JPS61108541A - Manufacture of pressure-resistant vessel made of paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to the technical field of a manufacturing process of a low-pressure paper pressure-resistant container for filling and storing beverages such as beer.

The invention of this application is based on a body having a circular cross-section, in which a material made of a valve material is covered with a film having gas barrier properties at least on the surface in contact with a stored pressurized fluid such as beer, and This invention relates to a method for manufacturing a pressure-resistant paper container in which lids are joined together, and in particular, the upper and lower lids are formed by heating and pressurizing a nonwoven mat made of paper pulp containing synthetic pulp to form a pillow shape. The skirt of the ring-shaped flange is joined to the inner end of the body with a circular cross section, and the lid surface is integrally extended inward from the skirt at an obtuse angle, and the lid surface is integrally formed at the joint between the body and the lid body. The joint is heated until the resin constituting the fitting welding surface is in a welded state, and the joint is heated uniformly over the entire joint surface only from the outer surface of the container at the joint in a direction perpendicular to the joint surface. Applying a pressing force to join the bodies, and furthermore, apply pressure to both ends of the body, or
A paper whose opening at one end is bent outward and expanded, and then an upper cover and/or a lower cover is inserted and fitted, and then the cover body is adhered to the body by heat welding in the same manner as described above. This invention relates to a method for manufacturing a pressure-resistant container made of aluminum.

<Prior Art> As is well known, glass bottles have traditionally been used as storage containers for beverages in distributed products, but they are inconvenient to handle and require many additional steps for inspection and cleaning before reuse. In addition to requiring a large amount of space in terms of facilities, they also pose a risk of breakage, so they are being replaced by metal cans, which are superior in pressure resistance and safety.

Incidentally, although the seed metal cans have advantages such as being lightweight and easy to manufacture, and requiring almost no recycling process, the problem of so-called empty can pollution due to disposable use that does not require re-collection cannot be ignored. Therefore, in the third generation, polyester bottles such as 11 PET bottles started to be on the market, and they are excellent in terms of ease of molding and variety of designs.

However, with the exception of some PET bottles, these types of polyester bottles also cause various problems such as high heat generation when incinerated and environmental pollution due to disposable use. This has become a bottleneck in distribution.

On the other hand, for example, milk containers have advantages such as water resistance and ease of incineration due to being disposable, so-called paper containers have started to appear on the secondary market after the practical application of waterproofness through resin coating has been demonstrated. It has come to be widely adopted as it is highly effective in terms of low cost and ease of handling.

For beverages that do not have pressure, such as alcoholic beverages and juice seasonings, pressure resistance and leak resistance are hardly required of the paper container material, so the only problem is the gas barrier property against the stored liquid. However, carbonated drinks such as beer and cider are actually filled into containers with an internal pressure of 2 to 5 KO/12 G, although the pressure is not so high due to the conditions at which they are consumed.

Therefore, containers for filling and storing carbonated beverages are generally required to have sufficient pressure resistance, gas barrier properties, and waterproofness to withstand this, and as a secondary requirement, ease of processing and low cost are also required. This is what is required.

As mentioned above, although the practicality of paper containers for milk, seasonings, etc. has been proven in terms of waterproofness, in terms of gas barrier properties and pressure resistance, paper containers do not come close. Until now, the empirical results have not been sufficient, which has prevented its practical application in the secondary market.

Here, as disclosed in the inventor's and applicant's many prior patent inventions for paper pressure containers, we have determined the gas barrier properties and pressure resistance through numerous repeated experiments and theoretical analysis. has reached the stage where it can be put to practical use through research and development on the selection of materials and structure.

By the way, basically speaking about pressure vessels, their shape and structure require that most of the parts that come into contact with pressure fluid be curved, as a basic condition for pressure resistance. It has no choice but to consist of three lids, an upper and lower lid, and the shape and structure of each of them poses various difficulties in practical use.

In particular, the upper and lower lids must be joined to the body with a circular cross section in a post-process, so we fully guarantee the pressure resistance and sealing performance of the stored pressurized liquid, as well as the design of the product. The problem was that various difficulties were involved in the processing process.

The lid body is connected to the body having a circular cross section by means such as welding at the inner surfaces of the upper and lower ends of the body through parallel ring-shaped flanges (hereinafter referred to as skirts). This is the common technique up to now.

In the aforementioned prior invention, the inventors proposed two shapes l1Ij as shown in FIG. 1.2 as examples of preferable shapes and structures of paper pressure containers.

Incidentally, FIG. 1 also shows a paper pressure-resistant container based on an embodiment of the invention of this application.

<Problems to be Solved by the Invention> The major difference between the embodiments shown in the two figures lies in the shape and structure of the lower lid.

That is, in the embodiment shown in FIG. 1, a spherical shell-shaped lid surface 5 integrally extending inwardly with respect to the skirt 4 of the lower lid 3 for the body 2 of the paper container 1 is attached to the skirt 4. It is integrally formed and extended at an obtuse angle.

On the other hand, in the embodiment of the paper container 1' shown in FIG. A lid surface 5' is formed in a convex shape to the outside of the container.

Therefore, as in the embodiment shown in FIG. 2, when a steep angle bending process such as folding from the skirt 4' to the lid surface 5' is required, since the container 1' is made of paper, the lower lid Fiber breakage is likely to occur in the pulp material of 3', and when the internal pressure of the stored liquid acts on this, the sharply bent part will buckle and deform due to the internal pressure. As a result, there is a drawback that the joint strength between the body 2 and the skirt 4' is reduced.

Therefore, in the embodiment of FIG. 2, in order to strengthen the bent portion, a reinforcing ring made of resin or the same material as the lid body is attached to the inner surface of the skirt 4' of the lower lid 3', as shown in the figure. Some kind of reinforcing means, such as charging and setting 6, is required.

Therefore, considering the formability and pressure-resistant strength of the lower lid 3', the lower lid 3 of the container 1 shown in FIG. 1 is better than the container 1' of FIG. This means that the structure is more preferable.

When manufacturing the container 1 having the shape shown in FIG. 1, the upper lid 7 is usually first fitted onto the upper end surface of the paper body 2 prepared in advance, and then the skirt 8 of the body 2 and the upper lid 7 is fitted.
Each joint surface is welded by a predetermined means such as a thermal welding method, an ultrasonic welding method, or a high frequency induction heat welding method via a resin film laminated in advance thereon.

j In this way, if one or both ends of the body 2 are open, attach a suitable welding jig to the welding part inside the container 1 to weld the upper lid 1 and the body 2. Since it can be inserted, there is no substantial problem during welding.

However, there were two major obstacles when joining the lower cover 3 to the lower part of the fuselage 2 via the skirt 4.

That is, the first obstacle is that it is not as easy to insert the lower cover 3 into the lower end of the body 2 as the upper cover 1.

In containers where airtightness is extremely important, such as the container covered by the invention of this application, sufficient attention must be paid to the fitting of the joint between the body 2 and the lower lid 3. It is most preferable that the inner circumferential diameter of the body 2 and the outer circumferential diameter of the skirt 4 of the lid body 3 match mathematically, but if this is not the case, the lower lid 3
It is preferable to make the outer circumferential diameter of the skirt 4 slightly larger than the inner diameter of the body 2 in order to improve fitting performance.

In such a case, the upper M7, which is already inserted first into the upper end of the body 2, is inserted by moving from the lower side above the spherical lid surface, given its shape, as shown in Fig. 3. However, as shown in FIG. 4, it was extremely difficult to insert and fit the lower M3 because it had to be inserted through the skirt 4.

Next, the second obstacle is the adhesion of the skirt 4 to the body 2 after the lower lid 3 is fitted.

In II shown in FIG. 2, the inner side of the skirt 4' will be exposed to the outside of the container 1' for the shape of the lower part ii 3', so any of the welding methods described above can be adopted. In the shape and structure of the lower lid 3 in the embodiment shown in Figure 1, the skirt 4 is positioned inside the container 1, so it is extremely difficult to support the joint to the body 2 from the side of the skirt 4 inside the container 1. It means that it will become.

In particular, when using an ultrasonic welding method or a high frequency induction heating welding method, which requires support from both sides of the joint, there is a problem in that this joining method cannot be practically adopted.

In addition, in the heat welding method, for example, as in the embodiment shown in FIG. 5, which the inventors exemplified in another prior invention, a predetermined jig 10 is inserted through a drinking spout 9 formed in the upper lid 7, and the Welding is also possible through cooperation between the roller 11 and the outer roller 12 of the body 2.
However, it is difficult to handle for industrial purposes. This is a problem that can be expected to cause many problems due to the complexity of the process.

Because of such a neck, even if the paper pressure container shown in Fig. 1 is proposed as a "product" and invented as a structure, it is almost impossible to embody it and put it into practice. Even if it were implemented, there was a problem that it could not be commercialized due to cost.

<Object of the invention> The object of the invention of this application is to provide a paper pressure-resistant container for filling and storing pressurized fluids such as carbonated drinks such as beer and cider, which is basically developed to be practically possible as a "product" based on the above-mentioned prior art. The problem of joining the upper and lower lids to both inner ends of the fuselage, which is a bottleneck in the practical use of , an excellent paper pressure container that sufficiently increases the pressure resistance of the joint between the body and lid of the container, thereby ensuring the practicality of the paper pressure container, thereby benefiting the field of container utilization in the distribution industry. The present invention aims to provide a method for manufacturing a pressure-resistant container.

<Background of the Invention> The inventors determined that ultrasonic welding, high frequency induction heating welding, etc. are undesirable for the reasons mentioned above, and researched a technical solution by employing thermal welding.

However, when using the thermal welding method, in order to heat the welding surface and achieve perfect weldability, for example, as shown in FIG. It is necessary to press the welded surface and firmly fix it.

If this pressing and fixing operation is not performed from both the inside and outside sides, 1. Even if the mating surface has excellent fit with the conventional technology, the joint surface will undergo thermal deformation during heating, resulting in a decrease in the fit. As a result, there is a risk of defective welding, which significantly reduces the reliability of containers and the like in terms of their sealability.

Therefore, the inventors focused on a nonwoven mat, which is one material for the lid of a paper pressure container.

The details of this non-woven fabric mat and its molding are one of the applicant's earlier inventions (Japanese Patent Laid-Open No. 59-847
It is disclosed in detail in the invention disclosed in No. 33) that the shape structure of the lid of a container obtained by heating and press-molding a nonwoven fabric mat made from paper pulp containing synthetic pulp has rigidity and Taking advantage of the advantages of excellent strength and virtually no wrinkles on the skirt, which is the joint surface with the body, the conventional approach to heat welding was changed.

That is, when welding a non-woven mat lid having such a shape and physical properties to the body, as described above, the welding surface can be removed from one side without pressing the welding surface from both the inside and outside of the container. For example, we have proceeded with development to achieve extremely good welding by uniformly performing a suppression operation over the entire welding surface only from the outside, and have obtained good data.

<Means/effects for solving the problems> In order to solve the problems mentioned above, the invention of this application, which is based on the above-mentioned claims and is in line with the above-mentioned purpose, is as follows.

In other words, the shape and structure of the paper pressure container basically consists of a body with a circular cross section, a spherical shell-shaped upper lid, and a lower lid joined to the body. The contact surface is made of polyvinylidene chloride, polyacrylonitrile,
Alternatively, it may be covered with a resin film having gas barrier properties such as a saponified ethylene-vinyl acetate copolymer resin, or a laminated film in which a heat-fusible film such as polyethylene is laminated to improve weldability. It is a paper cylinder with a circular cross section, and as mentioned above, it is generally extremely difficult to insert the lid into the joint surface with the body through its skirt, so In the step of inserting and fitting the upper cover and/or lower cover to the inner surface of either end, the end of the cover insertion part of the body is bent or curled outward in advance to form a guide flange. Form it in one piece.

On the other hand, the upper and lower lids are made by heating, pressurizing, and molding a non-woven fabric mat made of paper pulp containing synthetic pulp, and as mentioned above, at least the surfaces in contact with the pressurized fluid are provided with a gas barrier. - It is covered with a resin film having properties or a laminated film made by laminating a film such as polyethylene thereon, and has a ring-shaped flange skirt that fits and adheres to the body. A spherical shell-like lid surface integrally extending inwardly with the skirt is formed so as to extend integrally with the skirt at an obtuse angle.

Therefore, when joining the lid to the body, by inserting the lid from the open end of the body and through the guide of the guide flange, the insertion and fitting of the lid is facilitated. The joint is heated until the resin constituting the fitting welding surface between the body and the lid becomes welded without any damage to the body and lid skirt, and the joint is made only from the outer surface of the container at the joint. By uniformly applying pressing force over the entire welding surface in a direction perpendicular to the surface, the welding of the joint is made more secure, and the reliability of the container is significantly improved. <Embodiment - Configuration> Next, an embodiment of the invention of this application will be described below with reference to FIG. 6 and subsequent figures. Incidentally, parts having the same features as those in FIGS. 1 to 5 will be described using the same reference numerals.

FIG. 6 shows the basic shape of the paper pressure container 11 during the manufacture of the paper pressure container 1 shown in FIG. It consists of three bodies: a cylindrical body 2, an approximately bowl-shaped spherical upper lid 7 with a spherical radius of 14IaIllR, and a lower lid 3 (substantially, a cap is attached to the drinking spout 9 of the upper lid 7). Top lid 7
A filling and pouring spout forming the drinking spout 9 is formed in a predetermined manner in the center of the upper surface, and the lid surface 7' forms a gently curved surface to form a welding surface that fits into the body 2. The skirt 8 of the ring-shaped flange has a cylindrical shape with a height of 10 mm, and has a shoulder formed by bending and forming a gentle inward obtuse angle as shown in the figure with respect to the lid surface 1'. Part 1
3 and is integrally molded.

Also, the lower lid 3 has a lid surface 5' that projects downward but has a gently curved surface, and is different from the upper lid 1 except that it is formed so as not to have the drinking spout 9. are substantially the same, and from the ring-shaped flange skirt 4 which is abutted and welded to the body 2 as described above, a lid surface 5 having a gently curved surface forms a shoulder portion 13 of the folded portion. It is integrally formed and extends inwardly at an obtuse angle.

As mentioned above, the upper lid 7 and the lower lid 3 are molded products made by warm press-molding a paper pulp non-woven fabric mat containing 30% by weight of polyethylene synthetic valve and solidifying it by heating and cooling, as shown in the figure. It is molded into a bowl shape, and its inner and outer surfaces are covered with a barrier laminated film as described above.

In order to provide barrier properties, the body 2 is coated with a polyethylene/polypylidene chloride/polyenlene gas barrier laminate film (for example, manufactured by Asahi Kasei Corporation, the applicant) on the inner and outer surfaces of the paperboard. It is formed into a cylindrical paper tube made of laminated paper (trade name ``Varyalon'').

The structure of the body 2, the upper cover 7, and the lower cover 3 as materials and their molding are explained in detail in other prior inventions of the same applicant.

Next, in the manufacturing method of the paper pressure container 1, first, as shown in FIG. The T-guide flange 14 is formed by bending and expanding at an angle of .

Note that the guide flange 14 has its end portion heated to 100 to 150°C.
It can be formed more easily by preheating to an appropriate temperature.

Although there are no particular limitations on the bending width and bending angle of the guide flange 14, it is preferable that the bending width is 2-51I11 and the bending angle is 30-60'.

Depending on the design, the id lunge 14 may be curved in cross-sectional shape.

Next, as shown in FIG. 8, the upper cover 1 is inserted upward into the body 2 through its guide flange 14 and is pushed into the upper end of the body 2, and then the lower cover 3 is inserted into the body 2 as well. 2 through the guide flange 14, and, as shown in FIG. 6, is fitted into a predetermined position in the lower part of the body 2, and the three parts are integrated.

Then, the upper and lower lids 1.3 and 15.16 of the body 2
is heated with hot air at 150 to 1 kgO<0>C, and after the resin film on the mating and welding surface reaches the welding temperature, immediately proceed to step 8.9.
Apparatus 1 for applying pressing force divided into multiple parts in the same direction as shown in Fig. 10
7. Set each skirt of the upper and lower lids 7.3 to 8.
A uniform pressing force is applied to the welding surface of No. 4 for 15 seconds only from the outside of the container in a direction perpendicular to the welding surface, and the upper and lower lids 11.3 are firmly welded to the body 2. do.

In this case, the driving of each jig 11' of the pressing force applying device 17 is appropriately controlled by an actuator such as a pneumatic cylinder or a hydraulic cylinder, and is synchronously operated from the outside.

In this way, the container 1 shown in FIG.
' will be commercialized as is.

In addition, the guide flange 14 at the lower end of the body 2, which is bent outward to guide the insertion of the upper and lower lids 7.3, has a pressing surface of each jig 17' aligned with this guide, as shown in FIG. If the flange 14 is also contacted and pressed from the outside,
It is also possible to return the straight cylindrical body 2 to its original state before forming the flange 14, and the paper pressure-resistant container 1 shown in FIG. 1 can also be realized as a product.

Although FIG. 8 shows the joining method for the lower part 1[3, the joining method for the upper cover 1 can be performed in the same way.

In the above-described embodiment, the guide flange 14 is formed by bending and forming the lower end of the body 2.
4 shows a mode in which the upper cover 7 is inserted and then the bottom cover 3. Of course, the upper end of the body 2 is bent and formed to form a guide flange in the same way, and the lower cover 3 is inserted and lowered first. Then, the upper lid 7 is inserted, or the upper and lower ends of the body 2 are bent together to form a guide flange, and the upper lid 7 and the lower M3 are inserted from their respective corresponding ends. A method of insertion can also be adopted.

Alternatively, a pressing force applying device having pressing force applying device rollers 18, 18, . . . shown in FIGS. 8, 9, and 10 may be used.

In this pressing force applying device, pressing force is uniformly applied to the entire joint surface of the joint portion while each O-ruler 18 rotates.

In addition, in the experiment according to the example, the mating adhesive surface was heated with hot air from outside the container until the resin on the adhesive surface became welded, and then a pressing force application device was used to perform a suppressing operation. It was definitely fixed after a while.

Data has been obtained that it is advantageous to keep the pressing surface of the pressing force applying device at room temperature or a temperature lower than that in order to speed up the cooling fixing time.

In addition, as another embodiment, the pressing surface of the pressing force applying device can be heated to a predetermined temperature, and the heating and pressing operation can be performed simultaneously. In this case, after the heating and pressing operation, the container joint part is heated. It may be cooled by leaving it in the air or by setting it in another pressing force application device maintained at a low temperature.

After the upper and lower lid bodies 7.3 are fitted and bonded to the body 2, a drinking spout 9 made of high-density polyethylene is inserted into the upper lid opening.
is attached by heat welding.

In actual use, a carbonated beverage is filled into the container, and the drinking spout 9 is completely sealed with an aluminum cap.

As an experiment, after filling the carbon dioxide gas-water mixture and sealing the cap, the container was moved to a constant temperature room at 40°C and left in this state for 10 days, but the container not only broke, but also contained gas and gas due to poor adhesion.
No water leaks were observed, and the storage condition remained good.

The pressure inside the container at this time was 3.5 to 9/cm2G.

The embodiment shown in FIGS. 12 and 13 is also an embodiment of the container 1' of the invention of this application, in which the body 2' is formed in a tapered shape with a small diameter on the upper side, and the lid surface extends from the skirt 13 of the upper lid 7. 7' is slightly larger than the obtuse angle of the above-mentioned embodiment, and the obtuse angle of the bending from the skirt 4 of the lower base 3 to the lid surface 3' is slightly steeper than that of the above-mentioned embodiment. Compared to the above-mentioned embodiments, there is no difficulty in manufacturing, and the material is broken at the bending part, there are pinholes in the polyethylene film laminate covering, sealing defects are poor, and the gas barrier properties are poor. There is no risk that the functions of the other devices will be impaired.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments, and that various embodiments can be adopted, and the container is not only for filling beer, but also for containing sweeteners such as cider. It can also be applied to carbonated drinks, etc., and the filling and pouring spout can be of a short cylindrical protruding type (or a cut-off opening shape is also acceptable), and it can also be used with a ring-shaped flange of the upper and lower lid materials or a flat lid. It is possible to adopt an embodiment in which the surface does not need to be smooth, and the lid surface does not need to be three-dimensionally formed into a smooth curved surface.

<Effects of the Invention> As described above, according to the invention of this application, although the pressure is not basically high pressure like other inventions previously filed by the applicant, the pressure resistance is not high in a container filled with a predetermined low pressure pressure drink. It is fully guaranteed, its gas barrier properties are also ensured, and
The excellent effect is that the waterproofness of the material is maintained, and in addition, a paper pressure-resistant container that is easy to process and mold can be obtained. .

In addition, since the material is pulp material, it is essentially difficult to mold its three-dimensional curved surface, but it is made to consist of three bodies, the body material and the upper and lower lid materials. By forming a smooth bend from the ring-shaped flange-shaped skirt of the lid material to each lid surface, the molded container has a lid that protrudes in the axial direction at its upper and lower ends. Not only does it have the excellent effect of increasing the internal volume and being formed into the optimal shape for a pressure-resistant structure, but it also has the advantage of having a lid surface that is at an obtuse angle from the ring-shaped flange skirt to the lid surface. This provides an excellent effect in that the pulp material of the material is not broken and therefore there is no risk of deterioration in pressure resistance.

Furthermore, no pinholes or the like are formed in the barrier film covering the material, which provides excellent sealing properties, good waterproof properties, and gas barrier properties. The effect is produced.

By forming an outward-opening guy 1 flange in at least one end opening of the body during the container manufacturing process, it becomes possible to insert the lid body into the body through the skirt of the type-shaped lid body, which is the most preferable body and lid body. The excellent effect of obtaining a bonded structure is achieved.

For this reason, it is possible to apply the pressing force necessary for and ensuring the joining only from the outside of the fuselage due to the structure, and it is also possible to simplify the equipment and reduce costs.

Therefore, the invention of this application can easily and reliably connect the body and the lid, which has been considered extremely difficult in the past, when manufacturing a pressure-resistant paper container with a shape and structure having excellent characteristics as described above. This has been made possible, and it can be put to practical use without causing any major industrial problems, and has the extremely excellent effect of ensuring the practicality of paper pressure containers. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a paper pressure container according to the invention of this application, Fig. 2 is a longitudinal sectional view of a conventional paper pressure resistant container, and Fig. 3 is a sectional view illustrating the process of inserting and fitting the lid into the body. 4 is a cross-sectional view of the conventional joining process of the lid to the body, FIG. 5 is a longitudinal cross-sectional view of the conventional welding process of joining the body and the lid, and FIG. 6 is a paper-made example of the embodiment of the invention of this application. Vertical cross-sectional view of the pressure vessel during the equipment process,
Fig. 7 is a sectional view of the body of Fig. 6, Fig. 8 is a sectional view of the pressing force applying device and the container, Figs. 9 and 10 are plan views of the pressing force application state of the embodiment, and Fig. 11 is another A plan view of the pressing force applying device, and FIGS. 12 and 13 are an explanatory sectional view and a perspective view corresponding to FIG. 1 of another embodiment. 2.2'... Body, 3.7... Lid body, 4.8... Ring-shaped flange (skirt), 1.1'
1'...-Paper pressure container, 16...Joint part, 14...Guide flange 5th factor 1 and Figure 11-2'/ Figure 12 Figure 13

Claims (2)

[Claims] (1) A method for manufacturing a paper pressure container in which a pulp lid is inserted into the end opening of a paper body with a circular cross section, and the ring-shaped flange is attached to the inner surface of the body by heat welding. Manufacture of a paper pressure-resistant container, characterized in that when the lid is inserted into the end opening and the joint is heated and welded, a pressing force is uniformly applied only from the outside of the joint. Method. (2) A method for manufacturing a pressure-resistant paper container, in which a pulp lid is inserted into the end opening of a paper body with a circular cross section, and the ring-shaped flange is attached to the inner surface of the body by heat welding. The end opening is expanded outward to form a guide flange, the lid body is inserted into the end opening through the guide flange, and the outside of the joint is heated and welded. A method for manufacturing a pressure-resistant paper container, characterized in that a pressing force is uniformly applied only from the inside.