Method for preparing composite microsphere of polymer-nano magnesium hydroxide

Abstract

A process for preparing the composite polymer-nano magnesium hydroxide microspheres includes sphericizing the magnesium hydroxide nanoparticles by use of polymer monomer, cross-linking agent and trigger, and the simulative emulsion polymerizing method and spray drying. Its advantages are high product performance in coated rate, quality, flame retarding, compatibility, etc.

Description

technical field [0001] The invention relates to the preparation technology of inorganic flame retardant magnesium hydroxide, in particular to a preparation method of polymer-nanometer magnesium hydroxide composite microspheres. Background technique [0002] Most of the polymer materials widely used by modern humans are combustible or combustible in the air. Therefore, a considerable part of the fires are caused by direct ignition of polymer materials. What's more serious is that when the polymer material is burned, it will produce toxic, harmful and even corrosive gas and smoke, which will cause the trapped person to suffocate and die. According to statistics, nearly 80% of fatal accidents in fires are caused by this. In view of this, all developed countries in the world attach great importance to the development of flame-retardant polymer materials. [0003] Magnesium hydroxide is an additive inorganic flame retardant with triple functions...

AI Technical Summary

Problems solved by technology

[0004] However, ordinary magnesium hydroxide is mostly hexagonal crystal or amorphous crystal, with many hydroxyl (-OH) groups on the surface, strong agglomeration between crystal grains, and poor dispersion in resin, so it is difficult to mix with magnesium hydroxide. material compatibility

In order to make magnesium hydroxide qualified as a flame retardant, one method is to carry out hydrothermal treatment to make it a fibrous needle-like crystal to reduce its specific surface area, but after this treatment, its addition usually exceeds 50%. Above, the material can meet certain flame retardant requirements, and other properties of the material (such as impact strength) will deteriorate, which increases the processing difficulty of the polymer. Obviously, this traditional method to endow the material with flame retardancy is to sacrifice or reduce At the expense of some valuable properties of the material; another method is to carry out ultra-fine processing of magnesium hydroxide, that is, in the preparation process of magnesium hydroxide, nanometer (at least one dimension is less than 100nm) particles are made by special technology, Since the performance of the flame retardant effect is dominated by chemical reactions, the smaller the particle size of the same amount of flame retardant, the larger the specific surface area, and the better the flame retardant effect, but only for ultra-fine, magnesium hydroxide There will still be some problems during use. Secondary agglomeration is a common phenomenon of ultrafine particles. The agglomerated ultrafine particles will form agglomerates, and the internal particles are arranged in the closest packing way, and there are gaps between the particles. Stress concentration bodies will be formed after the surface is further wrapped by polymers. Therefore, in the process of material processing, strong stirring, mixing, kneading or rolling are required to destroy and prevent the generation of agglomerates

In addition, using surfactants or coupling agents to modify the surface of magnesium hydroxide is also a method, but the products made after molding and processing with polymer materials will cause surface blooming when exposed to humid air for a long time