Acrylated epoxy oligomer

Polyhydroxyurethane polymer usually has poor water resistance due to plurality of hydroxyl groups, but it is possible to prepare water-resistant materials in some formulations. For example, a cyclocarbonate acrylic was applied on a base of acrylic epoxy oligomer and a polymer was prepared with high water and weather stabilities... 

The adhesive formulation used In this study was comprised of a mixture of acrylated epoxy oligomers and diluent acrylate and vinyl monomers. 

When acrylated epoxy resins are used, the oligomers may simply be reaction products of the diglycidyl ether of Bisphenol A, or one of its higher analogs, with acrylic or methacrylic acids. The preparation of a typical acrylated epoxy oligomer can be illustrated as follows ... 

Of the commercially available EB-curable adhesives [9-12], the resins fall within one of two categories based on their curing mechanisms. The majority of EB-curable resins are based on (meth)acrylate-functionalized oligomers involving a free-radical curing mechanism. The second category is the epoxy resins that cure by a cationic mechanism. 

Reactive prepolymers used as binders are produced by acrylation of oligomers, such as epoxy resins, urethanes, polyesters, silicones, oligo-buta-diene, melamine derivatives, cellulose, and starches. Prepolymers are the principal ingredients of coating formulations and largely determine the basic properties of the coating. Examples of industrially important acrylated prepolymers are in Table 5.9. 

Epoxy acrylates. The most widely used oligomers are aromatic and aliphatic epoxy acrylates. Epoxy acrylates are highly reactive and produce hard and chemically resistant films. The polymerization of monoacrylates produces linear polymers,... 

Acrylated oligomers can be divided into three main classes polyester acrylates, epoxy acrylates, and urethane acrylates. Urethane acrylates are an especially important commercial class of oligomers. Applications Include binders for magnetic media, vehicles for inks, and coatings for vinyl floor tiles, optical fibers, and paper. Each application has certain performance requirements that must be met by the urethane oligomer. This paper will discuss the effect of urethane acrylate composition on end properties. 

The main reason for the limited industrial application of radiation-induced cationic polymerization is that oligomers that offer high cure rates are not commercially available. So far, due to their excellent combination of chemical, physical and electrical properties, only multifunctional epoxy oligomers have been used, but these have poor cure speeds compared to acrylate based systems. This is a serious limitation. Interesting alternatives to the epoxys are oligomers based on highly reactive vinyl ethers (21. 22) and the recently developed distsrrene ethers (23). which are as reactive as vinyl... 

Prepolymers. A broad range of acrylated resins (oligomers) are commercially available. The film-forming properties depend on the oligomer system. One of the most common is the acrylated epoxy system. In acrylated urethanes, an isocyanate-functional prepolymer with a polyol backbone can be reacted with a hydroxy-functional monomer (e.g., hydroxyethyl or hydroxypropyl acrylate). Many different resins can be synthesized by varying the polyol backbone, the isocyanate type, and the hydroxy-functional monomer. Polyester acrylates are another example of commercially important prepolymers. Acrylated acrylics have an acrylic backbone with pendant acrylate functionality. 

Figure 8.7 shows that the conversion of monomers in photopolymerization of PMMA-acrylate increases with the amount of the plasticizer. Polymerization rate and conversion are affected by plasticizer. Figure 8.8 shows more complex behavior attributed to cure of epoxy oligomers. With very small additions of plasticizer (up to 1%) cure rate increases. This may be explained by decreasing the activation energy due to formation of complexes. Further increase in plasticizer concentration reduces rate because of dilution effect and complexing with proton donors which inhibits reaction. Comparison of results shows that addition of a plasticizer is more complex, as commonly thought, than the simple reduction in viscosity by addition of inert liquid. 

Henriks-Eckerman M-L, Kanerva L (1997) Product analysis of acrylic resins compared to information given in material safety data sheets. Contact Dermatitis 36 164-165 Henriks-Eckerman M-L, Laijoki T (1986a) Aliphatic polyamines and epoxy oligomers in cold cured epoxy products (in Finnish with English summary). Tyoterveyslaitoksen tut-kimuksia 4 37-40 (summary p 69)... 

Acrylated epoxies comprise one of the largest classes of UV/EB oligomers. These resins were described in patents as early as 1968 (91. Originally developed for thermal cure applications, the diacrylate of the diglycidyl ether of bisphenol A, remains the largest volume oligomer of this class used today. Acrylated epoxies were much faster curing than... 

The main components of UV/EB-cured adhesives are reactive oligomers which contribute adhesion, toughness, and flexibility to the overall properties of UV/EB adhesives. Typical reactive oligomers include acrylated epoxy resins and aromatic urethanes. 

Commercial acrylate oligomers are available that have a wide range of chemistries, functional group (acrylate) content, and viscosity. Among the most commonly used oligomers are difunctional polyester acrylates, epoxy acrylates, polyurethane acrylate and polyether acrylates. The chemical structures of oligomers control such properties as viscosity, reactivity, and thermo-mechanical properties of cured films. For example, epoxy esters produce much harder films compared to polyether acrylate of comparable... 

Radiation cure coatings are typically solvent-free, high sohds systems based on acrylated epoxy or urethane oligomers and diluent multifunctional acrylate monomers. Since radiation intensity varies significantly with... 

A second type of uv curing chemistry is used, employing cationic curing as opposed to free-radical polymerization. This technology uses vinyl ethers and epoxy resins for the oligomers, reactive resins, and monomers. The initiators form Lewis acids upon absorption of the uv energy and the acid causes cationic polymerization. Although this chemistry has improved adhesion and flexibility and offers lower viscosity compared to the typical acrylate system, the cationic chemistry is very sensitive to humidity conditions and amine contamination. Both chemistries are used commercially. 

Unsaturated acrylic oligomers are made from unsaturated acrylic monomers. For example, an epoxy acrylate may be made by reaction of acrylic acid with epoxy resin. 

This rationale is evident also in other bromine-containing oligomers, for example those based on brominated epoxy resins (20) and on poly-pentabromobenzyl acrylates (21). 

Oligomers and Resins. Oligomers and resins used were Ebecryl 3700 epoxy acrylate, Radcure Specialties, Inc., Smyrna, GA 30080 Unicarb, which is 73% UVR 6128 (a cycloaliphatic epoxy), 26.5% polyol and 0.5% Silwet L-7602 (See under miscellaneous compounds), Union Carbide Chemicals and Plastics Co., Inc., Danbury, CT 06817-0001 and Heloxy 505 Modifier, Shell Chemical Co., Houston, TX 77210. 

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