| 摘要 |
UV-curable compsns. comprises (on a solvent-free basis) 35-65 (pref. 40-60) wt.% of a first acrylated aliphatic urethane (I), 5-25 (pref. 10-20) wt.% of a second acrylated aliphatic urethane (II), 10-55 (pref. 10-30) wt.% of a multifunctional (m-f) acrylate (III), and (pref. 1-15, esp. 5-10) wt.% photopolymerisation initiator or sensitiser (IV). Opt. also present are hindered amine light stabiliser (HALS), antioxidant, and suitable solvent. (I) has mol.wt. 500-2000 (pref. 800-1000) and is the reaction prod. of a m-f acrylate with mol.wt. 190-500, contg. at least 3 polymerisable unsatd. gps. per molecule, and an aliphatic urethane prepolymer based on a polymer of allyl carbomonocycle diisocyanate and alkane polyolpolyacrylates. (II) has mol.wt. 1200-2600 (pref. 1500-2000) and is the reaction prod. of a multifunctional acrylate with mol.wt. 110-500, and an aliphatic urethane prepolymer with mol.wt. 800-2200, based on a polyether. (III) has mol.wt. 170-1000 and contains at least 2 polymerisable unsatd. gps. per molecule. Also claimed is a method for applying the compsn. to an article and irradiating to cure it, and the thereby top-coated prods., opt. incorporating an undercoat between the cured topcoat and substrate. Pref. (I) and (II) are selected from commerically available materials esp. `Ebercryl 8301' (RTM) and `AB 2010' (RTM) respectively. (III) acts as reactive diluent; trimethylolpropane triacrylate (TMPTA) and 1,6-hexanediol diacrylate (HDDA) are esp. pref. (IV) is a conventional material selected from e.g. aromatic ketones and benzoin ethers; 1-hydroxy-cyclohexyl phenyl ketone (IVa) is most pref. The HALS is used at 0.1-7.5 wt.%, pref. in combination with 0.1-7.5 wt.% of a benzotriazole light stabiliser (esp. a hydroxyphenyl benzotriazole (HPBT)), and 0.1-3.0 wt.% antioxidant. Suitable solvents include conventional esters, ketones, alcohols and aromatic hydrocarbons, comprising 40-60 wt.% of the total compsn. |
