The friction coefficient is an indicator for measuring the sliding characteristics of BOPP cigarette film. For the operation of cigarette packaging on the machine, an appropriate friction coefficient is important. The film requires good thermal sliding performance to meet the high-speed (400 packages/train to 600 packages/train) sliding under hot conditions, so that the packaging production line can fully open at full speed without affecting production output. The friction coefficient of the outer surface of the thin film to the metal, especially the thermal friction coefficient under high temperature conditions, must be low. In the process of cigarette packaging, the outer surface of the film slides on metal components such as the lower film channel, forming wheel groove, folding plate, soldering iron, guide rail, etc. As these metal components mostly operate under high temperature conditions below 50 ℃, the friction coefficient of the film will increase with the increase of temperature conditions. After 45 ℃, the friction coefficient of the film increases quickly, so the thermal sliding performance of the film should be more suitable for the actual working conditions of the packaging machine, In general, the thermal sliding friction coefficient at 60 ℃ should be mainly controlled. The friction coefficient between the other side of the film and the cigarette packaging paper should be controlled to be high, forming a differential sliding characteristic between the inner and outer sides of the film, in order to facilitate the good positioning of the cigarette packaging with the film within the forming wheel, improve the folding quality, and achieve a compact packaging effect. Due to the fact that BOPP"s anti slip agents usually have migration properties, they need to be stored for a period of time before they can migrate to the surface of the film and fully exert their effects. That is, the film will only be very smooth after being stored for a period of time.

Antistatic performance and its application

During the cigarette packaging process, the static electricity generated by the film has a negative impact on cutting, conveying, and folding, which can cause malfunctions in the film"s operation on the machine. Antistatic characteristics are one of the basic conditions to ensure the smooth operation of the packaging machine. In the process of cigarette packaging, the static electricity of the film is divided into two parts. One part is that the film itself carries static electricity, and the other part is the static electricity generated by friction during the cigarette packaging process. The static electricity of the film itself is relatively easy to control, but it is difficult to control the static electricity generated during the cigarette packaging process. Moreover, the hazards of machine failure are greater. Some cigarette film manufacturers only emphasize that the static electricity value of the film itself is small, while ignoring the static electricity generated during the packaging process. This results in good film detection performance, but machine operation always fails. Antistatic agent is generally added to the middle layer of the film. Therefore, in order to achieve good anti-static effects, the film generally requires a certain storage period. On cigarette factory packaging machines, static electricity can be quickly transferred through metal or static eliminators, and high humidity environments are also conducive to removing static electricity from the film surface. When encountering films with high static electricity or during dry seasons (such as winter), the torch factory can place the films in the packaging workshop in advance. It is ideal for the packaging workshop to adjust humidity, or to wet the workshop floor with water, or to apply a wet towel to the end face of the film roll, which is one of the emergency solutions.

Stiffness and Its Application

When the stiffness of the tobacco film is high, it can achieve high folding quality during the packaging molding process and achieve good heat sealing effect in a short pause time. It is a prerequisite for improving packaging speed and is suitable for high-speed packaging machines with automatic transmission. Different cigarette packaging machines often have different heat sealing conditions, and the same model of cigarette machine produces heat sealing temperatures in different environments. Therefore, a wider heat sealing temperature range can ensure smooth operation on various cigarette packaging machines, and the film has good adaptability. A cigarette film with a narrow range of heat sealing temperature is characterized by a very narrow window for adjusting the heat sealing temperature on a cigarette packaging machine. Setting the heat sealing temperature slightly higher will wrinkle the hot mouth, while setting the heat sealing temperature slightly lower will not seal tightly. Moreover, the heat sealing temperature settings between one roll and another are different, making it difficult to control the heat sealing temperature.

Shrinkage rate and its application

BOPP smoke film is generally divided into ordinary type and heat shrink type smoke film. Ordinary cigarette film generally has relatively small thermal shrinkage performance, with a thermal shrinkage rate generally controlled at (2% -5%), and is generally used for small box soft bags and strip boxes of cigarettes. BOPP heat shrinkable cigarette film has a high heat shrinkage rate, which is generally greater than 7%. After packaging, it can make the cigarette package compact and more uniform, while ensuring that the cigarette package is tight and not loose for a long time. The main feature is excellent body to body packaging effect; Overcoming the problem of looseness and wrinkling of hard box packaging film caused by ordinary cigarette film, heat shrinkable cigarette film has low-temperature heat shrinkage, high transparency, glossiness, and better high-speed packaging performance due to its special processing technology.

Optical Performance and Its Applications

Although the human eye is a tool for evaluating the optical performance of thin films, relying solely on visual control is not enough, as lighting conditions, observer mood, and quantitative control can all have an impact. In order to achieve reliable and achievable quality assurance, objective and measurable parameters are needed to quantify the appearance, and glossiness and haze are two important indicators for quantifying the optical properties of BOPP films. Haze, also known as transparency, measures the percentage of transmitted light that deviates from the direction of the incident light by more than a certain angle. Observing through the thin film, narrow angle scattering is more clear, and the scattering angle can cause a decrease in contrast and haziness. Lower haze can display the clear and bright trademark pattern of the cigarette package. Glossiness is the visual impression obtained when evaluating the surface of a thin film. The more light directly reflected from the surface of the film, the higher the glossiness. A high gloss surface reflects highly concentrated light that can clearly reflect the image, while a low gloss surface reflects light that diffuses in all directions, resulting in a decrease in image quality. The reflected object no longer appears bright but blurs. A higher glossiness will bring a bright visual effect to the cigarette pack.