In the entire process of production, transportation, and use of film products, the storage stage is often overlooked. Although films may seem "shelf-stable," improper storage can not only shorten their shelf life but also lead to performance degradation—such as reduced tensile strength and increased susceptibility to breakage—ultimately compromising their packaging and protective effectiveness. Different types of films, due to variations in materials and manufacturing processes, have vastly different requirements for storage temperature and humidity. This article will detail the specific storage conditions tailored to common film types, as well as the precise impact of uncontrolled temperature and humidity on their shelf life.

I. Packaging Film Products: Moisture-proof, Temperature-Controlled, and Anti-Material Aging

Packaging films (such as stretch film, cling film, and heat-shrink film) are typically made from core materials like PE, PVC, and PP, which are sensitive to temperature and humidity and prone to issues such as "hard embrittlement" and "adhesion."

1. Stretch film (primarily made of PE material)

• Suitable Storage Conditions 

1. Temperature: 15°C–25°C (room temperature, avoid extreme temperature fluctuations)
2. Humidity: 40%–60% (moderate to low humidity; prevent moisture absorption into the film roll)
3. Additional requirements: Stack no more than 3 layers to prevent deformation of the bottom layer; keep away from sharp objects to avoid scratches.

• The Impact of Temperature and Humidity on Shelf Life 

1. Temperature > 30°C: PE softens, leading to interlayer adhesion—resulting in materials that "can't be torn apart" or "break into fragments"; accelerated aging reduces the shelf life from 12 months to just 6–8 months, while tensile strength drops by 20%–30%.
2. Temperature <5°C: PE becomes hard and brittle, easily breaking under tension, leading to an automation equipment downtime frequency that increases by 3 to 5 times; when transitioning from low to room temperature, condensation is likely to occur, causing slippage during use.
3. Humidity > 70%: Outer packaging absorbs moisture and becomes soft, while the film rolls collapse and deform. High humidity accelerates microbial growth, potentially causing mold spots on food-grade films.

2. Cling film (made of PE or PVC materials)

• Suitable Storage Conditions 

1. Temperature: 10℃–20℃ (Avoid high temperatures to prevent plasticizer migration)
2. Humidity: 35%–50% (low humidity, prevents membrane adhesion)
3. Additional requirements: Store in a sealed container, avoiding contact with air; keep away from oils and solvents to prevent swelling.

• The Impact of Temperature and Humidity on Shelf Life 

1. When the temperature exceeds 25°C: PVC cling film may experience plasticizer migration, causing the film to become sticky and lose its transparency, potentially contaminating food. Meanwhile, PE cling film softens, leading to irregular stretching and tearing, which reduces its shelf life from 6 months to just 3 to 4 months.
2. Humidity > 60%: After packaging is damaged, the film layer absorbs moisture, causing adhesion and clumping that makes it difficult to tear apart. Prolonged exposure to high humidity can lead to mold growth along the film edges, compromising food-contact safety.

3. Heat-shrink film (made of PE and POF materials)

• Suitable Storage Conditions 

1. Temperature: 18°C–22°C (constant temperature, ensuring stable shrinkage rate)
2. Humidity: 45%–55% (balanced humidity, ensuring stable performance and preventing shrinkage)
3. Additional requirements: Store away from light (POF protects against UV-induced aging); stack film rolls upright to prevent deformation caused by pressure between layers.

• The Impact of Temperature and Humidity on Shelf Life 

1. Large temperature fluctuations (e.g., 28℃/10℃): Material stress becomes unstable, causing shrinkage variations to widen from ±3% to ±8%, resulting in wrinkling at the package edges and corners, as well as sagging in the middle. As a result, the shelf life is shortened from 18 months to just 10–12 months.
2. Humidity <35%: POF film becomes brittle due to dehydration and is prone to shrinkage and breakage; PE film experiences increased static electricity, attracting dust that spoils its appearance.

II. Electronic Protection Film Products: Temperature-Controlled, Antistatic, and Preventing Performance Degradation

Electronic protective films (such as tempered glass films and screen protectors) typically feature a composite structure of "base material + adhesive layer + release liner." The adhesive layer is sensitive to temperature and humidity, making it prone to "debonding" and "bubble formation."

1. Smartphone Tempered Glass Film (Glass Substrate + Silicone Layer)

• Suitable Storage Conditions 

1. Temperature: 20°C–24°C (constant temperature, prevents aging of the adhesive layer)
2. Humidity: 40%–50% (moderate humidity, preventing moisture loss or absorption in the adhesive layer)
3. Additional requirements: Individually boxed for scratch protection; keep away from magnetic fields to prevent "magnetic marks."

• The Impact of Temperature and Humidity on Shelf Life 

1. When the temperature exceeds 28°C: The silicone layer ages and loses its adhesive properties, making it easy for the patch to detach. Additionally, delamination occurs between the glass and the adhesive layer, reducing the shelf life from 24 months to just 12–15 months.
2. Humidity > 60%: The adhesive layer absorbs moisture, causing bubbles after application; the release film develops mold, and residual mold spots on the adhesive layer render it unusable.

2. Screen protector film (PET substrate + acrylic adhesive layer)

• Suitable Storage Conditions 

1. Temperature: 15℃–25℃ (room temperature, prevents adhesive layer migration)
2. Humidity: 38%–52% (stable humidity, preventing fluctuations in adhesive layer performance)
3. Additional requirements: Packaged in antistatic sealing bags; ensure environmental grounding to prevent coating breakdown.

• The Impact of Temperature and Humidity on Shelf Life 

1. Temperature <10°C: The acrylic adhesive layer becomes rigid and loses its fluidity, causing edges to lift and curl. When transitioning from low to normal temperatures, "white fog" is likely to form, compromising transparency.
2. Humidity <35%: The PET substrate becomes more statically charged, attracting dust and causing "black spots" in the adhesion area. Additionally, the anti-blue light coating cracks and loses effectiveness, reducing the shelf life from 18 months to just 8–10 months.

III. Building and Automotive Membrane Products: Moisture-Proof, Sun-Protection, and Anti-Structural Damage

Building films (such as insulation films and shatter-resistant films) and automotive films (including window films, etc.) feature a "multi-layered functional structure," are large in area and thick in thickness, and thus require protection against "deformation" and "aging."

1. Architectural Insulation Film (PET Substrate + Metal Insulation Layer + Adhesive Layer)

• Suitable Storage Conditions 

1. Temperature: 18°C–23°C (constant temperature, prevents oxidation of the metal layer)
2. Humidity: 45%–60% (moderate to high humidity, preventing substrate embrittlement)
3. Additional requirements: Store flat to prevent stretching or deformation; keep away from corrosive gases to avoid discoloration of the metal layer.

• The Impact of Temperature and Humidity on Shelf Life 

1. Temperature > 28°C: The metal layer oxidizes, reducing thermal insulation performance by 30%–40%; the adhesive layer ages and delaminates, shortening the shelf life from 36 months to 18–24 months.
2. Humidity < 40%: The PET substrate loses moisture, causing lateral shrinkage and increasing dimensional deviation from ±2mm to ±5mm, resulting in gaps at the edges and corners during application.

2. Automotive window film (PET substrate + dye layer + adhesive layer)

• Suitable Storage Conditions 

1. Temperature: 15°C–25°C (room temperature, prevents fading of the dye layer)
2. Humidity: 40%–55% (balanced humidity, prevents adhesive layer failure)
3. Additional requirements: Store away from light to prevent fading; secure both ends of the film roll with foam padding to protect against collisions.

• The Impact of Temperature and Humidity on Shelf Life 

1. Direct sunlight exposure: The pigment in the dye layer breaks down, leading to uneven color; meanwhile, the adhesive layer accelerates aging, causing edges to warp within 1 to 2 months of installation.
2. Humidity > 65%: The adhesive layer undergoes hydrolysis, losing its tackiness and making installation prone to detachment; the outer packaging becomes soft, and the film rolls develop wavy, difficult-to-smooth wrinkles during application.

IV. General Storage Recommendations: 3 Key Actions to Extend Shelf Life

Regardless of the type of membrane, storage must involve "environmental control + protection." The following recommendations can be implemented directly:

1. Store by region to avoid mixed-placement interference

• Divide the areas by membrane type (such as packaging film area, electronic film area, etc.), with each zone independently controlled for temperature and humidity, equipped with thermohygrometers (accuracy of ±1℃, ±5% RH).
• Do not store together with solvents, oils, or corrosive substances to prevent material swelling and aging.

2. Stack and arrange carefully to prevent physical damage

• Small roll film (cling film, tempered glass film): Stack no more than 5 layers, with the bottom pallet raised by at least 10 cm to prevent moisture.
• Large roll film (stretch film, construction film): Store vertically using a support for secure placement; when stacked horizontally, limit to no more than 2 layers to prevent deformation from pressure on the bottom layer.

3. First-in, first-out; reduce long-term storage

• Establish an inventory ledger, marking production dates and shelf lives, and prioritize using products that were stored earliest (especially those with shorter shelf lives).
• For long-term storage (over 6 months), randomly inspect 1 to 2 rolls each month, removing any products that are stuck together, aged, or deformed.

Conclusion: Storage is the final line of defense for preserving the "performance" of membrane materials.

The shelf life of film products isn’t a “fixed value”: For the same wrapping film, it’s suitable for storage in ideal conditions for 12 months, but only 6 months under high-temperature and high-humidity environments. Meanwhile, the same tempered glass film can be stored for up to 2 years when kept in a constant-temperature, sealed environment, yet its shelf life drops to just 10 months in low-temperature, dry conditions.

For businesses, controlling storage temperature and humidity can extend shelf life, reduce waste, and ensure stable performance. For individuals, properly storing household films—such as keeping cling film sealed in a cool, shaded area—can prevent them from becoming unusable after only half of their intended use. Paying attention to storage details is the key to maximizing the "practical value" of film products.