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The "Process Code" for Disposable Plastic Containers: 3 Sheet-Extrusion Processes Tailored to Different Needs
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The clear cups used for bubble tea, the takeaway food containers, and even the bowls for instant noodles—these seemingly ordinary disposable plastic items actually rely heavily on "thermoformed sheets" for support. Such sheets must withstand high-temperature molding while balancing cost-effectiveness with practicality. And of course, the extrusion process tailored specifically for these sheets requires careful consideration—mainly falling into three key methods: "conventional extrusion," "multi-layer co-extrusion," and "cast film." Today, we’ll reveal the logic behind the process choices that shape each type of container.
I. Conventional Extrusion Sheet Process: Crafting "Affordable, Must-Have" Containers
The most common disposable containers we see in our daily lives—such as the soy milk cups from convenience stores or the takeout soup bowls sold on the street—are mostly made from sheets produced using conventional extrusion techniques.
Its advantages are very straightforward: Low cost, highly adaptable.
During production, PP (polypropylene) and PE (polyethylene), these common plastic pellets, are fed into an extruder. After being heated and melted, they are extruded through a flat die. The resulting material is then passed through a three-roll calender to flatten and cool, allowing it to set into shape. This process yields sheets with a thickness ranging from 0.2 to 1.5 mm—perfect for disposable containers, as the thickness strikes the ideal balance: not too thin to easily deform, yet not so thick as to waste material unnecessarily.
Moreover, this process doesn't demand high-quality raw materials and doesn't require the addition of complex ingredients. Production efficiency is also fast. , can meet High-volume demand for affordable containers 。 Like transparent PP milk tea cups, white PE takeout bowls, and simple plastic food containers, As long as there are no special requirements (such as microwave heating or leak-proof features), it’s basically all its "masterpiece." 。
II. Multi-layer Co-extrusion Sheet Process: Solving the "Functional Challenge"
If you encounter a situation that requires “High-temperature resistance” “Leak-proof” “Corrosion-resistant” For containers where the standard extrusion process is no longer sufficient, this is precisely when the multi-layer co-extrusion process steps in to deliver the necessary performance.
Its core logic is “ Layered Composite “：Using multiple extruders to melt different types of plastics separately, then layering them together through a composite die to create a sheet where ‘one layer equals one function.’”
For example, take-out food containers designed for microwave heating use a "PP inner layer + PET outer layer"—PP is safe for food contact, while PET can withstand microwave temperatures as high as 120°C without softening or deforming. Meanwhile, leak-proof containers meant for soups and porridge include an additional EVOH barrier layer sandwiched between two layers of PP, effectively preventing liquid seepage and eliminating worries about soup spills. And for cups intended to hold vinegar or juice, a PP+PE composite material is used; PE provides excellent resistance against acidic and alkaline corrosion, ensuring that beverages remain fresh and free from cross-contamination of flavors.
Simply put, as long as the container has "special requirements," the multi-layer co-extrusion process can meet these needs one by one by combining different materials.
3. Cast Film Process: Crafting "Elegant Aesthetic" Containers
Some disposable containers strive for “Thin, Transparent, Beautiful” For example, tasting cups from milk tea shops or small cake boxes from dessert stores—this is exactly when the casting process comes in handy.
Its characteristic is “High precision, high transparency” : The plastic melt is extruded through a precision T-die, flowing evenly onto a mirror-like cooling roller for instant cooling and shaping. This process produces sheets with a thickness that can be precisely controlled between 0.1 and 0.3 mm—thin yet perfectly uniform—and boasting a surface as smooth as a mirror, with exceptionally high transparency. For instance, when used to package ready-to-drink milk tea, the vibrant colors shine through clearly; meanwhile, it highlights the exquisite beauty of miniature cakes at a glance, making them utterly irresistible.
Moreover, the ultra-thin feature also helps save materials while ensuring strength. Reduce costs , perfect for doing Small capacity, high aesthetic appeal The exquisite container.
| Serial Number | Container Type | Core Requirements | Using the process | Typical example |
|---|---|---|---|---|
| 1 |
Affordable, Must-Have Style |
Low cost, no special features | Common Extrusion Sheet Processing Method |
PP milk tea cups, PE takeout containers |
| 2 | Upgraded Version with Enhanced Features | High-temperature resistant, leak-proof, and corrosion-resistant | Multi-layer co-extrusion sheet process | Weibo meal boxes, leak-proof meal boxes |
| 3 | Elegant and visually appealing style | Ultra-thin, highly transparent, with a sleek appearance | Cast Film Manufacturing Process | Tasting cups, dessert packaging boxes |
Turns out, those tiny disposable plastic containers hold so many clever design secrets behind the scenes! Choosing the right manufacturing process not only ensures the container is both functional and safe, but also helps keep costs under control—this is precisely why containers designed for different scenarios feel—and perform—so uniquely distinct when you touch or use them.
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