JPH0339903B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to composite cans and cans for filling and storing tea, coffee, cocoa, soft drinks, fruit drinks, alcoholic beverages, dairy products, and other drinking liquids. It relates to its manufacturing method.

[Prior Art] What is generally called a composite can is
As shown in the figure, the main body is paper, which is combined with plastic or metal to form a cylindrical body, to which upper and lower lids are attached.

This composite can usually uses a plastic film mainly made of olefin-based resin as the wetted material, and combines this with vapor-deposited aluminum or aluminum foil to make the innermost layer an inner film with improved gas barrier and waterproof properties. Special paperboard such as coated paper, which is made by coating paper with plastic, is heat-sealed or coated with adhesive to form multiple layers in a cylindrical shape, and printed paper called a label is attached to the outermost layer, or as a substitute for a label. It was formed by thermal transfer printing, etc.

[Problems to be solved by the invention] Conventional composite cans contain off-flavors,
There were problems with off-taste and color change. In other words, since an olefin-based combination film is mainly used for the innermost layer, a large amount of the aroma components of the contents are adsorbed, and due to heat resistance issues, the filling temperature is also lower than that of metal cans, so there is less residual content after the container is sealed. The amount of oxygen is large, and due to the two causes of adsorption and oxidation, taste,
Deterioration of aroma and change in color were more common than with other food containers.

In addition, because conventional composite cans are containers made of a combination of aluminum vapor-deposited film, gas barrier resin film, and paper, they resist the vacuum state that occurs when hot sake is filled and then cooled, that is, the negative pressure that occurs from the outside inward. Another problem was that the contents deteriorated due to oxidation brought about by the infiltration of outside air and the decrease in the degree of vacuum and decompression resistance, and in particular, there was a problem that vitamin C decreased over time.

For this reason, there has been a strong desire for technical improvements to prevent the quality of the contents from deteriorating.

Next, the following problems were pointed out regarding performance.

First, there was a problem in that it had internal pressure resistance, that is, it had good air permeability from the inside to the outside, and its blow-up strength was weak compared to other containers.

In addition, the paper forming the can body swells and softens due to the influence of the contents and moisture from the outside due to poor adhesion of the inner film and the outer label, weakening the strength of the can body (paneling strength). There was a problem with low water resistance and waterproofness.

Furthermore, as a problem of surface friction resistance, the surface gloss and surface slipperiness seen in metal cans are poor. Since this is not done on cans, surface slippage,
It is inferior in terms of hardening, and has the problem of being significantly inferior to metal cans in terms of suitability for vending machines and high-speed filling and conveyance lines.

Furthermore, it was pointed out that a problem with the manufacturing method was that the cylinder manufacturing speed was low.

For example, paper tubes that do not use an inner film (such as the core of household aluminum foil) are made at a speed of 50 tube meters or more per minute. Due to the problem of slippage on the core of the cylinder (the rod for wrapping it), the speed at which cylinders are made is limited, and at the same time, it is necessary to use a highly slippery film, that is, an olefin-based film, which has traditionally been the most suitable raw material. In such a case, the problem of the above-mentioned quality image, which is the problem of taste, aroma, and color tone, will be deteriorated, there will be no decisive decision on the selection of the inner film, and the cylinder manufacturing speed will be limited to about 50% of that of paper cylinders. It's summery.

Next, there was the problem of a high loss rate. Normally, the outside label is attached at the same time as the cylinder, so troubles during cylinder manufacturing, dimensional defects during cutting, and misalignment of labels and printing are concentrated in this area, resulting in a very high defect rate. While the loss rate for metal cans was less than 1%, the loss rate for composite cans exceeded 5%.

Furthermore, there was a problem in that the cylinder making and can making equipment were expensive.
This is because a spiral winder that uses an inner film requires extremely advanced techniques such as film sliding and heat welding, so it requires extremely expensive equipment such as Teflon coating on the mandrel and hot air control for heat welding. This was a major deviation from the perspective of manufacturing and supplying products at the lowest cost possible.

[Summary of the Invention] The present invention has been made to solve the problems of the above-mentioned conventional technology. At the same time, it has excellent heat resistance, the paper cylinder does not swell or soften due to the influence of moisture from the contents or the outside, and has excellent water resistance and water resistance. To provide a composite can and its manufacturing method that prevents outside air from penetrating over time, improves the degree of vacuum and depressurization resistance, prevents deterioration of the contents, especially vitamin C, and prevents deterioration of the quality of the contents. The purpose is to provide.

In addition, the present invention has internal pressure resistance, that is, there is no air permeability from the inside to the outside, and the blow-up strength is strong, and the paper forming the can body swells and softens due to the influence of contents and moisture from the outside. To provide a composite can which maintains can body strength (paneling strength), is excellent in water resistance and waterproofness, and has excellent surface friction resistance, and a method for manufacturing the same.

Furthermore, it is an object of the present invention to provide a composite can that can be manufactured and supplied at the lowest possible cost, with high cylinder manufacturing speed, low loss rate, and inexpensive can manufacturing equipment, and a method for manufacturing the same. purpose.

[Means for Solving the Problems] The present invention employs the following means to solve the above problems.

First of all, the first invention is a cylindrical stack of paper tube base paper 1 made of special paperboard made of kraft paper using virgin pulp or kraft paper made with additives added to have the same performance. Then, a metal foil 2 such as aluminum foil, iron foil, or stainless steel foil is adhesively laminated on the outside of this paper tube base paper 1, and a paper tube base paper 3 made of the above-mentioned special paperboard is adhesively laminated on the outside of this metal foil 2. A paper tube base paper 4 made of the above-mentioned special paperboard is further adhesively laminated on the paper tube base paper 3, a thin paper 5 is adhesively laminated on the paper tube base paper 4, and a plurality of layers are laminated in a cylindrical shape to form the inner surface of the can body 6. After directly spraying or coating the inner surface coating 7 made by dissolving a thermosetting resin such as vinyl chloride in a solvent such as methyl ethyl ketone, the innermost layer 8 is formed by heat curing treatment, and the surface coating is applied to the outer thin paper 5 of the can body 6. This composite can is printed and has a surface waterproof coating, and is characterized by having metal lids 9 and 10 on the top and bottom of the can body 6.

Next, the second invention is kraft paper using virgin pulp for the mandrel of the spiral winder.
Alternatively, paper tube base paper made of special paperboard made of kraft paper or the like with additives added to have equivalent performance is laminated in a cylindrical shape, and the outside of this paper tube base paper is coated with aluminum foil, iron foil, etc. Metal foil such as stainless steel foil is adhered and laminated with a heat-resistant adhesive, and a paper tube base paper made of the above-mentioned special paperboard is adhered and laminated on the outside of this metal foil with a heat-resistant adhesive. A paper tube base paper consisting of the above is further adhesively laminated with a heat-resistant adhesive, thin paper is adhesively laminated on this paper tube base paper with a heat-resistant adhesive, and the can body made into a cylinder is cut into a predetermined size with a cutter, The inner surface of the can body formed by laminating multiple layers into a cylindrical shape was sprayed or coated with an inner surface paint made by dissolving a thermosetting resin such as vinyl chloride in a solvent such as methyl ethyl ketone using a spray machine to provide an inner waterproof coating. After that, the coating agent is dried in a drying oven and at the same time heat-cured to form the innermost layer, and after surface printing and surface coating on the outer thin paper of the can body using a curved printing machine, it is placed in a drying oven or an ultraviolet oven. A method for producing a composite can, characterized in that the composite can is dried and surface hardened, the mouth of the can body is widened to form a flange using a flange, and metal lids are provided above and below the mouth of the can body using a seamer. be.

[Effect]

By having the above-mentioned structure, the present invention uses a thermosetting resin as a wetted material and the entire can has excellent heat resistance, so that it can prevent the contents from deteriorating, adsorbing aromatic components, and oxidizing. The can body does not swell or soften due to the influence of contents or moisture from the outside, and the can body does not swell or soften due to the influence of contents or moisture from the outside. Against the negative pressure generated inward from
There is no penetration of outside air over time, and the degree of vacuum and depressurization resistance are improved, so there is no deterioration of the contents, especially vitamin C, which does not decrease over time, and it is possible to prevent the quality of the contents from deteriorating.

In addition, the present invention has internal pressure resistance, that is, there is no air permeability from the inside to the outside, and the blow-up strength is strong, and the paper forming the can body swells and softens due to the influence of contents and moisture from the outside. It maintains can body strength (paneling strength) and is water resistant.
It has excellent waterproofness and surface friction resistance.

Furthermore, the present invention has a high cylinder manufacturing speed, a low loss rate, and inexpensive cylinder and can manufacturing equipment, and can be manufactured and supplied at the lowest possible cost.

[Example] First, the first invention will be explained based on FIG. 2. The material is kraft paper using virgin pulp, or kraft paper made by adding additives to have the same performance. Paper tube base paper 1 made of special paperboard is laminated in a cylindrical shape, and this paper tube base paper 1
A metal foil 2 such as aluminum foil, iron foil, or stainless steel foil is laminated on the outside with a heat-resistant adhesive.
On the outside of this metal foil 2, a paper tube base paper 3 made of the above-mentioned special paperboard is adhered and laminated with a heat-resistant adhesive, and on this paper tube base paper 3, a paper tube base paper 4 made of the above-mentioned special paperboard is bonded and laminated with heat-resistant adhesive. A thin paper 5 is further adhesively laminated to the paper tube base paper 4 using a heat-resistant adhesive.

The inner surface of the can body 6, which is formed by laminating multiple layers in a cylindrical shape, is directly sprayed or coated with an inner surface paint 7 made by dissolving a thermosetting resin such as vinyl chloride in a solvent such as methyl ethyl ketone, and then subjected to thermosetting treatment. The outer thin paper 5 of the can body 6 is coated with surface printing 22 and a surface waterproof coating 20, and the top and bottom of the can body 6 are covered with metal lids 9. , 10 are provided and the composite can 2
3 is formed.

Next, the second invention will be explained based on FIG. 3. The mandrel 11 of the spiral winder is made of kraft paper using virgin pulp, or kraft paper made by adding additives to have the same performance. Paper tube base paper 1 made of special paperboard is wound into a cylindrical shape at a predetermined angle and laminated.
A metal foil 2 such as aluminum foil, iron foil, or stainless steel foil is wrapped around the outside of this paper tube base paper 1 in a cylindrical shape at a predetermined angle with a heat-resistant adhesive and laminated with adhesive.
A paper tube base paper 3 made of the above-mentioned special paperboard is wrapped around the outer side of the paper tube base paper 3 in a cylindrical shape at a predetermined angle using a heat-resistant adhesive and adhesively laminated, and a paper tube base paper 4 made of the above-mentioned special paperboard is attached to this paper tube base paper 3 with a heat-resistant adhesive. The paper tube base paper 4 is further wrapped in a cylindrical shape at a predetermined angle with an adhesive and adhesive laminated, and the thin paper 5 is wrapped around the paper tube base paper 4 with a heat-resistant adhesive in a cylindrical shape at a predetermined angle and adhesive laminated. The can body 6 is cut to a predetermined size using a cutter 12, and an inner surface paint 7 made of a thermosetting resin such as vinyl chloride dissolved in a solvent such as methyl ethyl ketone is sprayed onto the inner surface of the can body 6 formed by laminating the can body 6 into a cylindrical shape. After applying a waterproof coating on the inner surface by direct spraying or coating with a machine 13, the coating agent is dried in a drying oven 14 and at the same time subjected to heat curing treatment to form an innermost layer 8, which coats the outer surface of the can body 6. Curved surface printing machine 15 on thin paper 5
After surface printing 22 and surface coating, drying and surface hardening are performed in a drying oven or ultraviolet oven 16, the opening is widened to form a flange using a flangeer 17, and metal caps are attached to the upper and lower openings using a seamer 18. 9 and 10 are provided.

After completely applying the inner surface paint 7 to the upper and lower cuts of the can body 6, which are the inner surface of the can and the end surfaces of the can, using a spray machine 13 or the like, heat treatment is performed in a drying oven 14 at a temperature of about 180° C. for about 10 minutes. The innermost layer 8 is formed by scattering a solvent such as methyl ethyl ketone and the solvent of the heat-resistant adhesive at high temperature, and at the same time hardening the thermosetting resin such as vinyl chloride in the inner surface coating 7.

In this heat treatment process, if it is carried out at a temperature of 200°C or higher, carbonization of the paper tube base paper will progress gradually, but as in the example of the present invention, if it is carried out at a temperature of around 180°C,
Carbonization does not occur with heat treatment for about 10 minutes. However, the moisture content of the paper tube base paper is only slightly reduced, and there is no change in its performance as a can body.

By adopting this process, adsorption of aroma components, which is seen when using conventional olefin combination films, is greatly reduced, resulting in off-flavors and
Off-taste is prevented.

At the same time, the container is dried at a high temperature of around 180°C and its inner surface is thermoset, making it heat resistant and able to withstand high filling temperatures, reducing the amount of residual oxygen and preventing deterioration of the contents due to oxidation. At the same time, the color tone of the contents deteriorates due to oxidation and adsorption, and vitamin C
decrease over time is prevented.

After surface printing and surface coating are performed on the outer thin paper 5 of the can body 6 using a curved surface printing machine 15, the composite can is dried and surface hardened using a drying oven or an ultraviolet oven 16. The surface gloss is comparable to that of metal cans, and the surface hardening and surface slipperiness are also good, making it comparable to metal cans in terms of suitability for vending machines and high-speed filling and conveyance lines.

This drying and surface hardening process in the drying oven or ultraviolet oven 16 is performed in the drying oven 16.
When an ultraviolet oven 16 is used, a solvent is scattered, and when an ultraviolet oven 16 is used, a photosensitive polymerization initiator is reacted to ensure surface gloss, surface hardening, and surface slipperiness. Note that energy costs are relatively high in the case of a drying oven, but energy costs are low in the case of an ultraviolet oven.

The composite can of the present invention does not have all functions such as waterproofness, content resistance, and gas barrier properties on the inner surface film as in the conventional method, but instead uses the innermost layer 8 made of thermosetting resin paint as described above. The metal foil 2 is sandwiched between the paper tube base paper 1 and 3 laminated in multiple layers, or the paper tube base paper 1 is made to have waterproofness and content resistance.
Alternatively, a method is adopted in which the tubes are made by laminating the tubes in step 3 and gluing them together with adhesive.

Since the metal foil 2 is laminated with a thickness (approximately 30 microns) without any pinholes, it has excellent resistance to internal pressure and negative pressure, and prevents penetration of outside air and penetration of internal pressure to the outside. This prevents the contents from deteriorating due to oxidation.

Internal pressure resistance is improved by using metal foil instead of conventional aluminum vapor-deposited film, and blow-up strength can be strengthened.

When the inner surface coating is performed, the inner surface coating 7 forms the innermost layer 8 and at the same time partially impregnates the paper tube base paper 1, and the surface coating becomes integrated with the paper tube base paper 1. By curing this by heat treatment, the final coat is formed. inner layer 8,
The paper tube base paper 1 and the inner layer surface coating are strengthened, and a decrease in strength due to swelling of the can body due to moisture due to poor adhesion of the inner surface film, which is observed in conventional composite cans, is prevented.

In addition, in order to prevent moisture from entering from outside the can, after printing, surface coating paint is applied and then hardened and waterproofed through heat treatment or ultraviolet rays, which strengthens the can body and makes it waterproof and water resistant. It can be strengthened.

In contrast to conventional composite cans with label wrapping or surface transfer printing, the composite can of the present invention adopts an offset printing method after cylinder making and cutting.
The joints of the paper tube base paper 4 are covered, and the thin paper 5 is coated with a white base coat, offset printing, and surface coated, and then cured by heat treatment or ultraviolet treatment, resulting in a higher gloss than conventional composite cans. , has much better performance in terms of surface strength and frictional resistance.

Because the equipment and manufacturing method is exactly the same as that used for conventional paper tubes (household aluminum foil, wrap cores, etc.), there is no need to consider film slippage or heat generation (when it slides). It is possible to make tubes at an extremely high speed, which is approximately three times as fast as the current core tube making machine.

In the method of the present invention, since outer label adhesion is not performed, troubles associated with outer label adhesion unlike conventional composite cans are not concentrated on the cylinder making machine, and the machine operating rate and loss rate are reduced.

In addition, in FIG. 3, 19 is a paper cylinder drive belt,
20 is an overcoat, and 21 is an adhesive application roller.

[Effect of the invention] Therefore, according to the method of the present invention, the deterioration of the contents,
Adsorption of aroma components, low oxidation, off-flavor,
There is no off-taste or color change, and at the same time, it has excellent heat resistance, and the paper body does not swell or soften due to the influence of moisture from the contents or outside, and has excellent water resistance and water resistance. Due to the negative pressure that occurs over time, there is no infiltration of outside air over time, and due to improved vacuum degree and decompression resistance, there is no deterioration of the contents, especially vitamin C deterioration over time, and the quality of the contents is prevented from deteriorating. It is something that can be done.

In addition, the present invention has internal pressure resistance, that is, there is no air permeability from the inside to the outside, and the blow-up strength is strong, and the paper forming the can body swells and softens due to the influence of contents and moisture from the outside. It maintains the strength of the can body (paneling strength), has excellent water resistance, and has excellent surface friction resistance.

Furthermore, the present invention has a high cylinder manufacturing speed, a low loss rate, and inexpensive cylinder manufacturing and can manufacturing equipment, so that it can be manufactured and supplied at the lowest possible cost.

[Brief explanation of the drawing]

The drawings show one example of the implementation of the present invention, and FIG. 1 is a sectional view showing a conventional composite can, and FIG.
The figure is a cross-sectional view showing the composite can of the present invention.
The figure is a partially cutaway enlarged sectional view of the same as above, and FIG. 4 is an explanatory diagram showing the steps of the method of the present invention. 1, 3, 4...Paper tube base paper, 2...Metal foil, 5...
...Thin paper, 6...Can body, 7...Inner surface paint, 8...Innermost layer, 8, 9, 10...Metal lid.

Claims (1)

[Scope of Claims] 1 Paper tube base paper 1 made of special paperboard made of kraft paper using virgin pulp or kraft paper made with additives added to have equivalent performance, etc., is shaped into a cylinder. A metal foil 2 such as aluminum foil, iron foil, or stainless steel foil is adhesively laminated on the outside of this paper tube base paper 1, and a paper tube base paper 3 made of the special paperboard is adhesively laminated on the outside of this metal foil 2. A paper tube base paper 4 made of the special paperboard is further adhesively laminated on this paper tube base paper 3, a thin paper 5 is adhesively laminated on this paper tube base paper 4, and a plurality of layers are adhesively laminated in the cylindrical shape to form a can body 6. After spraying or applying an inner surface coating 7 made of a thermosetting resin such as vinyl chloride dissolved in a solvent such as methyl ethyl ketone to the inner surface, a thermosetting treatment is performed to form an innermost layer 8, and the inner layer 8 is coated on the outer thin paper 5 of the can body 6. A composite can, which has been subjected to surface printing and surface waterproof coating, and is characterized in that metal lids 9 and 10 are provided on the top and bottom of the can body 6. 2. For the mandrel of the spiral winder, paper tube base paper made of special paperboard made of kraft paper using virgin pulp or kraft paper made with additives added to have equivalent performance is laminated in a cylindrical shape. A metal foil such as aluminum foil, iron foil, or stainless steel foil is adhered and laminated on the outside of this paper tube base paper using a heat-resistant adhesive, and a paper tube base paper made of the special paperboard is laminated on the outside of this metal foil using a heat-resistant adhesive. A paper tube base paper made of the special paperboard is further adhesively laminated on this paper tube base paper using a heat-resistant adhesive. Thin paper is adhesively laminated on this paper tube base paper using a heat-resistant adhesive. The cylindrical can body is cut to a specified size with a cutter, and the inner surface of the can body is laminated into a cylindrical shape. An inner surface paint made by dissolving a thermosetting resin such as vinyl chloride in a solvent such as methyl ethyl ketone is applied to the inner surface of the can body using a spray machine. After applying a waterproof coating on the inner surface by spraying or coating, the coating agent is dried in a drying oven and at the same time heat-cured to form the innermost layer. After printing and surface coating, dry and surface harden in a drying oven or ultraviolet oven, and expand the mouth of the can body with a flange to form a flange.
A method for manufacturing a composite can, characterized in that metal lids are provided at the upper and lower mouths of the can body using a seamer.