Plastic Misconceptions and Recycling Symbols：
Many may not realize that a key piece of information is often right at our fingertips—or rather, at the bottom of our plastic containers. If you look closely, you will find a triangular symbol made of three arrows—a universal recycling symbol. There is widespread misunderstanding about the number inside this triangle. The belief that it indicates the plastic’s recyclable frequency is, in reality, not accurate. In fact, this number identifies the resin type used as the primary raw material in the plastic product. It’s like a dedicated ID number for plastic—it governs what the material is like, how it can be used safely, and the right approach to recycling it. Correctly interpreting this symbol is the first step toward responsible consumption and personal safety.
In-Depth Analysis of Common Plastic Materials and Safe Use Guidelines
1.1 PET (01): Characteristics and Usage Notes
You’ll often find PET in everyday products: mineral water bottles, carbonated beverage bottles and a range of food containers. It is lightweight, transparent, and provides good barrier properties, but has limited heat resistance, typically tolerating temperatures up to only 70°C. This material is not for hot liquids or heating. It will warp quickly if exposed to heat and it may even release hazardous substances including antimony. Scientific studies further indicate that prolonged use or repeated exposure to high temperatures can accelerate the material’s aging, increasing the risk of chemical migration. For safety, PET bottles and containers should be recycled right after use. Don’t reuse them for long-term food storage.
1.2 HDPE (02): Properties and Usage Suggestions
It is usually opaque or semi-transparent, relatively rigid, and can withstand temperatures up to approximately 110°C. It also offers good chemical resistance and durability. Some HDPE items carry a food-grade label, yet their surface can trap bacteria that are hard to remove completely. So even food-safe HDPE containers should be used for specific purposes only. Don’t repurpose cleaning product bottles for food storage, this can prevent chemical residue and bacterial cross-contamination.
1.3 PVC (03): Common Uses and Vinyl Chloride Risks
PVC stands for Polyvinyl Chloride. It is a versatile plastic. However, PVC often contains plasticizers such as phthalates added during production to improve flexibility. These additives, along with vinyl chloride monomer (VCM), may leach out when exposed to heat or oils, posing health risks. Prolonged exposure can be harmful. It may damage the endocrine system, liver and reproductive health. It is best to avoid using PVC containers for hot or oily foods, and exercise particular caution with products intended for children.
1.4 LDPE (04): Common Applications and High-Temperature Precautions
LDPE stands for Low-Density Polyethylene. It is mainly used to make plastic bags, and it’s also used for cling film and flexible packaging. It is soft, transparent, and offers good sealing performance. However, its heat resistance is relatively low—it begins to soften and melt at temperatures above 110°C, potentially releasing chemical compounds. Therefore, using LDPE cling film to cover food during microwave heating is not safe. Always keep LDPE products away from direct heat and avoid using them to wrap oily foods for cooking.
PP (05): Excellent Heat Resistance and Versatility
Polypropylene, or PP for short, is commonly found in microwave-safe food containers, yogurt cups, juice bottles and lunch box lids. It’s the only widely accessible plastic safe for microwave use. Its heat resistance goes up to 160°C. PP is chemically stable, scratch-resistant, and easy to clean. These qualities make PP containers both safe and durable enough for repeated use, offering an eco-friendly alternative to disposable packaging. When selecting food containers, look for the “05” symbol and “microwave-safe” labeling to make a healthier and more sustainable choice.
1.5 PS (06): Material Properties and Beverage Selection Tips
It provides good insulation and is low-cost, but is relatively brittle and heat-sensitive, tolerating temperatures below 90°C. When in contact with strong acids such as citrus juice, alkalis, or greasy foods, PS may break down and release styrene monomer. Therefore, PS cups are not suitable for hot drinks, acidic beverages, or carbonated drinks. Consumers buying takeout beverages should check the cup material and opt for safer alternatives like paper or PP when possible, and minimize contact time with hot liquids.
1.6 OTHER (07): Diverse Plastics and the BPA Concern
The “07” category covers a range of other plastics, including PC (polycarbonate), and bio-based plastics like PLA. PC was once popular for making reusable water bottles, sports canteens, and older baby bottles due to its clarity and durability. However, PC contains bisphenol A (BPA), a chemical of significant concern. Studies suggest BPA may leach when heated or in contact with certain contents, potentially disrupting hormonal balance. Due to these risks, many countries have banned BPA in baby products. Today, many “07” items use safer alternatives such as Tritan. To use such products safely: avoid heating, limit sun exposure, discard if worn or damaged, and choose items labeled “BPA-Free.”
- Conclusion and Action-Oriented Recommendations
Cultivating environmental awareness and making informed choices are essential in today’s plastic-reliant world. Here are practical steps you can take:
Learn to Identify and Use Plastics Safely: Make it a habit to check recycling symbols on plastic items. Understand what each number means, and follow usage guidelines—especially avoiding PET (01) and PS (06) for hot liquids or unsuitable contents.
Dispose Responsibly and Support Recycling: Follow local recycling instructions at all times. This way, plastic waste can be sorted and handled appropriately. Rinse bottles and containers before disposal to improve recyclability.
Prioritize Health and Replace When Needed: Even plastic items made from safer materials degrade over time. Check your plastic items for scratches, cloudiness, warping or wear. Replace them if you find any damage. This rule applies most of all to regularly used items like water bottles and food containers.
Change begins with small, conscious decisions. By understanding plastic codes and adopting these practices, we can reduce waste, safeguard our health, and contribute to a more sustainable lifestyle.