The major manufacturers have not changed their basic process in the last 20 years. Laminate sails are still built using yarns which are impregnated with resin and a scrim on both sides which is coated in resin to hold the membrane together. It is this resin that breaks down over time as the sail is hoisted, tacked and folded after racing or cruising. This causes delamination, the two sides of the membrane come apart and the sail loses structural strength as there is nothing to support the yarns in place. The resin also adds weight to the sail, initially this weight can be offset by the extra strength but as the resin breaks down the weight remains for less strength.
The M3™ technology doesn't need resin in the production of the sails and this has a number of advantages. When the yarns are impregnated with the resin and it sets, the yarns will become very hard in tension. As the sail moves and the yarns are bent and twisted, they will start to breakdown and the overall strength of the structure will be reduced. If the resin is removed, the yarns will remain soft, this means as the sail moves there is no difference in tension across the strand as the individual fibers that make up the strand can move independently. Removal of the extra yarns plus the significant mass of the resin in a laminate sail, results in a reduction in overall weight of at least 15-30%.
The M3™ skins are loaded into a vacuum bag which is pressurized to -0.95 bar, this equates to no less than 9 tons per square meter across the entire sail. The entire skin and bag is then loaded into a computer controlled oven. When the pressure and heat are applied to the sail the two layers of polymer react and fuse together to form a new layer of material in an irreversible process. This seals the two layers of Mylar together and encapsulates the structural threads. It is important to note that the polymer 'fuses' together and is not merely 'stuck' together, the resulting film is soft and flexible, delamination is not an issue anymore as there is no resin between the skins to break down over time. M3™ is a major advance from 'mould production' sail technology, which has demonstrated many limitations arising from: low temperature and a non uniform heating process acting on only one side of the sail (the main cause of delamination) and being physically limited in both size and shape of the 'one piece' sails because of the size and design of the mould.