How to choose sandpaper base paper

The matrix, abrasive, and binder are called the three elements of the coated abrasive, and the base paper substrate is the most widely used and the largest amount of material. The base paper is mainly used to produce water-resistant sandpaper, dry sandpaper, wood sandpaper, paper-based abrasive belts, and the like. In the manufacturing process of coated abrasives, the quality of the substrate directly affects the quality of the product. Due to the large differences in the manufacturing process of various manufacturing enterprises, the selection of suitable base papers will greatly help to stabilize the quality of the products. First, the status quo of the original paper manufacturing enterprises due to a special industrial paper for sandpaper base paper, the market is relatively small, the amount is not large, the annual domestic market is less than 20,000 tons, with the acceleration of China's industrialization process, there has been a large increase in recent years, but due to sandpaper The original paper requirements are special, the market profit margin is not large, the country has almost no research and development and technical support for the original paper. When the original state-owned paper manufacturers were completely disintegrated, closed or converted, the original paper production enterprises have few left, and the current paper production capacity In terms of it, only Hubei Haifeng Paper Jiangxi Lemen Paper and other companies support the development of the industry. The above-mentioned raw paper production enterprises can basically meet the needs of sandpaper production enterprises to choose raw paper, especially heavyweight abrasive paper latex paper, which all rely on imports. Now it can be produced in China, and some products can basically replace imports. However, the production of super-precision abrasive sandpaper base paper super-heavy paper-based abrasive belt base paper, due to a certain gap between the process equipment and foreign countries, can not meet the requirements of coated abrasives production enterprises, need to accelerate innovation and improve the production level of research and development capabilities. Second, the original paper selection error area 1, coarse and fine grain sandpaper with the same base paper. A coarse, fine sandpaper sanding substrate, abrasive, binder is called coated abrasives three elements, and the base paper substrate is the most widely used, the largest amount of materials. The base paper is mainly used to produce water-resistant sandpaper, dry sandpaper, wood sandpaper, paper-based abrasive belts, and the like. In the manufacturing process of coated abrasives, the quality of the substrate directly affects the quality of the product. Due to the large differences in the manufacturing process of various manufacturing enterprises, the selection of suitable base papers will greatly help to stabilize the quality of the products.

 

 

 

First, the status quo of the original paper manufacturing enterprises

 

Because of the special industrial paper for sandpaper base paper, the market is relatively small and the dosage is not large. The annual domestic market is less than 20,000 tons. With the acceleration of industrialization in China, there has been a big increase in recent years, but due to the special requirements of sandpaper base paper, market profit The space is not large, the country has almost no research and development and technical support for the original paper. When the original state-owned paper manufacturers were completely disintegrated, closed or converted, the original paper production enterprises were running out. At present, only the production capacity of papermaking equipment is Hubei. Haifeng Paper Industry Jiangxi Lemen Paper and other companies support the development of the industry.

 

 

 

The above-mentioned raw paper production enterprises can basically meet the needs of sandpaper production enterprises to choose raw paper, especially heavyweight abrasive paper latex paper, which all rely on imports. Now it can be produced in China, and some products can basically replace imports. However, the production of super-precision abrasive sandpaper base paper super-heavy paper-based abrasive belt base paper, due to a certain gap between the process equipment and foreign countries, can not meet the requirements of coated abrasives production enterprises, need to accelerate innovation and improve the production level of research and development capabilities.

 

 

 

Second, the original paper selection misunderstanding

 

1. The coarse and fine-grained sandpaper uses the same base paper. The amount of sand for a coarse and fine sandpaper has a large difference in the amount of primer and compound, and the requirements for the substrate are different. Generally, it is necessary to select quantitatively heavy base paper, and to select a quantitative light base paper. On the smoothness of the two papers, the requirements for coarse and fine grain sandpaper are also different. Due to the small size of the sand, the amount of glue is not large, the smoothness of the paper surface is high, and the surface must not have paper wool, and the coarseness is relatively loose.

 

 

 

2. The base paper does not match the binder. Since the raw paper making process is directed to the coated abrasive manufacturing enterprise to produce different quality sandpaper, the process is adjusted accordingly. For example, the choice of raw materials for A-grade paper, B-grade paper and latex paper is different. Therefore, the production process of sandpaper production enterprises should choose a suitable binder to match the original paper. Generally speaking, Grade A paper is mainly used to produce silicon carbide transparent sandpaper with epoxy resin as binder; Grade B paper is used to produce ordinary water-resistant sandpaper with alkyd resin as binder; Latex paper is produced by dry-grinding super-coated sandpaper. Epoxy or phenolic resin is used as a binder. In order to reduce the production cost, A-grade paper latex paper also uses alkyd urea-formaldehyde resin as binder. These two paper making processes are not suitable due to different process. Use a material with a low bond strength as a sandpaper binder, otherwise it will affect the wear resistance and durability. If the production process is improperly controlled, brittleness will occur, resulting in cracks, grit and paper peeling.

 

 

 

3, the original paper is confused. The base paper has the positive and negative sides. The original paper is attached to the side of the paper machine as the reverse side, and the other side is called the front side. The front is smoother and flatter. Because the equipment of the original paper production enterprise is different and the requirements of the coated abrasive manufacturing enterprise are different, the positive and negative sides of the original paper have great differences, the oil absorption is different, and the smoothness is also very different. Therefore, it is necessary to select according to the coarse and fine grain requirements of the production enterprise. Use the front and back side of the sand. There are original paper manufacturers that indicate the front and back sides when they leave the factory. If there is any indication, they can be judged by the following methods: visually observe the difference in the structure of the two sides of the paper, and fold the pattern to observe and compare. Another method is to dry the paper strips in an oven and observe the crimping method. The curling side is often referred to as the reverse side.

 

 

 

4. The base paper is overheated. Due to the difference in the manufacturing process of the base paper, the temperature resistance of the base paper is determined. The ordinary water-resistant sandpaper 70-80 °C can meet the production requirements. The rosin sizing agent A-grade base paper is used. If the paper is processed or the production exceeds 100 ° C, or the drying time is too long, the base paper It is easy to produce brittleness, and it is particularly prone to breakage and breakage. However, the use of the sizing process to produce Class A base paper can reach 120 ° C without brittleness. Therefore, the production enterprise should understand the performance of the base paper, reasonably control the temperature according to different process requirements, and use it properly to avoid damage to the substrate due to high temperature, thus leading to the quality of the sandpaper.

 

 

 

5, the greater the pulling force, the original paper is not necessarily easy to use. In the papermaking process, if the pulp fiber is not added with chemical additives, the strength is not enough. In order to improve the bonding strength between the fibers and enhance the water resistance of the paper, a certain amount of chemical auxiliary is usually added during pulping or papermaking. However, if this additive is used excessively, it will also prevent the resin from penetrating. Therefore, we often say that it does not absorb oil. It is a mistake to pursue the paper pulling force as much as possible. Only this index can not reflect the quality of the original paper, and must be comprehensively tested for other physics. Indicators such as quantification, tightness, folding resistance, absorbency, moisture, etc.

 

 

 

Third, the sandpaper base paper requirements

 

1. Appearance quality. Generally speaking, the original paper looks like a phase, and the color should be basically the same. In particular, each batch of the original paper should be consistent, otherwise it will affect the color of the trademark surface. The dust should not be excessive, and no pleats, wrinkles, curtains or perforations are allowed. In particular, various color papers cannot have spots. Three smoothness, the paper surface is required to be flat, the felt marks can not be too obvious, the quantitative and thick thickness on both sides should be consistent, otherwise it is easy to run off during production. The four rolls are trimmed at both ends and cannot be broken. The five paper core tubes are in good condition and the hardness is good. The weight of each large roll should not be too large. Generally, 300-600kg is suitable for each roll of paper according to the specification.

 

 

 

2, internal quality. Firstly, the sandpaper base paper should be made of 100% sulphate softwood pulp. You can't choose “sandwich paper”. Add a certain amount of waste paper pulp to the paper layer when the original paper is made, and then use the pulp surface. The appearance looks no different from the original pulp production paper. . Second, according to the production of different varieties, select the appropriate quantitative base paper, fine-grained light paper, heavy-grained heavy-duty heavy-duty paper, the higher the quantitative, the higher the strength. Third, you should choose the appropriate degree. The tightness is too large, the paper structure is compact, the strength is large, but the softness is poor. On the contrary, the tight small paper structure is loose, although soft, but the strength is low. Four should have a certain water resistance. The water absorption performance is small, avoiding moisture absorption deformation, especially after the sand is dried and deformed. In particular, the production of water-resistant sandpaper requires that the base paper has a good water resistance. The fineness of the five base paper fibers is good, especially for the production of transparent sandpaper. If the uniformity of the base paper is not good, the oil absorption will be uneven, and there will be spots or curtains. Six production of ultra-precision grinding and polishing sandpaper base paper heavy-duty strong abrasive belt base paper, due to the gap between domestic raw paper and foreign original paper, currently only foreign products can be used in this field, but the production of round sanding disc, low-grade paper tape, domestic paper can be used .