KR20200077567A - Manufacturing method of polyethylene resin film - Google Patents

Abstract

An object of the present invention is to efficiently and stably produce a polyethylene-based resin film excellent in heat sealing properties and also excellent in appearance and scratch resistance.
In order to solve the above problems, the method of manufacturing a polyethylene-based resin film of the present invention comprises the steps of melt-kneading a polyethylene resin composition containing particles made of a polyethylene-based resin and a polyethylene-based resin, and melt-extruding the polyethylene resin composition to melt polyethylene. It includes the process of making a resin composition sheet, and the process of melt-kneading the said polyethylene resin composition, and filtering using a filter of 100 micrometers or less in filtration precision in the process of melt-kneading the said polyethylene resin composition.

Description

Manufacturing method of polyethylene resin film

The present invention relates to a method for producing a polyethylene-based resin film. More particularly, the present invention relates to a method for producing a polyethylene-based resin film that is excellent in stable blocking resistance or stable sliding property, 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 reduction of load on the environment. The film has the advantages of light weight, easy disposal, and low cost compared to conventional molding containers and molded products.

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, or a biaxially stretched polypropylene film, which has lower thermal adhesion than the sealant film. When stored in roll form after these base films and laminate processing, blocking may occur between the sealant film and the base film, making it difficult to rewind the laminate film before umbilical processing, or sealant that becomes the inner surface of the bag during umbilical processing In some cases, blocking occurred between the films, making it difficult to fill the food.

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

However, this measure not only contaminates the periphery of the film processing apparatus, but also significantly deteriorates the appearance of the packaged food, or the powder adhered to the sealant film is directly incorporated into the package with the food, or the heat sealing strength is deteriorated. Was causing problems.

Thus, polyethylene-based resin films using inorganic fine powders or inorganic fine particles such as silica have been reported for polyethylene-based resins (for example, see Patent Document 1).

However, in the case of this measure, scratches are likely to occur when the surfaces of films containing inorganic fine powders or inorganic particles such as alumina or silica added to a polyethylene film are rubbed against each other, and a laminate or umbilical processing machine is used as a sealant film or substrate. When the laminate with the film passed, there was also a problem that the inorganic fine powder or the inorganic particles were liable to fall off upon contact with a part of the machine (for example, see Patent Document 1).

Moreover, a polyethylene-based resin film using organic crosslinked particles comprising a copolymer containing an acrylic monomer and a styrene-based monomer as a main component has been reported (for example, see Patent Document 1).

However, in the case of this measure, the ease of occurrence of scratches is not as bad as that of inorganic particles, but cannot be said to be sufficient. In addition, the problem of anti-blocking and particle dropping remained.

Further, when the polyethylene raw material resin composition is melt-kneaded and extruded into a sheet, the polyethylene resin is decomposed, and it is indispensable in quality control to filter the cross-linked organic material produced as a result of recombination and so-called gel using a filter. At this time, since the inorganic particles and the crosslinked organic particles aggregated and clogged the filter, the filter had to be replaced, so that there was a problem in that operation efficiency was lowered and cost increased. In addition, prior to the extrusion speed, when a filter with a low filtration precision was used, so-called gel removal was insufficient, and there was a problem that the quality of the gel deteriorated due to an increase in gel defects over time.

Japanese Patent Publication No. Hei 10-86300

The present invention aims to efficiently and stably produce a polyethylene-based resin film excellent in heat sealing properties, appearance and scratch resistance, and having less dropping of particles.

The present inventors, in view of such a fact, have studied in earnest, found that the above problem can be solved by using a polyethylene resin-based particle and using a filter with high filtration precision to produce a polyethylene resin film. The invention has been solved.

That is, the present invention is a process of melt-kneading a polyethylene resin composition containing particles of a polyethylene-based resin and a polyethylene-based resin, a process of melt-extruding the polyethylene resin composition to a molten polyethylene resin composition sheet, and cooling the molten polyethylene resin composition sheet. It is a manufacturing method of a polyethylene-based resin film including a step of solidifying and filtering using a film having a filtration accuracy of 100 µm or less in the step of melt-kneading the polyethylene resin composition.

In this case, it is suitable that the particles made of the polyethylene-based 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.

Further, 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 excellent in heat sealing properties and also excellent in appearance and scratch resistance can be efficiently and stably produced.

(Particles made of polyethylene resin)

The particles made of the 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 even more preferably 1.7 million or more. Moreover, 2.5 million or less is preferable, it is more preferable that it is 2.4 million or less, and it is still more preferable that it is 2.3 million or less.

If it is the viscosity average molecular weight in this range, the maximum acid height of at least one surface layer of the obtained film can be 2 micrometers or more and 15 micrometers or less. The reason is not clear, but the molecules are not mixed because the difference between the molecular weight of the polyethylene resin and the polyethylene resin other than the particles of the polyethylene resin is very large, and even in the film obtained by melt mixing and extrusion, polyethylene Since it is easy to maintain the shape of the particles made of a resin based on the resin, and it is difficult to aggregate by fusion or adhesion between particles, it is presumed that projections suitable for the particle diameter can be formed on the film surface in the same manner as inorganic particles. have.

If the viscosity-average molecular weight of the particles made of polyethylene-based resin is less than 1.5 million, when the temperature at the time of melt mixing is higher than the melting point peak, decomposition by heat or shear or fusion bonding, or particle shape by partial compatibility with the base resin Since changes occur, it is impossible to form protrusions such as conventional inorganic particles or organic crosslinked polymer beads, and the function as an anti-blocking agent is not only insufficient, but also affects appearance such as transparency, mechanical strength of the film, or heat sealing property. Crazy

Moreover, when the viscosity average molecular weight exceeds 2.5 million, it is easy to maintain the particle shape when melt-mixing and extruding to form a film, in which case, it is difficult to form a suitable film surface protrusion.

In addition, this is surprising, even though the particles made of polyethylene resin having a viscosity average molecular weight of 1.5 million or more are hard to agglomerate, other polyethylene-based resins mixed therewith are characterized by being more difficult to fall off than inorganic particles. It was found to have.

In addition, if the viscosity-average molecular weight of the particles made of polyethylene-based resin is 1.5 million or more, the particles themselves have lubricity, contributing to the improvement of blocking and slipping properties, and the particles made of polyethylene-based resin are soft, so that the scratch resistance is also improved. I think.

The average particle diameter of the particles made of the polyethylene resin used in the present invention is preferably 2 µm or more, more preferably 3 µm or more, and even more preferably 5 µm or more. Moreover, 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 to this, it is preferable not to include particles having a particle diameter of 25 µm or more. Even if the average particle diameter is 20 µm or less, when the particles having a particle diameter of 25 µm or more contain 1% or more, the maximum acid height of the film surface tends to exceed 15 µm. Then, when the film surface is observed with the naked eye, flicker described later occurs.

In addition, particles having a size of 25 µm or more are also undesirable in that they become defects and deteriorate in quality.

(Polyethylene resin)

Polyethylene-based resins other than "particles made of polyethylene-based resin" in the present invention are homopolymers of ethylene monomers, copolymers of ethylene monomers and α-olefins, and mixtures thereof, and propylene and butene-1 as α-olefins. , Hexene-1, 4-methylpentene-1, octene-1, decene-1, and the like.

The density range of the polyethylene-based resin other than the particles made of the polyethylene-based resin in the present invention is not particularly limited, but 900 to 940 kg/m 3 is preferable in order to obtain a polyethylene-based resin film having both heat sealing and blocking resistance. , 905 to 935 kg/m 3 is more preferable, 910 to 930 kg/m 3 is more preferable, and 915 to 925 kg/m 3 is particularly preferable. For polyethylene-based resins having a density of less than 900 kg/m 3, blocking resistance is likely to decrease.

Polyethylene-based resins having a density greater than 940 ㎏/㎥ have a high heat sealing initiation temperature, making it difficult to discharge, and transparency is poor, but when polyethylene-based resins with a density greater than 940 ㎏/㎥ are used, packing heavy materials The present invention is very effective for producing a polyethylene resin film having excellent strength by lowering the frequency of exchange of filters, or for producing a film with few defects.

The blocking resistance is heat-pressed (sample model manufactured by Tester Industries Co., Ltd.: SA-303) on a sample that sandwiches the measuring surfaces of the film, and is subjected to a pressure treatment of size 7 cm×7 cm, temperature 50° C., pressure 440 kgf/cm 2, and time 15 minutes. To do. The sample and bar (diameter 6 mm, material: aluminum) blocked by this pressurization treatment were mounted on an autograph (model manufactured by Shimadzu Corporation: UA-3122) so that the bar and the peeling surface were horizontal, and the bar speed (100 m/min.) ) To measure the force at the time of peeling off the blocking section 4 times, and use the average value as an index, but when a polyethylene resin having a density greater than 0.940 g/m 3 is used, it is likely to fluctuate in each measurement value measured 4 times. In addition, a tendency to increase the heat sealing start temperature was confirmed. It is preferable that the fluctuation of each measured value of four measurements is at a level equivalent to the case where 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-based resin is the base, the viscosity-average molecular weight of the particles made of the polyethylene-based resin decreases or polyethylene-based resins other than the particles made of the polyethylene-based resin. It is presumed that a change in particle diameter due to interlocking of the molecular chain with and the like occurs as a result of which the projections on the surface to be formed 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, sometimes referred to as MFR) is preferably 2.5 to 10 g/min in terms of film forming properties and the like. Here, MFR was measured based on JIS K7210. Alternatively, the polyethylene-based resin is synthesized by a self-known method.

In the case of using a resin having a MFR of 2.5 g/10 minutes or less of a polyethylene resin other than the particles made of the polyethylene resin in the present invention, the viscosity average of the particles made of the polyethylene resin is similar to the description in density. Since the particle size changes due to molecular weight reduction or interlocking of molecular chains with polyethylene-based resin other than particles made of polyethylene-based resin are liable to occur, care must be taken in extrusion conditions. In the case of high-speed film forming with a large-scale film forming machine, MFR is preferably 3 to 4 g/10 minutes for film forming properties.

As the polyethylene-based resin other than the particles made of the polyethylene-based resin in the present invention, in terms of heat resistance and the like, the melting point is preferably 85°C or higher, more preferably 100°C or higher, and particularly preferably 110°C or higher.

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

As a polyethylene-based resin other than particles made of a polyethylene-based resin having a density of 900 to 940 kg/m 3 as described above, a high-pressure method low-density polyethylene (LDPE) that is transparent, has high flexibility, and has excellent tear strength and tensile strength on average. ), butene-1·hexene-1 octene-1 is copolymerized in a small amount, and has a large number of single-molecular chains in the molecular chain, and exhibits a very sharp molecular weight distribution, linear short-chain branched polyethylene (LLDPE) having excellent sealing performance and physical strength, The distribution of the comonomer is uniform, and metallocene catalyst linear short-chain branched polyethylene (LLDPE) having excellent tear, tensile, stiffness, and pinhole properties can be selected according to the application.

As an addition amount of the particle|grains which consist of polyethylene resin in this invention, it is preferable that it is 0.1 weight% or more with respect to the whole film, 0.3 weight% or more is more preferable, and 0.4 weight% or more is more preferable. Moreover, 2 weight% or less is preferable, 1.5 weight% or less is more preferable, and 1.0 weight% or less is more preferable. When the addition amount of the particles made of a polyethylene-based resin is less than 0.1% by weight, it is difficult to set the maximum acid height of at least one surface layer of the obtained film to 2 µm or more per designated area (0.2 mm 2 ), and it is difficult to obtain anti-blocking properties and slip properties. Lose. In addition, when the addition amount of the particles made of a polyethylene-based resin is more than 2% by weight, the protrusions on the surface become large, the transparency is poor, and the low-temperature sealing property tends to fall.

To the polyethylene-based resin film in the present invention, known additives, for example, antioxidants, neutralizing agents, organic lubricants, anti-static agents, and antistatic agents, may be used in combination within the range not impairing the objects and effects of the present invention. The blending of 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 resin film in the present invention. The slipping property and anti-blocking effect of the laminated film are improved, and the handleability of the film is improved. For this reason, it is thought that the lubricant effect and the release effect were expressed when the organic lubricant was bleeded out and existed on the film surface. In addition, it is preferable to add an organic lubricant having a melting point above room temperature. Organic lubricants include fatty acid amides and fatty acid esters. Specifically, oleic acid amide, erucic acid amide, behenic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, ethylenebisoleic acid amide, and the like. Although these may be used alone, a combination of two or more types is preferable because they can maintain the slipping property and the anti-blocking effect even in an excessively harsh environment.

The lower limit of the concentration of the organic lubricant amide in the layer containing particles of the film or polyethylene resin of the present invention is preferably 200 ppm, and more preferably 400 ppm. If it is less than the above, slippage may deteriorate. The upper limit of the concentration of the organic lubricant amide is preferably 2,500 ppm, more preferably 2,000 ppm. If it exceeds the above, it is too undesirable to slip.

Further, ethylene/vinyl acetate copolymers, ethylene/acrylic acid ester copolymers, etc. may be mixed and used within a range not impairing the objects and effects of the present invention.

In the polyethylene-based resin film in the present invention, it is necessary to contain substantially no inorganic particles. When the inorganic particles are substantially contained, the effect of adding particles made of a polyethylene resin such as scratch resistance and particles not falling out is not only difficult to obtain, but rather, when a filter with high filtration accuracy is used, the filter boosting pressure is increased. It is fast, and there is a decrease in operability due to filter replacement. The inorganic particles referred to herein are inorganic materials generally used as an anti-blocking agent such as silica, talc, calcium carbonate, diatomaceous earth, zeolite, etc., and the content of the inorganic particles in the entire polyethylene-based resin film of the present invention is substantially free. 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 the crosslinked organic particles are substantially contained, it is difficult to obtain the effect of adding particles made of a polyethylene resin such as scratch resistance and particles not falling off. The crosslinked organic particles referred to herein are crosslinked particles typified by polymethyl acrylate resin and the like, and substantially not contained means that the ratio of the amount of crosslinked organic particles in the 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.

(Production method)

As a method for producing the polyethylene-based resin film of the present invention, for example, a process of melt-kneading a polyethylene-based resin composition containing polyethylene-based resins other than particles made of a polyethylene-based resin and particles made of a polyethylene-based resin, melt-kneaded It is preferable to employ the step of melt-extruding the resin composition into 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 a laminate. In the case of lamination, it is possible to provide another layer different from a layer containing particles made of a polyethylene resin and having a maximum acid height of at least one surface layer of 2 µm or more and 15 µm or less.

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 particularly preferably 20 µm or more. Moreover, 200 micrometers or less are preferable, 150 micrometers or less are more preferable, 100 micrometers or less are especially preferable. In the case of less than 3 µm, the effect of the particles made of a polyethylene-based resin is lowered, so that the effect of blocking resistance and slipping is difficult to be exhibited.

The thickness of the layer containing at least one surface layer having a maximum acid height of 2 µm or more and 15 µm or less is preferably 3 µm or more, more preferably 10 µm or more, and more preferably 15 µm, containing particles made of a polyethylene resin in the case of lamination. The above is more preferable, and 20 µm or more is particularly preferable. Moreover, 200 micrometers or less are preferable, 150 micrometers or less are more preferable, 100 micrometers or less are especially preferable. In the case of less than 3 µm, the effect of the particles made of a polyethylene-based resin is lowered, so that the effect of blocking resistance and slipping is difficult to be exhibited.

(Material mixing process)

In the case of mixing particles made of a polyethylene-based resin and polyethylene-based resins other than particles made of a polyethylene-based resin, any method may be used to uniformly mix them, and when using a masterbatch, a ribbon blender, a Henschel mixer, a tumbler mixer, etc. And mixing using the same. In the case of direct addition, particles made of polyethylene resin may be attached to the resin to which the impregnating agent is attached, or may be added directly to the extruder with a side feed or the like.

The method of mixing a small amount of a masterbatch made by mixing particles made of a polyethylene resin with a high concentration, and a polyethylene resin other than particles made of a polyethylene resin, with a polyethylene resin other than particles made of a polyethylene resin is also used for dispersibility. Good and simple. However, when a particle composed of a polyethylene resin is mixed with a straight-chain low-density polyethylene, a homopolymer of ethylene monomer, or a copolymer of ethylene monomer and α-olefin without using a master batch, high dispersibility is obtained. , For cost, direct addition by a side feed method or the like is preferred.

(Melting kneading process)

First, as a film raw material, drying or hot air drying is performed so that the moisture content of the particles made of polyethylene-based resin and the polyethylene-based resin other than particles made of polyethylene-based resin is less than 1,000 ppm. Subsequently, each raw material is metered and mixed, supplied to an extruder, and melt-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 even 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. When it exceeds the above, the decomposition of the resin composition proceeds, and the amount of foreign substances such as cross-linked organic substances and so-called gels generated 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 becomes possible, but is preferably 270°C or lower.

Although the melting point of the particles made of the polyethylene-based resin used in the present invention is about 150° C. or less, and mixed with polyethylene-based resins other than the particles made of the polyethylene-based resin, even though it is much lower than the temperature at the time of melt-kneading, surprisingly, “polyethylene Particles composed of polyethylene resins” on the polyethylene resin film obtained by extruding from a T-die and cooling process without dispersing to a polyethylene resin other than the molecular level. It exists while maintaining the particle diameter and shape before addition to the polyethylene-based resin.

(percolation)

In the melt-kneading step, high-precision filtration can be performed to remove foreign substances contained in the melted polyethylene-based resin composition. The filter medium used for the high-precision filtration of the molten resin is not particularly limited, but in the case of a filter medium of a stainless sintered body, Si, Ti, Sb, Ge, and Cu derived from additives such as a catalyst are added in addition to foreign substances such as gels. It is suitable because it has excellent removal performance of aggregates. 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-based resin in the present invention are melted during melt-kneading, it is not only impossible to filter with a high-precision filter medium, but also has a small advantage in that the pressure increase due to clogging is less than that of inorganic particles because there are few coarse particles. There is this. In addition, by reducing the average particle size of the particles made of polyethylene-based resin or narrowing the particle size distribution, even if it is industrially produced with a high-precision filter medium having a filtration precision of 60 µm or less, there is little clogging, and foreign matter can be eliminated. It also has the advantage that it does not impair the blocking resistance obtained by particles made of a polyethylene-based resin.

The filtration accuracy referred to herein is a nominal filtration accuracy, and has a capability of capturing particles having a size equal to or greater than the display filtration accuracy (for example, particles having a filtration accuracy of 60 µm or more and 60 µm or more) by 60% or more. Absolute filtration accuracy is the ability to capture particles with a size greater than or equal to the display filtration accuracy of 99.9% or more. Even if it is nominal filtration accuracy, it is preferable that it is close to absolute filtration accuracy as performance.

(Filter boosting)

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

(Melt extrusion process)

Next, the melted polyethylene-based resin composition sheet is melt-extruded from, for example, a T-type 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 onto a cooling roll.

Since the particles made of the polyethylene-based resin used in the present invention are hydrophobic resins from the beginning, the hydrophobicity of the surface of the particles does not change even through a melt-kneading and extrusion process, and the lip of the T-type dice seen in the inorganic particles hydrophobized the surface. It is very difficult for sedimentation of thermal deterioration, so-called globule, at.

A method of melt-extruding a sheet of a melted polyethylene-based resin composition to make an object into a film by a T-die method or an inflation method is mentioned, and the T-die method is particularly preferable because the melting temperature of the resin composition can be increased.

(Lip contamination)

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

(Cooling and solidification process)

For example, it is preferable to perform cooling by casting a molten sheet of a polyethylene-based resin composition melt-extruded from a T-type die onto 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 not only be saturated, but also problems such as 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 is too high, and the appearance may be deteriorated. In addition, 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 to prevent condensation.

In the case of casting, the temperature of the cooling roll surface rises because the hot resin comes into contact with the surface. In addition, the cooling roll cools by flowing cooling water through the piping inside, securing a sufficient amount of cooling water, devising a piping arrangement, and performing maintenance such that sludge does not adhere to the piping, thereby reducing the temperature difference in the width direction of the cooling roll surface. You need to do less. 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 multi-layer, in addition to a layer containing particles of the above-mentioned polyethylene-based resin and having a maximum acid height of at least one surface layer of 2 µm or more and 15 µm or less, another layer may be provided in one layer or two or more layers.

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

For example, it is possible to use a method in which a thermoplastic resin sent from different flow paths using two or more extruders is laminated in multiple layers using a feed block, a static mixer, a multi-manifold die, or the like. Further, it is also possible to introduce the above-described multilayering apparatus into the meltline from the extruder to the T-type die using only one extruder.

In the case of the three-layer configuration, the layer containing polyethylene resin is used, and the layer having at least one surface layer having a maximum acid height of 3 µm or more and 15 µm or less is used as the sealing layer (A layer), and the other layers are respectively intermediate layers (B layer). ), a laminate layer (layer C), and a structure included in this order is preferred.

The outermost layers are A and C layers, respectively.

Examples of the polyethylene resin using an intermediate layer (layer B) and a laminate layer (layer C) include, for example, a mixture of one or two or more selected from ethylene/α-olefin copolymers 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 as the α-olefin, butene-1, hexene-1, 4-methylpentene-1, octene-1, and decene-1 And the like.

Films obtained from these polyethylene-based resins have excellent heat-sealing strength, hot-tack properties, contaminant sealing properties, and impact resistance, and the polyethylene-based resins do not impair these properties, and other resins, such as ethylene/vinyl acetate copolymer You may mix and use a coalescence, an ethylene-acrylic acid ester copolymer, etc.

At this time, the polyethylene-based resin used for the intermediate layer (layer B) and the laminate layer (layer C) may be the same or different. Further, particles made of a polyethylene-based resin may or may not be added. However, it is substantially free of inorganic particles and organic crosslinked particles. By not containing substantially, it means that the ratio of the amount of crosslinked organic particles in the 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-based resin of each layer of the film is a sealant layer (A layer) ≤ intermediate layer (B layer) ≤ laminate layer (C layer). Since the blended organic lubricant is difficult to move to a dense layer, it is effective to maintain the slip property after lamination.

At this time, the lower limit of the density of the intermediate layer (layer B) and the laminate layer (layer C) is preferably 900 kg/m 3, more preferably 920 kg/m 3, and even more preferably 930 kg/m 3. If it is less than the above, the stiffness is weak, and processing may be difficult.

The upper limit of the density of the intermediate layer (layer B) and the laminate layer (layer C) is preferably 960 kg/m 3, more preferably 940 kg/m 3, and even more preferably 935 kg/m 3.

The above-mentioned organic lubricant may be used for the intermediate layer (layer B) 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, slippage may deteriorate.

The upper limit of the concentration of erucamide in the intermediate layer (layer B) is preferably 2,000 ppm, more preferably 1,500 ppm. If it exceeds the above, it may cause excessive slipping and winding.

You may mix|blend 10-30 mass% of recovery resin in the intermediate|middle layer (layer B) of the polyethylene resin film in this 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. The laminate strength is improved by this correspondence.

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

(Maximum projection height)

It is necessary that the maximum acid height of at least one surface layer of the polyethylene-based resin film of the present invention is 2 µm or more and 15 µm or less. When the maximum acid height Rz exceeds 15 μm, it is not preferable because it causes poor appearance. The measuring method is carried out by the method described in Examples.

(Number of protrusions over 15 μ)

In the polyethylene resin film according to the present invention, it is preferable that the number of protrusions (pieces/0.2 mm 2) exceeding 15 µm in a surface layer having a maximum acid height of 2 µm or more and 15 µm or less on the surface is 0 or less. The smaller the number, the lower the appearance of flicker or haze. The measuring method is carried out by the method described in Examples.

(Heat sealing start temperature)

The upper limit of the heat sealing 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. When it exceeds the above, sealing processing may become difficult. The measuring method is carried out by the method described in Examples.

(Reach heat sealing strength)

The lower limit of the reach heat sealing strength at 120°C of the polyethylene-based resin film laminated with a 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 easily break after being discharged.

The upper limit of the reach heat sealing strength 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, the bag may be difficult to open after being discharged. The measuring method is carried out by the method described in Examples.

(Blocking strength)

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

(Friction strength)

The lower limit of the static friction coefficient after lamination of the polyethylene-based resin film laminated with the biaxially stretched nylon film (15 µm) is preferably 0.05, and more preferably 0.08. If it is less than the above, the film may slip excessively during winding and may cause misalignment.

The upper limit of the static friction coefficient after lamination is preferably 0.50, and more preferably 0.4. When the above is exceeded, the openability after discharge is poor, and the loss during processing may increase. The measuring method is carried out by the method described in Examples.

(Haze)

The lower limit of haze of the polyethylene-based resin film of the present invention is preferably 3%, more preferably 4%, even more preferably 5%. If it is less than the above, there is a fear that the 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%. When it exceeds the above, it may be difficult to visually recognize the contents. The measuring method is carried out by the method described in Examples.

(Flickr feeling)

It is preferable that the polyethylene-based resin film of the present invention hardly feels flicker, or has some fine flicker, but is uniform and does not particularly care. The measuring method is carried out by the method described in Examples.

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

(Scratch resistance)

The polyethylene-based resin film laminated with a biaxially stretched nylon film (15 µm) is hardly scratched or finely streaked, but not whitened, even after rubbing it 10 times with a finger so that the sealing surfaces overlap. desirable. The measuring method is carried out by the method described in Examples.

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

(Young's modulus)

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

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

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

Example

The present invention will be described in more detail by Examples and Comparative Examples below, but the present invention is not particularly limited by the Examples below. In addition, the measured values of each item in the detailed description and examples of the present invention were measured by the following method.

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

(1) Method for measuring particles made of polyethylene resin

The particles made of polyethylene resin were measured for each physical property of the raw material resin before processing.

In addition, after film molding, decane is used as a solvent to dissolve the film at a temperature at which polyethylene other than particles made of a polyethylene resin is completely dissolved, and the residue is filtered through a filter having a filter filtration accuracy of 2 μm, or decane. After the particles are completely melted, it is also possible to separate and measure the particles made of a polyethylene resin by a method such as separating a portion having a high molecular weight by GPC or the like.

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

It measured according to ASTM-D4020.

(3) Average particle diameter of particles made of polyethylene-based resin

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

After dispersing the particles in ion-exchanged water stirred using a high-speed stirrer at a predetermined rotational speed (about 5,000 rpm), and then adding the dispersion to isotone (physiological saline) to further disperse it with an ultrasonic disperser, the Coulter counter method The particle size distribution was determined and calculated as the volume average particle diameter.

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

The proportion of particles having a particle diameter of 25 µm or more among the particles made of polyethylene resin before use was calculated from the particle size distribution obtained by the Coulter counter method.

(5) Melting point of particles made of polyethylene-based resin

The melting point of the particles made of polyethylene resin before use was measured by 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, melting point of polyethylene-based resins other than particles made of polyethylene-based resins

Each raw material before film molding was measured by the following method.

In addition, the polyethylene-based resin other than the particles made of the polyethylene-based resin, which forms a layer comprising the particles made of the polyethylene-based resin, is confirmed by an electron microscope or the like in the entire layer if it is a single layer, or a layer, and then the surface is less than the thickness of the surface layer. It can be similarly measured by removing the solvent from the filtered solution obtained in the above (1) by scraping with. In the case of shaving from lamination, it can be performed relatively easily by laminating with a polyethylene terephthalate (PET) film or the like and then shaving with a razor or the like.

(density)

It was measured by the density gradient pipe method according to JIS-K7112.

(Melt flow rate: MFR) (g/10 min)

It measured at 190 degreeC of temperature according to JIS-K7210.

(Melting point)

Using a differential scanning calorimeter (DSC) manufactured by SII, the sample was measured at a rate 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 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.

In addition, after film molding, a method such as filtering the residue with a filter having a filter filtration accuracy of 2 μm by dissolving the film at a temperature at which polyethylene other than particles made of a polyethylene resin is completely dissolved using decane as a solvent. It is also possible to measure by separating the inorganic particles.

(8) Filter boosting (film forming processability)

When the resin composition used for the sealing layer was discharged for 5 hours at a discharge rate of 1 kg/hour in a 81 π square millimeter of filtration area, using a Trauton tester at a resin temperature of 230°C in a Naslon sintered filter having a filtration precision of 60 µm. Based on the step-up amount (Δ㎫) of (Δ㎫), it was classified as ◎, ○, △, × below.

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

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

(Triangle|delta): The boosting amount is equivalent to Comparative Example 1.

X: The boosting amount 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 a strand die with an extruder for 5 hours, the contamination of the lip was observed with the naked eye, and as a reference (△), the following ◎, ○, △, × Classified.

◎: Almost no lip contamination can be confirmed.

○: Lip contamination is somewhat observed.

△: Lip contamination can be clearly identified.

×: Lip contamination grew and a streak-like spot was formed on the strand.

(10) Maximum projection height

3D surface roughness SRa uses contact surface roughness (manufactured by Kosaka Research Institute, model ET4000A), and measures surface roughness at a location of 1 mm × 0.2 mm at random measuring points from 3 cm × 3 cm film pieces. The mountain height Rz was determined. Rz measured by the above method was measured at n=3 to obtain an average value.

(11) Number of protrusions over 15 μm (pieces/0.2 mm 2)

For the number of protrusions of 15 μm or more, contact surface roughness (model ET4000A manufactured by Kosaka Research Institute) was used to randomly measure the surface roughness of the sealing layer at a location of 1 mm × 0.2 mm from a piece of film 3 cm×3 cm in all directions. The projections were obtained by marking projections 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 calculated from the average of n=3 measured values.

(12) Heat sealing start temperature (℃)

On a corona surface of a nylon film (biaxially stretched nylon film manufactured by Toyobo: N1100, 15 µm), a dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Motone was applied to a solid content of 3 g/m 2 in an oven at 80° C. After volatilization of the solvent, the corona surface of the polyethylene-based resin film and the coated surface of the adhesive were laminated by nipping on a temperature control roll at 60°C. The laminated laminated film was aged at 40°C for 2 days. The produced laminated sample was subjected to heat sealing 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 with a width of 10 mm.

The heat-sealed sample was cut into a rectangular shape so that the heat-seal width was 15 mm, and set on an autograph (Shimadzu Corporation model: UA-3122) to obtain the maximum value of the strength at which the sealing surface was peeled off at a rate of 200 mm/min. Measured by n number 3, 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 connected between each plot in a straight line to be the heat sealing starting temperature.

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

On a corona surface of a nylon film (biaxially stretched nylon film manufactured by Toyobo: N1100, 15 µm), a dry laminate adhesive (TM569, CAT-10L) manufactured by Toyo Motone was applied to a solid content of 3 g/m 2 in an oven at 80° C. After volatilization of the solvent, the corona surface of the polyethylene-based resin film and the coated surface of the adhesive were laminated by nipping on a temperature control roll at 60°C. The laminated laminated film was aged at 40°C for 2 days. The produced laminated sample was subjected to heat sealing with a sealing pressure of 0.1 Pa, a sealing time of 0.5 seconds, and a sealing temperature of 120 to 190°C at a pitch of 10°C with a width of 10 mm.

The heat-sealed sample was cut into a rectangular shape so that the heat-seal width was 15 mm, and set on an autograph (Shimadzu Corporation model: UA-3122) to obtain the maximum value of the strength at which the sealing surface was peeled off at a rate of 200 mm/min. By measuring with n number 3, the heat sealing strength with the highest average value was made into the reach sealing strength.

(14) Blocking strength

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

Toyo Morton's dry laminate adhesive (TM569, CAT-10L) was applied to the corona side of the nylon film so that the solid content was 3 g/m 2, and the solvent was volatilized and removed in an oven at 80° C., and then corona side of the polyethylene resin film. The coated surface of the adhesive was laminated by nipping on a temperature control roll at 60°C. The laminated laminated film was aged at 40°C for 2 days.

A sample (10 cm×15 cm) with measuring surfaces interposed therebetween was heat-pressed (Tester Industries Co., Ltd., model: SA-303), from the center of the sample width (10 cm) to the inside of 1 cm in the longitudinal direction (15 cm). The aluminum plate (2 mm thick) of size 7 cm x 7 cm is placed on the position as if it is 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 mounted on an autograph (manufactured by Shimadzu Corporation: UA-3122) and the bar is peeled at a speed (100 m/min). Force was measured.

In this case, the premise is that the bar and the 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 manufactured by TOYOBO: N1100, 15 µm) was produced as follows.

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

(16) Hayes

Only the polyethylene resin film was measured according to JIS-K7105 using a direct read haze meter manufactured by Toyo Seiki Co., Ltd.

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

(17) Flicker feeling

Only the polyethylene-based resin film was observed with the naked eye, and the flicker feeling was classified into ◎, ○, △, × below.

◎: I hardly feel the bright spot.

○: There is a fine bright spot, but it is uniform and does not particularly care.

(Triangle|delta): There is a bright spot partially, and a foreign body feels.

×: There is a bright spot on the front surface, and transparency is impaired.

(18) appearance over time

After replacing the filter with a filtration accuracy of 60 µm in all layers, film formation was started, and only the polyethylene-based resin film after 7 days was visually observed with an A4 size of n=3 after the film formation method described in Example, and the average value converted into the number of foreign substances per 1,000 cm 2 was as follows. ◎, ○, △, ×.

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

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

△: 2 or more, 4 or less, less than 1,000 ㎠ of gel foreign substances of 0.2 mmφ or more and 1 mm or less

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

(19) Scratch resistance

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

Toyo Morton's dry laminate adhesive (TM569, CAT-10L) was applied to the corona side of the nylon film so that the solid content was 3 g/m 2, and the solvent was volatilized and removed in an oven at 80° C., and then corona side of the polyethylene resin film. The coated surface of the adhesive was laminated by nipping on a temperature control roll at 60°C. The laminated laminated film was aged at 40°C for 2 days. The polyethylene-based resin film of the produced laminated film was rubbed 10 times with a finger so as to overlap each other, and the ease of occurrence of scratches was visually observed and classified as ◎, ○, △, × below.

◎: Scratch hardly occurs.

○: Fine streak-like flaws are formed, but whitening does not occur.

(Triangle|delta): Dense stripes of a fine stripe shape and partial whitening are seen.

×: The rubbed portion 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 low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 904 ㎏/㎥, MFR 4.0, melting point 111°C)

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

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

(4) FV407 (Metallocene-based low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 930 ㎏/㎥, 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 ㎏/㎥, MFR 4.0 g/10 min, melting point 123°C)

(6) 4540F (Metallocene-based low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 944 ㎏/㎥, 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 deflection temperature (4.6 kg/cm 2) 80℃)

(Particles made of polyethylene resin)

(1) Mifelon XM220 (Ultra High Molecular Weight Polyethylene Particles, manufactured by Mitsui Chemicals Co., Ltd., density 940 ㎏/㎥, melting point 136°C, viscosity average molecular weight 2 million, Shore hardness 65D, volume average particle diameter 30 μm, exceeding 30 μm Grain weight ratio 55%)

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

(Inorganic particles)

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

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

(Organic lubricant)

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

(2) Eruxanamide (Eruxanamide 4% masterbatch EMB10 manufactured by Sumitomo Chemical was used)

(Examples 1 to 6)

The resins and additives shown in Table 1 were used as raw materials for the sealing layer, the laminate layer, and the intermediate layer, and each was melted at 240°C using three extruders, filtered through a sintered filter having a filtration precision of 60 µm, and T After coextrusion from the die into a sheet, melt-extruding such that the thickness ratio of the sealing layer, the intermediate layer, and the laminate layer is 1:3, and cooling and solidifying with a cooling roll at 30°C, corona discharges on the surface of the laminate layer of the obtained sheet. After the treatment, the roll was wound in a roll shape at a speed of 150 m/min to obtain a polyethylene resin film having a thickness of 50 µm and a wet tension on the surface of the laminate layer of 45 N/m.

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, and have stable blocking resistance and slipping properties, and also appearance and scratch resistance. The castle was also excellent. Moreover, the film forming processability was also excellent.

The polyethylene-based resin film obtained in Example 6 had a variation in the measured values between the measurement sample and the blocking resistance and the friction coefficient, but was suitable for medium weight and the like, and was excellent in appearance and scratch resistance. Moreover, the film forming processability was also excellent.

(Comparative Examples 1 to 5)

The resins and additives shown in Table 2 were used as raw materials for the sealing layer, the laminate layer, and the intermediate layer, and each was melted at 240°C using three extruders, filtered through a sintered filter having a filtration precision of 60 µm, and T After coextrusion from the die into a sheet, melt-extruding such that the thickness ratio of the sealing layer, the intermediate layer, and the laminate layer is 1:3, and cooling and solidifying with a cooling roll at 30°C, corona discharges on the surface of the laminate layer of the obtained sheet. After the treatment, the roll was wound in a roll shape at a speed of 150 m/min to obtain a polyethylene resin film having a thickness of 50 µm and a wet tension on the surface of the laminate layer of 45 N/m.

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

The film obtained in Comparative Example 2 was excellent in blocking resistance and slipperiness, but 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 great flicker feeling, and the appearance was remarkably inferior.

The film obtained in Comparative Example 4 had melt unevenness on the surface, there was also a flicker feeling, and the appearance was remarkably inferior. Moreover, the blocking resistance, slip resistance, and scratch resistance were also poor.

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

(Comparative Examples 6 and 7)

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

The polyethylene-based resin films obtained in Comparative Examples 6 and 7 had excellent heat-sealing properties, and the blocking resistance and friction coefficient were small due to fluctuations in measured values between measurement samples, and thus had stable blocking resistance and slipping properties. Moreover, it was excellent in scratch resistance and also excellent in film forming processability. However, the presence of an appearance gel was increased over time, which was inferior to Examples 1 to 6.

The results are shown in Table 1 and Table 2.

As described above, the method for manufacturing the polyethylene-based resin film of the present invention has been described based on a plurality of examples, but the present invention is not limited to the configurations described in the above examples, and the configurations described in the respective examples are appropriately combined. Etc., the structure can be appropriately changed without departing from the gist.

Industrial availability

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

Claims (3)

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