Radiation-curable

Solution polymers are the second most important use for acryflc monomers, accounting for about 12% of the monomer consumption. The major end use for these polymers is in coatings, primarily industrial finishes. Other uses of acryflc monomers include graft copolymers, suspension polymers, and radiation curable inks and coatings. 

Examples of typical radiation curable polymer systems, experimental conditions, and appHcations are Hsted in Table 5. 

Polymers. The molecular weights of polymers used in high energy electron radiation-curable coating systems are ca 1,000—25,000 and the polymers usually contain acryUc, methacrylic, or fumaric vinyl unsaturation along or attached to the polymer backbone (4,48). Aromatic or aUphatic diisocyanates react with glycols or alcohol-terrninated polyether or polyester to form either isocyanate or hydroxyl functional polyurethane intermediates. The isocyanate functional polyurethane intermediates react with hydroxyl functional polyurethane and with acryUc or methacrylic acids to form reactive p olyurethanes. 

Fig. 10. Generalized formulation design outline for radiation-curable coatings and adhesive systems. The cross-linker is a multifimctional unsaturated cross-linking agent or oligomer, rj = viscosity CR = cure rate S = shrinl ge H = hardness F = flexibility A = adhesion 7 = surface energy ...

The majority of the commercial radiation-curable coating systems (high energy electron and light-cured coating systems) are clear or contain siflca... 

R. P. Eckberg, "Chemistry and Technology of Radiation Curable Sihcone Release Coatings," in D. Satas, ed.,Mdpances in Pressure Sensitive A.dhesives, Satas Associates, Warwick, R.I., 1992. 

While the chemistry of radiation curable hot melt adhesives is the same as that used in liquid (syrup) adhesives and coatings discussed elsewhere in this volume, there is a fundamental difference between the objectives of reaction in the two types of systems. Syrups consist largely or entirely of reactive monomeric and/or oligomeric materials. Radiation is used to initiate the polymerization of virtually the entire mass. In contrast, hot melts generally contain polymers initially, and these polymers are capable of reaction via radiation to produce chain extension and... 

One key consideration in developing radiation curable adhesive systems is the thermal stability and volatility of any photoinitiators used. These chemicals are designed for liquid systems where these issues do not arise. Few of the commercial photoinitiators have adequate thermal stability at the highest hot melt temperatures (180-200°C) and many are too volatile. Reduced application temperatures and special antioxidant packages are often required. 

Woods, J.G., Radiation-curable adhesives. In Pappas, S.P. (Ed.), Radiation Curing, Science and Technology. Plenum Press, New York, 1992. 

NR, styrene-butadiene mbber (SBR), polybutadiene rubber, nitrile mbber, acrylic copolymer, ethylene-vinyl acetate (EVA) copolymer, and A-B-A type block copolymer with conjugated dienes have been used to prepare pressure-sensitive adhesives by EB radiation [116-126]. It is not necessary to heat up the sample to join the elastomeric joints. This has only been possible due to cross-linking procedure by EB irradiation [127]. Polyfunctional acrylates, tackifier resin, and other additives have also been used to improve adhesive properties. Sasaki et al. [128] have studied the EB radiation-curable pressure-sensitive adhesives from dimer acid-based polyester urethane diacrylate with various methacrylate monomers. Acrylamide has been polymerized in the intercalation space of montmorillonite using an EB. The polymerization condition has been studied using a statistical method. The product shows a good water adsorption and retention capacity [129]. 

The purpose of work described here is to develop a coating which can be used on naval vessels for touch up purposes while a ship is underway. Radiation curable coatings are of special interest because of the extremely low level of volatile organic compounds emitted during curing. To be useful the coating should be Navy gray and suitable for application to cold surfaces. When used in confined spaces a further limitation is that the application should not produce ozone and for some Naval applications mercury is not... 

VDC polymer degradation via, 25 713 Radiation-curable coatings, 10 442 liquid, 10 438... 

Radiation-curable epoxy acrylates, 10 450 Radiation cures, silicone network preparation via, 22 567-569 Radiation curing coatings, 7 133-135 of printing inks, 14 314 Radiation damage, ion implantation and, 14 435-436 Radiation drying coatings, 7 29-30 Radiation effects... 

The effect of environmental concerns on future developments in the paint industry is discussed. Particular attention is paid to volatile organic compound regulations, developments in powder coatings, and radiation-curable coatings. Tabulated information is presented on applications, backbone type and typical mechanical properties of Incorez W830 series PU dispersions and Incorez W2000 series uiethane/aciylic hybrids. 10 refs. EUROPEAN COMMUNITY EUROPEAN UNION UK WESTERN EUROPE... 

V-PYROL/RC Vinyl Pyrrolidone Radiation-Curable Grade for Coating Systems", Technical Bulletin 2302-081R, GAP Corporation, New York, 1970. 

Solid urethane and polyester acrylates may be used as main components of radiation curable powders. Together with suitable unsaturated polyesters, powders are formed, which give low-film-flow temperatures and allow separating of film formation from curing. This technology has been used successfully in powder coating of wood and plastics. ... 

Screen printing of UV inks is being done over paper, metal, films, foils, plastics, and PVC. Radiation curable materials are being used as vehicles for ceramic inks that are screened onto automotive windshields, cured, and then fired in an oven to bum off the organic binder and fuse the ceramic into the glass windshield. ... 

Smart cards in the form of SIM cards for mobile (cell) telephones contain chip modules, and UV radiation curable epoxies have been shown to offer advanfages in fhe encapsulation of these vital components. ... 

Optical fibers are widely used in the telecommunication industry for fhe fransmission of digital pulses of voice, video, and dafa. In order to keep losses in signal strength at a minimum, the fiber (usually a doped silica glass) has to be coated with a material of lower refractive index than its own refractive index. This layer is protected by a "buffer," which acts as a cushion. The buffer is encased in one or more protective layers (see Figure 7.18). Both the primary and protective coatings are very often UV radiation curable. 

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