Modified aluminum polyphosphate antirust pigment prepared by high-temperature solid-phase one-step method and method thereof

Abstract

The invention relates to a modified aluminum polyphosphate antirust pigment prepared by a high-temperature solid-phase one-step method and a method thereof. The polyphosphoric acid and aluminum hydroxide are used as raw materials, a high-temperature solid phase is adopted to obtain an aluminum tripolyphosphate intermediate, different modifiers are added for chemical modification, and ball millingand spray drying are performed to obtain the modified aluminum tripolyphosphate antirust pigment product with proper pH value, fineness, solubility and dispersity. The main raw materials comprise polyphosphoric acid, aluminum hydroxide and a modifier, and the molar ratio of the polyphosphoric acid to the aluminum hydroxide is 2.9-3.1. The method has the beneficial effects that a high-temperature solid-phase one-step method is adopted, so that two procedures of neutralization reaction and concentration are reduced, the technological process is shortened, the production efficiency is improved, and the production cost is reduced. The problems that the modifier is added into the aluminum dihydrogen phosphate intermediate to cause many side reactions and more other generated impurity components, so that whether the reaction is finished or not is difficult to judge, and meanwhile, the product impurity content is high and the quality is poor are solved.

Description

technical field [0001] The invention belongs to the technical field of preparation of paint antirust pigments, relates to a method for preparing industrial phosphate antirust pigments, in particular to a modified polyaluminum phosphate antirust pigment prepared by a high-temperature solid-phase one-step method and a method thereof. Background technique [0002] With the development of industry in today's society, the loss caused by metal corrosion is becoming more and more serious. According to the statistics of relevant departments, the metal loss caused by corrosion is as high as hundreds of millions of yuan every year. Although there are many anti-corrosion measures at present, the most widely used method is still the paint protection method. In this method, the anti-rust pigment is an important factor affecting the protection effect. Although traditional anti-rust pigments such as red lead and chromate have excellent performance, the accumulation of the above heavy metal...

AI Technical Summary

Problems solved by technology

However, a large number of application studies have shown that although polyaluminum phosphate salts have outstanding antirust effects, they have not been able to fully replace the above-mentioned toxic pigments in some coatings such as water-based coatings and high-temperature coatings. There are some defects: for example, because a single aluminum polyphosphate has the characteristics of a solid acid, its pH is usually between 2.1 and 3.5, and its acidity is high. In practical applications, it is found that its early anti-rust performance is not outstanding, especially in water-based coatings. Among them, it cannot be directly used as an antirust pigment because it cannot overcome the problem of "flash rust" well. Usually, it is necessary to change its pH from acidic to neutral by adding alkaline or amphoteric substances on the basis of a single polyphosphate aluminum salt. , and reduce the content of heavy water-soluble salts, the modified product is usually called modified aluminum polyphosphate

[0006] The method disclosed in the Chinese patent document CN103497556A Modified aluminum tripolyphosphate antirust pigment for middle and low-end coatings and its preparation method is to modify aluminum dihydrogen phosphate as an intermediate, and its reaction mechanism is complicated. There are many side reactions between the aluminum hydrogen intermediate and the modifier, and many other impurities are generated

The resulting impurity components will make it difficult to judge whether the reaction is complete, and also cause product impurity problems and affect the quality of the product

[0007] Chinese patent document CN102226046A, a modified aluminum tripolyphosphate high-efficiency antirust pigment, discloses that aluminum tripolyphosphate is used as an intermediate for modification, then there is a process of preparing tripolyphosphate powder in advance, and the process is lengthy, and there will be secondary Disadvantages such as dryness, high energy consumption, and high cost

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