Views:11 Author:Site Editor Publish Time: 2021-04-21 Origin:Site
Wet-laid web refers to the production method of "the process of dewatering and forming fibers dispersed in water into a web". It is obviously different from dry-laid and polymer extrusion webs, and the products produced have unique properties.
1) Good web evenness
Wet-laid webs are suitable for fiber lengths ranging from 3 to 40mm. They are long fibers in the paper industry and short fibers in the textile industry. With the guarantee of existing fiber dispersion technology, the fibers can be fully dispersed, and can be quickly made at low concentration and constant pressure on inclined nets. Under these conditions, satisfactory web uniformity and fluffy structure can be obtained.
2) Consistent fiber web quantitative
The isobaric sizing and full-flow dewatering process design of the inclined net fully guarantees the uniform and consistent net formation, and is also suitable for low-quantity papermaking. The upper limit of the papermaking quantitative is determined by the fiber dewatering characteristics, the production speed and the dewatering pressure difference of the inclined net.
3) Mixing of different fibers
The fiber characteristics are directly expressed on the fiber web, and different fibers are mixed to wet-laid the web to give play to different fiber characteristics. For example, by mixing viscose fiber and wood pulp fiber, a wiping product with satisfactory overall performance can be obtained. Another example is the high-strength insulating aramid paper, which is obtained by fully mixing short and straight chopped fibers with good strength, good bonding properties, and pulp-like fibers, and then wet-laid and hot-pressed.
4) The direction of the fiber web is controllable
Wet-laid webs use the difference in speed between the pulp and the web to generate hydrodynamics to control the fiber arrangement direction and adjust the fiber web's longitudinal and lateral performance ratio (MD/CD). The MD/CD of the diagonal net can reach 1.1:1～2.8:1, which is equivalent to the air-laid process ability, which provides convenient conditions for copying non-woven fabrics with consistent vertical and horizontal tension.
5) Make full use of short textile fibers
The length of wet papermaking fibers is mostly below 20mm, which provides conditions for the use of short fibers in textiles. From the wet papermaking fiber length strength test, we can see that when the fiber length exceeds 12mm, the growth trend of fiber web strength is flat and slow, and wet papermaking in order to effectively ensure fiber dispersion and improve the quality of the web, try to control the fiber length to reduce copying costs and strengthen the reinforcement process.
6) Full play of fiber function
When the wet-laid web is made with a multi-layer inclined web, it provides equipment conditions for the function of different fibers. According to different performance requirements, select fibers to be copied on a multi-layer inclined wire. For example, a three-layer diagonal net is used for making 1200g/㎡ special cardboard. The surface layer and bottom layer are made of high-grade cotton-wood pulp fiber. The core layer uses the subsequent process to lose paper material. It saves resources and effectively reduces production costs.