Comparison of application and performance of steel drums and plastic drums

Comparison of application and performance of steel drums and plastic drums

With the rapid development of China's petroleum and chemical industries, the total demand for the steel drum market has risen steadily. However, the market share of this form of packaging is being eroded by new packaging containers, such as plastic barrels. For the steel drum industry, the plastic barrel industry is still in a period of gradual growth. However, due to its unique advantages, plastic barrels are showing a post-upper trend.

As a traditional form of packaging, the manufacturing process and application standards of steel drums have been relatively mature. It is widely used as a packaging container for petroleum products, food and light industry, and chemical products. The newly developed plastic barrels are basically consistent with the application fields of steel drums. Only the former is more suitable for the transportation of petroleum products. The latter has advantages in food and light industry and chemical product packaging where capacity requirements are relatively small.

First, the material requirements

The main raw material of the steel drum is steel plate. Generally, the steel plate needs to have a flat surface, low rigidity, small carbon content, and uniform thickness. Auxiliary materials such as oil sealants, gaskets, barrel parts, and coatings are required to make steel drums. Crimping sealant requires good elasticity, high bonding force, many curing components, chemical resistance and process performance.

The raw materials for the manufacture of plastic drums are mainly polyethylene, polyvinyl chloride and modified energy requirements. For example, due to the long material flow, the injection vats usually use a plastic grade with a slightly larger melt index, while the blown vats should take into account the density value, and have a large rigidity and creep resistance. High molecular weight HDPE with anti-wear and environmental stress crack resistance.

Compared with steel, plastic materials have the advantages of light weight, water resistance and moisture resistance, but their barrier properties, heat resistance and impact resistance are far less than steel.

Second, the production process

1. Forming

The manufacturing process of steel drums involves a wide range of technical fields. The following processes are usually required: sheet unwinding, weld edge treatment, barrel welding, barrel flange, barrel body up, roll package, barrel bottom cover forming and pre-rolling, surface treatment, inner surface coating and exterior The surface is painted.

Compared with steel drums, the barrel forming process of plastic drums is simpler. It can be manufactured by an injection molding process or a blow molding process. As with ordinary plastic products, it only needs plasticization, injection molding, cooling solidification and demoulding to complete one injection molding of the barrel. The lid is also manufactured by injection molding. There are general cover and closed cover. When designing the closed cover, the flexibility of the plastic should be fully considered. There is also a convenient insert injection molding----blow molding method, which can form the handle ring and the barrel body at one time. It does not need to use the injection method to form the L-ring, and the obtained integral vat has a high sealing property, and the bonding performance between the handle and the barrel is high.

Since the forming process of the steel drum is relatively complicated, the production cost is much higher than that of the plastic drum. In addition, the steel drum is more likely to have leakage problems. In addition to the possibility of leakage at the mouth of the barrel, the barrel weld and the top of the barrel bottom are not well handled, which will cause similar problems. Statistics show that the leakage and location of steel drums are roughly as follows: the crimping and weld triangles account for 85%; the barrel mouth covers 10%; the barrel welds account for 5%. Since the plastic bucket is formed once, there is no seam in the barrel, which greatly reduces the chance of leakage.

2, external processing

As the outer packaging of the goods, the appearance of the barrel is particularly important. From the perspective of publicity, the performance of plastic barrels is even better.

Before the printing, the steel drum is subjected to the undercoating. The surface of the steel drum is usually coated with a white paint or a clear, colorless paint to be used as a base for printing full-page graphics. As for the plastic drum, except for the part of the colorless and transparent plastic drum, most of the plastics have been added to the plastic masterbatch during the injection molding, and the color is formed once formed. If you want to promote the specific product, you can print it directly on the surface of the barrel.

Since the barrel has a certain volume, it can be printed directly on the surface of the barrel, and only screen printing can be used. Due to different materials. There are also differences in the printing inks used in the two barrels. Steel drums mainly use two-liquid reactive inks, while plastic drums use more volatile drying inks. The printing performance of steel drums is relatively poor. The coating on the surface, or the unclean grease and dust, will affect the adhesion of the ink to the steel drum. The edges of the characters and patterns may be irregular, and there may be burrs and defects. The plastic material has smooth texture and easy to remove dust attached to the surface, which is very convenient for printing. The appearance of the finished plastic barrel is neat and tidy, the edge of the imprint is smooth, the netting is clear and uniform, and the functions of sales and display are combined.

Third, the application market

Steel drums are available in both fully open and closed versions. The 200L steel drum is the mainstream product and there are also convenient barrels as small as 4L. The capacity of plastic drums ranges from 5L to 200L, and even up to 10,000 liters. Plastic drums and steel drums have common application fields, and they also have their own advantages.

1. Petroleum products

At present, although the number of oil pipelines and oil tanks is gradually increasing, steel drums are still the main packaging form of petroleum products, and most of them are 200L closed steel drums.

Steel drums can not be filled when loaded, only 80-90% of capacity. During the injection and pouring process, the gas space in the barrel will be correspondingly reduced or increased. The special breathing valve is designed to maintain the pressure balance inside and outside the barrel to prevent the steel barrel from bursting and leaking. Steel drums perform better than plastic drums in harsh transportation environments. For example, its high temperature resistance is not easy to deform or even melt at high temperatures like plastic drums. It is estimated that the demand for 200L steel drums exceeds 10 million.

200L plastic drums were introduced in China in 1988, and merchants have just begun to question whether they can be used as packaging for petroleum products. Later, plastic drums also have certain advantages in this respect, such as being able to withstand large mechanical pressures, low cleaning costs and reusability. Its market demand is increasing. At present, the annual demand for 200L plastic drums may be more than 1 million. In addition, in recent years, a composite medium-sized bulk container (IBC), commonly known as a ton-packaged plastic container, has specifications of 820L, 1000L and 1250L, and is generally provided with steel frames and trays. Large capacity is its most important feature. This is currently not possible with steel drums.

In addition, there are some restrictions on the application of plastic drums, such as gasoline, trichloroethylene, benzene, toluene and thinner. They are flammable and explosive dangerous goods. When it collides with a non-conductive plastic barrel, it will easily cause static electricity to accumulate, resulting in an explosion accident.

2. Light industry, chemical products, food

The development of China's light industry and chemical industry has provided a vast market for steel drums. Among them, small and medium-sized steel drums are the main demand targets, with an estimated market capacity of more than 10 million. Small steel drums are generally made of tinplate as a raw material for paints, paints, lubricants, etc., while medium-sized steel drums are used for paints, calcium carbide, yellow phosphorus, etc. In particular, 4L rectangular barrels and convenient kegs are popular.

The market share of plastic barrels in this area is expanding. Its biggest potential market is the coatings industry.

The demand for steel drums in the food industry is also expanding. It is estimated that the annual demand in this part of the market is more than 500,000 per year.

Steel drums used for food packaging are mostly open barrels, mainly 200L or slightly larger. Currently, the larger consumers are ketchup, applesauce and honey.

All kinds of seasonings, baking fats, concentrated juices, beans, etc. will be used in plastic drums as outer packaging.

However, it is best not to use plastic buckets for long-term cooking oil. It is used to hold wine or to carry aromatic items, and the time should not be too long.