Polyurethane high efficiency catalysts are specially designed to catalyze and promote the curing and drying chemical reactions of various polyurethane materials such as polyurethane coatings, paints, adhesives, sealants or pastes. It is a compound of a variety of special rare metal organic compounds and other active organic compounds.
Calcium carbonate is mainly divided into two categories: heavy calcium carbonate, also called white powder, terrazzo powder, calcite powder, three fly powder and so on. It is made of natural marble and calcite by wet grinding into stone powder, separated by water bleaching, precipitation, drying and crushing. There is also a dry grindstone powder, which is separated by air bleaching by dry pulverization, and the fineness of the qualified part is selected. The relative density is 2.5~2.8, and the refractive index is 1.59. Its technical indicators are shown in Table 23-17.
Precipitated calcium carbonate is also called light calcium carbonate. It is lightweight and has a small particle size polyamide wax ingredients. It is an alkaline extender pigment with an oil absorption of 69%-95% and a particle size of 10-20pm. The relative density of precipitated calcium carbonate is 2.7 to 2.8, the refractive index is 1.59 to 1.66, the relative molecular mass is 100.09, the pH is 7 to 9, and the Mohs hardness is 2.5.
Precipitated calcium carbonate (light) in a narrow sense refers to a calcium carbonate product that meets the national standard GB4794-84 crystal as a spindle, that is, precipitated calcium carbonate produced by chemical methods, with an average particle size of 2.56um.
The specific surface area is about 5m²/g, the whiteness is about 90%, and the relative density is 2.6.
Changing the process during the production of precipitated calcium carbonate can produce fine calcium carbonate crystals. Due to different crystallization conditions, it can become cubic, needle-like, spherical, and chain-like fine calcium carbonates. Generally, it is divided into fine calcium carbonate, fine calcium carbonate, fine calcium carbonate, ultrafine calcium carbonate, and ultrafine calcium carbonate according to the size of the grains.
Heavy calcium carbonate is made of natural calcite, limestone, white, and shells as raw materials, which are ground mechanically to a certain degree of fineness.
The product has impure properties, irregular and rough particles, wide particle size distribution, and color changes with different raw materials. Because the sedimentation volume is 1.1~1.4mL/g, which is relatively heavier than precipitated calcium carbonate, it is commonly called “heavy calcium carbonate”. , The products are divided into single fly powder (200-day sieving), double fly powder (320 mesh sieving), and four fly powder (400 mesh sieving) according to their fineness levels.
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