You nailed it when you said, "I'm employee". During my career I got confused a few times about my role and thought my status was more important that it was. You either start something or work for the someone who started something (or in rare cases you are a genius the company relies on).

I would speculate that if you say you are leaving you will be offered a pay increase. However there is a risk playing the leave card. Some managers will start thinking about your replacement, even if you stay.

In my experience though founders think their company is the best thing since sliced bread and don't like people to leave. So be bold if you can afford to lose the job.