appearance. Moreover, the scratch resistance and the film forming processability were inferior.

(Comparative Examples 6 and 7)
The resins and additives shown in Table 2 are used as raw materials for the seal layer, laminate layer, and intermediate layer, and each is melted at 240 ° C. using three extruders, and a sintered filter with a filtration accuracy of 200 μm and 120 μm. After filtering with, it is co-extruded from the T-die into a sheet, melt-extruded so that the thickness ratio of the seal layer, the intermediate layer, and the laminate layer is 1: 3: 1, and then cooled and solidified with a cooling roll at 30 ° C. After corona discharge treatment was applied to the surface of the laminated layer of the obtained sheet, it was wound into a roll at a speed of 150 m / min to obtain a polyethylene resin film having a thickness of 50 μm and a wet tension of 45 N / m on the surface of the laminated layer.

The polyethylene-based resin films obtained in Comparative Examples 6 and 7 had excellent heat-sealing properties, small fluctuations in the measured values between the measurement samples in terms of blocking resistance and friction coefficient, and stable blocking resistance and slipperiness. .. Moreover, it was excellent in scratch resistance and film forming workability. However, the presence of the appearance gel-like substance increased with time, and it was inferior to Examples 1 to 6.
The results are shown in Tables 1 and 2.

Although the method for producing the polyethylene-based resin film of the present invention has been described above based on a plurality of examples, the present invention is not limited to the configuration described in the above examples, and the configuration described in each example is used. The configuration can be changed as appropriate within the range that does not deviate from the purpose, such as by appropriately combining the above.

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

Claims (3)

A step of melt-kneading a polyethylene resin composition containing polyethylene-based resin particles and a polyethylene-based resin, a step of melt-extruding the polyethylene resin composition to obtain a molten polyethylene resin composition sheet, and cooling the molten polyethylene resin composition sheet. A method for producing a polyethylene resin film, which comprises a step of solidifying and filtering the polyethylene resin composition using a filter having a filtration accuracy of 100 μm or less in the step of melt-kneading. The method for producing a polyethylene-based resin film according to claim 1, wherein the polyethylene-based particles have a viscosity average molecular weight of 1.5 million or more and a melting point peak temperature by DSC is 150 ° C. or lower. The method for producing a polyethylene-based resin film according to claim 1 or 2, wherein the filtration accuracy of the filter is 80 μm or less.