JP5392658B2 - Laminated blow housing - Google Patents

Description

The present invention relates to a synthetic resin laminated blow housing in which a multilayer parison having a barrier layer that exhibits a barrier function inside an outer layer is molded by a direct blow molding method.

  For example, Patent Document 1 describes an invention about a blow housing made of synthetic resin. Forms the outer shell, which is responsible for basic properties such as moldability, strength, rigidity, etc., inside the outer layer, for gases such as oxygen, ingredients of drugs and cosmetics, moisture, fragrance ingredients, etc. By making a laminated blow housing with a barrier layer that demonstrates the barrier function and the function of preventing the adsorption of these components, the basic performance that cannot be achieved with a single layer and the advanced barrier function can be exhibited together. Can do.

Patent Document 2 describes an invention relating to a die for multilayer blow molding for molding a multilayer parison, which is a precursor of a laminated blow housing as described above, by coextrusion molding.

WO00 / 69627 Japanese Patent Laid-Open No. 10-128836

  Here, as an example of a casing having a barrier function, for example, a barrier layer made of nylon resin or ethylene vinyl alcohol copolymer (EVOH) resin is laminated on an outer layer made of polyethylene (PE) resin to have a high gas barrier function. Laminated blow housings are used, but when direct blow molding this type of housing, the bottom end of the co-extruded multilayer parison is cut off by the pinch-off part of the mold to form the bottom seal part However, the nylon resin and EVOH resin forming the barrier layer have relatively low viscoelasticity, and therefore, the biting property due to the pinch-off portion is poor and the productivity is lowered, and therefore, burrs are generated and the appearance is impaired. There are problems such as.

An object of the present invention is to effectively prevent the problem relating to the biting property due to the pinch-off portion of the mold in the laminated blow housing in which the barrier layer is laminated inside the outer layer from the viewpoint of the layer configuration.

Among the means for solving the above technical problems, the main configuration of the present invention is as follows.
It is molded by blow molding of an extruded cylindrical multilayer parison, and has a bottom part in which a mouth part, a shoulder part, a body part, and a seal part by a pinch-off of the parison are formed, and is predetermined inside an outer layer that forms an outer shell. In a laminated blow housing configured by laminating a barrier layer that exhibits the barrier function of
A gradation region related to the layer thickness of the barrier layer in which the layer thickness of the barrier layer decreases toward the seal portion reaches the bottom seal portion and decreases toward the seal portion.

  In the above configuration, the configuration related to the gradation area, such as the extent to which the gradation area is arranged or the layer thickness is reduced, is the barrier function achieved by the barrier layer, the moldability of the gradation area Then, it can be determined in consideration of the effect of the gradation area, that is, the improvement effect related to the parison cut-off property.

The gradation region related to the layer thickness of the barrier layer of the laminated blow housing is provided with the gradation region related to the layer thickness of the barrier layer in a portion corresponding to the gradation region of the casing of the cylindrical multilayer parison which is the precursor. Can be formed.
Further, when a multilayer parison is formed by coextrusion molding using a die for multilayer blow molding, the flow rate of the barrier layer resin in the flow path of the barrier layer resin forming the barrier layer is changed at a predetermined timing, or By starting or stopping the flow, the gradation region related to the thickness of the barrier layer can be disposed in the multilayer parison.

Here, the adjustment of the flow amount of the resin for the barrier layer, or the start and shut-off of the flow, for example, a valve such as a ball valve or a sprue valve attached to the supply flow path for supplying the molten resin to the flow path of the barrier layer resin It can be carried out by controlling the mechanism and the shutter mechanism, or adjusting the discharge pressure by an extruder, an accumulator or the like.
Since the molten resin has viscoelastic properties, it also has a stringing effect. Even if the flow of the resin for the barrier layer is started or stopped at a predetermined timing, as a result, the layer thickness of the barrier layer is changed to a gradation. be able to.

And according to the main configuration above,
By arranging a gradation area that reaches the bottom seal part, the barrier layer thickness is reduced in the vicinity of the seal part, the influence of the barrier layer is reduced, and the cut-off property at the time of pinch-off of the parison is maintained well. It is possible to eliminate problems such as a decrease in productivity and a loss of appearance due to burrs.

  Another configuration of the present invention is that, in the main configuration described above, the seal portion that is the end of the gradation region reaching the seal portion is a non-barrier region in which no barrier layer is laminated.

  The above configuration is a region in which the barrier layer is not further laminated by further reducing the thickness of the barrier layer at the end of the gradation region, and such a configuration uses a multilayer blow molding die. When a multilayer parison is formed by coextrusion molding, the barrier layer resin is flowed by appropriate means such as the valve mechanism and the shutter mechanism as described above in the flow path of the barrier layer resin that forms the barrier layer at a predetermined timing. This can be done by starting or stopping.

And by making the sealing part into a non-barrier region where the barrier layer is not laminated with the above configuration, the problem relating to the biting property at the time of pinch-off of the mouth tube part and the bottom part due to the lamination of the barrier layer can be solved more reliably. can do.

Since the present invention has the above-described configuration, the following effects can be obtained.
That is, in the laminated blow housing having the main configuration of the present invention,
By arranging a gradation area that reaches the bottom seal part, the barrier layer thickness at the seal part can be reduced, the influence of the barrier layer can be reduced, and the cutting ability during pinch-off can be maintained well. In addition, problems caused by stacking barrier layers such as a decrease in productivity and a loss of appearance due to burrs can be solved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a first embodiment of a first embodiment of a housing of the present invention. It is a bottom view of the housing of FIG. It is a side view which cuts down and shows the 2nd example of the 2nd example of the frame of the present invention. It is a schematic explanatory drawing which shows the shaping | molding state of a multilayer parison.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 show a first embodiment of a laminated blow housing of the present invention. FIG. 1 is a side view showing a part of the laminated blow case, and FIG. 2 is a bottom view. This housing 1 has a cylindrical mouth tube portion 2, a shoulder portion 3, a cylindrical body portion 4 that expands in a taper shape from the top to the center height position, and a bottom portion 5. The bottom portion 5 has a parison. The seal part 6 formed at the time of pinch-off is located in the radial direction.

  This casing 1 is formed by laminating a barrier layer 12 inside an outer layer 11 forming an outer shell through an adhesive layer 13 over the entire height range (see an enlarged view of the trunk portion 4 in the figure). The outer layer 11 is made of a high-density PE resin, the adhesive layer 13 is made of a polyolefin-based adhesive resin, and the barrier layer 12 is made of an EVOH resin having high gas barrier properties.

  In the portion reaching the seal portion 6 of the bottom portion 5, as shown in the enlarged view in the vicinity of the seal portion 6 in the figure, a gradation region in which the layer thickness of the barrier layer 12 decreases toward the seal portion 6 in a gradation shape. G1 is disposed.

  Then, by arranging the gradation region G1 reaching the seal portion 6 as described above, the thickness of the barrier layer 12 made of EVOH resin is extremely thin in the vicinity of the seal portion 6, and the influence of the barrier layer is reduced. In addition, it was possible to maintain a good cut-off property at the time of pinch-off of the parison, and to solve problems such as a decrease in productivity and a loss of appearance due to burrs.

  Next, FIG. 4 is a schematic explanatory view showing a molded state of the multilayer parison, and particularly for schematically explaining a method for forming the gradation region G1 of the casing 1 shown in FIG. The state which extruded the cylindrical multilayer parison 20 from the die | dye 32 for multilayer extrusion molding between the split molds 31 for blow molding in a state is shown.

The multilayer parison 20 is formed by laminating a barrier layer 22 made of EVOH resin via an adhesive layer (not shown) on an outer layer 21 made of high-density PE resin.
A gradation region Gp1 related to the thickness of the barrier layer 22 is disposed at a position corresponding to the gradation region G1 of the casing 1 at the lower end.
Then, the gradation region Gp1 of the parison 20 is closed in the state where the gradation region Gp1 of the parison 20 is positioned near the pinch-off portion 34 of the split die 31, and the air is blown from the upper end opening portion as shown in FIG. The casing 1 provided with such a gradation region G1 can be formed.

  Here, the multi-layer parison 20 includes at least three annular layer forming channels arranged in the order of the barrier layer channel, the adhesive layer channel, and the outer layer channel from the inside, and downstream of the layer forming channel. Extrusion is performed using a die for multi-layer extrusion, which is provided with a confluence channel located through a junction, but the opening of the valve mechanism or shutter mechanism is adjusted at a predetermined timing, or the discharge pressure by an accumulator, etc. As described above, the gradation region Gp1 of the parison 20 can be formed by adjusting the flow amount of the barrier layer resin.

  Next, FIG. 3 is a side view showing a part of the second embodiment of the laminated blow housing of the present invention in a longitudinal section. This housing 1 is a variation of the housing 1 of the first embodiment shown in FIG. 1, the gradation region G1 reaching the seal portion 6 is a non-barrier region where the barrier layer 12 is not laminated in a narrow region extending from the immediate vicinity of the seal portion 6 to the seal portion 6 as compared with the case of FIG. S is characteristic.

In the multilayer parison 20 molding method described above, such a layer configuration is achieved by opening the valve mechanism and shutter mechanism for adjusting the flow of the resin for the barrier layer from the closed state to the open state at a predetermined timing. can do.
And, by making the narrow area from the immediate part of the seal part 6 to the seal part 6 in this way limited to the non-barrier area S, without significantly impairing the barrier property, the biting property at the time of pinch-off of the parison, It can be held well and satisfactorily.

As mentioned above, although embodiment of this invention was described along the Example, the effect of this invention is not limited to these Examples.
For example, the combination of the resin used for the outer layer and the resin used for the barrier layer can be selected in various ways depending on the purpose of use, taking into account the function that the barrier layer exhibits, the moldability of the multilayer parison, the blow moldability, etc. be able to.

  In addition, the configuration relating to the gradation area, such as the extent to which the gradation area is arranged or the extent to which the thickness of the barrier layer is reduced including the non-barrier area at the end, It can be determined in consideration of functions such as barrier properties and light-shielding properties achieved by the layer, formability of the gradation region, and the degree of the effect of the gradation region, that is, the degree of improvement effect related to the parison cut-off property.

In addition, the barrier layer is not limited to the gas barrier function described in the above embodiment, and the barrier function and the adsorption of these components to components such as drugs, cosmetic ingredients, moisture, and fragrance ingredients according to the purpose of use. It is possible to select a barrier layer that exhibits a barrier function that exhibits a function to prevent the occurrence of the above.
In addition, layers having other functions can be stacked as necessary.

The laminated blow housing of the present invention is as described above, and by effectively disposing the gradation region related to the layer thickness of the barrier layer, the problem relating to the cut-off property at the time of pinch-off of the parison is effectively solved. It is expected to be used in a wide range of applications as a housing that requires barrier properties.

DESCRIPTION OF SYMBOLS 1,100; Housing 2,102; Mouth part 3,103; Shoulder part 4,104; Trunk part 5,105; Bottom part 6,106; Seal part 11,111; Outer layer 12,112; Layer 20; Parison 21; Outer layer 22; Barrier layer 31; Split mold 32; Die 33; Mouth 34; Pinch-off part G1; Gradation area S;

Claims (2)

The bottom part (5) formed by blow molding of an extruded cylindrical multilayer parison and formed with a mouth part (2), a shoulder part (3), a body part (4), and a seal part (6) by a pinch-off of the parison. ), And a laminated blow housing configured by laminating a barrier layer (12) exhibiting a predetermined barrier function inside an outer layer (11) forming an outer shell, wherein the bottom (5) A gradation region (G1) related to the layer thickness of the barrier layer (12) in which the layer thickness of the barrier layer (12) decreases in a gradation shape toward the seal portion (6) is arranged toward the seal portion (6). A laminated blow housing made of synthetic resin. The laminated blow bowl according to claim 1, wherein the seal portion (6) which is an end portion of the gradation region (G1) reaching the seal portion (6) is a non-barrier region (S) where the barrier layer (12) is not laminated. body

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