You may have also encountered that the beer bottle caps you bought are rusted. So what is the reason? The reasons for the rust on beer bottle caps are briefly discussed as follows.
The beer bottle caps are made of tin-plated or chrome-plated thin steel plates with a thickness of 0.25mm as the main raw material. With the intensification of market competition, another function of the bottle cap, namely the trademark of the bottle cap (color cap), has become more prominent, and higher requirements have been put forward for the printing and use of the bottle cap. Sometimes the rust on the bottle cap will affect the brand image of the beer. The mechanism of rust on the bottle cap is that the exposed iron after the anti-rust layer is destroyed reacts electrochemically with water and oxygen, and the degree of rust is closely related to the material of the bottle cap, the process of internal anti-rust layer coating and the surrounding environment.
1. The influence of baking temperature or time.
If the baking time is too long, the varnish and paint applied on the iron plate will become brittle; if it is insufficient, the varnish and paint applied on the iron plate will not be completely cured.
2. Insufficient coating amount.
When the bottle cap is punched out from the printed iron plate, the untreated iron will be exposed at the edge of the bottle cap. The exposed part is easy to rust in a high humidity environment.
3. The capping star wheel is not vertical and asymmetrical, resulting in rust spots.
4. During the transportation of logistics, the bottle caps collide with each other, resulting in rust spots.
5. The internal wear of the capping mold and the low height of the capping punch will increase the wear of the cap by the capping mold.
6. After the bottle cap with water is pasted with aluminum platinum or immediately packed (plastic bag), the water is not easy to evaporate, which accelerates the rust process.
7. The bottle exploded during the pasteurization process, which lowered the pH of the water and easily accelerated the rusting of the bottle cap.
Combined with the above reasons, the following aspects should be focused on:
1. Strengthen the appearance and corrosion resistance inspection of beer bottle caps before entering the factory.
2. During the inspection process, especially when changing suppliers, the inspection of the corrosion inside the bottle cap after beer sterilization should be strictly strengthened.
3. Strictly implement the cap indentation detection, and the packaging workshop should check the capping quality at any time.
4. Strengthen the inspection of the filling machine capping star wheel and capping mold, and clean up the bottle in time after crushing.
5. The manufacturer can blow the residual moisture of the bottle cap before coding, which can not only ensure the coding quality (coding on the bottle cap), but also play a positive role in the rust prevention of the beer bottle cap.
In addition, the use of chrome-plated iron has a stronger rust prevention ability than galvanized iron.
The main function of the beer bottle cap is, first, it has a certain sealing property, ensuring that CO2 in the bottle does not leak and external oxygen does not penetrate, so as to maintain the freshness of the beer; second, the gasket material is non-toxic, safe and hygienic, and will not have any effect on the flavor of the beer, so as to maintain the taste of the beer; third, the trademark printing of the bottle cap is excellent, which plays an important role in the brand, advertising and product maintenance of the beer; fourth, when the brewery uses the bottle cap, the bottle cap can be used for high-speed filling machines, and the lower cap is unobstructed, reducing the cap damage and beer damage. At present, the criteria for judging the quality of beer bottle caps should be:
I. Sealing:
Instantaneous pressure: Instantaneous pressure ≥10kg/cm2;
Chronic leakage: According to the standard test, the chronic leakage rate is ≤3.5%.
II. Gasket odor:
Safe, hygienic and non-toxic. The gasket flavor test is done with pure water. If there is no odor, it is qualified. After use, the odor of the gasket cannot migrate into the beer and cause any impact on the flavor of the beer.
III. Bottle cap characteristics
1. The paint film loss value of the bottle cap, the high-quality product requires ≤16mg, and the paint film loss value of the tin-plated iron bottle cap and the full-color chrome-plated iron bottle cap is ≤20mg;
2. The corrosion resistance of the bottle cap usually meets the copper sulfate test without obvious rust spots, and must also delay rusting during normal use.
IV. Appearance of bottle cap
1. The trademark text is correct, the pattern is clear, the color difference range is small, and the color between batches is stable;
2. The pattern position is centered, and the center distance of the deviation range is ≤0.8mm;
3. The bottle cap must not have burrs, defects, cracks, etc.;
4. The bottle cap gasket is fully formed, without defects, foreign matter, and oil stains.
V. Gasket bonding strength and promotion requirements
1. The bonding strength of the promotional bottle cap gasket is appropriate. It is generally not easy to peel off except for the requirement to peel off the gasket. The gasket after pasteurization does not fall off naturally;
2. Usually the bonding strength of the bottle cap is appropriate, and the bottle cap of high-quality products can pass the MTS (material mechanics test) test.
Post time: Aug-30-2024