A Guide to Sorting and Recycling Thin-Film Plastics: Don't Let the "White Treasure" Become an "Environmental Burden"

Preface 

Thin-film plastics, owing to their lightweight nature, flexibility, and excellent barrier properties, are widely used in food packaging, industrial protection, agricultural mulching, and other fields, making them essential materials for both production and daily life. However, discarded thin-film plastics... “ Difficult to collect, difficult to classify, difficult to handle. ” Throwing things away carelessly not only pollutes the environment but also wastes resources. 

Waste film plastic is “ White Treasure ” Separate recycling can simultaneously promote environmental protection and resource circulation. Yet many people remain confused: What types of thin-film plastics are there? How can they be distinguished? What should we pay attention to when sorting and recycling them? And how should businesses go about setting up their recycling systems? This article dissects the core logic from multiple perspectives and provides a practical guide. 

I. Basic Understanding: First, get a grasp of the common types of thin-film plastics and their recycling symbols. 

The core of film plastic sorting and recycling is... “ By material type ” The chemical properties, recycling value, and handling methods of different materials vary significantly. Clearly identifying common types and their corresponding recycling symbols is the foundation for effective sorting. 

(1) Common Film Plastic Materials and Their Characteristics 

• Polyethylene ( PE ) Thin film : The most common, categorized as low density ( LDPE , high-pressure membrane) and high-density ( HDPE Low-pressure film, flexible and resistant to low temperatures, used for shopping bags, cling films, agricultural films, and more; it has high recycling value and can be regenerated into plastic pellets or recycled films. 
• Polypropylene ( PP ) Thin film Transparent and temperature-resistant, used for cookie bags and chip bags. BOPP Base films for adhesive tapes, etc.; after recycling, they can be used to make plastic flower pots, trays, and regenerated fibers. 
• Polyvinyl chloride ( PVC ) Thin film Soft type used for cling film, raincoats, and the like; contains chlorine, difficult to recycle, produces toxic gases when incinerated, and recycling is restricted in some regions. 
• Polyester ( PET ) Thin film High transparency and excellent barrier properties, suitable for high-end food packaging, daily chemical packaging, and more; boasts high recycling value and can be regenerated into bottle flakes and fibers. 
• Polyamide ( PA nylon) film High strength and excellent barrier properties; used for food vacuum packaging and high-temperature cooking bags; low recycling volume, mostly recycled at the industrial level. 

(2) Key Identification: Recycling Symbols and Identification Techniques for Thin-Film Plastics 

Our country uses “ Plastic recycling symbol ” (Digit inside the triangle) 1-7 ) Label the material; common markings for thin-film plastics: 

• Composite film Made of two or more materials combined (e.g., PET/PE ), used for complex packaging; the mixture of materials makes recycling difficult, which is a major pain point in the industry; 
• 1-PET (Polyester): Rarely found in film form; mostly used for bottles. High-end films may include labeling. 
• 6-PS (Polystyrene): Very few are in film form; most are foam plastics. 
• 2-HDPE (High-density polyethylene): Low pressure PE Membranes are common, such as shopping bags and industrial packaging films; 
• Quick identification technique for unlabeled films: 
• 4-LDPE (Low-density polyethylene): High-pressure PE Membranes are common, such as cling film and agricultural film; 
• 5-PP (Polypropylene): PP Membrane core labels, such as food packaging films and adhesive tape base films; 
• 3-PVC (Polyvinyl chloride): PVC Membrane labeling, which should be avoided in conjunction with... PE 、 PP Confusion; 
• 7- Other: Composite film, PA Membranes and other labeled materials are difficult to recycle; 

II. Core Process: End-to-End Decomposition of the Full Chain for Sorted Recycling of Thin-Film Plastics 

Film plastic sorting and recycling is “ Front-end classification - Mid-range collection and transportation - Backend processing regeneration ” Throughout the entire chain, each link directly affects recycling efficiency and value. 

(1) Front-end classification: the most critical foundational step 

• Feel-test: Soft and easy to stretch, no creases. →PE Membrane; somewhat firm, average stretchability →PP Membrane; poor tackiness and elasticity → Be vigilant. PVC Membrane; 
• Combustion Test (Safety Precautions Required): PE/PP It burns without any unusual odor, has a paraffin-like scent, produces a bright flame, and leaves minimal residue. PVC The combustion produces a pungent chlorine odor, the flame is black, and it leaves behind a hard, black residue. PET It has a sour smell when burned, the flame is yellow, and it leaves behind a hard, brittle residue. 
• The core of front-end categorization is “ Separate by material, remove impurities. ” To avoid mixing that could reduce value, specific requirements: 
• Transparency Observation: High Transparency, High Glossiness →PP 、 PET Membrane; generally translucent and glossy →PE Membrane; 
• Application association: Inner layer of food packaging, shopping bags →PE ; Cookie and chip bags →PP ; High-end vacuum packaging → It could be a composite membrane; 

Frontend categorization recommendations for different scenarios: 

• By material breakdown: PE 、 PP 、 PET Store separately, PVC Separate and avoid contamination; 
• Remove impurities: Clean away oil stains, residue, labels, etc.; simply wipe the paper layer off food bags. 
• Separate composite membranes: Collected separately; some enterprises can disassemble them, but the cost is high. 

(2) Mid-range collection and transportation: The key link between the front end and the back end. 

• Compression and packaging: Reduce volume, lower transportation costs; 
• The core of collection and transportation is “ High efficiency and concentration, avoiding secondary pollution. ” , common patterns: 
• Household scenario: Store clean plastic films in dedicated recycling bags and regularly deliver them to the community recycling drop-off point to prevent heavily contaminated films from being mixed in. 
• Supermarket and retail settings: Install film recycling bins, assign dedicated personnel to guide sorting, and regularly clean and package the collected materials. 
• Industrial scenarios: For membrane manufacturers, waste materials are collected separately by material type and directly routed to recycling companies; in food processing plants and similar facilities, impurities are removed first before materials are sorted. 
• Transit precautions: 
• Community Recycling Drop-off Point + Transfer station: Residents deliver items to the community, which are then transferred to the transfer station for secondary sorting and compression before being sent to recycling enterprises. 
• On-site enterprise recycling: Directly partnering with large customers such as supermarkets and factories to reduce intermediate links. 

(3) Backend Processing and Regeneration: The Core Link for Achieving Resource Circulation 

• Online appointment for recycling: Tailored to meet small, scattered, and low-volume needs, the platform offers an appointment-based door-to-door pickup service. 
• The processing techniques for films made of different materials vary significantly. The core objective is to convert them into recycled raw materials or end products. Common processes include: 
• Sealed transportation: Prevent spillage and contamination; 

1. Physical regeneration process (mainstream environmental protection, suitable for) PE 、 PP 、 PET Pure thin film (etc.) 

• Store separately: Divide the car into sections to prevent mixing; 
• Timely transportation: Shorten storage time to prevent moisture buildup and bacterial growth. 

2. Chemical depolymerization process (suitable for complex or heavily contaminated films) 

• Crushing and Washing: After crushing, the material is washed to remove impurities, then dehydrated and dried. 

3. Energy recovery process (suitable for non-renewable films, such as... PVC , contaminated composite membrane) 

• Granulation: After drying, the material is extruded and cut into granules to produce recycled pellets. 
• Recycling processing: Used for producing trash bags, agricultural films, injection-molded parts, and more; 
• Chemical reagents break molecular chains, decompose them into monomers, and then re-polymerize them. 

III. Industry Challenges: Core Issues Facing the Sorted Recycling of Thin-Film Plastics 

Despite the significant value of waste sorting and recycling, the industry still faces numerous pain points that hinder recycling efficiency and the level of resource utilization. 

Advantages: Can handle composite membranes and contaminated membranes, with high regeneration purity; Disadvantages: The process is complex and costly, with only limited applications. 

(1) Front-end classification is difficult and has low accuracy. 

• Incineration for power or heat generation, utilizing calorific value to recover energy; 
• Attention: PVC Incineration requires dedicated flue gas treatment equipment to prevent dioxin formation; this serves as a fail-safe measure. 

(2) The challenge of recycling composite films is particularly prominent. 

• Cognitive deficiency: The public confuses materials, and mixed disposal leads to low recycling purity. 
• High identification threshold: It's difficult to distinguish unlabeled films. PE With PP 、 PVC Confusion affects value;

(3) The recycling system is incomplete and costly. 

• Lack of motivation: Absence of incentive mechanisms leads to low participation enthusiasm. 
• High share: Composite films account for the thin-film market. 30% Above; 
• Difficult to separate: The materials are tightly bonded, resulting in poor physical recyclability. 

(4) Recycled products have low added value. 

• High costs: Chemical depolymerization costs are higher than those of physical recycling. 2-3 Twice; 
• Collection dispersion: large volume, light weight, high collection costs; 

IV. Breakthrough Strategies: How Should Enterprises and Individuals Step Up?

Inefficient transportation: Lack of specialized teams and equipment, prone to secondary contamination; 

Solving these challenges requires coordinated efforts from governments, businesses, and individuals. Here are practical recommendations tailored for membrane companies, packaging companies, and individuals: 

Insufficient production capacity: Small businesses are being phased out, while large enterprises face limited capacity. 

(1) Membrane Companies and Packaging Enterprises: Optimizing at the Source to Support Recycling 

• Low value-added: Most recycled products are low-end items such as garbage bags, yielding thin profits. 
• Unstable performance: Difficult to control the purity of recycled materials, and significant fluctuations in the performance of regenerated particles, which limit high-end applications. 
• Prioritize single materials: Choose them as long as they meet the requirements. PE 、 PP Use single-material compositions and reduce composite films; 

(2) Individuals and End Users: Properly carry out front-end sorting and practice green consumption. 

• Promote biodegradable films: Research and development PBAT/PLA Use biodegradable films to reduce pollution at the source; 
• Improve labeling: Clearly indicate the material (e.g., PE-LDPE 4 ), facilitating classification; 
• Establish a recycling closed loop: Connect with downstream partners to recover waste materials and discarded packaging. 
• Upgrade technology: Develop composite membrane treatment technology and optimize the physical regeneration process. 

(3) Industry Organizations and the Government: Perfecting the System and Strengthening Guidance 

• Learn to distinguish: Master basic techniques and sort items according to their material. 
• Remove impurities: Eliminate oil stains, residues, labels, and the like. 
• Green consumption: Choose simple packaging and reduce composite packaging. 
• Reuse: Reuse shopping bags and other items multiple times before recycling them; 

V. Industry Trends: The Future Direction of Sorted Recycling of Thin-Film Plastics 

With the tightening of environmental policies and advancements in technology, the sorted recycling of thin-film plastics will exhibit three major trends: 

• Establish incentives: subsidies and points redemption to boost motivation; 
• Improve the network: Increase investment in recycling stations and establish a professional transportation team. 
• Strengthen publicity: Promote knowledge about waste sorting; 
• Standardization: Develop recycling and regeneration standards to standardize processes and ensure quality.

Conclusion 

Film plastic sorting and recycling is crucial for the environment and resources. “ Mandatory question ” It requires technological breakthroughs and the refinement of systems, and even more so, the participation of the entire population. 

• Simultaneous adoption of single-material design and biodegradability To “ Single recyclable ” and “ Biodegradable ” Development—reduce difficulty at the source; 
• It’s an inevitable trend for film companies to develop recyclable and biodegradable technologies and establish closed-loop recycling systems. For individuals, properly sorting waste and practicing green consumption are simple yet effective ways to contribute to environmental protection. Only through multi-party collaboration can we ensure that discarded plastic films are effectively managed and recycled. “ Environmental burden ” Change “ White Treasure ” Promote green and high-quality development of the membrane industry. 
• What challenges have you encountered in the sorting and recycling of thin-film plastics? What practical tips do you have? Feel free to share them in the comments! 
• Smart recycling technology Introduction AI Identify and automate sorting to enhance efficiency; develop composite membrane treatment technology to break through bottlenecks. 
• Perfecting the circular system : Formation “ Membrane enterprise - Packaging enterprise - Recycling company - Regenerative enterprise ” Closed-loop system to achieve full lifecycle utilization; upgrading recycled products to higher-end markets and enhancing their added value.