One of the current situation and development of th

One of the contributions of the plastic flexible packaging industry to the market economy is to promote the sales of goods through the decoration design and production of product packaging. Relevant experts have demonstrated that 53% of the external information received by human senses comes from visual perception, 11% from auditory reception, 35% from olfactory perception, and another 1% from taste perception. It can be seen that the reception of external information by the visual system is the most commonly used and the most frequent sense. The design and production of color printing plastic flexible packaging can just completely approach people's visual field. What is the value of our plastic flexible packaging industry, especially the packaging produced by various enterprises, in product promotion? It can be calculated by the formula provided by the International Statistical Association. Good packaging can improve the benefit of sales by 15 ~ 18%, that is:

15% (18%) × Current year sales volume × Sales profit × Sales volume extending for three years

this is the value of packaging

according to the information provided by the American Design Association, the input-output ratio of good image design and advertising in social and commercial functions is 1:227 US dollars

another major contribution of the plastic flexible packaging industry to the market economy lies in the formation of a kind of preventive measures for the phenomenon of hydraulic jaw clamping on the screen display hydraulic universal testing machine, digital display hydraulic universal testing machine, etc. through technological innovation, the industry dominated by color printing plastic flexible packaging and related industries supporting it have created a large number of jobs, promoted economic development, and become a new economic growth point

color printing plastic flexible packaging developed rapidly in China in the 1990s, which benefited not only from China's reform and opening-up policy, but also from the development of science and technology and the development of polymer chemical industry. Color printing plastic flexible packaging introduces technology, equipment and materials, and gradually realizes localization and self supply. The output of plastic packaging materials increased from 380000 tons in 1982 to 2.43 million tons in 1996, with an average annual growth rate of 14.17%. The proportion of plastic packaging industry in the total industrial output value of packaging industry has reached 26.49%, which is 2.5 times that of metal packaging industry and 4.16 times that of glass packaging industry. The proportion of total assets is 24.4% of the packaging industry, 2.2 times of the metal packaging industry and 3.74 times of the glass packaging industry. In 1999, plastic packaging products reached 3.35 million tons, 1.38 times that of 1996. Since 1996, the average annual growth rate has been 34.47%

the development of color printing plastic flexible packaging industry has driven the development of BOPP, PE, pet, CPP, vacuum aluminizing, pearlescent film and other plastic film production enterprises. In 1998, China has more than 70 film production lines, which is associated with the development of China's petrochemical industry and product innovation

The development of color printing plastic flexible packaging industry also drives the development of gravure printing technology and flexographic printing technology. In 1996, flexographic printing accounted for more than 70% of packaging printing in the United States. It grows at a rate of 15% every year, and 60% of Italy's packaging and printing adopts flexible printing. At present, the proportion of flexible printing and gravure printing in packaging printing is: region America Europe Asia

flexible printing 50% 40% 8% gravure printing 50% 60% 92%

this provides a great space for the application and promotion of flexible printing technology. The development of the plastic flexible packaging industry of caiju statistical printing has driven the development of printing and packaging machinery and auxiliary materials, such as multi-color gravure printing machine and computer automatic plate alignment technology, dry compounding machine, slitting machine and photoelectric deviation correction technology, various forms of bag making machine, flexible printing machine and auxiliary materials. It has formed a full set of plastic flexible packaging machinery production bases in Dalian, Tangshan, Tianjin, Shanghai, Wuxi, Shantou, Wenzhou, Ruian, Guangzhou, etc., and also led to the production of ink. It has formed Tianjin Dongyang, Shanghai Kele sikebai, Kangzhou HANGHUA, Taiyuan Gaoshi Laurie, Guangdong Shunde Jinlong, Shenzhen shenri, Zhejiang New Oriental, Shanghai DIC, Fujian Fuzhou, Shanghai Silian, Zhejiang yongzai, Guangdong Jiangmen Dongyang, Gansu Gangu Guangdong Meining, and other ink manufacturers with an annual output of T. It has driven the development of the electric engraving plate making industry in Yuncheng, Shanxi Province, and the new ceramic roller laser engraving plate making industry represented by Shanghai in recent years

The development of color printing plastic flexible packaging industry not only creates many employment opportunities for itself, but also provides new business opportunities for packaging design, material supply, raw material and product transportation and other industries. It has begun to form an emerging industry dominated by color printing plastic flexible packaging processing. Only Jingtou village, Jingtou Township, Sucheng District, Jiangsu Province, a small village with only 3 poor ridge land per capita and used to think that "this is a kind of golden beans, but it can't make people rich". Due to the development of colored plastic packaging of batteries, the output value was 59million yuan in 1998, the per capita net income of farmers was 3995 yuan, and the products accounted for 80% of the domestic market share. Its tentacles are distributed in the north and south of the river, inside and outside the Great Wall, and even the border between China and Myanmar. Its products are supplied to more than 20 provinces, cities The 130 large and medium-sized battery factories in the autonomous region recently signed an agreement with Changhong Group, the largest color TV production enterprise in China, on the designated production base of color plastic packaging for Changhong alkaline batteries. There are more than 250 farmers engaged in processing industry in the village, several private enterprises have fixed assets of more than one million yuan, more than 100 employees, and the village has more than 150 vehicles and vessels for product transportation. The rise and development of the color printing plastic flexible packaging industry has injected new vitality into old enterprises, increased the scientific and technological content of the original township enterprises, opened up new avenues for the development of sole proprietorship enterprises, and made historic contributions to social stability and economic prosperity in China

although the color printing plastic flexible packaging industry in China started late, its starting point is high. Polymer material engineering closely follows the development of world science and technology. Large film production lines of various materials are the most advanced equipment in the 20th century. Computer technology has been used in the whole process of raw material production, product design, packaging and processing. ISO9000 quality certification system has been established in many factories. ISO14000 international standards for environmental management have begun to be accepted at home. Commodities with color printing plastic flexible packaging as the main body have been traded abroad. The signing of the WTO agreement has provided convenient conditions for China's opening to the outside world. At the same time, it has opened up a new channel for the technical exchange of plastic flexible packaging and product export, and opened up a broader market

II. Introduction to color printing plastic flexible packaging process

color printing plastic flexible packaging process is the synthesis of plastic film color printing process, plastic film composite process and plastic composite bag making process. First of all, after printing colored embossed text in the plastic film, it should be compounded with other materials of different materials (such as PE, CPP, pet, transparent, vacuum aluminized, pearlescent), and then made into plastic composite bags with various sealing styles and different specifications according to the design requirements. The process flow is as follows:

plastic film color printing process → plastic film composite process → plastic composite bag making process

the color printing in plastic film is to attract the attention of consumers through the gorgeous colors of packaging graphic design, so as to have a deep understanding of goods, generate interest and possessiveness, and achieve the purpose of the best first impression. Therefore, in the plastic color printing process, design is the most critical work

plastic film color printing process

conceptual design → electric engraving plate making → prepress processing → color matching → printing sample → color separation gravure printing

plastic film composite process

base film preparation → glue mixing → glue drying → pressure compounding → deviation correction and winding

plastic composite material bag making process

base material preparation → specification setting → temperature setting → pressure setting → speed adjustment → finished product inspection

in plastic flexible packaging Composite material is a material with special function of heating and self-adhesive, which is composed of BOPP printing film and PE, pet, CPP and other lining films with heat sealing performance. The plastic composite bag making process is to explore the characteristics of PE, pet, CPP and other substrates, and use the electric heating device of the bag making machine to produce a phase change that changes the heated part from solid state to viscous flow state. With the help of the power of the knife, the upper and lower films are integrated with each other, and a certain strength can be maintained after cooling

different kinds of plastic films have different heat sealing temperatures. (see the table below)

plastic film heat sealing thermometer

film material heat sealing temperature (℃)

LDPE low density polyethylene 20 ~ 175

HDPE high density polyethylene 135 ~ 155

linear low density polyethylene 175 ~ 180

PP polypropylene (not stretched) 165 ~ 205

OPP polypropylene (stretched) 100 ~ 130

PVC 95 ~ 175

PVDC polyvinylidene chloride 90 ~ 200

PET polyester 150 ~ 190

PC polycarbonate 205 ~ 430

PA polyamide 175 ~ 260

PS polystyrene 120 ~ 165

Pt cellophane 205 ~ 260

Pt cellophane (coated) 95 ~ 260

according to the above parameters, mastering the heat sealing temperature and selecting the best viscous flow state of lining materials are the core technologies of bag making process

increasing the temperature will reduce the viscosity or apparent viscosity of the polymer melt. PE and PP are nonpolar polymers with minimal activation energy and curve rate. The temperature increases greatly, but the apparent viscosity should be reduced by processing a test rod. Heat sealing can only be carried out when the viscous flow temperature is above TT (or TM at the melting point). However, the decomposition temperature Ta of the cloth cannot be exceeded. So as not to cause thermal degradation

plastic composite bag making process, i.e. heat sealing process. There are three major factors in the heat sealing process: heat sealing temperature (T), heat sealing pressure (P), and heat sealing time (T). When the best value of heat sealing temperature (T) is selected, the heat sealing pressure (P) should not be too large and the heat sealing time (T) should not be too long. The best heat sealing temperature has transformed the plastic film from solid state to viscous flow state. The best heat sealing pressure (P) and action time (T) can ensure the fusion and interleaving of the upper and lower films. Too much pressure (P) or too long time (T) will cause macromolecule degradation, which will reduce the sealing strength and degrade the interface sealing

third, the reasons for the bending of plastic color printing trademarks

the printing color of modern printing industry has developed from monochrome to six and eight colors, and the efficiency has developed from multiple processes to one-time molding, integrating printing, cutting, concave convex, bronzing and laser. In the process of mechatronics, a series of new problems will inevitably appear in production. Trademark bending is a quality problem often encountered in the production of one-time molding. Trademark bending not only affects the appearance of the trademark, but also directly damages the user's computer applicability, causing the user to stop using this kind of trademark because of dissatisfaction. How to effectively solve and control trademark bending in production is of great significance to improve product quality and meet user needs

Why does the film bend during printing

it is known from the test that under certain pressure and temperature conditions, the greater the tension, the higher the temperature, and the greater the deformation of the membrane of the thin cut rectangular specimen

in the one-time molding production process of gravure multi-color continuous machine, the film is subject to 20 ~ 35dan tension, 25 ~ 40dan pressure, and the drying temperature is 60 ~ 100 ℃. After many times of printing, drying, stretching, and recovery, it will deform to varying degrees. Moreover, in the printing, due to the application of ink, it will cause local and different stretching, deformation, and recovery on the horizontal amplitude of the film surface, and the positive and external sides, so the trademark appears in the finished product