In addition to access to markets and natural resources, another reason for europe's interest in dominating africa and asia was to

Trade and Power were the main reason for European interest in Asia and Africa.

Specificly to gain new land, people to work on their land and do other hard labor and collect natural resources for metals, minerals and spices. 
Only Belgium, France, Germany, Italy, the Netherlands, Portugal the United Kingdom and Spain obtained land in Asia and Africa, no Eastern European countries obtained any colonies outside Europe and neither did Greece or any country in Scandinavia, so just a few countries possessed 95% of the worlds surface during the colonial days, divided between 8 countries which sold, traded and stole colonies off of each other during that period.

Mining manufacturing