If each student travels with 5 others, then groups are made up of 5 + 1 = <<5+1=6>>6 students.
This means there are a total of 5 groups * 6 students = <<5*6=30>>30 students in the class.
Each student needs 2 sandwiches, which means the teacher will make 30 students * 2 sandwiches per student= <<30*2=60>>60 sandwiches in total.
Therefore, the teachers will need 60 sandwiches * 2 pieces of bread per sandwich= <<60*2=120>>120 pieces of bread.
#### 120