| 摘要 |
The invention relates to thermosetting powder coating systems based on carboxyl-functional polyester resins, .beta.-hydroxyalkyl amides and/or polyepoxides and optionally, usual pigments, fillers and additives. The invention also relates to the production of said thermosetting powder coatin g systems and to their use, to protective layers consisting of these powder coating systems and to objects provided with protective layers of this type. The invention also relates to polyester resins that are suitable for formulating thermosetting powder coating systems. The polyester resins have an acid value of 15 to 70 mg KOH/g, a hydroxyl value of max. 10 mg KOH/g and a glass transition temperature of at least 35 ~C. These polyester resins conta in up to 80 mol % isophthalic acid in relation to the total quantity of all of the dicarboxylic acids used, and 0.5 to 30 mol %, in relation to the total quantity of all of the diols, pentanediol 1.5 and/or at least one pentanedio l 1.5 with at least one alkyl substituent and/or at least one 3-oxa-derivative of the aforementioned diols.
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