Summer high-temperature winding challenges: core heating, adhesive layer sticking, glue migration, and end-face slippage.

Preface 

With the onset of sustained high-temperature weather in summer, film-processing plants are commonly facing batch‑level defects in the winding process. Workshop temperatures have exceeded 32℃ The finished‑goods warehouse is stuffy and poorly ventilated, and after the parent rolls come off the machine, heat remains trapped inside. Even when production parameters and equipment settings are identical to those used in winter, malfunctions still occur frequently. Core heating within the film roll, interlayer adhesion, adhesive layer migration, and slippage at the end faces leading to delamination. Four major malfunctions. 

These types of issues are concentrated in protective films, CPP Cast film, flexible packaging composite film, TPU For product categories such as functional films, the consequences range from minor issues like slitting rework and cosmetic defects to severe outcomes like entire rolls being scrapped and customer returns requiring compensation. Many manufacturers mistakenly attribute these problems to raw material quality, when in fact high temperatures alter the film substrate, the adhesive layer, and the winding‑process mechanics. Drawing on practical production experience during the summer months, this article dissects the root causes of four major winding‑related failures and presents actionable solutions for process optimization, equipment upgrades, and warehouse management—helping film producers swiftly address the challenges of high‑temperature winding and reduce production losses. 

I. Four Common High-Frequency Faults and Their Root Causes in Summer Heat-Related Winding Operations 

In high-temperature environments, the film substrate softens, the adhesive layer becomes more fluid, and air‑based heat dissipation efficiency declines. Combined with minor variations in winding tension, taper, and workshop conditions, these factors can lead to batch‑level defects, with each of the four major failure modes having a distinct root cause. 

1. The core of the film roll overheats, and heat builds up inside, causing the roll to become闷 (stuffy/overheated). 

In summer, ambient temperatures are high, significantly increasing frictional heat generation during high-speed film winding. Moreover, the film roll adopts a multi-layer, tightly stacked structure, which impedes rapid heat dissipation, causing substantial heat to accumulate in the inner layers of the roll. At the same time, the cooling system in the high-temperature workshop is operating beyond its capacity, resulting in elevated inlet temperatures; after the parent roll exits the machine, its internal temperature continues to rise, leading to… “ Dull roll ” Phenomenon. This latent accumulated heat does not manifest immediately; it typically becomes apparent only after the product is stored in inventory. 24 After a few hours, issues such as soft curling, deformation, and localized bulging gradually emerge. 

2. Interlayer adhesion, localized adhesion 

High temperatures will lower the softening point of the film, PE 、 CPP 、 TPU Once the substrate is heated, its toughness increases while its hardness decreases, leading to a substantial improvement in interlayer adhesion. This effect is particularly pronounced with adhesive‑backed protective films: at elevated temperatures, the adhesive layer’s viscosity rises momentarily and its flowability enhances, so even a slight increase in winding tension can result in excessively tight interlayer bonding. This progression may start with mild adhesion and gradually escalate to localized, sheet‑like sticking across the entire roll, making subsequent unwinding highly prone to tearing the film surface and leaving behind residual adhesive marks. 

3. Adhesive layer migration and yellowing due to adhesive overflow at the end face. 

This is the most challenging issue with summer‑grade protective and coated films. Under high‑temperature conditions, the molecular activity of acrylic adhesives and silicone coatings increases dramatically, causing the originally stable adhesive layer to gradually migrate outward and penetrate the substrate. When winding tension is excessive, the compressive effect accelerates the outward flow of the adhesive toward the film roll’s end faces, resulting in sticky edges, adhesive overflow, and yellowing or blackening. These defects not only compromise the visual appearance but can also lead to residual adhesive and contamination during downstream die‑cutting and lamination processes, ultimately resulting in outright rejection. 

4. End-face slippage, delamination, and tower-shaped curling 

High temperatures cause changes in the film’s surface smoothness and coefficient of friction, while the core experiences slight thermal deformation and unstable torque transmission at the spindle. During winding, an imbalance in friction between film layers or between the film and the core leads to lateral slippage, ultimately resulting in uneven end faces, layer misalignment, and tower‑shaped rolls. In many factories, the defect rate during high‑speed rewinding spikes in summer—primarily due to high‑temperature slippage, rather than equipment‑precision issues. 

II. Targeted Solutions: Implementation and Optimization Plan for High-Temperature Winding Faults 

To thoroughly resolve the issue of roll-up during the summer, it is not sufficient to adjust a single parameter; instead, one must consider… Temperature control, tension taper, winding process, and warehouse heat dissipation Simultaneous optimization across four dimensions to adapt to high-temperature production environments. 

1. Environmental Temperature Control: Safeguarding the Production Baseline Threshold 

In the summer, the film production and rewinding workshops must strictly control temperature and humidity; the key standard is temperature. ≤28℃ , humidity 40%–60% During periods of high temperature, prioritize activating the workshop’s air-conditioning and ventilation systems, along with the chiller units, to lower the film‑entry temperature and prevent the film from being wound up hot. Adhesive‑backed protective films and precision optical films must be processed under separate temperature controls to eliminate high‑temperature operations. In workshops lacking adequate ventilation, avoid large‑scale production during the peak midday heat to minimize the risk of heat buildup. 

2. Tension taper adjustment: eliminates high-temperature extrusion-induced layer adhesion. 

During the summer, continuous constant-tension winding is strictly prohibited! At high temperatures, the film becomes softer and more prone to deformation, so it is necessary to use Variable Taper Tension Mode : The smaller the roll diameter, the lower the tension in the inner layer; as the roll diameter increases, the gradient‑adjusted tension is fine‑tuned, resulting in a reduction of overall tension compared to winter conditions. 10%–15% The inner layer features just the right amount of elasticity, preventing adhesive migration and sticking caused by high‑temperature compression while also eliminating slippage and delamination at the end faces, thereby addressing the root cause of uneven tension between the inner and outer layers. 

3. Process Optimization: Standardization of Cooling, Unmolding, and Shaping 

The high-speed production line must activate the cooling rollers and air-cooling system to pre‑cool the film, preventing direct winding of hot film. After the parent roll is removed from the machine, it must not be stacked immediately; instead, it should be laid flat in a single layer to allow for ventilation and heat dissipation. 4–8 After several hours, once the internal heat of the film roll has fully dissipated and the adhesive layer has cooled and set, proceed with stacking, slitting, or storage. For rolls with slight adhesive overflow at the ends, gently spray a dedicated release agent on the end faces to prevent adhesive adhesion and contamination. 

4. Core–equipment compatibility: Addressing slippage and deformation. 

Use caution with ordinary products in summer heat. HDPE The core can undergo slight deformation under prolonged high temperatures, leading to shaft‑head slippage and eccentric winding. For high‑end films and large‑diameter parent rolls, this option should be prioritized. ABS High-precision core reels and aluminum alloy core reels offer dimensional stability and resist high‑temperature deformation. In addition, the take‑up spindles and tension sensors are inspected daily, with zero‑point drift promptly calibrated to prevent layer misalignment and tower‑shaped winding caused by uneven torque. 

III. Special Precautions for Summer Rewinding of Different Films 

1. Protective film (silicone) / Acrylic adhesive) 

High temperatures are most likely to cause adhesive overflow and layer adhesion; therefore, low tension and a slow winding taper are required to shorten the inventory cycle. Long-term storage in high‑temperature warehouses is prohibited, and priority should be given to: “ Produce on the same day, sort and allocate on the same day, store at low temperature. ”。

2. CPP Cast film, flexible packaging composite film 

The substrate softens and deforms easily when heated; therefore, it is crucial to optimize the cooling system’s efficiency to prevent internal heat buildup caused by inadequate cooling, thereby avoiding wrinkling and excessive interlayer adhesion after storage. 

3. TPU , functional waterproof membrane 

High-temperature elasticity is significantly improved; excessive winding tension can lead to permanent deformation, so the overall winding pressure should be reduced and a slight interlayer gap should be maintained to ensure adequate ventilation and heat dissipation. 

4. Ultra-thin optical film, release film 

It exhibits extremely high sensitivity to temperature and tension, requiring production in a temperature‑controlled environment. Throughout the process, it must be wound under low tension at a consistent speed to prevent issues such as high‑temperature slippage, creasing, and adhesive layer migration. 

IV. Common Misconceptions About High-Frequency Rolling Up in Summer, 90% Factories are all stumbling into pitfalls. 

Misconception 1 : Increase tension when slipping occurs at high temperatures. 

Wrong! Increasing tension will only exacerbate adhesive-layer extrusion and migration, as well as interlayer adhesion. While the end face may appear neat in the short term, over time the entire roll can become stuck together, leading to breakage during unwinding and even more severe losses. 

Misconception 2 : Direct stacking and storage upon removal from the parent roll machine 

Wrong! The high-temperature parent roll accumulates severe internal heat, and once stacked, the heat cannot dissipate at all. 24 Within hours, soft curling, deformation, and glue overflow occur, which are the primary causes of mass scrap during the summer. 

Misconception 3 : A single set of winding parameters for both winter and summer use 

Wrong! Film hardness, adhesive layer flowability, and the coefficient of friction all vary significantly with temperature; parameters must be adjusted differently for winter and summer conditions. Failure to do so will inevitably lead to batch‑level defects. 

Conclusion 

Summer high-temperature winding failures are never due to a single equipment or material issue; rather, they stem from systemic problems caused by mismatches across multiple dimensions—temperature, tension, process parameters, and storage conditions. The four major pain points—core heat buildup, interlayer adhesion, adhesive migration, and end-face slippage—may seem like minor defects, but they can significantly drive up scrap and rework rates, jeopardizing on-time order delivery and damaging customer reputation. 

To ensure smooth operations during the summer, a film‑manufacturing plant need not resort to indiscriminate raw‑material substitutions or costly equipment upgrades. By precisely adjusting temperature and humidity setpoints, optimizing tension and taper settings, standardizing cooling and shaping processes, and selecting dedicated core designs, it can significantly reduce the incidence of winding defects in hot weather. Mastering the finer points of high‑temperature production and implementing comprehensive temperature control and process‑alignment across the entire line is the most direct and effective approach to cutting costs and boosting efficiency during the summer months.