The paper industry has used blankets for more than 1000 years. Today, the paper blanket has become a product with a wide variety, high technology content and unique value. The rapid development of paper blanket makes it a new industry. In order to facilitate communication, the editor classifies the paper blankets as follows (as shown in Figure 1).

Figure 1 Classification of paper blanket

1、 According to the process of blanket development

The development process of China's paper-making blanket is similar to that of the world's, but due to historical reasons, the origin and development of China's paper-making blanket lags behind many years abroad. So far, paper-making blankets have basically experienced three development processes (as shown in Figure 0-1). According to this development process, we divide paper-making blankets into three categories.

1. First generation paper blanket

This is the first special blanket for paper making. The type of blanket used is woven blanket. Woven blankets are usually made of wool yarn or blended yarn by weaving, through traditional processes such as spinning, twisting, warping, weaving, shrinking, washing, drawing, singeing and finishing. Its structure is characterized in that the longitudinal and transverse direction are woven by spinning, and then the final product is made by mechanical shrinkage. The fiber content of the yarn is mainly wool, and a small amount of synthetic fiber is added. At present, this kind of blanket is rarely used except for some old paper machines which produce special paper (such as striped kraft paper) for blanket application. The main reason is low strength and short service life.

2. Second generation paper blanket

In order to improve the performance and prolong the service life of paper-making blankets, the second generation of paper-making blankets, mainly needled flocking blankets, also known as Bob blankets, have been developed and produced. Needled flocking blanket is composed of two parts: base cloth layer and fiber layer.  According to different fiber materials, it can be divided into mixed needled flocking blanket and all chemical fiber needled flocking paper blanket. According to the different structure of the base cloth, it can be divided into weft needled flocking paper blanket and weft free needled flocking paper blanket.

The structural characteristics of the needled flocking paper blanket are as follows: the base cloth, which is weaved by spinning or only arranged by meridional yarn in the longitudinal and transverse directions, is made of wool mesh on one or both sides of the base cloth, and the base cloth and wool mesh are 100% synthetic fiber. This kind of blanket has the advantages of large strength, stable specification, small elongation, high line pressure and load, wear resistance, semi compression property, long retention time of elasticity and porosity. It is resistant to weak alkali and acid. It is easy to be damaged when working for a long time under acid condition. The warp twist of this kind of blanket is higher, and the blanket mark will be left when the thread pressure is too high. Due to the use of dry setting, the blanket surface is not soft enough, and it needs a certain period of softening process after being put on the machine. It is usually used in the paper machine with press dehydration and vacuum dehydration, which is suitable for the varieties with large specifications and low requirements for blanket surface, such as toilet paper, corrugated base paper, box board paper, etc. For the paper with high requirements for blanket surface, the fine warp thread and thick wool layer structure are generally selected, and the application effect is also ideal.

3. The third generation paper blanket

Through the efforts of experts, the third generation of paper-making blanket has been used for many years. This kind of blanket is the needled blanket with high-speed bottom pressing net, also known as BOM paper-making blanket. BOM paper-making blanket is the most popular paper-making blanket at present, and its usage rate has reached more than 95%. The needled paper-making blanket with high-speed wire pressing bottom net is composed of bottom net layer and fiber layer. Its structure is characterized by that the bottom net layer is composed of a net with different organizational structure made by different weaving technologies in longitudinal and transverse directions, which is composed of single layer, double layer, multi-layer or multi-layer. In longitudinal direction, it is made of multifilament fiber material, in transverse direction, it is made of single or multifilament composite fiber material, and then the two sides of the bottom net are pricked with wool net As for the blanket, the bottom net and the wool net are 100% synthetic fibers. Therefore, the high-speed wire pressing bottom net needled paper-making blanket can be divided into single layer, double layer, multi-layer, laminated bottom net needled paper-making blanket and non node bottom net needled paper-making blanket.

2、 According to different parts of blankets

1. Formed blanket

As the name implies, this kind of blanket is mainly used in the forming part of paper machine. The forming blanket is mainly used in the forming part (net part) of single round net, multi round net and super forming paper machine, but people can also classify it as the pressing blanket. The forming part of this kind of paper machine has higher requirements on the paper uncovering (belt) performance, water filtering performance, breaking strength, dimensional stability and so on.

2. Press blanket

This kind of blanket is mainly used in the press part of paper machine and plays a key role in the whole process of press and dehydration of wet paper. According to the structure and dehydration conditions of the press device, the press blanket can be divided into: ordinary press blanket, compound press blanket, supporting press blanket, vacuum return blanket, light press blanket, groove press blanket, vacuum press blanket, large roller press blanket, shoe press blanket and hot press blanket. According to the upper and lower parts of the blanket, the press blanket can be divided into: press upper blanket, press lower blanket According to the use order of the blanket in the pressing part, it can be divided into: one press blanket, two press blanket, reverse press blanket, etc.

People usually call forming blanket and pressing blanket wet blanket.

3. Dry blanket

In order to distinguish the forming blanket and pressing blanket mentioned above, we call the blanket used in the drying section of paper machine as dry blanket. In the drying process, the paper sheet is tightly pressed on the surface of the drying cylinder by the dry blanket, which speeds up the drying and improves the drying speed and efficiency