Technology and process of printing BOPP plastic film with water-based ink
Date: Nov 10 2023 From: Star Color
With the increasing awareness of environmental protection, water-based ink printing has become an environmentally friendly and healthy way to replace traditional solvent-based ink printing.Water-based ink printing has the advantages of low VOC emission, no irritating odor, non-combustible and non-explosive, and is widely used in the field of packaging printing.BOPP (biaxially stretched polypropylene) plastic film is a common packaging material, with good mechanical properties, transparency and barrier properties, so it has a wide range of applications in water-based ink printing.This paper will discuss the technology and process of
water-based ink BOPP plastic film.Characteristics of water-based ink and BOPP plastic film
Water-based ink is a kind of printing ink with water as solvent, mainly composed of pigment, binder, auxiliary and other components.Among them, the pigment gives the ink color and hiding power, and the binder provides viscosity and film forming properties.Compared with traditional solvent-based inks, water-based inks have the advantages of low VOC emission, no irritating odor, non-combustible and non-explosive.At the same time, the drying speed of water-based ink is slow, and it needs to be dried by heating or ultraviolet irradiation.
BOPP plastic film is a bidirectional polypropylene film with excellent mechanical properties, transparency and barrier properties.It has the characteristics of high strength, high toughness, high transparency, and has high barrier properties to oxygen, water vapor, etc.Therefore, BOPP plastic film is widely used in food, medicine and other packaging fields.In the process of water-based ink printing, BOPP plastic film needs to go through pre-treatment and post-treatment to ensure printing quality and finished product performance.
Printing process flow
1.Film pretreatment
Prior to water-based ink printing, the BOPP plastic film needs to be pre-treated.The purpose of pretreatment is to improve the surface energy of the film, so that it has better wettability and adhesion, so as to facilitate the adhesion and drying of water-based ink.In general, pretreatment includes corona treatment, chemical treatment and plasma treatment.Corona treatment is a common pretreatment method, which can make the surface of the film obtain polarization charge through the action of high frequency electric field generated by high voltage discharge, so as to improve its surface energy.Chemical treatment is the corrosion of the film surface by chemical etchants to increase its roughness and polarity.Plasma treatment uses plasma jet to activate the surface of the film to improve its wettability and adhesion.
2.Ink selection and allocation
The selection and allocation of water-based ink is very important for printing quality and finished product performance.According to the printing requirements and the characteristics of BOPP plastic film, choose the appropriate water-based ink brand and model.At the same time, according to the actual needs, an appropriate amount of additives can be added to adjust to obtain the best printing effect.For example, an appropriate amount of defoamer, leveling agent, thickener and other additives can be added to improve the printability and stability of the ink.
3.Printing
When printing, it is necessary to choose the appropriate printing equipment, screen plate and printing pressure according to the actual needs.In general, water-based ink printing requires the use of a specialized flexographic press or gravure press.In the printing process, it is necessary to control the printing pressure and speed to ensure that the ink can be evenly transferred to the surface of the BOPP plastic film.At the same time, it is necessary to pay attention to the mesh number and accuracy of the screen plate to obtain a clear printing effect.
4.Desiccation
After printing, it is necessary to dry the water-based ink.The purpose of drying is to completely volatilize the solvent in the ink, and to cure the binder into a film.There are many ways of drying, such as hot air drying, ultraviolet drying，etc.According to the actual needs, choose the appropriate drying method.In the drying process, it is necessary to pay attention to controlling the drying temperature and time to avoid product quality problems caused by insufficient or excessive drying.
5.Aftertreatment
Aftertreatment is the last link of water-based ink printing BOPP plastic film.The purpose of aftertreatment is to carry out quality inspection, cutting, packaging and other operations on the finished product to ensure that the product meets the requirements of the customer.During aftertreatment, care should be taken to avoid contamination or damage to the finished product.At the same time, customized cutting and packaging operations need to be carried out according to customer requirements to ensure that the product meets the actual needs of customers.
Water-based ink printing BOPP plastic film is an environmentally friendly and healthy packaging printing method.High-quality printing products can be obtained through the control and management of film pretreatment, ink selection and allocation, printing, drying and post-processing.With the continuous improvement of environmental awareness and the rapid development of the packaging industry, the application prospect of water-based ink printing BOPP plastic film is broad.
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