Stabilizers unsaturated polyesters

TetrabromophthalicAnhydride. Tetrabromophthalic anhydride [632-79-1] (TBPA) is widely used as a reactive flame retardant in unsaturated polyesters as weU as the precursor to a number of other fine retardants. Polyesters prepared from this compound have relatively poor photochemical stabiUty and tend to discolor upon exposure to light. This tendency to discolor can be reduced, but not eliminated, by the use of uv stabilizers. 

Catalyst selection, in unsaturated polyester cross-linking, 20 107-109 Catalyst Stabilization Technology (CST), 23 337... 

In polystyrene, polymethacrylate, unsaturated polyester resins, or similar media, P.R.31 affords highly transparent colorations of medium red shades, which are used as automobile tail lights and for other signalling purposes. Its heat stability in... 

P.B.15 3, like stabilized a-Copper Phthalocyanine Blue, markedly affects the hardening of unsaturated polyester cast resins. The list of applications also includes PUR foam materials, office articles, such as colored pencils, wax crayons, and water colors, as well as spin dyeing of polypropylene, polyacrylonitrile, secondary acetate, polyamide, polyester, and viscose. Used in polyester spin dyeing, P.B.15 3 satisfies the thermal requirements of the condensation process (Sec. 1.8.3.8). 1/3 and 1/25 SD samples equal step 7-8 on the Blue Scale for lightfastness. Textile fastnesses, such as stability to wet and dry crocking are perfect. 

P.R.149 also lends color to cast resins made from materials such as unsaturated polyester or methacrylic acid methylester, which are polymerized with peroxide catalysts. P.R.149 is equally lightfast in these media. In polycarbonate, the pigment tolerates exposure to more than 320°C. This is an asset in view of the fact that polycarbonate shows high melt viscosity and is thus processed at up to 340°C. The list of applications also includes other media, such as PUR foams and elastomers, for which P.R.149 is recommended because of its good heat stability and its coloristic properties. 

The weatherability and hydrolytic stability of unsaturated polyesters based on neopentyl glycol have made it a popular intermediate for use in formulations exposed to severe conditions, eg, in gel coats for cultured marble and marine applications (see Coatings, MARINE) (13). 

Alkyds are formulated from polyester resins, cross-linking monomers, and fillers of mineral or glass. The unsaturated polyester resins used for thermosetting alkyds are the reaction products of polyfunctional organic alcohols (glycols) and dibasic organic acids. Key properties of alkyds are dimensional stability, colorability, and arc track resistance. Chemical resistance, however, is generally poor. 

Another important application is the introduction of a thermoplastic such as poly(vinyl acetate), PVAc, into an unsaturated polyester resin to improve dimensional stability of the mold part. Keeping in mind (sec. 2.3.2) that an unsaturated polyester is dissolved in styrene, the modifier is the third component and the behavior is described with the help of a ternary-phase diagram (Fig. 8.3, Suspene et al., 1991). 

Incorporation of modified clays into thermosetting resins, and particularly in epoxy35 or unsaturated polyester resins, in order to improve thermal stability or flame retardancy, has been reported.36 A thermogravimetric study of polyester-clay nanocomposites has shown that addition of nanoclays lowers the decomposition temperature and thermal stability of a standard resin up to 600°C. But, above this temperature, the trend is reversed in a region where a charring residue is formed. Char formation seems not as important as compared with other polymer-clay nanocomposite structures. Nazare et al.37 have studied the combination of APP and ammonium-modified MMT (Cloisite 10A, 15A, 25A, and 30B). The diluent used for polyester resin was methyl methacrylate (MMA). The... 

Manfredi, L. B., Rodriguez, E. S., Wladyka-Przybylak, M., and Vazquez, A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres, Polym. Degrad. Stabil. 2006, 91, 255-261. 

Dialkylperoxides are used as high temperature catalysts for suspension and bulk polymerization as well as hardeners for unsaturated polyester resins and for cross-linking polymers because of their good thermal stability. While the liquid di-tert-butylperoxide is relatively volatile at application temperatures, dicumylperoxide is much less volatile and has the disadvantage of forming decomposition products with intense odors (acetophenone)(Chapter 13). 

As a preliminary step in the manufacture of unsaturated polyester thermoset plastic one uses low molecular weight linear polyester (Mr 10,000) obtained by a polycondensation of polyglycols with saturated and unsaturated dicarboxylic acids. The precondensate can then be dissolved and stored in the stabilized comonomer, e.g. styrene, with which it will be crosslinked later. The crosslinking polymerization reaction between the polyester chains and the styrene bridges is initiated with the help of organic peroxides which are added dispersed in plasticizers. The reaction begins at 60-90 °C and then proceeds exothermally. In addition to this a cold hardening reaction can also be carried out. For this reaction cold accelerators are necessary, e.g. tertiary amines or cobalt naphthenate. 

Velsicol Chemical LLC, formerly Velsicol Chemical Corporation, designs, manufactures, markets and distributes high performance specialty chemicals and industrial intermediates, primarily based on benzoic acid and the organic compound cyclopentadiene. Its products include chlorendic anhydride and hexachlorocyclopentadiene (HEX). Chlorendic anhydride is corrosion resistant, fire resistant and has high UV stability, and is used in the synthesis of flame retardant polymers such as polyurethanes, unsaturated polyester and epoxy resins. HEX, a reactive intermediate used in the manufacture of agricultural pesticides in the production of flame retardants for the wire and cable industry and in the preparation of chlorendic anhydride. The company s products are produced primarily at a plant in Memphis, Tennessee Velsicol also maintains the Memphis Environmental Center (MEC), which focuses on managing legacy environmental liabilities. The firm is owned by Arsenal Capital Partners, a private equity firm. 

UV stabilizer particularly effective in styrenic polymers, PVC, unsaturated polyesters, polyurethanes, acrylic polymers and polycarbonates. 

Plasticizer solution containing 20% methyl ethyl ketone peroxide, stabilized with dimethyl phthalate and and a proprietary safety diluent, used principally in the curing of promoted unsaturated polyester resins where an extended catalyst is desired for improved concentration control. 

The polymer eomponent, whieh is a thermosetting resin, forms eross-linked bonds between chains of molecules, whieh enhanees the eharacteristic of the produet. Unsaturated polyesters and vinyl esters are primarily used as resin systems. Epoxies are also used in some eases, but the eure eyele is longer. Phenolic resins have gained importanee these days because of their inherent properties, especially in applications that require lower flammability, reduced smoke generation, and higher thermal stability. New resin systems such as... 

Because unsaturated polyesters are widely used as material for the mechanical, electrical and building industries, for skis, huts, disposable tanks and various containers used outdoors, it is important to stabilize them against sun light irradiation. In this paper we present results of the photostabilization of cured polyesters using commercially produced photostabilizers. 

There are two basic VPI resin formulations. One is based on epoxy resins, and the other is based on unsaturated polyesters. Both are typically one-part solventless compositions that are completely polymerizable. Volatile, nonpolymerizable solvents cannot be tolerated because these will lead to bubbling in the vacuum impregnation procedure. To control viscosity of the resin formulations, the epoxies contain low-viscosity, reactive diluents of the monoglycidyl ether type the unsaturated polyester formulations contain styrene or vinyltoluene as reactive diluents. Both resin types contain catalysts that become active only at elevated temperatures to insure long-term stability at room temperature. The epoxy resins are frequently catalyzed with metal organic compounds such as titanium complexes, and peroxides are usually the main catalyst in the unsaturated polyester formulations. In addition to the ingredients mentioned here, the compositions may contain additives such as cocatalysts, activators, and accelerators. However, there are no particular fillers used in VPI resins. 

Talc - Talc is a filler made by dry or wet grinding of mineral magnesium silicate. Talc improves stiffness, dimensional stability, flexural modulus, creep resistance, flow, surface smoothness, moisture resistance, tensile strength, and wear resistance of plastics. It also increases heat deflection temperature and decreases vapor permeability. Can be used as a film antiblock agent. Used mainly in polypropylene but also in thermoplastic and unsaturated polyesters and epoxy resins at low levels. Surface-modified grades are available. 

Hydroxy-3 -t-butyl-5 -methylphenyl)-5-chioro-benzotriazole. Bumetrizol Bumetrizole Bumetrlzolum 2-t-Butyl-6-(5-chloro-2H-benzotriazol-2-yl)-p-cresoi 2-(5-Chloro-2H-ben20triazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol EINECS 223-445-4 2-(2-Hydroxy-3-t-butyl-5-methyl-phenyi)-5-chloro-2H-benzotriazole 2-(2-Hydroxy-3 -t-butyl-5 -methylphenyl)-5-chloroben20-triazole Lowltit 26 Phenol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-( 1,1 -dimethylethyl)-4-methyl- Tinuvin UV Absorber-6 Uvazol 236. UV stabilizer for polyolefins, polyester resins and coatings, Used to protect polyolefins, slyrenics, acrylics, PVC, unsaturated polyesters, elastomers, PC, and PU, EniChem SpA Lowi. 

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