JP7197117B2 - Delaminated bottle and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a delaminated bottle in which an inner layer bag is detachably laminated on the inner surface of an outer layer bottle, and a method for manufacturing the same.

Patent Literature 1 below discloses a bottomed tubular laminated bottle in which an inner layer bag that accommodates contents and that is deformed to reduce the volume as the contents are reduced is detachably laminated on the inner surface of the outer layer bottle. It is

In this conventional laminated bottle, a retaining rib is formed on the bottom surface (bottle bottom) of the outer layer bottle. The holding rib is a portion that sandwiches and integrally holds a part of the inner layer bag. The holding rib is formed to extend along the bottle bottom and in the bottle radial direction, and the length of the rib is at least half the diameter of the bottle bottom.

Further, an outside air introduction hole (intake groove) for sucking outside air into the space between the outer layer bottle and the inner layer bag is formed on the bottom surface of the outer layer bottle so as to be positioned on an extension line of the holding rib.

Japanese Patent No. 5961449 Japanese Patent No. 3817600

However, Patent Document 1 does not specifically disclose how the outside air introduction hole is formed by blow molding.

Normally, when the split mold for blow molding is clamped, the lower part of the tubular parison is pinched off, and the tubular parison is crushed in the radial direction at the cut part so that the opposing semi-peripheral wall parts become flat in cross section. forming a closed bottom of the parison in the blow mold. Thereafter, compressed air is blown into the parison whose bottom is closed to inflate the parison, and the parison is pressed against the inner surface of the mold to form a bottle shape.

In the case of blow molding of a laminated bottle as disclosed in Patent Document 1, a tubular laminated parison in which an inner layer is laminated on the inner surface of an outer layer is molded by a multilayer extrusion method or the like, and compressed air is injected into the laminated parison. A laminated bottle is formed by blowing in. When a laminated bottle is molded by such a multilayer blow molding method, there is no particular problem if the adhesion between the outer layer and the inner layer is high. If it is small and easily peelable, there is a problem that the bottom of the blow molded bottle is prone to cracking. That is, when the laminated parison is pinched off, as shown in FIG. Because of the presence of the outer layer half-peripheral walls 22, 22 facing each other, they are cut by the pinch-off blades 23, 23 in a state in which they are not tightly integrated. When blow molding is performed in this state, a slit 25 is formed in the bottom wall 24a of the outer layer bottle 24 as shown in FIG. A structure in which is sandwiched is obtained. However, when the outer layer and the inner layer are easily peeled off, as shown in FIG. 13, the bottom wall 24a of the outer layer bottle 24 is curled up to widen the width of the slit 25, causing a "cracking phenomenon". Sometimes it looks like it's cracked.

Patent Document 2 proposes a technique that reversely utilizes the above-mentioned "cracking phenomenon" in a delaminated bottle molded by a multilayer blow molding method. That is, by applying a pressing force along the parting line to the bottom wall of the bottle after blow molding, the bottom wall of the outer layer bottle is actively rolled up. Thereby, the slit functions as an outside air introduction hole for sucking outside air between the outer layer and the inner layer.

On the other hand, in the configuration disclosed in Patent Document 1, holding ribs provided on the bottom surface of the outer layer sandwich a part of the inner layer, thereby imparting rigidity to the outer layer by the holding ribs and preventing the outer layer from curling up. Furthermore, by making the inner layer bite into the outer layer within the holding ribs, the inner layer and the outer layer are firmly fixed, and this structure also helps prevent the "crack phenomenon".

As described above, when the laminated parison is pinched off, part of the inner layer should be sandwiched in the outside air introduction hole formed in the bottom wall along the extension of the holding rib, as shown in FIG. 12 of the present application. However, in FIG. 5 of Patent Document 1, the outside air introduction hole is formed in an open state, and a part of the inner layer is not sandwiched in the outside air introduction hole. In order to form the outside air introduction holes in an open state in this way, it is necessary to provide a separate mold member for forming the outside air introduction holes in the outer layer. No specific molding method is disclosed.

Further, in the case of a structure in which a part of the inner layer is sandwiched between the outside air introduction holes as shown in FIG. The first rib-shaped portion of the inner layer sandwiched between the holding ribs and the second rib-shaped portion of the inner layer sandwiched between the outside air introduction holes are structurally integrated, and the rigidity of the second rib-shaped portion of the inner layer is increased. As a result, the second rib-like portion becomes difficult to get out of the outside air introduction hole, and it may be difficult to open the outside air introduction hole.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a delaminated bottle capable of being easily molded and having an outside air introduction hole easily opened, and a method for manufacturing the same.

In order to achieve the above object, the present invention has taken the following technical measures.

That is, the present invention comprises an outer layer bottle having a cylindrical body with a bottom, and an inner layer bag detachably laminated on the inner surface of the outer layer bottle, and the inner layer bag accommodates the content liquid. The ribs to be held are formed on the bottom surface of the inner layer bag and extend along the radial direction. In the delaminated bottle, a pair of holding ribs are formed to hold, and an outside air introduction hole for introducing outside air into a space between the outer layer bottle and the inner layer bag is provided in the outer layer bottle, wherein the outside air introduction hole is , an opening is formed in the outer peripheral surface of the outer layer bottle in the vicinity of the lower end of the body portion, and is formed at a position where a plane including a straight line along the direction in which the held rib extends and the outer peripheral surface of the body portion of the outer layer bottle intersect. It is characterized by

According to such a laminated bottle of the present invention, it is not on the extension line of the holding rib in the portion located at the bottom of the outer layer bottle, that is, not on the extension line of the holding rib on the bottom surface of the outer layer bottle, but on the outer peripheral surface near the lower end of the barrel of the outer layer bottle. Since the outside air introduction hole is formed, the inner layer bag is laminated on the inner surface of the outer layer bottle and is not separated from the inner layer bag. Even so, the structural integrity between the side ribs and the ribs to be held can be relaxed, and the rigidity of the side ribs can be reduced. An introduction hole can be opened. In addition, an outside air introduction hole is opened at a position where a plane including a straight line along the extending direction of the held rib intersects with the outer peripheral surface of the barrel of the outer layer bottle, although it is not on the held rib or the extension of the holding rib. By forming them, both the rib to be held and the air introduction hole can be positioned on the parting line of the split mold for blow molding. With such a configuration, when the split mold for blow molding is clamped, the pinch-off blade crushes the laminated parison in the mold clamping direction to widen the width of the laminated parison in the direction along the pinch-off blade, so that the holding rib and the held rib are formed. By cutting the lower end and the outer peripheral surface near the lower end of the body with a pinch-off blade, the outside air introduction hole can be easily formed in the outer peripheral surface near the lower end of the body of the outer layer bottle.

In the delaminated bottle of the present invention, the plane including the straight line along the direction in which the ribs to be held extend may be a plane including the axial center of the outer layer bottle. According to this, the simplification of the split mold of blow molding is achieved.

At least one end of the rib to be held extends to the outer peripheral edge of the bottom wall of the outer layer bottle, and the side rib is in a state in which the inner layer bag is laminated on the inner surface of the outer layer bottle and is not peeled off therefrom. and may extend upward from the one end of the held rib. According to this, the side ribs are substantially orthogonal to the ribs to be held, and the presence of the bent portion can ensure the deformability of the side ribs. Both ends of the rib to be held in the longitudinal direction may extend to the outer peripheral edge of the bottom wall of the outer layer bottle, and the outside air introduction holes may be provided at two diametrically opposed locations on the body of the outer layer bottle, The inner layer bag may be provided with two side ribs that fit into their respective outside air introduction holes.

The barrel of the outer layer bottle has a relatively large diameter barrel body and a relatively small diameter barrel lower end connected to the lower part of the barrel body. It may be provided at the lower end of the body portion. According to this, since the outer air introduction hole is formed in the lower end of the body portion having a relatively small diameter, the laminated parison is pressed in the die clamping direction until it reaches the outer air introduction hole, and the laminated parison is pushed in the direction along the parting line. It becomes easier to widen the width of More preferably, the height of the lower end of the barrel is slightly larger than the outside air introduction hole, for example less than 150%, more preferably less than 120%, of the height of the upper end position of the outside air introduction hole from the bottom end of the bottle. can be Also, the vertical dimension of the lower end of the trunk is preferably less than 1/8 of the vertical dimension of the trunk main body. Further, the dimension of the step between the outer peripheral surface of the lower end of the barrel and the outer peripheral surface of the main body of the barrel is preferably 0.6 to 1.4 times the wall thickness of the outer peripheral wall of the outer layer bottle. According to this, when the outer layer bottle is viewed obliquely from above, the external air introduction hole is hidden by the main body portion of the body portion, thereby improving the appearance and merchantability of the product.

Further, the body of the outer layer bottle has a circular or elliptical cross section, and at least one flat cutout portion is provided in the vicinity of the lower end of the outer peripheral surface of the body of the outer layer bottle in the circumferential direction. The outside air introduction hole may be formed in the notched portion.

The delaminated bottle of the present invention can be molded by an appropriate molding method, preferably by a direct blow molding method. Specifically, a step of extruding a tubular laminated parison in which an inner layer is laminated on the inner surface of an outer layer, and a pinch-off blade provided in a split mold when the lower part of the laminated parison is clamped in a split mold for blow molding. and a step of molding the delaminated bottle by blowing compressed air into the laminated parison after clamping the split mold for the blow molding. The pinch-off blade preferably has a first portion along the lower end surface of the holding rib of the outer layer bottle to be molded and a second portion along the outer peripheral surface of the body portion of the outer layer bottle to be molded. When the mold is clamped, the pinch-off blade crushes the laminated parison in the mold-clamping direction to widen the width of the laminated parison in the direction along the pinch-off blade. part can be cut. As a result, by cutting the laminated parison with the second part, a slit-shaped outside air introduction hole is formed in the portion corresponding to the outer peripheral surface near the lower end of the body of the outer layer bottle, and the side ribs of the inner layer bag are sandwiched inside. After blow molding, the outside air introduction hole formed in the side surface of the body can be opened by detaching the side rib from the outside air introduction hole by pressing deformation of the body of the outer layer bottle.

1 is a perspective view of a delaminated bottle according to a first embodiment of the present invention; FIG. It is a reference exploded view of the delaminated bottle. It is a vertical cross-sectional view showing a vertical cross-section along the X-axis direction (direction along the parting line) of the delaminated bottle. Fig. 2 is an enlarged perspective cross-sectional view showing a longitudinal section along the Y-axis direction (clamping direction of a split mold for blow molding) in the vicinity of the bottom of the delaminated bottle. It is a longitudinal cross-sectional view along the X-axis direction for explaining the action of the delaminated bottle. It is a vertical cross-sectional view along the clamping direction of a blow molding die for molding the same delaminated bottle. It is a longitudinal cross-sectional view along the parting line of the same blow molding die. FIG. 4 is a front view of a delaminated bottle according to a second embodiment of the present invention; It is a side view of the same lamination peeling bottle. It is a perspective view of the same delamination bottle. FIG. 4 is a vertical cross-sectional view of a blow molding die and a laminated parison for explaining a state in which the lower portion of the laminated parison is pinched off; FIG. 2 is a longitudinal cross-sectional view of the bottom of a laminated bottle blow molded from a laminated parison; FIG. 4 is a vertical cross-sectional view showing a state in which the bottom surface of the outer layer of the laminated bottle is cracked.

Preferred embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a delaminated bottle 1 according to a first embodiment of the present invention, and the delaminated bottle 1 is detachably laminated on the outer layer bottle 2 and the inner surface of the outer layer bottle 2. It is mainly composed of an inner layer bag 3. The outer layer bottle 2 can be molded from a synthetic resin material such as PET or EVOH in order to provide strength and squeezability as a discharge container. It can be molded from a synthetic resin material, for example, a polyolefin resin material such as polyethylene, which has the property of shrinking easily as the content liquid decreases.

The outer layer bottle 2 has a bottomed cylindrical body 5 whose lower end is closed by a bottom wall 4 and a mouth 7 integrally provided at the upper end of the body 5 with a shoulder 6 interposed therebetween. have. The mouth portion 7 is cylindrical and has a male thread formed on its outer periphery for screwing a cap or the like. Since the inner layer bag 3 is laminated on the inner surface of the outer layer bottle 2 , it basically has the same structure and shape as the outer layer bottle 2 , but is thinner than the outer layer bottle 2 . there is The inside of the inner layer bag 3 is filled with the content liquid through its mouth. Further, the mouth portion 7 of the outer layer bottle 2 is preferably equipped with a discharge device having a pump mechanism for sucking up the content liquid.

The inner layer bag 3 has a shape following the shape of the inner surface of the outer layer bottle 2 as shown in FIG. It shrinks to a free shape as it decreases. Although FIG. 2 is an exploded view, it is impossible to actually disassemble the inner layer bag 3 while maintaining the shape of the inner layer bag 3 as shown in FIG. Collapse. Further, the outer layer bottle 2 shown in FIG. 2 is illustrated as a cross-sectional perspective view in which half in the radial direction is cut.

In the illustrated embodiment, the body portion 5 of the outer layer bottle 2 has a cylindrical cross-section. and a trunk lower end portion 5b having a split vertical dimension. The trunk lower end portion 5b is formed integrally with the lower end of the trunk main body portion 5a via a cut portion. Both the trunk body portion 5a and the trunk lower end portion 5b are formed to have a cylindrical cross section. The trunk body portion 5a is formed with a relatively large diameter, and the trunk portion lower end portion 5b is formed with a relatively small diameter. The dimension of the step between the trunk main body portion 5a and the trunk lower end portion 5b, that is, the difference between the radius of the trunk main body portion 5a and the radius of the trunk lower end portion 5b in this embodiment is as shown in FIG. , and approximately the same thickness as the body portion 5 of the outer layer bottle 2 .

The bottom wall 4 of the outer layer bottle 2 is formed integrally with the lower edge of the body lower end portion 5b. The bottom wall 4 as a whole is formed in a spherical shape convex upward. The bottom surface of the bottom wall 4 constitutes the bottom surface of the outer layer bottle 2 . Further, the bottom surface of the inner layer bag 3 is in contact with the inner surface (that is, the upper surface) of the bottom wall 4 in the laminated state.

The bottom surface of the inner layer bag 3 is integrally formed with a held rib 8 extending linearly over the entire length in the diametrical direction. On the other hand, on the bottom surface of the outer layer bottle 2, as shown in FIG. 4, a pair of holding ribs 9, 9 holding the held rib 8 therebetween are integrally formed. The thickness of each retaining rib 9 is greater than the thickness of the retained rib 8 in order to provide rigidity necessary for retention. In addition, in order to hold the inner layer bag 3 more securely, the ribs to be held 8 and the holding ribs 9, 9 are fitted to each other in an appropriate position by inserting a pin into these ribs when the split mold for blow molding is clamped. A concave-convex fitting structure is formed by abutting against 8 and 9 from the side.

The outer layer bottle 2 is provided with an outside air introduction hole 10 for introducing outside air into the space between the outer layer bottle 2 and the inner layer bag 3 . The outside air introduction holes 10 are formed on the outer peripheral surface of the body lower end portion 5b at two diametrically opposed locations. In particular, in this embodiment, the outside air introduction hole 10 is formed in a vertically extending slit shape at a position where the bottle vertical section including a straight line along the direction in which the held rib 8 extends and the outer peripheral surface of the body lower end portion 5b intersect. formed.

On the other hand, the inner layer bag 3 is laminated on the inner surface of the outer layer bottle 2 and integrally has a side rib 11 which is fitted into the outside air introduction hole 10 from the inner surface side in a state where it is not separated therefrom. This side rib 11 is formed so as to continue to the held rib 8 . That is, both ends of the rib 8 to be held extend to the outer peripheral edge of the bottom wall 4 of the outer layer bottle 2, and each side rib 11 is formed so that the inner layer bag 3 is laminated on the inner surface of the outer layer bottle 2 and is not peeled off therefrom. In this state, they extend upward from both ends of the rib 8 to be held.

6 and 7 show a blow molding die 12 for molding the delaminated bottle 1 by direct blow molding. The blow molding die 12 is mainly composed of a pair of left and right split dies 12L and 12R, and a core pin 13 for molding the inner surface shape of the mouth of the bottle and for blowing compressed air.

Each split mold 12L, 12R has a cavity that forms the outer surface shape of each part of the outer layer bottle. Each of the split dies 12L, 12R has a pinch-off blade for cutting the lower part of the laminated parison when the dies are clamped. In particular, in this embodiment, the pinch-off blade has a first portion 14A along the lower end surface of the holding rib of the outer layer bottle to be formed and a second portion 14B along the outer peripheral surface of the lower end portion of the body portion of the outer layer bottle to be formed. have.

Next, a method of blow-molding the delaminated bottle 1 using the blow-molding mold 12 will be described. First, a tubular laminated parison in which an inner layer is laminated on the inner surface of an outer layer is extruded from a die of a multilayer extruder (not shown) into a blow molding die 12 that opens to one side. The laminated parison in its extruded state is designated A in FIGS.

Next, as shown in FIG. 6, the blow molding die 12 is clamped. At this time, the cylindrical laminated parison is pushed from both sides in the diameter direction by the first portions 14A of the pinch-off blades and crushed in the mold clamping direction. spreads out as shown in FIG. The laminated parison in its crushed condition by the pinch-off blade first portion 14A is shown at B in FIGS. As shown in the figure, when the laminated parison is crushed and widened in the direction along the pinch-off blades 14A, the side portions of the laminated parison are cut by the second portions 14B of the pinch-off blades during mold clamping. Thus, the diameter of the laminated parison to be extruded and the diameter near the lower end of the outer layer bottle body to be molded are designed.

Then, when the clamping is completed, the lower part of the laminated parison is cut by pinch-off blades 14A, 14B provided on split dies 12L, 12R for blow molding. Thereafter, the delaminated bottle 1 is blow-molded by driving the core pin 13 into the laminated parison from above and blowing compressed air into the laminated parison.

The present invention is not limited to the above embodiments, and can be modified in design as appropriate. For example, unlike the second embodiment shown in FIGS. 8 to 10, the lower end of the body portion of the outer layer bottle 2 is configured in a cylindrical shape with a small diameter. It is also possible to provide flat notch-like portions 15 at two diametrically opposed locations in the vicinity of the lower end portion of the surface, and to form the outside air introduction holes 10 in these notch-like portions 15 . In addition, although the body of the outer layer bottle has been described as having a circular cross section in the above embodiment, it may have an elliptical cross section or any other suitable flat bottle shape.

1 delaminated bottle 2 outer layer bottle 3 inner layer bag 4 bottom wall 5 trunk 5a main body 5b lower end 8 held rib 9 holding rib 10 outside air introduction hole 14A first portion of pinch-off blade 14B second portion of pinch-off blade

Claims (6)

It comprises an outer layer bottle having a cylindrical body with a bottom and an inner layer bag detachably laminated on the inner surface of the outer layer bottle, and the inner layer bag accommodates a liquid content therein so that the content liquid is reduced. The bottom surface of the inner layer bag is formed with ribs to be held extending along the radial direction, and the bottom surface of the outer layer bottle is formed with a pair of holding ribs that sandwich and hold the ribs to be held of the inner layer bag. is formed, and the outer layer bottle is provided with an outside air introduction hole for introducing outside air into the space between the inner layer bag,
The outside air introduction hole is formed in the outer peripheral surface of the outer layer bottle in the vicinity of the lower end of the body portion, and the outer peripheral surface of the body portion of the outer layer bottle intersects with a plane including a straight line along the direction in which the held rib extends. A delaminated bottle that is formed in a position to 2. The delamination bottle according to claim 1, wherein the inner layer bag is laminated on the inner surface of the outer layer bottle and is not separated from the inner layer bag, and integrally has side ribs that fit into the outside air introduction hole from the inner surface side. A delaminated bottle. 3. The delaminated bottle according to claim 2, wherein at least one end of said rib to be held extends to the outer peripheral edge of the bottom wall of said outer layer bottle, and said side rib is formed so that said inner layer bag is laminated on the inner surface of said outer layer bottle. a delaminated bottle extending upwardly from said one end of said retained rib in a delaminated state and not delaminated therefrom. 4. The delaminated bottle according to claim 1, 2 or 3, wherein the body of the outer layer bottle comprises a relatively large-diameter body and a relatively small-diameter body connected to the bottom of the body. and a lower end portion, wherein the outside air introduction hole is provided in the lower end portion of the body portion. 4. The delaminated bottle according to claim 1, 2 or 3, wherein the body of the outer layer bottle has a circular or elliptical cross-section, and at least one point in the circumferential direction near the lower end of the outer peripheral surface of the body of the outer layer bottle. A delaminating bottle, wherein a flat notch-shaped portion is provided on the bottom of the bottle, and the outside air introduction hole is formed in the notch-shaped portion. A method for producing a delaminated bottle according to any one of claims 1 to 5,
a step of extruding a tubular laminated parison in which an inner layer is laminated on the inner surface of an outer layer;
a step of cutting the lower part of the laminated parison with a pinch-off blade provided in the split mold when the split mold for blow molding is clamped;
forming the delaminated bottle by blowing compressed air into the laminated parison after clamping the split mold for the blow molding;
The pinch-off blade has a first portion along the lower end surface of the holding rib of the outer layer bottle to be molded and a second portion along the outer peripheral surface of the body portion of the outer layer bottle to be molded,
When the mold is clamped, the pinch-off blade crushes the laminated parison in the mold-clamping direction to widen the width of the laminated parison in the direction along the pinch-off blade, so that the second portion of the pinch-off blade partially clamps the laminated parison. A method of manufacturing a delaminated bottle that is cut.

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