Random block type aromatic polycarbodiimide compound and preparation method thereof

Abstract

The invention provides a random block type aromatic polycarbodiimide compound which is synthesized from two types of aromatic diisocyanate by condensation reaction and end-capping reaction. The structural formula of the random block type aromatic polycarbodiimide compound is shown in the description. According to the random block type aromatic polycarbodiimide compound, the random structure is formed in random block type aromatic polycarbodiimide, so that the crystallizing degree of a molecular chain structure of polycarbodiimide is reduced; the mechanical properties are obviously improved bybeing compared with those of simple component; the optical property is obviously improved; the transparence is improved; the color of a polymer product is greatly improved; and the processing is easily carried out; the polymerizing degree is greatly increased; the thermal stability of a carbodiimide composition is improved; and the content of carbodiimide group is correspondingly increased, so that the hydrolysis resistance is improved, and moreover, the ageing resistance is correspondingly improved.

Description

technical field [0001] The invention relates to an aromatic polycarbodiimide compound and a preparation method thereof, in particular to a random block type aromatic polycarbodiimide compound and a preparation method thereof. Background technique [0002] Carbodiimide compounds have been proven to be used as excellent anti-hydrolysis agents in a series of materials such as thermoplastics, polyols, and polyurethanes. The most obvious feature of this type of material is that the molecular structure contains ester bonds. The presence of ester bonds makes this type of material prone to breakage of ester bonds and formation of terminal carboxyl groups under humidity or high temperature. The terminal carboxyl group further catalyzes the hydrolysis to accelerate the breakage of the molecular chain, which greatly reduces the performance of the material. The presence of carbodiimide compounds can eliminate the residual acid and carboxyl groups in the polymer and inhibit the occurren...

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Problems solved by technology

Among them, monomeric carbodiimides, such as the Stabaxol-1 type of Rhein Chemie Rheinau GmbH, have the disadvantage of being volatile or thermally unstable, and they may release volatile toxic compounds, so they are not Conducive to its application in high temperature processing environment

Another example is that the carbodiimide described in the patent EP 0628541A1 must be based on specific raw materials, and obtaining these raw materials is expensive, and the product also has a high viscosity at room temperature, which is not conducive to adding in the product

Polymerized carbodiimides are all in the form of a single repeating structural unit according to current reports, such as CN10250416A. The main chain of the polymer molecule exists in the form of a linear structure, which has good crystallization properties, which is not conducive to the transparency of the polymer product. Light, which limits its application field, especially in fields that require high light transmission performance, such as plastic film, photovoltaic industry and other fields

Another example is the Stabaxol-P type polymeric carbodiimide of the already industrialized Rhein Chemie Rheinau GmbH. Although the molecular weight is relatively large, it solves the shortcoming that the monomer type is easy to volatilize, is not easy to extract, and has low toxicity, but its Monophenyl diisocyanate is used as the raw material. Compared with the structure of methylene bisphenyl diisocyanate, monophenyl diisocyanate has the disadvantages of high reactivity and easy yellowing of the polymerized product, which affects the appearance and color of the product, especially for In materials with high color requirements, such as solar photovoltaic films, polyurethane soles and other materials, the problem of yellowing seriously limits its application fields

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