Radiation-curing resins

Photomer . [Harcros UK] Acrylic derivs. radiation-curing resins for inks, varnishes, glass lamination, oriented polypropylene film lamination, coatings fw plastics, blister pack adhesives. 

The use of radiation-curing resins, as described by Tran in Chapter 9, adds the most strength and stability to the artifact of any processes currently in use. The difficulty of access to y-ray sources and the lack of reversibility of the process have limited its use among conservators. 

Chem. Descrip. Hydroxyethyl acrylate CAS 818-61-1 EINECS/ELINCS 212-454-9 Uses Monomer for prod, of resins used in high performance coatings, pressure-sensitive adhesives and coatings for plastics and flexible substrates, radiation-cured resins, emulsion polymers and additives for personal care prods, and ion exchange resins Features Provides better adhesion, impact resist., flexibility and faster reactivity than methacrylate analogs Properties Colorless clear mobile liq. si. acrylic odor completely misc. with water, common org. soivs. dens. 1.101 g/ml vise. 8 cps (15.5 C) vapor pressure 0.1 mm Hg t.p. -30 C b.p. 192 C flash pt. (PMCC) 101.1 C 97.5% min. assay... 

Chem. Descrip. Hydroxypropyl acrylate CAS 25584-83-2 EINECS/ELINCS 247-118-0 Uses Monomer for prod, of resins used in high performance coatings, heat-cured topcoats, pressure-sensitive adhesives and coatings for plastics and other flexible substrates, radiation-cured resins Features Provides better adhesion, impact resist., flexibility and faster reactivity than methacrylate analogs... 

UV-radiation curing has become a well-accepted technology which has found numerous industrial applications because of its distinct advantages 1-3. One of its main characteristics is the rapidity of the process which transforms quasi-instantly the liquid resin into a solid polymer under intense illumination by a UV-source or a laser beam4. The polymerization rate can be finely controlled by acting on the initiation rate through the intensity of the UV radiation. It is... 

Dual-cure resins for wood composites. These resins (heat and EB irradiation systems) are based on urethane-acrylate thermoplastic adhesive demonstrate efficacy to bond wood. Eow amounfs of EB radiation were needed to produce a wood bond that survived shipping and that improved the composite modulus. The system demonstrated promise and a new direction for wood adhesives. 

The existence of two T2 relaxation times was also observed in the radiation cured photopolymers 99), and studies of tri- and tetra-functional network organosilicon polymers with rings at the network points 100). The effects of crystallization of poly-dimethylcarbosiloxane networks (PDMCS) I01), and water sorption and stoichio-metrical composition of the cured DGEBA/DETA resins on phase structure and mobility 102) were studied. 

Acrylic resins - [MAGNESIUMAND MAGNESIUM ALLOYS] (Vol 15) - [COATING PROCESSES - POWDER TECHNOLOGY] (Vol 6) -photocuring [RADIATION CURING] (Vol 20) -plasticization of [PLASTICIZERS] (Vol 19) -thiols m [THIOLS] (Vol 24)... 

There are basically two types of epoxy acrylate resins used in formulating adhesive systems. One is a vinyl ester resin that is used in two-component adhesive formulations much as a DGEB A epoxy or a polyester resin is. The other is a special type of resin that is used in radiation cure processes. This latter type of epoxy acrylate does not have any free epoxy groups, but reacts through its unsaturation. 

Epoxy acrylates are also commonly used as oligomers in radiation-curing coatings and adhesives. However, their name often leads to confusion. In most cases, these epoxy acrylates have no free epoxy groups left but react through their unsaturation. These resins are formulated with photoinitiators to cure via uv or electron beam (EB) radiation. The reaction mechanism is generally initiated by free radicals or by cations in a cationic photoinitiated system. The uv/EB cured epoxy formulations are discussed in Chap. 14. 

Radiation is used to crosslink (Fig. 14.2) or cure organic resins into durable coatings or adhesives having excellent physical properties with high chemical and temperature resistance. Radiation curing technology involves at least four considerations type of radiation... 

Radiation curing adhesives are generally applied as solvent-free liquids. High-solids EB and uv curing liquid adhesives have been formulated from a variety of resins and elastomers. They include epoxy acrylates, epoxies, other acrylates, polyesters, blends of acrylate monomers with elastomers, and other compositions. 

Pressure-sensitive adhesives are the essential components of adhesive tapes and labels. They are polymers with permanent tack, usually applied on substrates (plastic/metal films, siliconized papers). To enhance their tack, compounds with high inherent tack are added, for example, resins, plasticizers. Pressure-sensitive adhesives reach their adhesion on the material to be bonded by contact pressure, from which the term pressure-sensitive adhesive (PSA) derives. Apart from electron radiation, also UV-radiation curing described in Section 4.3.2 is applied in adhesive tape manufacturing. The monomer molecules to be polymerized are applied, in liquid form, to the substrates to be coated by rolling and are continuously cured to a polymer layer within seconds under a UV-radiation source. Depending on their composition, predetermined adhesion values can be adjusted. The adhesive tapes can be subsumed under the systems shown in Figure 5.4 ... 

Fefferman, G. B. "Using Ultraviolet Radiation Curable Resins for Printed Circuit Coatings", 2nd International Conference on Radiation Curing, Cincinnati, Ohio, May 1975. 

Gamma irradiation curing of epoxy resins for structural adhesives — Radiation cure polymerization of commercial diglycidyl ether of bisphenol F epoxy resin has been achieved using Co-60 irradiation source, compounding the monomer with and onium salt catalyst [9],... 

C. DISPENZA, F. SCRO, A. VALENZA, G. SPADARO, High energy radiation curing of resin systems for structural adhesives and composite applications , Rad. Phys. Chem., 63 (2002) 69-73... 

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