| The bonding composites parts of natural rubber and metal are widely used in vehicles,ships,aviation and other fields,due to the high elasticity,low temperature resistance,low heat generation.However,the non-polar characteristics of natural rubber limit its application in metal-to-rubber bonding.Although some adhesives produced by foreign companies can basically meet demand,such as LORD,HENKEL,and CILBOND,domestical adhesives have low bonding strength and are difficult to replace expensive foreign products.In addition,there are few papers and related patents on adhesives applied to metal and rubber bonding.To some extent,the research of adhesives which apply to metal and natural rubber has theoretical and practical values.This article has discussed and explored the shear strength and possible bonding mechanism of the modified adhesive,which mainly includes the following parts.(1)The orthogonal experimental design method was used to study the influence of the main components and the ratio of the phenolic resin to chloroprene rubber on the shear strength of 45# steel/natural rubber(S/NR).The results showed that the optimal content of silica,phenolic resin(PF)and chlorinated rubber(NCR)in resole/ neoprene(CP)adhesive were 4 phr,80 phr and 15 phr respectively.On the basis,the coupling agent type and KH550 content were researched.The results showed that γ-aminopropyl triethoxy silane(KH550)had the mostest significant effect on the shear strength compared with the other four coupling agents.With the increased of KH550 content,the shear strength of S/NR first increased and then decreased.When the content of KH550 was 22 phr,the maximum shear strength of CP adhesive was 4.74 MPa,but at this time the interface failure mode of the bonding parts did not reach the ideal state of the rubber substrate fracture.(2)The interface crosslinking agent ER was used to modify adhesive to improve the failure mode of S/NR parts.The effects of the ratio of ER to PF and the types of accelerators on the shear strength of S/NR were investigated.The results showed that the optimal content of PF to ER was 1:1.The shear strength reached the maximum when the accelerator Mg O/Zn O was added.In this ratio,the influence of KH550 modified adhesive on the shear strength of S/NR was further studied.The results showed that the shear strength was as high as 4.76 MPa when KH550 was 8 phr,and the failure mode of the bonding interface changed from the interface failure to the mixed failure of the rubber body and the interface.(3)In order to further improve the shear strength,the adhesives modified by KH550,ER and Mg O/Zn O were investigated.The influence of vulcanization temperature(150?180 ℃)on bonding properties of S/NR were discussed.The results showed that the bonding performance of CP adhesive modified by KH550 increased with the increase of temperature.When the temperature was 180 ℃,the maximum shear strength was 5.06 MPa.The shear strength of ERmodified CP adhesive improved by KH550 decrease with increase of temperature.However,the shear strength of ER-modified CR adhesives reinforced by Mg O/Zn O was not sensitive to temperature changes.Therefore,the suitable curing temperature of ER-modified adhesive was150 ℃,and that of KH550-modified CP adhesive was 180 ℃. |
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