PUNCHING METHOD FOR LAMINATED CONTAINER

Abstract: A laminated peel container (A) of this invention includes an outside synthetic resin layer (1) having an air inlet (10) and an inside synthetic resin layer (2) so laminated inside the outside layer as to be capable of peeling, and only the portion of the inside layer in the proximity of the air inlet is in advance peeled from the outside layer. The air inlet can be formed by punching a punch from outside the outside layer at a mouth portion (4) of the laminated peel container (A) and cutting only the outside layer in such a manner as to leave the inside layer. The inside layer peeled partially in advance from the outside layer may be left swelling inward. The inside layer is preferably shaped from a synthetic resin having a bending modulus of not greater than 10,000 kg/cm 2 .

Description: The present invention relates to a punching method of an air suction hole in a separable laminated container A separable laminated container is made up of an outer layer and an inner layer which are made of synthetic resin. The inner layer is separably laminated to the outer layer. The separable laminated container is normally used in the sealed state with a pump installed to a neck portion thereof. As the liquid content is poured out by the pump, the inner layer is separated from the outer layer and shrinks according to the decrease of the liquid content. In order to smoothly conduct the shrinkage of the inner layer, the outer layer is provided with an air suction hole. As one of methods of forming such an air suction hole, a method in which the air suction hole is formed by partially fusing the outer layer of the separable laminated container has been proposed (for example, Japanese Published Unexamined Patent Application NO. H06-345069). In this method, the inner layer of the laminated container is made of resin having melting point higher than that of the outer layer and the resin of the outer layer is only fused to form the air suction hole by fusion means which is set at a temperature higher than the melting point of the outer layer and lower than the melting point of the inner layer. However, the method of forming the air suction hole as mentioned above has following problems. In case of a little difference between the melting points of the inner layer and the outer layer, it is quite difficult to fuse the outer layer only. Therefore, a predetermined difference in temperature between the melting points of the inner layer and the outer layer is required, thereby restricting the selection of resins used for the inner layer and the outer layer. Since the air suction hole is formed by fusing the resin of the outer layer by the fusion means, it is difficult to sharply form the air suction hole into a predetermined configuration. Therefore, a finishing is necessary to make the hole neat. Temperature control is necessary to keep the fusion means in a constant temperature range, thereby complicating the device. One of the objects of the present invention is to provide a method of forming an air suction hole in an outer layer in a desired configuration and the device. WO 9212926 discloses a separable laminated container. Such a container comprises integral body with a closed end and an open end. It includes a continuous inner layer which is readily separable from an outer layer at the closed end of the body but is joined to it at least at the open end. There is a separable laminated container in which an outer layer and an inner layer are partially bonded as disclosed in Japanese Published Unexamined Patent Application No. HO4-339759, Japanese Published Unexamined Patent Application No. HO5-310265, or the like. The position where the outer layer and the inner layer are bonded has been considered variously. For example, the bonded portion is provided linearly along the longitudinal direction of the separable laminated container. By the way, the separable laminated container is normally made in a method as described below. First, a laminated parison or laminated preform (hereinafter, referred to as the laminated parison) having a laminated structure corresponding to the separable laminated container to be manufactured is molded by extrusion molding. During this molding, a bonded area extending the axial direction is provided in a predetermined position in such a manner as to allow the separation between the outer layer and the inner layer besides the bonded area. then, the laminated parison is set in the mold and molded in to a desired bottle-like configuration by blow molding in such a manner as to have an air suction hole in the outer layer. For making sure to introduce air through the air suction hole, the position of the air suction hole should be shifted from the bonded area. When the diameter of the air suction hole is equal to or smaller than the width of the bonded area, overlap between the air suction hole and the bonded area results the blockage of the air suction hole so that air can not be introduced into a space the outer layer and the inner layer and the inner layer can not shrink. The first feature of the present invention is included in a punching method of an air suction hole in a separable laminated container comprising steps of: driving a punch from the outside into a neck of a container body made up of an inner layer and an outer layer which are made of synthetic resin and separably laminated on each other; and punching out the outer layer by the blade of the punch, leaving the inner layer behind. In the punching method with the first feature, the outer layer is punched by the blade of the punch leaving the inner layer behind so that the air suction hole can be formed only in the outer layer whereby the air suction hole can be quite easily formed. The air suction hole can be formed in the same configuration as that of the blade and the hole is neatly made only by the punching so that no finishing after the punching is required. Particularly when this punching method is conducted during the molded container is in a predetermined range of temperature after blow molding, it further facilitates and secures the formation of the air suction hole. The second feature of the present invention is included in a punching device comprising: (a) a pedestal which is inserted into a neck of a container body made up of an inner layer and an outer layer, which are made of synthetic resin and separably laminated on each other, to come in contact with an inner surface of the neck; (b) a punch supported in such a manner as to come close to and move away from the pedestal, the punch having a tubulous blade; and (c) a space keeping mechanism for keeping a distance between the tubulous blade and the pedestal constant when the punch is at the nearest position to the pedestal. The punching device with the second feature is suitable for carrying out the invention of the punching method with the first feature. The punching device with the second feature of the present invention has a simple structure and facilitates the formation of the air suction hole. Since the punch pushes the inner layer at the same time of punching out the outer layer, the separation between the layers are made around the air suction hole during punching, thereby allowing the inner layer to be quite easily separated from the outer layer. The punching device with the second feature further comprises an adjusting mechanism for adjusting the distance between the tubulous blade and the pedestal at a point in time when the punch is at the nearest position to the pedestal. As structured above, the adjusting mechanism adjusts the distance between the tubulous blade and the pedestal so that the air suction hole can be formed only in the outer layer even with a spread in the thickness of the inner layer. Brief Description of Drawings Fig. 1 is a front view showing a separable laminated container as an example. Fig. 2 is a front view showing a punching device of the first embodiment of the present invention, parts being broken away; Best Mode for Carrying Out the Invention Hereinafter, embodiments of the present invention will be described with reference to attached drawings. Fig 1 is a front view of a separable laminated container A as an example. The separable laminated container A is made up of an outer layer 1 and an inner layer 2, is formed by blow molding, and comprises a drum portion 3, a neck 4, and a bottom 5. The outer layer 1 is made of high-density polyethylene to keep the profile of the container, and the inner layer 2 is an inner bag made of nylon which is separable from the outer layer and deformable. There is a separated area 8 formed between the outer layer 1 and the inner layer 2 and a bonded area 9 where the outer layer 1 and the inner layer 2 are partly bonded in the longitudinal direction. The bottom 5 of the container A is provided with a projection 6 which is formed by pinch-offs of a mold during the molding. The projection 6 is provided with a plurality of sunk portions 7 which are arranged zigzag and each sunk in the opposite bonded layer. The projection 6 allows the inner layer 2 strongly bonded to the outer layer 1 even when the inner layer 2 is made of resin such as nylon providing weak bond strength, thereby preventing the occurrence of slit due to the separation between the layers and thus preventing the entrapment of moisture. The neck 4 is provided with an engaging portion 10 formed at an upper end of inner layer 2 by an air blowing member during the blow molding. The neck 4 is also provided with an air suction hole 11 formed by a punching device in a punching method of the present invention. The air suction hole 11 is a hole for introducing air into a space between the inner layer 2 and the outer layer 1 in order to smoothly achieve the separation of the inner layer 2 with keeping the profile of the container A to completely pour out the content. Hereinafter, the description will be made as regard to a method of punching the air suction hole and the punching device of the present invention, with reference to Fig. 2. The punching device B is disposed during cooling stage of the blow-molded container A and mounted on a supporting bed (not shown) capable of moving vertically and laterally. The punching device B comprises a receiving member B 1 and a cutting member B 2 which are mounted on a supporting member 20. The supporting member 20 is mounted on the supporting bed (not shown) and comprises a supporting shaft 21 and a guiding pole 22, wherein the guiding pole 22 is arranged in parallel with the supporting shaft 21 and is provided with a stopper 23 at the end thereof. The receiving member B 1 comprises a supporting pole 24, which is fixed to the supporting shaft 21 and extends downward, and a pedestal 25 disposed at an end of the supporting pole 24. The cutting member B 2 comprises a sliding member 30, which is not allowed to rotate relative to the supporting shaft 21 and the guiding pole 22 and is allowed to slide laterally, a supporting pole 31 extending downward from the sliding member 30, and a punch 32 disposed at the end of the supporting pole 31 in such a manner as to face the pedestal 25. The punch 32 is provided with a tubulous blade 33 at the end thereof and a clearance hole 34 formed therein for discharging a chip. The supporting pole 31 is provided with an internal thread 35 formed at the proximal end side thereof, into which a bolt 36 as a stopper is screwed and fixed by a lock nut 37 not to shift from a fixed position. Where the distal end 38 of the bolt 36 comes into contact with the supporting pole 24 of the receiving member B 1 , there is a distance t between the tubulous blade 33 and the receiving face 26 of the pedestal 25. The size of the distance t is adjustable by adjusting the position of the bolt 36 relative to the internal thread 35. It should be noted that the bolt 36 and the supporting pole 24 constitute a space keeping mechanism and the internal thread 35, the bolt 36, and the lock nut 37 constitute an adjusting mechanism. The supporting bed is provided with driving means (not shown) for moving the sliding member 30 laterally in such a manner that the sliding member 30 reciprocates between a waiting position where the sliding member 30 comes into contact with the stopper 23 disposed at the end of the guiding pole 22 and a punching position where the distal end 38 of the bolt 36 comes into contact with the supporting pole 24 of the receiving member. A combination of an electric or mechanical driving source, which is controlled in connection with the stopping member, and suitable transmitting means can be selected as the driving means, or manual means may also be employed as the driving means. Though the waiting position and the punching position of the sliding member 30 are defined by the stopping member in this embodiment, these may be defined by controlling the operational range of the driving means instead of the stopping member. The description will now be made as regard to the operation of the punching device B and the punching method of the present invention. As mentioned above, the punching device B is disposed during the cooling stage and the punching is performed during the container A has a predetermined temperature before returning to the room temperature. During the punching device B is in non-operation, the supporting bed is positioned above the container A in such a manner as to move the container A. Therefore, the receiving member B 1 and the cutting member B 2 are also positioned above the container A as well as the supporting member 20. The sliding member 30 is positioned at the waiting position at a predetermined distance from the supporting member 20. As the container A prior to punching is moved to a predetermined position, the supporting bed relatively moves downward against the container A, the supporting pole 24 mounted on the supporting member 20 is inserted into the neck 4 of the container A, and the pedestal 25 is disposed at a position being in contact with the inner layer 2. At the same time, the cutting member B2 mounted on the sliding member 30 moves downward as well as the supporting member 20 in such a manner that the pedestal 25 and the tubulous blade 33 of the punch 32 face each other to put the inner layer 2 and the outer layer 1 of the neck 4 of the container A therebetween. Then, the sliding member 30 is moved in the direction of X by the driving means so that the punch 32 moves until the distal end 38 of the bolt 36 comes into contact with the supporting pole 24. At this point, the punch 32 presses the inner layer 2 of the neck 4 of the container A to the receiving face 26 of the pedestal 25 and then the tubulous blade 33 is pressed to enter into the outer layer 1 of the neck 4 of the container A so as to punch the outer layer 1, leaving the inner layer 2 behind, thereby punching the air suction hole 11 in the outer layer 1. Since the punching is performed during the container A has the predetermined temperature after the container A is formed by blow molding, the outer layer is easily punched by the punch 32. After the punching, the sliding member 30 moves in the direction of Y to return to the waiting position and the supporting member 20 moves upward for the next punching. As the distance t between the tubulous blade 33 at the end of the punch 32 and the receiving face 26 is adjusted to the thickness of the inner layer 2, the air suction hole can be formed only in the outer layer 1. Though there is a spread in the thickness of the inner layer 2 formed by blow molding, the distance t is set to the minimum thickness of the inner layer 2, thereby punching the air suction hole 11 only in the outer layer 1 even with the spread in the thickness. In the next stage after the punching, for a pre-separation between the outer layer 1 and the inner layer 2, air is blown through the air suction hole 11 thus punched to introduce the air into a space between the inner layer 2 and the outer layer 1. Since the layers have been separated at the periphery of the air suction hole 11 during the punching, the separation throughout the layers can be easily made only by introducing a small amount of air. According to the punching method and the punching device of the present invention, the air suction hole 11 can be quite easily formed in the outer layer 1 of the neck 4 of the container A. Further, the air suction hole can be formed in a predetermined configuration by the tubulous blade, that is, the hole is neatly made only by the punching so that no finishing after the punching is required. In addition, the punching device can be easily structured.

Claims: A punching method of an air suction hole (11) in a separable laminated container (A) steps of: driving a punch from the outside into a neck (4) of a container body made up of an inner layer (2) and an outer layer (1) which are made of synthetic resin and separable laminated on each other; and punching out the outer layer (10 by the blade (33) of said punch, leaving the inner layer (2) behind. A punching device (b) comprising: (a) a pedestal (25) which is inserted into a neck (4) of a container body (A) made up of an inner layer (2) and an outer layer (1), which are made of synthetic resin and separably laminated on each other, to come in contact with an inner surface of the neck; (b) a punch (32) supported in such a manner as to come close to and move away from said pedestal (25), the punch having a tubulous blade (33); and (c) a space keeping mechanism for keeping a distance between the tubulous blade (33) and the pedestal (25) constant when said punch is at the nearest position to the pedestal. A punching device as claimed in claim 2, further comprising an adjusting mechanism for adjusting the distance between the tubulous blade (33) and the pedestal (25) at a point in time when said punch is at the nearest position to the pedestal.

Inventors: AKIYAMA YOSHIO, GOTO TAKAYUKI, NOMOTO TSUGIO, SHIBANO YOSHIO, YONEYAMA MASASHI, AKIYAMA, YOSHIO, GOTO, TAKAYUKI, NOMOTO, TSUGIO, SHIBANO, YOSHIO, YONEYAMA, MASASHI, Akiyama, Yoshio, Tochigi Plant, Shibano, Yoshio, Tochigi Plant
Applicants: YOSHINO KOGYOSHO CO LTD, YOSHINO KOGYOSHO CO., LTD.
Application year: 1996
Main classification: B65D1
IPC codes: B65D1, B29C49, B65D83, B05B11