The solvent-free compounding machine is mainly composed of solvent-free laminating machine (main machine) and glue mixing machine. The solvent-free compound machine mainly completes the operations of unwinding, tension control, gluing, compounding and winding, and the glue mixing machine is a special device for quantitatively conveying adhesive to the host machine. The following author focuses on the type of solvent-free composite machine, tension control and winding mode and other related content.
Single station solventless laminating machine
Nowadays, the solventless compound machine used in China basically adopts single position unwinding and winding up. This situation is determined by many factors, including the following three aspects.
(1) Due to the low initial adhesion of solventless composite, the shorter the feeding path is, the better the tension control of substrate is required. The use of single station machine has the advantages of shorter feeding, easier to ensure the accuracy of tension control and lower scrap rate.
(2) Because the solvent-free adhesive has a certain opening time, and does not need a high-temperature drying system for dry lamination (shutdown will easily lead to overheating and deformation of the substrate in the drying channel), the use of a single station solvent-free laminating machine can realize the operation of coil replacement in the shutdown state.
(3) The single position solventless compound machine is relatively simple to manufacture and has low cost. Moreover, the single station solvent-free compound machine has compact structure and small floor area, and can be operated by one person in general. In the current labor costs continue to rise, single station solventless compound machine really has a lot of attraction.
Generally speaking, most solventless laminating machines are single station machines, which account for more than 70% in foreign countries.
Double station solventless laminating machine
Double position solventless laminating machine is a solventless compound machine with two coils or core pipes installed on one unwinding frame (or winding machine) at the same time, and it can realize non-stop winding and changing. Through several years of technical reserves, especially after in-depth communication with many users, our company officially launched the first domestic slfl00oat double station solvent-free laminating machine in early 2013.
Compared with the single position solventless laminating machine, the double position solventless laminating machine has the following advantages.
(1) High efficiency. In general, the stable working speed of solvent-free compound machine is 300-600m / min, which is about 2-3 times higher than that of dry type compound machine. However, due to the need to stop the machine to replace the coil, the effective working time is greatly reduced, and the actual utilization rate of the equipment is reduced. The double position solventless compound machine can greatly reduce the speed up and down time when changing the coil, greatly improve the production efficiency, and the general output can be more than 70%.
(2) The operation intensity was significantly reduced. The coil and core tube of single position solventless compound machine need to be changed frequently. A unwinding or winding unit is replaced every 15-30 minutes on average, and the coil is replaced dozens of times in each shift. This consumes the operator's physical strength and is accompanied by a certain degree of tension, which is bound to affect the progress of solvent-free composite production and product quality. The advantage of double position solventless compound machine can avoid this point.
(3) Improve production stability. The double position solventless compound machine greatly reduces the downtime, the tension control of the equipment and the consistency of adhesive viscosity are improved, and the production stability is greatly improved.
However, there are some potential disadvantages of the double station solventless laminating machine, because of the longer feeding, the higher requirements for the tension control of the equipment, and the corresponding increase in the reject rate, which may have a more adverse impact on the solvent-free composite products with low initial viscosity. In addition, the cost of double position solventless laminating machine is significantly higher than that of single station solventless laminating machine.
Tension control of solventless compound machine
1. Tension control mode
There are two main tension control modes in solventless compound machine: one is "floating roller" type, the other is "micro displacement" type.
"Floating roller" tension control has the advantages of wide control range, wide adaptability to substrate (including tensile materials) and good fluctuation buffering, but its structure is more complex.
The "micro displacement" tension control has the advantages of high precision and sensitive response. However, due to the small detection range and little absorption of coil fluctuation, this method is generally only applicable to thick or non tensile materials.

In the actual solvent-free composite production, a solvent-free laminating machine may use the above-mentioned different tension control methods in different sections.

2. Notes on tension control
In the whole solvent-free composite process, tension control scraping is particularly important. Accurate control of tension is the premise to ensure the quality of composite membrane. For solvent-free tension control, the author has the following points to be explained.
(1) In the solvent-free composite process, the requirement of tension control is higher than that of common composite. The main reason is that the initial viscosity of solvent-free composite is low, the operation control is difficult, and the quality problems are more likely to occur. In addition, the speed of solvent-free composite is much higher than that of dry composite, so in principle, the requirements of tension control are more strict than that of dry composite. In the solvent-free composite process, the tension after coating is slightly greater than the main unwinding tension, the winding tension is slightly greater than the unwinding tension, and the winding taper is controlled within 20%. For different materials of film, the tension of each part of the composite process is also different, and even the film of the same material produced by different manufacturers should be slightly adjusted.
(2) In solvent-free lamination, we emphasize the matching of tension between two-layer composite coils, not only the accuracy of tension system itself. Under the current technical conditions, the performance and accuracy of many tension systems are very good, which can meet the needs of solvent-free composite production. But in the process of solvent-free composite operation, we often encounter such problems: it is difficult to achieve the matching of two-layer coils, which requires not only a good tension system, but also a careful understanding of the characteristics of the material itself. It is more accurate to say that the high requirement of solvent-free composite tension means that the elongation of the two-layer coil is as consistent as possible by controlling the tension, so as to ensure that the relative slip of the two-layer coil is not produced in the solvent-free composite process.
(3) The winding tension and pressure are the key points of solvent-free composite tension control. Because the bonding state of the composite membrane and the overall condition of the coil are determined by the winding tension and pressure to a large extent, the adoption of sectional independent tension and sectional tension taper is the most ideal control mode.
It should be noted that the use of sectional tension taper is mainly to make up for the need of linear tension taper on the winding tension of different materials. The use of different tension taper in different stages of winding can effectively ensure the evenness of winding and reduce the generation of core wrinkles.
Unwinding device and charging mode of solventless compound machine
1. Unwinding device
The solventless laminating machine is equipped with aluminum foil unwinding frame and common unwinding frame. In general, the path of the aluminum foil unwinding frame is short, and the smooth guide roller (because the aluminum foil is thin, fragile and difficult to stretch, the use of smooth guide roller can effectively reduce friction and coil wrinkles), and "micro displacement" tension control is often used. However, the common unwinding frame has a long path and uses groove guide roller, and "floating roller" tension control is often used.
When the aluminum foil unwinding frame is used, only one unwinding frame is in the working state, that is, the common unwinding frame is in non working state. In the process of film lamination, because two films are combined at the same time, two unwinding frames need to work at the same time,
Accordingly, two sets of tension control systems should be in operation.
2. Loading mode
There are two kinds of loading methods for solventless compound machine: air expanding shaft type and non shaft cone top type, with high reliability
The requirement of core tube is low, but the efficiency of refuelling operation is low and the operation intensity is high. Shaftless cone top loading is simple and fast, with high efficiency and low operation intensity, but it has higher requirements for core tube. At the same time, in order to ensure the safety, this loading method has higher requirements on the processing and assembly quality of equipment parts, and the manufacturing cost is relatively high.
According to the current application in domestic and foreign markets, the medium and high-speed solventless compound machine (speed is 400-600m / min) basically adopts air expansion shaft charging.
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