Multi-Layer -Extrusion Large Blow Molding Machine Popular Science

The multi-layer co-extrusion large blow molding machine is a "versatile player" in plastic forming equipment. It produces large hollow products with composite functions by simultaneously extruding and fusing multiple plastic raw materials with different properties, and is widely used in high-end fields such as chemical anti-corrosion containers, food-grade storage tanks, and dangerous goods packaging. Compared with traditional single-layer blow molding machines, it can endow products with multiple properties such as solvent resistance, barrier to penetration, and UV resistance, which is an important technological achievement in response to the improved requirements for packaging functionality in modern industry.
 
The core of its working principle lies in the "multi-layer co-extrusion" technology. The equipment is usually equipped with 3-7 independent extruders, each corresponding to a raw material with specific properties (such as EVOH with strong corrosion resistance for the inner layer, high-strength HDPE for the middle layer, and UV-resistant masterbatch added to the outer layer). During production, different raw materials are heated and melted in their respective extruders to form melts with different properties. Subsequently, these melts pass through a dedicated multi-layer co-extrusion die head, where they are layered and compounded in the flow channels inside the die head, and finally extruded into a tubular parison with a multi-layer structure (for example, a 3-layer structure can realize the functional combination of "barrier layer + structural layer + protective layer"). Then, the parison is sent into the mold, inflated by high-pressure air to fit the inner wall of the mold, and cooled and shaped to form a finished product with multiple properties. During the whole process, the equipment's layer thickness control system controls the proportion of each layer of raw materials by precisely adjusting the screw speed of each extruder (for example, the thickness of the barrier layer can be accurate to 0.1mm), ensuring the functional balance of the composite products.
 
The technical advantages of multi-layer co-extrusion large blow molding machines lie in "function integration" and "material optimization". For the packaging of highly corrosive liquids in the chemical industry, traditional single-layer containers are prone to penetration and leakage, while multi-layer co-extruded products can reduce solvent permeability by more than 90% through the inner EVOH barrier layer. In the field of food storage, the "HDPE + PA" multi-layer structure can not only ensure the strength of the container but also block the entry of oxygen, extending the shelf life of food. In addition, by reasonably matching raw materials, the amount of expensive functional materials can be reduced (for example, the barrier layer only accounts for 5%-10% of the total thickness), improving performance while controlling costs. The equipment has a high degree of automation, equipped with an online thickness gauge and a closed-loop control system, which can real-time monitor the thickness of each layer and adjust automatically to ensure the stability of mass production. A single device can produce large composite products of 100L-10000L, meeting the large-capacity needs of different industries.
 
With the development of high-end manufacturing, multi-layer co-extrusion large blow molding machines are breaking through towards "high layer count and intelligence". At present, 7-layer co-extrusion technology has been commercially applied, capable of producing special containers integrating barrier, flame retardancy, and antibacterial properties. The equipment is equipped with a digital twin system, which optimizes extrusion parameters through virtual simulation, shortening the research and development cycle of new products. At the same time, the compatibility of environmentally friendly raw materials is enhanced, and recycled plastics can be used as the middle layer to realize sustainable production. It can be said that the multi-layer co-extrusion large blow molding machine not only promotes the upgrading of plastic forming technology but also provides innovative solutions for high-end packaging needs in various industries.