rubber adhesion

I am working on a skim compound formulation for conveyor belts without the RFL-RFS system and it is polymer based. NR 60parts, Sbr1500
15parts and br 25 parts. Can anyone give me ideas on how to improve the adhesion ply to p[ly and cover to ply
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.