JP2003341639A - Blow molded container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase contact bonding strength of a bottom sealed part and to strongly prevent bottom breakage from being generated by making the whole region of a parison pinch-off range on the pinch-off molded bottom sealed part of the bottom part of a blow molded laminated releasable plastic container to be a biting part formable range for increasing the contact bonding strength of a biting part, and to increase production speed of the blow molded laminated releasable plastic container with a high bottom breaking strength without undue effort. <P>SOLUTION: The bottom sealed part 14 of the bottom part 7 of the blow molded laminated releasable plastic container 1 is composed of the bottom rib 16 prepared by laminating and press-bonding a pair of rib pieces 15, and a plurality of biting parts 17 biting the other part from one of the rib parts 15 are provided. The length of the bottom wall 11 of the bottom part 7 along a parting line is set to an approximately same length as that of the parison pinch-off range w to make the whole region of the parison pinch-off range w to be a pinch-off formable range v. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a bottom seal portion of a blow-molded laminated release plastic container.

[0002]

2. Description of the Related Art A blow-molded bottle body generally called a deramie bottle, which is formed by laminating a bag-like inner layer having high flexibility on an outer layer having a high self-shape retention ability so as to be easily peeled off. Laminated release plastic containers are known.

This blow-molded laminated release plastic container is obtained by extrusion-molding an outer layer parison and an inner layer parison, which have almost no compatibility, into a laminated parison, and blow-molding the laminated parison. Since the bottom seal portion crushed and crushed at the pinch-off portion of the mold is basically a laminated structure of an outer layer portion and an inner layer portion which are hardly compatible with each other, bottom cracking easily occurs in the outer layer portion, There was dissatisfaction.

As a conventional technique for eliminating this dissatisfaction, a bottom seal portion, which is flattened by a pinch-off portion of a blow mold and bite-molded, is projected along a parting line by polymerizing and pressure-bonding a pair of rib pieces. There is a technique (see Japanese Patent Laid-Open No. 8-216238) in which a bottom rib formed in a strip shape is provided, and a plurality of biting portions that bite from one of the pair of rib pieces to the other are provided on the bottom rib.

In this prior art, as shown in FIGS. 7 and 8, a blow-molded delaminated plastic container in which a bottom portion 7 is provided at the lower end of a body portion 4 having a mouth tube portion 5 having an intake hole 6 at the upper end is provided. In 1, the bottom seal portion 14 is mainly composed of the ridge-shaped bottom rib 16 having a height width, so that the crimping area between the outer layer and the inner layer in the bottom seal portion 14 is increased, and the plurality of bite portions are included. Providing 17 not only further increases the crimping area between the outer layer and the inner layer, but also dramatically increases the resistance to shearing force parallel to the crimping surface, which prevents bottom cracking and provides sufficient mechanical strength. It is possible to obtain a very high bottom seal portion 14.

[0006]

However, in the above-mentioned prior art, since the structure of the bottom portion 7 where the bottom seal portion 14 is located, that is, the inside portion of the leg wall 8 is the slope portion 9, Bottom seal portion 1 located on this slope portion 9
The height of the four portions is lowered, and it is impossible to form the biting portion 17 in terms of dimensions.

For this reason, in the bottom seal portion 14, the bite part formable range v in which the bite part 17 can be formed becomes smaller than the parison bite cutting range w, and the parison outside this bite part formable range v is reduced. There has been a complaint that the demand for increasing the pressure bonding strength of the cut-off range w portion, that is, both side end portions of the bottom seal portion 14 cannot be sufficiently satisfied.

That is, the parison cut-off range w has a width which is larger than the width dimension obtained by flatly crushing the parison having the standard diameter by the fluctuation displacement described above in consideration of the fluctuation displacement of the parison. However, if the parison molding speed is increased in order to increase productivity, even if the parison is extruded and molded using the same synthetic resin material, the resulting parison diameter changes due to the MFR of the material and the molecular weight distribution of the resin. The swell ratio of the bottom seal part 14 is larger than that of the bottom seal part 14 in the case of a parison having a large diameter. This is because it will be outside the formable range v.

Particularly, in the case where the content liquid is poured out by utilizing the squeeze deformation of the body portion 4 of the container 1 instead of pouring out the content liquid by the pump assembled in the container 1, Since a large bending force acts on the bottom portion 7 when the squeeze of the portion 4 is performed, it is necessary to set the pressure bonding strength of the bottom seal portion 14 to such an extent that the bottom sealing portion 14 can sufficiently withstand this bending force. Since the biting portions 17 cannot be formed on both side end portions of the seal portion 14, there is a problem that the pressure bonding strength of the both side end portions of the bottom seal portion 14 cannot be increased.

Incidentally, by increasing the inclination angle of the sloped portion 9 of the leg wall 8, the bottom rib 16 portion whose height width is reduced by the sloped portion 9 is reduced, and the cutout forming possible range v is expanded. However, if the inclination angle of the sloped portion 9 is increased, the bottom portion 7 of the blow-molded container 1 is forcibly removed from the blow mold, and the bottom seal portion 14 is cracked by the releasing operation. However, it will easily occur.

Therefore, the present invention was devised to solve the above-mentioned problems in the prior art. The parison cutting range of the bottom seal portion of the blow-molded laminated release plastic container is set in the bottom seal portion. The technical issue is to make the entire area into a range in which the bite part that enhances the crimping strength of the bottom seal part can be formed.Therefore, the crimping strength of the bottom seal part is enhanced, and the occurrence of bottom cracking is strongly prevented.
Another object of the present invention is to reasonably increase the production rate of the blow-molded delaminated plastic container having high resistance to bottom cracking.

[0012]

[Means for Solving the Problems] [Means for Solving the Problems] Among the present invention for solving the above technical problems, the means of the invention according to claim 1 is a blow-molded laminated release plastic container, and an air intake hole is provided in the outer layer. That, the bottom seal part of the bottom part that is flattened and flattened by the pinch-off part of the blow mold is composed of a bottom rib formed into a ridge shape by polymerizing and crimping a pair of rib pieces. In the bottom rib, a biting part that bites from one of the pair of polymerized rib pieces to the other is arranged in a row, and the width along the parting line of the bottom wall of the bottom is approximately the width of the parison bite cutting range in the bottom rib. I set them equally.

The bottom seal portion, which is composed of a pair of ribs formed by superposing and pressure-bonding a pair of rib pieces in a ridge shape, has a wall structure in which an outer layer, an inner layer, an inner layer, and an outer layer are laminated in this order along the crimping direction. And has a ridge structure with a height width,
Since it has a large pressure-bonding area, a large pressure-bonding strength is exhibited even between the outer layer and the inner layer having low compatibility.

Since the biting portion formed on the bottom rib has a structure that bites from one rib piece to the other rib piece, the overlapping surface of the outer layer and the inner layer of the bottom rib is uneven at this biting portion. As a result, the superposed area is increased and the pressure bonding strength is increased, and the resistance against the shearing force parallel to the main part of the pressure bonding surface is increased.

Further, since the biting portion is formed by locally pressing and deforming the bottom rib due to a strong pressing force, a strong pressing force acts on the bottom rib portion in the vicinity of the biting portion. It will be strongly crimped to the inner layer and will exert strong crimping strength.

Further, since the width of the bottom wall along the parting line is substantially equal to the width of the parison cutting area in the bottom rib, the bottom rib portion in the parison cutting area has a sufficient height width. By this, the biting portion can be formed without difficulty in the entire area.

According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the biting direction of the biting portion is alternately inverted.

According to the second aspect of the invention, since the biting directions of the adjacent biting parts are opposite to each other, the outer layer and the inner layer in the vicinity of the biting part are forcibly pulled and greatly deformed. Therefore, the crimping area between the outer layer and the inner layer is increased, and the outer layer and the inner layer are more strongly crimped, whereby the crimping strength of the entire bottom seal portion is increased.

Further, since the biting portions are alternately located on the opposite side with respect to the main portion of the crimping surface, the plurality of biting portions bring both rib pieces into mesh with each other on both sides of the main portion of the crimping surface. The connection between the two rib pieces is structurally enhanced.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the invention, the entire area of the bottom rib portion located in the parison bite-cutting range of the bottom seal portion is set as the bite-portion formable range. Is.

According to the third aspect of the present invention, the biting portion is freely formed in the entire area of the bottom rib portion located in the parison bite cutting range which requires reinforcement of the bonding strength of the pair of polymerized rib pieces. Therefore, the reinforcement of the bonding strength of the pair of rib pieces can be achieved in a desired form.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a container 1 according to the present invention, FIG. 2 is a side view, and FIG. 3 is a bottom view. The container 1 is a synthetic resin material such as polyethylene or polypropylene, and has a required self-shape retention ability. And an outer layer 2 formed by being provided with a synthetic resin material having low compatibility with the outer layer 2 such as nylon, ethylene vinyl alcohol copolymer, polyethylene terephthalate, etc. 3 is a blow molding container in which 3 and 3 are laminated (see FIG. 2).

The body 4 of the container 1 has a cylindrical shape. The body 4 is erected continuously on the upper end of the body 4, and the outer layer 2 is provided in front of and behind the mouth cylinder 5 having a threaded outer peripheral surface. An intake hole 6 for introducing outside air between the outer layer 2 and the inner layer 3 is opened, and a bottom portion 7 having a circular bottom wall 11 is continuously provided at the lower end of the body portion 4.

The bottom portion 7 (see FIGS. 3 and 4) includes a peripheral leg wall 8 which constitutes a leg portion of the container 1, and a bottom wall 11 which is surrounded by the leg wall 8 and is depressed in the container 1. , A bottom seal portion 14 that is integrally connected to the bottom wall 11 and that is located on the parting line and crosses the bottom wall 11.

Leg wall 8 (see FIGS. 2, 3, 4 and 5)
Has a wall structure in which a substantially upright cylindrical wall portion on the outer side and a lower end of a tapered cylindrical slanted surface portion 9 having a downward diameter on the inner side are connected in an arc shape, and a parting line is located. At the lower end portion, an escape recess 10 having a depth larger than the height of a burr having a low height, which is shaped along the parting line, is formed.

Bottom wall 11 (see FIGS. 2, 3, 4 and 5)
Is a flat plate-shaped flat portion 12 continuous with the inner peripheral edge of the leg wall 8 and a substantially elliptic spherical arc wall shape that traverses the central portion of the flat portion 12 along the parting line and has the major axis along the parting line. The bottom wall 11 has a dome structure and is composed of a thick ridge 13 which is curved and depressed inward of the container 1.
The length of the parison along the parting line is approximately equal to the range length of the parison bite-out range w in the bottom rib 16.

That is, the length of the bottom wall 11 along the parting line is larger than that of the conventional example, and the blow ratio of the bottom portion 7 is correspondingly increased, but FIG. A case where the blow ratio is made circular and the blow ratio is increased uniformly over the entire circumference of the bottom portion 7 is shown. FIG. 4 shows that the bottom wall 11 is made substantially elliptical to increase the blow ratio in the direction orthogonal to the parting line. I try not to.

Bottom seal portion 14 (FIGS. 3, 4, 5, and 6)
(See) is located across the center of the raised portion 13 of the bottom wall 11 with both ends positioned on the sloped portion 9 of the leg wall 8, and when the parison is blow molded into the container 1, A pair of rib pieces 15 obtained by crushing and flattening the parison from the front and back is mainly composed of a bottom rib 16 which is formed by ridge-shaped molding by directly polymerizing and pressing the parison. On the end face, a cutting piece 19 which is a cutting mark of the parison remains and is formed over substantially the entire length of the bottom rib 16, and the range where the cutting piece 19 is located is a substantially parison cutting range w.

The bottom rib 16 has a recessed hole 18 that forms a biting portion 17 that bites from one rib piece 15 to the other rib piece 15 with a depth larger than the wall thickness of the rib piece 15 in the direction of depression. The rows are formed by alternately inverting them.

Further, the bottom seal portion 14 has an arch shape in which the whole is curved along the elliptic spherical arc surface of the raised portion 13, and due to the time-dependent shrinkage deformation after the completion of blow molding,
The center portion of the bottom wall 11 is reliably prevented from sagging and deforming.

As is apparent from FIG. 5, since both side ends of the cut-out piece 19 of the bottom rib 16 slightly enter the side of the sloped portion 9 of the leg wall 8, a pair of rib pieces 15 are formed. The portion of the bottom rib 16 located in the substantial parison cutting area w to be overlapped has its entire area located on the bottom wall 11, and thus has a sufficiently large height width.
Therefore, the entire area of the parison bite cutting w can be set to the bite formation possible range v without difficulty.

Therefore, the biting portions 17 can be easily formed at both end portions of the parison bite cutting range w without being disturbed by the sloped portion 9 of the leg wall 8, whereby the biting of the parison bite cutting range w is performed. Reinforcement by the portion 17 becomes reliable.

[0034]

Since the present invention has the above-mentioned structure, it has the following effects.

According to the first aspect of the present invention, the length of the bottom wall along the parting line is set to be substantially equal to the parison cutout range of the bottom rib, so that the height of the bottom rib portion in the parison cutout range is set. The width can be increased, which allows the entire area of the parison cutting edge to be the range where the bite part can be formed. Therefore, the pressure bonding strength of the entire bottom seal part is increased, and blow molding laminated peeling plastic with high resistance to bottom cracking. A container can be provided.

Further, since the entire area of the parison bite-cutting range of the bottom rib can be set as the bite-portion formable range,
Even if the parison molding speed is increased to increase the swell ratio, the range where the bite can be formed can be surely set within the parison bite range regardless of the size of the parison diameter. The blow molding production rate can be reasonably increased.

According to the second aspect of the invention, since the biting directions of the adjacent biting portions are opposite, both rib pieces bite into each other to be engaged with each other, and
The crimping force between the outer layer and the inner layer at the biting part is strengthened,
Further, the pressure-bonding area between the outer layer and the inner layer in the bottom seal portion is increased, so that the pressure-bonding strength between the outer layer and the inner layer in the bottom seal portion is further enhanced.

According to the third aspect of the present invention, the entire area of the bottom rib portion located in the parison cut-out range can be reliably reinforced by the cut-in portion, so that the occurrence of bottom cracking of the container is surely prevented.

[Brief description of drawings]

FIG. 1 is an overall front view showing a first embodiment of the present invention.

FIG. 2 is a side view, partly broken, of the embodiment shown in FIG.

3 is an overall bottom view of the embodiment shown in FIG.

FIG. 4 is an overall bottom view of another embodiment of the present invention.

FIG. 5 is an enlarged bottom vertical sectional front view of the embodiment shown in FIG. 1, taken longitudinally at a position slightly off the parting line.

FIG. 6 is an enlarged vertical cross-sectional side view of essential parts showing the details of the structure of the bottom seal portion of the embodiment shown in FIG.

FIG. 7 is an overall front view of a container showing a conventional technique.

8 is an overall bottom view of the container shown in FIG.

[Explanation of symbols]

1; Container 2; outer layer 3; Inner layer 4; torso 5; Mouth tube 6; Intake hole 7; bottom 8; Leg wall 9; Slope 10; escape recess 11; Bottom wall 12; Flat part 13; Raised part 14; Bottom seal part 15; Rib piece 16; Bottom rib 17; biting part 18; Recessed hole 19; Pieces w; parison cutting range v; Range where bite part can be formed

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 22:00 B65D 1/00 BF term (reference) 3E033 AA02 BA15 BA16 BA18 BA21 BA30 BB08 CA05 DA03 DB01 DD20 FA03 4F208 AG03 AG07 AG23 AH55 LB01 LB22 LW02 LW23 LW26

Claims (3)

[Claims] 1. A blow-molded laminated release plastic container having an outer layer (2) provided with an air intake hole (6), and a bottom portion which is flatly crushed by a pinch-off portion of a blow mold to be cut and formed ( Replace the bottom seal part (14) of (7) with a pair of rib pieces (1
(5) is composed of a bottom rib (16) formed by polymerizing and pressure-bonding to form a ridge, and the bottom rib (16) bites into one of the pair of polymerized rib pieces (15) into the other. 17) are arranged in rows,
The width along the parting line of the bottom wall (11) of the bottom part (7) is defined as the parison cutting range (w) in the bottom rib (16).
Blow-molded container set to approximately the same width. 2. The blow-molded container according to claim 1, wherein the biting direction of the biting part (17) is alternately inverted. 3. The blow-molded container according to claim 1 or 2, wherein the entire area of the bottom rib (16) located in the parison bite cutting range (w) of the bottom seal part (14) is the bite part formable range (v). .