Post-print surface treatment technology and equipment application analysis

I. Overview

Post-print surface treatment is increasingly important in packaging production. The success or failure of the current market competition depends to a large extent on the packaging of goods, and the quality of the packaging is determined by the quality of the surface treatment of the goods after printing. Therefore, we can say that post-print surface treatment is an important technical measure to improve the packaging quality and strengthen the competitiveness of the commodity market.

Commonly used post-print surface treatment technologies include:

1. Waxed surface. It is mainly used to make packaging can withstand certain moisture and moisture. It used to be used for packaging of fresh meat and agricultural products. This is done on a curtain coater to complete its waxing process.

2. Film. After the film is printed on the packaging product, the film is covered with a plastic film such as acrylic on the surface of the printed matter, and the adhesive is applied by heating and pressing to form a printed matter of paper and plastic.

The coating can be divided into a coated film and a precoated film. That is, the coated film is coated with a binder at the time of operation and then heated and pressed to obtain a finished product. The pre-coating film is pre-coated with a binder on a plastic film, dried and wound, and the surface of the printed product is simply hot pressed. They are completed on instant coated straw and precoated straw.

3. Polishing. Gluing is a colorless and transparent coating (or spray, printing) on ​​the surface of Baolu Printing. After it is leveled, dried, and calendered, it forms a thin and uniform transparent and bright layer on the surface of the printed matter. It is completed by a glazing machine and a calender.

4. Calendered. Calendering is a finishing process after glazing prints, and some direct calendering of high-grade paper products. The calendering of printed products is due to the fact that the glossiness of the glazing material after natural leveling and drying is not ideal, and some fine prints must be calendered. The equipment used is a calender, and many calenders are used with a glossing machine.

5. Other special processing technologies. In recent years, there have been many special post-printing processing technologies for prints, and the development is quicker than that of the people. Common surface coating (also known as spray glue), surface frosting (also known as sanding, that is, in the printing surface grinding point of the sand evenly), embossed embossing, embossing (concave) or simply pressed shape. All of these new post-finishing techniques have been seen more often in high-end packaging for daily use. Especially the exquisite handicrafts and cigarette packaging are common.

Second, technology development and demand

1. Packaging surface treatment technology has become a meeting point for many disciplines and technologies

The packaging and printing technology has shifted from traditional wax coating or laminating to the cross technology that combines the surface features and mechanical characteristics of printed products. The traditional wax coating does not cause any change in the shape of the printed product (before surface modification). Only the wax coating adheres to the surface of the printed product.

2. New materials are constantly being applied to surface finishes

With the improvement of the quality of the printed matter and the requirement of decorative performance, many new materials are applied to the surface finishing process of the printed matter. The new materials that are widely used in the finishing of printed materials are mainly monochromatic inks and various coatings for various properties. With the rapid development of printing science and technology, printing has completely changed the concept of traditional reproduction. Modern printing is a combination of technology and art. It is based on the high-tech information process, and more often uses high-tech methods to make prints more efficient. With a landscaping effect. The material basis of this beautification effect is the special performance ink and less material. For example, photocurable coatings have been used in the finishing of prints to replace traditional waxing and laminating. Another example is that imitation gold, imitation silver inks and paints have been used instead of hot stamping silver. In particular, some high-end tobacco and alcohol, high-end cosmetics and high-end gifts and costumes emphasize the exquisite packaging effect. It is difficult for some traditional decorative inks and coatings to meet requirements, and there are even more stringent requirements for new decorative inks and coatings. It requires high productivity, good printing adaptability, fast drying speed, high gloss, high hiding power, good adhesion, durable wear, safe use, no plugging (holes), easy cleaning, No pollution and other properties. In response to these performances and requirements, UV-curable imitation inks have recently been introduced at home and abroad, and are widely used in high-end tobacco and alcohol, gifts, greeting cards, invitations, calendars, business cards, advertising, art and other high-end packaging boxes (bags). For a long time to come, Xin special inks and coatings are still the focus of research on surface finishing materials.

3. Postpress finishing technology and equipment update speed up

The surface finishing technology of India has developed rapidly. Past surface waxes have been surfaced for a long time, and the surface coating has been partially replaced by surface polishing (glazing solution) not long ago. In the past, general drying of the coating was heated by a far-infrared heater (or ordinary heater), and there were disadvantages such as slow down of the product and easy deformation of the product. Recently, UV-curing coatings and inks have been rapidly promoted, and there is a tendency to gradually replace coated films and infrared heat-curing coatings.

At present, the variety and specification of surface decoration machinery and equipment after packaging and printing in China have been diversified, and the number has reached more than 100 species. In the past, some major models and models were imported. After years of digestion and absorption, most models have been able to design and produce on their own. With the application and promotion of high technology, some old-fashioned equipment and processes have gradually been eliminated. For example, surface waxing equipment and processes are gradually replaced by coating or glazing processes, so the curtain-type wax coating machine is basically in In stagnation, few manufacturers reproduce.

With the diversification of printed products, especially the use of small and exquisite handicrafts for various small and exquisite gifts, a large number of small printing equipment and accessories have a broad market and form a new category of applications. Such as multi-functional plastic (glue glue) machine has become a hot commodity in the current market. This gluing machine features include: speed adjustment, humidity and pressure control, liquid crystal display, pre-school function, bottom equipment, general plastic and cold laminating glue adjustment. Some gluing machines can also implement color hot stamping and mounting. They can achieve ideal results in posters, inkjet print documents, leaflets or large maps. In addition, there are other origami binding, bar code label printers, etc. that have also entered the market in batches and become printing post-processing equipment.

Third, the problem analysis

1. Technical and performance issues

China has a considerable gap in the printing and finishing technology and equipment on the surface of packaging and printing, compared with the developed countries in the world, especially in the degree of automation, feasibility and adaptability of relevant technologies and equipment. Judging from the application of technology and equipment, we are still at the initial stage. As for the technical problems of the film coating equipment, domestic equipment and adhesives still have some problems to varying degrees, such as deformation problems, durability problems, separation of the film from the base paper, etc., and there are still no ideal solutions. There are also glazing and glue spraying technologies and equipment for packaging and printing surfaces, which have become the mainstream of packaging surface finishing technology and equipment abroad, and our mainstream is still the surface coating, all of which we have yet to solve.

2. Device model size problem

Because many modern products rely on characteristics and individuality to win the competition, and the selling period of a product is getting shorter and shorter, the replacement is getting faster and faster. Enterprises that are engaged in the surface finishing of packaging must have a large scale to achieve a large scale. More to rely on SMEs to complete. Therefore, while the equipment is improving reliability, equipment models tend to be smaller and smaller to accommodate changes in the market.

3. Energy saving problem

Printing equipment includes post-press processing equipment. The main energy consumption is its transmission and heating system, while the heating (drying) system is the one that occupies a greater proportion of energy consumption. Heating and drying are mostly electric heating. In the past, heating of many devices was performed using ordinary electric heating tubes (wires), which resulted in high energy consumption and high costs. Saving energy and reducing costs are the company's goal from beginning to end. Nowadays, some equipment has adopted advanced heating and conduction methods such as chemical thermal fluids, infrared heaters, and UV heaters.

4. Functional and adaptive issues

Different materials have different properties and effects. As light, some use plastic substrates, some use paper substrates, and some use synthetic substrates. This does not require its equipment to meet the glazing of these substrates and achieve the desired results. In addition, there are water-based, oily, solvent-based, etc. In addition, a new type of special coating has emerged, so the finishing equipment should be able to meet the finishing requirements of these materials, which also requires a wide range of equipment adaptability. In addition, as far as companies are required to occupy as little equipment and space as possible, as many as possible to complete a variety of finishing operations, in order to reduce processing and storage and transportation costs. As a result, multi-functional coating calenders, laminating machines, calendering machines, and glazing machines have appeared one after another.

5. Reliability problem

Reliability is the first consideration in the design of any packaging and printing equipment. The fierce competition in the market requires that the equipment can quickly adjust according to customer's product requirements, replace different components and institutions, and can easily operate and reliably control and operate, so as to improve the accuracy and high efficiency of processing.

Surface finishing technology has been applied to a variety of non-professional areas. Such as all kinds of daily necessities, stationery, decorative items, handicrafts, etc., many of the staff used do not have professional skills and operate less well than professionals. This requires mature technology and reliable equipment. Reliability is an important guarantee for the extension and penetration of packaging and finishing equipment and technology to other industries and fields.

Source: Greater China Graphic Arts Network