TW201922871A - Polyethylene resin film - Google Patents

Abstract

Provided is a polyethylene resin film which has excellent heat sealability, blocking resistance, and slipperiness, and also has excellent appearance and scratch resistance. This polyethylene resin film is characterized by comprising a polyethylene resin composition that contains particles of a polyethylene resin, and a polyethylene resin having a density of 940 kg/m3 or less, but substantially does not contain inorganic particles or organic crosslinked particles, wherein the maximum peak height of at least one surface thereof is 2-15 [mu]m.

Description

   Polyethylene resin film   

The present invention relates to a polyethylene resin film. More specifically, the present invention relates to a polyethylene-based resin film which is excellent in heat sealability, stable blocking resistance, and stable sliding properties, and also has excellent appearance and scratch resistance.

In recent years, packaging or containers using a film have been used in a wide range of fields based on convenience, resource saving, reduction in 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.

Generally speaking, a sealant film is generally used by laminating a substrate film 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. . If laminated with these substrate films and stored in a roll shape, adhesion between the sealant film and the substrate film may occur, and it is difficult to rewind the laminated film before bag-making processing, or There is a case where the sealant films that become the inner surface of the bag during the bag-making process adhere to each other, making it difficult to fill the food.

Therefore, it is known to prevent the adhesion of the sealant film and the base material or the adhesion of the sealant film to each other by spraying 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 device, but also significantly deteriorating the appearance of the packaged food, or that the powder adhered to the sealant film is directly mixed into the package with the food, resulting in a decrease in heat seal strength.

Therefore, there is a report of a polyethylene-based film in which inorganic fine powder or inorganic fine particles such as silicon dioxide is used for the polyethylene-based resin.

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 with each other, scratches are likely to occur. When a laminated body of a film, a sealant 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 degree of vulnerability 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.

Further, a polyethylene resin film in which a high-density polyethylene resin is added to a linear low-density polyethylene resin in order to improve the blocking resistance of the polyethylene resin film has been reported (for example, refer to Patent Document 2).

However, these countermeasures have problems such as mechanical strength characteristics such as tensile strength or deterioration in transparency, and also have poor blocking resistance.

In addition, a polyethylene-based resin inflation film suitable for a shopping bag has been reported, and particles made of a polyethylene resin having a very high molecular weight are added to a high-density polyethylene resin (for example, refer to Patent Document 3).

However, this countermeasure has the following problems: excessive tear strength, or poor heat-sealing properties and transparency at low temperatures, and the addition of particles made of polyethylene resin makes the sliding properties unstable.

[Prior technical literature]

[Patent Literature]

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

Patent Document 2: Japanese Patent Laid-Open No. 10-87909.

Patent Document 3: Japanese Patent Laid-Open No. 2008-88248.

An object of the present invention is to provide a polyethylene-based resin film which is excellent in heat-sealability, stable blocking resistance, stable sliding properties, appearance, and scratch resistance, and has less particle detachment. Another object of the present invention is to provide a laminated body and further a packaging body using the polyethylene-based resin film.

The present inventors conducted diligent research in view of the above-mentioned actual situation, and as a result, found that the polyethylene resin film having a density of a specific range or less contained particles made of a polyethylene resin to control the protrusions on the surface of the film. Highly, the above problems can be solved, thereby solving the present invention.

That is, the present invention is a polyethylene-based resin film, which is composed of a polyethylene-based resin composition and has a maximum peak height of at least one side of a surface of 2 μm or more and 15 μm or less. The polyethylene-based resin composition contains The particles made of a polyethylene-based resin and the polyethylene resin having a density of 940 kg / m ³ or less are substantially free of inorganic particles and organic crosslinked particles.

In another aspect, a polyethylene resin film is characterized in that it has a layer made of a polyethylene resin composition on at least one side, and the maximum peak height of the surface of the layer is 2 μm or more and 15 μm or less. The polyethylene-based resin composition contains particles made of a polyethylene-based resin, contains substantially no inorganic particles and organic crosslinked particles, and has a density of 940 kg / m ³ 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.

Moreover, in this case, it is preferable to include erucamide and / or acetaminophen.

Furthermore, in this case, it is preferable that the adhesion value between the surface layers having the maximum peak height of 2 μm or more and 15 μm or less is 200 mN / 70 mm or less.

Preferably, it is a laminated body which consists of a polyethylene resin film and other films as described in any one of the above.

Preferably, it is a packaging bag containing the laminated body as described above.

The present invention can provide a polyethylene-based resin film which is excellent in heat-sealability, stable blocking resistance, and stable sliding properties, and is also excellent in appearance and scratch resistance. In addition, a laminated body using the polyethylene-based resin film, and a packaging body can be provided.

(Polyethylene resin film)

The polyethylene-based resin film of the present invention is composed of a polyethylene-based resin composition, and mainly contains a polyethylene-based resin. The polyethylene resin refers to a homopolymer of an ethylene monomer, a copolymer of an ethylene monomer and an α-olefin, and a mixture thereof. Examples of the α-olefin include propylene, butene-1, and hexene. -1, 4-methylpentene-1, octene-1, decene-1 and the like.

The density range of the polyethylene resin composition in the present invention is preferably 900 kg / m ³ to 940 kg / m ³ , more preferably 910 kg / m ³ to 940 kg / m ³ , and still more preferably 910 kg / m ³ to 935 kg / m ³ , particularly preferably 915 kg / m ³ to 935 kg / m ³ , and particularly preferably 915 kg / m ³ to 925 kg / m ³ . The polyethylene resin composition having a density of less than 900 kg / m ³ is liable to decrease the blocking resistance.

The polyethylene resin composition having a density of more than 940 kg / m ³ has a high heat-seal initiation temperature, is difficult to make bags, and has poor transparency. Furthermore, it is important that the present inventors discovered that when a polyethylene-based resin composition having a density of more than 940 kg / m ³ is used, it is difficult to obtain stable blocking resistance or stable sliding properties of the polyethylene-based resin film. .

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 rod (diameter: 6mm diameter: aluminum) that were adhered during the pressure treatment were mounted on an electronic universal testing machine (AUTOGRAPH) (Shimadzu Corporation model: UA-3122) so that the rod and the peeling surface became horizontal. The force when the stick was peeled off at a speed of 100 m / min was measured four times, and the average value of the four times was taken as an index. However, when using a polyethylene resin composition having a density of more than 940 kg / m ³ , it was confirmed Not only the measured values in each of the four measurements are prone 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.

As the polyethylene-based resin composition in the present invention, the melt flow rate (hereinafter sometimes referred to as MFR; Melt mass-flow rate) is preferably 2.5 g / min to 4.5 g / around min.

Here, MFR is measured according to ASTM D1893-67. The polyethylene resin is synthesized by a method known per se.

When the polyethylene resin composition in the present invention uses a resin composition having a lower MFR, such as 2.5 g / 10 min or less, it is confirmed that not only the blocking resistance is easily changed, but also the heat, as in the description of the density. Since the seal initiation temperature tends to be high, attention must be paid 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-based resin composition 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 even more preferably 110 ° C or higher.

The polyethylene-based resin composition in the present invention may be a single system, or two or more polyethylene 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. . Furthermore, particles made of a polyethylene resin described below can be blended.

(Particles made of polyethylene resin)

In the present invention, it is preferable to use particles made of polyethylene resin. In this case, the viscosity average molecular weight of particles made of polyethylene resin is preferably 1.5 million or more, more preferably 1.6 million or more, and more More than 1.7 million. 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.

When the viscosity average molecular weight is within this range, the maximum peak height of the surface layer on at least one side can be 2 μm or more and 15 μm or less. The reason for this is not clear, but it is presumed that the molecular weight of the polyethylene resin other than the particles made of the polyethylene resin is very large, so the molecules are not mixed with each other. In the film obtained by melt-mixing and extruding, it is easy to maintain the shape of particles made of polyethylene resin, and it is also difficult to cause the particles made of polyethylene resin to fuse or adhere to each other. Like the inorganic particles, protrusions corresponding to the particle diameter can be formed on the surface of the film.

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 they will be mixed with the base resin. 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-adhesive agent is not sufficient. Not only this, but also transparency and so on The appearance, the mechanical strength of the film, or the heat-sealability are affected.

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, that is, 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, they are more difficult to mix with the aforementioned particles than inorganic particles. Other polyethylene resins came 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.

In the present invention, the particles made of a polyethylene resin are homopolymers of ethylene monomers, or copolymers of ethylene monomers and α-olefins, and mixtures thereof. Examples of the α-olefins include propylene and butene. -1, hexene-1, 4-methylpentene-1, octene-1, decene-1 and the like.

The density of the particles made of polyethylene resin in the present invention is preferably from 930 kg / m ³ to 950 kg / m ³ , more preferably from 935 kg / m ³ to 945 kg / m ³ , and even more preferably from 937 kg / m ³ to 942kg / m ³ . The particles made of polyethylene resin with a density of less than 930 kg / m ^{3 are} soft, and it is difficult to maintain the shape of the particles during melt extrusion, and the blocking resistance is easily reduced. In addition, the particles made of polyethylene resin having a density of more than 950 kg / m ^{3 are} hard and have a low scratch resistance. Moreover, the affinity with the base polyethylene resin is reduced, so the drop resistance is easily reduced.

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.

In addition, 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, if 1% or more of the particles having a particle diameter of 25 μm or more are included, the maximum peak height of the film surface is likely to exceed 15 μm. In this way, if the film surface is visually observed, flicker described later will occur.

In addition, particles having a diameter of 25 μm or more are not as good as defects because they cause a reduction in quality.

The addition amount of the particles made of a polyethylene resin according to 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 based on 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 addition amount of the particles made of polyethylene resin is less than 0.1% by weight, it is difficult to set the maximum peak height of at least one side of the surface layer to 2 μm or more in a unit specified area (0.2 mm ² ), and it is difficult to obtain anti-adhesion. Connected or sliding. 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.

(Polyethylene resin)

In the present invention, polyethylene resins other than the so-called "particles made of polyethylene resin" refer to homopolymers of ethylene monomers, or copolymers of ethylene monomers and α-olefins, and mixtures of these. Examples of the α-olefin include propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, and decene-1.

The density range of the polyethylene resin other than the particles made of the polyethylene resin in the present invention is preferably 900 kg / m ³ to 940 kg / m ³ , more preferably 910 kg / m ³ to 940 kg / m ³ , and even more preferably to 920kg / m ³ to 940kg / m ^3, particularly preferably 920kg / m ³ to 935kg / m ^3, in particular, more preferably 920kg / m ³ to 925kg / 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 of more than 940 kg / m ^{3 have a} high heat-seal starting temperature, make bag making difficult, and have poor transparency. More importantly, the present inventors have found that when a polyethylene resin having a density of more than 940 kg / m ³ is used, it is difficult to obtain stable blocking resistance or stable sliding properties of the polyethylene resin film.

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 rod (diameter: 6 mm in diameter: aluminum) that were adhered during the pressure treatment were mounted on an electronic universal testing machine (model: UA-3122 manufactured by Shimadzu Corporation) so that the rod and the peeling surface became horizontal, and the rod was measured 4 times. The force at the time of peeling the adhesive part at a speed (100 m / min) will be an average value of 4 times as an index. However, when using a polyethylene resin with a density of more than 940 kg / m ³ , it is confirmed that the force is not less than 4 times. The measured value of each measurement is liable to change, and 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 easy to change in each measurement sample is not clear at present, but it is presumed that if it is mixed with a polyethylene resin with a high density, an average viscosity of the particles made of the polyethylene resin will be generated. As the molecular weight decreases or the particle diameter changes due to intertwining with molecular chains of polyethylene resin other than the particles made of polyethylene resin, the resulting protrusions on the surface become more uneven.

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 Density Polyethylene (LDPE; Low Density Polyethylene) with excellent cracking and tensile strengths on average; small amounts of butene-1 / hexene-1 octene-1 copolymerized, and a large number of short molecular chains in the molecular chain , Linear short-chain branched polyethylene (LLDPE; Linear Low Density Polyethylene) with excellent sealing performance and physical strength; showing very steep molecular weight distribution, comonomer distribution is uniform, and tearing , Metallocene catalyst, linear short-chain branched polyethylene (LLDPE) with excellent tensile, puncture strength, and pinhole resistance.

As the polyethylene-based resin other than the particles made of the polyethylene-based resin in the present invention, the melt flow rate (hereinafter, sometimes referred to as MFR) is preferably 2.5 g / min to 4.5 in terms of film forming properties and the like. g / min. Here, MFR is measured in accordance with JIS-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 having different densities are blended, the average density and blending ratio of the polyethylene resin can be estimated by GPC measurement or density measurement.

In the polyethylene 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.

In the present invention, an organic lubricant is preferably added. The laminated film has improved lubricity or anti-blocking effect, and the film has good operability. The reason for this is considered to be because the organic lubricant oozes out and exists on the surface of the film, and exhibits a lubricant effect or a 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, fluorenyl oleate, erucyl erucate, fluorenyl pivalate, fluorenyl dioleate, hexamethylene bisoleate, and the like. These can also be used alone, but by using two or more kinds in combination, it is convenient for harsh environments and can maintain the lubricity or anti-blocking effect, so it is preferable.

The lower limit of the concentration of the organic lubricant amine in the layer containing particles made of a polyethylene-based 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 mixed and used as long as the objects and effects of the present invention are not impaired.

The polyethylene-based resin film of the present invention must be substantially free of inorganic particles. When the inorganic 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 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. The so-called substantially free particles mean the polyethylene resin film of the present invention. The ratio of the amount of the inorganic particles in the whole is 0.2% by weight or less. It is more preferably 0.1% by weight or less.

The polyethylene resin film of the present invention must be substantially free of 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. The term “substantially free” means the amount of cross-linked organic particles in the entire polyethylene-based resin film of the present invention. The ratio 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 (before A step of melt-kneading a polyethylene resin composition made of a polyethylene resin that has been used); a step of melt-kneading the resin composition that has been melt-kneaded to form a molten resin composition sheet And a step of cooling and solidifying the molten resin composition sheet.

The polyethylene-based resin film of 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 peak height of at least one side of the 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-based resin decreases, and it is difficult to exhibit the effects of blocking resistance and sliding properties.

In the case of lamination, the thickness of a layer containing particles made of polyethylene resin and having a maximum peak 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 a polyethylene-based resin decreases, and it is difficult to exhibit the effects of blocking resistance and sliding properties.

(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, Henschel mixer, drum mixer, and the like. In the case of direct addition, particles made of a polyethylene-based resin can be attached to the resin with an additive, or it can be directly added to the extruder using a side feed or the like.

A small amount of a masterbatch made 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, 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, Since high dispersibility is obtained, 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 as a film material. 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 is preferably 200 ° C, more preferably 210 ° C, and still more preferably 220 ° C. If the lower limit is not reached, the ejection may become unstable. The upper limit of the resin melting temperature is preferably 260 ° C. When the above-mentioned upper limit is exceeded, the resin is decomposed and rebonded, and as a result, the amount of cross-linked organic matter, ie, foreign matter such as a so-called gel, 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-based resin are not dispersed at molecular level in polyethylene-based resins other than the particles made of polyethylene-based resin, but are extruded from a T-die and cooled. In the polyethylene-based resin film obtained in the step, the particles made of the polyethylene-based resin exist without changing the particle size and shape before adding 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 200 μm or less.

The term "filtration accuracy" as used herein has the following meaning.

The filtering precision is a nominal filtering precision, and has a performance of capturing particles with a size greater than or equal to the filtering precision of 60% to 98% (here, 200 μm or more).

(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, a 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 achieving 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 thermally-degraded matter on the lip of the T-die, that is, the accumulation of so-called orifice resin deposits can be seen.

Examples thereof 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. However, the melting temperature of the resin composition can be increased. In other words, T mode is particularly preferred.

(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-mentioned upper limit, crystallization proceeds and the transparency becomes poor, which is not preferable. When the temperature of the cooling roller is in the above range, it is preferable to reduce the humidity of the environment near the cooling roller in advance in order to prevent condensation.

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 pipes inside, but the temperature difference in the width direction of the surface of the cooling roller must be reduced. Attach to 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 of the present invention may have a multilayer structure. In the case of multiple layers, in addition to the layer composed of the polyethylene-based resin composition described above and having a maximum peak height on the surface of 2 μm or more and 15 μm or less, one or more other layers may be provided.

As a specific method for performing the multilayering in this manner, a general multilayering apparatus (multilayer feeder table, static mixer, multilayer multi-manifold die, etc.) can be used.

For example, the following methods can be used: using a feeder table or 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 including the following layers in order: a layer composed of a polyethylene resin composition and having a maximum peak height on the surface of 3 μm or more and 15 μm or less is used as a sealing layer (layer A ), And set the other layers 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, and 4-methylpentene-1. , Octene-1, decene-1, etc.

The films obtained from these polyethylene-based resins have excellent heat-sealing strength, hot-tack properties, inclusion sealability, and impact resistance. The polyethylene-based resins can also be mixed with other resins such as An ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, and the like 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, it is preferable that the average density of the polyethylene resin in each layer of the film is a sealant layer (layer A) ≦ intermediate layer (layer B) ≦ laminated layer (layer C). The formulated organic lubricant does not easily move to a layer with a high density, and is therefore effective for the sliding property of the laminated sealant layer.

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 film of the present invention. 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 film of the present invention may also be formulated with 10% to 30% by mass 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 lamination strength.

In the case of two layers, it is preferable to use a layer containing a polyethylene resin and having a maximum peak height of at least one side of the surface layer of 2 μm or more and 15 μm or less as the sealing layer (layer A). The layer was a laminated layer (C layer).

(Maximum protrusion height)

The maximum peak 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 peak height Rz exceeds 15 μm, appearance defects occur, which is not preferable. 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 ) exceeding 15 μm in the surface layer having a maximum peak height of 2 μm or more and 15 μm or less 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 resin film obtained by laminating the biaxially stretched nylon film (15 μm) is preferably 130 ° C., and more preferably 120 ° C. m. If the above upper limit is exceeded, it may be difficult to perform sealing processing.

(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 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.

(Coefficient of friction)

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 past, the so-called Non-Powder Type, which has blocking resistance even if powder such as starch is not sprinkled on the surface of the film, has previously been a polyethylene resin film with inorganic particles having an average particle size of about 10 μm. , But the 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 past, the so-called powder-free type, which is resistant to blocking even if powder such as starch is not sprinkled on the surface of the film, has previously been a polyethylene resin film with inorganic particles having an average particle size of about 10 μm, but has poor scratch resistance .

(Young's modulus)

The lower limit of the Young's modulus (MD (Machine Direction)) of the polyethylene resin 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 (MD) is preferably 800 MPa, and more preferably 600 MPa.

The lower limit of the Young's modulus (TD (Transverse Direction)) of the polyethylene-based resin 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 the items 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.

(1) 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, that is, using decane as a solvent in addition to particles made of polyethylene resin Polyethylene completely dissolves at a temperature in the lower limit region to dissolve the membrane, filter the residue with a filter with a filtration accuracy of 2 μm, or completely melt the particles in decane, and then use GPC to separate the high molecular weight part, etc. .

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

Measured in accordance with ASTM-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 (physiological saline). The dispersion was further dispersed by an ultrasonic disperser and counted by Coulter The particle size distribution was calculated to calculate the volume average particle size.

(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. That is, using decane as a solvent can completely dissolve polyethylene other than the particles made of polyethylene resin. The membrane was dissolved at a temperature, and the residue was filtered with a filter having a filtration accuracy of 2 μm.

(8) Filter boost (film forming processability)

Based on the resin composition used in the sealing layer, at a resin temperature of 230 ° C., using a Troughton tester, the filter area of a metal fiber sintered filter with a filtration accuracy of 120 μm was 81 pi square millimeters at 1 kg. The amount of pressure increase (ΔMPa) when the ejection amount per hour was discharged for 5 hours was used as a reference (Δ), and was classified into the following ◎, ○, △, and ×, respectively.

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

：: The amount of pressure increase is 95% 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 by a strand die at 230 ° C. for 5 hours in an extruder was visually observed. Lip stains were used as a reference (Δ) and classified into the following ◎, ○, △, and ×.

：: 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 uses a contact-type surface roughness (model ET4000A manufactured by Kosaka Research Institute). The surface roughness of a measurement surface of 1 mm × 0.2 mm is arbitrarily measured from a 3 cm × 3 cm square film to determine the maximum value. Peak 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 arbitrarily measured from a 3 cm × 3 cm square film. A peak having a maximum peak height Rz of 15 μm or more was obtained by marking. 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 (Shimadzu Corporation model: UA-3122). The sealing surface was peeled at a speed of 200 mm / min, and the number was n. 3 Measure the maximum value of the peel strength, and plot the heat seal strength and heat seal temperature at each temperature. 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 (Shimadzu Corporation model: UA-3122). The sealing surface was peeled at a speed of 200 mm / min, and the number was n. 3 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 (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 15 minutes.

The sample and the stick (diameter: 6mm diameter: aluminum) that were adhered during the pressure treatment were mounted on an electronic universal testing machine (Shimadzu Corporation model: UA-3122), and when the stick was peeled off at a speed (100 m / min), the stick was measured. Of 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) 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 fingers so as to overlap with each other, and visually observed to classify the degree of damage 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 raw materials were used.

(Polyethylene resin)

(1) 0540F (metallocene-based linear low-density polyethylene, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 904kg / m ³ , MFR4.0g / 10min, melting point 111 ° C)

(2) FV402 (metallocene-based linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density: 913kg / m ³ , MFR3.8g / 10min, melting point: 115 ° C)

(3) FV405 (metallocene linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density 923kg / m ³ , MFR3.8g / 10min, melting point 118 ° C)

(4) FV407 (metallocene linear low-density polyethylene, manufactured by Sumitomo Chemical Co., Ltd., density: 930kg / m ³ , MFR3.2g / 10min, melting point: 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 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 969kg / m ³ , MFR14g / 10min, heat distortion temperature (4.6Kg / 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 (Weight ratio of particle size 55%)

(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, (Weight ratio of particle diameters exceeding 25 μm is less than 1%)

(Inorganic particles)

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

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

(Organic lubricant)

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

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

(Examples 1 to 5)

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 for melting at 240 ° C, and a sintered filter with a filtration accuracy of 120 μm was 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-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.

(Comparative Example 1 to Comparative Example 6)

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 a sintered filter with a filtration accuracy of 120 μm was 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.

Although the film obtained in Comparative Example 1 was excellent in blocking resistance and sliding properties, it had a slight flickering feeling and was inferior in scratch resistance and 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. The film obtained in Comparative Example 3 was excellent in blocking resistance and transparency, but had a flickering feeling and very poor appearance. 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. The blocking resistance and the coefficient of friction of the film obtained in Comparative Example 5 had large fluctuations in the measured values between the measurement samples and were unstable. The reason is presumably because the particle diameter of the particles made of polyethylene resin is unstable and changes. Although the film obtained in Comparative Example 6 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. The results are shown in Tables 1 and 2.

The polyethylene 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 embodiments, and the structures described in each embodiment may be combined as appropriate. The configuration of the present invention is appropriately changed without departing from the scope of the gist of the present invention.

(Industrial availability)

The polyethylene-based resin film described in the present invention is excellent in characteristics, and therefore can be suitably used as a film for a wide range of applications such as food packaging.

Claims (7)

A polyethylene-based resin film is composed of a polyethylene-based resin composition and has a maximum peak height of at least one side of a surface of 2 μm or more and 15 μm or less. The polyethylene-based resin composition contains particles made of a polyethylene-based resin. And polyethylene resin having a density of 940 kg / m ³ or less, which substantially does not contain inorganic particles and organic crosslinked particles. A polyethylene-based resin film having a layer made of a polyethylene-based resin composition on at least one side, and a maximum peak height of the surface of the layer is 2 μm or more and 15 μm or less. The polyethylene-based resin composition contains a polymer The particles made of vinyl resin and polyethylene resin do not substantially contain inorganic particles and organic crosslinked particles, and have a density of 940 kg / m ³ or less.     The polyethylene resin film according to claim 1 or 2, wherein the particles made of the polyethylene resin have a viscosity average molecular weight of 1.5 million or more, and a melting point peak temperature obtained by a differential scanning calorimeter is 150 ° C or lower.         The polyethylene-based resin film according to any one of claims 1 to 3, which comprises erucamide and / or osmamine dioleate.         The polyethylene-based resin film according to any one of claims 1 to 4, wherein the adhesion value between the surface layers having a maximum peak height of 2 µm or more and 15 µm or less is 200 mN / 70 mm or less.         A laminated body comprising the polyethylene-based resin film according to any one of claims 1 to 5 and other films.         A packaging bag comprising the laminated body according to claim 6.