JPS61295396A - Material for can having deoxidizing power - Google Patents

Abstract

PURPOSE:To efficiently remove residual oxygen in a can by plating one side of a surface treated steel sheet or an Al plate corresponding to the inside of a can with a specified amount of one or more among Fe, Zn and Mn. CONSTITUTION:A surface treated steel sheet such as tin plate, a tin-free steel sheet or an Ni plated steel sheet is used as a material for a can. An Al plate is used as a material for a can cover. One side of the surface treated steel sheet or the Al plate corresponding to the inside of a can is plated with one or more among Fe, Zn and Mn by 0.5-20mg/dm<2>. Fe, Zn and Mn react with residual oxygen in a can, forming oxides, so the residual oxygen in the can is removed to prevent deterioration in the quality of good or drink in the can.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to surface-treated steel sheets for cans, such as tin-plated steel sheets, nickel-plated steel sheets, and chrome-plated steel sheets, which are currently widely used as steel sheets for cans, as well as the surface of aluminum sheets. iron (
Fe), zinc (Zn), or manganese (Mn) is applied to the container to give it the ability to remove oxygen present in the sealed container by utilizing the self-corrosion reaction of the metal. This relates to materials for cans.

The present invention aims to maintain the quality of the contents by removing residual oxygen in cases where the quality of the contents is significantly impaired by the oxygen present in the sealed container. This is a technology that is widely applied in the field of cans.

As is well known, oxygen is a strong oxidizing agent, so if it is placed in a container with food, it will oxidize the food and deteriorate its quality1. It is known to cause the oxidation and decomposition of natural pigments and aroma components (Beveridge Japan, No. 39,
p. 23-35) In addition, it promotes corrosion on the inside of the can, and in the case of tin-plated steel sheets, it causes problems such as excessive tin elution and the generation of can odor.For example, excessive residual oxygen in the head space causes beer Reducing this residual oxygen (headspace and dissolved oxygen) has been a long-standing concern in the food industry, as it causes deterioration in taste and blackening and corrosion at the liquid interface of canned mandarin oranges.

Conventional Methods Oxygen present in containers is mainly derived from air mixed in when sealing the contents, and in order to reduce the amount of air enclosed, conventional methods have been to (1) pre-heat the contents and heat them up. How to drip and immediately seal (fruit juice, etc.),
(2) Method of heating and degassing after sealing (solid food),
(3) Method using a vacuum sealing device (vacuum fist seamer), (4) Steam flow seamer method that blows pressurized steam into the head space of the can, (5) Sealing while flowing carbon dioxide gas or nitrogen. There are ways to do this.

These conventional techniques each have -long and -short sides, but (
Methods 1) and (2) are specific to the contents to be heat sterilized, and method (3) is limited to foods with little liquid because the liquid is sucked up when the amount of contents is large. Since (4) uses steam, it cannot be applied to, for example, beer or carbonated drinks, and (5) has the disadvantage of being expensive.

Therefore, for example, for beer, etc., methods are used such as sealing the container as it is or flowing a small amount of carbon dioxide gas. Therefore, even if the oxygen in the can is carefully sealed, in the case of beer, for example, the headspace is 350 - can (normal volume 2
There is an average of 0.16 g (0.231 g) of radish in 4), and the maximum (equilibrium concentration) is 0.28 ppm in beer.
(20°C) dissolved oxygen will be present. These enclosed oxygen reacts with the organic matter in the beer relatively quickly and decreases to a fraction of what it is in, for example, a week (depending on the storage temperature, the higher the temperature, the faster), resulting in deterioration of taste, browning, etc. Changes in taste, color, aroma, etc. caused by this are particularly significant in unpasteurized draft beer, and are a major quality problem.

Problems to be Solved by the Invention In order to solve the above-mentioned problems, the present invention recognizes that it is unavoidable that a certain amount of oxygen is sealed inside the can, and uses the can body to remove this oxygen. With this in mind, they discovered that oxygen can be effectively removed by utilizing the corrosion reaction inside the can, and developed a material for cans that has an ability to remove oxygen.

Means for Solving the Problems The present invention provides a surface treatment method for cans with a surface treatment of 0.5 to 20 mg/dffI as a basis weight on the surface of a surface-treated steel sheet for cans or an aluminum sheet for cans.
This is a material for cans having oxygen scavenging ability, characterized by being plated with one or more of Fe, Zn, and Mn.

It is well known that oxygen and water are required simultaneously for the corrosion reaction of metals. Taking iron as an example, the reaction is expressed as follows.

There is sufficient moisture in the can, and for example, to fix 020.18+si as rust through the above reaction, do the following:
This means that 0.53 mg of Fe should be consumed. If a can lid is used for this, for example, in a 350 can (can lid area: 32 cm2), the thickness of the rust that will be formed will be at most:
800 people (Fe203 *H20 density 3g/C11
3), and in order to form a rust layer with good adhesion,
In weakly acidic aqueous solutions such as beer, redissolution is minimal. However, if a trace amount of Fe2+ is a problem, painting is optional.

In this case, with a normal coating system (such as an epoxy resin), although moisture permeation is not a problem, the oxygen permeation rate is low, so oxygen permeation becomes the rate-determining process for the reaction (1). Therefore, it is desirable to use a paint with good oxygen permeability, such as an oleoresinous paint or a silicone rubber paint.

Here, the effect of removing 02 by the reaction of formula (1) above is extremely remarkable, and in a closed container, 0, 18+
More than 90% of the 02 of d is removed in 24 hours, and the oxygen concentration can be quickly lowered to a level that does not have any adverse effect on quality.

The present inventors conducted experiments on various metals other than Fe, and found that Zn and Mn had the same effect as Fe, but A1
．． With the latter metals, such as 0M, which we found to be ineffective with Cr, Sn, and Ni, a stable oxide film is formed, so corrosion reactions do not occur (or are extremely slow).
Therefore, it is not suitable for rapid oxygen removal, which is the object of the present invention.

Therefore, for the sole purpose of removing oxygen, iron, zinc or manganese plates can be used as they are, but they also have the basic properties as can materials (mechanical strength, workability, rust resistance, corrosion resistance to the contents). In order to meet these requirements, the substrates should be surface-treated steel sheets and aluminum plates for cans, such as tinplate (tin-plated steel sheets), tin-free steel (chromium-chromate steel sheets), and nickel-plated steel sheets, which are currently used as materials for cans. As a treatment, the above-mentioned Fe, Zn, and Mn
Flash plating is the easiest and most economical method.

Fe, Zn, and Mn may be plated alone or two or more of them may be plated at the same time, and alloy plating is also effective. F of the plated steel plate and aluminum plate for the container
For plating Zn and Mn, typical plating methods for these metals can be applied as they are. For example, Fe plating uses a treatment bath based on ferrous sulfate, Zn plating uses a bath based on dipped zinc sulfate, and Mn plating uses a bath based on manganese sulfate. In this case, conventionally known surface-treated steel plates for cans or aluminum plates for cans used as the material of the present invention can be used.

For this type of application, tin-plated steel sheets known as tinplate, nickel-plated steel sheets, chrome-plated steel sheets, etc. are used, and in addition to these, thin nickel plating, nickel-phosphorus, nickel-iron plating, etc. are used. Steel plates with tin plating on top are known, but surface-treated steel plates with such a multilayer structure can also be used as the material.

Also, plated materials (tin plated steel plate, nickel plated steel plate,
Since the deposition current efficiency differs slightly depending on the type of plate (chrome-plated steel plate, etc. and aluminum plate), it is desirable to determine the current efficiency in advance when determining the basis weight. It has been chromate treated, and although there is some difference in current efficiency depending on whether or not this treatment is applied, it was confirmed that there is no problem with the wood quality.

In the present invention, it is not necessary to strictly control the amount of Fe, Mn, and Zn deposited, but it is meaningless to deposit more than the amount required for oxygen removal, and the excess amount will at least cause corrosion inside the can. Since this is undesirable from the viewpoint of oxidation, it is sufficient to deposit the minimum amount of oxygen depending on the amount of oxygen normally sealed in the target can.

In the present invention, the amount of adhesion can be reduced from 0.5g/d to 20B/d.
The amount specified for dm2 was calculated based on the actual amount of oxygen that can be sealed in a normal can, and Fe
, Zn, and Mn, the amount of plating required will vary, but as long as it is within the above range, it will cover a large man's food can.

Therefore, as is clear from the purpose of the present invention, plating on one side is sufficient to remove oxygen inside the can, and the outer surface of the can can be left as a normal surface (or rather, it is preferable).
For Zn and Mn, single-sided plating is practical. It was also confirmed that oxidation of the metal surface during baking the paint did not affect the oxygen removal effect.

Examples of the present invention will be described below.

Example 1 Non-chromate material of #50 tinplate (basis weight 0.47LBS/B, B,) was mixed with FeSO4.7H20250g/
Q, FeCQz・4H2042g/l, NIl [
In a plating bath of 120 g of 4Ci (temperature: 40° C.), cathodic electrolysis was carried out for 2 seconds at IOA/da2 using iron as a counter electrode to obtain a tin-based Fe-plated steel plate with an Fe deposition amount of about 3.5 mg/da2.

This was used for the lid of a 350cm beer can (area 32cs+2) (at this time the can body was a painted tin can), and beer was brewed in carbon dioxide gas with the oxygen concentration controlled at 0.8voj1% (11, LsgOz/11). was enclosed and the headspace was maintained at approximately 24all. At this time, the gauge pressure in the head space was about 1 kg/Cm2, and the absolute amount of 02 was 0.55 mg sealed in the head space.

The amount of dissolved 02 in the beer measured after 10 minutes in a separately prepared can was Q, lppm. Hold this sealed can at 20°
After being kept in constant temperature water of C for 24 hours, 02 in the headspace and beer was measured and found to be 0.04 respectively.
g and 0. O5ppm, about 1 in headspace
/12. It decreased to about 172 in beer, indicating a remarkable oxygen scavenging effect. In addition, the iron surface of the can lid was colored with a light edge color.

Example 2 Chromate treated #50 tin plate was treated with ZnSO4.7
H20240g/i, NHa Cf! 15g/ (
j, Al1 (SO4)3 ”18H2030g/1
In plating bath 1 (at room temperature), with a zinc plate as the counter electrode, IOA/
Cathodic electrolysis for 1.5 seconds at d+s2, 5.0mg/da2
A tin-undercoated Zn-plated steel sheet was obtained. Using this as a can lid, beer was sealed in carbon dioxide gas of 11.4mgo27λ in exactly the same manner as in Example 1, and the head space was set to about 24.
It was held in place.

Headspace and dissolved 02 measured after 24 hours
The amounts are 0.08 mg and 0.08 mg, respectively. O5ppm, about 1/10 in headspace. Approximately 1/in beer
2, and a remarkable deoxidizing effect was observed. Moreover, the Zn surface of the can lid was colored white.

Example 3 Non-chromate treated #50 tin plate was treated with Mn5Oa
・4H20100g/i, (N&)2sOa
Cathode electrolysis was carried out for 1 second at 2OA/as2 using carbon as a counter electrode in a plating bath containing 75 g/Q and 80 g of NH4SCN (at room temperature) to obtain a tin-undercoated Mn-plated steel sheet having an Mn content of about 5.2 mg/d2. Using this can lid, beer was sealed in 11.4 mg02/it of carbon dioxide gas in the same manner as in Example 1, and the head space was maintained at about 24 mm.

Headspace and dissolved 02 measured after 24 hours
The amounts decreased to 0.042 mg and 0.055 pp, respectively, and a remarkable oxygen scavenging effect was observed.

Example 4 Fe plating was performed on a previously plated steel plate (Ni 700 mg/rn' + chromate treatment) under the same conditions as Example 1,
A nickel-based Fe-plated steel plate was obtained with an Fe adhesion amount of approximately 3.8 mg/dm2. Using this as a can lid, beer was sealed in 11.4 mg02/u of carbon dioxide gas in the same manner as in Example 1, and after 24 hours, the head space and dissolved zero
Two amounts were measured. The values are 0.04mg and 0.055
The oxygen content decreased to ppa+, and a significant oxygen removal effect was obtained.

Example 5 Zn plating was carried out on a Ni-plated steel plate (formerly 700 mg/m" + chromate treatment) under the same conditions as in Example 2.
Nickel base Z with adhesion amount of 5.1 mg/da2
An n-plated steel plate was obtained. This was used as a can lid, and beer was sealed in 11.4 mg02/II carbon dioxide gas in the same manner as in Example 1. The amount of 02 in the headspace and beer measured after 24 hours was 0.044 mg and 0.05, respectively.
A remarkable deoxidizing effect was observed in the pp layer.

Example 6 Tin-free steel (metallic chromium 100 mg/rn'
, Fe plating was performed on hydrated chromium oxide (15 mg/d+a2) under the same conditions as in Example 1, and the amount of Fe deposited was 3.
A chromium-undercoated Fe-plated steel plate with a weight of 61 mg/d+m2 was obtained. This was used for a can lid, and as in Example 1, 11.4mg0
Beer was sealed in 2/l carbon dioxide gas. The amount of 02 in the head space and beer measured after 24 hours was 0.055 g and 0.05 pp, respectively, indicating a remarkable oxygen scavenging effect.

Example 7 Tin-free steel (metallic chromium 100 mg/m''
Zn plating was carried out on chromium oxide (15 mg/da2) under the same conditions as in Example 2, and the amount of Zn deposited was 4.
A chromium-undercoated Zn-plated steel sheet with a layer 2 of 8 mg/d was obtained. This was used for a can lid, and as in Example 1, 11.4mg02/
Beer was encapsulated in carbon dioxide gas for 24 hours, and the head space and dissolved amount were measured 24 hours later. The values decreased to 0.048 layer g and 0.052 ppm, respectively, and a remarkable deoxidizing effect was obtained.

Example 8 A rolled aluminum plate for can lids was plated with Fe under the same conditions as in Example 1, and the amount of Fe deposited was 3. Orag
/dm2 Fe-plated aluminum plate was obtained. This was used as a can lid, and beer was sealed in 11.4g02/i of carbon dioxide gas in the same manner as in Example 1. After 24 hours, the head space and amount of dissolved O2 were measured.
0+sg and 0. The oxygen content decreased to 4 lppm, and a remarkable deoxidizing effect was obtained.

Example 9 Z was applied to a rolled aluminum plate for can lids under the same conditions as Example 2.
N plating was performed to obtain a Zn-plated aluminum plate with a Zn adhesion amount of 5.3 mg/d2. Using this as a can lid, beer was sealed in 11.4 gO2/l of carbon dioxide gas in the same manner as in Example 1, and 24 hours later, the head space and amount of dissolved O2 were measured. The value is 0.048mg each
and 0. The oxygen content decreased to 4 11ppm, and a remarkable oxygen removal effect was obtained.

Example 1O Tin-based Fe-plated steel plate (#50 tin, Fe 3.5m
g/d, 2) with a bar coater to a thickness of about 5 #L, and baked at 200°C for 10 minutes. Using this coated plate as a can lid, beer was sealed in 11.2-g0z/11 carbon dioxide gas in the same manner as in Example 1, and the head space and the amount of 02 in the beer were measured after 24 hours. However, each 0.04
5 mg and 0.0 θppm, and a remarkable deoxidizing effect close to that of an uncoated board was obtained.

Example 11 #50 tinplate chromate treated material is FeC22118
) 12027g/l, zinc birophosphate 56g/9
．． ．． Birophosphate 174g/9, iron 5g/1. Cathodic electrolysis was carried out for 2 seconds at 6 A/da2 at 80°C in a plating bath containing 20 g/Q of zinc, and 4.8 mg/ds2 of Fe (30
%)-Zn (70%) tin-based Fe-Zn with alloy layer
An alloy plated steel plate was obtained. Using this as a can lid, beer was sealed in 11.4 mg 02/11 carbon dioxide gas in exactly the same manner as in Example 1, and the head space was maintained at about 24 mm. 24
The head space and amount of dissolved O2 measured after the time were 0.0511 g and 0.052 ppm, respectively, indicating that a remarkable deoxidizing effect was obtained.

As described in detail, the can material of the present invention has a remarkable deoxidizing effect.

Claims (3)

[Claims] (1) Apply F of 0.5 to 20 mg/dm^2 as a basis weight on the surface of a surface-treated steel sheet for cans or an aluminum sheet for cans.
A can material having oxygen scavenging ability, characterized by being plated with one or more of e, Zn, and Mn. (2) The oxygen scavenging ability as set forth in claim (1), wherein the surface to which Fe, Zn, and Mn plating is applied is one side corresponding to the inside of the can of a surface-treated steel sheet for cans or an aluminum sheet for cans. Can material with. (3) A material for cans having an oxygen scavenging ability according to claim 1 or 2, wherein the surface-treated steel sheet for cans is a tin-plated steel sheet, a nickel-plated steel sheet, or a chrome-plated steel sheet.