The present invention relates to a process for producing a coating substrate by applying at least one coating composition to the substrate and then curing it to give a coating film on the substrate, to the coated substrates obtained by this process, and to a coating composition. The present invention provides a polyolefin microporous film formed from a polyolefin composition comprising a polyethylene, a first polypropylene having a viscosity average molecular weight of not less than 50,000 and less than 300,000, and a second polypropylene having a viscosity average molecular weight of not less than 300,000. Therefore, the opener beam is able to slide with respect to the fixed pin within the opener slot.