Epoxy resins, additives Flame retardants

Schartel B, Balabanovich AI, Braun U, Knoll U, Artner J, Ciesielski M, Doring M, Perez P, Sandler JKW, Altstadt V, Hoffmann T, Pospiech D. Pyrolysis of epoxy resins and fire behaviour of epoxy resin composites flame-retarded with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide additives. J. Appl. Polym. Sci. 2007 104 2260-2269. 

TetrabromobisphenolA. TBBPA is the largest volume reactive flame retardant. Its primary use is in epoxy resins (see Epoxyresins) where it is reacted with the bis-glycidyl ether of bisphenol A to produce an epoxy resin having 20—25% bromine. This brominated resin is typically sold as a 80% solution in a solvent. TBBPA is also used in the production of epoxy oligomers which are used as additive flame retardants. 

Most circuit boards are FR-4 boards that meet standards for fire safety by the use of brominated epoxy resins in which the reactive flame-retardant tetrabromobisphenol A (TBBPA) forms part of the polymeric backbone of the resin. Alternative flame-retardant materials are used in only 3-5 per cent of the FR-4 boards, but additional alternative flame-retardant materials are also imder development. Little information exists concerning the potential environmental and human health impacts of the materials which are being developed as alternatives to those used today that are based on brominated epoxy resins. 

Bromide analysis, of water, 26 41 Bromide ions, in development solution, 79 205-206 Bromides, 4 319-330 thorium, 24 763 titanium, 25 54 tungsten, 25 379 uranium, 25 439 Bromimide, 4 299, 319 Brominated additive flame retardants, 77 461-468, 471-473t Brominated Anthanthrone Orange, pigment for plastics, 7 367t Brominated aromatic compounds, 7 7 459 Brominated bisphenol A-based epoxy resins, 70 366... 

This paper reports the results of a molecular-level investigation of the effects of flame retardant additives on the thermal dedompositlon of thermoset molding compounds used for encapsulation of IC devices, and their implications to the reliability of devices in molded plastic packages. In particular, semiconductor grade novolac epoxy and silicone-epoxy based resins and an electrical grade novolac epoxy formulation are compared. This work is an extension of a previous study of an epoxy encapsulant to flame retarded and non-flame retarded sample pairs of novolac epoxy and silicone-epoxy compounds. The results of this work are correlated with separate studies on device aglng2>3, where appropriate. 

Additive flame-retardant compounds include brominated epoxy resins, chlorinated hydrocarbons, decabromodiphenyl ether, and pentabromodiphenyl ether. Where transparency is not important, antimony oxide can be used as a synergist to reduce the amount of halogen required. 

Chem. Descrip. Tetrabromophthalic anhydride CAS 632-79-1 EINECS/ELINCS 211-185-4 Uses Flame retardant in prod, of unsat. polyester resins and rigid PU polyols cohardener for epoxy resins additive for latex emulsions derivs. used as flame retardants in diverse applic. (adhesives, wire coating, and wool, etc.)... 

Among phosphorus-containing additive flame-retardants, phosphates are mostly applied as secondary plasticizers in formulations of flame-retarded plasticized PVC. Other additive agents are admixed with natural and synthetic rubbers, polyester and epoxy resins, polyurethane foams, polystyrenes and polyethylenes, etc. 

Halogenated additive flame-retardants may also be admixed with the resin. Tetra-bromo-p-xylene, pentabromobenzyl bromide, pentabromoethyl benzene, pentabro-motoluene, tribromocumene, decabromodiphenyl oxide, and brominated epoxy resins are some of the compounds used. 

They are used mostly as reactive flame retardants for epoxy resins (especially those applied for manufacturing of the printed circuit boards) and as an additive flame retardants for acrylonitrile butadiene styrene polymers used for production of electronic equipment (e.g., monitors and cellular phones). 

Polymers, including the various types of epoxy resins, differ in their inherent flammability The types of resins and curing agents selected can impact the fundamental flammability of the resin system and determine how much additional flame-retardant components are needed to achieve the desired flammability rating. For example, polymers with a high concentration of... 

TBBPA has found use as a reactive flame retardant in the production of epoxy and polycarbonate resins added to circuit boards used in computers and in many other devices. In about 10% of cases TBBPA is used as an additive flame retardant, especially in the production of acrylonitrile-butadiene-styrene polymers, polystyrene, papers, textiles, televisions, office equipment and others. 

Nickel dialkyldithiocarbamates stabili2e vulcani2ates of epichlorhydrinethylene oxide against heat aging (178). Nickel dibutyldithiocarbamate [56377-13-0] is used as an oxidation inhibitor in synthetic elastomers. Nickel chelates of substituted acetylacetonates are flame retardants for epoxy resins (179). Nickel dicycloalkyldithiophosphinates have been proposed as flame-retardant additives for polystyrene (180—182) (see Flame retardants Heat stabilizers). 

The binder system of a plastic encapsulant consists of an epoxy resin, a hardener or curing agent, and an accelerating catalyst system. The conversion of epoxies from the Hquid (thermoplastic) state to tough, hard, thermoset soHds is accompHshed by the addition of chemically active compounds known as curing agents. Flame retardants (qv), usually in the form of halogens, are added to the epoxy resin backbone because epoxy resins are inherently flammable. 

Paints are complex formulations of polymeric binders with additives including anti-corrosion pigments, colors, plasticizers, ultraviolet absorbers, flame-retardant chemicals, etc. Almost all binders are organic materials such as resins based on epoxy, polyurethanes, alkyds, esters, chlorinated rubber and acrylics. The common inorganic binder is the silicate used in inorganic zinc silicate primer for steel. Specific formulations are available for application to aluminum and for galvanized steel substrates. 

Phosphorus flame retardants, 77 484-510 additive organic, 77 488-489 commercial, 77 487-499 economic aspects of, 11 503 in epoxy resins, 77 499-501 health, safety, and environmental factors related to, 77 501-503 interaction with other flame retardants, 77 486... 

Among the emerging pollutants of industrial origin, Bisphenol A [2,2 bis(4-hydroxydiphenyl)pro-pane] (BPA) has special relevance since it was one of the first chemicals discovered to mimic estrogens as endocrine disrupters.147 This compound was first reported by Dianin in 1891.1411 BPA is produced in large quantities worldwide, mainly for the preparation of polycarbonates, epoxy resins, and unsaturated polyester-styrene resins.149 The final products are used in many ways, such as coatings on cans, powder paints, additives in thermal paper, in dental composite fillings, and even as antioxidants in plasticizers or polymerization inhibitors in polyvinyl chloride (PVC). To a minor extent, BPA is also used as precursor for flame retardants such as tetrabromobisphenol A or tetrabromobisphenol-S-bis(2,3-dibromopropyl) ether.150 This substance can enter the environment... 

Brominated Epoxy Resins. The conventional DGEBA epoxy resins are flammable when cured. In an adhesive, flammability is generally not considered critically important because the mass of adhesive in any one area is relatively small. However, in certain applications (printed-circuit manufacture, aircraft interiors, furniture, etc.) nonflammability is an important criterion. Flame-retardant additives and chlorinated curing agents have been used to impart nonflammability to epoxy resins. 

Standard epoxy resins are usually blended with brominated epoxy resins to provide the concentration of bromine required to provide ignition temperature resistance. Brominated resins have also been used as flame-retardant additives in thermoplastic compounds. 

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