Ultraviolet-cured acrylates

E. Emmett, and J.R. Kaminski, Allergic contact dermatitis from acrylates in ultraviolet cured inks. J. Occup. Med. 19 113, 1977. 

Pekurovsky L.A. Capillary Forces and Stress Development in Drying Latex Coating. [LES] Wen M. 2000. Designing Ultraviolet-Curing of Multifunctional (Meth) Acrylate Hard Coats. [AVM, LES]... 

Ultraviolet curing grades of "aerobic" acrylic adhesives, however, have been developed to provide structural bonds within seconds at room temperature on a wide variety of substrates. Parts may be precisely positioned and then structurally joined "on demand" at a time convenient to the assembly process. 

Bjorkner B (1981) Sensitization capacity of acrylated prepolymers in ultraviolet curing inks tested in the guinea pig. Acta Derm Venereol 61 7... 

Nethercott JR, Jakubovic HR, Pilger C, et al (1982) Allergic contact dermatitis due to urethane acrylate in ultraviolet cured inks. Br J Ind Med 40 241... 

No cases of ACD or ICD or contact urticaria due to vinyl ester resins have been reported in the reinforced-plastics industry. There are relatively few published reports on contact allergy due to these compounds, despite their wide use in ultraviolet curable acrylic compounds, UV curing inks (Nethercott et al. 1983) and in DCRs (Kanerva et al. 1986 Kanerva et al. 1989). 

Anaerobic sealants Cyanoacrylates Ultraviolet-cured sealants Methyl methacrylate Metal and glass glues Epoxy diacrylates (vinyl resins) Acrylic dental bonding agents... 

FIGURE 8.3 Examples of monomers used in acrylic reaction adhesives, e.g. anaerobic and ultraviolet curing types. 

Ultraviolet Curing (Or UV Curing) n (1) Conversion of a wet coating or printing ink film to a soUd film by the use of ultraviolet radiation. (2) The process by which certain polymers or coatings are cured, with the aid of a photoinitiator, by exposure to ultraviolet radiation. One such polymer system is the oligomer tris(2-hydroxymethyl)isocyanurate triacrylate with an initiator and an acrylic monomer such as 2-phenoxyethyl acrylate in ratios from ten to 100 parts per 100 parts of the triacrylate (USP 4,812,489). 

Ultraviolet curing UV curing adhesives use ultraviolet light to initiate curing. This allows a permanent bond to develop without any need for heating. UV curable adhesives use various chemical systems, which include acrylics and acrylates, epoxies, polyurethanes (PUR), polyesters, silicones, vinyl and vinyl esters Aaylics are the most common components of UV curable adhesives. 

UVC Lacquer and Test. A white epoxy-acrylate lacquer was applied on all nickel plated sheets with different pretreatments to a thickness of 16 ym and was cured by irradiation with four 10-kW ultraviolet lamps for about 1.2 sec. 

Curing by light irradiation can be apphed to a variety of polymers. The acrylic family is a typical example of photosensitive monomers. A well-documented review has recently been dedicated to the curing of composites by ultraviolet radiation [45], Photocuring time is much shorter than for traditional thermal curing (minutes rather than hours), leading to a significant reduction in the cycle time. 

Pacansky et al. (1987) described the fabrication of dual-layer photoreceptors by radiation curing. The layers were coated with a polymerizable acrylate monomer or oligomer as the liquid component, then cured by a 175 kV electron beam or ultraviolet exposure. These methods were used for the preparation of generation layers containing bisazo and hydroxysquaraine pigments. 

Polyacrylate resins can be produced from EPOP by reacting them with acrylic acids. These resins can be applied on solid surfaces and when they are cured by ultraviolet irradiation, clear and glossy finishes result. The hardness and the tackiness can be increased or reduced by varying the amount and types of crosslinkers and the strength of the irradiation used (125-127). Characteristics of some polyacrylates based on epoxidized palm olein are listed in Table 48. 

The average shore A hardness of the cured sealant is 20 to 25 but increases with ageing. Resistance to ultraviolet radiation is excellent, but this is not important for indoor applications. The maximum movement accommodation factor (MAF) can be 15% of the total joint width. Joints should be designed so that movement due to shrinkage and thermal changes does not exceed the maximum MAF, related to the joint width. Table 5.4 lists the properties in general for acrylic emulsion sealants. These properties are summarised from the commercial literature of several acrylic emulsion sealant manufacturers and should not be considered as specifications. Table 5.5 lists the standard specifications for these sealants. 

In 1983, radiation curable 100 % solvent-free silicone acrylates were introduced into the market [4], This system provide the opportunity to be cured by either ultraviolet light (UV) or electron beam (EB). Similar in concept to peroxide initiation, silicone acrylate systems employ photoinitiators to generate free radicals and initiate cure, which is based on the polymerization of the acrylic C=C double bond via a radical chain reaction. 

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