Photopolymer resins

The Photopolymer Plate produces images by simple dissolution of unexposed areas of the photopolymer resin. However, in case of... 

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. 

A number of photopolymer printing plates are already known. Their basic structures are to combine one of the general purpose resins such as cellulose (1), polyamide (2J, polyester, poly urethane (3j, polyvinyl alcohol (4), synthetic rubber (5) and the like with photopolymerizing vinyl monomer, photopolymerization initiator and so on. Any one of the plates of such structures can be used as a press plate, but they can not be used as an original plate for duplicate plate owing to their insufficient hardness, toughness and the similar negative properties. 

The Photopolymer Plate of over 85° Shore D hardness can stand temperatures over 160°C, and it could be successfully used as a master plate for making thermoformed matrix of phenol group resin to be used for thermoformed polymer printing plates such as rubber plates and the like under conditions of 30 kg/cm2 pressure... 

Two of the main considerations in the development of totally reactive liquid photopolymer systems are the resin(s) and the reactive diluents (monomers). The resins play a major role in determining the end properties and therefore the applications of the cured polymer. The reactive diluents are used to provide a fully reactive system with the appropriate reactivity, viscosity, coatability before cure and the desired crosslink density, chemical resistance and dielectric character once it is cured. The pho-toreactive monomers most commonly used are acrylate based derivatives because of the properties they impart, and their high reactivity and wide solubility range. 

Vesicular films have a honeycomb-like cross-section and are constructed of a polyester base coated with a thermoplastic resin and a light-sensitive diazonium salt. Photopolymer films contain carbon black as a substitute for silver. These films are processed in a weak alkaline solution that is neutralized prior to disposal. As such, they produce a nonhazardous waste. 

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. 

TM for a line of organic and inorganic industrial chemicals, synthetic resins, synthetic rubber, high-compound fertilizers, coating materials, latexes, pharmaceutical and food additives, explosives, photopolymers and platemaking systems, separation... 

To investigate the kinetics that control the rate of network connection of a highly cross-linked photopolymer system, Lovell et al. (2001) utilized rapid scan near-infrared (NIR) spectroscopy to study the polymerization of a dimethylacrylate dental resin. The research exploited the Thermo Electron rapid-scan capabilities to analyze the system with a time resolution of ss 30 ms. This was sufficiently faster than traditional techniques, which required data collection at the 2-second time scale and would thus miss the reaction of interest that reacts to... 

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. 

Reiser, Photoactive Polymers The Science and Technology of Resists, pp. 38 39, John Wiley Sons, Hoboken, NJ (1989) N.J. Turro, Modern Molecular Photochemistry, Benjamin Cummings, Menlo Park, CA (1978) S. Nonogaki, M. Hashimoto, T. Iwayanagi, and H. Shiraishi, Azide pheno lie resin resists sensitive to visible light, Proc. SPIE 539, 189 (1985) M. Hashimoto, T. Iwayanagi, H. Shiraishi, and S. Nonogaki, Photochemistry of azide phenolic resin photoresists, presented at Tech. Pap., Photopolym. Conf. SPE, Ellenville, NY, Oct. 1985. 

H. Ito and E. Flores, Evaluation of onium salt cationic photoinitiators as novel dissolution inhibitor for novolac resin, J. Electrochem. Soc. 135,2322 (1988) H. Ito, Aqueous base developable deep UV resist systems based on novel monomeric and polymeric dissolution inhibitors, Proc. SPIE 920, 33 (1988). T. Aral, T. Sakamizu, K. Katoh, M. Hashimoto, and H. Shiraishi, A sensitive positive resist for 0.1 p,m electron beam direct writing hthography, J. Photopolym. Sci. Technol. 10, 625 (1997). 

Przybilla, R. Dammel, H. Rdschert, W. Spiess, and G. Pawlowski, New t hoc blocked poly mers for advanced lithographic applications, J. Photopolym. Sci. Technol. 4, 421 (1991) K. Przybilla, H. Roschert, W. Spiess, C. Eckes, S. Chatterjee, D. Khanna, G. Pawlowski, and R. Dammel, Progress in DUV resins, Proc. SPIE 1466, 174 (1991). 

Polyester-styrene resins have a low raw material price and are used in wood finishing. Disadvantages are the presence of volatile styrene and the low cure speed. Products with methacrylic groups are used where line (cure) speed is less important, mainly in combination with acrylates in special end uses (e.g., in the electronics industry and in photopolymer printing plates) to improve adhesion or to obtain specific physical properties. Thiol- thiene mixtures can lead to very flexible cured films but their odor seriously limits their use. 

The fundamental process of SLA is the solidification process of a liquid photopolymer, for example an epoxy resin. It is interspersed with suitable photoinitiators and exposed to ultraviolet (laser-) radiation, which initiates polymerization in those areas where the resin is heated by the laser beam according to the cross-sections. The beam deflection is realized by a scanner system consisting of two movable mirrors [102]. The curing is limited in the horizontal direction by the diameter of the laser beam and in the vertical direction by the optical penetration depth of the used resin. After completion of a layer the platform moves down according to the layer thickness and new resin is coated. After finishing the build process the model requires post-processing, in which the model is cleaned, the support removed and post-cured in a UV-hght chamber. 

Uses Adduct monomer for preparation of thermosetting acrylic resins with improved flexibility for paint systems also used in photopolymer production and adhesive applies. 

Chem. Descrip. Aliphatic urethane acrylate resin/SR 454 (ethoxylated trimethylolpropane triacrylate) blend, < 400 ppm MEHQ inhibitor Uses Urethane-acrylic for adhesives, coatings (metal, paper, PVC floor, wood), electronics, inks, photopolymers Features High performance difunctional oligomer hard, nonyellowing Properties APHA 100 clear liq. sp.gr. 1.104 vise. 2300 cps tens. str. 9000 psi tens, elong. 31% 99% reactive esters 75% oligomer, 25% EOTMPTA... 

CAS 2867-47-2 EINECS/ELINCS 220-688-8 Uses Adhesion promoter mfg. of quats improves thermoplastics of textile fibers photopolymer plates photoresists paint resins oil additives electro dipcoats rubber modifiers dental compds. flocculants water-... 

CAS 5205-93-6 EINECS/ELINCS 226-002-3 Uses Adhesion promoter, mfg. of quats, improves dyeability of textile fibers, photopolymer plates, photoresists, paint resins and emulsions, oil additives, electro dipcoats, rubber modifiers, dental compds. Properties Pt-Co 50 max. clear liq. ester-like odor m.w. 170 sp.gr. 0.94 vise. 28 cps (20 C) b.p. 134 C flash pt. 140 C ref. index 1.478 (20 C) 98.5% min. purity 0.1% water content Toxicology TSCA listed Storage 3 mos shelf life 30 C max. 

CAS 868-77-9 EINECS/ELINCS 212-782-2 Uses Crosslinkable paint resin binder for textiles/paper adhesives urethane methacrylates reactive thinners grafting of textile fibers scale inhibitors adhesion promoter for polymers hydrophilic polymers lt.-cuting polymer systems rubber modifiers contact lenses photopolymer plates photoresists... 

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