Surface veil and surface film integrated prepreg layer and processes for making the same

A method for producing a ready to use surface veil and surface film integrated prepreg layer, wherein the method is suitable to use in a production of lightweight structural parts/panels with class A surfaces, and the method comprises the following steps of:

• obtaining a curable bottom base resin formulation by mixing a curable bottom base resin, a first toughening agent, at least one accelerator, at least one curing agent and at least one hardener agent by heating the curable bottom base resin to 70° C. in a container while stirring by a mixer;
• coating a first release paper having an areal weight of 5 to 250 g/m2 with the curable bottom base resin formulation and obtaining a curable bottom base resin formulation coated release paper as a first resin film;
• impregnating the first resin film onto at least one side of a reinforcement fabric at a temperature in a range of from 40° C. to 110° C. to obtain a prepreg layer;
• obtaining the curable bottom base resin being 10% more viscous than a resin by dispersing a thermoplastic toughening agent in the curable bottom base resin by a mechanical mixer at 120° C. for 2 hours in a container;
• adding the at least one accelerator, the at least one curing agent and the at least one hardener agent to the curable bottom base resin being 10% more viscous than the resin and heating to 70° C. in the container while stirring by the mixer to obtain an outer resin formulation;
• coating a second release paper having an areal weight of 35 to 150 g/m2 with the outer resin formulation and obtaining an outer resin formulation coated release paper as a second resin film;
• impregnating the second resin film onto a surface veil having an areal weight of 35 to 150 g/m2 to obtain a second resin film impregnated surface veil;
• impregnating the second resin film impregnated surface veil onto at least one other side of the reinforcement fabric;
• and
• pressing the reinforcement fabric, impregnated by the first resin film on a first side, and the second resin film impregnated surface veil on a second side to obtain the surface veil and surface film integrated prepreg layer, wherein, in the obtained surface veil and surface film integrated prepreg layer, the reinforcement fabric is made of organic fibers and/or glass fibers and is at least partially resin free providing air venting paths.