Export Progress Button

I created this export progress button for a financial dashboard. Users need to export financial documents. Generating these files takes some time - a couple of seconds. The goal was to inform the user about this and preventing him requesting the export multiple times.

The button is hand coded with CSS3 and vanilla javascript. The GIF that you are seeing here is not representative when it comes to timing. Therefore you should try out the button at CodePen (http://codepen.io/lorenzvs/pen/fdEFr).

I'm interested in feedback on typography and animation.