Siloxane ester, KH-560 and KH-570 were used as precursors to prepare silicone wear-resistant coatings on epoxy resin by sol gel method combined with spin coating. The properties of the coating were tested by pencil hardness test, cross cut test and self-made wear resistance test device. The surface morphology of the film was observed by SEM. The results show that the stability and adhesion of the coating can be effectively improved by proper coupling agent; the hardness and wear resistance of the coating increase with the increase of heat treatment temperature within a certain temperature range; the surface hardness and wear resistance of the epoxy resin are obviously improved after coating, and the surface quality is obviously improved.


1 Introduction

Epoxy resin is widely used because of its low density, strong impact resistance, good mechanical properties, electrical insulation and good thermal and chemical stability. However, due to its low hardness and poor scratch resistance, its application is limited to some extent. The preparation of silicone wear-resistant coating on the surface of epoxy resin can effectively solve these problems 。 In recent years, the preparation of functional thin films by using Luo gel gel method (sol-gel) has been considered to have a bright future. Compared with other traditional coating methods, sol-gel method has many advantages: it is easy to realize the combination of multiple components, low process temperature, uniform product structure, high purity, easy to control the reaction process, easy to form film by sol. In particular, the low temperature of the process provides a convenient way to introduce organic components or organic functional groups in the inorganic skeleton network and create specific functions of the system. One of its applications is to plating a hard protective film on the surface of the objects with insufficient hardness, poor wear resistance and easy damage. The composite film with inorganic coating on the surface and organic coating in the middle can be obtained by selecting suitable precursor, which not only meets the need of scratch resistance, but also takes into account the tight bond between the film and the substrate. In this paper, tetraethoxysilane and γ - glycidyl are selected! After KH-560 and KH-570, Rockwell gum was prepared. The inorganic organic wear-resistant coating was prepared on the surface of epoxy resin by rotary coating method.

2 experiment

2.1 preparation of dissolved limb

Mix TEOS, Siwan coupling agent, ethanol and acetoacetate in a certain proportion, slowly add a proper amount of deionized water, and then adjust the pH value of banyan liquid to about 4 with dilute hydrochloric acid, fully mix for 1-2h, and then aging for 5-6h for standby.


2.2 the preparation of the film is carried out by kw-4a sizing machine with the rotating coating method. The speed of rotation depends on the size of the element, the concentration of the coating solution and the thickness of the film. Under the action of centrifugal force, Rongye forms a uniform colloidal layer on the surface of the whole component. After the solvent on the surface evaporates, it is dried and solidified in the air blast drying oven to obtain the wear-resistant coating.

2.3 performance test

Pencil hardness test method is used for coating hardness test, and scratch test is used for adhesion test. Wear resistance test: place the resin sheet horizontally, and then place the 240 sandpaper on the coating surface, load a certain quality of silicon code on the sandpaper, pull the sandpaper at a certain speed during the test, so that the sandpaper can be evenly scratched from the coating surface, so as to show the wear resistance of the minimum silicon code with obvious scratches, as shown in Figure I. The surface morphology of the film was observed by SEM.