Screening method using cured coating film properties

A method of screening coating material compositions for development of new coating formulations in the automotive field, said method comprising

• (1) providing a first coating material composition F1, the first coating material composition F1 comprising
• (i) at least one film-forming polymer P1, said polymer P1 having crosslinkable functional groups,
• (ii) at least one crosslinking agent CA1 having functional groups, which are reactive at least towards the crosslinkable functional groups of polymer P1,
• (iii) water and/or at least one organic solvent,
• (iv) optionally at least one phase compatibilizing polymer PMP,
• (v) optionally at least one additive A, and
• (vi) optionally at least one pigment PI1 and/or at least one filler FI1,
• wherein the constituents (i), (ii), (iii) and (iv) as well as (v) and (vi) each are different from one another,
• (2) applying the first coating material composition F1 onto at least one optionally pre-coated surface of a substrate to form a coating film on said surface of the substrate,
• (3) curing the coating film obtained after step (2) to form a cured coating film on the surface of the substrate,
• (4) measuring at least one property of the cured coating film obtained after step (3),
• (5) providing at least one further coating material composition being different from the first coating material composition F1 in precisely one or at most two parameter(s),
• wherein said parameter(s) are selected from the group consisting of (a) partial or full exchange of polymer P1 with a further polymer being different from polymer P1 and having crosslinkable functional groups being reactive at least towards the functional groups of crosslinking agent CA1, (b) partial or full exchange of crosslinking agent CA1 with a further crosslinking agent being different from crosslinking agent CA1 and having functional groups being reactive at least towards the crosslinkable functional groups of polymer P1, (c) lowering or increasing the amount of polymer P1 and/or of the polymer being different from polymer P1, which has been used for partial or full exchange of polymer P1 as defined in (a) in the further coating material composition, (d) lowering or increasing the amount of crosslinking agent CA1 and/or of the crosslinking agent being different from CA1, which has been used for partial or full exchange of CA1 as defined in (b) in the further coating material composition, (e) partial or full exchange of additive A if present with a further additive being different from additive A, and (f) lowering or increasing the amount of additive A if present and/or of the additive being different from additive A if present, which has been used for partial or full exchange of additive A as defined in (e) in the further coating material composition, (g) partial or full exchange of pigment PI1 and/or filler FI1 if present with a further pigment and/or filler being different from pigment PI1 and/or filler FI1, and (h) lowering or increasing the amount of pigment PI1 and/or filler FI1 if present and/or of the pigment and/or filler being different from pigment PI1 and/or filler FI1 if present, which has been used for partial or full exchange of pigment PI1 and/or filler FI1 as defined in (g) in the further coating material composition,
• (6) applying the further coating material composition onto at least one optionally pre-coated surface of a substrate to form a coating film on said surface of the substrate,
• (7) curing the coating film obtained after step (6) to form a cured coating film on the surface of the substrate,
• (8) measuring at least one property of the cured coating film obtained after step (7), said at least one property being the same property as measured in step (4),
• (9) optionally repeating steps (5) to (8) at least once, wherein each of the further coating compositions provided is different from one another and different from coating material composition F1,
• (10) incorporating the results of the properties measured in steps (4) and (8) and optionally of the results of the properties measured in case of an at least one-fold repetition as defined in step (9) into a database,
• (11) selecting at least one of the measured properties present in the database due to incorporation step (10),
• (12) evaluating and comparing the results of the at least one selected property of the cured coating films measured according to steps (4) and (8) and optionally after an at least one-fold repetition as defined in step (9) with each other, and
• (13) using the information obtained from evaluation and comparison step (12) for formulating and providing at least one new coating formulation being different from the first coating material composition F1 and from each of the further coating material compositions obtained after step (5) and from any coating material composition obtained optionally after an at least one-fold repetition as defined in step (9), wherein the at least one new coating formulation, when applied and cured as defined in steps (2) and (3), leads to a cured coating film showing an improvement of the at least one property selected in step (11), when measured as defined in step (4) and/or (8).