All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
You are not allowed to delay the Prayer from its prescribed fixed time, as this is one of the greatest sins. So, you must repent from this and perform the Prayers at their prescribed fixed time. In fact, purifying oneself for the Prayer and praying a given Prayer does not take more than 10 to 15 minutes.
So, this can be done during lunchtime or even during work. If you cannot do so, then you must give up this work and look for a job where you can perform your religious duties. Allah Says (what means): {And whoever fears Allah —He will make for him a way out. And will provide for him from where he does not expect.} [Quran 65:2-3]
Allah knows best.