Curable acrylate coatings

As an alternative to the above solutions, oxide glass overcladding with a phosphate jacket has been proposed for the so-called FLOX fibers (Vacha et al. 1987). Although diamond-like carbon (Stein et al. 1983, Tran et al. 1984) and other types of ceramic or metallic hermetic coatings have also been investigated, UV-curable acrylate coatings appear to be currently preferred for HMFG fibers such as those produced by Infrared Fiber Systems Inc., U.S.A. (IFS). 

During the past 15-20 years, the use of UV-curable acrylates in inks and coatings has increased tremendously. In the can-coating industry, UV-printing inks are used on beverage and beer cans as well as on crown caps and aerosol containers. UV-curable acrylate coatings are used as wood finishes, mat varnishes, parquet varnishes and sealers, and as varnishes and coatings in the manufacture of furniture (Bjorkner... 

A recent application of photopolymerization is the protection of the surface of optical components made of polycarbonate or acrylic resins. The surfaces of these parts are vulnerable to scratches and attack by chemicals. Coating of the surface with a thin layer (2-4 pm) of a UV-curable acrylic coating may increase the abrasion resistance and the chemical inertness considerably. 

Details of the US migration test procedures have been published [7-12]. A typical example of the application of a migration test procedure has been described by Lin and co-workers [13]. Migration studies were performed by determining acrylate monomers and oligomers in extractants from electron beam curable acrylate coatings. The cell extraction method used was that proposed by the FDA Centre for Food Safety and Applied Nutrition www.cfsan.fda.gov). Stainless steel extraction cells with Teflon spacers of 30 ml volume and 50 cm opening for the extraction solvent... 

These are another category of materials to the filler and pigment screens mentioned previously. These materials are generally organic and include derivitives of thiophen, benzotriazole and transition metal dithiocarbamates, e.g., Ferro 101, nickel dithiocarbamate. These substances are effective at concentrations of 0.1 % or less. UV curable acrylate coatings and inks have been used in the manufacture of printed polymer containers. 

Silicone release liners are used as a nonadhering surface to which adhesive materials, such as, for example, pressure-sensitive adhesives, can be laminated. UV curable release coatings are based on poly(dimethylsiloxane) oligomers functionalized with acrylate or epoxy groups and are mostly coated onto papers or thin films. 

To be suitable for radiation-curable powder coatings, materials must contain unsaturated double bonds. They may contain acrylic or methacrylic unsaturations, but nonacrylate systems can also be used.32 The latter are based on the same chemistry... 

The acrylate or methacrylate functional PIBs have also been used in UV-curable solventless coatings formulation in the presence of reactive diluents (multifunctional acrylate or methacrylate esters) and a UV-sensitizer [104]. The products were transparent, flexible films, with very little extractables, in which hard polyacrylate or polymethacrylate domains were dispersed in the soft PIB matrix. Tensile strength and ultimate elongation have also been obtained. 

UV curable waterborne coatings made of PU-acrylate ionomers have been synthesised and characterised by IR spectroscopy [93]. Similarly a series of novel PU ionomers with polydioxolane (PDXL) as soft segment is prepared and identified by FT-IR spectroscopy [94]. 

It has been demonstrated that the incorporation of this type of reactive fluorosurfactant into a radiation curable acrylic system provides for a high gloss coating due to wetting, flow and leveling attributes, but results also in increased stain resistance of the coating. 

A novel class of low-odouring and non-yellowing polymeric photoinitiators, based on side-chain hydroxyalkylphenone moieties, is reported [89-91] to be very active for UV curable clear acrylic coatings. Due to low volatility and affinity for the organic phase, these photoinitiators are also claimed to be very effective in the curing of water-based acrylic emulsions in which water must be evaporated before the exposure to UV light. These commercial polymeric systems (KIP) are prepared by functionalization of a-methylstyrene prepolymers. 

Segurola, J. Allen, N. S. Edge, M. Me Mahon, A., Design of eutectic photoinitiator blends for UV/visible curable acrylated printing inks and coatings, Prog. Org. Coat. 1999,37, 23-37. 

These dual UV/thermally curable conformal coatings are based on the ability to rapidly transform a liquid composition into a cross-linked solid by the free-radical polymerization of a polyfunctional acrylate in the presence of a low concentration of a polyfunctional thiol (1). Under these conditions, the polythiol functions partly by adding across the acrylic double bond and partly as a chain transfer agent in the acrylate homopolymeriza-... 

Radiation-Curable Polyester Coatings. Radiation-curable polyester paints (see also Section 3.7) are particularly suitable for coating flat surfaces (strips, boards, sheets) and for temperature-sensitive substrates (paper, plastics). Acrylate-modified polyester resins are used for UV printing inks, UV varnishes for paper and plastics, as well as for pigmentable, electron beam-curable gloss and matt paints [2.86]. Radiation-curable polyester paints are also suitable for metal coatings with good elasticity. 

Chem. Descrip. Aromatic urethane aciylate oligomer Uses Urethane-acrylic tor UV-curable metal coatings, plastic coatings, inks... 

Chem. Descrip. Polyester acrylate oligomer Uses Polyester-acrylic for UV-curable wood coatings, flooring Features Exc. hardness, abrasion resist. good chem. resist. fast cure Properties APHA 60 color dens. 9.5 Ib/gal vise. 1800 cps (60 C) CN2258 [Sartomer]... 

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