Reference

Crosslinking agents for epoxy resins

Crosslinking agents for epoxy resins. Brandt, Siegfried; Schmitt, Felix; Wolf, Elmar (Veba-Chemie A.-G., Ger.). Ger. Offen. DE 2640408 9 Mar 1978, 15 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C08L063-00. APPLICATION: DE 76-2640408 8 Sep 1976. DOCUMENT TYPE: Patent CA Section: 42 (Coatings, Inks, and Related Products) 4-Amino-2,2,6,6-tetramethylpiperidine (I) [36768-62-4] is a crosslinking agent for epoxy coatings and moldings with good storage stability and low toxicity. Thus, a mixt. of 570 parts bisphenol A epoxy resin and 156 parts I is coated on sheet metal at 80° and baked 10 min at 180° to give a coating with thickness 35-40 m, Koenig pendulum hardness 214 s, Sward hardness 30, crosscut adhesion 0, Erichsen indentation 10.2 mm, and Gardner impact strength 70 in.-lb.

Hardeners for epoxy resin moldings and coatings

Hardeners for epoxy resin moldings and coatings. Brandt, Siegfried; Wolf, Elmar (Veba-Chemie A.-G., Ger.). Ger. Offen. DE 2640409 9 Mar 1978, 15 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C08G059-44. APPLICATION: DE 76-2640409 8 Sep 1976. DOCUMENT TYPE: Patent CA Section: 36 (Plastics Manufacture and Processing) Section cross-reference(s): 27 The hardeners were prepd. by the reaction of 2 mol 4-amino-2,2,6,6-tetramethylpiperidine [36768-62-4] with 1 mol urea [57-13-6] or isophorone diisocyanate [4098-71-9]. Mixts. of the hardeners with epoxy resins had a long shelf life and hardened during heating to prep. moldings and coatings. Thus, 10 parts 1,3-bis(2,2,6,6-tetramethyl-4-piperidyl)urea [34402-56-7] was mixed with 90 parts glycidyl ether of bisphenol A at 80° to prep. a mixt. which had gel time 300 s at 200°, did not harden during 24 h at 50°, and hardened during 10 min at 200° to give a hard, transparent, solvent-resistant molding with smooth surfaces.