UV-curable acrylate resins

Oxo-l,3-dioxolan-4-yl methyl L CHj-O-C-CI 23385-72-0 0 v° Dec. UV curable acrylic resins Hydro gels Blowing agents for plastic foams Foods additives... 

The O2 inhibitory effect, which is illustrated in Figure 6 for a typical UV-curable acrylate resin, is particularly important in thin films and at the surface of samples in contact with air. It becomes more pronounced when the light intensity is decreased because of the increasing duration of the polymerization, time during which atmospheric oxygen diffuses into the sample. 

Rietschel RL, Huggins R, Levy N, Pruitt PM (1984) In vivo and in vitro testing of gloves for protection against UV-curable acrylate resin systems. Contact Dermatitis 11 279-282 Zimmerman EH (1981) Letterflex in printers. Derm News ... 

Low shrinkage and good adhesion was also achieved by using waterbased UV-curable acrylate resins, like Laromer PE-55W from BASF, associated to Irgacure 2959 from Ciba SC as photoinitiator. After drying at 80°C, the tacky film obtained proved to be an excellent adhesive to assemble glass plates or transparent films by a short exposure to UV-radiation, which transforms the tacky resin into a low-modulus elastomer. The multiple-step processing can be represented schematically as follows ... 

Decker, C. and Moussa, K., UV-curable acrylic resins for production of glass laminates, J. Appl. Polym. Sci, 1995, 55, 359-369. 

A standard UV-curable acrylate resin formulation consists of at least three ingredients a photoinitiator, an acrylate resin, and a reactive diluent. 

UV-Curable Acrylic resins for PSAs, by Dr Karl-Heinz Schumacher, development chemist, BASF AC, Ludwigshafen, Germany and Tim Sanborn, technical adviser, BASF Corp., Charlotte, NC... 

Acrylated tackifying oligomers and UV-curable acrylic resins for PSA applications. 

A typical formulation of a photocurable composite resin contains four basic components a radical-type photo initiator, an acrylate functionalized oligomer, a reactive diluent and the clay mineral filler. The photoinitiator is usually an aromatic ketone which cleaves into two radical fragments upon UV exposure. The telechelic oligomer consists of a short polymer chain (polyurethane, polyether, polyester) end-capped by the very reactive acrylate double bond. An acrylate monomer is generally used as reactive diluent to reduce the resin viscosity. Figure 7.2 shows some typical compounds used in UV-curable acrylic resins. Different types of phyllosilicates were selected as mineral filler an organophilic clay (Nanomer I-30E from Nanocor), native hydrophilic clays (montmorillonite KIO and bentonite) and a synthetic clay (beidellite). 

Typical compounds used in UV-curable acrylic resins. 

Fig. 21 Representative microfluidic device and resulting data from ATRP on a chip a image of a microfluidic device (dimensions 25 mm x 75 mm) fabricated from UV curable thiolene resin between two glass slides b reaction data for ATRP of HPMA synthesized on a chip showing the correlation of flow rate (or residence time) to reaction time and resulting conversion of monomer (M) to polymer (ln([M]o/[M]) c comparison of number average molecular mass (M ) and poly-dispersity for -butyl acrylate prepared in a traditional round bottom flask ( Flask ) and on a chip ( CRP Chip ). (Reproduced with permission from [102])...

The polymer layer, fypically between 250 and 1,000 nm thick, is deposited by flash evaporahon of a multicomponent proprietary UV curable acrylate-based resin system. The requirements for the deposited film are ... 

Even more important to the formulation is a photoinitiator for the UV curables or an accelerator for the EB curables. These do not necessarily have to be a separate ingredient, but they may be a molecular modification of a resin or monomer ingredient. A typical photoinitiator for a UV curable acrylic system is based on an aromatic keto compound, and for an epoxy system it is based on a diazonium or a sulfonium compound. 

A recent application of photopolymerization is the protection of the surface of optical components made of polycarbonate or acrylic resins. The surfaces of these parts are vulnerable to scratches and attack by chemicals. Coating of the surface with a thin layer (2-4 pm) of a UV-curable acrylic coating may increase the abrasion resistance and the chemical inertness considerably. 

In earlier times physical prototypes may have been hand carved out of wood or molded from clay. In modern times, polymers are the materials used most widely in RP applications. These materials include ABS, nylon, and UV-curable photopolymer resins such as epoxy, acrylates, and vinyl-ethers. This chapter describes the various techniques and devices nsed to produce RP parts and details of the polymer materials that are used. Advantages and disadvantages of different techniques such as accuracy and strength of the product are considered. 

On-aircraft repairs of composite using a rapid-cure resin system of composite component with UV light irradiation based on TRI patenP have been developed by the U.S. Air Force Research Laboratory. Alternating layers of the acrylate-based resin system and woven fiberglass (the widely used wet la)mp procedure) are applied to fill the hole and form a UV curable composition. The width of the patch can be up to 2 ft (0.6 m) and the depth as much as 0.2 in. (5 mm). The cure time using a 400 W UVA lamp is reported to be 20 min. Although it is essentially a depot repair, it can be done field when necessary to return an aircraft to service. Because of the necessity to cure relatively thick repair patches, Us-acylphosphine oxide was used as a photoinitiator. An example of the patented UV curable resin system used for the repairs is in Table 11.1. 

The majority of the monomers and oligomers used in UV curable inkjet ink formulations are acrylates of varying functionalities, although occasionally materials such as unsaturated polyester resins are used as well. Figure 2 shows examples of the acrylate moiety. Acrylates are skin sensitizers and should be handled with caution. 

Photopolymer systems are photocurable resins incorporating reactive liquid monomers, photoinitiators, chemical modihers and hhers. Typically stereolithography utilizes UV radiation, so UV-curable systems are used. Free-radical-photopolymerizable acrylate systems were originally used however, newer cationic epoxy-resin and vinyl ether systems (based on iodinium- or sulfonium-salt cationic initiators) are now being utilized. 

As mentioned earlier, UV-curable resin formulations are very attractive for fiber coating because of the rapid cross-linking rates that are achievable. Most commonly, epoxy- or urethane-acrylate resins are employed (18-22), and viscosity and cross-link density are controlled through the addition of reactive diluents. With these systems work has focused on producing low modulus, low T properties (20-22) through the incorporation of appropriate chemical constituents to enhance higher chain flexibility, for example, ether linkages. 

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