BOPP is often used for printing, coating, bonding, etc. when applied to food, calendars, albums, adhesive tapes, etc. Since the surface tension value of polypropylene material itself is relatively low, it is only 31 dynes. When applied to the above aspects, the surface tension strength of the film is generally required to be more than 38 dynes. Therefore, in the production of BOPP, it is often necessary to surface-treat the film, improve the surface tension, and improve the adhesion and wetting of the polymer. Sex to meet the requirements of use.
There are two common surface treatment methods: one for corona treatment and the other for flame treatment. The principle of corona treatment is that the film passes between two electrodes with high pressure. The high voltage makes the air between the electrodes ionize, which causes electron flow between the electrodes to form an oxidized polarization group on the surface of the film, which makes the film surface have polarity and is easy to print. Ink adsorption; flame treatment is to use a special burner to burn a certain composition and proportion of gas and air to form an oxidizing flame with a temperature of up to 2100~2800 °C, in order to achieve the purpose of changing the surface properties of the film in an instant, in the actual process The temperature of the flame, the distance between the flame and the film, and the processing time are important factors influencing the treatment effect. In practical applications, since corona treatment is simple and easy, and the treatment effect is good, this method is basically adopted by BOPP equipment manufacturers. The following are some aspects of the testing and control of corona treatment on BOPP processing and the effect on the properties of the film.
1.1 Determination of corona treatment strength of BOPP film
The test method commonly used for the surface tension of BOPP film is the coating method. The principle is that the two liquids of formamide and ethylene glycol ethyl ester are mixed in different proportions to obtain a series of test liquids with different dyne values ​​(see table). a) During the operation, the test solution is applied to the surface of the film, and the dyne value corresponding to the test liquid whose liquid level is broken in 2 seconds indicates the corona treatment strength of the film.
As a three-layer co-extruded tobacco film, the main component of the surface layer is a self-adhesive polypropylene copolymer. Currently, BOPP heat sealing materials commonly used at home and abroad mainly include polypropylene random binary copolymer (ethylene/propylene copolymer). Such as SOWAY KS413, Montel PLZ697, CHISSO XF7511, etc., random terpolymers (propylene / ethylene / butene copolymer) such as Solvay KS309, Sumitomo SP89 E-1, Montel EP3C39F and mixtures (terpolymer and butene Mixtures) As Schulman IS2739, these three heat seal materials have their own characteristics, and they have different effects on the heat seal properties of the smoke film.
Cotton Rayon Fabric,59%Cotton 41%Rayon Fleece Fabric,Cotton Rayon Dyed Check Shirt Fabric,Check Design Rayon Cotton Fabric
Shaoxing DeChuan Textile Co., Ltd. , https://www.dechuantex.com