Preparation And Wear Resistance Of UV Curable Organic Inorganic Hybrid Coatings

UV-curable coatings have the advantages of efficient,energy-saving,economical,environmental-friendly,and enabling,and are widely applied on the substrate surfaces such as wood,metal,paper,and plastics etc.However,external effects on the coatings can cause wear and scratch damage.These abrasions can cause loss of gloss,loss of adhesion,or even complete destruction of the coatings.Adding inorganic fillers to UV-curable coatings can improve the wear resistance of the coatings,but there are two accompanying problems.On the one hand,the dispersion of inorganic fillers in organic resins is poor,and on the other hand,the inherent physical and chemical properties of inorganic fillers can have a negative impact on other properties of the coatings.In response to the above issues,in order to improve the wear resistance of UV-curable organic inorganic hybrid coatings,three inorganic fillers are selected in this research,that is Si O₂ nanoparticles,montmorillonite,and potassium titanate whiskers,to improve their dispersion in the coatings through organic modification and optimization of addition methods.The impact of these three inorganic fillers on the wear resistance of UV-curable coatings and other coatings properties were explored.The specific research content and results are as follows:（1）In this chapter,silane coupling agent KH570 is used to modify the surface of Si O₂nanoparticles to improve their dispersibility in UV-curable coatings and to enhance the hardness and wear resistance of UV-curable coatings.The effects of the addition method and modification degree of Si O₂ nanoparticles on dispersion were systematically investigated,and the effects of the addition of Si O₂ nanoparticles on the wear resistance of UV-curable coatings and the properties of other coatings were studied.The results show that the addition of Si O₂nanoparticles/active diluent dispersion can improve the dispersion of Si O₂ nanoparticles in the coatings,and the dispersion gradually improves as the degree of modification increases.In addition,after the addition of Si O₂ nanoparticles,the double bond conversion of the coatings remains at 70%,the UV curing rate remains basically unchanged,and the coatings have good settling resistance with improved thermal stability.When the addition of Si O₂ nanoparticles reaches 10 wt%,the pencil hardness of the coatings is increased from B to F,and the mass loss of the coatings after wear is decreased by 12.3 mg.However,the adhesion of the coatings is decreased from 0 to 5,the T-bend grade is decreased from 0 T to 5 T,and the impact strength is decreased by 8.3 J.（2）In view of the fact that the addition of modified Si O₂ nanoparticles in the previous chapter will lead to the decline of some properties of the coatings.In this chapter,cationic surfactants with methacrylate groups,methacrylic acid,and（3-aminopropyl）triethoxysilane are used to conduct multiple modification treatments on montmorillonite（MMT）to improve its dispersion in the coatings.By grafting polar groups onto its surface,a“bridge”structure of“substrate MMT resin matrix”is formed to improve the adhesion of the coatings to metal substrates.The effects of modified MMT on coatings properties were systematically studied.The results show that the double bond conversion of the coatings remains at 70%,the UV curing rate is almost unchanged and the coatings have good settling resistance after MMT addition.When the addition amount of modified MMT reaches 10 wt%,the wear mass loss of the coatings is reduced by 9 mg compared to the coatings without MMT,the pull-off adhesion is increased by 0.96 MPa,the pencil hardness of the coatings is increased from B to HB,the T-bend grade is decreased from 0 T to 2 T,and the impact strength is decreased by 5.3 J.（3）Given that the introduction of modified MMT in the previous chapter can reduce the negative impact of inorganic fillers on coating performance.In this chapter,sodium metaaluminate and sodium silicate are used to precipitate a layer of Al₂O₃ and Si O₂ particles on the surface of potassium titanate whiskers（PTW）through uniform precipitation method,and then silane coupling agent KH570 is used for organic modification to improve their dispersion in UV-curable coatings.The effects of precipitation of Al₂O₃ and Si O₂ particles on the amount of KH570 grafted onto the surface of PTW were compared.The effects of modification degree and addition method on the dispersion of PTW in the coatings were discussed.The effects of modified PTW on the wear resistance of UV-curable coatings and the properties of other coatings were systematically investigated.The results show that surface precipitation of Al₂O₃can graft more KH570 onto the surface of PTW,and with higher grafting rate of KH570,the better the dispersion can be achieved.The addition method of PTW/active diluent dispersion can improve the dispersion.After adding modified PTW,the double bond conversion and curing rate of the coatings are decreased but did not affect the actual gel content.When the amount of modified PTW reaches 5 wt%,the pencil hardness of the coatings is increased from B to HB compared to the coatings without PTW,the scratch adhesion remains at level 0,the T-bend level remains at 0 T,and the impact strength also remains at 9.6 J.The mass loss after wear is reduced by 10.6 mg.