JP2000344253A - Tubular container and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make up a tubular container accurately in an integral form without seams at each of component parts by a method wherein a melted and extruded plastic is cut and after the cut matter is inserted into a metal mold having cavities corresponding to the external surfaces of a nozzle, a shoulder part and a trunk part, the cut matter is processed by compression molding. SOLUTION: On manufacturing a tubular container, a tubular parison, 20 comprising an inner layer 10, a barriering resin intermediate layer 12 and an outer layer 11 is formed first of all by extrusion, and a tubular container forming parison 21 is obtained by cutting the formed matter. Then, the parison 21 is inserted into a female mold 22 which defines the external surface of the tubular container. The female mold 22 has a screw forming part 23, a shoulder forming part 24 and a trunk forming part 25. A male mold 26 which defines the internal surface of the tubular container has a nozzle interior forming part 27, a shoulder interior forming part 28 and a trunk interior forming part 29. The female mold 22 and the male mold 26 are engaged with each other with the parison 21 being interposed in between, and the tubular container 1 is made up by comporessiion molding. Then, the product is taken out after the female and male molds 22 and 26 are separated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube container and a method for manufacturing the same, and more particularly, to a tube container formed by compression molding of molten plastic and having a combination of storage stability of contents, sealing performance by capping and extrusion characteristics. The present invention relates to an excellent tube container and a manufacturing method thereof.

[0002]

2. Description of the Related Art Plastic tube containers are widely used as packaging containers in the fields of foods, pharmaceuticals, toiletry products, medicines, stationery and the like. This tube container has a nozzle portion, a shoulder portion, and a body portion, and has a function of taking out a predetermined amount of contents from the container by pressing the body portion with a finger.

[0003] Further, tube containers made of a multilayer resin are widely used in order to utilize the advantages of various resins and make up for their disadvantages. For example, a gas barrier resin such as an ethylene-vinyl alcohol copolymer is used as an inner / outer surface layer by utilizing the moisture resistance and sanitary properties of a polyolefin resin, while compensating for the polyolefin resin having poor oxygen gas barrier properties. Are used as an intermediate layer, and a tube container in which these are laminated is widely used. In this case, the polyolefin layers provided on both sides of the ethylene-vinyl alcohol copolymer layer also have a complementary action to prevent a decrease in the gas barrier property of the ethylene-vinyl alcohol copolymer due to humidity.

The production of such a plastic tube container is roughly classified into a blow molding method for integrally molding a nozzle portion, a shoulder portion, and a body portion from a parison, a tubular body portion, a nozzle portion, and a shoulder portion. And a fusion molding method in which they are formed separately and fused together.

[0005]

However, in the tube container formed by the blow molding method, since a split mold is used, a parting line is inevitably formed in the formed body corresponding to the joint of the split mold. Since this parting line is a projection, printing is avoided at the parting line, and thus there is a troublesome problem that the tube container needs to be positioned during printing. Further, the nozzle portion formed by blow molding has low dimensional accuracy, and for example, there is a problem that the nozzle portion is wavy.

A parison extruder for forming a tube container is provided with a parison control device, called a parison control, which controls the weight per unit length of each parison. It is almost constant, and it is not always easy to express the function of the nozzle portion and the function of the body portion required for the tube container simultaneously and satisfactorily.

That is, the nozzle portion is required to have high accuracy in terms of sealing performance with the cap and some rigidity in terms of opening and closing torque of the cap. On the other hand, the body part requires a certain degree of flexibility in terms of the extrudability (squeezing property) of the content, and at least the minimum thickness in terms of the preservability (gas barrier property). However, in a tube container formed by blow molding, the nozzle diameter and the body diameter are determined within a certain range while the basis weight is almost constant, so that the rigidity of the nozzle part is insufficient or the thickness of the body is insufficient. Or the squeeze property tends to be unsatisfactory.

Further, in blow molding, a considerable amount of scrap resin is generated due to pinch-off by a split mold, and its reuse is one of the troublesome problems.

On the other hand, in a fusion molding method in which a cylindrical body portion, a nozzle portion and a shoulder portion are formed separately, and these are fused,
Even if a considerable part of the problem of the above blow molding method is solved, a troublesome operation of fusing the nozzle to the body is required, and there is also a problem that productivity is low.

Therefore, an object of the present invention is to provide a nozzle unit,
The shoulder and body are integrally formed without seams, there is no parting line on the outside of the body, high dimensional accuracy and high rigidity for fastening the cap and nozzle for squeeze and preservation The present invention provides a tube container provided with a body portion having an appropriate thickness and a method for producing the tube container. Another object of the present invention is to provide a method for producing the above tube container with a small number of steps and with high productivity.

[0011]

According to the present invention, there are provided a step of melt-extruding a plastic, a step of cutting the extruded product into a predetermined length, and a step corresponding to a nozzle outer surface, a shoulder outer surface, and a body outer surface. A method for producing a tube container, comprising: a step of inserting a cut extrudate into a cavity mold having cavities; and a step of compression-molding the inserted extrudate with a core mold and a cavity mold. Is provided. According to the present invention, in a tube container provided with a body, a shoulder, and a nozzle formed of plastic, the body, the shoulder, and the nozzle are integrally formed by compression molding without a seam. There is provided a tube container characterized in that there is no parting line on the outer surface of the body portion, and the nozzle portion and the body portion are set so that the weight per unit length in the axial direction is substantially different from each other. You. In the present invention, the clearance in the nozzle forming portion between the cavity mold and the core mold and the clearance in the body forming portion between the cavity mold and the core mold can be arbitrarily set, and in particular, the nozzle Independently of the diameter D ₁ of the part and the diameter D _{2 of the} body part, the thickness T ₁ of the nozzle part is 0.50
To 0.90 mm, especially 0.60 to 0.80mm and the body portion of the wall thickness _{T 2} of 0.15 to 0.5 mm, particularly 0.2
It can be set in the range of 5 to 0.40 mm. In the present invention, when the diameter of the nozzle portion is D ₁ , the thickness of the nozzle portion is T ₁ , the diameter of the body portion is D _2, and the thickness of the body portion is T ₂ , the cross-sectional area of each portion is represented by the following formula. _{(1) D 1 × T 1} > D 2 × T 2 ‥ (1) can be set in a range satisfying the which the ratio of the diameter of each _section, D 2 / a ratio of _{D 1} is 2.5 or less, It is particularly effective when the number is 2 or less. Conversely, D ₁ the diameter of the nozzle _portion, T ₁ the thickness of the nozzle _portion, the thickness of the diameter of the body portion D ₂ and the body portion T ₂
, The sectional area of each part can be set in a range satisfying the following expression (2): D ₁ × T ₁ <D ₂ × T ₂ ‥ (2)
That is, it is effective when the ratio of D ₂ / D ₁ is larger than 2.5, especially 3 or more. Further, in the present invention, it is preferable that the vessel wall constituting the tube container has a multilayer structure containing a gas barrier resin as an intermediate layer and a heat sealable resin as an innermost surface.

[0012]

An important feature of the tube container of the present invention is that it is formed by compression molding of a molten resin. That is, the compression molding has the advantage that molding with high mechanical dimensional accuracy of the nozzle portion is possible, and since there is no need to use a split mold, a parting line is not formed on the outer surface of the trunk portion.

Further, the compression molding has a feature that the thickness of the nozzle portion and the thickness of the body portion can be adjusted independently and freely by the clearance between the core mold and the cavity mold. When the nozzle is varied over a relatively wide range, the nozzle has a high rigidity that is desirable for opening and closing the cap, while maintaining a moderate thickness that is desirable in terms of squeezing and gas barrier properties for the body. be able to.

FIG. 1 of the accompanying drawings shows the weight per unit length in the axial direction of each of a nozzle portion, a shoulder portion, and a body portion of a conventional tube container by a blow molding method and an example of the tube container of the present invention. It shows values obtained by actually measuring the ratio (g / mm) and the thickness. According to this measurement result,
Unit weight ratio for blow-molded tube containers (▲)
Is almost constant both in the nozzle portion and the body portion, and it is confirmed that the thickness (●) is reduced by the blown portion of the body portion. On the other hand, in one example of the tube container of the present invention, the unit weight ratio (△) is set to a considerably large value in the nozzle portion, and set to a considerably small value in the body portion, and the thickness ( It is also understood that in (O), the rigidity is improved in the nozzle portion while the squeezing property is improved in the body portion.

In the example shown in FIG. 1, the average weight (g / mm) per unit length in the axial direction of the nozzle portion is A, and the average weight (g / mm) per unit length in the axial direction of the body portion. ) As B, A> B (When the diameter of the nozzle portion is D ₁ , the thickness of the nozzle portion is T ₁ , the diameter of the body portion is D _2, and the thickness of the body portion is T ₂ , A∝ Since D ₁ × T ₁ and B∝D ₂ × T ₂ , this relationship is an example of the above equation (1), and the ratio of the barrel diameter (D ₂ ) / the nozzle diameter (D ₁ ) is 2.5 or less, especially 2
It is effective when the following is true, but it should be understood that the relation of the average weight can be conversely set in a range of A <B (corresponding to the formula (2)). Tube diameter is quite large, especially the body diameter (D ₂ ) /
This is effective for containers having a nozzle diameter (D ₁ ) ratio of greater than 2.5, especially 3 or more. That is, in the latter type of container, in the case of blow molding, the thickness of the body becomes excessively small, and the gas barrier properties and mechanical strength are reduced.
Although production was not possible, in the compression molding of the present invention, it is possible to produce this type of container by adjusting the average weight of the nozzle portion and the body portion.

The compression molding of the present invention has a common point with the blow molding method in that a preform (parison) is formed by extrusion molding of a resin. However, the blow molding method has the above-mentioned problems. However, there is a problem that the mechanical accuracy of the nozzle portion is low, and burr is generated. On the other hand, in the compression molding method, since the outer surface and the inner surface of the nozzle portion are regulated by the cavity mold and the core mold and molding is performed by a compressive force, the mechanical accuracy of the nozzle portion is high, and burrs are generated. In addition, there is an advantage that the thickness of each portion of the nozzle portion can be easily controlled. For this reason, the nozzle portion formed by compression molding has high fastening accuracy with the cap, and enables reliable sealing. Further, in the blow molding method, there is a problem of generation of scrap resin due to pinch-off. However, in the compression molding method of the present invention, all the plastic cut to a predetermined length is used for forming a tube container. No outbreak,
It has advantages in the effective use of resources.

On the other hand, in the compression molding of the present invention, there is a point common to the injection molding method in that the molten resin is molded in a state regulated by the cavity mold and the core mold.
In the case of injection molding, since the resin is injected through the gate portion, the flow orientation is affected by high shearing force. In the case of an ethylene-based polymer most commonly used for an extrusion container, problems such as environmental stress cracking (ESC) are caused. Easy to occur. Further, it is necessary to inject the resin at a high temperature, and therefore, a long time is required for cooling, and there is a problem that the occupation time of the mold becomes long. On the other hand, in the compression molding of the present invention, since the molding is performed by compressing the parison inserted in the cavity mold with the core mold, there is almost no influence of the flow orientation due to the high shear force, and the environmental stress cracking is suppressed. There is an advantage that it is excellent. In addition, molding is easy even when the parison resin temperature is low, and since the molded product is cooled from both the cavity mold and the core mold, the occupation time of the mold can be short, and the productivity is excellent. There is an advantage that.

Further, according to the present invention, since the molding of the nozzle portion, the shoulder portion, and the body portion are performed at one time in an integrated state, and furthermore, it is obtained in a state where the lower end of the body portion serving as a filling port for the contents is opened. The number of steps is extremely small as compared with the conventional tube container manufacturing method, and it is extremely excellent in terms of equipment cost and running cost.

The tube container of the present invention may be formed of a single-layer plastic or a multi-layer plastic. However, when the tube container is molded from a multilayer plastic having a barrier resin as an intermediate layer, the barrier resin intermediate layer can be interposed in all of the nozzle portion, the shoulder portion, and the body portion, and the barrier layer is exposed on the inner surface of the container. Can be prevented, which is convenient.

[Tube Container] In FIG. 2 showing an example of the tube container of the present invention, this container 1 comprises a nozzle part 2, a shoulder part 3 and a body part 4 which are integrally formed. The nozzle part 2 has a discharge port 5 at the tip and a screw 6 for fastening a cap on the outer peripheral surface. Nozzle unit 2 has an outer diameter D ₁ that is reduced in diameter so as to be applicable to a small amount extrusion of the contents, while its wall thickness T ₁ is reliably and easily such moderately unplugging and plugging of the cap The range is such that great rigidity is provided.

The nozzle 2 and the body 4 are smoothly connected via the shoulder 3 on the truncated cone, and the lower end of the body 4 is opened to form an opening 7 for filling the contents. ing. Torso 4
The opening 7 is provided so that the mold can be easily removed from the mold.
It has a tapered shape whose diameter gradually increases toward. Barrel 4 has an average outer diameter D ₂ that is increased diameter compared to the nozzle portion, a range in which the thickness T ₂ are sufficient gas barrier properties and squeeze resistance.

The characteristics of the tube container of the present invention, as already pointed out, independently of the diameter D ₂ of diameter D ₁ and the body portion 4 of the nozzle portion 2, of the nozzle portion 2 of thickness T ₁ and the body portion 4 wall thickness _{T 2}
Is that the can be set freely. That is, since the tube container of the present invention is formed by compression molding, the thickness T
₁ and since the thickness T ₂ of the barrel is strictly defined by the clearance cavity mold and core mold, extremely thin enough thickness thereof when the barrel diameter D ₂ is increased is impaired gas barrier properties or it is of also a situation that the wall thickness decreasing the barrel diameter D ₂ is or is severely thickened enough squeeze is impaired is not caused at all. Diameter ratio (D ₂ /
The relationship between D ₁ ) and the thickness of the nozzle portion (T ₁ ) is shown in FIG. In conventional blow molding tube container, the nozzle portion thickness _{(T 1)} the following equation _{(3) T 1 = (D} 2 / D 1) × T 2 ‥ (3) becomes where the straight line in FIG. 3 is _T 2 = The case of 0.3 mm is shown. That is, when the aperture ratio becomes smaller than 2, the nozzle portion becomes insufficient in thickness, the rigidity is reduced, and the aperture ratio becomes 2.6.
If it exceeds 7, the wall thickness of the nozzle portion becomes excessive and the extrudability decreases, so that the aperture ratio is limited to the range of 2 to 2.67. It has the advantage of not being subject to any restrictions.

As the plastic constituting the tube container of the present invention, any thermoplastic resin conventionally used for producing a plastic tube container can be used.
For example, polyolefin resins, polyester resins, polyamide resins, polycarbonate resins, styrene resins, and the like are used. These may be used alone or in combination.

It is preferable that at least the inner surface of the tube container is formed of an olefin-based resin in terms of sanitary properties and heat sealing properties. As olefin resins, generally, low-, medium-, high-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, propylene-ethylene copolymer, ethylene -Vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ion-crosslinked olefin copolymer (ionomer) and the like. In terms of moldability and thermal adhesiveness of the resin, polyethylene has a melt index (ASTM D1238 1
(90 ° C.) in the range of 0.001 to 2 g / 10 min, and polypropylene having a melt index (ASTM D1238 230 ° C.) in the range of 0.05 to 5 g / 10 min is desirable.

From the viewpoint of the storage stability of the contents, it is advantageous to use a barrier resin, that is, a thermoplastic resin having a low permeability coefficient to various gases and capable of being thermoformed. These barrier resins are selected or used in combination depending on the use of the container.

Examples of the resin having a high barrier property against water vapor include cyclic olefin copolymers and amorphous to low crystalline copolymers of olefins and cyclic olefins (COC).
Is used. As the olefin constituting the copolymer, ethylene is preferred, but propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3
3 to 2 carbon atoms such as -methyl 1-pentene and 1-decene
An α-olefin of 0 is used alone or in combination with ethylene. As the cyclic olefin, basically, an alicyclic hydrocarbon compound having an ethylenically unsaturated bond and a bicyclo ring, particularly a hydrocarbon compound having a bicyclo [2,2,1] hept-2-ene skeleton, for example, Norbornene and tetracyclo include decene. The copolymer (COC) is derived from 50 to 22 mol%, in particular 40 to 22 mol%, of cyclic olefins, particularly preferably norbornene, tetracyclododecene and the balance of ethylene and up to 200 ° C., in particular 150 ° C. It preferably has a glass transition point (Tg) of from about 60 ° C. to about 60 ° C. The molecular weight of the copolymer is not particularly limited, but it is preferable that the copolymer has an intrinsic viscosity [η] of 0.1 to 20 dl / g measured at 135 ° C. in decalin, and has a crystallinity of: It is generally at most 10%, especially at most 5%, as measured by X-ray diffraction. The copolymer (COC) is obtained by random polymerization of an olefin and a cyclic olefin in the presence of a vanadium-based catalyst or a metallocene-based catalyst known per se. A suitable copolymer (COC) is available from Mitsui Petrochemical Co., Ltd. under the trade name APEL.

Examples of the barrier resin against oxygen and aroma components include ethylene-vinyl alcohol copolymers. For example, ethylene-acetic acid having an ethylene content of 20 to 60 mol%, particularly 25 to 50 mol%. A vinyl copolymer having a saponification degree of 96 mol% or more,
A saponified copolymer obtained by saponifying so as to be at least mol% is used. The saponified ethylene-vinyl alcohol copolymer should have a molecular weight sufficient to form a film and is generally 0.01 dL measured at 30 ° C. in a 85:15 phenol: water mixture by weight. /
It is desirable to have a viscosity of at least g, especially at least 0.05 dL / g.

Other examples of the barrier resin having the above-mentioned properties include polyamides having an amide group number of 5 to 50, especially 6 to 20, per 100 carbon atoms; Nylon 6,6, nylon 6 /
6,6 copolymer, meta-xylylene adipamide, nylon 6,10, nylon 11, nylon 12, nylon 1
3. A hexamethylene terephthalamide / isophthalamide copolymer or a blend thereof is used. These polyamides should also have a molecular weight sufficient to form a film, at a concentration of 1.0 g / dl in concentrated sulfuric acid and 30
The relative viscosity (ηrel) measured at a temperature of ° C. is preferably 1.1 or more, particularly 1.5 or more.

Still another example of the barrier resin is a thermoplastic polyester. For example, a polyester derived from a dibasic acid component mainly composed of terephthalic acid and / or isophthalic acid is preferable, and ethylene terephthalate (PET) is preferable. ), Ethylene isophthalate (PE
Preferred are a homopolyester, a copolyester, or a blend thereof mainly comprising at least one ester unit selected from the group consisting of I), butylene terephthalate (PBT) and butylene isophthalate (PBI). The homopolyester or the copolyester should have a molecular weight in the range of film formation, and the intrinsic viscosity [η] measured using a phenol / tetrachloroethane mixed solvent as a solvent is 0.5 to 1.5, especially 0.5 to 1.5.
It is preferably in the range of 6 to 1.5.

In the tube container of the present invention, in many applications, a single-layer structure of a plastic is sufficient, but in the case of a container requiring a high degree of storage, the plastic is made of a gas barrier resin as an intermediate layer. It is preferable to have a multilayer structure containing a heat sealable resin such as an olefin resin on the innermost surface.

FIG. 4 is an enlarged view showing an example of a preferred cross-sectional structure of the tube container of the present invention. This container 1 has an inner layer 10 and an outer layer 11 made of an olefin resin, an intermediate layer 12 made of a barrier resin, Barrier resin intermediate layer 12
It has a multilayer structure including acid-modified olefin-based resin layers 13a and 13b provided between the inner and outer layers 10 and 11. By interposing an acid-modified olefin-based resin layer between the olefin-based resin layer and the barrier resin layer, even when an impact such as dropping is applied, or when an aromatic component in the contents has permeated, A multilayer structure having excellent delamination resistance can be formed.

FIG. 5 is an enlarged view of another example of the preferred cross-sectional structure of the tube container. In FIG. 5, the container 1 has an inner layer 10 and an outer layer 11 made of an olefin resin, an intermediate layer 12 made of a barrier resin, Although having the acid-modified olefin-based resin layers 13a and 13b provided between the barrier resin intermediate layer 12 and the inner and outer layers 10 and 11 is the same as that of FIG. Different first
Is provided with a barrier resin intermediate layer 12 and a second intermediate layer 14. The acid-modified olefin-based resin layer 1 is also provided between the first barrier intermediate layer 12 and the second barrier intermediate layer 14.
3c is provided. The first barrier resin intermediate layer 12 on the inner layer side is, for example, a cyclic olefin copolymer excellent in water vapor barrier properties, and the second intermediate layer 14 is a nylon polymer excellent in barrier properties against flavor components and oxygen. And an ethylene vinyl alcohol copolymer, and this multilayer structure has excellent overall content preservability. Instead of the first barrier resin intermediate layer 12 on the inner layer side, an oxygen absorbent-containing resin layer may be used.

[Production of Tube Container] The production method of the tube container of the present invention comprises the steps of:
Cutting the extruded product into a predetermined length, inserting the cut extruded product into a cavity mold having cavities corresponding to the nozzle outer surface, the shoulder outer surface, and the body outer surface; Compression molding the product with a core mold and a cavity mold.

The preform formed by melt extrusion of a plastic may be a cylindrical parison or a dumpling parison. These parisons may be made of a single-layer resin or a multilayer resin. Is also good.

In FIG. 6 for explaining the first method, the manufacturing process of this nozzle includes a cylindrical parison forming step (A) and a cylindrical parison inserting step (B) into a female mold (cavity mold). ), A step of pressing a male mold (core mold) (C), and a step of removing from the mold (D).

In the step (A) of forming a cylindrical parison, a cylindrical parison 20 comprising an inner layer 10, a barrier resin intermediate layer 12, and an outer layer 11 is formed by extrusion. In this tubular parison 20, the inner layer 10, the barrier resin intermediate layer 1
2. Although the outer layer 11 extends continuously, there may be a portion where the intermediate layer exists at a fixed length and a portion where these intermediate layers are missing. The parison 21 for forming a tube container is obtained by cutting the parison with the cutter 22.

The tube container forming parison 21 maintained at the resin molding temperature is inserted and held in a female mold 22 that defines the outer surface of the tube container, as shown in FIG. 6B. The female mold 22 includes a screw forming part 23, a shoulder forming part 24, and a trunk part forming part 25. On the other hand, the male mold 26 that defines the inner surface of the tube container includes a nozzle inner surface forming portion 27, a shoulder inner surface forming portion 28, and a trunk inner surface forming portion 29. As shown in (C), the female mold 22 and the male mold 26 are engaged with the parison 21 therebetween, so that the tube container 1 is compression molded. The molded tube container 1 is taken out by opening the molds 22 and 26 as shown in FIG.

Referring to FIG. 7 for explaining a method of molding from a dumpling parison, the manufacturing process of this tube container is as follows.
The method comprises a step of forming a dumpling parison (A), a step of inserting the dumpling parison into a female mold (B), a step of pressing a male mold (C), and a step of removing it from the mold (D).

In the step (A) of forming the dumpling parison, the dumpling parison 30 is made of a single-layer plastic, and the dumpling parison 30 is formed by a die or an orifice 31.
And the extrudate is cut by a cutter 22 or the like.

The female mold 22 and the male mold 26 used in FIG.
Are basically the same as those in FIG. The dumpling parison 30 is placed on the female mold 22 as shown in (B), and the female mold 22 and the male mold 26 are placed in the parison 3 as shown in (C).
The nozzle 1 is compression-molded by engaging it with a 0 therebetween. The formed nozzle 1 is taken out by opening the molds 22 and 26 as shown in FIG.
A resin disk 33 remains at the outlet 5 of the nozzle 1 removed from the mold and is closed. In the case of an extrusion container requiring strict sealing performance, the resin disk 33 can be left as it is, and the outlet is opened by, for example, turning the cap removed from the nozzle upside down and provided on the opposite side of the screw. This can be performed by piercing the opening protrusion into the resin disk.

Of course, it is also possible to manufacture a nozzle having an open nozzle outlet. In this case, the nozzle 1 shown in FIG. By punching out the disk 33 by using, a container nozzle having an open outlet is obtained.

Referring to FIG. 8 for explaining a method of molding from a multi-layered dumpling parison, the tube container is manufactured by a multi-layered dumpling parison forming step (A) and a step of inserting the dumpling parison into a female mold ( B), a step of pressing the male mold (C), and a step of removing the mold from the mold (D).

In the step (A) of forming a multi-layer dumpling parison, the dumpling parison 30 comprises a core 35 of a gas barrier resin to be an intermediate layer and a shell 34 of an olefin resin to be an inner and outer layer. Parison 30
Is extruded through a die or an orifice 31 and the extrudate is cut by a cutter 22 or the like. The female mold 22 and the male mold 26 used in FIG. 8 are basically the same as those in FIG. The multilayer dumpling parison 30 is placed on the female mold 22 as shown in (B), and the female mold 22 and the male mold 26 are engaged with each other with the parison 30 interposed therebetween as shown in (C). The nozzle 1 is compression molded. Molded nozzle 1
Is taken out by opening the molds 22 and 26 as shown in FIG.

In the production of the tube container by compression molding according to the present invention, the average weight per unit length in the axial direction of the nozzle portion (g / mm) A and the average weight per unit length in the axial direction of the body portion (g / mm) g / mm) B can be freely set, and even when the ratio of the body diameter (D ₂ ) / nozzle diameter (D ₁ ) is greatly changed, the thickness (T ₁ ) of the nozzle portion is also large. In addition, the thickness (T ₂ ) of the body can be secured in a necessary and sufficient range.

The thickness (T ₁ ) of the nozzle portion is generally 0.50 to 0.5, although it differs depending on the type and shape (nozzle diameter D ₁ , body diameter D ₂ ) of the resin constituting the tube container. It is preferably in the range of 0.90 mm, especially 0.60 to 0.80 mm, while the body thickness (T ₂ ) is 0.15
It is preferably in the range of 0.5 to 0.5 mm, especially 0.25 to 0.40 mm. If the thickness of the nozzle portion is less than the above range, the rigidity of the nozzle portion is reduced, so that the opening and closing of the cap may not be performed smoothly, or the airtightness of the contents at the time of sealing may be impaired. On the other hand, even if the thickness of the nozzle portion exceeds the above range, there is no particular advantage and the amount of resin increases, which is not economically preferable. Further, if the thickness of the body is less than the above range, the mechanical strength of the body is reduced, or the gas barrier property is reduced, so that it is not preferable. Absent.

When the ratio of the body diameter (D ₂ ) / nozzle diameter (D ₁ ) is 2 or less, it is effective to satisfy the above expression (1), and the body diameter (D ₂ ) / nozzle diameter is effective. When the ratio of (D ₁ ) is 3 or more, it is effective to satisfy Expression (2). In addition, the taper angle of the body is 3 in terms of die-cutting.
It is preferably in the range of 15 to 15 °, particularly 5 to 10 °.

[0047]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

[Material Structure] As shown in FIG. 4, the multilayer parisons used in the examples and comparative examples have the following three types of five layers (inner layer / adhesive layer / barrier layer / adhesive layer / outer layer). Things. Inner and outer layer: LDPE DND2450 manufactured by Nippon Unicar Barrier layer: APEL8008 manufactured by Mitsui Chemicals Adhesive layer: VLDPE acid-modified resin

[Molding Method] In the molding by this method, the tube container is molded by using the apparatus shown in FIG. 6 for the cylindrical parison, and the apparatus shown in FIG. went. The molding conditions are as follows. Resin temperature 200 ° C (measured at the extruder outlet) Molding tool Taper angle 5 ° Molding force 500kgf Holding time 5 seconds In the comparative example, a tube container was molded by a direct blow method known per se. . Resin temperature 200 ° C (however, measured at the extruder outlet) Blow molding pressure 35 kg / cm ²

[Experimental Example 1] Tube forming test (1) Nozzle outer diameter D1 = φ9 (unit: mm, same hereafter) Body outer diameter D2 = φ15, φ20, φ30 Body thickness T2 = 0.3, 0 .4 Tube length 120

Table 1 below shows the measurement results of the thickness (T1) of the nozzle portion.

Table 1 [Measured value (mm) of nozzle part thickness (T1)] Molding method Body part thickness Body part outer diameter (D2, mm) (T2, mm) φ15 φ20 φ30 Example 1 This method 0. 3 Molded to an arbitrary thickness of 0.6 to 0.8 Example 2 The present method 0.4 Molded to an arbitrary thickness of 0.6 to 0.8 Comparative Example 1 Direc 0.3 0.50 0.67 1. 0 Toblow Insufficient wall thickness Good Excessive wall thickness Comparative Example 2 Direc 0.4 0.67 0.89 1.33 Toblow Good Slightly excessive wall thickness Excessive wall thickness

A preferable range of the thickness (T1) of the nozzle portion is as follows.
0.6 to 0.8 mm. When T1 is less than 0.6 mm, the rigidity of the nozzle portion is insufficient, resulting in poor sealing. On the other hand, when T1 exceeds 0.8 mm, the rigidity increases from the nozzle portion to the shoulder portion, and the nozzle opening (inner diameter) increases. This is because the squeezability is reduced due to the narrowing. Therefore, as is clear from the above test results, according to the present invention, the thickness (T1) of the nozzle portion can be formed to an arbitrary thickness within a favorable range of 0.6 to 0.8 mm, which is extremely advantageous. You can see that.

[Experimental Example 2] Tube forming test (2) Nozzle outer diameter D1 = φ9 Nozzle wall thickness T1 = 0.6, 0.8 Body outer diameter D2 = φ15, φ20, φ30 Tube length 120

Table 2 shows the measurement results of the thickness (T2) of the trunk.
Shown in

[Measurement value (mm) of body part thickness (T2)] Molding method Nozzle part thickness Body part outer diameter (D2, mm) (T1, mm) φ15 φ20 φ30 Example 3 This method 0. 6 Molded to an arbitrary thickness of 0.2 to 0.3 Example 4 This method 0.8 Molded to an arbitrary thickness of 0.2 to 0.3 Comparative Example 3 Direc 0.6 0.36 0.27 0. 18 Throwing slightly excessive thickness good Slightly insufficient thickness Comparative Example 4 Direc 0.8 0.48 0.36 0.24 Trouble thick excessively slightly excessive thickness good

The preferable range of the wall thickness (T2) of the body is 0.1 mm.
2 to 0.3 mm. If T2 is less than 0.2 mm, the rigidity of the body is insufficient, and the shape retention is inferior. On the other hand, if T2 exceeds 0.3 mm, the rigidity of the body is increased and the squeezing property is reduced. is there. Therefore, as is clear from the above test results, according to the present invention, the thickness (T2) of the trunk portion
Can be formed into an arbitrary thickness within a favorable range of 0.2 to 0.3 mm, which is extremely advantageous.

[0056]

According to the present invention, there are provided a step of melt-extruding a plastic, a step of cutting this extrudate to a predetermined length, and cavities corresponding to the outer surface of the nozzle, the outer surface of the shoulder and the outer surface of the body. The step of inserting the cut extrudate into the cavity mold, and the step of compression-molding the inserted extrudate with the core mold and the cavity mold, by producing a tube container, the nozzle portion, the shoulder portion And the body is integrally formed without seams, there is no parting line on the outside of the body, high dimensional accuracy and a large rigid nozzle for fastening the cap and moderate for squeezing and storage There is an advantage that a tube container having a body portion having a large thickness can be manufactured, and further, this tube container can be manufactured with a small number of steps and with high productivity.

[Brief description of the drawings]

FIG. 1 shows a nozzle section of a tube container according to a conventional blow molding method and an example of a tube container according to the present invention.
It is the graph which showed the value which measured the weight ratio (g / mm) per unit length of axial direction, and thickness about each of a shoulder part and a trunk | drum.

FIG. 2 is a side view of a tube container according to the present invention.

FIG. 3 is a graph showing a relationship between a nozzle wall thickness and a ratio of a diameter of a tube container formed by blow molding.

FIG. 4 is a cross-sectional view showing a cross-sectional configuration of an example of a multi-layered tube container according to the present invention.

FIG. 5 is a cross-sectional view showing a cross-sectional configuration of another example of a multi-layered tube container according to the present invention.

FIG. 6 is an explanatory view showing one example of a manufacturing process of the tube container according to the present invention.

FIG. 7 is an explanatory view showing another example of the manufacturing process of the tube container according to the present invention.

FIG. 8 is an explanatory view showing still another example of the manufacturing process of the tube container according to the present invention.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3E065 AA01 BA12 BB03 CA09 CA11 DA04 DB01 FA01 FA11 FA12 HA02 HA06 4F208 AA03C AA10 AG07 AH55 AR12 MA05 MB01 MC03 MG02 MG04 MG22 MH19 MJ05 MJ10

Claims (15)

[Claims] 1. A step of melt-extruding a plastic, a step of cutting the extruded product to a predetermined length,
From the step of inserting the cut extrudate into a cavity mold having cavities corresponding to the shoulder outer surface and the trunk outer surface, and from the step of compression molding the inserted extrudate with a core mold and a cavity mold A method for producing a tube container. 2. A clearance in a nozzle forming portion between a cavity mold and a core mold and a clearance in a body forming portion between a cavity mold and a core mold can be arbitrarily set. 3. The method for producing a tube container according to item 1. Wherein independently of the diameter _{D 2} of diameter _{D 1} and the body portion of the nozzle portion, the thickness _{T 1} of the nozzle portion is 0.50 to 0.90m
preparation of the tube container according to claim 1, the thickness T ₂ of the m and the body portion and sets the range of 0.15 to 0.5 mm. 4. The nozzle having a diameter of D₁The thickness of the nozzle
T₁, The diameter of the trunk is D ₂And the thickness of the trunk₂And
Equation (1) D₁× T₁> D₂× T₂ 2. The method according to claim 1, wherein ‥ (1) is satisfied.
3. The method for producing a tube container according to 3. 5. The method for producing a tube container according to claim 4, wherein the ratio D ₂ / D ₁ is 2.5 or less. 6. When the diameter of the nozzle portion is D ₁ , the thickness of the nozzle portion is T ₁ , the diameter of the body portion is D _2, and the thickness of the body portion is T ₂ , the following formula (2) D ₁ × The method for producing a tube container according to claim 1, wherein T ₁ <D ₂ × T ₂ ‥ (2) is satisfied. 7. The method of claim 6, wherein the ratio D ₂ / D ₁ is greater than 2.5. 8. The method according to claim 1, wherein the plastic has a multilayer structure containing a gas barrier resin as an intermediate layer and a heat sealing resin as an innermost surface. 9. A tube container having a body, a shoulder, and a nozzle formed of plastic, wherein the body,
The shoulder portion and the nozzle portion are integrally formed by compression molding without a seam, there is no parting line at least on the outer surface of the body portion, and the weight of the nozzle portion and the body portion are substantially the same per unit length in the axial direction. A tube container characterized by being set differently. 10. independently of the diameter _{D 2} of diameter _{D 1} and the body portion of the nozzle portion, the thickness _{T 1} of the nozzle portion is 0.50 to 0.90
tube container according to claim 9, the thickness T ₂ of the mm and body portion, characterized in that it is set in the range of 0.15 to 0.5 mm. 11. When the diameter of the nozzle portion is D ₁ , the thickness of the nozzle portion is T ₁ , the diameter of the body portion is D _2, and the thickness of the body portion is T ₂ , the following formula (1): D ₁ × The tube container according to claim 9, wherein T ₁ > D ₂ × T ₂ ‥ (1). 12. The tube container according to claim 11, wherein a ratio of D ₂ / D ₁ is 2.5 or less. 13. When the diameter of the nozzle portion is D ₁ , the thickness of the nozzle portion is T ₁ , the diameter of the body portion is D _2, and the thickness of the body portion is T ₂ , the following formula (2): D ₁ × The tube container according to claim 1, wherein T ₁ <D ₂ × T ₂ ‥ (2) is satisfied. 14. The tube container according to claim 13, wherein the ratio D ₂ / D ₁ is greater than 2.5. 15. The tube according to claim 9, wherein the vessel wall constituting the tube container has a multilayer structure containing a gas-barrier resin as an intermediate layer and a heat-sealing resin as an innermost surface. container.