Hello, yes i have found how to do this simply.
First, in IFTTT, creat a applet
In "This", use Weather underground Sunset
replace the "Fermeture-volet" by what you want, for exemple "close_blinds"
replace the 30 by the time you want in minute
replace the xxxxxxxxxxxxxx by your ifttt webhook key (if you don't know, search on you best friend ... google)
In "Methode" make "POST"
In "Content type" make "Application/x-www....."
Second in IFTTT, creat an other applet
In "This", use webhook with event name the same you write before, for exemple "Close_blinds"
In "That", use the service you use to close your roller shutter
And normaly, all is OK