Analysis of Top Sealing Technology of New Milk Powder Tank

In recent years, with the continuous improvement of the people's living standards and the general society’s emphasis on food nutrition and physical health, various brands, ingredients, and packaged dairy products are filled with shopping mall shelves. The milk powder products, especially metal canned milk powders, have become the current infants and young children due to their high nutritional subdivision, good absorption, high pertinence, convenient use, and relatively long storage time after canning. The most common ideal dairy food for the elderly and the sick.

Therefore, as the demand for milk powder cans increases year by year, in recent years, there have been many large-scale, high-intensity milk cans professional can making plants in Shenzhen, Shanghai, Shandong Laici, and Harbin, and the efficiency is high. Dedicated production line. The market competition of milk powder cans is from south to north and has been fully realized.

According to the survey, the top sealing structure of the most common milk powder cans in the domestic market is mainly divided into two types:

1, the domestic commonly used daughter-mother cover

The daughter cover is mainly composed of three parts: a ring cover (also called a ring cover), a lid cover (also called a core cover, a cover), and an aluminum film. In the production, the stamped aluminum film is sealed together with the ring cap to ensure the top sealing requirements. The seal of the daughter-in-hand cover is completed by the empty can plant, milk powder is filled from the bottom, and the solid can factory finally completes the back cover closure.

When it is opened for the first time, it is necessary to open the lid and tear the aluminum film. When not in use, the lid can be buckled to delay the deterioration of milk powder.

The cover structure is currently the top seal structure commonly used in most domestic milk powder tanks. At the same time, this structure is also widely used in many paint chemical products, tea, biscuits and other metal cans (whether the need for aluminum film can be determined according to the product ).

2. Ring cover and easy tear aluminum film used by Nestle (ALUFIX aluminum solid seal)

LawsonMardonSingen GmbH Production by Rhodes-Matten Sengen

The structure eliminates the lid and uses a hot-melt adhesive to seal a layer of easily tearable aluminum foil with a pull ring on the top of the lid, which also effectively ensures the top seal. When this structure is adopted, an empty can factory is generally responsible for the bottom cover roll closure, and the top cover (the ring cover with the easy-to-tear aluminum foil sealed) is sealed by the solid tank factory after filling the milk powder.

When it is opened for the first time, simply pull the aluminum foil through the pull ring.

Very convenient. When not in use, the plastic cover can be fastened (the milk powder tank currently adopting the sub-female cover structure is also equipped with a plastic buckle cover) to delay the deterioration of the milk powder.

Compared with the above two structures, the sealability and the shelf life of the opened milk powder can be said to be substantially the same due to the use of the plastic buckle cover.

In terms of opening for the first time, Nestle's use of a ring cover with an easily tearable aluminum foil structure undoubtedly has greater convenience. From the cost point of view,

The daughter cover structure includes a ring cover, a dome cover, and an aluminum foil (with a large amount of iron), and the ring cover is affixed with an easily tearable aluminum foil structure including a ring cover and an easily tearable aluminum foil. Since the easy-to-remove aluminum foil or even the ring cover needs a And imports, therefore, the cost of both is relatively high.

A foldable milk powder tank top sealing structure on the Japanese market

This kind of top sealing structure not only does not need the lid cover, also does not need the ring cover, has the good material-saving effect. Rely on the platform formed by the double fold at the mouth of the tank, directly paste ordinary aluminum foil or easily tear aluminum foil to achieve the sealing effect. To provide a new idea for improving the top sealing structure. However, the inadequacies are also obvious. It can be seen from the section that the shape of the structure is relatively complex, there are many manufacturing processes, and the precision of the mold is required to be high. The number of required equipment and investment must be large. In order to reduce the cost of can making and to save iron, we have proposed a new milk can top sealing structure based on the above-mentioned folding structure in Japan.

See Figure 4

According to a rough calculation, the proportion of iron used for the lid in milk cans is about 15%. If the lid is added, then it is more than 20% (calculated as lkg cans). If it can be omitted, the material cost savings will be significant. To this end, we conducted feasibility studies and series of process tests and achieved some preliminary results.

As shown in Figure 3, this new type of milk tank top sealing structure not only eliminates the lid, but also cancels the ring lid, achieving the original intention of saving materials. The platform formed on the top of the can body after necking can be directly

Paste ordinary aluminum foil or easily tear aluminum foil (its sealing performance, convenience of opening, shelf life after opening, etc. are the same as those of the first two structures)

At the same time, the tank mouth strength is also increased, which compensates for the weakened tank mouth strength that may be caused by the cancellation of the ring cover. And compared to Japan

The folding structure, process, process, and equipment are greatly simplified. After the outer edge of the cans is processed, it can be ensured that the plastic buckle cover is tight and reliable, and becomes a reliable support when the bottom cover is sealed.

After the sealing structure is adopted, the equipment to be added mainly includes a can necking machine and a tank foil (foil) machine. There are no ready-made products for these two devices at home and abroad.

According to the results of the current process test, the can neck necking process needs to be arranged after the flanging process and before the rolling process.

In principle, the canning film (foil) process can be completed by an empty can plant, or it can be completed by a solid tank factory after filling milk powder. But taking into account

When filling, it is unavoidable that there will be a small amount of powdered milk remaining on the necking platform, resulting in reduced film strength and reduced sealing performance.

Canned film process should be completed by the empty tank factory should be more ideal. The bottom cover seal is completed by the actual tank factory after milk powder filling.

The above-mentioned new milk powder tank top sealing structure still remains at the process test stage, and the most reasonable necking size still needs further testing and confirmation. Since there are no ready-made products for the key can necking machines and cans film (foil) machines, there may be some technical problems in their design and manufacturing process that need to be solved; the roll bands and sealing molds need to be changed accordingly; aluminum foil or easy tearing How to match raw and auxiliary materials such as aluminum foil and non-toxic hot-melt adhesives; the tank foil application process is best accomplished by the empty can plant, and the empty cans of the bare sticking cartridges are brought into storage, transportation, and subsequent production. How to prevent aluminum foil breakage and open glue need to be considered. Other aspects such as the recognition and acceptance of downstream customers and end users, and the formulation of technical standards are also very important.

After the above problems are better resolved, we believe that this new type of milk tank top seal structure due to its material-saving side

The advantages of the surface will inevitably have a good market application prospects. Not only can it be used in milk powder tanks, but it can also be applied to other powdered, granular content cans that are at room temperature without vacuum requirements.

In the above work, especially in the test tanks, process flow, and the provision of relevant information, etc., they were strongly supported by factories and associations such as Shenzhen Daman Can Making, Harbin Yintie Products, Canned Industry Association, and Metal Container Committee. In this regard, thanks!