Preparation And Properties Of Abrasion-resistant Organosilicon Coating

The disadvantages of the optical plastics have restrained their utilities. While trying to redesign the structure of plastics to improve their properties, surface-treatment has been frequently used. In order to improve the hardness, various methods including abrasion-resistant coating have been demonstrated as an effective and convenient way.We already have invented an abrasion-resistant coating which was used for JD reins. It had some shortages when it was used for PC or PMMA. Based on the previous work, the components of the coatings and their effects on the properties of the coating have been studied in this work. Then the best composition that is suitable for PC and PMMA was developed. The components of double groups coating are as follows:Condensation Catalyst: moderate Both group A and B were colorless clarity, and could be preserved for at least 6months without any change at room temperature. The coating was preparedthrough mixing A and B with volume ratio of 52:8. The coating was colorless clarityand had good fluent ability. It had 13% solid content. The pH of the coating wasabout 4.5-4.8. It could be used at least for 1 month..FTIR was used to study the condensation progress of the coating. The result showedthat the Si-OH content was decreased and the Si-O-Si content was increasedbecause of the condensation reaction between the Si-OH during the condensationprogress. The Si-OH content was less and the Si-O-Si content was more in highercondensation temperature. The hardness and contact angle of the coating surfacereached a maximum value after condensation at 80℃ for 120 minutes and changedvery little afterwards. The curing condition on PMMA was at 80℃ for 3 or 4 hours.The curing condition on PC was at 120℃ for 3 or 4 hours. The abrasion-resistantability of the coating film was studied. The result showed that the condensationcatalyst and the surfactant were indispensably for increasing the abrasion-resistantability of the coating.Properties of the coating on PMMA after curing at 120℃ for 3 hours:Thickness: 2-3umTransmittance increasing: 2%~5%Abrasion-resistance: 0.1%Pencil hardness: 6HAdhesive property: Grade 1Color: colorless claritySurface state: smooth and uniformTransmittance: 94.8%These properties of the film have reached the standards of utilities.