The perforation problem of composite woven bag
Film-coated woven bags are three-layer or more than three-layer woven bags, such as bright film woven bags, matt film composite woven bags, pearlescent film composite woven bags, aluminized composite woven bags, paper-plastic composite woven bags, etc., also available Use with inner film bag.
No matter how the plastic woven cloth is coated with a layer of plastic film, it will cause airtightness. At present, in the use of this kind of film-covered woven bag, it is necessary to ensure that the cement is filled in time under a certain wind pressure during filling, and it is also necessary to achieve the purpose of moisture-proof during transportation, loading and unloading, and storage. At present, only micro-holes can be pierced on the surface of the film-covered woven bag, and there is no other technical method to replace it. Laminated woven bags are the same as other structural packaging bags. In addition to satisfying the basic functions of packaging cement, they must also solve the problems of exhaust, temperature resistance and moisture resistance during cement filling. The perforation problem of the laminated plastic woven bag is the key to solving these technical problems.
Most cement companies use gas conveying cement filling methods during cement filling. The exhaust problem during cement filling cannot be solved. One is that the filling efficiency is affected, and the other is that the bag weight qualification rate does not meet the requirements.
For the film-covered woven bag, it is also necessary to consider the problems of running, emitting, ash leakage during filling and moisture prevention during transportation. The vent is large, the number of holes is large, the vent performance is good, and the filling efficiency is high, but the cement runs out seriously during filling, and the moisture resistance is poor; the vent is small, the number of holes is small, and the exhaust performance is poor. Low efficiency, but less cement runaway during filling, and good moisture-proof performance.
Through the laminated plastic woven bag treated in this way, the gas is easily discharged from the inside to the outside during filling, which meets the exhaust requirements during cement filling, and can also ensure the pass rate of the bag weight, and at the same time, it can run off during filling. The gray phenomenon has also been resolved.
The packaging bag filled with cement is automatically closed after the exhaust hole contacts the belt during the contact with the belt conveying process, which better solves the moisture-proof performance of the cement packaging during the transportation and storage process. Because the cement production technology and equipment level are different, the cement exit temperature is also different, generally between 50 ℃ and 100 ℃. If the quality of the base fabric of the laminated plastic woven bag can meet the GB8974 national standard, the temperature resistance problem of cement packaging can be completely solved.
When the cement exit temperature is high, the thickness of the laminated plastic woven bag can be appropriately increased. If one-sided pursuit of cost reduction is adopted, inferior plastic raw materials are used, and excessive additives are added, the process conditions are unstable, and the equipment level cannot meet the product quality requirements. Even thicker plastic woven bags cannot fundamentally solve the temperature resistance problem of packaging.
