Solvent-free compounding is about to usher in a great development era

Mr. Zuo Guangshen, General Manager of Interview Machinery Co., Ltd.

Plastic composite flexible packaging has become an indispensable packaging material in people's lives. However, so far, in China, composite flexible packaging materials are generally produced using a solvent-based dry compound process, and there are serious problems in energy consumption, environmental protection, and hygiene. At present, although domestic manufacturers have adopted new types of green packaging aids such as alcohol-soluble adhesives and water-based adhesives, the use of dry-process composite production of composite flexible packaging materials has greatly improved, and has played a role in promoting the development of green packaging. Actively, however, the inherent disadvantages of the dry compounding process have not changed fundamentally. The solution of residual solvents has always made flexible packaging face two options: palliative and permanent cure. The palliatives - control of solvent residues: solvent-based dry compound (10mg/m2 → 5mg/m2 → 1.5mg/m2), but still difficult to solve the other two major problems: pollution and safety. Harmful cure: Complete elimination of solvent residues: use of solvent-free compound alternatives to dry compounding. However, in the past many years, we have still moved within the scope of the palliatives.
In today's sustainable development, people-oriented, vigorously advocated a green packaging technology with obvious resources conservation, superior environmental performance, and reliable product health performance—a solvent-free composite process—is a very urgent task for practitioners. To this end, the reporter specifically interviewed Zuo Guangshen, general manager of Guangzhou Tongze Machinery Co., Ltd., and asked him to introduce the situation of solvent-free composite technologies and equipment at home and abroad.

The gap between domestic and international market larger light left Shen first introduced the development of solvent-free composite technology. The solvent-free composite technology is one of the three most important environmental protection technologies (solventless composite technology, flexo printing and co-extrusion compounding) of contemporary international flexible packaging, and it is the most undisputed environmental protection technology. The main advantages are: a typical "three-nothing" process, that is: the whole process of production and use without pollution; the finished product (composite material) without solvent residue; due to the absence of solvents, there are no potential safety hazards during the production process. In addition, the drying (curing) energy consumption is very low, only 1/15 of the dry composite 1/15, and the use cost is lower. Fully meet the requirements of Environmental Health & Safety (EHS). The use of solvent-free composite technology instead of dry compounding not only shows obvious advantages in environmental protection, production safety, and ensuring product quality, but also has significant effects in reducing production costs and improving economic efficiency. Represents one of the development directions of composite technology.
At present, the status quo of foreign solvent-free composite technologies is: originated in the 1970s (Germany), and rapid development began in the 1980s, accounting for 80% to 90% of new composite machine equipment (Europe, USA). Japan began to pay attention in the late 1990s and has a relatively rapid development. The current status of solvent-free composite technology in China is: It began slowly in the mid-to-late 1990s and has been developing slowly. In recent years, it has developed slightly faster. The number of existing installations does not exceed 40 (accounting for less than 2% of the total number of composite machines), which is far lower than that of developed countries.

Many factors constrain the development of technology When it comes to the reasons why solvent-free compounding is slow to promote in China, Zuo Zong said that there are many reasons for this, but the main reasons are: First, the pressure on domestic companies is not enough. For a long time, people’s concerns about health, government and market requirements for environmental protection and safety have not put enough pressure or encouragement on packaging and printing companies. Second, long-term propaganda is misleading. For a long time, many propaganda paradoxes have described solvent-free compounding as simple, easy-to-control, and all-substrate-appropriate processes. However, in reality, it is a process that is simple in principle but difficult to grasp, and is not suitable for all materials. The compound. Therefore, almost all companies in the early stage are not expected to be difficult to promote the technology. Third, there are not many successful early adopters. It has been more than 10 years since the introduction of this technology in China. However, almost all manufacturers have experienced many twists and turns in the process of use. There is no easy way. Many devices have not entered normal use, resulting in a large number of latecomers to this. The technology is either far away or does not stand still, resulting in a typical situation of “say good or bad”. Fourth, the characteristics of the process itself are more complicated. This process technology is quite different from the commonly used dry-type composite process, and there is not enough mature experience to learn from it. Foreign experience cannot be applied directly. Domestic companies need to work harder and harder.

Environmental challenges to promote industrial upgrading But for now, the most important development trend of international flexible packaging is EHS (environmental protection, health, safety) has been widely recognized in the country. The country’s supervision over food safety has been significantly increased. For example, QS certification is an important national initiative. People’s concern for health and safety has also been significantly improved; in particular, the newly revised additives for food containers and packaging materials will be introduced. The standard (GB9685-2008) will have new standards in particular for the use of solvents in adhesives and inks.
In this regard, Zuo Zong also agreed that the promotion of solvent-free compounding in China has some new favorable conditions, which has injected new impetus for the promotion of solvent-free compounding. The development of homemade equipment and adhesives has made qualitative progress and provided favorable conditions for promotion. In particular, the newly developed SSL series solventless laminating machine developed by Guangzhou Tongze Machinery Co., Ltd. has occupied a leading position in the domestic market and reached the advanced level of similar foreign products, and fully satisfies the domestic large-scale promotion of technical conditions. In particular, the solvent-free composite "31" promotion plan of Tongze Company will provide a strong guarantee for domestic companies to adopt solvent-free composite technology. Tungze company based its solvent-free composite equipment technology on its two main reasons. First, the product orientation was determined from the very beginning to environmentally-friendly equipment and technology. Solvent-free compounding is just one such technology, and it has always been in the country. Secondly, as a new enterprise, we hope to conduct product development and marketing in a professional manner at a starting point where a domestic colleague has not yet arrived, and avoid repeating the path of others. In addition, there has been a wide gap between domestically produced equipment and the market demand has obviously increased in recent years. This is also an important reason.

When independent innovation promotes development, when talking specifically about the solvent-free composite “31” promotion plan, Zuo Zong said that Chinese companies adopt solvent-free compound technology. From the operational level, there are three main difficulties: equipment difficulties, process difficulties, and the difficulty of the captains. .
The difficulty of equipment includes two aspects: the high price of imported equipment, most companies are difficult to purchase; equipment requirements are high, and manufacturing is difficult. At present, the import of a set of equipment requires approximately RMB 2.5 million to RMB 4 million (excl. tax), and many companies have difficulty in purchasing it. Therefore, there is a large restriction on the promotion of this technology in large areas. On the other hand, solventless laminators are more difficult to manufacture. Due to the high requirements of coating mechanisms, tension systems, machine speeds (250 m/min to 300 m/min) and high safety requirements, traditional methods of manufacturing dry duplicators (speeds of 100 m/min to 150 m/min) are impossible Get the equipment that meets the requirements for use. From an experience point of view, solvent-free laminators require new technical specifications and manufacturing methods, and the threshold is significantly higher than that of dry laminators.
Difficult process refers to the difficulty in matching the equipment, substrate, adhesive, and process parameters of solvent-free compounding. The main reasons are: First, the tension control is difficult because the initial adhesive force is very low, and the control of setting the tension in each section is Very strict. Second, the control of the coating amount is difficult, mainly because of the sensitive control parameters (6 to 7), the amount of glue applied, and some parameters. Third, due to the curing time required, the composite results appear to lag. Fourth, due to the generally high production speed, the overall control of the production process is more difficult. Therefore, the difficulty of process control and the risk of rejects increased significantly.
The captain has two difficulties. First, it means that the qualified captain is difficult to find, and the second is that the qualified captain is difficult to train. There is no shortage of qualified captains or supervisors in solvent-free composites in China. In our country, it is not difficult to find the captains and supervisors of 10,000 dry reclaimers, but it is very difficult to find the captains of 100 qualified solventless composite machines. Secondly, training a qualified solvent-free laminating machine is far more difficult than training a captain of a dry laminator. This captain not only requires sufficient operating experience, but also requires a higher theoretical foundation and multidisciplinary knowledge. Take traditional training mode.
Zuo Zuo introduced that a solvent-free composite technology promotion training plan for China's solvent-free compounding situation, especially the above-mentioned three difficulties (ie, equipment difficulties, process difficulties, and pilots' difficulties), is called the “Three-One” plan of Tongze. Trinity Program) refers to providing customers with a set of equipment, a set of processes and a captain training program. These three items constitute an organic whole, the specific content: a set of equipment, through a series of long-term research and development of the company's solvent-free complex machine, will become a flexible packaging standard type of composite machine, it currently has SSL1300 and SSL1000 two models, The main features are: precise control of coating amount; high compound quality; high humanity; good machine safety, stability and reliability; The reason why these characteristics are mentioned above is that in designing this series of models, all the key parts have undergone in-depth research and adopted a number of patented technologies. Of course, we also use a lot of quality assurance measures in the processing and assembly engineering. From the live demonstration, the machine is still very smooth and smooth at a speed of 320 meters/minute, with a coating weight of about 1.4 grams per square meter, which is comparable to imported equipment. Including the SSL series of solventless laminating machines and supporting equipment tools (glue mixers, heating machines, refrigerators, exhaust fans, tools, etc.), ie "1+5 solutions". The appropriate supporting equipment and tool manufacturers will be selected to form a supplier team for domestic and foreign markets.
A set of processes is to provide general process procedures and parameter determination methods that can produce qualified products for different composite substrates and process parameters of a typical product. We promise that before the equipment is ordered, we can trial production of a product sample that meets the requirements of the user for a fee; before the equipment leaves the factory, a product sample (including its main production process parameters) that satisfies the use requirements can be provided free of charge.
A captain training course is a course that trains qualified captains or supervisors to train a large number of captains and supervisors who have a certain theory and skillful operation through theoretical learning, on-machine operation and other links. "Solvent-Free Composite Technology Training Course" includes chapters on Solventless Compound Process Principle, Solventless Compound Machine Structure and Conditioning, Adhesive Properties and Applications. The tutorial focuses on the application, but it also introduces the theory and it can be completed shortly after it is written. We will cooperate with the Yinhui Branch of the China Press Association to use the strength of the cooperative enterprises to run the training courses. The goal is to train a large number of captains and supervisors who have a certain theory and skilled operation, and strive to achieve at least one qualified captain for a solventless laminator.
Finally, Zuo Zong gave reporters a set of relevant statistical data: The solvent-free compounding technology has very low energy consumption for drying (curing), which is only 1/15 to 1/25 of that for dry compounding, and the energy-saving effect is very obvious.