Daily necessities like food and household items are indispensable in people’s daily lives. As the pace of life continues to accelerate, various packaged foods and daily necessities have filled supermarkets and shopping malls, making it convenient for people to purchase, store, and use these items. Packaging materials play a crucial role in this convenience. With the continuous development of the packaging industry, automatic packaging production lines are being increasingly used in the production of food and daily necessities. As the speed and automation of packaging machines continue to increase, quality issues have also become prominent. Problems such as film breakage, slippage, production line interruptions, and package leaks are becoming more frequent, causing significant losses to many flexible packaging material manufacturers and printing companies. The main reason lies in the inability to control the friction and heat sealing properties of the automatic packaging films.
Currently, the automatic packaging films on the market have the following main shortcomings:
- The outer layer of the packaging film has a low coefficient of friction (COF), while the inner layer has a high COF, causing slippage during the film run on the packaging line.
- The packaging film performs well at low temperatures but experiences issues at higher temperatures during the automatic packaging process.
- The low COF of the inner layer prevents proper positioning of the contents within the packaging film, leading to sealing failures when the heat seal strip presses on the contents.
- The packaging film performs well at low speeds but experiences poor heat sealing and leakage issues as the packaging line speed increases.
Do you understand the COF of automatic packaging film? Common anti-blocking and slip agents and challenges
The COF measures the sliding characteristics of packaging materials. The film’s surface smoothness and appropriate COF are critical for the film packaging process, with different packaging material products having varying COF requirements. In actual packaging processes, friction can act as both a driving and a resisting force, necessitating effective control of the COF within an appropriate range. Generally, automatic packaging films require a relatively low COF for the inner layer and a moderate COF for the outer layer. If the inner layer COF is too low, it may cause instability and misalignment during bag forming. Conversely, if the outer layer COF is too high, it can cause excessive resistance during packaging, leading to material deformation, while too low COF can result in slippage, causing tracking and cutting inaccuracies.
The COF of composite films is influenced by the content of anti-blocking and slip agents in the inner layer, as well as the film’s stiffness and smoothness. Currently, the slip agents used in inner layers are typically fatty acid amide compounds (such as primary amides, secondary amides, and bisamides). These materials are not fully soluble in polymers and tend to migrate to the film surface, reducing surface friction. However, the migration of amide slip agents in polymer films is affected by various factors, including slip agent concentration, film thickness, resin type, winding tension, storage environment, downstream processing, usage conditions, and other additives, making it difficult to ensure stable COF. Moreover, as more polymers are processed at higher temperatures, the thermal oxidative stability of slip agents becomes increasingly important. Oxidative degradation can lead to a loss of slip agent performance, discoloration, and odor.
The most common slip agents used in polyolefins are long-chain fatty acid amides, from oleamide to erucamide. The effectiveness of slip agents is due to their ability to precipitate on the film surface after extrusion. Different slip agents exhibit different rates of surface precipitation and COF reduction. As amide slip agents are low-molecular-weight migratory slip agents, their migration within the film is influenced by various factors, resulting in unstable COF. In solventless lamination processes, excessive amide slip agents in the film can cause heat sealing performance issues, commonly referred to as “blocking.” The mechanism involves the migration of free isocyanate monomers in the adhesive to the film surface, reacting with the amide to form urea. Due to the high melting point of urea, this results in reduced heat sealing performance of the laminated film.
Novel non-migratory super slip & Anti-blocking agent
To address these issues, SILIKE has launched Non-precipitating Super-slip & Anti-blocking Masterbatch Additive – part of the SILIMER series. These modified polysiloxane products contain active organic functional groups. Their molecules include both polysiloxane chain segments and long carbon chains with active groups. The long carbon chains of active functional groups can physically or chemically bond with the base resin, anchoring the molecules and achieving easy migration without precipitation. The polysiloxane chain segments on the surface provide a smoothing effect.
Specifically, SILIMER 5065HB is designed for CPP films, and SILIMER 5064MB1 is suitable for PE-blown films and composite packaging bags. The advantages of these products include:
- SILIMER 5065HB and SILIMER 5064MB1 offer excellent anti-blocking and smoothness, resulting in a lower COF.
- SILIMER 5065HB and SILIMER 5064MB1 provide stable and permanent slip performance over time and under high-temperature conditions, without affecting printing, heat sealing, transmittance, or haze.
- SILIMER 5065HB and SILIMER 5064MB1 eliminate white powder precipitation, ensuring the integrity and aesthetics of the packaging.
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SILIKE’s SILIMER non-Blooming slip agent series provide an excellent solution for controlling the COF of automatic packaging films, from Cast Polypropylene Films, PE-blown films to Various multiple composite functional films. By addressing the migration issues of traditional slip agents and significantly improving the performance and appearance of packaging films, SILIKE offers a reliable choice for flexible packaging material manufacturers and printing companies.
Contact us Tel: +86-28-83625089 or via email: amy.wang@silike.cn
website: www.siliketech.com to learn more.
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Company Name: Chengdu Silike Technology Co.,Ltd.
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Country: China
Website: https://www.siliketech.com/
