TW201922449A - Method for producing polyethylene resin film - Google Patents

Abstract

In order to efficiently and stably produce a polyethylene resin film having excellent heat sealability, and in addition, excellent appearance and scratch resistance, the present invention provides a method for producing a polyethylene resin film, the method comprising: a step for melt-kneading a polyethylene resin composition containing particles of a polyethylene resin, and a polyethylene resin; a step for melt-extruding the polyethylene resin composition to form a melted polyethylene resin composition sheet; and a step for cooling and solidifying the melted polyethylene resin composition sheet, wherein the step for melt-kneading the polyethylene resin composition includes a step for performing filtration using a filter having a filtration accuracy of 100 [mu]m or less.

Description

   Manufacturing method of polyethylene resin film   

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

In recent years, packaging or containers using a film have been used in a wide range of fields due to convenience, resource saving, reduction of load on the environment, and the like. Compared with conventional molded containers and molded products, the film has the advantages of light weight, easy disposal, and low cost.

For example, in general, a sealant film is a substrate film layer, such as a biaxially stretched nylon film, a biaxially stretched ester film, or a biaxially stretched polypropylene film, which is inferior to the sealant film in low-temperature heat adhesion. Laminate and use. If laminated with these substrate films and stored in a roll, there will be blocking between the sealant film and the substrate film, and it will not be easy to rewind the layer before bag-making processing. In the case of lamination, or the sealant films that become the inner surface of the bag during the bag-making process may adhere to each other and it is not easy to fill the food.

Therefore, it is known to prevent the adhesion of the sealant film and the substrate or the adhesion of the sealant film to each other by dusting starch or the like on the surface of the sealant film.

However, this countermeasure causes problems such as not only contaminating the periphery of the film processing apparatus, but also significantly deteriorating the appearance of the packaged food, or that powder adhered to the sealant film is directly mixed into the package together with the food, resulting in a decrease in heat seal strength.

Therefore, there is a report of a polyethylene-based resin film in which an inorganic fine powder such as silicon dioxide or an inorganic fine particle is used for the polyethylene-based resin (for example, refer to Patent Document 1).

However, this countermeasure also has the following problems: When the film surfaces containing inorganic fine powders or inorganic particles such as alumina or silicon dioxide added to the polyethylene-based film are rubbed against each other, scratches are easily generated, and the sealant When a laminated body of a film or a base film passes through a laminator, a bag making machine, or the like, the inorganic fine powder or inorganic particles easily fall off when they come into contact with a part of the machine (for example, refer to Patent Document 1).

Furthermore, there is reported a polyethylene-based resin film using organic cross-linked particles composed of a copolymer containing an acrylic monomer and a styrene-based monomer as main components (for example, refer to Patent Document 1).

However, in this countermeasure, although the susceptibility to damage is not as bad as that of inorganic particles, it is difficult to say enough. In addition, the problem of resistance to blocking or particle shedding still remains.

Furthermore, when the polyethylene raw resin composition is melt-kneaded and extruded to form a sheet, the polyethylene resin is decomposed and rebonded, and as a result, a cross-linked organic substance, which is called a gel, is generated. Therefore, a filter is used to generate the generated resin. The so-called gel filtration is indispensable for quality control. In this case, there is a problem that if the inorganic particles or the crosslinked organic particles agglomerate and block the mesh of the filter, the filter must be replaced, resulting in a decrease in operability or an increase in cost. In addition, there is a problem in that if the extrusion speed is given priority and a filter with low filtration accuracy is used, the so-called gel removal is insufficient, and gel defects increase with time and the quality decreases.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 10-86300.

An object of the present invention is to efficiently and stably produce a polyethylene-based resin film which is excellent in heat-sealability, appearance, and scratch resistance, and has few particles falling off.

The present inventors made intensive studies in view of the above-mentioned actual situation, and as a result, found that the above-mentioned problems can be solved by producing a polyethylene-based resin film using a particle made of a polyethylene-based resin and using a filter having high filtration accuracy, thereby Solve the invention.

That is, the present invention is a method for producing a polyethylene-based resin film, comprising: a step of melt-kneading a polyethylene resin composition containing particles made of a polyethylene-based resin and a polyethylene-based resin; A step of melt-extruding the material to produce a molten polyethylene resin composition sheet; and a step of cooling and solidifying the molten polyethylene resin composition sheet; the step of melt-kneading the polyethylene resin composition is included The filtration step is performed using a membrane having a filtration accuracy of 100 μm or less.

In this case, the viscosity average molecular weight of the particles made of the polyethylene resin is preferably 1.5 million or more, and the melting point peak temperature obtained by DSC (Differential Scanning Calorimetry) is 150 ° C or lower.

In this case, the filtration accuracy of the filter is preferably 80 μm or less.

According to the present invention, it is possible to efficiently and stably produce a polyethylene-based resin film having excellent heat-sealability and excellent appearance and scratch resistance.

(Particles made of polyethylene resin)

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

If it is the viscosity average molecular weight of this range, the maximum mountain height of the surface layer of at least one side of the obtained film can be made into 2 micrometers or more and 15 micrometers or less. The reason for this is not clear, but it is presumed that the molecules are not mixed with each other because the molecular weight difference between the particles made of polyethylene resin and the polyethylene resin other than the particles made of polyethylene resin is very large. In the film obtained by melt mixing and extrusion, it is easy to maintain the shape of the particles made of polyethylene resin, and it is not easy to cause the particles to fuse or adhere to each other, so it can be used on the film surface and inorganic The particles similarly form protrusions corresponding to the particle diameter.

If the viscosity average molecular weight of the particles made of polyethylene resin is less than 1.5 million, when the temperature during melt mixing is higher than the peak melting point, the particles will be decomposed or fused with heat or shear due to heat or shear, or the base resin will Partial compatibility results in changes in particle size and shape, so if the protrusions of the previous inorganic particles or organic crosslinked polymer beads cannot be formed, the function as an anti-blocking agent is not sufficient. Not only this, but also the appearance such as transparency 2, the film's mechanical strength or heat sealability.

In addition, if 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, but in this case, there is a tendency that it is difficult to form an appropriate film surface protrusion.

Furthermore, it is surprising that it has the following characteristics: Although particles made of a polyethylene resin having a viscosity average molecular weight of 1.5 million or more have a property of being difficult to agglomerate, it is more difficult than other inorganic particles to mix with other particles mixed with the particles The vinyl-based resin comes off.

In addition, if the viscosity average molecular weight of particles made of polyethylene-based resin is 1.5 million or more, the particles themselves have lubricity, which contributes to the improvement in blocking or sliding resistance. Moreover, the particles made of polyethylene-based resin have a viscosity Soft, so scratch resistance is also improved.

The average particle diameter of the particles made of a 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. The average particle diameter is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

Moreover, it is preferable not to contain the particle | grains whose particle diameter is 25 micrometers or more. Even if the average particle diameter is 20 μm or less, if 1% or more of the particles having a particle size of 25 μm or more are included, the maximum mountain height of the film surface is likely to exceed 15 μm, so if the film surface is visually observed, flicker described later will occur.

In addition, particles having a diameter of 25 μm or more are also not satisfactory in terms of being defective and deteriorating in quality.

(Polyethylene resin)

In the present invention, polyethylene resins other than the "particles made of polyethylene resin" refer to homopolymers of ethylene monomers, copolymers of ethylene monomers and α-olefins, and mixtures thereof as α-olefins. Examples 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. In order to obtain a polyethylene resin film having both heat sealability and blocking resistance, it is preferably 900 kg / m ³ to 940 kg / m ³ , more preferably 905 kg / m ³ to 935 kg / m ³ , still more preferably 910 kg / m ³ to 930 kg / m ³ , even more preferably 915 kg / m ³ to 925 kg / m ³ . Polyethylene resin with a density of less than 900 kg / m ³ is liable to decrease the blocking resistance.

Polyethylene resins with a density greater than 940kg / m ^{3 have a} high heat-seal starting temperature, difficult bag-making processing, and poor transparency. However, when polyethylene resins with a density greater than 940kg / m ^{3 are} used, it is necessary to reduce filtration. The present invention is very effective for producing a polyethylene-based resin film having excellent strength such as packaging weights or a film with few manufacturing defects, and the frequency of replacement of the device.

The anti-blocking property is a sample obtained by overlapping the measurement surfaces of the films on each other in a hot press (model: SA-303 manufactured by TESTER SANGYO), with a size of 7 cm × 7 cm, a temperature of 50 ° C., a pressure of 440 kgf / cm ² , and a time 15 minutes of pressure treatment. The sample and the stick (diameter 6mm, made of aluminum) that were stuck during this pressure treatment were mounted on an electronic universal testing machine (AUTOGRAPH) (made by Shimadzu Corporation, model UA-3122) so that the stick and the peeling surface became horizontal. Measure the force when the stick is peeled off at four speeds (100m / min) for four times, and take the average value of four times as an index, but when using a polyethylene resin with a density greater than 0.940g / m ³ , It was confirmed that not only the measured value of each of the four measurements is liable to change, but also the heat-seal starting temperature tends to be high. It is preferable that the variation of the measured value in each of the four measurements is at the same level as in the case of using the inorganic particles.

The reason why the measured value is easily changed in each measurement sample is not clear at present, but it is presumed that if a high-density polyethylene resin is used as the basis, the average viscosity of particles made of the polyethylene resin will be generated. As the molecular weight decreases or the particle diameter changes due to the intertwining of molecular chains with polyethylene resin other than the particles composed of polyethylene resin, the resulting protrusions on the surface become more uneven.

As the polyethylene-based resin other than the particles made of the polyethylene-based resin of the present invention, in terms of film forming properties, the melt flow rate (hereinafter sometimes referred to as MFR) is preferably 2.5 g / min. To about 10g / min. Here, MFR is measured in accordance with JIS (Japanese Industrial Standard) K7210. The polyethylene resin is synthesized by a method known per se.

In the case where a polyethylene resin other than particles made of a polyethylene resin in the present invention uses a resin having a lower MFR, such as 2.5 g / 10 min or less, the polyethylene resin is likely to cause the same as the description in the density. The viscosity average molecular weight of the particles made of the resin decreases or the particle diameter changes due to the intertwining with the molecular chains of the polyethylene resin other than the particles made of the polyethylene resin, so it is necessary to pay attention to the extrusion conditions. When a large-scale film forming machine is used for high-speed film formation, the MFR is particularly preferably about 3 g / 10 min to 4 g / 10 min in terms of film forming properties.

As the polyethylene resin other than the particles made of the polyethylene resin in the present invention, in terms of heat resistance, the melting point is preferably 85 ° C or higher, more preferably 100 ° C or higher, and even more 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, or two or more polyethylene-based resins having different densities in the above-mentioned density range may be blended. When two or more polyethylene resins with different densities are blended, the average density and blending ratio of the polyethylene resin can be estimated by GPC (Gel Permeation Chromatography) measurement or density measurement. .

As the polyethylene resin other than the particles made of polyethylene resin having a density of 900 kg / m ³ to 940 kg / m ³ as described above, the following polyethylene resins can be selected according to the application: transparent, flexible, and tearable High-pressure low-density polyethylene (LDPE: Low Density Polyethylene; low-density polyethylene) with excellent cracking strength and tensile strength on average; copolymerize a small amount of butene-1 / hexene-1octene-1 on the molecular chain A linear short-density branched polyethylene (LLDPE: Linear Low Density Polyethylene) with a large number of short molecular chains, excellent sealing performance and physical strength; shows a very steep molecular weight distribution, and the comonomer distribution is also uniform And metallocene catalyst linear short chain branched polyethylene (LLDPE: Linear Low Density Polyethylene; linear low density polyethylene) with excellent tearing, tensile, puncture strength and pinhole resistance.

The addition amount of the particles made of a polyethylene-based resin in the present invention is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and still more preferably 0.4% by weight or more with respect to the entire film. In addition, it is preferably 2% by weight or less, more preferably 1.5% by weight or less, and still more preferably 1.0% by weight or less. If the amount of particles made of polyethylene resin is less than 0.1% by weight, it will be difficult to set the maximum mountain height of at least one side of the obtained film to 2 μm or more per specified area (0.2 mm ² ). It is not easy to obtain anti-blocking or sliding properties. In addition, if the amount of particles made of a polyethylene-based resin is more than 2% by weight, the surface protrusions increase, the transparency is poor, and the low-temperature sealability is easily deteriorated.

In the polyethylene-based resin film of the present invention, known additives such as an antioxidant, a neutralizing agent, an organic lubricant, a non-dropping agent, and an antistatic agent may be used in combination as long as the objects and effects of the present invention are not impaired. 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 laminated film has improved lubricity or anti-blocking effect, and the operability of the film becomes good. The reason for this is considered to be that the organic lubricant oozed out and existed on the surface of the film, thereby exhibiting the lubricant effect or mold release effect. Furthermore, as the organic lubricant, it is preferable to add an organic lubricant having a melting point higher than normal temperature. Examples of the organic lubricant include fatty acid amidoamine and fatty acid ester. Specifically, it is oleyl oleate, erucyl eramine, melamine behenyl amine, melamine oleate, hexamethylene bisoleate, and the like. These can also be used alone, but by using two or more types in combination, it is possible to maintain the lubricity or anti-blocking effect even under severe environments, so it is preferable.

The lower limit of the concentration of the organic lubricant amine in the film of the present invention or the layer containing particles made of a polyethylene resin is preferably 200 ppm, more preferably 400 ppm. If the above-mentioned lower limit is not reached, sliding properties may deteriorate. The upper limit of the amine concentration of the organic lubricant is preferably 2500 ppm, and more preferably 2000 ppm. If the above upper limit is exceeded, the sliding is excessive and unfavorable.

In addition, an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, and the like can also be used in the range of not impairing the object and efficacy of the present invention.

The polyethylene-based resin film in the present invention must contain substantially no inorganic particles. When inorganic particles are substantially contained, not only is it difficult to obtain the effect of adding particles made of polyethylene resin such as scratch resistance or particles not falling off, but also when using a filter with high filtration accuracy, the filter is boosted. If it is fast, it will cause a decrease in operability due to the filter replacement. The inorganic particles referred to here refer to inorganic substances generally used as anti-blocking agents such as silicon dioxide, talc, calcium carbonate, diatomaceous earth, and zeolite, and the so-called “substantially free” refers to the entire polyethylene resin film of the present invention The ratio of the amount of the inorganic particles is 0.2% by weight or less. It is more preferably 0.1% by weight or less.

The polyethylene-based resin film in the present invention must contain substantially no crosslinked organic particles. When the crosslinked organic particles are substantially contained, the effect of adding particles made of a polyethylene resin, such as scratch resistance or particle shedding, is not easily obtained. The cross-linked organic particles herein refer to cross-linked particles typified by polymethyl acrylate resin and the like, and the term “substantially free” refers to a ratio of the amount of cross-linked organic particles in the entire polyethylene-based resin film of the present invention. It is 0.2% by weight or less. It is more preferably 0.1% by weight or less.

(Film forming method)

As a method for producing the polyethylene-based resin film of the present invention, for example, it is preferable to use a polyethylene-based resin composed of polyethylene-based resin and particles other than polyethylene-based resin A step of melt-kneading the material; a step of melt-extrusion of the melt-kneaded 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 laminated layer. In the case of lamination, another layer different from the layer containing particles made of polyethylene resin and having a maximum mountain height of at least one surface layer of 2 μm or more and 15 μm or less may 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, still more preferably 15 μm or more, and even more preferably 20 μm or more. The thickness is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. If it is less than 3 μm, the effect of particles made of a polyethylene resin is reduced, and it is difficult to exhibit the effect of blocking resistance or sliding properties.

In the case of lamination, the thickness of the layer containing particles made of polyethylene resin and having a maximum mountain height of at least one side of the surface layer is 2 μm or more and 15 μm or less, preferably 3 μm or more, more preferably 10 μm or more, It is preferably 15 μm or more, and particularly preferably 20 μm or more. The thickness is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. If it is less than 3 μm, the effect of particles made of polyethylene resin is reduced, and the effect of blocking resistance or sliding properties is not exhibited.

(Raw material mixing step)

When mixing particles made of polyethylene resin with polyethylene resin other than particles made of polyethylene resin, any method may be used to uniformly mix these particles. When using a master batch, Examples include a method of mixing using a belt mixer, a Henschel mixer, a tumbler mixer, and the like. In the case of direct addition, particles made of a polyethylene resin can be attached to the resin with an adhering agent, or they can be directly added to the extruder using a side feed or the like.

A small amount of a masterbatch prepared by mixing a particle made of a polyethylene resin with a polyethylene resin other than the particles made of a polyethylene resin at a high concentration, and a polyethylene resin other than the particles made of a polyethylene resin The dispersibility of the resin mixed method is also good and simple. However, it can be obtained when a particle made of a polyethylene resin is directly mixed with a linear low-density polyethylene, a homopolymer of an ethylene monomer, and a copolymer of an ethylene monomer and an α-olefin without using a master batch. Because of its high dispersibility, direct addition using a side feed method or the like is preferred in terms of cost.

(Melt kneading step)

First, drying or hot air drying is performed so that the moisture content of the polyethylene-based resin other than the particles made of the polyethylene-based resin and the particles made of the polyethylene-based resin may be less than 1000 ppm. Then, each raw material is measured and mixed, and it is 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 the lower limit is not reached, the ejection may become unstable. The upper limit of the melting temperature of the resin composition is preferably 260 ° C. If it exceeds the above-mentioned upper limit, the resin composition is decomposed and rebonded, and as a result, the amount of foreign matter such as a so-called gel, which is a cross-linked organic substance generated, increases.

When the above-mentioned antioxidant is contained in the polyethylene-based resin composition, melt extrusion can be performed at a higher temperature, but it is preferably set to 270 ° C or lower.

The melting point of the particles made of polyethylene resin used in the present invention is about 150 ° C or lower, and it is mixed with polyethylene resins other than the particles made of polyethylene resin. Although the temperature is far lower than the temperature during melt-kneading, Surprisingly, the particles made of polyethylene resin are not dispersed at molecular level in polyethylene resins other than "particles made of polyethylene resin", but are extruded from a T-die and passed through In the polyethylene-based resin film obtained in the cooling step, the particles made of the polyethylene-based resin remain unchanged in particle size and shape before being added to the polyethylene-based resin other than the particles made of the polyethylene-based resin.

(Filter)

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 material used in high-precision filtration of molten resin is not particularly limited. In the case of a filter material of a stainless steel sintered body, in addition to so-called gels and other foreign materials, Si, Ti, and Sb derived from additives such as catalysts are used. Removal performance of the agglomerates of Ge, Cu, and Cu as main components is also excellent and preferable. The filtration accuracy is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 70 μm or less.

The particles made of polyethylene resin in the present invention have the following advantages: because they are melted during melt-kneading, they can be filtered not only with high-precision filter materials, but also because they have fewer coarse particles, so they are clogged than inorganic particles. The resulting boost is less. Furthermore, there is an advantage that, by reducing the average particle diameter or narrowing the particle size distribution of particles made of a polyethylene resin, even if it is produced industrially with a high-precision filter material having a filtration accuracy of 60 μm or less, there is less clogging. , Can remove foreign matter, and there is no damage to the blocking resistance caused by particles made of polyethylene resin.

The filtering accuracy referred to here is a nominal filtering accuracy, and has a performance of capturing particles with a size of 60% or more (for example, particles with a filtering accuracy of 60 μm or more when the filtering accuracy is set to 60 μm). Absolute filtering accuracy is the performance of catching more than 99.9% of particles with a display filtering accuracy or more, but even the nominal filtering accuracy is preferably close to the absolute filtering accuracy in terms of performance.

(Filter boost)

The amount of pressure increase during melt-kneading the polyethylene-based resin composition is preferably small. The method of measuring the amount of pressure increase is performed by the method described in the examples.

(Melt extrusion step)

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

The particles made of polyethylene resin used in the present invention are originally hydrophobic resins. Therefore, even after the steps of melt-kneading and extrusion, the surface of the particles does not change in hydrophobicity, and it is extremely difficult for the surface to undergo hydrophobic treatment. In the inorganic particles, the thermal degradation at the lip of the T-die is also known as the accumulation of so-called orifice resin deposits.

Examples include a method of forming a resin composition obtained by melt-extruding a molten polyethylene-based resin composition sheet by a T-die method or an inflation method, but the melting temperature of the resin composition can be increased. In this respect, a T-mode method is particularly desirable.

(Die Lip Contamination)

When the polyethylene resin composition is melt-extruded from the T-die, the contamination of the die lip of the T-die is preferably less. The measurement method of the lip contamination was performed by the method described in an Example.

(Cooling and solidifying step)

For example, it is preferred that the molten sheet of a polyethylene-based resin composition melt-extruded from a T-die is cast on a cooling roll and cooled. The lower limit of the cooling roll temperature is preferably 10 ° C. If the above-mentioned lower limit is not reached, 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 upper limit, the degree of crystallinity may become too high and the appearance may be deteriorated. When the temperature of the cooling roller is in the above range, in order to prevent dew condensation, it is preferable to reduce the humidity of the environment near the cooling roller in advance.

During casting, the temperature of the surface of the cooling roller rises because the high-temperature resin contacts the surface. Generally, the cooling roller is cooled by circulating cooling water through a pipe inside, but the temperature difference in the width direction of the surface of the cooling roller must be reduced, for example, to ensure a sufficient amount of cooling water, study the arrangement of the pipe, and perform maintenance so that the sediment does not adhere. For piping, etc. At this time, the thickness of the unstretched sheet is preferably in a range of 3 μm to 200 μm.

(Multilayer structure)

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

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

For example, the following methods can be used: using a feeder table, a static mixer, a multi-manifold die, etc., the thermoplastic resin sent from two or more extruders from different flow paths is laminated into multiple layers. In addition, it is also possible to use only one extruder to introduce the above-mentioned multilayering device to a melt line from the extruder to a T-die.

In the case of a three-layer structure, it is preferable to have a structure that sequentially includes the following layers: a layer containing particles made of a polyethylene resin and having a maximum mountain height of at least one side of a surface layer of 3 μm or more and 15 μm or less As the sealing layer (layer A), the other layers were respectively set as an intermediate layer (layer B) and a laminated layer (layer C). The outermost layers are layer A and layer C, respectively.

Examples of the polyethylene resin used as the intermediate layer (layer B) and the laminated layer (layer C) include, for example, one type selected from the group consisting of an ethylene / α-olefin copolymer and a high-pressure polyethylene, and two or more types mixed with each other. Into the resin. The ethylene / α-olefin copolymer is a copolymer of ethylene and an α-olefin having 4 to 18 carbon atoms. Examples of the α-olefin include butene-1, hexene-1, 4-methylpentene-1, and octane. Ene-1, decene-1 and the like.

Films obtained from these polyethylene-based resins have excellent heat-sealing strength, hot-tack properties, inclusion sealing properties, and impact resistance. The polyethylene-based resins can also be mixed within the range that does not impede these characteristics, such as ethylene-vinyl acetate. Other resins, such as an ester copolymer and an ethylene-acrylate copolymer, are used.

At this time, the polyethylene resin used in the intermediate layer (layer B) and the laminated layer (layer C) may be the same or different. In addition, particles made of a polyethylene resin may or may not be added. However, it does not substantially contain inorganic particles and organic crosslinked particles. The term "substantially free" 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% by weight or less. It is more preferably 0.1% by weight or less.

In this case, the average density of the polyethylene-based resin in each layer of the film is preferably a sealant layer (layer A) ≦ intermediate layer (layer B) ≦ laminated layer (layer C). Since the formulated organic lubricant does not easily move to a layer having a high density, it is effective for maintaining the sliding property after lamination.

At this time, the lower limit of the density of the intermediate layer (layer B) and the laminated layer (layer C) is preferably 900 kg / m ³ , more preferably 920 kg / m ³ , and even more preferably 930 kg / m ³ . If the above-mentioned lower limit is not reached, the toughness may be weak and processing may not be easy.

The upper limit of the density of the intermediate layer (layer B) and the laminated 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 can be used in the intermediate layer (layer B) 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 the above-mentioned lower limit is not reached, sliding properties may deteriorate.

The upper limit of the erucamide concentration in the intermediate layer (layer B) is preferably 2000 ppm, and more preferably 1500 ppm. If the upper limit is exceeded, there may be a case where the winding is shifted due to excessive sliding.

The intermediate layer (layer B) of the polyethylene-based resin film in the present invention may be blended with 10% to 30% by weight of the recycled resin.

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

In the case of two layers, it is preferable to use a layer containing polyethylene-based resin and a layer having a maximum mountain height of at least one side of 3 μm or more and 15 μm or less as the sealing layer (layer A), and the other layers Let it be a laminated layer (C layer).

(Maximum protrusion height)

The maximum mountain height of the surface layer of 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. In the case where the maximum mountain height Rz exceeds 15 μm, appearance defects occur, which is not satisfactory. The measurement method was performed by the method described in an Example.

(Number of protrusions above 15 μm)

In the polyethylene-based resin film of the present invention, the number of protrusions (pieces / 0.2 mm ² ) in the surface layer having a maximum mountain height of 2 μm to 15 μm on the surface is preferably 0 or less. The smaller the number, the worse the appearance such as flickering feeling and haze. The measurement method was performed by the method described in an Example.

(Heat seal starting temperature)

The upper limit of the heat-seal initiation temperature of the polyethylene-based resin film obtained by laminating the biaxially stretched nylon film (15 μm) is preferably 130 ° C., and more preferably 120 ° C. If the above upper limit is exceeded, it may be difficult to perform sealing processing. The measurement method was performed by the method described in an Example.

(Extreme heat seal strength)

The lower limit of the ultimate heat-sealing strength of a polyethylene resin film obtained by laminating a biaxially stretched nylon film (15 μm) at 120 ° C. is preferably 30 N / 15 mm, and more preferably 35 N / 15 mm. If the lower limit is not reached, the bag may be easily broken after the bag is made.

The upper limit of the ultimate heat-sealing strength of a polyethylene resin film obtained by laminating a biaxially stretched nylon film (15 μm) at 120 ° C. is preferably 70 N / 15 mm, and more preferably 65 N / 15 mm. If the above upper limit is exceeded, the bag may not be easily opened after the bag is made. The measurement method was performed by the method described in an Example.

(Adhesion strength)

The lower limit of the adhesion strength of the polyethylene resin film obtained by laminating a biaxially stretched nylon film (15 μm) is preferably 0 mN / 20 mm, more preferably 10 mN / 20 mm, and even more preferably 15 mN / 20 mm.

The upper limit of the adhesion strength is preferably 150 mN / 20 mm, more preferably 50 mN / 20 mm, and even more preferably 40 mN / 20 mm. If the upper limit is exceeded, the sliding property may be deteriorated immediately after being rolled out. The measurement method was performed by the method described in an Example.

(Friction strength)

The lower limit of the static friction coefficient after lamination of a polyethylene resin film obtained by laminating a biaxially stretched nylon film (15 μm) is preferably 0.05, more preferably 0.08. If the above-mentioned lower limit is not reached, there is a case where the film is excessively slipped during winding and the winding may be shifted.

The upper limit of the static friction coefficient after lamination is preferably 0.50, more preferably 0.4. If it exceeds the above upper limit, the opening property after bag making may be poor, and the loss during processing may increase.

The measurement method was performed by the method described in an Example.

(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 the above-mentioned lower limit is not reached, there may be a small amount of anti-adhesive agent, which may cause adhesion.

The upper limit of the haze is preferably 15%, more preferably 12%, and still more preferably 10%. If the upper limit is exceeded, the content may not be easily recognized. The measurement method was performed by the method described in an Example.

(Flickering)

It is preferable that the polyethylene-based resin film of the present invention has almost no flicker, or even though there is fine flicker, it is uniform without special attention. The measurement method was performed by the method described in an Example.

In the conventional so-called non-powder type, which has blocking resistance even if powder such as starch is not sprinkled on the film surface, conventionally, there is a polyethylene resin added with inorganic particles having an average particle diameter of about 10 μm. Film, but there are cases where flicker is poor.

(Scratch resistance)

It is preferable that the polyethylene resin film formed by laminating a biaxially stretched nylon film (15 μm) is hardly scratched after being pinched and wiped with a finger so that the sealing surfaces of the film overlap each other 10 times Although small streak-like scars were produced, they did not turn white. The measurement method was performed by the method described in an Example.

In the conventional so-called powder-free type, which has blocking resistance even if powder such as starch is not sprinkled on the surface of the film, although conventionally, there is a polyethylene-based resin film added with inorganic particles having an average particle size of about 10 μm, but it is scratch-resistant. Poor sex.

(Young's modulus)

The lower limit of the Young's modulus (MD (Machine Direction)) of the polyethylene-based resin film of the present invention is preferably 100 MPa, and more preferably 200 MPa. If the above lower limit is not reached, the toughness may be too weak to be easily processed. The upper limit of the Young's modulus (MD) is preferably 800 MPa, and more preferably 600 MPa.

The lower limit of the Young's modulus (TD (Transverse Direction)) of the polyethylene film of the present invention is preferably 100 MPa, more preferably 200 MPa. If the above lower limit is not reached, the toughness may be too weak to be easily processed.

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

[Example]

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not particularly limited by the following examples. The measured values of each item in the detailed description of the present invention and the examples are measured by the following methods.

Hereinafter, embodiments of the present invention will be described in detail.

(I) Method for measuring particles made of polyethylene resin

The physical properties of the raw resin before processing were measured on particles made of a polyethylene resin.

In addition, even after the film is formed, the particles made of polyethylene resin can be separated and measured by the following method: using decane as a solvent, polyethylene other than the particles made of polyethylene resin can be used. Dissolve the membrane at the temperature of complete dissolution, filter the residue with a filter with a filtration accuracy of 2 μm, or completely melt the particles in decane, and then separate the high molecular weight part by GPC or the like.

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

Measured according to ASTM (American Society for Testing Materials)-D4020.

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

The average particle diameter of the particles made of polyethylene resin before use was measured in the following manner.

The particles were dispersed in ion-exchanged water stirred at a predetermined rotation speed (about 5000 rpm) using a high-speed stirrer, and the dispersion was added to Isoton (trade name) (physiological saline). The coulter counter method calculates a particle size distribution and calculates a volume average particle diameter.

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

The ratio of particles having a particle diameter of 25 μm or more in the particles made of polyethylene resin before use is calculated from the particle size distribution obtained by the Coulter counting 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 size of 10 mg and a temperature increase rate of 10 ° C / min. Here, the detected melting endothermic peak temperature is taken as the melting point.

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

The raw materials before film formation were measured by the following methods, respectively.

In addition, for a polyethylene resin other than the particles composed of a polyethylene resin, which forms a layer including particles made of a polyethylene resin, the entire layer is confirmed with an electron microscope or the like when the layer is a single layer, and the electron microscope is used when the layer is laminated. After confirming the composition of the layer, the surface is shaved to the thickness of the surface layer, and the resin can be measured in the same manner by removing the solvent from the filtered solution obtained in the above (1). In the case of cutting from a self-laminating layer, it can be carried out relatively easily by laminating it on a polyethylene terephthalate (PET) film or the like and then cutting it with a razor or the like.

(Density)

Measured by the density gradient tube method in accordance with JIS-K7112.

(Melting Flow Rate: MFR) (g / 10min)

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

(Melting point)

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

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

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

In addition, even after the film is formed, the inorganic particles can be separated and measured by the following method: using decane as a solvent, the film can be dissolved at a temperature at which polyethylene other than the particles made of polyethylene resin can be completely dissolved. Dissolve and filter the residue with a filter with a filter accuracy of 2 μm.

(8) Filter boost (film forming processability)

Based on the amount of pressure increase (△ MPa) in the following cases as the reference (△), they are classified into the following ◎, ○, △, and ×: Using a Troughton tester, a sintered metal cloth filter with a filtration accuracy of 60 μm The filtration area was 81 pi square millimeters, and the resin composition used in the sealing layer was discharged at a resin temperature of 230 ° C. for 5 hours at a discharge amount of 1 kg / hour.

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

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

Δ: The amount of boost is the same as that of Comparative Example 1.

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

(9) Die lip contamination (film forming processability)

The contamination of the die lip when the resin composition used in the sealing layer was extruded at 230 ° C. for 5 hours by using a wire die in an extruder was visually observed. (△), classified into the following ◎, ○, △, ×.

：: Hardly any stain on the lip was confirmed.

○: Slight lip contamination is seen.

(Triangle | delta): The lip stain | contamination was recognized clearly.

×: The mold lip is contaminated and grows, and a stripe-like depression is generated in the strand.

(10) Maximum protrusion height

The three-dimensional surface roughness SRa is a contact surface roughness (model ET4000A manufactured by Kosaka Research Institute). The maximum surface roughness of the measurement surface of 1 mm × 0.2 mm is determined from a 3 cm × 3 cm square film. Mountain height Rz. Rz measured in the above method was measured at n = 3 and the average value was determined.

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

The number of protrusions of 15 μm or more is based on the contact surface roughness (model ET4000A manufactured by Kosaka Research Institute), and the surface roughness of the sealing layer at a measurement surface of 1 mm × 0.2 mm is randomly measured from a 3 cm × 3 cm square film. It is determined by marking a protrusion having a maximum mountain height Rz of 15 μm or more. The count corresponds to the number of protrusions with an Rz of 15 μm or more, and is calculated from the average of the measured values of n = 3.

(12) Heat sealing start temperature (℃)

A dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to a nylon film (a biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) so that the solid content became 3 g / m ² . For the corona surface, the solvent was evaporated and removed in an oven at 80 ° C, and then the corona surface of the polyethylene resin film and the application surface of the adhesive were laminated on a temperature-adjusting roller at 60 ° C. The laminated laminated film was aged at 40 ° C for 2 days. The prepared laminated samples were heat-sealed with a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, a sealing temperature of 90 ° C. to 160 ° C. and a pitch of 10 ° C. with a width of 10 mm.

The heat-sealed sample was cut into short strips so that the heat-sealing width became 15 mm, and placed on an electronic universal testing machine (manufactured by Shimadzu Corporation; model number UA-3122). The sealing surface was peeled off at a speed of 200 mm / min, and n The maximum value of the peel strength was measured, and the heat seal strength and the heat seal temperature at each temperature were plotted. A graph obtained by connecting the graphs in a straight line is read as a heat-sealing temperature of 4.9 N / 15 mm, and is set as a heat-sealing starting temperature.

(13) Ultimate heat seal strength (N / 15mm)

A dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to a nylon film (a biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) so that the solid content became 3 g / m ² . For the corona surface, the solvent was evaporated and removed in an oven at 80 ° C, and then the corona surface of the polyethylene resin film and the application surface of the adhesive were laminated on a temperature-adjusting roller at 60 ° C. The laminated film was aged at 40 ° C for 2 days. The prepared laminated samples were heat-sealed with a sealing pressure of 0.1 MPa, a sealing time of 0.5 seconds, a sealing temperature of 120 ° C. to 190 ° C. and a pitch of 10 ° C. with a width of 10 mm.

The heat-sealed sample was cut into short strips so that the heat-sealing width became 15 mm, and placed on an electronic universal testing machine (manufactured by Shimadzu Corporation; model number UA-3122). The sealing surface was peeled off at a speed of 200 mm / min, and n The maximum value of the peel strength was measured, and the heat seal strength with the highest average value was defined as the ultimate seal strength.

(14) Adhesive strength

A laminated film with a nylon film (a biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) was produced in the following manner.

The dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to the corona surface of the nylon film so that the solid content became 3 g / m ² , and the solvent was evaporated and removed in an oven at 80 ° C. , The corona surface of the polyethylene-based resin film and the application surface of the adhesive were laminated on a temperature-adjusting roller at 60 ° C. The laminated film was aged at 40 ° C for 2 days.

A sample (10cm × 15cm) formed by overlapping measurement surfaces with each other so that the end of an aluminum plate (2mm thickness) having a size of 7cm × 7cm is aligned with the center of the sample width (10cm) and 1cm inside the length direction (15cm). The system was placed in a hot press (manufactured by TESTER SANGYO; model: SA-303), and subjected to a pressure treatment at a temperature of 50 ° C, a pressure of 440 kgf / cm ² for a period of 15 minutes.

The sample and rod (diameter 6mm; aluminum) that were stuck during the pressure treatment were mounted on an electronic universal testing machine (manufactured by Shimadzu Corporation; model: UA-3122), and the stick was peeled off at a speed (100m / min). Force.

In this case, the level of the rod and the peeling surface is assumed. Four measurements were performed on the same sample, and the average value was shown.

(15) Static friction coefficient

A laminated film with a nylon film (a biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) was produced in the following manner.

The dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to the corona surface of the nylon film so that the solid content became 3 g / m ² , and the solvent was evaporated and removed in an oven at 80 ° C. The corona surface of the polyethylene resin film and the application surface of the adhesive were laminated on a temperature-adjusting roller at 60 ° C. The laminated film was aged at 40 ° C for 2 days. According to JIS-K7125, the static friction coefficients of the polyethylene resin film surfaces of the produced laminated film were measured under an environment of 23 ° C and 65% RH.

(16) Haze

The direct reading haze meter manufactured by Toyo Seiki Seisakusho Co., Ltd. was used to measure only the polyethylene resin film in accordance with JIS-K7105.

Haze (%) = [Td (diffusive transmittance%) / Tt (full light transmittance%)] × 100

(17) Flicker

Only the polyethylene-based resin film was visually observed, and the flickering feeling was classified into the following ◎, ○, △, and ×.

：: Hardly any bright spots were felt.

○: Although there are small bright spots, they are uniform without paying special attention.

(Triangle | delta): There is a bright spot locally and a foreign body feeling is sensed.

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

(18) Over time appearance

After replacing the filter with a filtration accuracy of 60 μm over the entire layer, film formation was started. Using the film formation method described in the examples, the polyethylene resin film was visually observed at a size of A4 and n = 3 for 7 days. The number of foreign matters in ² was classified into the following ◎, ○, △, and ×.

(Double-circle): The gel-like foreign material of 0.2 mm (phi) or more and 1 mm or less did not reach 1/1000 cm <^2> .

(Circle): The number of gel foreign bodies of 0.2 mm (phi) or more and 1 mm or less does not reach 2 pieces / 1000 cm <^2> .

Δ: The number of gel foreign bodies from 0.2 mm φ to 1 mm is 2 or more and less than 4 per 1000 cm ² .

X: The number of gel foreign bodies of 0.2 mmφ or more and 1 mm or less is 4 per 1000 cm ² or more.

(19) Scratch resistance

A laminated film with a nylon film (a biaxially stretched nylon film manufactured by Toyobo: N1100, 15 μm) was produced in the following manner.

The dry laminating adhesive (TM569, CAT-10L) manufactured by Toyo-Morton was applied to the corona surface of the nylon film so that the solid content became 3 g / m ² , and the solvent was evaporated and removed in an oven at 80 ° C. , The corona surface of the polyethylene-based resin film and the application surface of the adhesive were laminated on a temperature-adjusting roller at 60 ° C. The laminated film was aged at 40 ° C for 2 days. The polyethylene resin film surfaces of the produced laminated film were rubbed 10 times with a finger so as to overlap with each other, and visually observed to classify damage easiness into the following ◎, ○, △, ×.

：: Hardly any scars.

(Circle): A thin stripe-like scar was produced, but did not turn white.

(Triangle | delta): A thin stripe-like dense scar is seen, and it becomes white locally.

×: Most of the rubbed area turned white.

Next, the present invention will be described in more detail using examples and comparative examples, but the present invention is not limited to the following examples.

In Examples and Comparative Examples, the following materials were used.

(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-based 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-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., with a density of 923 kg / m ³ , MFR 3.8 g / 10 min, and a melting point of 118 ° C.).

(4) FV407 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., with a density of 930 kg / m ³ , MFR 3.2 g / 10 min, and a melting point of 124 ° C.).

(5) 3540F (metallocene-based 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-based 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 Co., Ltd., density 969 kg / m ³ , MFR 14 g / 10 min, heat distortion temperature (4.6 Kg / cm ² ) 80 ° C.).

(Particles made of polyethylene resin)

(1) MIPELON XM220 (Ultra-high molecular weight polyethylene particles, manufactured by Mitsui Chemicals Co., Ltd., density 940kg / m ³ , melting point 136 ° C, viscosity average molecular weight 2 million, Shore hardness 65D, volume average particle size 30μm, more than 30μm The particle size is 55% by weight).

(2) Improved MIPELON PM220 (ultra-high molecular weight polyethylene particles, manufactured by Mitsui Chemicals Co., Ltd., density 940kg / m ³ , melting point 135 ° C, viscosity average molecular weight 1.8 million, Shore hardness 65D, volume average particle size 10μm, The weight ratio of the particle diameter exceeding 25 μm is 1% or less).

(Inorganic particles)

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

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

(Organic lubricant)

(1) Ethyl bisoleate (manufactured by Sumitomo Chemical, 2% Ethyl bisoleate masterbatch EMB11).

(2) Erucic acid erucamide (manufactured by Sumitomo Chemical, using erucic acid erucamide 4% masterbatch EMB10).

(Examples 1 to 6)

The resins and additives shown in Table 1 were used as raw materials for the sealing layer, the laminated layer, and the intermediate layer. Each of the three extruders was used to melt them at 240 ° C, and filtered using a sintered filter with a filtration accuracy of 60 μm. , Co-extruded from the T-die into a sheet, melt-extruded so that the thickness ratio of the sealing layer, the intermediate layer, and the laminated layer becomes 1: 3: 1, and after cooling and solidification using a cooling roller at 30 ° C, After the corona discharge treatment was performed on the surface of the laminate layer of the obtained sheet, it was wound into a roll shape at a speed of 150 m / min to obtain a polyethylene system having a thickness of 50 μm and a wetting tension of 45 N / m on the surface of the laminate layer. Resin film.

The polyethylene-based resin films obtained in Examples 1 to 5 are excellent in heat-sealability, have small variations in blocking resistance and friction coefficient between measured values, and have stable blocking resistance and sliding properties. It also has excellent appearance and scratch resistance. In addition, the film forming processability is also excellent.

Although the blocking resistance and friction coefficient of the polyethylene-based resin film obtained in Example 6 were changed between the measurement samples, they were suitable for heavy bags and the like, and had excellent appearance and scratch resistance. In addition, the film forming processability is also excellent.

(Comparative Example 1 to Comparative Example 5)

The resins and additives shown in Table 2 were used as raw materials for the sealing layer, the laminated layer, and the intermediate layer. Each of the three extruders was used to melt at 240 ° C, and then filtered using a sintered filter with a filtration accuracy of 60 μm. , Co-extruded from the T-die into a sheet, melt-extruded so that the thickness ratio of the sealing layer, the intermediate layer, and the laminated layer becomes 1: 3: 1, and after cooling and solidification using a cooling roller at 30 ° C, After the corona discharge treatment was performed on the surface of the laminate layer of the obtained sheet, it was wound into a roll shape at a speed of 150 m / min to obtain a polyethylene system having a thickness of 50 μm and a wetting tension of 45 N / m on the surface of the laminate layer. Resin film.

Although the film obtained in Comparative Example 1 was excellent in blocking resistance and sliding properties, it not only had a slight flickering feeling and poor scratch resistance, but also had a significant increase in filter pressure and poor film forming processability.

Although the film obtained in Comparative Example 2 was excellent in blocking resistance and sliding properties, it had a flickering feeling and was inferior in appearance.

Although the film obtained in Comparative Example 3 was excellent in blocking resistance and transparency, the flickering feeling was severe and the appearance was very poor.

The film obtained in Comparative Example 4 had uneven melting on the surface, also had a flickering feeling, and the appearance was very poor. In addition, blocking resistance, sliding properties, and scratch resistance were also poor.

Although the film obtained in Comparative Example 5 was excellent in blocking resistance, it had a flickering feeling and was inferior in appearance. In addition, it has poor scratch resistance and film-forming processability.

(Comparative Example 6 and Comparative Example 7)

The resins and additives shown in Table 2 were used as raw materials for the sealing layer, the laminated layer, and the intermediate layer. Each of the three extruders was used for melting at 240 ° C, and the sintered filters with a filtration accuracy of 200 μm and 120 μm were used. After filtering, it is co-extruded into a sheet form from the T-die, melt-extruded so that the thickness ratio of the sealing layer, the intermediate layer, and the laminated layer becomes 1: 3: 1, and is cooled and solidified by a cooling roller at 30 ° C. After the corona discharge treatment was performed on the surface of the laminate layer of the obtained sheet, it was wound into a roll shape at a speed of 150 m / min to obtain a polymer having a thickness of 50 μm and a wetting tension on the surface of the laminate layer of 45 N / m. Vinyl resin film.

The polyethylene resin films obtained in Comparative Examples 6 and 7 were excellent in heat-sealability, had small changes in blocking resistance and friction coefficient between measured values, and had stable blocking resistance and sliding properties. In addition, it is also excellent in scratch resistance and film forming processability. However, the appearance of the gel-like substance increased over time and was inferior to those of Examples 1 to 6.

The results are shown in Tables 1 and 2.

The manufacturing method of the polyethylene-based resin film of the present invention has been described based on a plurality of embodiments, but the present invention is not limited to the structures described in the above-mentioned embodiments, and the structures described in the respective embodiments may be appropriately combined. The configuration of the present invention may be changed as appropriate without departing from the gist of the present invention.

(Industrial availability)

The method for producing a polyethylene-based resin film according to the present invention can efficiently and stably produce a polyethylene-based resin film having excellent characteristics, and therefore, it can be suitably used as a film for a wide range of applications such as food packaging.

Claims (3)

    A method for producing a polyethylene-based resin film, comprising: a step 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 The step of preparing a molten polyethylene resin composition sheet; the step of cooling and solidifying the molten polyethylene resin composition sheet; the step of melt-kneading the polyethylene resin composition includes using a filtration accuracy of 100 μm or less Filter step.         The method for producing a polyethylene-based resin film according to claim 1, wherein 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 obtained by a differential scanning calorimeter 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.