JPWO2017217414A1 - Method for producing a synthetic resin film cover - Google Patents

Abstract

(1) The width of the space required for construction of the production line can be greatly reduced compared to the conventional case. (2) When the manufactured cover is applied to the tray, Adsorption of dust or the like on the surface facing the stored food is prevented as much as possible. (3) Even if a relatively thin film is used, the so-called waist strength necessary for proper conveyance is obtained. (4) Provided is a method for producing a synthetic resin cover that does not require a relatively complicated folding step after production. A preparation step of preparing the elongated tubular synthetic resin film (20a), and after the preparation step, at least one side portion of the tubular synthetic resin film (20) is forced inward in the width direction to form a bellows-like folded portion (20a). A folding step, and after the folding step, a cutting step for cutting the radially inner end (20a-1) of the folding portion to form a laminated portion, and after the folding step, the folding portion is spaced apart in the longitudinal direction. And a welding step of forming welding lines (6a, 6b) by welding. [Selection] Figure 5

Description

  In the present invention, there is a laminated portion in which both sides are folded from the front surface to the back surface, and a non-folded portion and a folded portion are laminated, and an unfolded portion and a folded portion are provided at both longitudinal ends of the laminated portion. The present invention relates to a method of manufacturing a cover made of a synthetic resin film in which welded weld lines are disposed.

  For example, as a tray for storing and transporting food products such as confectionery bread, precision products, industrial products such as electronic component bases, or containers containing chemicals, a box shape with a rectangular parallelepiped shape as a whole and an open top surface Trays are widely used in practical use. Usually, the upper surface of the tray is formed with flanges projecting outward from the upper ends of both side walls and both end walls. Further, as disclosed in Patent Document 1 below, a tray cover made of a synthetic resin film that covers the upper surface of a tray that stores foods and the like has also been proposed and put into practical use. This tray cover made of synthetic resin film is provided with a laminated portion in which both sides are folded from the front surface to the back surface and a non-folded portion and a folded portion are laminated, and non-folded at both longitudinal ends of the laminated portion. The welding line which welded the folding part and the folding part is arrange | positioned. In such a cover, the pocket-shaped portion defined inside the welding line provided on both sides of one end of the cover is locked to the flange corners on both sides of the upper surface of the tray, and then the cover is placed on the tray. The pocket-shaped portion defined inside the welding line disposed on both sides of the other end of the cover is engaged with the corners of the flange on the other end of the upper surface of the tray. To cover the open top surface of the tray.

  The cover in the form as described above is conventionally unfolded by folding from the front surface to the back surface on both sides of the synthetic resin film extended in a rectangular shape as disclosed in Patent Document 1 below. And a folded part are laminated to form a laminated part, and then a non-folded part and a folded part are welded at both longitudinal ends of the laminated part to provide a welding line.

EP1642841A2 publication

  Thus, in the conventional method for producing the synthetic resin cover as described above, (1) a folding line and a welding process are carried out while the synthetic resin film is conveyed in a strip-like state, so that a production line is constructed. (2) Dust or the like is adsorbed on the front and back surfaces of the synthetic resin film that is triboelectrically charged, and in particular, food, industrial products, or chemicals stored in the trays described above are stored. Dust adsorbed on the back of the container facing the container creates hygiene problems for foodstuffs, malfunctions for industrial products, etc., and containers for chemicals in the container. (3) It is necessary to use a relatively thick synthetic resin film as a raw material in order to ensure ease of transport. It is extremely difficult to transport a strip-shaped synthetic resin film that is extremely thin and therefore has a very low waist strength as required), and the manufacturing cost is relatively expensive. (4) Ships many manufactured covers In order to reduce the size in the width direction of the shipment, it is desired to fold the cover around the central longitudinal axis, and therefore, it is necessary to perform a relatively complicated folding process after manufacturing. There are problems to be solved.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide a new and improved method in which the above-mentioned problems existing in conventional methods for producing a synthetic resin cover are solved. It is to be.

  As a result of diligent study, the present inventors use a long tube-shaped synthetic resin film as a raw material instead of a strip-shaped synthetic resin film, and perform the necessary processing on the tube-shaped synthetic resin film to produce a cover. It has been found that the above main technical problem can be achieved.

That is, according to the present invention, as a method for achieving the main technical problem, there is a laminated portion in which both sides are folded from the front surface to the back surface, and the unfolded portion and the folded portion are laminated, and the laminated portion In a method of manufacturing a cover made of a synthetic resin film in which welding lines in which the unfolded portion and the folded portion are welded are disposed at both longitudinal ends of
A preparation step of preparing an elongated tubular synthetic resin film;
After the preparation step, a folding step of forcing at least one side portion of the tubular synthetic resin film to the inside in the width direction to form a bellows-like folding portion;
After the folding step, a cutting step of cutting the radially inner end of the folded portion to form the laminated portion;
After the folding step, a welding step of forming the welding line by welding the folded portion with an interval in the longitudinal direction;
Is provided.

  Preferably, in the folding step, both side portions of the tubular synthetic resin film are forced to the inside in the width direction to form bellows-like folded portions on both side portions of the tubular synthetic resin film, and in the cutting step, Cutting the radially inner end of only the folded portion present on one side of the tubular synthetic resin film, and in the welding step, only the folded portion existing on the one side of the tubular synthetic resin film is elongated. The folds are welded at intervals in the direction. In the welding step, an upstream welding line in the cover synthetic resin film located on the downstream side and a downstream welding line in the cover synthetic resin film located on the upstream side are simultaneously formed, and after the welding step, It is preferable to include a separation step of cutting the elongated tubular synthetic resin film over the entire width direction between the upstream welding line and the downstream welding line.

  According to the method of the present invention, (1) space required for construction of a production line because a desired process is performed while transporting a tube-shaped synthetic resin film whose width dimension is considerably smaller than the width of a cover to be produced. (2) When the manufactured cover is applied to the tray, the surface of the cover that faces the food items stored in the tray is Since it is defined not by the outer surface exposed to the outside of the tube-shaped synthetic resin film but by the inner surface, dust and the like are prevented from being adsorbed to the surface as much as possible. (3) Transporting the tube-shaped synthetic resin film Therefore, even if a film having at least half the thickness is used compared with the case of transporting a belt-like film, the so-called waist strength necessary for proper transportation can be obtained, and the manufacturing cost can be considerably reduced. Possible, (4) the cover to be produced in a folded form about its longitudinal central axis, there is no need perform relatively complicated folding process after manufacture.

The slope view which shows the typical example of the synthetic resin covers manufactured by suitable embodiment of the method of this invention. The slope view which shows the typical example of the tray which is an example of the container to which the cover shown in FIG. 1 is applied. The simplification figure which shows suitable embodiment of the preparation process and folding process in the method of this invention. The slope view which shows the folding tool currently used for the folding process shown in FIG. The simplification figure which shows suitable embodiment of the cutting process in the method of this invention, a welding process, and a isolation | separation process. The slope view (a) and cross-sectional view (b) which show the cover manufactured by suitable embodiment of the method of this invention in the state manufactured. The slope view (a) and cross-sectional view (b) which show the cover manufactured by the modified embodiment of the method of this invention in the manufactured state. The slope view which shows the modification of the synthetic resin covers manufactured by suitable embodiment of the method of this invention.

  The preferred embodiments of the method of the present invention for producing a synthetic resin cover will be described below in more detail with reference to the accompanying drawings.

  FIG. 1 shows a typical example of a synthetic resin cover manufactured by the method of the present invention. The cover denoted as a whole by number 2 is formed from a suitable synthetic resin film such as a polyethylene film having a thickness of about 0.020 to 0.080 mm, and laminated portions 4a and 4b are present on both sides thereof. Each of the stacked portions 4a and 4b is folded with both side end portions of the required width direction dimension from the front surface to the back surface, and the unfolded portions 4a-1 and 4b-1 and the folded portions 4a-2 and 4b-2 are stacked. Is formed. The main part 6 located between the laminated parts 4a and 4b is defined by a single layer film.

  The welding lines 6a and 6b formed by welding the unfolded parts 4a-1 and 4b-1 and the folded parts 4a-2 and 4b-2 are arranged at both longitudinal ends of the stacked parts 4a and 4b. It is installed. Each of the welding lines 6a and 6b may be a line having an appropriate shape extending in the width direction through the stacked portions 4a and 4b. In the illustrated example, the width-direction inner arc line 6a-1 that is convex inward in the longitudinal direction. 6b-1 and the widthwise outer arcuate lines 6a-2 and 6b-2 that are convex outward in the longitudinal direction. Pocket-like portions 8a and 8b are defined on the inner side in the longitudinal direction of each of the welding lines 6a and 6b.

  FIG. 2 shows a tray as an example of a container to which a cover 2 as shown in FIG. 1 is applied. The tray denoted as a whole by the number 10, which can be formed from an appropriate synthetic resin such as polypropylene or polyethylene by the injection molding method, is a box shape having a rectangular parallelepiped shape as a whole and an open upper surface. A rectangular flange 16 projecting outward from the upper ends of both side walls 12 and both end walls 14 is formed on the open upper surface of the tray 10. In the illustrated tray, the outer surfaces of the lower end portions of the side walls 12 and the both end walls 14 are somewhat retracted from the outer surface of the main portion, and the outer shape of the lower end portion of the tray 10 is set somewhat smaller than the main portion outer shape. . An L-shaped flange 18 is formed on the outer surface of the four corners of the tray 10 so as to project outward from directly above the outer surface of the lower end portion whose outer shape is reduced. When stacking the trays 10, the lower ends of the upper trays 10, that is, the lower ends of the side walls 12 and both end walls 14, which are somewhat retracted, are immersed in the lower tray 10, and Each L-shaped flange 18 is placed on the upper surface of the corner portion of the rectangular flange 16 formed on the upper surface of the lower tray 10. Since such a tray 10 itself is a well-known form, the detailed description is abbreviate | omitted in this specification.

  When the cover 2 as shown in FIG. 1 is applied to the tray 10 as shown in FIG. 2, the pocket portions 8 a and 8 b defined on both sides of one end of the cover 2 are formed on the upper surface of the tray 10. The cover 2 is extended along the upper surface of the tray 10 and the pocket-shaped portions 8a and 8b defined on both sides of the other end of the cover 10 The rectangular flange 16 formed on the upper surface is engaged with both sides of the other end, and thus the cover 2 is attached to the tray 10 and the open upper surface of the tray 10 is covered with the cover 2. In FIG. 2, the cover 2 mounted on the tray 10 as described above is illustrated by a two-dot chain line.

  Next, a preferred embodiment of the method of the present invention for manufacturing the cover 2 as described above will be described in detail.

Preparation Step In the method of the present invention, it is important to prepare a tube-shaped synthetic resin film, not a sheet-shaped synthetic resin film. Referring to FIG. 3, in the illustrated embodiment, a sufficiently long tube-shaped synthetic resin film 20 is wound into a flat form and mounted on the feed roller 22.

The synthetic resin film 20 unwound from the folding device delivery roller 22 is fed into the folding device 24. The folding device 24 includes a carry-in roller pair 26, a folding device 28, and a carry-out roller pair 30. In the illustrated embodiment, the carry-in roller pair 26 and the carry-out roller pair 30 are arranged at a predetermined distance apart in the vertical direction, and the folding device 28 is disposed between the carry-in roller pair 26 and the carry-out roller pair 30. Has been. Referring to FIG. 4 together with FIG. 3, the folding device 28 that can be formed by appropriately deforming and joining a hard cardboard or a thin metal plate is open at the upstream end (upper end) and downstream end (lower end) as a whole. The front wall 32 and the rear wall 34 are inclined toward the downstream and the front, respectively, and the distance between the front wall 32 and the rear wall 34 gradually decreases toward the downstream. I'm hurt. The one side wall 36 and the other side wall 38 are flat at the upstream end, but are inclined forward in the downstream direction from the upstream end to the downstream end and inclined inward in the width direction toward the downstream. It is folded by a fold line 40 that extends backward and a fold line 42 that inclines backward toward the downstream and extends inward in the width direction toward the downstream, and a substantially X-shaped opening is defined at the downstream end.

The synthetic resin film 20 unwound from the folding process feed roll 22 is sandwiched between the carry-in roller pair 26, and then sandwiched between the carry-out roller pair 30 through the folding device 28. At this time, as clearly understood by referring to FIG. 3, the synthetic resin film 20 is filled with compressed air of a required pressure and sealed between the carry-in roller pair 26 and the carry-out roller pair 30. . When the synthetic resin film 20 is set in the folding device 24 in this manner, the sending roller 20, the carry-in roller pair 26, and the carry-out roller pair 30 are rotationally driven in the directions indicated by the arrows, and the synthetic resin film 20 is placed in the folder 28. Transported through. While the synthetic resin film 20 is conveyed through the folding device 28, the cross-sectional shape of the synthetic resin film 20 is gradually deformed into a shape corresponding to the inner cross-sectional shape of the folding device 28 by the action of compressed air. That is, both side portions of the synthetic resin film 20 are forced to the inner side in the width direction, the cross-sectional shape of the synthetic resin film 20 is deformed into a shape corresponding to the cross-sectional shape of the downstream end of the folding device 28, and bellows-like folded portions are formed on both side portions. 20a and 20b are formed. The synthetic resin film 20 unloaded from the unloading roller pair 30 can be wound around an appropriate winding roller (not shown). If desired, the synthetic resin film 20 unloaded from the unloading roller pair 30 can be directly conveyed to a cutting, welding, and separating apparatus described later.

Cutting / welding / separating apparatus As described above, the synthetic resin film 20 having the bellows-like folded portions 20a and 20b formed on both sides thereof is once wound on a winding roller (not shown) or after the folding It is fed directly from the carry-out roller pair 30 of the device 24 to the cutting / welding / separating device 44 shown in FIG. The illustrated cutting / welding / separating device 44 includes a carry-in roller pair 46, a cutting tool 48, a welding means 50, a carry-out roller pair 52, and a separating means 54. The carry-in roller pair 46 and the carry-out roller pair 52 are intermittently rotated in the direction indicated by the arrow, and the synthetic resin film 20 is repeatedly intermittently conveyed by the length in the longitudinal direction of the cover 2 in the direction indicated by the arrow.

Cutting tool 48 according to the embodiment of the cutting step shown is constituted by a plate-like piece having a cutting blade 56 provided on the bottom edge of the rectangular notches, opposite one side of the folded portion 20a of the synthetic resin film 20 The cutting blade 56 is positioned and faces the inner edge 20a-1 in the radial direction of the folding portion 20a. Therefore, while the synthetic resin film 20 is conveyed in the direction indicated by the arrow, the cutting edge 56 cuts the radially inner edge 20a-1 of the folded portion 20a, thereby laminating the unfolded portion and the folded portion. The two laminated portions of the upper laminated portion, the folded portion, and the lower laminated portion in which the non-folded portion are laminated are formed (the two laminated portions are the laminated portions 4a of the cover 2). And 4b).

The welding means 50 shown in the welding process is composed of the above two laminated layers formed on the upper welding block 58 and the lower welding block 60 disposed above and below the synthetic resin film 20 and the folding portion 20 a of the synthetic resin film 20. It includes an intermediate table board 62 positioned between the sections. On the lower surface of the upper welding block 58, heating welding ridges (not shown) corresponding to the upstream welding line 6a in the previous cover and the downstream welding line 6a in the next cover are formed. Heat welding ridges (not shown) corresponding to the upstream welding line 6b in the previous cover and the downstream welding line 6b in the next cover are formed on the upper surface of the lower welding block. While the conveyance of the synthetic resin film 20 is interrupted, the upper welding block 58 is lowered and pressed against the upper surface of the intermediate table board 62 with the upper laminated portion in the synthetic resin film 20 interposed therebetween, and the lower welding is performed. The block 60 is raised and pressed against the lower surface of the intermediate table board 62 with the lower laminated portion of the synthetic resin film 20 interposed therebetween, and thus the unfolded portion and the folded portion of the upper laminated portion of the synthetic resin film 20 are formed. Two adjacent welding lines 6a are formed by welding, and the folded portion and the unfolded portion of the lower laminated portion of the synthetic resin film 20 are welded to form two adjacent welding lines 6b. The Since the intermediate table board 62 exists between the upper laminated portion and the lower laminated portion in the synthetic resin film 20, the upper laminated portion and the lower laminated portion are not welded. Next, the upper welding block 58 is raised to the original position and the lower welding block 60 is lowered to the original position, and thereafter, the synthetic resin film 20 is intermittently conveyed.

Separation means 54 disposed on the downstream side of the separation process carry-out roller pair 52 has an upper cutting blade 64 and a lower cutting blade 66 that cooperate with each other. While the conveyance of the synthetic resin film 20 is interrupted, the upper cutting blade 64 is lowered and the lower cutting blade 66 is raised, for the welding lines 6a and 6b for the downstream cover and the upstream cover. The synthetic resin film 20 is cut across the entire width direction between the welding lines 6 a and 6 b, and thus one completed cover 2 is separated from the synthetic resin film 20. Next, the upper cutting blade 64 is raised and returned to the original position, and the lower cutting blade 66 is lowered and returned to the original position, and thereafter, the synthetic resin film 20 is intermittently conveyed. FIGS. 6A and 6B are a perspective view and a cross-sectional view showing the cover 2 manufactured as described above with an enlarged folding direction gap for easy understanding.

  The manufactured cover 2 can be packaged and shipped in a state where it is separated from the synthetic resin film 20, that is, as shown in FIGS. 6a and 6b. When the cover 2 is used, the folded portion 20b remaining without being cut may be opened and the laminated portion 4-1 and the laminated portion 4-2 may be spread so as to be positioned on both sides.

  According to the method of the present invention as described above, (1) since a necessary process is performed while transporting the tube-shaped synthetic resin film 20, it is possible to construct a production line as compared with the case of transporting the sheet-shaped synthetic resin film. The width dimension of the required space can be greatly reduced. (2) When the cover 2 in a completed and shipped state is applied to the tray 10, the food items stored in the tray 10 in the cover 2 The surface facing the container containing the industrial product or chemical is the inner surface that is not exposed to the outside. Therefore, the food product stored in the tray 10 in the cover 2 at the time of manufacturing or shipping, As much as possible, dust or the like is prevented from adhering to the surface facing the container containing the product or chemical, and (3) it is made flat when manufactured (thus being laminated in two layers). The tube-shaped synthetic resin film 20 (in the form) is conveyed, so that even if a relatively thin synthetic resin film is used, a so-called waist strength sufficient for conveyance can be obtained, and the raw material cost is considerably reduced. (4) Since the cover 2 is completed in a form folded into a required form, it is not necessary to perform a relatively complicated folding process in order to make the cover 2 compact at the time of shipment.

  The preferred embodiments of the method of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to such embodiments, and various modifications and changes can be made without departing from the scope of the present invention. Correction is possible. For example, in the above-described embodiment, both sides of the tubular synthetic resin film 20 are folded in the folding step to form the bellows-like folded portions 20a and 20b on both sides, but if desired, the tubular synthetic resin film It is also possible to fold only one side of 20 and form a bellows-like fold 20a only on one side (no bellows-like fold 20b). FIGS. 7a and 7b are a perspective view and a cross-sectional view showing the cover 2 formed in this manner with an enlarged folding direction gap for easy understanding.

  Further, the cover manufactured by the method of the present invention is not limited to the cover that covers the upper surface of the tray as described above in which the flange is provided at the upper end, and is a tray, a rectangular parallelepiped, or a cube that does not have a flange at the upper end It can also be used to cover the top surface of a storage container or the like in shape. In the case of a cover applied to a tray, a rectangular parallelepiped or a cubic storage container having no flange at the upper end, the welding lines 6a and 6b are connected to the inner side in the longitudinal direction 6a- 1 and 6b-1 and the widthwise outer arcuate lines 6a-2 and 6b-2 that are convex outward in the longitudinal direction are connected to each other, as shown in FIG. A and 6'b are inclined linearly outward from the longitudinal edge toward the inside in the longitudinal direction and extend linearly, and the inclination angle α with respect to the longitudinal direction is 45 degrees or more, particularly about 45 to 65 degrees. Is preferable. When the inclination angle α is 45 degrees or more, particularly about 45 to 65 degrees, when the cover is attached to the container, the laminated portions 4′a and 4′b of the cover are placed on the outer peripheral surface of the tray or the storage container. Forced in the approaching direction, it is possible to prevent the cover from being detached from the tray or the storage container due to wind or the like as much as possible.

2: Cover 4a: Laminating part 4b: Laminating part 6a: Welding line 6b: Welding line 10: Tray 20: Tubular synthetic resin film 20a: Bellows-like folding part 20b: Bellows-like folding part 24: Folding device 28: Folding device 44 : Cutting / welding / separating device 48: Cutting tool 50: Welding means 54: Separating means

The present invention has been made in view of the above circumstances, the principal object is provided above problems existing in the conventional process for producing a synthetic resin cover is resolved, a new and improved method It is to be.

The longitudinal ends of each of the stacked portions 4a and 4b (the “ longitudinal ends of each of the stacked portions 4a and 4b” are not intermediate portions in the longitudinal direction of each of the stacked portions 4a and 4b, ie, in the direction of being elongated. 2, which are portions corresponding to each of the four corners of the rectangular flange 16 of the tray 10 illustrated in FIG. 2) , and the unfolded portions 4 a-1 and 4 b- 1 and welding lines 6a and 6b formed by welding the folded portions 4a-2 and 4b-2 are disposed. Each of the welding lines 6a and 6b may be a line having an appropriate shape extending in the width direction through the stacked portions 4a and 4b. In the illustrated example, the width-direction inner arc line 6a-1 that is convex inward in the longitudinal direction. 6b-1 and the widthwise outer arcuate lines 6a-2 and 6b-2 that are convex outward in the longitudinal direction. Pocket-like portions 8a and 8b are defined on the inner side in the longitudinal direction of each of the welding lines 6a and 6b.

Claims (3)

Folded from the front side to the back side on both sides, there is a laminated part in which the unfolded part and the folded part are laminated, and the welded part in which the unfolded part and the folded part are welded to both ends in the longitudinal direction of the laminated part In the method of manufacturing the synthetic resin film cover where the line is arranged,
A preparation step of preparing an elongated tubular synthetic resin film;
After the preparation step, a folding step of forcing at least one side portion of the tubular synthetic resin film to the inside in the width direction to form a bellows-like folding portion;
After the folding step, a cutting step of cutting the radially inner end of the folded portion to form the laminated portion;
After the folding step, a welding step of forming the welding line by welding the folded portion with an interval in the longitudinal direction;
A method comprising the steps of: In the folding step, both sides of the tubular synthetic resin film are forced inward in the width direction to form bellows-like folded portions on both sides of the tubular synthetic resin film,
In the cutting step, the inner end in the radial direction of only the folded portion present on one side of the tubular synthetic resin film is cut,
In the welding step, the folds are welded at intervals in the longitudinal direction only in the folds present on the one side of the tubular synthetic resin film.
The method of claim 1. In the welding step, an upstream welding line in the cover synthetic resin film located on the downstream side and a downstream welding line in the cover synthetic resin film located on the upstream side are simultaneously formed,
A separation step of cutting the elongated tubular synthetic resin film across the entire width direction between the upstream welding line and the downstream welding line after the welding step;
The method according to claim 1 or 2.