Cure, acrylic resins

Lai, C.P., Tsai, M.H., Chen, M., Chang, H.S., and Tay, H.H., Morphology and properties of denture acrylic resins cured by microwave energy and conventional water bath, Dental Mater., 2004, 20, 133. 

Urethane-acrylate resin curing agent, paints Ancamide 801 Ancamide 802 Ethyl octynot PEG-3 trimethylolpropane triacrylate SR 351 SR 399 SR 454 curing agerV, paper dear coats Epoxy acrylate... 

Urethane-acrylate resin curing agent, paints Ethyl octynol... 

The GMA clear coatings have outstanding exterior durability, hence their acceptance in the automotive sector (see Fig. 2). Pigmented GMA acrylic powders have not foimd widespread use in market areas other than automotive, eg, architectural applications. Hydroxyl functional acrylic resins cured with blocked isocyanates or uretdione-based curatives have also found use in automotive applications and their exterior durability is only somewhat less than that of the GMA acrylic powders (50). Carboxyl functional acrylic resins are also commercially available. They can be cured with TGIC for exterior applications or with bisphenol A epoxy resins. The latter combinations are sometimes called acrylic-epoxy hybrid coating powders and are noted for their excellent hardness, stain, and chemical resistance. They find use primarily in appliance coatings (79). 

Polyurethane acrylate resins cured by two different methods, thermally and photochemically, are investigated by means of differential scanning calorimetry and thermally stimulated depolarisation currents. Even if both curing methods lead to the same material from a chemical point of view, important differences exist between the thermocured resin and the photocured resin in terms of molecular relaxation behaviour. 8 refs. 

Studies of the particle—epoxy interface and particle composition have been helphil in understanding the mbber-particle formation in epoxy resins (306). Based on extensive dynamic mechanical studies of epoxy resin cure, a mechanism was proposed for the development of a heterophase morphology in mbber-modifted epoxy resins (307). Other functionalized mbbers, such as amine-terminated butadiene—acrylonitrile copolymers (308) and -butyl acrylate—acryhc acid copolymers (309), have been used for toughening epoxy resins. 

Table 3 lists the selected properties [16] that we have measured for several commercially available acrylate resins manufactured by the Sartomer Company and the Rohm and Haas Company. The resins were cured in an AECL Gammacell Model 240. The temperature rise was measured for an 8-g sample using Acsion s (formerly AECL Radiation Applications Branch) Gamma Calorimetry method [17]. All of this information is being used to evaluate the applicability of EB-cured acrylate adhesives for repairing composite structures. Combinations of these adhesives can be used to create electron-curable adhesives suitable for composite repair. 

Electron-cured panel Hercules AS4, 5HS, 6K fiber, FW3 epoxy acrylate resin. 

These requirements are usually met with two-pack paints based on hydroxyl-rich polyester or acrylic resins in the pigmented pack and aliphatic polyisocyanates in the activator pack. Cure with this type of finish is relatively fast and complete even at low ambient temperatures. An alternative finish is an acrylic lacquer, similar to the lacquer used for refinishing motor cars. These finishes are applied to the assembled aircraft by operators protected by air-fed hoods and using airless or conventional spray guns. High durability pigments are included. 

Unsaturated polyester finishes of this type do not need to be stoved to effect crosslinking, but will cure at room temperature once a suitable peroxide initiator cobalt salt activator are added. The system then has a finite pot life and needs to be applied soon after mixing. Such a system is an example of a two-pack system. That is the finish is supplied in two packages to be mixed shortly before use, with obvious limitations. However, polymerisation can also be induced by ultra violet radiation or electron beam exposure when polymerisation occurs almost instantaneously. These techniques are used widely in packaging, particularly cans, for which many other unsaturated polymers, such as unsaturated acrylic resins have been devised. 

Transparent PVC plates were coated with a 70 pm thick film of an epoxy-acrylate resin containing 0.5 % of a benzotriazole UV absorber. They were first UV cured for one second and then exposed at 40°C to the low intensity radiations of a QUV accelerated weathering tester. The extent of the degradation was followed by Invisible spectroscopy, a very sensitive method that permits detec-... 

S02-cured epoxy resin. Modified epoxy/acrylic resins (1.2 to 1.4% of sand weight) are mixed with organic peroxide (26 to 60% of resin weight), the mixture is blown into the core box and a hardening mechanism similar to the S02 process takes place. 

An obvious means of increasing conductivity is to incorporate metals into the fabric. Thus fabric can be sprayed with a liquid resembling metallic paint, containing micron-sized metallic particles such as copper incorporated into a binder such as a polyester, epoxy or acrylic resin. During curing the metallic particles come into contact with one another, thus... 

The developmenf of self-curing resins, i.e., systems curing without photoinitiators or, in some cases, with just small amounts of photoinitiators, has been reported recently. Such resins are synthesized by Michael reaction of acrylic functional materials with Michael donor compounds such as acetoacetates. The resulting product has an increased molecular weight compared to the parent acrylate(s). This provides resins with reduced volatility and propensity for skin absorpfion. This new technology is versatile and flexible and opens a possibility of synfhesis of a large number of different acrylate resins. The novel resins reportedly exhibit unique depth of cure capability. In the absence of a photoinitiator (PI), film of approximately 10 mils (0.25 mm) thick can be cured at a line speed of 100 fpm (30.5 m/min). When only 1% of PI is added, the thickness of film that can be cured increases to over 100 mils (2.5 mm). 

Schafffing, O.G. (1976) Composition comprising epoxy resin, copolymer of butadiene and acrylic acid, curing agent... 

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)... 

Irradiation by Ultra-Violet or Visible Light. Systems of this nature comprise materials such as acrylic resins in which a photo-sensitizer (for example, benzophenone) is incorporated. On exposure to ultra-violet radiation the photo-sensitizer dissociates into free radicals which then catalyse polymerization of the acrylic material. The reaction is controllable and takes place within a few seconds the ultra-violet radiation may be directed and focused so as to obtain cure precisely where needed. Products like these are used to retain coatings, wiring, and other components in the assembly of electronic goods. 

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. 

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