UV Absorbers for the Improved Protection of Laminated or Overcoated Ink Jet Prints
Publication Date: 2003-Sep-12
The IP.com Prior Art Database
Laminates and clear top coats (overprint varnishes) containing UV absorbers of the hydroxyphenyl triazine class are advantageously used to protect ink jet graphics from fading caused by environmental factors such as moisture, pollutants and UV light.
UV Absorbers for the Improved Protection of Laminated or Overcoated
Ink Jet Prints
It has now been found that outstanding results in terms of image permanence can be obtained by implementing photostable triazine UVA having high extinction and broad absorption profiles across the long-wavelength ultraviolet region. UVA of this class are described, inter alia, in EP-A-434608, EP-A-531258, US-5489503, US-5462846, US- 5556973, US-5538840, WO 96/28431, US-6117997, US-6184375, US-6346619.
The ink jet recording material to which the laminate / overcoat is applied after printing has a customary base (for example polyethylene coated paper or plastic film) on which one or more functional coatings are applied for the purpose of e.g. absorbing the ink vehicle or receiving the image colorants. Uncoated recording materials (for example paper or vinyl) can likewise be employed; in this case, the recording medium functions simultaneously as base and ink receiver layer. Suitable material for ink jet printing is described, inter alia, in U.S. Pat. No. 5,037,448. The recording material is ink jet printed with inks that correspond to the utility. Such ink jet inks can be either aqueous or solvent borne and based on either dyes or pigments. Suitable ink jet ink formulations for printing on either coated or uncoated ink jet media are described, inter alia, in U.S. Pat. 5,098,477 and EP-A-672 538 (pages 3 to 6).
The ink jet printed recording material is laminated with a transparent film or overcoated with a transparent coating formulation containing 0.01-10 parts by weight of a hydroxyphenyl triazine, especially of below formulae (1) to (3), per 100 parts by weight of solid. The laminate film is typically based on a thermoplastic polymer. Examples of such polymers are described, inter alia, in US 6,284,821 (column 24 to 25). Suitable coating compositions comprise a film forming binder, especially one based on acrylic, alkyd, polyurethane, polyester or polyamide resin. The film forming binder can be cold-curable, heat curable or radiation curable, the addition of a curing catalyst possibly being advantageous. The coating composition can be applied to the printed ink jet recording material by the customary techniques, for example by spreading, spraying, flow coating or dipping. Suitable coating compositions, as well as usual application and curing techniques, are described in US 6,284,821 (columns 26 to 31) and in the publications cited therein.
Prints produced by other traditional or di...