JPH02255333A - Deoxidation functional laminated body excellent in adhesive property and production thereof - Google Patents

Abstract

PURPOSE:To obtain a deoxidation functional laminated body which has an unbonded part as a deoxidation functional layer and is excellent in adhesive property by separating an adhesive layer being the intermediate layer of organic resin and a metallic body two-dimensionally and geometrically into a deoxidation functional part and a bonding functional part and further strengthening the functions of the respective parts. CONSTITUTION:In the distribution of a bonding functional part, when this bonding functional part is distributed in an islandlike shape, bonding force is made comparatively weak. The area of the bonding functional part must be made wide in order to prevent it and thereby the area of a deoxidation functional part is narrowed and deoxidation capacity is lowered. Therefore bonding force can be enhanced even in the same area by distributing the deoxydation functional part in the islandlike shape. In other words, the adjacent unbonded parts are preferably made an isolated shape as shown in a figure. Further the area of the unbonded part is desirably made small and regulated to <=2cm<2> preferably <=0.5cm<2> because a film is easy to be damaged by handling such as covering, double-seaming, piling-up and transport when the area of the unbonded part is made large.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a material that has excellent adhesion and is used as a material for sealed containers such as beverage cans and food cans that store contents that are easily deteriorated and changed in quality by oxygen. The present invention also relates to a laminate having an oxygen scavenging function.

[Prior Art] Conventionally, canned goods used for long-term preservation of beverages and foods have been generally heat sterilized, filled with nitrogen, etc. to prevent oxygen contamination as much as possible. In addition, in order to prevent the contents of cans or bottles from deteriorating due to oxygen, reducing organic compounds such as sulfoxylates and dithionites are wrapped and enclosed in breathable film, etc., and oxygen is removed from these reducing organic compounds. It was common to avoid deterioration of the contents by allowing the compounds to oxidize.

Recently, as seen in Japanese Unexamined Patent Publication No. 61-295396, a material for cans having oxygen scavenging ability has been invented and is attracting attention as a cheaper and more effective method of manufacturing the material for making oxygen scavenging mills. In other words, in order to create this oxygen scavenging functional layer, a hydrophilic coating layer is applied on the metal body, and a resin coating with excellent oxygen and water permeability, mainly polymethylpentene or polybutadiene, is adhered with an adhesive. Manufactured.

[Problems to be solved by the invention] However, since the adhesives used for polymethylpentene and polybutadiene, which have excellent oxygen permeability, have low oxygen and water permeability, it is necessary to make the adhesive layer as thin as possible or Improvements have been made by adding auxiliary agents such as water-soluble polymers.

However, not only did it require advanced skills and techniques to thinly apply the adhesive, but the adhesion to the oxygen/water permeable film was not sufficient, and it was necessary to add a water-soluble polymer to the adhesive. As a result, the adhesion deteriorated. Therefore, it is necessary to form an adhesive layer without exhibiting the adhesive's original adhesive strength, and the processes or inter-processes until the contents are returned to the can body - shearing of the laminate, threading, piling, and lid making. It was necessary to be extremely careful in handling the parts, such as seaming and tightening, and a great deal of ingenuity was also required.

[Means for Solving the Problems] Therefore, as a result of various studies to solve this problem, the present inventors have developed a two-dimensional and geometric method to remove the adhesive layer, which is an intermediate layer between the organic resin and the metal body. We have discovered that by separating the oxygen function part and the adhesive function part and strengthening the functions of each part, it is possible to effectively exert both functions.

In other words, when adhering the organic resin coating to the metal body, in which a hydrophilic coating layer is applied to the surface, and an organic resin coating that has excellent oxygen and water permeability and is impermeable to metal ions is applied on top of the hydrophilic coating layer, We have invented an oxygen scavenging functional laminate with excellent adhesion, which is characterized by partially forming an adhesive layer and using the non-adhesive part as an oxygen scavenging functional layer.

[Function] In the present invention, a hydrophilic coating layer is applied on a metal body,
An adhesive layer is partially formed thereon, and an oxygen/water permeable film such as polymethylpentene or polybutene is applied thereon.

Of course, the adhesive layer may be formed on the non-applied portion of the partially applied hydrophilic coating layer so as to be applied directly to the metal body.
However, the hydrophilic coating layer is very thin, and applying an adhesive layer on top of it is no different from applying the adhesive directly.

Regarding the distribution of adhesive functional parts, if the adhesive functional parts are distributed like islands, the adhesive force will be relatively weak, and to prevent this, the area of the adhesive functional parts must be widened, and the oxygen scavenging function This results in a smaller area and lower oxygen scavenging ability. Therefore, it is possible to increase the adhesive strength even if the area is the same by distributing the oxygen scavenging functional parts in an island shape.

That is, as illustrated in FIG. 1, a shape in which adjacent non-bonded parts are isolated is preferable.

Furthermore, an adhesive with a normal T-beer strength of 500 g/cm (pulling speed 20 (1 mm/+in), film thickness 50
When the area ratio of the non-adhesive part/adhesive part is smaller than 0.1, the oxygen scavenging ability is 1 ps compared to the laminate with no functional separation.
If it becomes 15 or less, it cannot be put to practical use, and if it becomes 9.0 or more, the adhesive strength decreases significantly and peeling occurs even in the 7■ extrusion Erichsen test. Further detailed investigation revealed that the oxygen scavenging ability is more than half that of steel plates without functional separation, the adhesive strength is 7ma + no peeling in the extrusion Erichsen test, and the T-beer strength is more than 500g/cm. It was found that if the area ratio of the non-bonded part/bonded part was set in the range of 0.5 to 3.0, both the oxygen scavenging ability and the adhesive strength could be satisfied.

Regarding the area of the non-adhesive part, if it becomes large, the film is likely to be damaged by handling such as lid making, seaming, piling, transportation, etc., so it is preferable that the area is small.
It has been found that the thickness is preferably 0.5 cm2 or less, preferably 0.5 cm2 or less.

Regarding the shape and arrangement of the non-bonded part, polygons such as triangles and squares, ellipses, circles, etc. can be considered, but if the adhesive force has some directionality or if the area ratio of the non-bonded part to the bonded part is limited. I had to be careful because there might be stags. It was also effective to intentionally select the type of shape when there was a directionality to the machining. In short, it is sufficient as long as the deoxidizing function can be sufficiently performed even after the lid is manufactured.

As for the thickness of the adhesive, it is not necessary to consider oxygen scavenging ability as in the past, so it can be made sufficiently thick. As a result of investigation, the optimum range was 2 to 200 μm. If the thickness was less than 2 μm, the adhesive strength would be too low, and even if the coating was applied in an amount exceeding 200 μm, the adhesive strength would not change.

The commonly used adhesive method is to gravure print an adhesive containing a low-temperature curing or thermoplastic resin so that it is partially applied to an oxygen/water permeable film, and then dry it by heating etc. until it becomes tack-free. This can be thermocompression bonded to a steel plate provided with a hydrophilic outer coating, or it can also be thermocompression bonded to a film immediately after gravure printing.

It is also possible to make a hole in the portion of the adhesive film that will become the oxygen scavenging function, and then thermocompression bond it to the oxygen/water permeable film, and then thermocompression bond it to a metal body provided with a hydrophilic coating layer.

The reason why this method of applying the adhesive layer to an oxygen/water permeable film was adopted is that it is easier to handle than the method of applying an adhesive layer to a metal body.

In this case, the drying temperature of the adhesive must be below the softening point of the oxygen/water permeable film, but sufficient time can be provided. In some cases, it is also possible to partially employ ultraviolet curing or electron beam curing.

The adhesive may be selected from those that have excellent adhesion between the oxygen/water permeable film and the metal body or hydrophilic coating layer. For example, adhesive films may include modified olefin, polyacrylate, polyester, and polyurethane adhesives. Polyisocyanate-based, phenol-based, epoxy-based, amine-based, polyisocyanate-based adhesives are used alone or in combination with thermoplastic adhesive resins, etc., and the above-mentioned ultraviolet curing or It is also possible to incorporate an electron beam curing resin.

[Example] The present invention will be specifically described below based on examples.

Example-1 First, a hydrophilic coating composition consisting of a 3% aqueous solution of hydroxyethyl cellulose was coated on a 0.24 mm thick cold-rolled steel plate as a base metal plate using a reverse coater so that the dry film thickness was 0.25 μm. Then, dry it in a hot air oven at 190℃ for 40 seconds, and leave it as it is.
The two polymethylpentene films were laminated using a roll laminator and immediately cooled with water to obtain a steel plate with oxygen scavenging ability.

As shown in Figure 1, a polyurethane adhesive was applied to the corona surface of the film in advance to a dry thickness of 10 mm in areas other than the circular part of 0.5 ma + φ so that the non-adhesive area/adhesive area = 1.0.
The material was gravure printed with μI and dried at 80° C. for 5 seconds.

The resulting oxygen-absorbing steel sheet was evaluated for film beer strength, process adhesion, and oxygen-absorbing ability using the methods described below.

■ Beer strength: 10+*mfi x 1 from sample
Cut out a 20+u+ sample and peel off a portion of the film at one end. The peeled film and the peeled steel plate were placed between the chucks of a tensile tester and tested at a speed of 200a+m/a+in.
The tensile and peel strengths were determined.

■Processing adhesion test: A #-shaped cross cut with a width of 5 mm as shown in JIS -6744 is placed on the film surface, and
An Erichsen test of mm was conducted to observe the presence or absence of peeling of the film after processing.

(2) Oxygen scavenging ability evaluation test: A resin-coated steel plate was used as the lid of a cylindrical glass container with a diameter of 85 mm and an internal volume of 350 m1, beer was poured into the container and the container was sealed to have a head space of about 24 ffil. After 30 hours at 20℃,
Oxygen concentration was measured using a gas chromatograph.

Example-2 0.5 l on a modified polyethylene film with a thickness of 30 μm
A hole of 1taφ was made and the non-adhesive part/adhesive part was arranged so that the ratio was 1.0, and this was thermocompression bonded to the above polymethylpentene film at a temperature of 150°C, and this film was placed on a cold rolled steel plate in the same manner as above. It was roll laminated onto a 0.25 μm thick hydroxyethyl cellulose layer. Using this sample as a sample, the beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Example 3 A hole of 0.5 mmφ was made in a modified EV^ film with a thickness of 30 pm, and the hole was arranged so that the non-adhesive part/adhesive part -1,0 was bonded to the above polymethylpentene film at a temperature of 160°C. This film was roll laminated onto a 0.25 km thick hydroxyethyl cellulose layer on a cold rolled steel plate in the same manner as above. Using this sample as a sample, the beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Example 4 A hole of 0.5 mmφ was made in a modified PP film with a thickness of 30 μm, and the film was arranged so that the non-adhesive part/adhesive part was -1,0, and the film was thermocompression bonded to the above polymethylpentene film at a temperature of 170°C. This film was roll laminated onto a 0.25 μm thick hydroxyethyl cellulose layer on a cold rolled steel plate in the same manner as above. Using this sample as a sample, the beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Example-5 A modified PP film with a thickness of 30 pm was slit, and a thickness of 0.1
A cloth made of amφ threads with a porosity of 1.0 was woven and thermocompression bonded to the above polymethylpentene film at a temperature of 170°C. Roll laminated onto a 25 μm thick hydroxyethyl cellulose layer. Using this sample as a sample, the beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Comparative Example-1 A hydrophilic coating composition consisting of a 3% aqueous solution of hydroxycellulose was first applied to a cold-rolled steel plate with a thickness of 0.2411101 using a reverse coater so that the dry plate thickness was 0.2 μl. , 200 t: for 30 seconds to obtain a steel plate having a hydrophilic coating layer. Next, apply 2 μl of polyurethane adhesive as a dry film on top.
It was also painted using a reverse roller coater so that it would look like this. Then dry and heat in a gas oven for 3
After heating the steel plate to 200°C in 0 seconds, while maintaining the same temperature, a polymethylpentene film with a thickness of 50Pm was immediately laminated using a roll laminator, and immediately cooled to remove oxygen from the resin. liquid? I got an Im board. As a sample of what was obtained,
The beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Comparative Example-2 Polyurethane adhesive was applied in advance to the corona-treated surface of the polymethylpentene film outside the 0.5 amφ circular part as shown in Figure 2, and dried so that the non-adhesive area/adhesive area = O, OS. The material was gravure printed to a thickness of IQILm and dried at 80° C. for 5 seconds, and was roll laminated onto a 0.25 μm thick hydroxyethyl cellulose layer on a steel plate in the same manner as above. Using this sample as a sample, the beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

Comparative Example 3 Polyurethane adhesive was applied to the corona-treated surface of the polymethylpentene film in advance to a dry thickness of 10 μm so that the non-adhesive area/adhesive area = 10.0 in areas other than the square area of 10 mm on each side, as shown in Figure 2. Gravure mark 11, 80℃
The sample was dried for 5 seconds and then roll laminated onto a 0.25 μm thick hydroxyethyl cellulose layer on a steel plate in the same manner as above. Take this as a sample,
The beer strength, process adhesion, and oxygen scavenging ability of the film were evaluated.

The evaluation results of each of these example laminates and comparative laminates are
Shown in the table.

In Example-1, the adhesive layer was formed partially and thickened to 10 microns, and compared to Comparative Example-1, which had a thin adhesive layer of 2 microns and was formed over the entire surface, the oxygen scavenging ability was almost non-existent. Even though it doesn't change, the adhesive strength is 550 in beer strength.
It can be seen that g/cm has improved to 690 g/cm. Comparative Examples 2 and 3 are cases where the area ratio of the non-bonded part/bonded part was changed to 0.05 and 10, respectively, compared to 1.0 in Example-1. If it is too small compared to Comparative Example 2, the oxygen scavenging ability will be small, and therefore the oxygen content in the oxygen scavenging ability evaluation test will show a high value, and if it is too large, the adhesive strength will be low as in Comparative Example 3. is weak, and the beer strength is 350 g/cm, making it unusable.

Examples 2, 3, and 4 are cases in which various thermoplastic olefin films different from the thermosetting adhesive in Example 1 are used as adhesives, and in Example 5, the form of the adhesive is cloth-like. This is what I did. These results show that the deoxidizing functional laminate of the present invention has excellent adhesion without deteriorating its deoxidizing ability, regardless of the type or form of the adhesive.

Furthermore, in Comparative Example 1, an adhesive was applied to a metal body having a hydrophilic coating, and the adhesive was laminated after heat activation, whereas in Examples 1 to 5, an adhesive was applied to an oxygen/water permeable coating. After applying the adhesive, it was thermocompressed onto a metal object. Comparative Example 1 had a narrow range of suitable conditions due to the constraints of applying the adhesive uniformly, heating, laminating, and other processes involving the metal object, resulting in poor adhesion and variations in adhesiveness. However, if an adhesive is applied to the oxygen/water permeable film, workability and transportability will be improved, the adhesive application conditions will be easily satisfied, and the adhesion will be more stable. was possible.

[Effects of the Invention] The present invention two-dimensionally and geometrically separates the surface of the metal body and the intermediate layer of the oxygen/water permeable film into an oxygen scavenging function part (non-adhesive layer) and an adhesive layer, and improves the function of each part. The aim is to strengthen the functionality of the entire laminate by strengthening the laminate.

In other words, in the oxygen functional part, the hydrophilic coating layer where the metal body is oxidized is in direct contact with the oxygen/water permeable film.
Oxygen and water can easily reach the hydrophilic coating layer. The deoxidizing ability of the adhesive layer serving as a barrier will be improved.

On the other hand, where there is an adhesive layer in the intermediate layer, the adhesive can be sufficiently thick, and water-soluble polymers can also protect against oxygen.
Since there is no need to add anything that would inhibit adhesion to the water-permeable film, the adhesive's original adhesive strength can be demonstrated, and there is no problem in processes such as lid making and seaming.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are explanatory diagrams showing the distribution state of each adhesive in the embodiment of the present invention.

Claims (1)

[Claims] 1. In a metal body having a hydrophilic coating layer on the surface and an organic resin coating having excellent oxygen and water permeability and impermeable to metal ions, the organic resin coating is adhered to the metal body. Oxygen absorbing functional laminate 2 with excellent adhesion, characterized in that an adhesive layer is partially formed and the non-adhesive portion is used as an oxygen absorbing functional layer. , the adjacent non-bonded parts are isolated, the area ratio of the non-bonded part/bonded part is from 0.1 to 9.0, and the area of the non-bonded part is 2 per piece.
Thickness 2 to 20 cm2 or less
3. The oxygen-absorbing laminate 3 with excellent adhesion according to claim 1, having an adhesive layer of 0 μm. A hydrophilic laminate in which an adhesive is partially applied in advance to a resin coating with excellent oxygen and water permeability. The method for producing an oxygen-removing laminate with excellent adhesion according to claim 1 or 2, characterized in that the method comprises thermocompression bonding to a metal body having a coating layer.