JP4839688B2 - Method for producing laminated film for packaging container - Google Patents

Description

The present invention relates to a method for producing a laminated film for a packaging container, and more specifically, is used for producing a packaging container suitable for transporting precision articles handled in a clean room, such as a hard disk. The present invention relates to a method for producing a laminated film.

  Conventionally, conveyance of precision articles handled in a clean room is performed as follows using two film containers heat-sealed on three sides. First, after storing the article in the first film container, the inside air is deaerated, the open part is heat sealed, and further, the whole is stored in the second film container, and then the inside air is deaerated. Heat seal the open area. Then, after transporting the article, the second film container is opened before being carried into a clean room or the like. As a result, the article can be carried into a clean room or the like in a state where it is stored in a clean container to which no dust is attached.

However, the above method has the following problems. That is, by performing the above-described storage operation of the article in an appropriate clean room, the inner and outer surfaces of the first and second film containers can be kept clean and the storage operation can be completed. It is necessary to perform the work of heat and heat sealing of the open portion twice, and the work cost is high.

In order to solve the above problems, a packaging clean film comprising a base material portion having a heat seal layer on the inner side and protective film layers laminated on both outer and inner surfaces of the base material portion has been proposed ( Patent Document 1).
JP 7-330020 A

  The above-described packaging clean film can be maintained in a clean state on both the inside and outside of the substrate portion by producing and winding it into a web in an appropriate clean room. In addition, the web-shaped raw film which comprises each layer is obtained by the T-die method.

  The packaging clean film is made as follows. That is, prepare a pair of web-shaped packaging clean films, peel off the protective film layer laminated on each inner surface, feed each other into the clean room, and flow the web on both sides After heat-seal along the direction and heat-seal along the width direction, cut in the width direction.

  However, in the case of the above-described film container using the T-die method, a protective film layer as a peeling film is provided on both the outer side and the inner side of the base material portion having the heat seal layer in order to clean the inner surface and the outer surface. In addition, it is uneconomical, and requires a large number of winders for peeling and winding the peeling film, resulting in a large facility. Further, when producing a clean film for web-like packaging, the inner and outer surfaces of the film are exposed to the outside air or come into contact with the roll, which requires a relatively advanced clean room.

The present invention has been made in view of the above circumstances, and its object is fewer amount of Hanare剥film, moreover, does not require and highly clean room at simple equipment, for inexpensive packaging container It is providing the manufacturing method of a laminated | multilayer film.

  As a result of various studies, the present inventor has obtained the following knowledge. That is, the laminated film obtained by the co-extrusion inflation method is obtained as a tube from the annular die, but is immediately wound around a roll and flattened. Therefore, since the above-mentioned laminated film is kept clean in a portion corresponding to the inner surface, the outermost layer is configured to be peelable so that it is extremely suitable as a laminated film for packaging containers.

The present invention has been completed based on the above findings, and the gist thereof is a method for producing a laminated film for a packaging container by processing a laminated film obtained by a co-extrusion inflation method. The laminated film is composed of two or more layers and is folded flat and formed into a strip shape . The outermost layer is made of a gas barrier resin and the innermost layer is made of a heat sealable resin (however, the inner layer adjacent to the outermost layer). Is composed of a gas barrier resin and an insoluble thermoplastic resin at the time of heat sealing), and in the above processing, the outermost layer near or both ends along the longitudinal direction of the laminated film is cut and the cutting line is cut. A stripping allowance formed by peeling processing with a constant width along each is formed , respectively, and the manufacturing method of the laminated film for packaging containers is provided.

  According to the present invention, it is possible to provide an inexpensive laminated film for packaging containers which requires only a small amount of peeling film and which does not require a high-quality clean room with simple equipment.

  Hereinafter, the present invention will be described in detail. The laminated film for packaging containers of the present invention (hereinafter simply abbreviated as “laminated film”) is obtained by processing a laminated film (raw fabric film) obtained by a coextrusion inflation method. A laminated film of an inflation method is obtained as a tube from an annular die, but is wound around a roll and flattened.

  The laminated film for packaging containers of the present invention is used as follows. The open part at one end is heat-sealed, and after storing the article, the air inside is degassed and the open part at the other end is heat-sealed. And after conveying articles | goods, before carrying in a clean room etc., an outermost layer is peeled. As a result, the article is carried into a clean room or the like in a state where it is stored in a clean container to which no dust is attached. In addition, it may be stored for a long period before being carried into a clean room or the like.

  Therefore, the laminated film for packaging containers according to the present invention has an innermost layer composed of a heat-sealable resin, and has a gas barrier resin layer in order to prevent air from entering after degassing. The difference between the laminated film according to the first gist of the present invention and the laminated film according to the second gist lies in the position of the layer composed of the gas barrier resin, and in the former case, it is configured to be peelable. The outermost layer is made of a gas barrier resin, and in the latter case, the outermost layer is made of another inexpensive thermoplastic resin. Moreover, in one of the preferable embodiments of the laminated film for packaging containers of the present invention, it is recommended to use a modified polyolefin (APO) and a permanent antistatic agent as described later. Furthermore, the outermost layer preferably contains an anti-blocking agent from the viewpoint of blocking resistance when the packaging bag is laminated and stored.

  Then, first, each said resin, permanent antistatic agent, and antiblocking agent which are used for the laminated | multilayer film for packaging containers of this invention are demonstrated.

  Examples of heat-sealable resins include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), and ethylene-methacrylate copolymer ( EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EAA), ethylene-ethyl methacrylate copolymer (EMAA), adhesiveness Examples thereof include polyethylene, ionomer resin, EVA saponified product, linear low density polyethylene (L-LDPE), and copolymers thereof.

  Linear low density polyethylene (L-LDPE) is a copolymer of ethylene and an α-olefin having 3 to 13 carbon atoms (ethylene content: 86 to 99.5 mol%), and is produced by a conventional high pressure method. It is a low to medium density polyethylene different from the LDPE produced. The structural difference between the high pressure method LDPE and LLDPE is that the former has a multi-branched molecular structure and the latter has a linear molecular structure. Examples of the α-olefin copolymerized with ethylene in the production of LLDPE include butene-1, pentene-1, hexene-1, octene-1, 4-methylpentene-1. These copolymers are carried out by a low-medium pressure method using a so-called Ziegler-Natta type catalyst or metallocene catalyst.

  Examples of the gas barrier resin include polyamide (PA), saponified ethylene-vinyl acetate copolymer (EVOH), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC). Among these, polyamide (PA) or ethylene-vinyl acetate copolymer saponified product (EVOH) is preferable, and polyamide (PA) is particularly preferable.

  In the present invention, as the polyamide, various polyamides obtained by polycondensation of (1) a lactam having three or more members, (2) a polymerizable ω-amino acid, and (3) a diamine and a dicarboxylic acid are used. I can do it.

  Specific examples of the lactam having 3 or more rings include ε-caprolactam, enantolactam, α-pyrrolidone, α-piperidone, and the like, and specific examples of the polymerizable ω-amino acid include 6-amino Examples include hexanoic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 9-aminononanoic acid.

  Specific examples of the diamine include hexamethylene diamine, nonamethylene diamine, undecamethylene diamine, dodecamethylene diamine, and metaxylylene diamine. Specific examples of the dicarboxylic acid include terephthalic acid and isophthalic acid. , Adipic acid, sebacic acid, dodecanedioic acid, glutaric acid and the like.

  Specific examples of polyamides include nylon 4, 6, 7, 8, 11, 12, 6 · 6, 6 · 10, 6 · 11, 6 · 12, 6T, 6/6 · 6, 6/12, 6 / Although 6T, 6I / 6T, etc. are mentioned, Nylon 6 is usually used.

  The modified polyolefin (APO) is produced by copolymerizing and / or graft-polymerizing an α, β-unsaturated carboxylic acid or a derivative thereof to a polyolefin mainly composed of an ethylene component and / or a propylene component.

  Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene-ethylacrylic acid copolymer. Examples thereof include a polymer and an ethylene-sodium acrylate copolymer.

  Examples of the α, β-unsaturated carboxylic acid or derivative thereof to be copolymerized include acrylic acid, methacrylic acid, methyl methacrylic acid, sodium acrylate, zinc acrylate, vinyl acetate, glycidyl methacrylate, and the like. It is contained in the range within 40 mol%. Examples of the copolymer-modified polyolefin include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-ethylacrylic acid copolymer, and an ethylene-sodium acrylate copolymer.

  Examples of the grafted α, β-unsaturated carboxylic acid or derivative thereof include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, acid anhydrides thereof, and esters of these acids. Is mentioned. Of these modifying compounds, maleic anhydride is particularly preferred. The graft amount is usually selected from the range of 0.01 to 25% by weight, preferably 0.05 to 1.5% by weight, based on the polyolefin.

  The grafting reaction is performed by melt-mixing a polyolefin and an α, β-unsaturated carboxylic acid or derivative thereof at a temperature of 150 to 300 ° C. according to a conventional method. In the grafting reaction, 0.001 to 0.05% by weight of an organic peroxide such as α, α'-bis-t-butylperoxy-p-diisopropylbenzene is blended in order to efficiently perform the reaction. Good.

  The permanent antistatic agent is a polymer type antistatic agent used by blending with a target resin and alloying, and many compounds have been proposed. For example, polymer type antistatic agents such as polyvinyl alcohol, polyether, polyether polyamide, polyester, polyester polyamide and the like can be mentioned.

  The anti-blocking agent can be composed of organic fine particles or inorganic fine particles. Examples of the anti-blocking agent composed of organic fine particles include polystyrene, polyethylene, polyamide, polyester, polyacrylic acid ester, polymethacrylic acid ester, epoxy resin, polyvinyl acetate, polyvinyl chloride, or a homopolymer or a copolymer. Examples thereof include fine particles that may contain a crosslinking agent. On the other hand, examples of the antiblocking agent composed of inorganic fine particles include talc, kaolin, silica, calcium carbonate, and glass powder. The average particle size of each antiblocking agent is usually about 1 to 10 μm. In addition, as the inorganic fine particles, a composition (master batch) previously blended with a resin may be used.

  Next, the layer structure of the laminated film according to the first aspect of the present invention will be described. This laminated film is composed of two or more layers, the outermost layer is made of a gas barrier resin, and the innermost layer is made of a heat sealable resin. However, the inner layer adjacent to the outermost layer is composed of a gas barrier resin and an insoluble thermoplastic resin during heat sealing. Specifically, as the resin constituting the outermost layer, a resin having a melting point higher than the melting point of the resin constituting the inner layer and the heat seal temperature may be used. The reason for this is to enable peeling between the outermost layer and the adjacent inner layer also by heat seal processing described later.

  As long as the above layer configuration conditions are satisfied, the constituent resin of each layer can be arbitrarily selected from the resins described above. However, in the present invention, the outermost layer is PA and the intermediate layer is LDPE from the viewpoint of cost and the like. A three-layer laminated film (PA / LDPE / LDPE and L-LDPE) in which the innermost layer is composed of a composition of LDPE and L-LDPE is recommended. In this case, the significance of using the composition of LDPE and L-LDPE for the innermost layer is as follows. That is, in the laminated film for packaging containers of the present invention, the innermost layers are heat-sealed and integrated, but by adding L-LDPE to inexpensive LDPE, the heat seal strength can be increased. is there. The compounding quantity of L-LDPE is 0.5-3 weight times normally as a ratio with respect to LDPE, Preferably it is 1-2 weight times.

  Moreover, the thickness of each layer in said layer structure is as follows. That is, the thickness of the outermost layer (release layer and gas barrier layer) is usually 5 to 50 μm, preferably 25 to 45 μm, and the thickness of the intermediate layer is usually 5 to 100 μm, preferably 10 to 70 μm, and the innermost layer (heat seal) The thickness of the layer) is usually 20 to 100 μm, preferably 30 to 70 μm. Incidentally, the width of the laminated film (the width of the laminated film that is obtained as a tube from an annular die and then completely flattened by being rolled up) is appropriately selected depending on the size of the article to be stored and the like. Usually, it is 200 to 600 mm.

  In a preferred embodiment of the present invention, a permanent antistatic agent is blended in at least the constituent resin of the innermost layer, and the blending amount is usually 5 to 25% by weight, preferably 10 to 20% by weight per resin. %. In addition, an anti-blocking agent is blended in at least the constituent resin of the outermost layer, and the blending amount is usually 100 to 10,000 ppm, preferably 1,000 to 5,000 ppm as a ratio per resin.

  Next, the layer structure of the laminated film according to the second aspect of the present invention will be described. This laminated film is composed of three or more layers, the outermost layer is made of a thermoplastic resin other than the gas barrier resin, the intermediate layer is made of a gas barrier resin, and the innermost layer is made of a heat sealable resin. . However, for the same reason as in the case of the laminated film according to the first aspect, the outermost layer adjacent to the intermediate layer is composed of a gas barrier resin and an insoluble thermoplastic resin during heat sealing.

  As long as the above layer configuration conditions are satisfied, the constituent resin of each layer can be arbitrarily selected from the resins described above. However, in the present invention, from the viewpoint of cost and the like, the outermost layer is LDPE, and the intermediate outer layer is PA. A four-layer film (LDPE / PA / APO / LDPE and L-LDPE) in which the intermediate inner layer is APO and the innermost layer is composed of the above-mentioned composition of LDPE and L-LDPE is recommended.

  Moreover, the thickness of each layer in said layer structure is as follows. That is, the thickness of the outermost layer (release layer) is usually 5 to 100 μm, preferably 35 to 70 μm, and the thickness of the intermediate outer layer (gas barrier layer) is usually 5 to 50 μm, preferably 10 to 30 μm. The thickness of the layer) is usually 2 to 30 μm, preferably 5 to 15 μm, and the thickness of the innermost layer (heat seal layer) is usually 20 to 100 μm, preferably 30 to 70 μm. The width of the laminated film is the same as described above.

  Next, the structural features of the laminated film for packaging containers of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing an example of a preferred embodiment of the laminated film according to the first aspect of the present invention, with the layer structure broken. FIG. 1 shows an example of a two-layer laminated film having the simplest layer structure for the sake of simplification of the drawing.

  The laminated film (1) according to the first gist of the present invention is a strip formed by cutting the outermost layer (11) at both ends in the longitudinal direction or in the vicinity of both ends, and peeling-processing with a constant width along the cutting line. The stripping allowances (13) and (13) are respectively formed, and the outermost layer (11) is configured to be peelable using the above-described stripping allowances (13) and (13). And in a preferable aspect, in the position corresponding to the inner side of the left and right stripping allowances (13) and (13), the innermost layer (12) has a strip of heat seal portion (15) along the stripping allowance, (15) are provided.

  In the figure, reference numeral (14) is a heating part, and (16) is a non-peeling part, and in FIG. 1, peeling allowances (13) and (13) are turned for easy understanding. Although it is drawn as it is, it is actually in close contact with the innermost layer (12) in the same manner as the non-peeling portion (16).

  The effects of the heat seal portions (15) and (15) are as follows. That is, the outermost layer made of the gas barrier resin (11) is cut as described above to form the peeling allowances (13) and (13), and the peeling allowances (13) , (13) is once peeled, even though it is in close contact with the innermost layer (12). As a result, the gas barrier property due to (11) is deteriorated in the outermost layer in the vicinity of both ends in the longitudinal direction of the innermost layer (12). Therefore, when the article is stored for a long period of time using the laminated film for packaging containers of the present invention, that is, the open portion at one end of the laminated film for packaging containers is heat-sealed, and after storing the article, the air inside When air is deaerated and the open part at the other end is heat-sealed and stored for a long period of time, air may enter the packaging container. Therefore, a single heat seal portion (15), (15) is provided in the innermost layer (12) at the position corresponding to the inner side of the stripped margins (13), (13) on the left and right along the stripped margin. Thereby, the gas barrier property of the innermost layer (12) can be ensured within the range of the outermost layer (11) which is not peeled.

  Therefore, in the above aspect, it is preferable that the outermost layer is provided with a non-peeling portion (16) in (11) at a position corresponding to the outside of each heat seal portion (15), (15).

  In the illustrated example, the stripping allowances (13) and (13) are formed with a constant width including both end edges by cutting both end edges of the outermost layer (11), but cutting near both ends. Thus, it can be formed with a constant width not including both end edges. Moreover, a non-peeling process part (16) is arbitrary and the peeling allowance (13) and the heating part (14) may adjoin. The width of the peeling allowance (13) is about 5 to 10% of the width of the laminated film (in the case of a laminated film having a width of 500 mm, it is 25 to 50 mm. Incidentally, the width of the heating section (14) (the width of the heat sealer) Is equivalent to 5 to 2 mm.

  On the other hand, the laminated film according to the second gist of the present invention is the above laminated film (1) according to the first gist, except that there is no single heat seal part (15), (15). This is the same as the laminated film (1) according to the first aspect.

  Next, the manufacturing method of the laminated | multilayer film for packaging containers of this invention is demonstrated. First, in the present invention, a laminated film is obtained by a coextrusion inflation method. As the inflation method, a known method (air cooling method) can be employed in which the film extruded from the die is guided above the die and cooled by blowing cooling air. Usually, an air ring that blows cooling air is arranged above the annular die, and an equipment in which an an inner plate and a winding roll are sequentially arranged above the air ring is used. The raw material resin is co-extruded so that stretching does not occur substantially, and is cooled by passing between air rings, and then the laminated film cylindrical body is supplied to the take-up roll through the inner plate and folded. Take up as.

  Next, in the present invention, the laminated film (raw film) obtained by the coextrusion inflation method is processed to form a peeling allowance, and a predetermined heat seal is performed as necessary.

  FIG. 2 is an explanatory view of an example of a laminated film manufacturing process (a laminated film processing process obtained by a coextrusion inflation method) according to the first aspect of the present invention, and FIG. 3 is shown in FIG. FIG. 4 is an explanatory view of a main part of the ear cleaving device shown in FIG. 3.

  The original film (3) delivered from the original film roll (2) repeats running and stopping, while the ear tear device (4), side seal device (5), bottom seal device (6), cutting device ( 7) are sequentially processed. Reference numeral (8) is a guide roll, and (9) is a drive pinch roll (rubber roll).

  The ear cleaving device (4) includes left and right frames (41) and (41) arranged in parallel along the transfer direction of the original film (3), and guide rails (42) installed on the frame, Support blocks (43) and (43), which are slidably attached to both ends of the guide rail, and an L-shaped release plate (44) mounted horizontally on the upper side of the support block. ) And a cutting blade (45) having a blade edge exposed at the corner of the peeling plate and fixed by a presser plate (46). The positions of the peeling plate (44) and the cutting blade (45) with respect to the original film (3) are adjusted by the fixing position of the support block (43), and the ear film of the original film (3) is processed as follows. To be done.

  That is, by inserting the tip of the release plate (44) between the outermost layer (11) and the innermost layer (12) along both ends of the original film (3) and running the original film (3), Both ends of the outermost layer (11) are cut while peeling the outermost layer (11) and the innermost layer (12). And in order to prevent accidental cutting of both ends of the innermost layer (12), the outer edge of the front end portion of the peeling plate (44) is formed so that the peeling distance between the outer layer (11) and the innermost layer (12) is increased. The shape is slightly inclined upward.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. In the following examples, the following materials were used.

(1) Low density polyethylene (LDPE):
“Novatec LC560” manufactured by Nippon Polyethylene Co., Ltd. (MFR: 3.5 g / 10 min, density: 0.926 g / cm ³ )

(2) Linear low density polyethylene (L-LDPE):
“Harmolex NF464N” manufactured by Nippon Polyethylene Co., Ltd. (MFR: 2.0 g / 10 min, density: 0.918 g / cm ³ )

(3) Polyamide:
“Novamid 2430J” (6/6/6 copolymer nylon) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (MFR: 4.5 g / 10 min, density: 1.13 g / cm ³ )

(5) Permanent antistatic agent:
“Pelestat 230” (polyether type polymer antistatic agent) manufactured by Sanyo Chemical Industries

(6) Anti-blocking agent:
“2420AMT” manufactured by Mitsubishi Engineering Plastics (6/6/6 copolymer nylon composition having a silica content of 15% by weight) (MFR: 3.5 g / 10 min, density: 1.28 g / cm ³ )

Example 1:
A laminated film having a layer configuration shown in Table 1 and having a thickness of 0.1 mm and a width of 450 mm was obtained by air-cooling using a co-extrusion inflation method using a three-layer co-extrusion annular die. The die temperature is 240 ° C., the air cooling temperature is 15 to 30 ° C., and the winding speed is 7.2 m / min. It was.

  Next, a laminated film for a packaging container having a thickness of 0.1 mm, a width of 450 mm, and a length of 450 mm was obtained by the manufacturing process shown in FIG. 2 provided with the ear cleaving device shown in FIGS. 3 and 4. The temperatures of the side seal and the bottom seal were both 220 ° C. The width of the peeling allowance (13) was 35 mm, the width of the heat seal part (15) was 20 mm, and the width of the non-peeling part (16) was 15 mm. The peeling allowance (13) was in a state of being in close contact with the intermediate layer, but could be easily turned over, and the outer layer could be easily peeled off using the peeling allowance (13).

Example 2:
In Example 1, a packaging container was used in the same manner as in Example 1 except that a polyamide (79% by weight), a permanent antistatic agent (15% by weight), and an antiblocking agent (6%) were used as the outer layer. A laminated film for use was obtained. As in Example 1, the peeling allowance (13) is in close contact with the intermediate layer, but can be easily turned over, and the outer layer can be easily peeled off using the peeling allowance (13). It was.

The typical perspective view which fractures | ruptures and shows the layer structure of an example of the preferable aspect of the laminated | multilayer film of this invention Explanatory drawing of an example of the manufacturing process (processing process of the laminated | multilayer film obtained by the coextrusion inflation method) of the laminated | multilayer film of this invention Plane explanatory drawing of the ear tearing device used in the manufacturing process shown in FIG. Explanatory drawing of the principal part of the ear tear device shown in FIG.

Explanation of symbols

1: Laminated film for packaging container 11: Outermost layer 12: Innermost layer 13: Peeling margin 14: Heating part 15: Heat sealing part 16: Non-peeling part 2: Raw film roll 3: Raw film 4: Ear tear Device 41: Frame 42: Guide rail 43: Support block 44: Release plate 45: Cutting blade 46: Holding plate 5: Side seal device 6: Bottom seal device 7: Cutting device 8: Guide roll 9: Pinch roll

Claims (3)

A method for producing a laminated film for a packaging container by processing a laminated film obtained by the coextrusion inflation method, wherein the laminated film is composed of two or more layers and is flatly folded to be formed into a strip shape. The outer layer is composed of a gas barrier resin, and the innermost layer is composed of a heat sealable resin (however, the inner layer adjacent to the outermost layer is composed of a gas barrier resin and an insoluble thermoplastic resin during heat sealing. ), in the processing described above to form a peeling generations of Article formed by peeling process with a constant width both edges or ends outermost vicinity along the longitudinal direction along the cut and the cutting line of the laminate film respectively A method for producing a laminated film for a packaging container. Method for producing a packaging container stacked film as claimed heat-sealed portion of the Article along peeling off allowance in the innermost layer to set Keru claim 1 respectively, in a position corresponding to the inside of the Article of peeling-off allowance of the left and right. The laminated film consists of three layers, the outermost layer is made of polyamide, the intermediate layer is made of low density polyethylene, the innermost layer is made of a composition of low density polyethylene and linear low density polyethylene, and the intermediate layer and innermost layer are made of resin. The manufacturing method of the laminated | multilayer film for packaging containers of Claim 1 or 2 by which permanent antistatic agent is mix | blended.

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