Here it is, straight from a manufacturer "ad" Not sure how pressure applied is "Vacuum". They all fail if not cared for properly.
ComposiTek composites are vacuum laminated onto a structural frame of double-welded aluminum. This vacuum-lamination process creates one-piece, seamless, rigid walls, floors and roof for less flex and sway down the road. ComposiTek construction results in a stronger, stiffer trailer with the durability and weight distribution only found in monocoque aeronautical engineering.
In the vacuum bonding process the entire structure is placed in a giant vacuum bag and pressurized to approximately 129 pounds per square inch. The wall remains in the bag, under pressure, for 20 to 40 minutes to allow the resins and adhesives to become one piece. This process uses more advanced technology that is significantly more expensive than conventional pinch rolling, but the result is the finest construction available in the RV industry today.
Lesser manufacturers claim “laminated” or “bonded” construction, but unless it is “vacuum bonded” it is probably “pinch-rolled laminated”—an inferior process where the wall goes through two large rollers squeezing the glue as it “pinches” the pieces together. The vacuum process allows for even pressure at a high pounds per square inch rate over a much longer period of time for a superior bonded seal.