Preparation And Properties Of Silicone Tie-Coating

Silicone antifouling coatings are often used in conjunction with epoxy primers in shipbuilding industry.However,the silicone antifouling coatings may be damaged,cracked,and fallen off due to the poor adhesion between the two coatings during use,which cannot meet the requirements of the project.Regarding the problems above,the more mature solution is to connect the silicone antifouling coating with the epoxy primer by a tie-coating at present.In this paper,tie-coating was prepared by N-(2-aminoethyl)-3-aminopropyltrimethoxysilane(KH792)modified polydimethylsiloxane(PDMS)and epoxy resin modified PDMS respectively.The molecular structure,surface properties,surface morphology,mechanical properties and connection properties of the two coatings were investigated by experiments.Studies have shown that the tie-coating was prepared by a certain amount of silane coupling agent KH792 was introduced into the silicone resin PDMS through mechanical mixing has a good connection effect.Experiments show that the excellent interlaminar adhesion between the silicone antifouling coating and the silane coupling agent-modified silicone tie-coating,the effect of the addition of KH792 on the interlaminar adhesion between the tie-coating and the epoxy primer was investigated with great emphasis.The interlaminar adhesion between the tie-coating and the epoxy primer will improve with the increase of the KH792 content in the tie-coating,but excessive KH792 will cause the mechanical properties of the coating to decrease.The tie-coating has excellent mechanical properties and excellent interlaminar adhesion with epoxy primer when the KH792 content in the tie-coating is 2.21 wt.%,antispalling rate(APR)reaches 100%,and shear failure strength reaches 0.29 MPa.The anti-destructive ability of the coating was affected by film thickness of the tie-coating.When the film thickness reaches 119 μm,the anti-destructive ability of the tie-coating will be significantly improved.In addition,when the addition of KH792 is insufficient,the connection effect of KH792 will be affected by the curing temperature.The curing temperature was increased appropriately will improve the interlaminar adhesion between the epoxy primer and the tie-coating.The research on tie-coating was prepared by epoxy resin modified silicone resin shows that the elastic modulus of the coating increases,the elongation at fracture decreases,and the overall trend of fracture strength increases with the increase of epoxy resin content.This tie-coating is used in conjunction with epoxy primer and silicone antifouling topcoat.The tie-coating ES-30(the epoxy resin content is 26.3wt.%)shows good connection performance.The shear failure strength of matching coating system reaches0.37 MPa.The innovations of this article:(1)A certain amount of KH792 was introduced into PDMS through mechanical mixing,it is cross-linked and cured under the action of curing agent tetraethyl orthosilicate and catalyst dibutyltin dilaurate.The tie-coating was prepared in this way can achieve a good connection effect.(2)The epoxy resin was pretreated with KH792,and then the epoxy resin pretreatment product was physically blended with PDMS,it is cross-linked and cured under the action of curing agent tetraethyl orthosilicate and catalyst dibutyltin dilaurate.The epoxy modified silicone tie-coating was prepared in this way can achieve a good connection effect.