Coated polycarbonate

Abstract

The invention relates to an organic polymer with a coated surface, in particular relating to coated polycarbonate. The invention is realized by the following technical scheme: the coated polycarbonate comprises a polycarbonate substrate layer and a coating layer, and the coating layer consists of a titanium oxide bottom coating layer, a chrome coating layer and a titanium oxide surface coating layer. The invention is applicable to various aspects like mechanical industry and transparent materials.

Description

technical field [0001] The invention relates to an organic polymer for surface coating, in particular to a coating polycarbonate. Background technique [0002] Polycarbonate is a kind of transparent engineering material containing carbonate in the polymer chain, abbreviated as PC in English. Polycarbonate has low density, light weight, high visible light transmittance, good heat resistance, good cold resistance, high impact strength, high rigidity, good electrical properties and good processing performance, so polycarbonate is a thermoplastic engineering One of the fastest growing materials in plastics, it is widely used in machinery industry, transparent materials, etc., but polycarbonate also has its disadvantages that cannot be ignored: [0003] 1. Stress cracking is prone to occur under certain application conditions. The reason is that its molecular chain is not easy to slip under the action of external force, which limits the orientation and crystallization of the mol...

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Problems solved by technology

[0003] 1. Stress cracking is prone to occur under certain application conditions. The reason is that its molecular chain is not easy to slip under the action of external force, which limits the orientation and crystallization of the molecular chain. Once oriented, it is not easy to relax, so that the internal stress is not easy to eliminate. The phenomenon that the internal stress is frozen;

[0004] 2. Poor fatigue strength and wear resistance. Although it is superior to general plexiglass in terms of hardness and scratch resistance, such as polymethyl methacrylate, it is still difficult to meet many practical requirements;

[0005] 3. The melt viscosity is high, and the melt molding is difficult;

[0006] 4. Poor chemical stability, resistant to water, dilute acid, oxidizing agent, reducing agent, salt, oil, aliphatic hydrocarbon and cycloalkane at room temperature, but not resistant to alkali, amine, ketone, ester and aromatic hydrocarbon, polycarbonate can dissolve In dichloromethane, dichloroethane, cresol, dioxane and chlorobenzene, it can be destroyed by aromatic solvents of most chlorinated hydrocarbons, organic solvents such as esters and ketones and their vapors and cause stress cracking

Chromium is mostly used as the coating during electroplating, but electroplating will produce hexavalent chromium, which is highly toxic, consumes water, electricity, and consumables, and the process is relatively complicated, which limits its application.

[0008] Aluminum and chromium are mostly used as coatings in vacuum plating. Although aluminum is widely used because of its low price, high reflectivity, oxidation resistance and easy electroplating, it is soft and easy to wear, and it is not resistant to alkali, CO2, etc. Corrosion resistance, once the surface coating is damaged or not dense, the aluminum layer will be damaged; compared with aluminum, chrome has a more beautiful silvery white luster, good physical properties and more stable chemical properties, so vacuum chrome plating is a It is a better choice, but the melting point of chromium is 1900°C, and the vapor pressure of chromium at 1397°C is 1.33Pa. It is difficult to use the evaporation method, but the color of the chromium coating obtained by the general magnetron sputtering method is often obvious. It deviates from silvery white, and ion chrome plating requires the bottom coating to have high heat resistance and radiation resistance, otherwise it is easy to damage the bottom coating and cracks and other defects. Organic coatings such as polybutadiene and alicyclic epoxy resin coatings are used , can improve the heat resistance and radiation resistance of the bottom coating, but this improvement is still limited and cannot meet higher requirements. On the other hand, the surface hardness, scratch resistance, wear resistance and Performances such as aging resistance and corrosion resistance have also been greatly restricted, and they cannot meet the higher requirements of products; in addition, because polycarbonate has good application potential, in addition to in-depth research on various modification technologies, vigorously develop advanced , surface treatment with environmental protection and energy saving characteristics is also important and urgent

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