At present, the state pays more and more attention to the safety supervision of food and drug. At the same time, higher requirements are put forward for the safety performance and environmental protection of packaging materials. Therefore, for flexible plastic packaging, dry composite process will be eliminated due to its inherent defects. Looking for a healthy, safe and environment-friendly composite process has become an important topic in the flexible plastic packaging industry. In the 1970s, Germany invented a new green composite technology solvent-free composite. In the 1990s, this technology was introduced into China. Compared with the common dry compounding process, the advantages of solvent-free compounding introduced in this paper are as follows:
1、 Health
At present, the solvent residue in soft plastic packaging is the most important problem affecting the health of consumers and operators. Some technicians in the industry have also made a lot of technical improvements from the equipment and raw materials of dog grain bag manufacturers, but they can only reduce the residual solvent, which can not be completely avoided
No residual solvent was produced. Solvent free process completely avoids the use of organic solvents in the production process, which fundamentally solves the problem of solvent residue. Therefore, the dog bag manufacturer said solvent-free composite is a healthy composite process.
2、 Security
Fire and explosion accidents often occur in domestic and foreign flexible packaging enterprises, mainly due to improper operation or high concentration of organic solvents in the air. If solvent-free compounding is used, the use of organic solvents can be completely avoided, and the hidden danger of safety can be eliminated.
3、 Environmental protection
The solventless composite adhesive is a solid substance without any organic solvent. Therefore, it has no effect on the health of production workers. At the same time, it also realizes zero emission of organic solvents, avoids air pollution, and has obvious environmental protection advantages.
4、 Cost savings
1. The coating weight of solvent-free composite is usually 1.3-1.8g/m2, while that of dry composite is 2.5-4g/m2. Therefore, compared with dry composite, the adhesive consumption can be saved by about 50%. Although the price of solvent-free glue is high, the total cost of raw materials can be reduced by about 20%.
2. As the insoluble composite process does not need drying process, the energy consumption cost is effectively reduced. After calculation, the energy consumption cost of solvent-free equipment is 1 / 15 of the energy consumption cost of dry composite equipment.
3. From the perspective of production efficiency, the efficiency of solvent-free equipment is 1.5-2 times of that of ordinary dry composite, which effectively reduces the production cost.
Although solventless composite has many advantages, it is not widely used in China. The main factors restricting the development of this technology are as follows:
1. High requirements for equipment
Since the solventless glue has no initial adhesion, there are high requirements for the control accuracy of the equipment tension control system and coating unit. Now only the solvent-free equipment produced by Italy's nordmec company is relatively mature, but the price is high,
It is usually more than 3 million yuan, while the price of domestic drying equipment is between 1 million yuan and 2 million yuan.
2. Precise control of production process is required
The operation temperature, tension matching, coating amount and other process settings need to be accurately controlled, and different production processes should be set according to different product structure, so the process adaptation range is narrow and the operation is difficult.
3. Higher requirements for operators
A qualified solvent-free captain needs to have a good sense of responsibility and excellent operation skills, and often the operation experience is summed up from failure. Therefore, it costs a lot to train a qualified captain.
4. The application structure is not extensive
The early solvent-free composite can only be applied to simple plastic composite. With the continuous improvement of adhesive and the continuous maturity of operation technology, aluminum coating and some multilayer structure products can be produced normally. But for some materials with high rigidity, the composite appearance is not very ideal. It needs further improvement.
5. The judgment of product quality is lagging
Because there is no initial adhesion of solvent-free composite, the quality can not be determined immediately after production, and the product quality can only be confirmed after aging for 6 hours, so there is a certain quality risk.
Although there are still many problems to be solved, its advantages in health, safety, environmental protection and cost are beyond doubt. With the continuous progress of society and people's increasing attention to health and environmental protection, solvent-free composite will usher in the spring of development. http://www.ycritai.cn/