Preparation method of high temperature resistance ultrafine active calcium carbonate

Abstract

The invention provides a preparation method of high temperature resistance ultrafine active calcium carbonate, and relates to the technical field of preparation and processing of calcium carbonate powder. The preparation method comprises the following steps of S1, preparing an ultrafine calcium carbonate slurry; S2, adding a dispersing agent into the ultrafine calcium carbonate slurry prepared byS1, and aging for 24-144 hours to obtain an aged slurry; S3, adding a surface treatment agent to the aged slurry prepared by S2, carrying out an auxiliary catalytic reaction by microwave or / and high pressure, after the surface treatment is finished, dehydrating the slurry by pressure filtration, drying, and pulverizing to obtain the calcium carbonate. The surface treatment agent is surface-hydrophilically-treated fatty acid, and the surface treatment agent accounts for 3-5% the mass of the dry basis of the calcium carbonate. The ultrafine active calcium carbonate can maintain the activation degree at 350 DEG C, and do not volatilize and turn yellow. The ultrafine active calcium carbonate can be widely applied to products having a processing temperature of 270 DEG C or higher such as BOPP and the like.

Description

technical field [0001] The invention relates to the technical field of preparation and processing of ultrafine active calcium carbonate powder, in particular to a preparation method of high temperature resistant ultrafine active calcium carbonate. Background technique [0002] Ultrafine calcium carbonate is the most widely used chemical product at present. As a new type of functional filler with excellent performance, it is widely used as an additive and a reinforcing agent. It can not only increase capacity, reduce costs, save masterbatch, but also Improve the surface color of the product and improve the comprehensive mechanical properties of the product. [0003] Due to the small particle size and high surface energy of ultra-fine calcium carbonate, it is easy to agglomerate, the surface is hydrophilic and oleophobic, and the surface properties are very different from the organic polymer matrix, resulting in great defects in the structure of the composite material. The gap...

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Problems solved by technology

[0003] Due to the small particle size and high surface energy of ultra-fine calcium carbonate, it is easy to agglomerate, the surface is hydrophilic and oleophobic, and the surface properties are very different from the organic polymer matrix, resulting in great defects in the structure of the composite material. The gap between the matrix and the filler Adhesion is a key factor that determines the final properties of the material, especially the mechanical properties. Therefore, the surface of calcium carbonate needs to be modified. The commonly used calcium carbonate surfactant is the use of fatty acids, including stearic acid, coconut oil, and oleic acid. etc. The boiling point or decomposition temperature of these surface treatment agents does not exceed 200 °C. In the process of surface modification of calcium carbonate, in most cases, no chemical bond is formed with the surface of calcium carbonate particles, and there is gelation of the auxiliary agent at high temperature. Volatile (smoke), odor and other problems

When used as a filler in products processed at high temperatures, it often causes peculiar smell and even yellowing of the product, which not only affects the appearance and performance of the product, but also causes poor dispersion of calcium carbonate in the product and affects its mechanical properties.

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