Cling wrap, or plastic food film, is used in modern kitchens to seal containers and preserve food. Its ability to stretch and adhere to itself and smooth surfaces without adhesive makes it an effective preservation tool. The film’s composition varies by manufacturer and region, involving a blend of base polymers and chemical additives. Understanding these materials clarifies its utility and addresses concerns about safety and environmental impact.
The Primary Polymers Used in Modern Cling Film
Cling film’s base material is a long-chain polymer. Historically, Polyvinyl Chloride (PVC) was the industry standard. PVC film is valued for its clarity, strength, and natural “cling.” It also provides a good oxygen barrier, making it a choice for wrapping fresh meats and cheeses commercially.
Due to environmental and health concerns, there has been a shift away from PVC for household use, especially in the U.S. and Europe. Most consumer-grade products now utilize Polyethylene (PE), specifically Low-Density Polyethylene (LDPE) or Linear Low-Density Polyethylene (LLDPE). PE films have a favorable safety profile and are generally freezer and microwave friendly.
PE films naturally possess less adhesion than PVC, requiring different manufacturing techniques for tackiness. A third, less common polymer is Polyvinylidene Chloride (PVDC). PVDC is an excellent barrier against oxygen and moisture, offering long-term food preservation, but it is more expensive and presents disposal challenges.
Plasticizers and Additives That Provide Cling
Base polymers alone lack the necessary cling and flexibility for food wrapping. In PVC films, manufacturers incorporate plasticizers, which are mixed into the rigid polymer chains to soften the material and allow it to stretch. These plasticizers are often esters of adipic acid, such as di(2-ethylhexyl) adipate (DEHA), or citrates.
The amount of plasticizer used impacts the film’s performance and adherence. Older PVC formulations sometimes used phthalates, such as DEHP, but these have been restricted or banned in food-grade wrapping due to health concerns. Newer, food-safe plasticizers ensure the film remains pliable for effective sealing.
PE films typically do not use traditional plasticizers because the PE polymer is more flexible than PVC. The cling in PE wraps is achieved by mixing in specific chemical “cling agents,” often glycerol esters like glycerol mono-oleate. These agents enhance the film’s ability to stick to itself and other surfaces, largely through electrostatic attraction.
Material Safety and Usage Guidelines
The primary safety concern relates to the migration, or leaching, of chemical components into food, especially when exposed to heat or fatty substances. Plasticizers in PVC film are fat-soluble and transfer more readily into high-fat foods like cheese, meats, or oily leftovers. This migration is accelerated when food is stored for extended periods or heated.
Regulatory bodies, including the U.S. Food and Drug Administration (FDA), establish strict standards for food-grade plastic wraps. These standards define the maximum allowable migration of substances from the film into food, with limits set below toxic levels. Consumers should look for products labeled “food-grade” or “microwave-safe” to ensure compliance.
When using cling film in a microwave, follow safe usage guidelines. The danger is not the microwave energy, but the heat generated by the food, which can cause the film to soften or melt. High-fat or high-sugar foods heat faster and can exceed the film’s tolerance, increasing chemical migration. Avoid allowing the film to directly touch the food; use it instead as a loose cover or “tent.” Leaving a small corner unsealed or poking a hole allows steam to vent, preventing excessive heat buildup.
Recyclability and Disposal Challenges
The thin, flexible nature of cling wrap challenges standard municipal recycling systems. The film tends to tangle in sorting machinery at material recovery facilities, causing operational shutdowns. Therefore, most curbside recycling programs instruct residents to place cling film in general waste.
Contamination complicates the issue, as cling wrap is often soiled with food residue, oils, or moisture. Even if the film is made from a recyclable polymer like LDPE, contamination can compromise the entire batch. Cling film made from PVC or PVDC is generally not recyclable due to its chemistry and separation difficulty.
Some specialized collection points, often at grocery stores, accept clean, dry plastic film for recycling, but this is not a universal solution. When disposed of in general waste, cling film contributes to landfill volume and is extremely slow to break down. As it degrades, the material fragments into microplastics, posing a long-term pollution threat.