Tinplate should pay attention to what issues in baking

In metal packaging, the vast majority of the use of tinplate coating (inner coating, coating), printing and then baking and then manufactured. Different types of products, a small number of metal drums do not require processing, direct processing and molding. Because metal sheet steel, tin (chromium), etc. will affect the loaded food at a high temperature, which is harmful to human body, so when the food is loaded, it must require a high barrier layer to prevent rust, corrosion, acid and leak. The above requirements. Therefore, whether it is dressed in food, drinks, children's toys, pencil cases, etc., should be produced as required. This requires each printing and canning factory to have a good grasp of each link in the coating, coating, baking, and parts to produce qualified products. The following are only a few issues that should be noticed in the baking of coating iron: Baking is a process flow that coating iron must have. The quality of the baking is good and the quality of the subsequent processing directly affects the quality of the post-processing food. Various quality issues come. Therefore, the coating iron plays an important role in baking. At present, in the equipment for coating iron baking, basically, the heating system can be divided into four major categories: coal heating, kerosene, natural gas heating, and electric heating. No matter what method you use to heat, you must meet the following requirements. Roasting equipment performance and requirements

1. Roasting equipment should have a rapid temperature increase, and the heat capacity should meet the requirements within a short time

2. With enough air circulation and odor removal settings

3. Baking system has a certain degree of sealing and safety

4 baking equipment must hold the relevant department's product certification

5. Baking equipment must have stable and non-deformable properties after use

6. The electrical parts used in baking equipment must meet the national standard requirements

7. Baking equipment should have reasonable use, convenient maintenance and complete mechanical drawings

8. The transmission equipment must be equipped with adjustable timing and reasonable configuration of the air cooling system

Many of the above-mentioned conditions were achieved in the old-fashioned devices in the past. Many manufacturers have been further reforming. The performance of new-type devices often exceeds the above requirements. Many devices are basically equipped with fully automated devices, providing convenience for operators. . But often * some data does not necessarily meet the requirements of the product, but also must carry out various aspects of inspection and process adjustment in the baking process, these are all long-term accumulated experience, once the neglect of the adjustment of baking process, Mixing of various types of products may cause such problems. Therefore, unreasonable baking or insufficient baking may cause food corrosion to occur from time to time. Therefore, the adjustment of the baking process can not be ignored.

Adjustment of baking process

1. According to the material used in the selected food, namely iron plate coating for process adjustment

2. The baking process should be adjusted according to the use process description provided by the supplier, the baking temperature of the coating used, and the amount of coating applied during the production process.

3. According to the performance of the paint, baking time to adjust to the optimal temperature and the best time

4. After the sample test is passed, the first sample shall be sampled and tested during the batch production.

Problems due to irrational baking

1. The heat of the coating iron is insufficient when baking, and the coating film cannot adhere to the substrate when the cover is punched, and the film breaks due to deformation. This is because the paint coating layer does not have enough heat to fully cure, and the cross-linking reaction cannot reach the coating film itself and the film surface tension achieves the best performance. After being filled with food, the micro-cracked or broken parts will corrode for a long time.

2. Quality problems caused by excessively high temperature during baking and excessively long time. If the temperature is too high and the time is too long, the surface of the coating film will be brittle, the surface tension will be lost, the denseness of the coating film and the shrinkage of the micropores will be destroyed, and the surface will be damaged, and the micro-cracks will retreat more. Like bubbles, corrosion will occur soon after food is packed, causing the product to fail.

3. Baking temperature Adjustment of the drying room is unreasonable, resulting in poor adhesion of the coating film and imperfection of the micro-holes. Microbubbles appear after baking, which is caused by improper adjustment of baking temperature. The baking temperature should be from low temperature to high temperature and low temperature. The low temperature zone is the precoating preheating zone of the drying room, mainly combining the temperature of the iron plate itself with the coating layer electrode, so that the low-boiling solvent starts to volatilize, and the curing process is ready for preparation. . Therefore, when adjusting the heat, temperature, and time in the low-temperature zone, quarter factors must also be taken into consideration. If entering the oven immediately into the high temperature area or the beginning of the temperature is too high, the coating film surface is false dry phenomenon, and when the temperature is low, the high boiling point solvent escapes from the coating film little by little, forming small bubbles and reducing the coating on the coating film. After the surface tension, the barrels and cans after processing are peeled and peeled off after being loaded with food.

In short, when the paint iron is baked, it must strictly implement the baking process formulated by various varieties. The new standard QB/T2763-2006, which was implemented on December 1, 2006, has clearly stipulated that relevant companies should be able to thoroughly understand the content of the new standard.