Synthesis Of Organosilicon Additive And Its Application In Graffiti Resistant Coating

In recent years,the losses caused by malicious graffiti have received widespread attention.Malicious graffiti affects the city’s appearance and landscape,and the cost of removing graffiti in various countries is enormous.Simply reducing the number of graffiti to solve this problem is like stopping the boiling water.Therefore,in order to fundamentally solve this type of problem,the paint industry urgently needs to develop coatings with good anti graffiti performance.In the development of anti graffiti coatings,silicone materials are a hot topic in the international research.According to literature reports,silicone materials have the characteristics of low surface tension,low surface energy,and excellent anti fouling ability.Many scientific research institutions at home and abroad have developed anti graffiti coatings based on silicone materials.In this paper,two different types of silicone additives have been synthesized through hydrosilylation addition reaction reaction,capping reaction,etc,At the same time,the synthesis process conditions of organic silicon additives were studied,and they were used as coating additives to study the graffiti resistance of coatings in the coating system.The specific research content and results are as follows:(1)Hydroxy hydrocarbon based silicone oil was synthesized by hydrosilylation addition reaction with vinyl diethylene glycol ether as the vinyl monomer containing hydroxyl and hydrogen terminated silicone oil with different hydrogen content.The effects of material ratio,reaction time,reaction temperature,catalyst amount,and hydrogen terminated silicone oil with different hydrogen content on the synthesis structure of hydroxyl hydrocarbon based silicone oil were studied.The product was characterized by FTIR,1H-NMR,13C-NMR and gel permeation chromatography.The results showed that the optimal reaction conditions were as follows:the molar ratio of vinyl diethylene glycol ether to hydrogen terminated silicone oil was 2.1,the amount of catalyst Caster was lmg·g-1,the reaction temperature was 80℃,and the reaction time was 3 hours.FT-IR analysis results show that the stretching vibration peak of Si-H disappears at 913 cm-1 and 2130 cm-1,there is no double bond peak at 1610 cm-1 to 1680 cm-1,and there is a hydroxyl peak near 3480 cm-1,which indicates that the hydrosilylation addition reaction reaction of hydrogen terminated silicone oil with vinyl diethylene glycol ether is complete;1H-NMR analysis results show that 3.55-3.75 ppm belongs to the proton absorption peak of methylene on the vinyl diethylene glycol ether chain segment,0.11 ppm belongs to the proton absorption peak of methylene connected with silicon,and 1.3 ppm has a proton absorption peak of hydroxyl,indicating that hydrosilylation addition reaction has occurred between hydrosilastic silicone oil and vinyl diethylene glycol ether;13C-NMR analysis results show that the resonance absorption peak at 19.91 ppm belongs to the connecting silicon and methylene,which corresponds to the characteristic resonance absorption peak of the connecting end hydrogen silicone oil and the carbon connected to vinyl diethylene glycol ether,and the resonance absorption peak of the carbon on the carbon carbon double bond at 151.71 ppm disappears,indicating that the hydrosilylation addition reaction reaction is complete,and the synthetic product is hydroxyalkyl silicone oil;Through GPC analysis,it can be concluded that the product distribution is narrow and in a single distribution state.The viscosity of the synthesized hydroxyalkyl silicone oil increases with the increase of hydrogen content in the hydrogen terminated silicone oil,and its hydroxyl value is within a reasonable calculation error range compared to the theoretical hydroxyl value.(2)Using the self-made hydroxyalkyl silicone oil and isophorone diisocyanate(IPDI)as raw materials,dibutyltin dilaurate(DBTDL)as catalyst,the organosilicon polyurethane capped with hydroxyalkyl silicone oil was synthesized by one-step chain extension.The effects of reaction temperature,catalyst amount,reaction time and reaction process were studied.The product was characterized by FTIR,1H-NMR,13C-NMR and gel permeation chromatography.The experimental results show that the reaction temperature is 60℃,the amount of catalyst is 0.05%(mass fraction of hydroxyalkyl silicone oil),and the reaction time is 2 hours(with a dripping time of 60 minutes).FT-IR analysis showed that a stretching vibration absorption peak of the secondary amino N-H bond appeared at 3376 cm-1,a bending vibration absorption peak of the secondary amino N-H bond appeared at 1538 cm-1,and the characteristic peak of NCO disappeared at 2240-2275 cm-1,indicating that the NCO group was almost completely reacted.The self-made hydroxyalkyl silicone oil successfully capped IPDI;According to the analysis of 1H-NMR results,the peak at 6.34 ppm is attributed to the proton absorption peak of hydrogen on the N-H bond,indicating that the reaction was successfully carried out to generate the carbamate bond;13C-NMR analysis results show that the peak at 151.67 ppm belongs to the resonance absorption peak of carbonyl carbon linked to N-H bond,which indicates that the reaction has successfully generated carbamate bond,and these characterization means indicate that the synthetic product is silicone polyurethane.And through GPC analysis,it can be seen that the distribution of the obtained products is narrow and in a single distribution state.The viscosity of the synthesized silicone polyurethane increases with the increase of the molecular weight of hydroxyalkyl silicone oil,and its hydroxyl value is within a reasonable calculation error range compared to the theoretical hydroxyl value.(3)The above-mentioned graffiti-resistant additives with different molecular weights were added into a two-component polyurethane system to compound graffiti-resistant coatings.The test results show that when using organic silicon polyurethane with Mn 6583 and adding 1%,the additive has good compatibility with the resin.The cured coating has a hardness of 2H,adhesion of level 0,excellent anti-graffiti performance,and other physical properties meet the standard requirements of anti-graffiti coatings.TG analysis shows that the addition of organic silicon additives improves the heat resistance of the coating at the optimal dosage.SEM shows that the coating is flat and smooth at the optimal dosage.Compared with two similar types of additives available on the market,it can be seen that the self-made anti-graffiti additive composite anti-graffiti coating meets the performance requirements of anti-graffiti coatings on the market,and can be used as a qualified anti-graffiti additive in anti-graffiti coatings.Through the above work,a silicone anti graffiti additive containing active chemical groups has been synthesized,which has good anti graffiti effect when applied in paint systems,and the mechanical properties of the coating meet national standards,promoting the rapid and high-quality development of China’s paint industry.