JPS59174444A - Pressure-resisting 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 The present invention relates to a pressure-resistant paper container suitable for containers for beer, carbonated drinks, etc.

Paper containers are similar to those seen in milk or fruit juice cartons.
As is well known, it is used in large quantities in the market. However, containers for beer, carbonated drinks, etc. must be able to resist the internal pressure of carbon dioxide gas and prevent the permeation of carbon dioxide gas, so glass bottles and metal cans such as aluminum have traditionally been used. . More recently, blow-molded polyester bottles have also been used. However, paper has various advantages such as being abundant as a resource, being lightweight, inexpensive, easily crushed, and extremely easy to incinerate after use, as well as being able to be reused as waste paper. Therefore, there is a strong demand for containers for beer, carbonated drinks, etc. to switch to paper containers.

The main reason why the development of paper pressure containers has been delayed is firstly that the pressure resistance specifications required for pressure containers for carbon dioxide-containing liquids such as beer and carbonated drinks are quite high. By the way, beer weighs 2 to 5 kg/en at room temperature? G.

4-5 Kg/d G at 50℃ 1 Carbonated drinks are 3 at room temperature
It has an internal pressure of ~3.5 to 9/d G and 6 to 7 Kq/iG at 50°C. Secondly, since paper has poor bending properties, it is difficult to securely bond and secure the body and lid together by winding them together, as in the case of metal cans.

Despite these obstacles, the inventors of the present invention have focused on the many benefits that paper pressure-resistant containers have, and as a result of repeated research on steel quantity in an effort to realize them, have already obtained some knowledge. reached.

In other words, the container body has a multi-wall structure in which laminated paper laminated with a film having barrier properties is wrapped multiple times in a cylindrical shape, and the container lid has a multi-wall structure in order to have pressure resistance. In order to equalize the internal pressure, it is necessary to curve the shape into a spherical shell shape.1 As a lid body with such a shape, for example, thermoplastic material such as polyethylene, which is the raw material for paper, is used. We have discovered a lid body etc. obtained by heating and press-molding a non-woven fabric-like mat formed from a mixed pulp mixed with a synthetic pulp consisting of a resin.

On the other hand, the joint between the body and the lid must also satisfy this pressure resistance, but since paper has poor bending properties, this joint is sealed using the seaming method like a metal can. It is difficult to satisfy. Therefore,
A shape was considered in which the peripheral edge of the lid in contact with the body has a skirt part that is parallel to the body and fitted into the body for connection to the body.

That is, the shape of the pressure container includes, for example, the inner circumferential surfaces of the upper and lower ends of the tubular body 1 having a multi-wall structure manufactured in advance, and the outer circumferential surfaces of the skirt portions 2d provided on the lids 2 and 2', respectively. Was it firmly fixed with adhesive? A structure as shown in Figure A1 was considered. In this case, the joint between the body and the lid is bonded using thermoplastic resin, which is laminated to the outermost layer of the body and the lid, using adhesive.
It is firmly bonded and fixed using ultrasonic welding, high frequency induction heating welding, etc.

However, for containers such as beer and carbonated drinks, which have wide marketability and require high pressure resistance and perfect sealing, when considering the safety factor, the Such a joint structure cannot be used in a reasonable manner. For example, a body with an inner diameter of 751 m and a lid with an outer diameter of 75 cm are connected to the end of the body with a skirt part of an effective adhesive width of 10 mm, and this is OKg.
When an internal pressure of /lri G is applied, a load of 9 is applied to the inner surface of the lid body.

As a result, a force of 442 Kf acts as a shearing force on the joint, and if the effective bond width is 10, ls, s K9
/J of shear stress. The adhesive surfaces at the joint are strongly bonded and can withstand this level of shear stress, but even if the body paper itself is made of high-quality paper with long Norp fibers, the shear strength is still low. 1/clI in 15
Since there is only about P, a break occurs in the longitudinal direction along the paper layer adjacent to the joint.

Therefore, it is necessary to reinforce this joint by some means. This can be accomplished, for example, by folding the ends of the body inward, as seen in the bottom-lid joint of the paper cup in FIG.

-5= However, when this method is applied to a fuselage having a multi-wall structure according to the present invention, the thickness of the bending portion becomes thick due to the multi-wall structure, making it difficult to bend the fuselage easily. It's Kade.
Even if it is folded, the folded part will have significant wrinkles.
It cannot be said that it is desirable in terms of appearance.

In order to solve this problem, the present inventors conducted repeated research on the quantity of steel, and as a result, they completed the present invention.

The present invention provides an inner circumferential surface of a container body having a multi-wall structure in which at least the surface in contact with the contents is covered with a six-layer film and paper is wrapped at least twice, and A container having a structure in which the eye and the skirt part are adhesively fixed to the outer circumferential surface of the lid body, which is bent toward the inner circumferential edge of the body, and the skirt part is fitted to the body for joining with the body. The paper layer constituting the outermost layer of the body is bent inward of the body, and this folded portion covers the skirt portion of the lid and is firmly adhesively fixed. Yes The present invention will be explained in more detail below.

6- Fig. 3 is an enlarged view showing an example of the cross-sectional structure of the joint part of the container according to the present invention, showing a body 1 having two paper layers 1b and 1e, and a peripheral part of the body 1 having a joint with the body. Therefore, the lid body 2 includes a skirt portion 2d that fits into the body. The parts that are in contact with the contents of the body 1 and lid 2 are non-rear films 1a and 2a, respectively. Being lil'd. The paper layer 1e constituting the outer layer of the body 1 is bent inward at its ends and is adhesively fixed to the inner peripheral surface of the skirt portion 2d of the lid body 2 on the instep. Adhesion between the outer circumferential surface of the skirt and the inner circumferential surface of the body and the adhesion between the inner circumferential surface of the skirt and the bent portion of the body can be performed using thermal welding, ultrasonic welding, high-frequency induction heat welding, or adhesion as necessary. It is attached by adhesive or the like. In the joint structure according to the present invention, for example, an effective bonding width of 10 m between a body with an inner diameter of 75 mm and a lid body with an outer diameter of 75+W.
Glue the skirt part of m to the end of the fuselage and apply 10K to this.
g/cW? When an internal pressure of O is applied, the skirt part has a pressure of 18
．． A shear stress of 8Ky/7' is applied. If the shear strength of the paper of the body is 15 f/J, the remaining 3.8 Kr/- must be maintained by the joint structure according to the present invention in order to withstand this internal pressure. In the structure of the present invention, in addition to the above-mentioned shear strength L5Kg/crri', the joint part has
The tensile strength of the outermost layer of paper in the body with the folded ends acts. The breaking strength of the paper that makes up this outermost layer is 300Kq/
lri.

If the strain is 300 μ, the tensile strength acting on the joint is 9 Kq/lri, and the structure of the present invention has an internal pressure of 10
Kg/cn? It can sufficiently withstand G.

That is, the present invention can sufficiently withstand the specifications as a pressure-resistant container for beer and carbonated beverages, and since there is only one folded layer, wrinkles at the folded part can be reduced, and the appearance is improved. The present invention provides an extremely excellent paper pressure-resistant container that can be manufactured quickly and easily.

In FIG. 3, when the outermost layer 1e is bent, it is preferable that the gap 3 created between the end face of the inside body M1b and the end face of the skirt portion 2d is as small as possible;
In order to completely eliminate this gap, it is more preferable to bond the parts with an adhesive or the like to completely integrate the joined parts. That is,
If the joint part is integrated, the tensile strength of #1 and the paper at the folded part will affect the joint strength more effectively,
The effects of the present invention can be further expressed.

In addition, in the case of paper containers, in order to prevent the paper chicks from coming into direct contact with the contents or the outside air, the exposed parts of the paper such as the edges are covered with a thermoplastic resin film such as polyethylene film. Alternatively, a treatment such as wax coating may be applied. This end surface treatment is especially important for containers such as the beer and carbonated beverage containers of the present invention, which are subject to internal pressure and need to be prevented from permeating carbon dioxide gas. In the case of the container of the present invention, since the outermost layer of the body covers the exposed end portion of the inner layer of the body and the exposed end portion of the skirt portion of the lid body, the above-mentioned problem of edge treatment is also solved by the present invention. Is possible. In FIG. 3, the outer peripheral surface Fi of the outermost layer of paper 1e is usually covered with a thermoplastic resin film 1f such as polyethylene. For containers such as the container of the present invention that must prevent the permeation of carbon dioxide gas,
It is preferable that the covering film 1f of and 9- is also a non-rear film.

However, in general, anti-reflective films are expensive, and it is important to use them as little as possible.

Further, in containers of the present invention which have wide marketability, there is a risk that the covering film may be damaged depending on handling, and the repellency may be impaired in this area.

Therefore, the present inventors have developed a container with a higher level of 6-rear properties, so that even if the outer surface is damaged during handling, the 6-rear properties of the container will not be impaired, and the end face of the exposed end part will not be impaired. As a result of continued intensive research, we aimed to create a container that could be dried completely and the contents could be completely sealed.
We have now discovered a more preferable layer structure for the container body. That is, the container having the structure according to the present invention is characterized in that at least the inner peripheral surface of the paper constituting the outermost layer of the container body having a multi-wall structure is covered with a non-reacting film. . To explain in more detail in FIG. 3, the inner circumferential surface of the paper 1e constituting the outermost layer of the body 1 is covered with a layered film 1d. .

In the second invention of the present invention, regarding the covering film constituting the container body, there are no particular limitations on the covering film where the body contacts the contents and the covering film outside the inner circumferential surface v of the paper constituting the outermost layer, but for example, It is preferable that the film in contact with the non-reacting film 1d coated on the inner circumferential surface of the paper constituting the outermost layer, specifically the covering film 1c in FIG. 3, is also a non-reacting film. In other words, by bonding films with non-reacting properties, not only the non-reacting properties are further improved, but also the pinholes existing in the films are significantly reduced, and as a result, the pinhole defect rate of containers is reduced. can be significantly reduced.

In the present invention, a non-reactive film is defined as having a permeability of about 200 or less for oxygen, carbon dioxide, or other gases (the term "permeability" means 1 atm after reaching a stable state, 1 in 24 hours at a temperature of 23°C and a relative humidity of 50%.
mil thickness (meaning the number of cc of gas permeated per 1 m"). For example, polyvinylidene chloride sold under the trade name "Saran", polyamide, e.g. nylon, Polyester, biaxially oriented polyzolopyrene, polyvinyl chloride, vinylidene chloride-vinyl chloride copolymer, polyvinyl alcohol, ethylene sold under the trade name "Enol"
Saponified vinyl acetate copolymer resin, cellophane, polyacrylonitrile, and nitrile sold under the trade names of Rex 210J (manufactured by Vistron, USA) and "Rono ξ Tsuku" (manufactured by Monsando, USA) Films made of resins and the like are included.

These films may be a single layer or a laminate of two or more. It is also possible to use a film in which a non-thinning film is laminated on one or both sides of a non-thinning film. This type of laminate film includes, for example, a polyethylene/polyvinylidene chloride/polyethylene laminate film sold under the trade name "Saranex". In this case, polyethylene promotes thermal weldability and does not significantly affect gas permeability. However, it is also possible to use a film with a cellulose material applied to the surface of the film. Examples of this type of film include films coated with polyvinylidene chloride resin called ``Saran coated films'' or ``1 coated films,'' or films generally called 1 metalized films. is coated with aluminum vapor deposition. Furthermore, a film whose surface has been subjected to a moisture-proofing treatment, such as moisture-proof cellophane, can also be used.

Aluminum foil can also be used as a non-reacting film, but since it has poor thermal weldability, it is usually used by laminating it with a film such as polyethylene or ethylene vinyl acetate (EvA).

However, if the aluminum foil is not thicker than 30μ,
Since the gas barrier properties cannot be trusted due to pinholes, if the film is used at a thickness smaller than this, especially 10 μm or less, it is preferable to use it in a composite lamination with the above-mentioned plastic film. . In addition, any range can be used depending on the thickness of the film used in the present invention, the film's film properties, etc., but in order to be inexpensive and easy to handle, It is preferable that it be as thin as possible, and a thickness of 10 to 100 μm is generally preferable.

In the present invention, the container body has a multi-wall structure in which paper is wrapped at least twice, but the present invention does not particularly limit the type and thickness of the paper used therein. However, in the case of a container that requires pressure resistance as in the present invention, paper with excellent tensile strength and the like, such as softwood-based paper with relatively long pulp fibers, is preferred. Moreover, regarding the thickness, those having a thickness of 100 to 500 g/m2 are usually used.

The present invention provides a lid having a skirt portion fitted to the body in order to connect the lid with the body, and the skirt portion being bent in the direction of the inner circumferential edge of the body. There are no restrictions on the shape of the body.

For example, in FIG. 1, the spherical shell-shaped curved surface is convex toward the outside, but the present invention can be applied even if the curved surface is convex toward the inside. Further, from the original purpose of the present invention, a lid made of # is preferable, but the present invention is also applicable to a lid made of thermoplastic resin molded into the shape.

Examples of the present invention will be described below.
The present invention is not limited to these examples.

Example 1 A sheet of bleached kraft paper weighing 250 g/m2 with a thickness of 64 mm on one side.
Multi-layer non-resistance film made from μ polyethylene/polyvinylidene chloride/polyethylene (manufactured by Mukasei Kogyo ■,
The product name is ``Realon''), and one side is laminated with a 30μ thick polyethylene film.
A laminated paper was obtained from Nono Realon/Paper/Polyethylene.

Further, a polyethylene film having a thickness of 30 μm was laminated on both sides of the same paper to obtain a laminated paper consisting of polyethylene/paper/polyethylene.

Next, the laminated paper consisting of Nono Realon/Paper/No9 Realon was wrapped once around the mandrel so that the gills and edges overlapped each other by 1.5 degrees, and the weighted parts were bonded by heat welding. , forming an inner cylinder.

At this time, the above-mentioned Pallion film was subjected to chief-chip treatment so that the exposed portion of the paper did not come into contact with the contents at the edges. Next, polyethylene/paper/7I'! A laminated paper made of polyethylene is arranged so that its edges are offset by 180 degrees from the edges of the inner cylinder, and the edges are overlapped by 1.5 degrees each. A cylinder is formed, and the polyethylene films of the inner cylinder and outer cylinder that are in contact with each other are adhered to the entire surface by heat welding, and are integrated.
It formed a cylindrical body. The layer structure of this cylinder is: Nono Realon/Paper/Polyethylene/Polyethylene/Paper/
It is made of polyethylene and has an inner diameter of 75 m.

The height of the inner cylinder is 150m5+, and the height of the outer cylinder is 164hm.In order to bend the ends, one end of the outer cylinder is 150m5+ higher than the inner cylinder.
It was formed to be 2m+ long.

On the other hand, a non-woven mat made of a mixed pulp made by mixing softwood-based bleached kraft and e-lupe with a synthetic pulp made of polyethylene at a ratio of 25% by weight and t% is inserted into the mold,
The lid was heated and pressed at a mold temperature of 150°C and a press pressure of 30 to 9/- to form a lid with a spherical shell radius of 75 mm, a skirt portion 10 exposed, and an inner thickness of 1.5 m as shown in Fig. 1. Obtained. Next, the Nono Realon film was coated on both sides of the lid by heat welding.

Fit the lid obtained as above to the end of the body, bend the end of the outer cylinder to form a joint having the joint structure shown in FIG. 3, and then By ultrasonic welding, the outer circumferential surface of the skirt portion of the lid body, the inner circumferential surface of the body, and the inner circumferential surface of the skirt portion and the bent portion of the outer cylinder were firmly bonded and identified.

Next, a metal water injection lid was attached to the sacral opening of the body, and after it was sealed, pressurized water was supplied at room temperature and the pressure was measured when the joint between the body and the lid broke. . Measurement #-t5
The results are shown in the table.

Next, as Comparative Example 1, a container body and a lid were formed by the same method as in Example 1 except that the heights of the inner cylinder and the outer cylinder were made the same, and the joint part 17- structure shown in FIG. 1 was formed. After forming a joint having 100 mm, the body and lid were firmly adhesively fixed using the same ultrasonic welding method.

Next, a pressure test was conducted in the same manner as in the examples, and the results are shown in Table 1 along with the examples.

Table 1 The above results demonstrate that the present invention is extremely effective in terms of the strength of the joint between the body and the lid.

Example 2 35μ 1 on both sides of bleached kraft paper weighing 25017m
8- "Nono Rex 21o" film (manufactured by Vistron)
were laminated to obtain a laminated paper consisting of Parex/paper/Nonolex.

Next, using this f# layer paper, an inner tube and an outer tube were formed in the same manner as in Example 1 to form a cylindrical body. The layer structure of this cylinder is ・ζRex/Paper/・Norex/Norex/
It was made of paper/Nonolex, and its dimensions were the same as the cylinder of Example 1. In addition, the paper flaps at the edges of the inner cylinder and outer cylinder should be 3-3cm thick to prevent the paper from coming into direct contact with the waste inside or the outside air.
Edge treatment was performed with 5μ Barrettes film tape.

Next, a lid was formed from a non-woven mat in the same manner as in Example 1, and both sides of the lid were coated with a 35 μm Parex film using a urethane adhesive.

As in Example 1, this lid body is fitted to the end of the body, the outer cylinder end is bent to form the same joint structure as in Example 1, and then the body and lid body are bonded together by ultrasonic welding. was firmly glued and fixed.

Next, a metal water injection lid was attached to the other opening of the body, and after it was sealed, pressurized water was supplied at room temperature, and the pressure when the joint between the body and the lid broke was measured. Measurements were performed on five containers, and the results are shown in the table.

Next, as Comparative Example 2, a container body and a lid were formed by the same method as in Example 2 except that the heights of the inner cylinder and the outer cylinder were made the same, and had the joint structure shown in Fig. 1. After forming the joint, the body and lid were firmly adhesively fixed using the same ultrasonic welding method.

Next, a pressure test was conducted in the same manner as in Example 2, and the results are shown in Table 2 along with Example 2.

Table 2 Example 3 In the fuselage of Example 2, after forming the same fuselage as in Example 2 except that both ends of the outer cylinder were made longer by 12+o+ with respect to the inner cylinder, the same lids as in Example 2 were attached to both ends of this fuselage. The body was similarly firmly glued and fixed. A hole was pre-drilled in the center of one of the lids, and carbonated water was filled through this hole, and the hole was completely sealed with a metal tube to which a pressure gauge had been attached in advance. At this time, the pressure inside the container is 2.5Kq/crtP
It was G. Leave this container at room temperature for a month 1. However,
No decrease in internal pressure was observed.

As mentioned above, Examples 1, 2, and 3 shown above show that the present invention has a very large effect on the strength of the joint between the body and the lid. This shows that the container is fully capable of achieving its purpose as a container for beer and carbonated beverages, such as eliminating all gas leaks and perfecting the gas and gas resistance of the container. be.

21-

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the structure of an example of a paper pressure container;
The figure is a sectional view of a paper cup, and FIG. 3 is a partial sectional view of one example of the present invention. 1...Body 1a...Barrier film 1b...Paper layer (innermost layer) ld...Nono barrier film 1e...Paper layer (outermost layer) 1f...Outermost layer coating film 2.2t...Lid body 2a...NOS IJ carrier film 2d...Skirt portion Patent applicant Asahi Kasei Kohata Co., Ltd. 22- Fig. 1 Fig. 2 313

Claims (1)

[Claims] (1) The inner circumferential surface of a container body having a multi-walled structure in which at least the surface in contact with the contents is covered with a non-reacting film and paper is wrapped at least twice, and the peripheral edge is joined to the body. In a container having a structure in which the skirt part is fitted to the body for the purpose of the present invention, and the skirt part is adhesively fixed to the outer circumferential surface of the lid body which is bent toward the inner circumferential edge of the body, the outermost layer of the body is The edge of the paper layer that makes up the
A pressure-resistant paper container (2) characterized in that the body is bent inward, and the bent portion covers the skirt portion of the lid and is firmly adhesively fixed. The paper pressure-resistant container according to claim 1, wherein at least the inner circumferential surface of the paper constituting the outer layer is coated with a noseller film.