JP2010012605A - Synthetic-resin laminated bottle body, injection molding machine, and method for forming laminated preform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the problem of delamination in a synthetic-resin laminated bottle body by biaxially stretching blow molding, and to provide the laminated bottle body with delamination suppressed effectively and a method for molding such a laminated bottle body. <P>SOLUTION: An injection molding machine has a plurality of blockade vertical rib pieces, which partition a middle channel in the peripheral direction into a plurality of channels, parallelly arranged in a range from a prescribed position of the annular middle channel forming an intermediate layer to a junction, in a multiple nozzle part in which a plurality of molten resins are piled up. Using the injection molding machine, over a prescribed height region, the intermediate layer is piled up between substrate layers, a longitudinal connection strip part with the substrate layers connected without the intermediate layer is parallelly extended/formed along the central axis direction, in the peripheral direction, and a preform is molded with the intermediate layer partitioned in the peripheral direction by the longitudinal connection strip part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a synthetic resin laminated casing by biaxial stretch blow molding in which an intermediate layer is laminated, a method for molding a laminated preform which is a primary molded product thereof, and an injection molding apparatus used for molding the preform.

  2. Description of the Related Art Biaxially stretched blow molded bodies made of polyethylene terephthalate (hereinafter abbreviated as PET) resin are used in various fields such as beverages, foods, and cosmetics. Particularly in applications that require gas barrier properties, a casing is used in which a gas barrier resin such as a nylon resin or an ethylene vinyl alcohol copolymer resin is laminated as an intermediate layer on a PET resin, which is a main material resin.

Patent Document 1 describes a method for forming a laminated casing obtained by biaxial stretch blow molding in which such a gas barrier resin is laminated, and a test tubular laminated preform which is a primary molded product thereof. 11 and 12 show typical examples of such a case and preform.
A housing 601 shown in FIG. 11 has a mouth tube portion 602, a neck ring 603, a cylindrical body portion 605, and a bottom portion 606, and is made of PET resin in a height region excluding the upper end portion and the bottom portion 606 of the mouth tube portion 602. An intermediate layer 613 made of nylon resin, which is a gas barrier resin, is laminated between the outer layer 611 and the inner layer 612.

The housing 601 can be formed by biaxially stretch-blow-molding the preform 501 shown in FIG. 12. The preform 501 includes a mouth tube portion 502, a neck ring 503, a cylindrical body portion 505, and a bottom portion. In the height region excluding the mouth tube portion 502 and the bottom portion 506, an intermediate layer 513 made of nylon resin, which is a gas barrier resin, is laminated between an outer layer 511 made of PET resin and an inner layer 512.
JP-A-1-254539

Here, in the biaxially stretched blow housing in which a gas barrier resin such as nylon resin is laminated as an intermediate layer on the PET resin layer as the main material resin as described above, the PET resin layer and the gas barrier resin layer are in close contact with each other. In many cases, it is not glued. For this reason, for example, in applications where the inside of a carbonated beverage or the like is in a pressurized state, there is no problem when the inside before use is in a pressurized state, but when the cap is removed, a large shear is caused by a sudden change in pressure. Both layers may peel due to the action of force.
In this way, once both layers are peeled off, they do not come into close contact with each other, but light is scattered or reflected at the peeling interface, which is recognized from the outside, and the appearance is impaired. Occurs.
In the shrinking process after biaxial stretch blow molding, there is also a problem that delamination occurs due to the difference in shrinkage between the intermediate layer and the outer layer or the inner layer.

An object of the present invention is to suppress the problem of delamination as described above in a laminated case by biaxial stretching blow, and a synthetic resin-made laminated case in which delamination is effectively suppressed, An object of the present invention is to provide a method for forming such a laminated casing.

The present invention relates to a synthetic resin-made laminated casing by biaxial stretch blow molding, a method for molding a laminated preform used for molding the casing, and an injection molding apparatus used for molding the preform. The laminated housing, the injection molding apparatus, and the molding method of the laminated preform using this injection molding apparatus will be described in this order.
First, the main structure related to the synthetic resin laminated casing in the present invention that solves the above technical problem is as follows.
A casing obtained by biaxially stretching blow molding a test tube synthetic resin laminated preform in which at least one intermediate layer is laminated on a base layer made of a main material resin,
The intermediate layer is laminated between the base layers over a predetermined height region,
In this predetermined height region, there are a plurality of longitudinal strip connecting portions in which a base layer laminated on both sides of the intermediate layer without any intermediate layer is directly welded. Extending along, and by dividing the intermediate layer in the circumferential direction by this vertical belt-like connecting portion,
It is said.

  With the above configuration, the intermediate layer is divided in the circumferential direction by the longitudinal belt-like connecting portion in which the base layer laminated on both sides of the intermediate layer is directly welded, so that the shear force acting between the intermediate layer and the base layer is exerted. Will act in a state where the left and right ends are constrained by the vertical belt-like connecting portion, and the occurrence of delamination can be effectively suppressed accordingly.

Here, the laminated structure composed of the base layer and the intermediate layer can take various forms. For example, two types and three layers (base layer / intermediate layer / base layer), two types and five layers (base layer / intermediate layer / Substrate layer R / intermediate layer / substrate layer), 3 types and 4 layers (substrate layer / intermediate layer A / intermediate layer B / substrate layer), 3 types and 4 layers (substrate layer / substrate layer R / intermediate layer / substrate layer), Layered structure of 3 types 5 layers (base layer / intermediate layer A / base layer / intermediate layer B / substrate layer), 3 types 5 layers (base layer / intermediate layer / substrate layer R / intermediate layer / substrate layer), etc. Even in the case where a plurality of intermediate layers are formed, the longitudinal strip connecting portions in which the base layers laminated on both sides of the intermediate layer are directly welded are arranged in the center in the circumferential direction. The intermediate layer can be divided in the circumferential direction by extending along the axial direction and by the longitudinal belt-like connecting portion.
In the above description, the intermediate layer A and the intermediate layer B indicate that these intermediate layers are made of different resins, and the base layer R indicates that the recycled material of the main material resin is used.

  According to another configuration of the synthetic resin-made laminated casing of the present invention, in addition to the main configuration described above, a portion excluding the mouth tube portion and the bottom portion is defined as a predetermined height region.

The height region where the intermediate layer is laminated, or the number or width of the vertical belt-like connecting portion, the form of use, the function based on the intermediate layer such as the gas barrier property, the preform, or this preform It can be determined appropriately in consideration of the moldability (productivity) of the casing as the primary molded product, and the height region where the intermediate layer is laminated can be set to the entire height range of the casing.
Here, the mouth tube portion is a portion that is not stretched by biaxial stretch blow molding, and the bottom portion is a portion that is not sufficiently stretched, and it is easy for deformation to occur by laminating the intermediate layer. By making the mouth tube part and the bottom part a region where the intermediate layer is not stacked as in the configuration, it is possible to effectively prevent the problem that the sealing performance by the cap in the mouth tube part or the standing property of the casing at the bottom part is impaired. Can do.

  Still another structure relating to the synthetic resin laminated casing of the present invention has a two-layer / three-layer structure composed of a main material resin and a gas barrier resin forming an intermediate layer in addition to the main structure described above. It is said.

The above configuration is a configuration for improving the gas barrier property of the housing by making the intermediate layer made of a gas barrier resin. Typically, for example, nylon resin / PET such as PET / MXD-6, PET / EVOH / PET , PP / EVOH / PP gas barrier resin, PLA / PGA / PLA and the like.
(In the description of the layer structure, EVOH represents an ethylene vinyl alcohol copolymer, PP represents a polypropylene resin, PLA represents polylactic acid, and PGA represents polyglycolic acid.)

In order to further improve the barrier property of the intermediate layer made of gas barrier resin, oxygen scavenger and oxygen absorbent are mixed and dispersed in the gas barrier resin, or layered silicate is dispersed in MXD-6 nylon resin. It can also be a composite material.
An intermediate layer made of a cyclic polyolefin resin is effective as a barrier resin against moisture.

Next, the main structure which concerns on the injection molding apparatus among this invention is:
A test tube laminate preform for biaxial stretch blow molding having at least one intermediate layer on a base layer made of a main material resin is injection-molded.
At least two resin supply portions for supplying an intermediate layer resin that forms an intermediate layer with the main material resin, a multiple nozzle portion for laminating the main material resin and the intermediate layer resin, and a mold for forming a preform. An injection molding device,
Multiple nozzle part
At least three annular inner channels and outer channels that form a base layer made of a main material resin, and an annular middle channel that forms an intermediate layer made of an intermediate layer resin between the inner channel and the outer channel. Having a layer formation flow path,
On the downstream side of these at least three layer formation channels, a merge channel is disposed via a junction where the molten resin flowing in each layer formation channel merges,
In the range from the predetermined position of the middle flow path through which the intermediate layer resin flows to the confluence, a plurality of cut-off longitudinal rib pieces crossing the middle flow path are arranged in parallel in the circumferential direction. Dividing the road into a plurality of flow paths in the circumferential direction,
It is said.

  According to the injection molding apparatus having the above-described configuration, the middle flow path is flowed by the plurality of blocking vertical rib pieces arranged in parallel in the circumferential direction in a range from the predetermined position of the middle flow path through which the intermediate layer resin flows to the junction. The annular intermediate layer resin can be divided in the circumferential direction, and the intermediate layer can be laminated between the base layers with the intermediate layer divided in the circumferential direction. The base layers are connected.

  In addition, according to the structure of the said injection molding apparatus, by adding a supply part suitably or adding an annular | circular shaped flow path with a multiple nozzle in the structure range of laminating | stacking with a base layer on both sides of an intermediate | middle layer. The laminated structure of the laminated preform can be a laminated structure of 2 types, 3 layers, 2 types, 5 layers, 3 types, 4 layers, 3 types, 5 layers, etc. as described above.

Next, the main molding method of the laminated preform of the present invention is the synthetic resin lamination by the biaxial stretch blow molding having the above-described vertical belt-like connecting portion of the present invention using the above-described injection molding apparatus of the present invention. It is a method for molding a test tubular laminated preform as a primary molded product of a casing,
The main material resin forming the base layer is supplied from one supply part to the inner flow path and the outer flow path, and the intermediate layer resin forming the intermediate layer is supplied from the other supply part to the intermediate flow path. The intermediate layer resin is divided in the circumferential direction by the blocking vertical rib pieces, and the intermediate layer resin is divided between the main flow resin from the inner flow path and the outer flow path in the state of being divided in the circumferential direction at the merge point, and merged. Forming a laminated molten resin fluid in the road,
Filling the mold cavity with this laminated molten resin fluid,
It is said.

  According to the above molding method, a laminated region in which an intermediate layer is laminated between base layers, and there is no intermediate layer in the laminated region, and a vertical belt-like connecting portion in which base layers laminated on both sides of the intermediate layer are connected, A plurality of in the circumferential direction, in parallel, formed along the central axis direction, by this longitudinal strip-shaped connecting portion, it is possible to mold a laminated preform for biaxial stretch blow molding in which the intermediate layer is divided in the circumferential direction, By carrying out biaxial stretch blow molding of this laminated preform, a synthetic resin laminated casing in which the intermediate layer is divided in the circumferential direction by the above-described longitudinal belt-like connecting portion of the present invention can be obtained.

In another molding method of the present invention, in the main molding method described above, a main material resin for forming a base layer at a predetermined pressure or speed is supplied from one supply unit to the inner channel and the outer channel, for a predetermined time.
In addition, the intermediate layer resin that forms the intermediate layer from another supply unit is supplied to the middle flow path at the same time within the predetermined time range,
It is said.

Here, it is said that the intermediate layer resin for forming the intermediate layer is supplied to the middle flow path from another supply section at the same time within a predetermined time range in which the main material resin forming the base layer is supplied to the inner flow path and the outer flow path. The method is a so-called simultaneous injection method, and the intermediate layer is formed in a predetermined height region of the preform by appropriately setting the supply start time and supply stop time of the intermediate layer resin to the middle flow path. Can be stacked.

The present invention is the above-described method and configuration, and has the following effects.
First, in the invention relating to the biaxially stretched blow laminated casing of the present invention,
By dividing the intermediate layer in the circumferential direction at the longitudinal strip connecting portion to which the base layer is connected, the action of the shearing force acting between the intermediate layer and the base layer is constrained by the longitudinal strip connecting portion. Accordingly, it is possible to effectively suppress the occurrence of delamination due to molding shrinkage and pressure fluctuation in the housing.

  In the invention relating to the injection molding apparatus of the present invention, a plurality of the longitudinal longitudinal rib pieces arranged in parallel in the circumferential direction flow in the middle flow path in a range from the predetermined position of the middle flow path to the junction. The annular intermediate layer resin is divided in the circumferential direction, and the intermediate layer can be laminated between the base layers at the junction in such a divided state, and the intermediate layer is laminated on both sides of the intermediate layer. The base layer to be connected is connected.

  In the method for molding a laminated preform of the present invention, the injection molding apparatus of the present invention is used, and an intermediate layer is laminated between the main layers, and in the region where the intermediate layer is played, There are no layers, and a plurality of longitudinal belt-like connecting portions connected to the main layer laminated on both sides of the intermediate layer are formed along the central axis direction in parallel in the circumferential direction. A laminated preform for biaxial stretch blow molding having a laminated structure in which the layers are divided can be formed. By biaxial stretch blow molding of this laminated preform, the intermediate layer is surrounded by the vertical belt-like connecting portion of the present invention. A synthetic resin laminated housing divided in the direction can be formed.

Hereinafter, a synthetic resin laminated casing, an injection molding apparatus, and a method for molding a laminated preform using the injection molding apparatus according to the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of a synthetic resin laminated casing of the present invention, FIG. 1 is a front view, and FIG. 2 is a cross-sectional plan view taken along line AA in FIG. . This casing is a so-called pressure-resistant PET bottle, which is made of PET resin as a main resin and is used for beverages containing a carbonic acid component. The casing 201 has a mouth tube portion 202, a neck ring 203, a shoulder portion 204, a cylindrical shape. The trunk portion 205 includes a bottom portion 206 that protrudes from a plurality of legs and has a so-called petaloid shape.

In a predetermined height region h2 of this casing 201 (in this embodiment, a height region extending from just below the lower end of the neck ring 203 to just above the upper end of the bottom portion 206), as shown in the plane sectional view of FIG. It has a laminated structure in which an intermediate layer 213 made of polyxylylenediamine adipamide (MXD6 nylon) resin, which is a gas barrier resin, is laminated between an outer layer 211 and an inner layer 212, which are PET resin base layers. Further, as shown in FIG. 2, the intermediate layer 213 includes a plurality (16 in this embodiment) in the circumferential direction of the casing 201 by connecting the outer layer 211 and the inner layer 212 laminated on both sides of the intermediate layer 213. In parallel, the intermediate layer 213 is divided in the circumferential direction by a vertical belt-like connecting portion 214 extending in the vertical direction along the central axis direction.
In the front view of FIG. 1, eight vertical belt-like connecting portions 214 are shown in a height region h <b> 2 that extends from directly below the lower end of the neck ring 203 to immediately above the upper end of the bottom portion 206, and a region in which the intermediate layer 213 is stacked. However, in reality, the intermediate layer 213 and the outer layer 211 or the inner layer 212 as the base layer are in close contact with each other, and are transparent in appearance.

  Here, in this type of conventional pressure-resistant laminated PET bottle, when the cap is removed for drinking, the body wall suddenly collapses and deforms as the pressure inside the housing suddenly decreases. As a result, a shearing force acts between the intermediate layer 213 and the outer layer 211 or the inner layer 212, and the intermediate layer 213 made of nylon resin and the outer layer 211 or inner layer 212 made of PET resin are in close contact, but not bonded. Therefore, delamination occurs, and it is recognized that the delamination is also caused by light scattering or reflection at the delamination portion, and the appearance is impaired.

On the other hand, in the laminated casing 201 of the present embodiment, the effect of the vertical belt-like connecting portion 214 that divides the intermediate layer 213 in the circumferential direction is exhibited, and the delamination can be effectively performed even by the rapid decrease in pressure as described above. It can be suppressed, and the appearance can be maintained in a favorable and transparent state.
The effect of suppressing delamination as described above by the vertical strip connecting portion 214 is that the vertical strip connecting portion in which the laminated structure of the outer layer (base layer) 211 / intermediate layer 213 / inner layer (base layer) 212 is adjacent. Since deformation occurs between short spans such as 214, it is surmised that the deformation is limited in each region and the shearing force acting between the layers is suppressed.

Next, FIGS. 3 and 4 show a laminated preform 101 which is a primary molded product used for biaxial stretch blow molding of the laminated casing 201 of the above embodiment, and FIG. 3 is a partially longitudinal front view, FIG. 4 is a plan sectional view taken along line BB in FIG.
The laminated preform 101 has a test tubular shape made of PET resin as a main material, and includes a mouth tube portion 102, a neck ring 103, a cylindrical body portion 105, and a bottom portion 106.

And when looking at the laminated structure of this preform 101,
In a predetermined height region h1 (in this embodiment, a height region extending from just below the bottom end of the neck ring 103 to just above the top end of the bottom portion 106), as shown in the plane sectional view of FIG. It has a laminated structure in which an intermediate layer 113 made of polyxylylenediamine adipamide (MXD6 nylon) resin that is a gas barrier resin is laminated between an outer layer 111 and an inner layer 112 that are made of a base layer.
As shown in FIG. 4, the intermediate layer 113 includes a plurality (16 in the present embodiment) in the circumferential direction, and the outer layer 111 that is a base layer extending in the longitudinal direction along the central axis direction in parallel. The inner layer 112 is divided in the circumferential direction by a vertical strip connecting portion 114 connected thereto.

Next, an embodiment of an injection molding method of the laminated preform 101 in which the intermediate layer 113 is divided in the circumferential direction by the above-described vertical belt-like connecting portion 114 will be described.
FIGS. 5 to 7 show an embodiment of an injection molding apparatus according to the present invention. FIG. 5 schematically shows the main part thereof, and FIG. 6 is a cross-sectional view showing a state in which the hot runner block 21 is assembled on the upstream side of the multiple nozzle portion 11 in FIG. 1, and FIG. 7 is taken along the line CC in FIG. It is a plane sectional view of the multiple nozzle part 11 shown.

The injection molding apparatus includes resin supply units A and B that individually supply two different types of resins in a molten state, a multiple nozzle unit 11 that stacks two types of molten resins, and a mold 1 that forms a preform. It is what you have.
Among these, the multi-nozzle portion 11 has three layer-forming channels, an annular inner channel 15 and an outer channel 17 that form an inner layer and an outer layer that are base layers, and an annular middle channel 16 that forms an intermediate layer. A cylindrical joining channel 19 is arranged on the downstream side of these three layer forming channels via a junction 18 where the resin flowing in each layer forming channel joins.

Then, in the range from the predetermined position of the middle flow path 16 to the junction 18, the blocking vertical rib piece 16R that crosses the middle flow path 16 is circumferentially divided so as to divide the middle flow path 16 into a plurality of flow paths in the circumferential direction. A plurality are arranged in parallel (16 in this embodiment).
A state in which a plurality of the blocking vertical rib pieces 16R are arranged in parallel in the circumferential direction can be seen from the plan sectional view of FIG. This is provided with a blocking vertical rib piece 16R.

More specifically, as shown in FIG. 7, the annular inner flow path 15, middle flow path 16, and outer flow path 17 are coaxially arranged from the inner side toward the outer side with a shut-off pin 20, a ring mandrel. 24c, 24d, 24e,
The blocking vertical rib piece 16R is inserted into the ring mandrel 24c through the through slit 24cs formed through the peripheral wall so that the middle flow path 16 is in contact with the inner peripheral surface of the outer ring mandrel 24d. The annular middle flow path 16 is divided into a plurality of vertical belt-shaped flow paths in the circumferential direction.

Next, a method (process) for forming the laminated preform 101 shown in FIGS. 3 and 4 using this injection molding apparatus will be described.
The PET resin, which is the main material resin supplied from the resin supply part A, passes through the supply port 22a, the flow path 23a, which is a hot runner, and the nylon resin, which is an intermediate layer resin supplied from the resin supply part B, is supplied to the supply port 22b. The two nozzles 11 are supplied to the multi-nozzle portion 11 at a preset timing through the flow path 23b, and the two kinds of resins are merged in the multi-nozzle portion 11 and filled in the cavity 1a of the mold 1. (See Figure 6)

  For the resin supply units A and B, for example, a screw type extruder or an apparatus such as an accumulator having a plunger attached to the tip of the extruder is used.

  A check valve 25 having a backflow prevention function by a ball valve is attached in the vicinity of a connection point of the flow path 23b to which the intermediate layer resin is supplied to the multiple nozzle portion 11. The check valve 25 can be attached to the multiple nozzle unit 11 side.

The main material resin is distributed and supplied to the annular inner flow path 15 and the outer flow path 17 by the two manifolds 14a1 and 14a2 through the introduction path 12a communicating with the flow path 23a.
Further, the intermediate layer resin is supplied from the manifold 14b to the annular middle flow path 16 through the introduction path 12b communicating with the flow path 23b.

Then, the intermediate layer resin from the middle flow path 16 is caused to flow between the main flow resin from the inner flow path 15 and the outer flow path 17 at the merge point 18, and the main resin is spread over a certain time range in the merge flow path 19. A multilayer molten resin fluid having an intermediate layer resin as a coaxial intermediate layer is formed between and injected into the cavity 1a of the mold 1 and filled.
Here, the intermediate layer resin formed in an annular shape in the middle flow path 16 is divided in the circumferential direction by a plurality of cutoff vertical rib pieces 16R arranged in parallel in the circumferential direction on the downstream side, and this divided In a state, it is laminated between the main material resins.

  FIG. 8 is an example of an injection pattern of the main material resin and the intermediate layer resin for molding the preform 101 shown in FIG. 3, schematically showing the horizontal axis as the time axis and the vertical axis as the injection speed. It is. This injection pattern is one pattern of so-called simultaneous injection molding. FIG. 9 is an explanatory view showing the flow of resin in the mold cavity 1a by this injection pattern.

FIG. 9A shows a state immediately before the E point of the injection pattern, showing a state in which only the main material resin is filled. The injection of the intermediate layer resin starts at the E point, and the main material is between the E and F points. The mold cavity 1a is filled with the intermediate layer resin sandwiched between the resins (see FIG. 8 (b)), the injection of the barrier resin is stopped at the point F, and only the main material resin is filled again. When the process is completed (see FIG. 9C), a preform 101 in which an intermediate layer is laminated in a predetermined height range h1 as shown in FIG. 3 can be obtained.
At this time, the supply of the intermediate layer resin at the points E and F can be started and stopped with high accuracy in a short time by the check valve 25 attached to the flow path 23b to which the intermediate layer resin is supplied. And positioning in the height range h1 can be realized with high accuracy.

As described above, the embodiments of the synthetic resin casing, the injection molding apparatus, and the laminated preform molding method according to the biaxial stretch blow molding of the present invention have been described according to the examples, but the present invention is limited to these examples. Is not to be done.
For example, in the above embodiment, as shown in the plane sectional view of FIG. 2 in the present invention, the laminated structure is two types and three layers, but various laminated structures can be formed as required. FIG. 10 shows another example of the laminated structure of the present invention in a plan sectional view similar to FIG. 2, and shows three laminated structures (a), (b), and (c). ), (B), and (c) each have the following laminated structure.
(A) The substrate layer 211 / intermediate layer 213 / substrate layer 211R using the recycled resin / intermediate layer 213 / substrate layer 211 are three types and five layers from the outside.
(B) From the outside, there are three types and five layers of substrate layer 211 / intermediate layer 213A / substrate layer 211 / other intermediate layer 213B / substrate layer 211.
(C) is three types and four layers of base layer 211 / intermediate layer 213A / other intermediate layer 213B / base layer 211 from the outside.
In these laminated structures, the intermediate layer is divided by the longitudinal band-like connecting portions 114 of the base layer laminated on both sides.

The injection pattern shown in FIG. 9 is for simultaneous injection molding of the main material resin and the intermediate layer resin. However, the main material resin previously injected is temporarily stopped, the intermediate layer resin is injected, and then the main material resin is injected again. A sequential injection pattern for injecting the material resin may be used.
Further, in the above embodiment, the number of the vertical belt-like connecting portions is 16 pieces, but the formation mode such as the number of the vertical belt-like connecting portions or the width is a function based on the purpose of use of the laminated housing, an intermediate layer such as gas barrier properties, Can be determined as appropriate in consideration of the productivity of a preform or a casing using this preform as a primary molded product.
Further, although the casing of the above embodiment is a round casing, it can be a rectangular casing. In this case, since the shape is not isotropic, the formation of a plurality of vertical strip connecting portions along the circumference is provided. The position can be determined in consideration of the angle position at which delamination is likely to occur, not at the same central angle as in the above embodiment.

In the above embodiment, the main resin is made of PET resin and the intermediate layer resin is made of nylon resin. However, various synthetic resins are used in consideration of the purpose of use of the casing, moldability, and functions expected of the intermediate layer. Can be a combination.

According to the present invention, it is possible to easily obtain a casing in which the intermediate layer is divided in the circumferential direction by the vertical belt-like connecting portion, and according to such a casing, it can be used for molding shrinkage, pressure change in the casing, and the like. The resulting delamination between the intermediate layer and the outer layer or the inner layer can be effectively suppressed, and a wide range of usage in fields such as carbonated beverages is expected.

It is a front view which shows one Example of the housing of this invention. It is a plane sectional view shown along the AA line in FIG. It is a partial longitudinal cross-sectional front view which shows the preform used in shape | molding the housing of FIG. FIG. 5 is a cross-sectional plan view taken along line BB in FIG. 3. It is sectional drawing which shows an example of the multiple nozzle of the injection molding apparatus of this invention. It is sectional drawing which shows the state which assembled | attached the hot runner block to the multiple nozzle part of FIG. FIG. 7 is a plan sectional view of a multiple nozzle portion shown along line CC in FIG. 6. It is explanatory drawing which shows an example of the injection pattern for shape | molding the preform of FIG. It is explanatory drawing which shows the filling process of the molten resin to the metal mold cavity by the injection pattern of FIG. It is a plane cross section which shows the other example of the laminated structure in the housing of this invention. It is a front view which shows the prior art example of a laminated housing. It is a partial vertical front view which shows the prior art example of a laminated preform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Mold 1a; Cavity 11; Multiple nozzle part 12a; (Main material resin) introduction path 12b; (Interlayer resin) Introduction path 14a1, 14a2, 14b; Manifold 15; Inner flow path 16; Middle flow path 16R; Rib piece 17; outer channel 18; junction 19; junction 20; shutoff pin 21; hot runner block 22a; (main material resin) supply port 22b; (interlayer resin) supply port 23a; 24c, 24d, 24e; ring mandrel 24cs; through slit 25; check valve A; resin supply part (for main material resin)
B: Resin supply part (for intermediate layer resin)
101, 501; Preform 102, 502; Mouth tube 103, 503; Neck ring 105, 505; Body 106, 506; Bottom 111, 511; Outer layer (base layer)
112, 512; inner layer (base layer)
113, 513; intermediate layer 114; vertical belt-like connecting part h1; height region 201, 601; housing 202, 602; mouthpiece part 203, 603; neck ring 204, 604; 606; bottom portions 211 and 611; outer layer (base layer)
212, 612; inner layer (base layer)
213, 613; intermediate layer 214; vertical belt-like connecting portion h2; height region

Claims (6)

A casing in which a test tube-shaped synthetic resin laminate preform in which at least one intermediate layer is laminated on a base layer made of a main resin is biaxially stretched and blow molded over a predetermined height region (h2). An intermediate layer (213) is laminated between the base layer (211), and there is no intermediate layer (213) in the predetermined height region (h2), and the base layer is laminated on both sides of the intermediate layer (213). A plurality of longitudinal belt-like connecting portions (214) in which the layers (211) are directly welded are extended in the circumferential direction in parallel with the central axis direction, and the longitudinal belt-like connecting portions (214) A synthetic resin laminate case characterized in that the intermediate layer (213) is divided in the circumferential direction by the above. The synthetic resin laminated casing according to claim 1, wherein a portion excluding the mouth tube portion (202) and the bottom portion (206) has a predetermined height region (h2). 3. A synthetic resin laminated housing according to claim 1, wherein the synthetic resin laminated housing has a laminated structure of two types and three layers comprising a main material resin and a gas barrier resin forming the intermediate layer (213). This is for injection-molding a test tubular laminated preform for biaxial stretch blow molding having at least one intermediate layer on a base layer made of a main material resin, and at least the main material resin and the intermediate layer are formed. An injection molding apparatus having two resin supply portions for supplying an intermediate layer resin, a multiple nozzle portion (11) for laminating the main resin and the intermediate layer resin, and a mold (1) for forming a preform. The multiple nozzle part (11) is at least an annular inner channel (15) and an outer channel (17) that form a base layer made of a main material resin, and the inner channel (15) and the outer channel ( 17) has three layer-forming channels of an annular middle channel (16) that is located between and forms an intermediate layer made of an intermediate-layer resin, and at the downstream side of the at least three layer-forming channels, A merge channel (19) is arranged via a merge point (18) where molten resin flowing in each layer formation channel merges, and the intermediate layer resin flows. In a range extending from a predetermined position of the flow path (16) to the confluence (18), a plurality of cut-off longitudinal rib pieces (16R) crossing the middle flow path (16) are arranged in parallel in the circumferential direction, An injection molding apparatus configured to divide the middle flow path (16) into a plurality of flow paths in the circumferential direction by the blocking vertical rib piece (16R). A method for forming a laminated preform for biaxial stretch blow molding using the injection molding apparatus according to claim 4, wherein a main material resin for forming a base layer from one supply part (A) is used as an inner flow path (15). Supply to the outer flow path (17), supply the intermediate layer resin that forms the intermediate layer from the other supply section (B) to the intermediate flow path (16), and block the intermediate layer resin in the intermediate flow path (16) Divided in the circumferential direction by the longitudinal rib pieces (16R), the intermediate layer resin at the junction (18), the main resin from the inner flow path (15) and the outer flow path (17) in a state of being divided in the circumferential direction A laminated molten resin fluid is formed in the joint channel (19), and the laminated molten resin fluid is filled in the mold cavity (1a). Reform molding method. The main material resin forming the base layer is supplied from one supply section (A) at a predetermined pressure or speed for a predetermined time to the inner flow path (15) and the outer flow path (17), and within the predetermined time range. The method for forming a laminated preform for biaxial stretch blow molding according to claim 5, wherein an intermediate layer resin for forming an intermediate layer is simultaneously supplied from another supply part (B) to the intermediate flow path (16) for a certain time.

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