Which Is Better, Low-Temperature Injection Molding or High-Temperature Hot Pressing?
author: Iris
2025-08-07
1. What Is Low-Temperature Injection Molding? What Is High Temperature Hot Pressing?
First of all, let's figure out what these two practices are, as if one is “plastic particles melted and injected into the box”, and the other is "heating the plastic sheet pressed into the box.
What Is Low-Temperature Injection Molding?
Low-temperature injection molding actually to heating the plastic particles to almost 200 ℃, like beating soybean milk into a paste, and then beating it into the mold to set the shape. This way is suitable to make the kind of strong, separated, has a lid lunch box, such as a microwave oven special three compartments lunch box, sealed box, etc., take-out food plastic containers. If the requirements are relatively high, we usually use this way to do.
What Is Hot Pressing?
High-temperature hot pressing involves taking a whole sheet of plastic, heating it up to over 300 degrees, and then pressing it into a mold to set the shape. Imagine baking cookies in a mold, a press, one, this way is how it comes. This method is suitable for making disposable and simple takeout boxes for food, such as packaged lunch boxes, transparent lids, plastic bowls, etc.
A Brief Comparison
| Process | Temperature | Fast or slow molding | How long does the mold last | Suitable materials |
| Low-temperature injection molding | 180℃-240℃ | Fast molding | Long mold life | PP, PS |
| High-temperature hot pressing | 280℃-320℃ | Slightly slower | Mold life in general | PET, PP, PLA |
3. Which One Is More Environmentally Friendly and Safer?
To make a box, we not only need to see whether it is cheap or not, but also need to see whether it will affect food safety and pollute the environment.
Injection Molding: Clean and Odorless, Suitable for Export
One advantage of low-temperature injection molding is that the temperature is not so high, the material is not easy to degrade out of the odor, plastic flavor is also less, it is very suitable to be used to do direct contact with food packaging boxes, especially to export to Europe and the United States take-out container manufacturers, this process is very popular.
Hot Pressing: Suitable for Environmentally Friendly Materials, Such as PLA
Nowadays, the popular environmental protection materials, such as PLA, CPLA, mainly rely on high-temperature hot pressing to do. These materials are afraid of long-term high-temperature churning, so the hot press is more stable. However, if the high-temperature hot pressing is not well controlled, it is easy to have the problem of yellowing and odor of plastic, so the operation requirements are also a little higher.
5. What Do You Think from the Manufacturer's Point of View?
Do not just choose the box process, or choose a way to make money.
Injection Molding Is Suitable for Long-Term Branding
Low-temperature injection molding equipment, molds are quite expensive, but the advantage is that the mold can be used for a long time, and product quality is more stable, and later production costs are not high. Suitable for export, chain restaurants, and other long-term customers.
Hot Pressing Is Suitable for Business Start-Up
Hot pressing equipment is cheap, easy to operate, and very suitable for small and medium-sized factories to start with. If the customer is the kind of orders, but the unit price is low, it is very suitable for hot pressing to respond quickly to the market.
2. What Is the Difference Between the Made Lunch Boxes?
With different processes, the feel, sealing, shape, and heat resistance of the boxes are different.
Injection Molded Boxes Are Stronger and Have Better Details
Take-out food plastic containers made by low-temperature injection molding are very neat in shape, and the edges and corners are well done. Boxes with multiple compartments and tightly sealed lids are basically injection molded. This kind of box not only can hold hot rice, but also can be put into the refrigerator, and even microwave heating is no problem. But the injection mold is more expensive, the factory has to invest a lot of money at the beginning, and the plastic particles should be selected that kind of good fluidity, can be injected into the mold.
Hot Pressing Box Cheap, Fast Shipping
High-temperature hot pressing is out of the box; the advantage is fast, cheap, and suitable for a kind of box that is not so complex, such as takeaway stores unified with the kind of plastic lunch boxes. The mold structure is simple, good maintenance, a pressure of one, especially suitable for mass production of factories, such as the kind of thousands of shipments of single product boxes is very suitable. The shape is not so precise; sometimes the edge will be a little thin, and the lid may not be as tight as the injection molded box.
4. What Scene Is Suitable for Which Process?
Different users and different usage scenarios have different requirements for the box, so you can't generalize.
| Scene | Recommended Process | Why? |
| Fast food chain stores | Injection molding | Support compartmentalization, can be customized LOGO, looks more advanced |
| Takeaway platform | Hot pressing | Low cost, fast shipping, versatility |
| Hospital/airplane meals | Injection molding | Requirements: sealing, leak-proof, and can be heated |
| Schools/unit canteens | Hot pressing | Cheap, throw away after use, simple, and practical |
If your customers value brand image, good-looking packaging, it is recommended to do injection molding boxes; but if they want to be affordable and can be supplied in large quantities, hot press is more appropriate.
Where to Buy?
Huizhou Yangrui Printing & Packaging Co., Ltd., established in 2014, offers a variety of materials, including PP, PET, PLA, and MFPP. We hold numerous international certifications, including ISO9001, FDA, and BRC.
Contact Information:
Phone: +86-159 8949 1653
Email: sales@yrpak.com
Email: sales@yrpak.com
References
- Plastics Technology (2021). Injection Molding vs. Thermoforming: What’s Best for Food Packaging?
- Food Packaging Forum (2023). Safety Assessment of Plastic Food Containers in Heat Processing.
- European Bioplastics (2022). Biodegradable Plastics in Food Service Applications.
- MarketsandMarkets (2024). Takeaway Food Packaging Market - Global Forecast to 2030.
- State Administration for Market Regulation (2022). General Safety Requirements for Food Contact Materials (GB) 4806.1-2016.
Are Plastic Take-Out Food Containers with Lids Safe? How Do I Know if They Have BPA?
Why Is Lightweight the Next Important Direction for the Plastic Take-Out Food Box?
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