Method for modifying nano calcium carbonate and polyolefin master batch containing nano calcium carbonate

Abstract

The invention provides a modification method of nano calcium carbonate and polyolefin master batch containing the nano calcium carbonate. The modification method comprises the following steps: coupling agent (a boric acid ester or an ester aluminate) is added in nano calcium carbonate slurry at 70 DEG C to 90 DEG C, and the pH value of the system is controlled within 8 to 10 so as to carry out the surface treatment of nano calcium carbonate; and then the nano calcium carbonate is collected after surface treatment. The modification method, which selects novel coupling agent and adopts wet-way coating modification, solves the problem that nano calcium carbonate agglomeration is easy to occur in polyolefin product, thereby making full use of the performance of nano calcium carbonate; moreover, the modification method improves the mechanical property of calcium carbonate-filled polyolefin product and the adaptability to the manufacturing temperature of polyolefin so as to avoid the problem of material surface yellowing caused by the addition of nano calcium carbonate at a higher manufacturing temperature.

Description

technical field [0001] The invention relates to a surface-modified nano-calcium carbonate, a polymer composition containing the nano-calcium carbonate and a preparation method thereof. Background technique [0002] Polyolefin is a general-purpose synthetic resin product widely used at present, and its output ranks first among all kinds of general-purpose plastics. Polyolefin can be used to make various packaging films, agricultural films, heat shrinkable films, cables, pipes, packaging containers, etc. Among them, film products are used in the largest amount. [0003] Calcium Carbonate (CaCO 3 ) is a widely used inorganic filler that can be applied to polyethylene (PE) and polypropylene (PP) products. Due to its small particle size and high surface activity, compared with traditional calcium carbonate, when it is used in polyolefin products, it has little effect on the overall performance of the material. In some cases, it can even improve the material's Certain aspects o...

AI Technical Summary

Problems solved by technology

[0006] Although the above patented methods have improved the dispersion performance of calcium carbonate in polyolefin, but because the application fields of polyolefin products are not the same, the performance requirements of the products are also different, so it is difficult to have a general-purpose nanometer that can meet the requirements of various application fields. Calcium carbonate filled polyolefin products must be improved according to the specific requirements of the application field

The method adopted by most patents is to dry-modify commercial calcium carbonate in a high-speed mixer. Since nano-calcium carbonate is easy to form agglomerates, the effect of this modification method is not obvious

[0007] In addition, the surface of commercially available nano-calcium carbonate is mostly coated with stearic acid or fatty acid salt (such as Chinese patent 01126405.5 or 03817235.6 or 200310122700.X), but the temperature resistance of stearic acid is poor. When it is higher than 180°C, it is easy to turn yellow and change color, and the temperature usually used in plastic processing is more than 200°C, so the nano-calcium carbonate coated with fatty acid or fatty acid salt is not suitable for filling polyolefin products