Quick PHP Fix

Hello, I have a php script that runs and send report to an email address that we enter on front-end. Right now the issue is that the email gets sent instantly to the email address. I just want to put a delay of 40 minutes to it. In other words, instead of instant emailing, I want the script to send the same email (contains unique information) after 40 mins of the time when the script is run. Please advise me regarding the delay function in script. Note: It's not about cron because every email is unique and I just need the email to go a little bit late. Thanks