JPH02162027A - Multilayer hollow vessel with streak for see-through and die head for multilayer coextruding - Google Patents

Abstract

PURPOSE:To enable the level height of content to be seen from outside and to enable the colored resin with sufficient color effect at its residual part to be used by forming a partial wall of a periphery having higher light-penerating power than that of neighboring part into a longitudinal streak-existing in the whole eight of a vessel. CONSTITUTION:The multilayer hollow vessel 1 with the streak for see-through is a plastic hollow vessel whose whole periphery is enclosed with the wall 6 of a multilayer structure in which an inner layer 2, a barrier layer 4 and an outer layer 3 are laminated with the layers of adhesive intervening between each two layers, and the longitudinal streak 7 for see-through existing in its whole height is provided on one side of the vessel. The barrier layer 4 is the material with small permeability to oxygen, and is composed of e.g. ethylene vinyl alcohol copolymer, and then its jointless whole periphery is made with the resin of uniform composition. At the residual part 8 being the greater part of the vessel wall, both inner layer 2 and outer layer 3 are composed of opaque colored resin 11, i.e. the natural resin colored into white with titanium white. On one hand, at the streak 7 for seel-through, the inner layer 2 and the outer layer 3 are composed of natural resin 12 of same material as the colored resin 11, and at the part of the streak 7 for see-through, the level height of the content in the vessel may be seen from the outside.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to hollow plastic containers used as packaging containers for shampoos, liquid detergents, cosmetics, and other liquid contents, and multilayer coextrusion for manufacturing the same. It concerns die heads.

[Prior Art] Plastic hollow containers made of colored resin are used as packaging containers for shampoos, liquid detergents, cosmetics, and other liquid contents.

[Problems to be Solved by the Invention] While such a hollow container made of colored resin has an aesthetic effect due to its beautiful colors, it is not possible to see through the liquid content, and the amount of the content is larger than the outside in both the production and consumption stages. There were some inconveniences that were not obvious at first glance.

In order to eliminate this drawback, it is possible to mold a portion of the circumference of a container made of colored resin into a vertical band shape using another transparent resin, but in this case, the boundary surface of different resin flows may be The molecules are formed extending from the inner surface to the outer surface in the thickness direction of the container wall, and the orientation of the molecules in this part is almost aligned in the height direction of the container, resulting in other problems such as a decrease in strength and an increase in oxygen permeability. A problem arises.

This invention was made in view of the above circumstances, and it has a color effect using opaque colored resin of any color and a see-through function that allows you to see through the liquid content from the outside no matter what height it is. It is an object of the present invention to provide a multilayer hollow container with see-through lines that has both the above properties and does not impair the barrier properties against oxygen intrusion, and a die head for multilayer coextrusion that can be used for manufacturing the same.

[Means for Solving the Problems] Corresponding to this object, a multi-layer hollow container with see-through lines of the first invention is provided, which is located between an inner layer and an outer layer, and between the inner layer and the outer layer, and a barrier layer made of a resin having a lower oxygen permeability than the outer layer. The multilayer coextrusion die head of the second invention is characterized in that at least one of the outer layers has a higher light transmittance than the adjacent portion, and the multilayer coextrusion die head of the second invention is arranged upstream of an extrusion die for forming a hollow body and A die head for supplying a multilayer molten resin in which an inner layer resin, an intermediate layer resin, and an outer layer resin are laminated in the width direction of the annular slit into an annular slit of an extrusion die, the inner layer resin, the intermediate layer resin, and the outer layer resin and tube-shaped passages each having an annular cross section for the inner layer resin passage, and the intermediate layer resin passage joins the inner layer resin passage from the outside to form an annular merging portion, and downstream thereof, the intermediate layer resin passage joins the inner layer resin passage from the outside. The passages of the outer layer resin merge from the outside to form an annular merging section, and furthermore, the outer layer resin portion merges with the passage of the outer layer resin and corresponds to at least one portion on the circumference of the annular slit. Another resin passageway (A) capable of supplying resin having different physical properties from the remaining outer layer resin part, and an inner layer resin part that merges with the inner layer resin passage and corresponds to the first part on the circumference of the annular slit. The present invention is characterized in that it includes at least one of further resin passages (B) capable of supplying a resin having physical properties different from those of the remaining inner layer resin portion.

[Function] The multilayer hollow container with transparent lines configured as described above has the following features:
At least a portion of the wall on the periphery has a higher light transmittance than the adjacent portion, so by forming this portion into a vertical line that spans the entire height of the container, the content liquid can be passed through the wall from the outside. To make it possible to see through the inner layer resin and the outer layer resin, while making it possible to use a colored resin with a sufficient color effect for the inner layer resin and the outer layer resin, although the remaining part cannot be seen through.

In addition, in the see-through striped portion, the barrier layer with low oxygen permeability among the resin layers constituting the wall is formed continuously over the entire circumference, so this barrier layer has
Since a boundary surface in the wall thickness direction cannot be formed due to the welding of different resin flows as described above, the molecules in this part are oriented in a free direction almost perpendicular to the wall thickness direction and are intertwined with each other, which is not what this resin layer should originally have. Does not impair oxygen barrier properties.

In addition, in the multilayer coextrusion die head configured in this way, a colored resin is continuously applied to the inner layer resin passage and an outer layer resin passage, and a resin with low M element permeability is continuously applied to the intermediate layer resin passage. and at the same time, to at least one of the backs of [other resin passage (A)] and [further other resin passage (B) J of the multilayer coextrusion die head,
When a resin having a higher light transmittance than the colored resin is continuously supplied, a resin layer having a lower oxygen transmittance is sandwiched between an inner resin layer and an outer resin layer in the annular slit of the extrusion die for forming a hollow body. The important thing here is that at least one part of the periphery of the die, at least one of the inner resin layer and the outer resin layer is colored S4 resin that occupies the remaining part. Therefore, in the parison extruded from the die, parts with high light transmittance are formed in a continuous vertical line shape, and the intermediate layer has a continuous resin flow over the entire circumference. The hollow container, which is formed without a boundary surface and is made by blow-molding this parison, also has vertical stripes with high light transmittance over the entire height of the container, and the intermediate layer has a continuous I layer along the entire circumference. #4 A multilayer hollow container with viewing striations formed without the interface of the fat stream and providing a barrier layer against oxygen is formed.

[Example] Hereinafter, details of the present invention will be explained with reference to drawings showing an example.

In FIGS. 1, 2, and 3, reference numeral 1 denotes a multilayer hollow container with streaks for viewing.

The multilayer hollow container 1 with transparent lines is a plastic hollow container surrounded by a wall 6 of a multilayer structure in which an inner layer 2, a barrier layer 4, and an outer layer 3 are laminated in order with a contact layer 5 in between. A vertical line-shaped see-through line 7 extending over the entire height of the container is provided on one side.

Here, the barrier layer 4 is made of a material with low oxygen permeability, such as EVOH (ethylene-vinyl alcohol copolymer).
The entire circumference is made of resin of uniform composition extruded from one extruder ta (not shown) - a phenomenon that tends to occur at the joints of different resin flows, where different types of resin are seamlessly formed. The molding is done in such a way that the molecular chains in both resin streams do not clearly separate to either side of the interface and become oriented along the interface, where the strength decreases or oxygen permeates easily. ing.

On the other hand, in the inner layer 2 and the outer layer 3, the constituent resins are different between the see-through filament 7 and the remaining portion 8.

That is, in the remaining portion 8 that occupies most of the container wall, both the inner layer 2 and the outer layer 3 are made of opaque colored resin 11-.
For example, it is made of natural resins such as polypropylene and polyethylene that are colored white with titanium white.
On the other hand, in the transparent line 7, the inner layer B2 and the outer layer 3 are made of natural wood 1 and 'i12, which are the same material as the colored resin 11, that is, polypropylene or polyethylene, and the transparent line 7 is made of a container from the outside. It is possible to see through the contents of the liquid art dealer.

Regarding the cross-sectional shape of the 120 layers of natural resin forming the see-through filament 7, as shown in FIG. , the appearance can be improved by making it slightly inclined with respect to the thickness direction.

In the above-described multilayer hollow container 1 with transparent lines 1, a layer of natural resin 12 is formed on both the inner layer 2 and the outer layer 3 of the transparent lines 7. As shown in the multilayer hollow container 1a with see-through lines shown in FIG.

Next, a die head for multilayer coextrusion will be explained.

In FIGS. 6 and 7, 21 is a die head for multilayer coextrusion. To the die for multilayer coextrusion The rad 21 is disposed upstream of the extrusion die 22 for forming a hollow body, and is inserted into the annular slit 23 of the extrusion die 22, as shown in FIG.
A multilayer molten resin 28 in which an inner layer resin 24, an intermediate layer resin 25, and an outer layer resin 26 are laminated in the width direction 27 of the annular slit 23.
It is intended to supply The multilayer molten resin 28 is for blow molding to obtain the multilayer hollow container 1 with see-through lines, and the inner layer resin 24 on one side of the same as above.
a and the outer layer resin 26a are the remaining portions 24b and 2, respectively.
It is made of a material having higher light transmittance than the resin constituting 6b, for example, natural resin 12.

The die head 21 for multilayer coextrusion has an inner layer resin passage 31,
An adhesive resin passage 32, an intermediate layer resin passage 33, an adhesive resin passage 34, and an outer layer resin passage 35 are each formed into a tube shape with an annular cross section. That is, the die head 21 for multilayer coextrusion includes a cylindrical spider 36 at the center, and coaxial cylindrical sleeves 37, 38, 40, 41 and an outer mold 42 located sequentially outside the spider 36. The upper part has seven flange 43, 44, 45, 46, 47 respectively at the upper end, and these flanges are successively stacked and fitted into each other such that the lower surface of the former touches the upper surface of the latter, and the lowermost 7 flange 47 overlaps the upper surface of the outer mold 42 to define their mutual radial positional relationship, and as a result, each passage 31 is formed as a gap having an annular cross section between them in the lower part whose outer diameter is slightly smaller than that of the upper part. .32, 33, 34, and 35 are formed.

Each lower end 32a of the passage 32.33, 34.35.

33a, 34a, and 35a are inclined diagonally inward and downward, and open at the outer periphery of the spider 36, respectively.

That is, a lower end 32a from the outside of the passage 31 forms an annular merging part around the outer periphery of the spider 36, and a lower end 33a from the outside joins the passage 31 downstream from the outer periphery of the spider 36, forming an annular merging part. , Similarly, the lower end portion 34a downstream thereof and the lower end portion 35a downstream thereof sequentially merge from the outside to form an annular merging portion around the outer periphery of the spider 36,
The downstream part 48 of the merging passage where all these passages 31, 32, 33, 34, 35 are joined forms a tube shape with an annular cross section on the outer periphery of the lower part of the spider 36, and then continues into the spider 36 with the tube shape of an annular cross section. Tapered part 3 at the lower end of
The diameter is reduced along the line 6a to reach the annular slit 23 of the extrusion die 22.

At the upper end of each passage 31, 32, 34, 35, the inner wall surface of each passage projects inward in the shape of a semicircular longitudinal section, that is, it goes around the outer peripheral surface of the inner sleeve or spider that constitutes the inner wall surface of each passage. A groove with a semicircular arc cross section is formed in the grooves, forming annular resin supply passages 51, 52, 53, 54, and each of these resin supply passages has a straight resin supply passage 51a at one place on its circumference. , 52a, 53a, 54a are connected,
These are also connected to respective extruders (not shown).

The upper end of the passage 33 similarly forms a resin supply passage 50, and the resin supply passage 50 is connected to an extruder (not shown).

The upper end of the resin passage 31.35 and the resin supply passage 51a
, 54a, the other resin supply paths 55(B) and 56(A) join together at positions 180° opposite to the connection points with the resin supply paths 55(B) and 54a, respectively.
These pass resin from another extruder (not shown) to passage 3.
1.35 can be fed.

The structure of the confluence of the resin passage 35 and the resin supply path 56 (A>) is shown in FIGS. 8 and 9. In other words, a guide wall 57 is provided at this confluence. It is connected to the tip of the i-body 58 forming the resin supply path 56 and defines the position and cross-sectional shape that the resin flow from the resin supply path 56 occupies in the upper end 35b of the resin path 35, The outer surface 57a is curved so as to straddle the resin supply path 54 and the resin passage 35, and smoothly changes the direction of the resin flow from the direction 61 in the resin supply path 54 to the direction 62 in the resin passage 35. On the other hand,
The inner surface 57b is connected to the inner surface of the tube body 58, and its lower end is parallel to the direction 62 (see FIG. 8) so that the resin supplied through the resin supply path 56 is sent out in the direction 62 (see FIG. 8). As shown in the figure, it is turned diagonally inward.

The structure of the junction between the resin passage 31 and the resin supply passage 55 (B) is similar to the structure of the junction between the resin passage 34 and the resin supply passage 56 described above.

When forming the multilayer molten resin 28 using the multilayer coextrusion die head 21 configured as described above, colored resin is supplied to the resin supply channels 51a and 54a, and barrier layer phase resin is supplied to the resin channel 50. , resin supply paths 52a, 53a
The adhesive resin 10 is supplied to the resin supply path 55.5.
6, a material with high light transmittance, such as a natural resin, may be supplied.

In order to mold the multilayer hollow space 51a with transparent lines,
Multilayer coextrusion die head 2 shown in FIGS. 11 and 12
1a is used. The multilayer coextrusion die head 21a lacks a resin supply path 55 that merges with the inner layer resin path 31.

[Effects of the Invention] According to the multilayer coextrusion die head 21 configured as described above, it is possible to obtain a seamless multilayer molten resin 28 of different resin flows in the intermediate layer, and the intermediate layer is made of a resin with low oxygen permeability. The multilayer hollow container 1 with see-through lines obtained by blow molding this structure does not impair the oxygen barrier effect.

As is clear from the above explanation, the present invention combines the color effect using opaque colored resin of any color and the transparent function that allows the liquid content to be seen through from the outside no matter what height the liquid level is. Furthermore, it is possible to obtain a multilayer hollow container with see-through lines that does not impair the barrier properties against oxygen intrusion, and a die head for multilayer coextrusion that can be used for manufacturing the same.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a multilayer hollow container with see-through lines according to an embodiment of the present invention, FIG. 2 is an explanatory cross-sectional end view of the multi-layer hollow container with see-through lines shown in FIG. 3 is an enlarged view of section C in FIG. 2, FIG. 4 is an explanatory cross-sectional end view of a multilayer hollow container with see-through lines according to another embodiment of the present invention, and FIG. 5 is an enlarged view of section D in FIG. 4. An enlarged view, FIG. 6 is a vertical cross-sectional explanatory view showing a die head for multilayer coextrusion according to an embodiment of the present invention, FIG. 7 is a plan view of the die head for multilayer coextrusion shown in FIG. 6, and FIG. An explanatory longitudinal cross-sectional view of the interior of the confluence of the resin passage and the resin passage (A) taken along a plane in the tangential direction, FIG. 9 is a sectional view of rX-IXX in FIG. 8, and FIG. A cross-sectional explanatory diagram showing a multilayer molten resin formed by a multilayer coextrusion die head shown in FIG.
FIG. 11 is an explanatory longitudinal cross-sectional view showing a multilayer coextrusion die head for molding the multilayer hollow container with see-through lines shown in FIG. 4, and FIG. 12 is a longitudinal cross-sectional view showing the multilayer coextrusion die head shown in FIG. FIG.

Claims (1)

[Claims] (1) A plastic having a peripheral wall having a multilayer structure in which an inner layer, an outer layer, and a barrier layer made of a resin located between the inner layer and the outer layer and made of a resin having a lower oxygen permeability than the inner layer and the outer layer are laminated. A multilayer hollow container with streaks for see-through, wherein at least a portion of the peripheral wall in the circumferential direction is characterized in that at least one of the inner layer and the outer layer constituting the peripheral wall has a higher light transmittance than an adjacent portion. Container (2) is disposed upstream of an extrusion die for molding a hollow body, and carries a multilayer molten resin in which an inner layer resin, an intermediate layer resin, and an outer layer resin are laminated in the width direction of the annular slit into the annular slit of the extrusion die. The die head is provided with tube-shaped passages each having an annular cross section for the inner layer resin, the intermediate layer resin, and the outer layer resin, and the inner layer resin passage is provided with a tube-shaped passage for the inner layer resin, the intermediate layer resin, and the outer layer resin, and the inner layer resin passage is provided with The passages of the intermediate layer resin merge to form an annular merging section, and the passages of the outer layer resin merge from the outside downstream thereof to form an annular merging section, and furthermore, the passages of the outer layer resin merge with the passage of the outer layer resin. The outer layer resin portion corresponding to at least one portion on the circumference of the annular slit is connected to another resin passageway (A) capable of supplying a resin having different physical properties from the remaining outer layer resin portion and the inner layer resin passageway. Further, another resin channel (
A multilayer coextrusion die head comprising at least one of B)