Beating is one of the most important steps for manufacturing the filter paper disc. The beating can be roughly divided into the following four methods according to the requirements for the degree of fiber cutting and splitting: (1) Long fiber free beating; (2) Short fiber free beating; (3) Long fiber viscous beating; ( 4) Short fiber vicious beating. In the actual beating operation, there are semi-free beating and semi-viscous beating between free and vicious beating; similarly, long-fiber beating refers to the mainstay of long fibers and does not exclude the simultaneous existence of short-fiber beating.
(1) Long fiber free beating The free-form beating method of the long fiber requires the dispersed paper material to become a single fiber, and the fiber is only appropriately cut short, so the beating time is shorter. The paper material produced by the free-form beating of long fibers is easy to dehydrate on the net, and the uniformity of the formed paper structure is poor, lack transparency and the surface is not very smooth, but the finished paper has certain mechanical strength.
In the past, this beating method was considered suitable for the manufacture of packaging paper and industrial filter paper, but in recent years, it has tended to believe that the packaging paper should be beaten with a low beating degree and long fiber viscous.
(2) Short fiber free beating The free-form beating method of the short fiber requires a high degree of fiber cut on the basis of dispersed fiber. This kind of paper material is also easy to dehydrate, but the fiber interweaving ability is quite poor, the tissue of the paper is relatively uniform, and the absorption capacity is very strong.
The paper material produced by the free-form beating method of short fiber is suitable for making filter paper, blotting paper, matchbox paper, and other papers that require strong absorption performance and high organization uniformity.
(3) Long fiber vicious beating The long fiber viscous beating requires the fiber to be highly split and fine fiberized, and as far as possible to avoid the fiber from being cut transversely. When making paper, the paper stock must be diluted with water to a lower concentration.
The long-fiber viscous beating paper is suitable for the production of strong thin paper, such as high beating cigarette paper, capacitor paper, and paper. The beating of capacitor paper should be beaten until the beating degree is above 90SR, but the length of the fiber should not be too long, so as not to affect the uniformity of the paper. The paper material for cement bag paper should also be made of long-fiber sticky beating, but the beating degree is only required to reach 26-30SR.
(4) Short fiber vicious beating Short fiber viscous beating requires that the fibers be highly split and fibrillated, and at the same time, the fibers are appropriately cut. This kind of paper has a slippery feel and is more difficult to dehydrate, but it is easy to form wet paper with uniform tissue on the net. The finished paper is less absorbent and has considerable strength. The short fiber viscous beating paper material is suitable for the production of general bond paper, cable paper, etc.
In the actual operation process, there are semi-free and semi-viscous beating between free beating and vicious beating. For example, for general offset printing paper, on the one hand, a certain amount of beating is required to make the paper material have a certain degree of fibrillation to improve the strength of the paper; on the other hand, the degree of beating must be controlled to avoid serious shrinkage and deformation during printing. For this reason, the beating degree is generally controlled at 30-40 SR.