film

Abstract

In one embodiment of the present invention, in a film in which polypropylene is dispersed in polyethylene, deterioration of quality due to polypropylene can be suppressed. In a film according to one embodiment of the present invention, a dispersed phase is dispersed in a matrix phase. The film includes a matrix phase containing polyethylene and a dispersed phase containing polypropylene. The dispersed phase includes a flat phase oriented at least in the MD direction, and the average aspect ratio of the flat phase is 15 or more.

Description

[Technical field]

[0001] The present invention relates to a film comprising polyethylene. [Background technology]

[0002] There is a known technology for recycling polyethylene film (see, for example, Patent Document 1). In the technology described in Patent Document 1, a special washing process is provided to thoroughly wash away mud and other substances adhering to used polyethylene film that has been used in fields, etc., so that the film can be recycled as new polyethylene film.

[0003] There is also known a technology for recycling waste resin films whose main component is a resin other than polyethylene as one component of polyethylene film (see, for example, Patent Document 2). With this technology, the amount of virgin polyethylene material used in the production of polyethylene film can be reduced by the amount of waste resin films used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-052532 A [Patent Document 2] JP 2004-182957 A Summary of the Invention

[0005] In a film according to one embodiment of the present invention, a dispersed phase is dispersed in a matrix phase. The film comprises a matrix phase comprising polyethylene and a dispersed phase comprising polypropylene. The dispersed phase contains a flat phase oriented at least in the MD direction, and the average aspect ratio of the flat phase is 15 or more.

[0006] In one embodiment of the present invention, a method for producing a film having a dispersed phase dispersed in a matrix phase includes kneading a first raw material, which is made of polyethylene and constitutes the matrix phase, with a second raw material, which contains polypropylene as a component constituting the dispersed phase, and forming the mixture into a film. A ratio ηB / ηA of a viscosity ηB of polypropylene contained in the second raw material at a molding temperature to a viscosity ηA of the first raw material at the molding temperature during film molding is 0.015 or more and less than 1. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a partial cross section of a film according to one embodiment of the present invention. [Diagram 2] 4 is a flowchart showing a method for producing the film. [Diagram 3] 1 is a TEM image of a cross section of a kneaded product obtained in a kneading process. [Figure 4] This is a TEM image of the MD cross section of a film obtained in the film forming process. [Diagram 5] This is a TEM image of the TD cross section of the film obtained in the film molding process. [Figure 6] 1 is a TEM image of an MD cross section of a film according to a comparative example. [Figure 7] 1 is a TEM image of an MD cross section of a film according to Example 4. [Figure 8] 1 is a TEM image of the MD cross section of the film of Example 24. Detailed Description of the Invention

[0008] Since many absorbent articles such as diapers and sanitary napkins are made of resin, recycling waste absorbent articles is of great significance. However, when polypropylene, which is contained in large amounts in absorbent articles, is used as one component of polyethylene film, the quality of the polyethylene film is easily impaired in terms of strength, elongation, smoothness to the touch, etc.

[0009] The present invention relates to suppressing deterioration in quality caused by polypropylene in a film in which polypropylene is dispersed in polyethylene.

[0010] A film according to one embodiment of the present invention and a method for producing the same will be described.

[0011] [Film composition] The film according to the present embodiment has a matrix phase and a dispersed phase, and has a configuration in which the dispersed phase is dispersed in the matrix phase. The matrix phase contains polyethylene. The dispersed phase has a flat phase containing polypropylene.

[0012] In FIG. 1, the left-right direction of the paper corresponds to the MD direction (machine direction: flow direction of resin molding) of the film, the depth direction of the paper corresponds to the TD direction (transverse direction: direction perpendicular to MD) of the film, and the up-down direction of the paper corresponds to the thickness direction of the film. Each flat phase of the film according to this embodiment has a flat shape with an aspect ratio of 5 or more, is oriented at least in the MD direction in the in-plane direction, and is preferably oriented in the TD direction as well. In addition, the average aspect ratio of the flat layer, which is defined as the average value of the aspect ratios in the flat phase of the film according to this embodiment, is 15 or more, and preferably 20 or more. Furthermore, the average aspect ratio of the flat phase of the film according to this embodiment is preferably 100 or less, more preferably 50 or less, from the viewpoint of maintaining good low-temperature heat sealability. Each flat phase preferably extends in all directions in the in-plane direction, but may be formed into a band-like or needle-like shape extending only in the MD direction.

[0013] Moreover, the film according to the present embodiment preferably contains, as a dispersed phase, a spherical phase composed of a resin and having an aspect ratio of 3 or less. The spherical phase contributes to improving the tear strength of the film. The spherical phase may contain, for example, at least one of polyethylene terephthalate and polyurethane. In the film according to the present embodiment, the content of the resin constituting the spherical phase is preferably 0.05% by mass or more and 20% by mass or less. In the film according to the present embodiment, the average particle size of the spherical phase is preferably 1 nm or more and 2 μm or less.

[0014] The aspect ratio of each dispersed phase is measured using a TEM image taken using a transmission electron microscope (TEM). The film to be observed is processed into ultrathin slices using an ultramicrotome, and stained with a heavy metal (ruthenium tetroxide), which allows observation of the state of the matrix phase and dispersed phase. The observation surface of the film sample is the MD cross section formed by cutting in a direction parallel to the MD direction. The observation magnification is set to 2500 times or more, and a rectangular field of view with an in-plane dimension of 14.3 μm or more and a thickness dimension of 14.3 μm or more is obtained. The transmission electron microscope used is HT7820 (manufactured by Hitachi High-Tech Corporation), and the acceleration voltage is set to 100 kV. In this embodiment, the TEM image of the film sample can be used to measure not only the aspect ratio of each dispersed phase, but also the cross-sectional area of ​​each dispersed phase. This makes it possible to evaluate the content of the dispersed phase in the film and the ratio of the flat phase and the spherical phase in the dispersed phase by the cross-sectional area ratio.

[0015] The aspect ratio and cross-sectional area of ​​each dispersed phase observed in the TEM image of the film sample are measured using image analysis software Image-Pro10 (Media Cybernetics). The TEM image is imported and scaled using the "quick space construction function", and the dispersed phase (object) and matrix phase (background) are randomly surrounded in 10 places using the "smart (learning function)" to learn and extract all dispersed phases. After that, the "radius ratio" and "cross-sectional area" are measured with the "fill in the gap" option selected for target extraction. This radius ratio is treated as the aspect ratio of the dispersed phase for each dispersed phase. In this embodiment, among the dispersed phases, those with an aspect ratio of 5 or more are considered to be flat phases, and those with an aspect ratio of 3 or less are considered to be spherical phases. From the measurement results, dispersed phases with a radius ratio of 5 or more are extracted, the average value of the radius ratios of the extracted dispersed phases is considered to be the average aspect ratio of the flat phases, and the total value of the cross-sectional areas of the dispersed phases with a radius ratio of 5 or more is considered to be the total cross-sectional area of ​​the flat phases. In addition, the dispersed phase having a radius ratio of 3 or less is extracted from the measurement results, the average value of the radius ratios of the extracted dispersed phases is defined as the average aspect ratio of the spherical phase, and the total value of the cross-sectional areas of the dispersed phases having a radius ratio of 3 or less is defined as the total cross-sectional area of ​​the spherical phase. The total value of the cross-sectional areas of all dispersed phases included in the measurement results is defined as the total cross-sectional area of ​​the dispersed phase. The visual field area of ​​the TEM image is defined as the total cross-sectional area of ​​the film. By using these, various cross-sectional area ratios for the film can be obtained. For example, the ratio of the total cross-sectional area of ​​the dispersed phase to the total cross-sectional area of ​​the film, the ratio of the total cross-sectional area of ​​the flat phase to the total cross-sectional area of ​​the dispersed phase, and the ratio of the total cross-sectional area of ​​the spherical phase to the total cross-sectional area of ​​the dispersed phase can be obtained.

[0016] In the film according to the present embodiment, the matrix phase is continuous in the thickness direction because all the flat phases are interrupted in the in-plane direction. In other words, the structure in which the flat phase is dispersed in the matrix phase in the film according to the present embodiment is different from a laminate structure in which the matrix phase and the flat phase are alternately laminated in the thickness direction as a series of layers in the in-plane direction.

[0017] In this embodiment, since the dimensions of each flat phase in the thickness of the film in each MD cross section are small, the physical properties of each flat phase are unlikely to affect the physical properties of the film as a whole. In addition, in the film according to this embodiment, the thin flat phase is widely present in the in-plane direction, and the polypropylene constituting the flat phase is widely dispersed in the in-plane direction, so that the influence of polypropylene is not localized, and uniform physical properties are easily obtained along the in-plane direction. Furthermore, in the film according to this embodiment, since polypropylene is present as a flat phase, the impact of polypropylene on the touch is unlikely to be felt, and the smooth touch inherent to polyethylene is easily obtained.

[0018] Therefore, in the film according to this embodiment, the physical properties of the polyethylene constituting the matrix phase are dominant, regardless of the physical properties of the polypropylene constituting the flat phase. In other words, in the film according to this embodiment, regardless of the presence of polypropylene, it is easy to obtain high strength, high elongation, and smooth touch that are comparable to those of a film composed only of polyethylene. In the film according to this embodiment, it is preferable that the proportion of the flat phase in the entire dispersed phase is large. From this viewpoint, in the film according to this embodiment, the ratio of the total cross-sectional area of ​​the flat phase to the total cross-sectional area of ​​the dispersed phase in the TEM image is preferably 60% or more. In addition, in the film according to this embodiment, it is preferable that the ratio of the total cross-sectional area of ​​the spherical phase to the total cross-sectional area of ​​the film in the TEM image is 0.05% or more and 20% or less.

[0019] Therefore, the film according to the present embodiment can recycle waste containing polypropylene derived from various articles as one component thereof, and thus the amount of virgin polyethylene used can be reduced, thereby reducing the environmental impact associated with the production of the film according to the present embodiment.

[0020] Examples of waste containing polypropylene include waste derived from absorbent articles such as sanitary napkins, baby diapers, adult diapers, etc. Examples of waste derived from absorbent articles include used absorbent articles, absorbent articles determined to be defective before shipping, and scraps generated during the manufacturing process of absorbent articles.

[0021] Examples of waste containing polypropylene that can be recovered from absorbent articles include resin fibers and resin films. The technology according to the present embodiment expands the possibility of recycling in that even waste containing mixed resin fibers and resin films can be reused as a resin film with high strength and elongation and a smooth feel. In addition, since the resin contained in absorbent articles often has a higher melting point than polyethylene, it is easier to obtain high heat resistance by blending waste derived from absorbent articles, and the effect can be expected as the aspect ratio of the flat phase is increased.

[0022] In the film according to the present embodiment, the lower the polyethylene content and the higher the polypropylene content, the more difficult it is to obtain high strength, high elongation, and smooth touch. From this viewpoint, in the film according to the present embodiment, the ratio of the cross-sectional area of ​​polyethylene to the total cross-sectional area of ​​the film in a TEM image obtained by photographing the film with a transmission electron microscope is preferably 50% or more, more preferably 80% or more. The cross-sectional area of ​​polyethylene in the TEM image can be obtained as the cross-sectional area of ​​the matrix phase obtained by subtracting the total cross-sectional area of ​​the dispersed phase from the total cross-sectional area of ​​the film, assuming that the area occupied by polyethylene and the area occupied by the matrix phase coincide with each other. In the film according to the present embodiment, the ratio of the cross-sectional area of ​​polypropylene to the total cross-sectional area of ​​the film in a TEM image obtained by photographing the film with a transmission electron microscope is preferably 50% or less, more preferably 20% or less. The cross-sectional area of ​​polypropylene in the TEM image can be obtained as the cross-sectional area of ​​the flat phase, assuming that the area occupied by polypropylene and the area occupied by the flat phase coincide with each other. Furthermore, in the film according to the present embodiment, the polyethylene content is preferably 50% by mass or more, more preferably 80% by mass or more, and the polypropylene content is preferably 50% by mass or less, more preferably 20% by mass or less.

[0023] In addition, in the film according to the present embodiment, it is preferable to reduce the amount of virgin polyethylene used within a range where sufficient quality can be ensured depending on the application. From this viewpoint, in the film according to the present embodiment, the ratio of the cross-sectional area of ​​polyethylene to the total cross-sectional area of ​​the film in a TEM image of the film taken by a transmission electron microscope is preferably 99% or less, more preferably 80% or less. In addition, in the film according to the present embodiment, the ratio of the cross-sectional area of ​​polypropylene to the total cross-sectional area of ​​the film in a TEM image of the film taken by a transmission electron microscope is preferably 1% or more, more preferably 20% or more. Furthermore, in the film according to the present embodiment, the content of polyethylene is preferably 99% by mass or less, more preferably 80% by mass or less. In addition, in the film according to the present embodiment, the content of polypropylene is preferably 1% by mass or more, more preferably 20% by mass or more.

[0024] The film according to the present embodiment may contain a flat phase mainly composed of a component other than polypropylene as a dispersed phase. Furthermore, the film according to the present embodiment may contain a phase other than the flat phase and the spherical phase as a dispersed phase. This allows the film according to the present embodiment to improve its quality by using a dispersed phase other than the flat phase and the spherical phase. In the present embodiment, the term "main component" refers to a component whose content is 50% or more.

[0025] For example, the film according to the present embodiment preferably contains at least one of a styrene-based elastomer, an ethylene-α-olefin copolymer (including those in which ethylene exists as a comonomer), an olefin-based resin with a polar group introduced therein, and a styrene-based resin with a polar group introduced therein. These components have the effect of aiding dispersion and enhancing the performance of the resin, and therefore contribute to improving the tensile elongation, tensile strength, and tear strength of the film. In the film according to the present embodiment, the content of the resin constituting this phase is preferably 0.5% by mass or more and 15% by mass or less. Methods for introducing polar groups include graft polymerization in which monomers are bonded in a grafted manner using an electron beam, using a monomer containing a polar group during polymer synthesis, plasma treatment, corona treatment, and the like.

[0026] In addition, the film according to the present embodiment preferably contains an inorganic material phase composed of an inorganic material as the dispersed phase. Examples of inorganic materials constituting the inorganic material phase include calcium carbonate and titanium oxide, and calcium carbonate and titanium oxide contribute to improving tear strength and suppressing transmission of ultraviolet rays. In the film according to the present embodiment, the content of the inorganic material is preferably 0% by mass or more and 60% by mass or less from the viewpoint of molding stability. In addition, in the film according to the present embodiment, when determining the content (mass percentage, ratio of cross-sectional area in TEM image) of the resin component constituting the matrix phase and dispersed phase in a configuration containing an inorganic material phase, the presence of the inorganic material phase (mass, cross-sectional area in TEM image) is excluded from the calculation.

[0027] In the film according to the present embodiment, from the viewpoint of reducing the manufacturing cost, it is preferable that the materials constituting the phase other than the flat phase in the dispersed phase are as much as possible supplied from components contained in the waste together with polypropylene, however, in the film according to the present embodiment, any of these materials may be added separately from polypropylene.

[0028] The use of the film according to the present embodiment is not particularly limited. As an example, the film according to the present embodiment can be used as a package film for various products. Examples of products suitable for use as a package film in the film according to the present embodiment include sanitary products, baby diapers, adult diapers, and daily necessities.

[0029] The film according to the present embodiment preferably has desirable properties as a packaging film. For example, in order to obtain high durability as a packaging film, the film according to the present embodiment preferably has high tensile elongation, tensile strength, and tear strength. Specifically, the film according to the present embodiment preferably has a tensile elongation of 700% or more, more preferably 900% or more. In addition, the film according to the present embodiment preferably has a tensile strength per unit cross-sectional area of ​​0.23 N / (μm·cm) or more, more preferably 0.30 N / (μm·cm) or more. Furthermore, the film according to the present embodiment preferably has a tear strength per unit thickness of 0.015 N / μm or more, more preferably 0.045 N / μm or more.

[0030] In this embodiment, the tensile elongation and tensile strength of the film are measured as follows. The film to be measured is punched out in the direction of the tensile test to prepare a dumbbell-shaped No. 3 sample. The thickness of the necked portion of the sample is measured with a micrometer and the result is taken as thickness C (μm). The punched sample is fixed to a tensile tester (product name: AG-1S, manufactured by Shimadzu Corporation) with the chuck distance set to 50 mm. After fixing, the load read by the tensile tester is set to zero, and the sample is stretched at a deformation speed of 300 mm / min until it breaks. The tensile elongation and tensile strength are calculated by reading the elongation amount A (mm) and load B (N) during the stretching process from the obtained data, and combining them with the thickness C (μm) measured beforehand, as follows. The tensile elongation and tensile strength of the film are calculated as the average value of three samples for each of the MD and TD directions. Tensile elongation (%) = 100 x A (mm) / 20 mm Tensile strength (N / (μm cm))=B(N) / 0.5cm / C(μm)

[0031] In this embodiment, the tear strength of the film is measured as follows. The film is cut into a sample of 63 mm long x 76 mm wide to match the tear test direction, and the cut sample is fixed to an Elmendorf tear tester (analog type, manufactured by Toyo Seiki Seisakusho). The number of films to be fixed is adjusted appropriately so that the measurement result falls within 20 to 80% of the measurement range. The thickness of each film to be fixed is measured in advance using a micrometer, and the average value is taken as E (μm). The pendulum is lifted and stopped, and the pointer is set to the starting position. The sample is carefully attached to the gripping tool, and after the clamp is firmly tightened, a 20 mm long slit is made with an attached knife. The tear strength is calculated by carefully releasing the pendulum, converting the value of the scale D of the force required to tear the sample into tear strength (N) per sheet, and dividing it by the thickness E (μm) measured with a thickness gauge to calculate the tear strength per thickness (N / μm). The tear strength of the film is determined as the average value of three samples in each of the MD and TD directions.

[0032] In addition, the film according to this embodiment preferably has a good touch as a packaging film. In order to obtain a smooth touch, it is preferable that the MMD (variation of coefficient of friction) and SMD (surface roughness) by the KES surface test are small. In other words, the smaller the MMD and SMD of a film by the KES surface test, the smoother the touch. In the film according to this embodiment, there is a tendency that the higher the average aspect ratio of the flat phase, the smaller the MMD and SMD obtained. Specifically, in the film according to this embodiment, the MMD by the KES surface test is preferably 0.05 or less, more preferably 0.025 or less. In addition, in the film according to this embodiment, the SMD by the KES surface test is preferably 3.0 or less, more preferably 1.5 or less.

[0033] The method of the KES surface test according to this embodiment is as follows. A sample cut to 200 mm x 200 mm from the film to be measured is set in an automated surface tester (product name: KES-FB4-A-SE, manufactured by Kato Tech Co., Ltd.) so that the measurement surface is the outside of the balloon during inflation molding and the measurement direction is the MD direction, and tension is applied using a bar weight (147.8 g). Using the KES-FB SYSTEM data measurement program (KES-FB System Ver. 8.03WJ / For WinXP, 7), the device is operated at SENS STD and a speed of 0.1 cm / sec to measure friction and roughness, and the values ​​of MMD and SMD are read. The MMD and SMD of the film are calculated as the average values ​​of three samples. The friction measurement conditions are a static load of 50 gf and a dedicated 10 mm square piano wire sensor as the probe. The roughness measurement conditions are a static load of 10 gf and a dedicated 0.5 mm roughness sensor as the probe.

[0034] Furthermore, in the film according to the present embodiment, fine irregularities are formed, so that a unique visual texture with a matte feel is easily obtained compared to a film composed only of polyethylene. In this regard, in the film according to the present embodiment, in order to more effectively obtain such a visual texture as a packaging film, the surface gloss is preferably 80 or less, more preferably 30 or less. The gloss is measured by setting a gloss meter (product name: HP-300, manufactured by Time Group Co., Ltd.) on the film to be measured. However, when the measured value is 100 or more, the gloss is set to 100. The gloss of the film is calculated as the average value of the values ​​measured at five points. In addition, in the film according to the present embodiment, the fine irregularities scatter external light, thereby suppressing the transmission of ultraviolet rays, so that, for example, when used as a packaging film, the contents are less likely to deteriorate due to ultraviolet rays from sunlight, and high protection performance for the contents is easily obtained.

[0035] In addition, the film according to the present embodiment may be used as a packaging film with characters or patterns representing the product name or product information printed on the surface. In this regard, the film according to the present embodiment is preferably subjected to a surface treatment such as a corona treatment to obtain high printability on the surface, so that the surface wettability is 40 mN / m or more. The wettability is evaluated as surface energy. Specifically, to evaluate the wettability of the film, several centimeters of 40 mN / m dyne pen ink is applied to the film, and the state is observed to be maintained for 2 to 4 seconds. Specifically, the wettability of the film is determined to be 40 mN / m or more when the above observation is performed three times and the applied state is maintained without water droplets all three times.

[0036] [Film manufacturing method] An example of a film manufacturing method according to this embodiment will be described below with reference to Fig. 2, but the film manufacturing method according to this embodiment is not limited to the example shown in Fig. 2. The film manufacturing method shown in Fig. 2 includes a raw material preparation step (step S01), a kneading step (step S02), and a film molding step (step S03).

[0037] (Step S01: Preparation of raw materials) In step S01, raw materials for the film according to the present embodiment are prepared. Specifically, in step S01, a first raw material and a second raw material are prepared. The first raw material is a virgin material of polyethylene that constitutes the matrix phase. The second raw material is a recycled material containing polypropylene that constitutes the flat phase of the dispersed phase.

[0038] The first raw material can be prepared, for example, as pellets of commercially available polyethylene. The second raw material can be prepared, for example, as pellets obtained by repellentizing waste containing polypropylene. The repellentizing conditions for the second raw material can be appropriately determined depending on the physical properties of the components constituting the waste.

[0039] The second raw material preferably contains, for example, as a component constituting the spherical phase, at least one of a thermoplastic resin and a thermosetting resin having a melting point 100° C. or more higher than that of the first raw material. Such a component may contain, for example, at least one of polyethylene terephthalate and polyurethane.

[0040] The second raw material may contain at least one of a styrene-based elastomer, an ethylene-α-olefin copolymer, an olefin-based resin having a polar group introduced therein, and a styrene-based resin having a polar group introduced therein. Furthermore, the second raw material may contain an inorganic material that constitutes the inorganic material phase.

[0041] The viscosity ηA of the first raw material composed of polyethylene is adjusted according to the viscosity ηB of the polypropylene contained in the second raw material. More specifically, the viscosity ηA of the first raw material is adjusted based on the molding temperature during film molding in step S03, so that the ratio ηB / ηA of the viscosity ηB to the viscosity ηA at the molding temperature is 0.015 or more and less than 1.

[0042] The viscosity ηA of the first raw material and the viscosity ηB of the polypropylene contained in the second raw material are measured as follows. The resin is filled into the barrel of a Capirograph (product name: CAPIROGRAPH 1B, manufactured by Toyo Seiki Seisakusho) that has been heated to the measurement temperature in advance, and the viscosity value (Pa s) is read from the load when the resin is extruded at a speed of 10 mm / min with a piston in the "Capillary Flow Test" mode of the program "Capirograph of Windows (registered trademark)". A nozzle with a diameter of φ1 mm and a length of 10 mm and a barrel with a diameter of 9.55 mm are used.

[0043] (Step S02: Kneading) In step S02, the first and second raw materials prepared in step S01 are kneaded to produce a kneaded product. Figure 3 is a TEM image of a cross section of the kneaded product obtained in step S02, taken with a transmission electron microscope. In the structure shown in Figure 3, a light-colored dispersed phase is dispersed in a dark-colored matrix phase.

[0044] The matrix phase is mainly composed of polyethylene, and may contain polyethylene that is a component of the second raw material in addition to the polyethylene that is a component of the first raw material. In the structure shown in Figure 3, the dispersed phase mainly composed of polypropylene appears as relatively large circular regions, and the other dispersed phases appear as fine dot-like regions.

[0045] At the stage of the kneaded material obtained in step S02, the dispersed phase mainly composed of polypropylene is in a spherical shape with an average aspect ratio of not more than 3. In this embodiment, in the process of forming the kneaded material into a film in step S03, the dispersed phase mainly composed of polypropylene is made into a flat shape with an average aspect ratio of not less than 5, thereby forming a flat phase.

[0046] In the film according to the present embodiment, as described above, the polypropylene-based dispersed phase is made flat, so that the polypropylene is widely dispersed in the in-plane direction. Therefore, in the present embodiment, there is little need to increase the dispersibility of the polypropylene-based dispersed phase to a highly fine level in the kneading step S02.

[0047] For this reason, in step S02, it is preferable to use a single screw extruder rather than a sophisticated kneading technique using a twin screw extruder or the like, from the viewpoint of reducing the number of steps. This allows the production cost of the film according to the present embodiment to be reduced. However, if necessary, a twin screw extruder may be used, or a single screw extruder and a twin screw extruder may be used in combination.

[0048] In step S02, it is advantageous that the viscosity ratio between polyethylene and polypropylene is small and the interfacial tension between the matrix phase and the dispersed phase is small in order to make the dispersed phase fine. From this viewpoint, the kneading temperature in step S02 is preferably 200° C. or more and 300° C. or less. In step S02, it is preferable that the temperatures of all regions through which the raw materials pass, except for the raw material supply port, during the process of producing the kneaded product in the extruder are within the above range, but the temperature in some regions may be outside the above range.

[0049] (Step S03: Film Forming) In step S03, the kneaded material produced in step S02 is stretched thinly to form a film. The viscosity ηA of the first raw material is adjusted so that the ratio ηB / ηA of the viscosity ηB to the viscosity ηA at the forming temperature is 0.015 or more and less than 1, so that the dispersed phase mainly composed of polypropylene becomes a flat phase during the stretching of the kneaded material.

[0050] In other words, in this embodiment, by setting the ratio ηB / ηA at the molding temperature within the above range, the matrix phase is stretched without being affected by polypropylene, and at the same time, the dispersed phase mainly composed of polypropylene is deformed following the deformation of the matrix phase. As a result, the dispersed phase mainly composed of polypropylene that is thinly stretched together with the matrix phase becomes a flat phase.

[0051] In the film manufacturing method according to the present embodiment, it has been found that by relatively increasing the molding temperature of the kneaded material in step S03, the ratio ηB / ηA of the viscosity ηB to the viscosity ηA at the molding temperature tends to remain less than 1. In addition, a high molding temperature is advantageous in suppressing the force of the deformed flat phase returning to a spherical shape due to interfacial tension. However, if the molding temperature is raised too much, problems such as deterioration of moldability and deterioration of the resin occur. From these viewpoints, the molding temperature of the kneaded material in step S03 is preferably 200°C or more and 300°C or less, and more preferably 215°C or more and 280°C or less. In addition, when the raw material contains polyethylene terephthalate, it is preferable to set the molding temperature to a melting point of polyethylene terephthalate or more and melt the polyethylene terephthalate once. As a result, although fibrous polyethylene terephthalate is often contained in absorbent articles, polyethylene terephthalate contained in the raw material in a non-spherical form can also be made into a spherical phase.

[0052] FIG. 4 is a TEM image of the MD cross section of the film obtained in step S03, taken by a transmission electron microscope. FIG. 5 is a TEM image of the TD cross section of the film obtained in step S03, taken by a transmission electron microscope. The matrix phase is the same as the matrix phase of the kneaded material shown in FIG. 3. In FIGS. 4 and 5, the left-right and depth directions of the paper correspond to the in-plane directions of the film, and the up-down direction of the paper corresponds to the thickness direction of the film. In the structure shown in FIGS. 4 and 5, it can be seen that the circular dispersed phase mainly composed of polypropylene shown in FIG. 3 is stretched thinly to form a flat phase.

[0053] The method for forming the kneaded material into a film according to the present embodiment is not limited to a specific method, but it is preferable to use an inflation molding method. In the inflation molding method, since the film can be efficiently stretched not only in the MD direction but also in the TD direction, the influence of polypropylene can be suppressed not only in the MD direction but also in the TD direction.

[0054] The film molding machine used in the inflation molding method can be configured, for example, to be integrated with the extruder used for kneading, and to receive the kneaded material directly from the extruder. The molding temperature in inflation molding refers to the temperature of the kneaded material at the time when the kneaded material is discharged from the die. In inflation molding, the temperature of the kneaded material is preferably 200°C or more and 300°C or less, more preferably 215°C or more and 280°C or less, throughout the entire process from the time when the kneaded material is discharged from the extruder to the completion of the subsequent molding. However, in inflation molding, the temperature of the kneaded material may be outside the above range at any time other than the time when the kneaded material is discharged from the extruder.

[0055] [Other embodiments] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0056] For example, the film manufacturing method according to the present embodiment may include a process other than the above-mentioned process as necessary. For example, after the film forming process, a surface treatment may be performed to modify the surface of the film. An example of such a surface treatment is a corona treatment to improve the wettability of the surface of the film. In addition, after the film forming process, a slit may be formed or a bag making process may be performed.

[0057] In addition, in the film manufacturing method according to the present embodiment, a kneaded product obtained by adding other materials to recycled materials and kneading them may be used as the second raw material. Furthermore, in the film manufacturing method according to the present embodiment, the second raw material does not need to be a recycled material, and for example, virgin polypropylene material or a kneaded product obtained by adding other materials to this and kneading it may be used. In addition, in the film manufacturing method according to the present embodiment, the first raw material may not be a virgin material, but may be a recycled waste material containing polyethylene. Furthermore, in the film manufacturing method according to the present embodiment, other materials may be added and kneaded in the kneading step in addition to the first raw material and the second raw material.

[0058] Furthermore, in relation to the above-mentioned embodiment, the present invention further discloses the following configuration. <1> A film in which a dispersed phase is dispersed in a matrix phase, A matrix phase including polyethylene and a dispersed phase including polypropylene, The dispersed phase contains a flat phase oriented at least in the MD direction, and the average aspect ratio of the flat phase is 15 or more. film. <2> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the flat phase to the total cross-sectional area of ​​the dispersed phase is 60% or more. <1> The film according to claim 1. <3> The dispersed phase is composed of a resin and further includes a spherical phase having an aspect ratio of 3 or less. <1> or <2> The film according to claim 1. <4> The spherical phase contains at least one of polyethylene terephthalate and polyurethane. <3> The film according to claim 1. <5> The dispersed phase further comprises an inorganic material phase. <1> from <4> 13. The film according to claim 12, <6> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the polyethylene to the total cross-sectional area of ​​the film is 50% or more and 99% or less. <1> from <5> 13. The film according to claim 12, <7> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the polypropylene to the total cross-sectional area of ​​the film is 1% or more and 50% or less. <1> from <6> 13. The film according to claim 12, <8> Tensile elongation is 700% or more <1> from <7> 13. The film according to claim 12, <9> Tensile strength is 0.23N / (μm cm) or more <1> from <8> 13. The film according to claim 12, <10> Tear strength is 0.015N / μm or more <1> from <9> 13. The film according to claim 12, <11> MMD by KES surface test is 0.05 or less <1> from <10> 13. The film according to claim 12, <12> KES surface test SMD is 3.0 or less <1> from <11> 13. The film according to claim 12, <13> The surface gloss is 80 or less. <1> from <12> 13. The film according to claim 12, <14> Surface wettability is 40mN / m or more <1> from <13> 13. The film according to claim 12, <15> Part of the raw material is waste from absorbent products <1> from <14> 13. The film according to claim 12, <16> A method for producing a film having a dispersed phase dispersed in a matrix phase, comprising the steps of: A first raw material containing polyethylene and constituting the matrix phase and a second raw material containing polypropylene as a component constituting the dispersed phase are kneaded together, and the kneaded product is molded into a film; The ratio ηB / ηA of the viscosity ηB of the polypropylene contained in the second raw material at the molding temperature to the viscosity ηA of the first raw material at the molding temperature during the film molding is 0.015 or more and less than 1. A method for manufacturing a film. <17> The second material comprises waste from absorbent articles. <16> A method for producing the film according to claim 1. <18> The first raw material and the second raw material are kneaded using a single screw extruder. <16> or <17> A method for producing the film according to claim 1. <19> The kneaded material is molded into a film by inflation molding. <16> from <18> 13. A method for producing a film according to any one of the preceding claims. <20> The second raw material further contains, as a component constituting the dispersed phase, at least one of a thermoplastic resin and a thermosetting resin having a melting point 100° C. or more higher than that of the first raw material. <16> from <19> 13. A method for producing a film according to any one of the preceding claims. <21> After film formation, the surface of the film is subjected to corona treatment. <16> from <20> 13. A method for producing a film according to any one of the preceding claims. <22> The molding temperature is 200° C. or more and 300° C. or less. <16> from <21> 13. A method for producing a film according to any one of the preceding claims. <23> The flat phase is oriented in the MD and TD directions. <1> from <15> 13. The film according to claim 12, <24> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the polyethylene to the total cross-sectional area of ​​the film is 60% or more. <1> from <15> , and <23> 13. The film according to claim 12, <25> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the polypropylene to the total cross-sectional area of ​​the film is 40% or less. <1> from <15> , <23> , and <24> 13. The film according to claim 12, <26> The polyethylene content is 50% or more by mass. <1> from <15> , and <23> from <25> 13. The film according to claim 12, <27> The polypropylene content is 50% by mass or less. <1> from <15> , and <23> from <26> 13. The film according to claim 12, <28> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​polyethylene to the total cross-sectional area of ​​the film is 99% or less. <1> from <15> , and <23> from <27> 13. The film according to claim 12, <29> In an image of the film taken with a transmission electron microscope, the ratio of the total cross-sectional area of ​​the polypropylene to the total cross-sectional area of ​​the film is 1% or more. <1> from <15> , and <23> from <27> 13. The film according to claim 12, <30> The polyethylene content is 99% by mass or less. <1> from <15> , and <23> from <29> 13. The film according to claim 12, <31> The polypropylene content is 1% by mass or more. <1> from <15> , and <23> from <30> 13. The film according to claim 12, <32> The content of the resin constituting the spherical phase is 0.05% by mass or more and 20% by mass or less. <1> from <15> , and <23> from <31> 13. The film according to claim 12, <33> The average particle size of the spherical phase is 1 nm or more and 2 μm or less. <1> from <15> , and <23> from <32> 13. The film according to claim 12, <34> The dispersed phase includes a spherical phase containing at least one of a styrene-based elastomer, an ethylene-α-olefin copolymer (including those in which ethylene exists as a comonomer), an olefin-based resin having a polar group introduced therein, and a styrene-based resin having a polar group introduced therein. <1> from <15> , and <23> from <33> 13. The film according to claim 12, <35> The content of the resin constituting the phase, which includes at least one of a styrene-based elastomer, an ethylene-α-olefin copolymer (including those in which ethylene exists as a comonomer), an olefin-based resin having a polar group introduced therein, and a styrene-based resin having a polar group introduced therein, is 0.5% by mass or more and 15% by mass or less. <34> The film according to claim 1. <36> The material is made from waste materials derived from absorbent articles. Waste derived from absorbent articles is used as a raw material for at least the flat phase in the dispersed phase. <1> from <15> , and <23> from <35> 13. The film according to claim 12, <37> The film is used as a packaging film. <1> from <15> , and <23> from <36> 13. The film according to claim 12, <38> The surface gloss of the film is 80 or less. <1> from <15> , and <23> from <37> 13. The film according to claim 12,

[0059] [Examples and Comparative Examples] Examples and comparative examples of the above embodiment will be described below, but the present invention is not limited to the configurations of the following examples.

[0060] (raw materials) The following linear low density polyethylene (LLDPE) products with different melt flow rates (MFR) were used as virgin polyethylene (PE) materials constituting the first raw material. In Tables 1 to 5 below, MFRs are shown without units to distinguish between the various polyethylene (PE) products. The MFRs of polyethylene are shown as the manufacturer catalog values ​​for each product (190°C, load 2.16 kg). EVOLUE SP2510 (Prime Polymer, MFR: 1.5g / 10min) Evolue SP2020 (Prime Polymer, MFR: 2.3g / 10min) Evolue SP2540 (Prime Polymer, MFR: 3.8g / 10min) · UJ317 (Japan Polyethylene Corporation, MFR: 6.0g / 10min) -Ultsex 2520F (Prime Polymer, MFR: 2.2g / 10min)

[0061] Recycled materials 1 and 2 were used as recycled materials mainly composed of polypropylene (PP) that constitute the second raw material. The recycled material 1 is made by pelletizing scraps generated when cutting the crotch part during the manufacturing process of Kao Corporation's baby diapers, Merries (registered trademark) Pants Smooth Air Through L size (manufactured in 2022), using a single-screw extruder. The average composition of the recycled material 1 is 84% ​​by mass polypropylene (PP), 4% by mass styrene-based elastomer, and 2% by mass polyurethane (PU). The recycled material 2 is a pellet made by a single-screw extruder from scraps generated when cutting the rounded portion during the manufacturing process of the sanitary napkin Laurier (registered trademark) Shiawase Sohada, especially heavy day use, 25 cm, with wings (manufactured in 2022) manufactured by Kao Corporation. The average composition of the recycled material 2 is 30% by mass of polyethylene (PE), 35% by mass of polypropylene (PP), 2% by mass of polyethylene terephthalate (PET), and 28% by mass of calcium carbonate. The raw material composition of the recycled material may vary depending on the product composition from which it is generated, but it is preferable from the viewpoint of film quality and reduction of virgin materials that the blending ratio of the recycled material to the first raw material is controlled to a range of 20 to 50% by mass of PP in the film, 0 to 5% by mass of PET in the film, 0 to 5% by mass of PU in the film, and the total of the resins is 50% or less.

[0062] The following products with different melt flow rates (MFR) were used as virgin polypropylene (PP) materials that make up the second raw material. In Tables 4 and 5 below, MFRs are shown without units to distinguish between each polypropylene product. The MFR of polypropylene is shown as the manufacturer's catalog value for each product (230°C, load 2.16 kg). · F300SP (Prime Polymer, MFR: 2g / 10min) PM600A (SunAllomer, MFR: 7.5g / 10min) 3155E3 (ExxonMobil, MFR: 36g / 10min) PLB00A (SunAllomer, MFR: 70g / 10min) MF650Y (LyondellBasel, MFR: 1800g / 10min)

[0063] As the polyethylene terephthalate (PET), TRN-RTJ (manufactured by Teijin Ltd.) was used. The dispersion assistants used were Dispersion Assistants 1 and 2. Vistamaxx Performance Polymer 7050BF (manufactured by ExxonMobil Corporation), an ethylene-propylene copolymer, was used as Dispersion Assistant 1. Tuftec M C5025 (manufactured by Asahi Kasei Corporation), a maleic anhydride-modified hydrogenated styrene-based thermoplastic elastomer, was used as Dispersion Assistant 2. Calcium carbonate and titanium oxide were used as inorganic materials constituting the inorganic material phase. Specifically, calcium carbonate was used from a re-pelletized product of production losses from moisture permeable film for Merry's baby diapers manufactured by Kao Corporation (a compound of Ultzex ​​2520F (manufactured by Prime Polymer Co., Ltd., MFR: 2.2 g / 10 min) and calcium carbonate). Titanium oxide was used as titanium oxide master TET1TA538WHT-FD (manufactured by Toyo Color Co., Ltd.). In the following Tables 1 to 5, the content of each raw material is shown as a mass ratio.

[0064] (Analysis method) For some of the films made from the above raw materials, evaluation was performed using TEM images to analyze the dispersed phase. Specifically, for each film, the total cross-sectional area ratio of the dispersed phase to the entire film (dispersed phase / whole film) was determined. In addition, for each film, the average aspect ratio of the flat phase and the total cross-sectional area ratio of the flat phase to the entire dispersed phase (flat phase / dispersed phase) were determined. Furthermore, for each film, the total cross-sectional area ratio of the spherical phase to the entire dispersed phase (spherical phase / dispersed phase) was determined.

[0065] (Evaluation method) The methods for measuring the tensile elongation and tensile strength, the method for measuring the tear strength, the method for the KES surface test, and the method for measuring the glossiness are as described in the above embodiment.

[0066] (Reference Examples and Comparative Examples) As the reference examples and comparative examples, films were produced using the raw materials and production conditions shown in Table 1. In both the reference examples and comparative examples, a single screw extruder was used for kneading, and an inflation molding method was used for molding. The film according to the reference example is different from the above-mentioned embodiment in that it is composed only of polyethylene (PE) and has a structure that provides good quality as a general film. In other words, the film according to the comparative example 1 serves as a good quality standard for evaluating the films according to the examples. The film according to the comparative example differs from the above embodiment in that the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) is 1 or more. Fig. 6 shows a TEM image of the MD cross section of the film according to the comparative example. In the film according to the comparative example, the average aspect ratio of the flat phase obtained from the TEM image shown in Fig. 6 was 12.3, which was smaller than that of the above embodiment.

[0067] Table 1 shows the evaluation results of the films according to the Reference Example and the Comparative Example. The film according to the Comparative Example had lower tensile elongation, tensile strength, and tear strength than the film according to the Reference Example. In particular, the film according to the Comparative Example had a significantly lower tensile elongation, making it difficult to use it as a packaging film. In addition, the film according to the Comparative Example had higher MMD and SMD by the KES surface test than the film according to the Reference Example, and was found to have a rough texture. Accordingly, it is believed that the film according to the Comparative Example had a significantly lower gloss than the film according to the Reference Example.

[0068] [Table 1]

[0069] (Examples 1 to 7) As Examples 1 to 7, films were produced using the production conditions and raw materials shown in Table 2. In all of Examples 1 to 7, a single screw extruder was used for kneading, and an inflation molding method was used for molding. In all of Examples 1 to 7, recycled material 1 was used as the second raw material. In all of the films according to Examples 1 to 7, the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) fell within the range of the above embodiment.

[0070] FIG. 7 shows a TEM image of the MD cross section of the film according to Example 4. In the film according to Example 4, the average aspect ratio of the flat phase determined from the TEM image shown in FIG. 7 was 29.5, and the average aspect ratio of the spherical phase formed of polyurethane (PU) was 1. In the film according to Example 1, the average aspect ratio of the flat phase determined from the TEM image was 66.5, and the average aspect ratio of the spherical phase formed of polyurethane (PU) was 1. In both of the films according to Examples 1 and 4, the total cross-sectional area ratio of the flat phase to the entire dispersed phase was 80% or more.

[0071] Table 2 shows the evaluation results of the films according to Examples 1 to 7. All of the films according to Examples 1 to 7 had a significantly higher tensile elongation than the film according to the Comparative Example. In addition, the evaluation results of Examples 1 to 7 showed a tendency that the tensile elongation of the film was higher when the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) was smaller. Furthermore, all of the films according to Examples 1 to 7 had lower MMD and SMD by the KES surface test than the film according to the Comparative Example, and it was found that a good feel was obtained. In addition, it was found that all of the films according to Examples 1 to 7 had a lower gloss than the film according to the Reference Example, and had a matte visual texture.

[0072] [Table 2]

[0073] (Examples 8 to 10) For Examples 8 to 10, films were produced using the production conditions and raw materials shown in Table 3. For all of Examples 8 to 10, a single screw extruder was used for kneading, and an inflation molding method was used for molding. For all of Examples 8 to 10, recycled material 1 was used as the second raw material. In Examples 8 and 9, calcium carbonate was further used as the inorganic material constituting the inorganic material phase. In Example 10, titanium oxide was further used as the inorganic material constituting the inorganic material phase. For all of the films according to Examples 8 to 10, the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) fell within the range of the above embodiment.

[0074] Table 3 shows the evaluation results of the films according to Examples 8 to 10. All of the films according to Examples 8 to 10 had a significantly higher tensile elongation than the film according to the Comparative Example. In addition, all of the films according to Examples 8 to 10 had lower MMD and SMD by the KES surface test than the film according to the Comparative Example, and it was found that a good feel was obtained. Furthermore, all of the films according to Examples 8 to 10 had a lower gloss than the film according to the Reference Example, and it was found that a matte visual texture was obtained.

[0075] [Table 3]

[0076] (Examples 11 to 24) In Examples 11 to 24, films were produced using the manufacturing conditions and raw materials shown in Tables 4 and 5. In all of Examples 11 to 24, a single screw extruder was used for kneading, and an inflation molding method was used for molding. In all of Examples 11 to 24, virgin polypropylene (PP) material was used as the second raw material. In Examples 11 to 16, the kneading temperature and molding temperature were 230°C. In Examples 17 to 21, the kneading temperature and molding temperature were 200°C. In Examples 22 to 24, polyethylene terephthalate (PET) was further used as the resin constituting the spherical phase, and the kneading temperature and molding temperature were 270°C. In all of the films according to Examples 11 to 24, the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) was within the range of the above embodiment. In all of Examples 22 to 24, the ratio of the viscosity of polyethylene terephthalate (PET) to the viscosity ηA of polyethylene (PE) at the molding temperature was 0.11.

[0077] FIG. 8 shows a TEM image of the MD cross section of the film according to Example 24. In the film according to Example 24, the average aspect ratio of the flat phase obtained from the TEM image shown in FIG. 8 was 24.5, and the average aspect ratio of the spherical phase formed of polyethylene terephthalate (PET) was 2. In the film according to Example 17, the average aspect ratio of the flat phase obtained from the TEM image was 16.5. In the film according to Example 21, the average aspect ratio of the flat phase obtained from the TEM image was 52.7. In the films according to Examples 17, 21, and 24, the total cross-sectional area ratio of the flat phase to the entire dispersed phase was 60% or more.

[0078] Tables 4 and 5 show the evaluation results of the films according to Examples 11 to 24. All of the films according to Examples 11 to 24 had a significantly higher tensile elongation than the films according to the Comparative Example. In addition, when the evaluation results of Examples 13 and 19 were compared with those of Examples 22 to 24, it was found that the tear strength was significantly improved by using polyethylene terephthalate (PET). Furthermore, all of the films according to Examples 11 to 24 had lower MMD and SMD by the KES surface test than the films according to the Comparative Example, and it was found that a good feel was obtained. In addition, it was found that all of the films according to Examples 11 to 24 had a lower gloss than the films according to the Reference Example, and had a matte visual texture.

[0079] [Table 4]

[0080] [Table 5]

[0081] (Examples 25 to 27) As Examples 25 to 27, films were produced under the manufacturing conditions and using the raw materials shown in Table 6. In Example 25, a single screw extruder was used for kneading, and an inflation molding method was used for molding. In Example 25, recycled material 2 was used as the second raw material. In Example 26, a single screw extruder and a twin screw extruder were used in combination for kneading, and an inflation molding method was used for molding. More specifically, in Example 26, kneading was performed using a twin screw extruder before kneading using a single screw extruder. In Example 26, recycled material 1 was used as the second raw material, and titanium oxide was used as the inorganic material constituting the inorganic material phase. In Example 27, a single screw extruder was used for kneading, and a T-die molding method was used for molding. In Example 27, recycled material 1 was used as the second raw material. In all of the films according to Examples 25 to 27, the ratio ηB / ηA of the viscosity ηB of polypropylene (PP) to the viscosity ηA of polyethylene (PE) was within the range of the above embodiment.

[0082] In the film of Example 26, the average aspect ratio of the flat phase determined from the TEM image in the same manner as above was 30.0, and the average aspect ratio of the spherical phase formed of polyurethane (PU) was 1. In addition, in the film of Example 26, the total cross-sectional area ratio of the flat phase to the entire dispersed phase was 80% or more.

[0083] Table 6 shows the evaluation results of the films according to Examples 25 to 27. All of the films according to Examples 25 to 27 had a significantly higher tensile elongation than the film according to the Comparative Example. In addition, all of the films according to Examples 25 to 27 had lower MMD and SMD by the KES surface test than the film according to the Comparative Example, and it was found that a good feel was obtained. Furthermore, all of the films according to Examples 25 to 27 had a lower gloss than the film according to the Reference Example, and it was found that a matte visual texture was obtained.

[0084] [Table 6] [Industrial Applicability]

[0085] According to the present invention, in a film in which polypropylene is dispersed in polyethylene, deterioration in quality caused by polypropylene can be suppressed.

Claims

1. A film in which a dispersed phase is dispersed in a matrix phase, comprising a matrix phase containing polyethylene and a dispersed phase containing polypropylene, wherein the dispersed phase comprises a flat phase oriented at least in the MD direction and composed of a resin, and a spherical phase having an aspect ratio of 3 or less, and the average aspect ratio of the flat phase is 15 or more film.

2. A film in which a dispersed phase is dispersed in a matrix phase, comprising a matrix phase containing polyethylene and a dispersed phase containing polypropylene, wherein the dispersed phase comprises a flat phase oriented at least in the MD direction, and the average aspect ratio of the flat phase is 15 or more, using waste derived from absorbent articles as part of the raw materials film.

3. The film according to claim 1, wherein the spherical phase comprises at least one of polyethylene terephthalate and polyurethane. The film according to claim 1.

4. The film according to any one of claims 1 to 3, wherein the ratio of the total cross-sectional area of the flat phase to the total cross-sectional area of the dispersed phase in an image obtained by imaging the film with a transmission electron microscope is 60% or more. The film according to any one of claims 1 to 3.

5. The film according to any one of claims 1 to 3, wherein the dispersed phase further comprises an inorganic material phase. The film according to any one of claims 1 to 3.

6. The film according to any one of claims 1 to 3, wherein the ratio of the total cross-sectional area of polyethylene to the total cross-sectional area of the film in an image obtained by imaging the film with a transmission electron microscope is 50% or more and 99% or less. The film according to any one of claims 1 to 3.

7. The film according to any one of claims 1 to 3, wherein the ratio of the total cross-sectional area of polypropylene to the total cross-sectional area of the film in an image obtained by imaging the film with a transmission electron microscope is 1% or more and 50% or less. The film according to any one of claims 1 to 3.

8. A method for manufacturing a film in which a dispersed phase is dispersed in a matrix phase, wherein a kneaded product obtained by kneading a first raw material containing polyethylene and constituting the matrix phase and a second raw material containing polypropylene as a component constituting the dispersed phase is formed into a film, and the ratio ηB / ηA of the viscosity ηB of polypropylene contained in the second raw material at the forming temperature to the viscosity ηA of the first raw material at the forming temperature is 0.015 or more and less than 1, and the second raw material further comprises at least one of a thermoplastic resin and a thermosetting resin having a melting point 100°C or higher than that of the first raw material as a component constituting the dispersed phase. Method for manufacturing a film.

9. A method for manufacturing a film in which a dispersed phase is dispersed in a matrix phase, comprising polyethylene, a first raw material constituting the matrix phase, and a second raw material containing polypropylene as a component constituting the dispersed phase, and forming a film from a kneaded product obtained by kneading the two raw materials, wherein the ratio ηB / ηA of the viscosity ηB of polypropylene contained in the second raw material at the forming temperature to the viscosity ηA of the first raw material at the forming temperature during the film forming is 0.015 or more and less than 1, and the second raw material contains waste derived from an absorbent article A method for manufacturing a film.

10. Kneading the first raw material and the second raw material using a single-screw extruder The method for manufacturing a film according to claim 8 or 9.

11. Forming the kneaded product into a film by an inflation molding method The method for manufacturing a film according to claim 8 or 9.

12. Performing a corona treatment on the surface of the film after film forming The method for manufacturing a film according to claim 8 or 9.

13. The forming temperature is 200°C or higher and 300°C or lower The method for manufacturing a film according to claim 8 or 9.

Images