Asymmetric multi-layer composites and processes for producing the same

A multi-layer composite comprising:

• (a) a first scratch-resistant coating layer;
• (b) a thermoplastic layer;
• and
• (c) a second scratch-resistant coating layer;
• wherein the first scratch-resistant coating layer and the second scratch-resistant coating layer are disposed on opposing sides of the thermoplastic layer;
• wherein the first scratch-resistant coating and the second scratch-resistant coating each comprise a primer layer having a thickness, and wherein the first coating and the second coating differ only in the thicknesses of their primer layers;
• and wherein the first scratch-resistant coating layer and the second scratch-resistant coating layer are selected such that a multi-layer composite having the first scratch-resistant layer disposed on both sides of the thermoplastic layer has a lower critical impact speed for tough/brittle transition at −30° C. according to DIN EN ISO 6603-1 than a multi-layer composite having the second scratch-resistant layer disposed on both sides of the thermoplastic layer.

A multi-layer composite comprising:

• (a) a first scratch-resistant coating layer;
• (b) a thermoplastic layer;
• and
• (c) a second scratch-resistant coating layer;
• wherein the first scratch-resistant coating layer and the second scratch-resistant coating layer are disposed on opposing sides of the thermoplastic layer;
• wherein the first scratch-resistant coating and the second scratch-resistant coating are not the same;
• wherein the first coating comprises:
• one or more compounds selected from the group consisting of UV curing coating systems based on acrylate, urethane acrylate or acrylosilane;
• photoinitiator;
• UV absorber;
• solvent;
• and optionally an inorganic finely divided compound;
• and wherein the first scratch-resistant coating layer and the second scratch-resistant coating layer axe selected such that a multi-layer composite having the first scratch-resistant layer disposed on both sides of the thermoplastic layer has a lower critical impact speed for tough/brittle transition at −30° C. according to DIN EN ISO 6603-1 than a multi-layer composite having the second scratch-resistant layer disposed on both sides of the thermoplastic layer.