JP2022158979A - Production method of film - Google Patents

Abstract

To provide a production method of a film capable of producing a high-quality film from a recycled raw material.SOLUTION: A production method of a film includes a recycle pelletizing step for pelletizing a mixed material containing a recycled raw material containing a crushed film and a virgin raw material of an optional layer of a film to be produced to produce a recycled pellet, a measuring step for measuring fluidity of the recycled pellet, a determination step for determining an article number to be produced among a plurality of article numbers of the film based on the fluidity of the recycled pellet, and a production step for producing the film of the article number determined in the determination step from the recycled pellet.SELECTED DRAWING: Figure 3

Description

The present invention relates to a film manufacturing method.

Patent Document 1 measures the fluidity of the recycled raw material, manages the recycled raw material whose fluidity is within the first range for the first shipment, and manages the recycled raw material whose fluidity is within the second range for the second shipment. It discloses a quality control method that manages as

JP 2020-168855 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a film manufacturing method capable of manufacturing a high-quality film using recycled raw materials.

A method for producing a film according to the first aspect of the present invention is a method of producing recycled pellets by pelletizing a mixed material containing a recycled raw material containing crushed films and a virgin raw material of an arbitrary layer of the film to be produced. A pelletizing step, a measuring step of measuring the fluidity of the recycled pellets, a determination step of determining the product number to be manufactured from a plurality of product numbers of the film based on the fluidity of the recycled pellets, and the recycled pellets. and a manufacturing step of manufacturing a film of the product number determined in the determining step, using the manufacturing method.

Since the weight average molecular weight of the recycled raw material is smaller than that of the virgin raw material, it is difficult to produce a high quality film using only the recycled raw material. In the film production method, recycled pellets containing virgin raw materials are used to produce the film. Since the weight-average molecular weight of the recycled pellets is maintained at a certain level, it is possible to produce a film of higher quality than when producing a film using only recycled raw materials.

A film manufacturing method according to a second aspect of the present invention is the film manufacturing method according to the first aspect, wherein in the manufacturing step, the film raw material obtained by mixing the recycled pellets and the virgin raw material is used to produce the A film having the product number determined in the determination step is manufactured.

In the film manufacturing method described above, a film raw material obtained by further mixing a virgin raw material with a recycled pellet is used for manufacturing a film. Therefore, a higher quality film can be produced.

A method for producing a film according to a third aspect of the present invention is the method for producing a film according to the second aspect, wherein in the production step, the difference between the fluidity of the recycled pellets and the fluidity of the arbitrary layer Based on, the mixing ratio of the recycled pellets and the virgin raw material is determined.

The smaller the difference between the fluidity of the recycled pellets and the fluidity of any layer, the smaller the proportion of the virgin raw material in the film raw material. On the other hand, in order to produce a high-quality film, the greater the difference between the fluidity of the recycled pellets and the fluidity of any layer, the greater the proportion of the virgin material in the film material. In the film manufacturing method described above, the mixing ratio of the recycled pellets and the virgin raw material can be appropriately determined.

A method for manufacturing a film according to a fourth aspect of the present invention is the method for manufacturing a film according to the third aspect, wherein in the manufacturing step, the fluidity of the film raw material is a predetermined fluidity including the fluidity of the arbitrary layer The mixing ratio of the recycled pellets and the virgin raw material is determined so as to fall within the range.

According to the film manufacturing method described above, the proportion of recycled pellets in the film raw material can be increased.

A method for manufacturing a film according to a fifth aspect of the present invention is the method for manufacturing a film according to the fourth aspect, wherein in the manufacturing step, the fluidity of the film raw material is such that the fluidity of the arbitrary layer at the first temperature The mixing ratio of the regenerated pellets and the virgin raw material is adjusted so as to be included in the first predetermined range including the fluidity and to be included in the second predetermined range including the fluidity of the arbitrary layer at the second temperature. decide.

According to the film manufacturing method described above, since the fluidity of the film raw material at a plurality of temperatures is close to the fluidity of any layer, a higher quality film can be manufactured.

In the film manufacturing method according to the sixth aspect of the present invention, in the determining step, in addition to the fluidity of the recycled pellets, at least one of the optical properties, color appearance, purity, and shape of the recycled pellets. to determine the product number to be manufactured from the plurality of product numbers of the film.

According to the film manufacturing method described above, since the product number of the film to be manufactured is determined based on detailed viewpoints, it is possible to manufacture a higher quality film.

A method for producing a film according to a seventh aspect of the present invention includes a measurement step of measuring the fluidity of a mixed material containing recycled raw materials including crushed films and virgin raw materials of any layer of the film to be produced; A determination step of determining a product number to be manufactured from a plurality of product numbers of the film based on the fluidity of the film, and a manufacturing step of manufacturing the film of the product number determined in the determination step using the mixed material. include.

Since the weight average molecular weight of the recycled raw material is smaller than that of the virgin raw material, it is difficult to produce a high quality film using only the recycled raw material. In the film manufacturing method described above, a mixed material containing a virgin raw material is used for manufacturing the film. Since the weight-average molecular weight of the mixed material is maintained at a certain level, a film of higher quality can be produced compared to the production of a film using only recycled raw materials.

A film manufacturing method according to an eighth aspect of the present invention is the film manufacturing method according to the seventh aspect, wherein in the determination step, in addition to the fluidity of the mixed material, the optical properties of the mixed material, color A product number to be manufactured is determined from a plurality of product numbers of the film based on at least one of appearance, purity, and shape.

According to the film manufacturing method described above, since the product number of the film to be manufactured is determined based on detailed viewpoints, it is possible to manufacture a higher quality film.

A film manufacturing method according to a ninth aspect of the present invention is the film manufacturing method according to any one of the first to eighth aspects, wherein the crushed film is subjected to deinking treatment.

According to the film manufacturing method described above, since the crushed film does not have a printed layer, a higher quality film can be manufactured.

According to the film manufacturing method of the present invention, a high-quality film can be manufactured using recycled raw materials.

Sectional drawing of a film. The table|surface which shows the relationship between the product number of a film, and the fluidity|liquidity of an inner layer. 4 is a flow chart showing an example of a film manufacturing process.

Hereinafter, a method for manufacturing a film according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
<1. Overview>
FIG. 1 is a cross-sectional view showing an example of the layer structure of the film 100. As shown in FIG. The film 100 includes outer layers 10 , 20 , an inner layer 30 and an adhesive layer 40 . The material forming the outer layers 10 and 20 is, for example, a polyester-based resin. Polyester-based resins are, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or polybutylene naphthalate. In this embodiment, the material forming the outer layers 10, 20 is polyethylene terephthalate. The inner layer 30 is laminated between the outer layer 10 and the outer layer 20 . A material forming the inner layer 30 is, for example, a styrene-based resin. Styrenic resins are, for example, polystyrene, acrylonitrile styrene, acrylonitrile butadiene styrene, or copolymers with conjugated dienes. In this embodiment, the material forming the inner layer 30 is polystyrene. The adhesive layer 40 includes a first adhesive layer 41 and a second adhesive layer 42 . The first adhesive layer 41 bonds the outer layer 10 and the inner layer 30 together. The second adhesive layer 42 joins the outer layer 20 and the inner layer 30 . The material forming the adhesive layer 40 is, for example, an adhesive such as a polyester-based elastomer. The film 100 is used by laminating a printed layer on which descriptions about the product and the like are written at an arbitrary position and sticking it to a PET bottle or the like.

FIG. 2 is a table showing the relationship between the product number of the film 100 and the fluidity of the inner layer 30. As shown in FIG. The film 100 has a plurality of product numbers with different ratios of the inner layer 30 to the outer layer 10 and the outer layer 20, for example, even if the layer structure is the same. The multiple product numbers include, for example, product number A101, product number A102, and product number A103. In the films 100 with product numbers A101, A102, and A103, the fluidity of the inner layer 30 at the first temperature TA and the second temperature TB is different. An index for evaluating the fluidity of the inner layer 30 is MFR (Melt Flow Rate), for example. The fluidity of inner layer 30 is measured by a known melt flow indexer. In this embodiment, the second temperature TB is higher than the first temperature TA. The second temperature TB is preferably the temperature of the resin when passing through a die when the film 100 is extruded. Note that the MFR values shown in FIG. 2 are examples.

Laminated films, such as film 100, that include multiple types of layers are generally known. In general, a film produced using a recycled raw material obtained from a laminated film deteriorates in appearance and deteriorates in film performance, for example, and thus it is difficult to recycle the laminated film.

In the method for producing a film of the present embodiment, since it is devised, it is possible to produce a high-quality film even if the recycled raw material recovered from the laminated film is used. Hereinafter, the method for manufacturing the film of this embodiment will be described in detail.

<2. Film production method>
FIG. 3 is a flow chart showing an example of the film manufacturing process in the film manufacturing method of the present embodiment. Prior to the steps shown in this flow chart, a deinking process for removing the printed layer is performed on the waste film. The waste film that has undergone the deinking treatment is pulverized and becomes a recycled raw material containing a large number of film pieces (hereinafter referred to as "crushed film"). The recycled material includes the outer layers 10, 20, the inner layer 30, and the adhesive layer 40. In this embodiment, a case of using a recycled raw material as a material for forming the inner layer 30 will be described.

In step S11 (re-pelletizing step), the mixed material containing the recycled raw material including the crushed film and the virgin raw material of the inner layer 30 is pelletized by the film manufacturing apparatus to manufacture recycled pellets. The proportion of the virgin raw material in the mixed material can be arbitrarily selected within the range of 10% to 90%. From the viewpoint of quality and productivity, etc., the ratio of the virgin raw material in the mixed material is preferably 20% to 80%, more preferably 20% to 50%.

In step S12 (measurement step), the melt flow indexer measures the MFR value of the recycled pellets. In step S12, the MFR values of the regenerated pellets at the first temperature TA and the second temperature TB are measured. The MFR value of the recycled pellets is, for example, "JIS K7210-1 Plastics - How to determine the melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics - Part 1: Standard test method". can be measured based on

In step S13 (determination step), the product number of the film 100 to be manufactured is determined from the product numbers A101 to A103 of the film 100 based on the MFR value of the recycled pellets measured in step S12. In this embodiment, in step S13, the product number of the film 100 to be manufactured is determined by comparing the MFR value of the inner layer 30 at the second temperature TB and the MFR value of the recycled pellets at the second temperature TB. The product number of the film 100 to be manufactured may be determined by comparing the MFR value of the inner layer 30 at the first temperature TA and the MFR value of the recycled pellets at the first temperature TA.

For example, if the MFR value of the recycled pellet at the second temperature TB is the closest to the MFR value of the inner layer 30 of the film of product number A101, product number A101 is determined as the product number of the film 100 to be manufactured. If the MFR value of the recycled pellet at the second temperature TB is the closest to the MFR value of the inner layer 30 of the film of product number A102, product number A102 is determined as the product number of the film 100 to be manufactured. If the MFR value of the recycled pellet at the second temperature TB is closest to the MFR value of the inner layer 30 of the film of product number A103, product number A103 is determined as the product number of the film 100 to be manufactured. In step S13, the product number of the film 100 to be manufactured may be determined by the operator, or the product number of the film 100 to be manufactured may be determined by the computer executing a program stored in the storage device.

In step S14 (manufacturing step), a film raw material is manufactured by mixing the recycled pellets and the virgin raw material of the inner layer 30 by the manufacturing apparatus. The mixing ratio of the recycled pellets and the virgin raw material is preferably determined based on the difference between the MFR value of the recycled pellets and the MFR value of the inner layer 30 of the product number of the film 100 to be manufactured. For example, the mixing ratio is determined such that the smaller the difference between the MFR value of the recycled pellets and the MFR value of the inner layer 30 of the product number of the film 100 to be produced, the smaller the proportion of the virgin raw material in the film raw material. The mixing ratio is determined such that the greater the difference between the MFR value of the recycled pellets and the MFR value of the inner layer 30 of the product number of the film 100 to be manufactured, the greater the proportion of the virgin raw material in the film raw material.

In step S<b>14 , it is preferable that the mixing ratio of the recycled pellets and the virgin raw material is determined so that the MFR value of the film raw material is within a predetermined range including the MFR value of the inner layer 30 . The predetermined range is a range in which the high quality of the film 100 can be maintained. The predetermined range includes a first predetermined range and a second predetermined range. The first predetermined range is a range whose median value is the MFR value at the first temperature TA shown in FIG. The second predetermined range is a range whose median value is the MFR value at the second temperature TB shown in FIG. The first predetermined range and the second predetermined range are, for example, a range of −20 g/10 min to +20 g/10 min with the MFR value of the inner layer 30 as the median. Generally, the MFR value of recycled pellets is higher than the MFR value of the virgin raw material, so the film raw material in which the recycled pellets and the virgin raw material are mixed has a higher MFR value than the inner layer 30 shown in FIG. . In step S14, it is preferable that the mixing ratio of the recycled pellets and the virgin raw material is determined so that the MFR value of the film raw material falls within the first predetermined range and the second predetermined range.

In step S15 (manufacturing step), the film 100 is manufactured using the film raw material by the manufacturing apparatus.

<3. Effects of the First Embodiment>
In the film manufacturing method of the first embodiment, recycled pellets containing virgin raw materials are used for film manufacturing. Since the weight-average molecular weight of the recycled pellets is maintained at a certain level, it is possible to produce a film of higher quality than when producing a film using only recycled raw materials.

[Second embodiment]
The film manufacturing method of the second embodiment differs from the first embodiment in that it does not have the re-pelletizing step S11, and the rest of the configuration is substantially the same as that of the first embodiment. Below, descriptions of the same contents as in the first embodiment will be omitted, and descriptions will focus on portions that differ from the first embodiment.

In the film manufacturing method of the second embodiment, the re-pelletizing step S11 of the first embodiment is omitted, and in the measurement step S12, the recycled raw material including the crushed film and the virgin raw material of any layer of the film to be manufactured are separated. The fluidity of the containing mixed material is measured. The film manufacturing method of the present embodiment is realized by replacing the wording of recycled pellets in the description of determination step S13 and manufacturing steps S14 and S15 of the first embodiment with mixed material.

In the film manufacturing method of the second embodiment, since the crushed film is not pelletized, the recycled raw material has little heat history. Higher quality films can be produced because recycled raw materials do not easily deteriorate.

[Third embodiment]
The film manufacturing method of the third embodiment differs from that of the first embodiment in determination step S13, and the other configurations are substantially the same as those of the first embodiment. Below, descriptions of the same contents as in the first embodiment will be omitted, and descriptions will focus on portions that differ from the first embodiment. Note that the determination step S13 of the present embodiment can be similarly applied to the second embodiment by replacing the words "recycled pellets" with "mixed material."

In the determination step S13 of the film manufacturing method of the third embodiment, in addition to the fluidity of the recycled pellets, a plurality of product numbers of the film is determined based on at least one of the optical properties, color appearance, purity, and shape of the recycled pellets. Determine the product number to be manufactured.

The optical properties of the recycled pellets include, for example, at least one of haze, gloss, and total light transmittance. When a film is produced using recycled pellets with low optical properties, the optical properties of the film deteriorate. For this reason, by determining the product number to be manufactured in consideration of the optical characteristics of the recycled pellets, it is possible, for example, to limit the amount of recycled pellets with low optical characteristics used, or to demand high quality recycled pellets with low optical characteristics. can be preferentially used for the production of films that cannot be

The color of the recycled pellets includes, for example, color values. The color value can be measured based on, for example, "JIS Z8730 Color display method-color difference of object color". Since the regenerated pellets with low color value, in other words, deteriorated, are yellowed, the produced film is also yellowed. For this reason, by determining the product number to be manufactured in consideration of the color of the recycled pellets, for example, it is possible to limit the amount of recycled pellets with low color values used, or to require high quality recycled pellets with low color values. can be preferentially used for the production of films that cannot be

The purity of the recycled pellets includes, for example, at least one of moisture content, ash content, PH value, density, and number of defects.

The moisture content is measured, for example, by the loss-on-drying method. If the recycled pellets contain a large amount of water, air bubbles may be generated during film formation. For this reason, by determining the product number to be manufactured considering the moisture content of the recycled pellets, for example, when using recycled pellets with a high moisture content, by performing a drying process in advance, a high-quality film can be manufactured. can.

The ash content can be measured, for example, based on "JIS K2272 Crude oil and petroleum products-Ash content and sulfated ash test method". By measuring the ash content of the recycled pellets, the amount of impurities that cause defects can be quantified. For this reason, by determining the product number to be manufactured considering the ash content of the recycled pellets, for example, it is possible to limit the amount of recycled pellets with a high ash content, or to use recycled pellets with a high ash content as a film that does not require high quality. can be preferentially used for the production of

The PH value is obtained, for example, by putting the crushed film into pure water at a predetermined concentration, stirring for a certain period of time, and then measuring the PH value of the liquid. An alkaline aqueous solution is generally used for deinking waste films. If an alkaline aqueous solution adheres to the surface of the deinked crushed film, the raw material (mainly polyethylene terephthalate and nylon) may be hydrolyzed when the crushed film is fed into the extruder. . For this reason, by determining the product number to be manufactured in consideration of the PH value of the crushed film, for example, when using a crushed film with a high PH value, it should be washed with water in advance to remove the residue of the alkaline aqueous solution. allows the production of high quality films.

Density can be measured, for example, based on "JIS K7112 Plastics - Determination of density and specific gravity of non-foamed plastics". If the density of the recycled pellets is low, air bubbles may be generated during film formation. For this reason, by determining the product number to be manufactured in consideration of the density of the recycled pellets, for example, it is possible to limit the amount of recycled pellets with low density used, or to use recycled pellets with low density for films that do not require high quality. can be preferentially used for the production of By adjusting the degree of vacuum and the melting temperature during production of recycled pellets, production of recycled pellets with low density can be suppressed.

The number of defects is determined, for example, by manufacturing a sample sheet by melt extrusion using recycled pellets, and counting the number of defects for each predetermined interval of the sample sheet with an inspection machine installed in front of the sample sheet winding device. measured. If the number of defects in the recycled pellets is large, the quality of the film will be degraded. For this reason, by determining the product number to be manufactured in consideration of the number of defects of the recycled pellets, for example, the amount of recycled pellets with a large number of defects used is limited, or the quality of recycled pellets with a large number of defects is required. can be preferentially used for the production of films that cannot be

The shape of the regenerated pellets includes, for example, size. The size is defined, for example, based on the weight of a predetermined number of regenerated pellets. If there is a large variation in the size of the recycled pellets, there is a risk that the recycled raw material will be transported poorly, or that mixing defects will occur when mixed with the virgin raw material. Therefore, by determining the product number to be manufactured in consideration of the size of the recycled pellets, it is possible to suppress, for example, the use of recycled pellets with large variations in size. It should be noted that by adjusting the pelletizing speed and extrusion rate during production of recycled pellets, it is possible to suppress variations in size of recycled pellets.

<4. Variation>
Each of the above-described embodiments is an illustration of possible forms of the method for producing a film according to the present invention, and is not intended to limit the forms. The method for producing a film according to the present invention may take forms different from those exemplified in each embodiment. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to the embodiment. Some examples of modifications of each embodiment are shown below. Note that the following modifications can be combined with each other within a technically consistent range.

<4-1>
In the first embodiment, in step S14 of the film manufacturing process, the mixing ratio of the recycled pellets and the virgin raw material is determined so that the MFR value of the film raw material falls within the first predetermined range and the second predetermined range. . However, the method of determining the mixing ratio of the recycled pellets and the virgin raw material is not limited to this. For example, in step S14 of the film manufacturing process, the mixing ratio of the recycled pellets and the virgin raw material may be determined so that the MFR value of the film raw material falls within only one of the first predetermined range and the second predetermined range.

<4-2>
In the first embodiment described above, in step S14 of the film manufacturing process, the recycled pellets are further mixed with the virgin raw material, but the film manufacturing process is not limited to this. For example, if the difference between the MFR value of the recycled pellets and the MFR value of the inner layer 30 of the product number of the film 100 to be manufactured is sufficiently small, step S14 is omitted, and in step S15, the inner layer 30 is formed using only the recycled pellets. may

<4-3>
In the first embodiment, in step S12 (measurement step) of the film manufacturing process, the MFR values of the recycled pellets at the first temperature TA and the second temperature TB were measured. may measure the MFR value of the regenerated pellets in one of the In this variation, when extruding the film 100 at either the first temperature TA or the second temperature TB, it is preferable to measure the MFR value of the recycled pellets at a temperature close to the temperature of the resin as it passes through the die. .

<4-4>
In the first embodiment, the recycled raw material containing the crushed film is used as the material forming the inner layer 30 of the film 100 . However, the layers of the film 100 that are made from recycled raw materials including shredded films are not limited to this. For example, recycled raw materials, including shredded film, may be used as the materials that make up the outer layers 10 , 20 of the film 100 . In this modification, in step S13 (determining step) of the film manufacturing process, a film to be manufactured from a plurality of product numbers A101 to A103 of the film 100 based on the fluidity of the recycled pellets and the fluidity of the outer layers 10 and 20. 100 product numbers are determined. Further, when the fluidity of the recycled pellets is extremely high, in other words, when the MFR value of the recycled pellets is extremely high, the recycled pellets may be used as the material forming the adhesive layer 40 . Since the recycled pellets contain the materials forming the outer layers 10 and 20, when the recycled pellets are used as the material forming the adhesive layer 40, the outer layers 10 and 20 and the inner layer 30 can be preferably bonded.

<4-5>
In the first embodiment described above, a laminated film having a plurality of layers was manufactured using a recycled raw material containing a crushed film. However, the structure of the film manufactured using the recycled raw material including the crushed film is not limited to this. For example, a monolayer film may be manufactured using recycled raw materials, including crushed film.

<4-6>
In each of the above-described embodiments, materials for forming the outer layers 10, 20 and the inner layer 30 of the film 100 can be arbitrarily selected.

In the first example, the adhesive layer 40 may be omitted, and the material forming the outer layers 10, 20 and the inner layer 30 of the film 100 may be the same type of resin material. The same kind of resin material is, for example, a polyester resin, a styrene resin, a polypropylene resin, a polyethylene resin, or a polyamide resin. Polyethylene-based resins are, for example, branched low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or high density polyethylene (HDPE). Polyamide-based resins are, for example, aliphatic polyamides or aromatic polyamides. In the case of the first example, it is preferable to use the recycled raw material as the material forming the inner layer 30 .

When the material forming the outer layers 10, 20 and the inner layer 30 of the film 100 is a polyester-based resin or a styrene-based resin, the film 100 is used, for example, as a heat-shrinkable film for PET bottles.

When the material forming the outer layers 10, 20 and the inner layer 30 of the film 100 is a polypropylene-based resin, the film 100 is used as a packaging film, for example.

When the material forming the outer layers 10, 20 and the inner layer 30 of the film 100 is a polyethylene resin, the film 100 is used as a backgrinding film or a dicing base film, for example.

When the material forming the outer layers 10, 20 and the inner layer 30 of the film 100 is a polyamide-based resin, the film 100 is used, for example, as a package for foods.

In the case of the first example, the material constituting the outer layers 10, 20 and the inner layer 30 may be exactly the same material. There may be differences such as For example, in consideration of the shrinkability and barrier performance of the film 100, resin materials with different product numbers or resin materials with different compositions may be used for the outer layers 10, 20 and the inner layer 30. FIG. In order to develop properties that depend on the surface condition of the film 100, such as heat-sealability, printability, slipperiness, and adhesion, an anti-blocking agent (AB agent) and Other resin species may be added. Further, in order to color the film 100, a coloring agent for resin (MB-COLOR) may be added to the materials forming the outer layers 10 and 20 in some cases.

In a second example, the adhesive layer 40 may be omitted, and the material forming the outer layers 10 and 20 of the film 100 and the material forming the inner layer 30 may be different. In the first specific example of the second example, the material forming the outer layers 10 and 20 of the film 100 is a polyethylene-based resin, and the material forming the inner layer 30 is a polypropylene-based resin. In this embodiment, the film 100 is used as a backgrinding film or a dicing substrate film. In the first specific example, it is preferable to use a recycled raw material as the material for forming the inner layer 30 .

In a second specific example of the second example, the material forming the outer layers 10, 20 of the film 100 is a cyclic olefin copolymer, and the material forming the inner layer 30 is a polypropylene resin. In a second specific example, the film 100 is used, for example, as a heat-shrinkable film for PET bottles. In the second specific example, it is preferable to use a recycled raw material as the material for forming the inner layer 30 .

In the third specific example of the second example, the material forming the outer layers 10 and 20 of the film 100 is a polyamide resin, and the material forming the inner layer 30 is an ethylene-vinyl alcohol copolymer. In the third specific example, the film 100 is used as a package for foodstuffs and the like. In the third specific example, it is preferable to use a recycled raw material as the material for forming the outer layers 10 and 20 . Since the polyamide-based resin and the ethylene-vinyl alcohol copolymer are not compatible with each other, when the recycled material of the film 100 having the layer structure of the third specific example is used as the material constituting the inner layer 30, the inner layer 30 becomes cloudy. In addition, since the inner layer 30 made of ethylene-vinyl alcohol copolymer is a layer that contributes to gas barrier performance, the inclusion of other resins reduces the barrier performance. Since the ethylene-vinyl alcohol copolymer is a reactive resin, aggregates (gelled substances) are generated when other resin species are mixed. From this point of view, in the third specific example, it is not preferable to use the recycled raw material as the material for forming the inner layer 30 .

In the fourth specific example of the second example, the material forming the outer layers 10 and 20 of the film 100 is a polyethylene-based resin, and the material forming the inner layer 30 is a polyamide-based resin. In the fourth specific example, the film 100 is used as a packaging material for food and the like. In the fourth specific example, it is preferable to use a recycled raw material as a material for forming the outer layers 10 and 20 .

<4-7>
In each of the above embodiments, MFR is used as an index for evaluating fluidity, but MVR (Melt Volume Rate) may be used as an index for evaluating fluidity.

S11: re-pelletizing step S12: measuring step S13: determining step S14: manufacturing step S15: manufacturing step

Claims (9)

a repelletizing step of producing recycled pellets by pelletizing a mixed material comprising recycled feedstock comprising crushed film and virgin feedstock of any layer of the film to be produced;
a measuring step of measuring the fluidity of the recycled pellets;
a determination step of determining a product number to be manufactured from a plurality of product numbers of the film based on the fluidity of the regenerated pellets;
and a production step of producing a film having the product number determined in the determination step, using the recycled pellets. 2. The method of manufacturing a film according to claim 1, wherein in said manufacturing step, a film having a product number determined in said determining step is manufactured using a film raw material obtained by mixing said recycled pellets and said virgin raw material. 3. The production of the film according to claim 2, wherein in the production step, the mixing ratio of the recycled pellets and the virgin raw material is determined based on the difference between the fluidity of the recycled pellets and the fluidity of the arbitrary layer. Method. 4. The film according to claim 3, wherein in the manufacturing step, the mixing ratio of the recycled pellets and the virgin raw material is determined so that the fluidity of the film raw material is within a predetermined range including the fluidity of the arbitrary layer. manufacturing method. In the manufacturing step,
The fluidity of the film raw material is
so as to fall within a first predetermined range that includes the fluidity of the arbitrary layer at the first temperature, and
5. The method of producing a film according to claim 4, wherein the mixing ratio of the regenerated pellets and the virgin raw material is determined so as to fall within a second predetermined range including fluidity of the arbitrary layer at the second temperature. In the determination step, the product number to be manufactured is determined from a plurality of product numbers of the film based on at least one of the optical properties, color appearance, purity, and shape of the recycled pellets in addition to the fluidity of the recycled pellets. A method for producing the film according to any one of claims 1 to 5. a measuring step of measuring the flowability of a mixed material containing recycled raw material containing crushed film and virgin raw material of any layer of the film to be manufactured;
a determination step of determining a product number to be manufactured from a plurality of product numbers of the film based on the fluidity of the mixed material;
and a production step of producing a film having the product number determined in the determination step, using the mixed material. In the determination step, the product number to be manufactured is determined from the plurality of product numbers of the film based on at least one of the optical properties, color appearance, purity, and shape of the mixed material in addition to the fluidity of the mixed material. The manufacturing method of the film of Claim 7. The method for producing a film according to any one of claims 1 to 8, wherein the crushed film is subjected to deinking treatment.

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