Polyester curatives: product lines reviewed.

POLYESTER CURATIVES PRODUCT LINES REVIEWED

ABCO INDUSTRIES, LTD.

Abcure S-40-25 is a sprayable 40% emulsion of BPO in water. It is recommended as an alternative to MEKP in applications that can tolerate the introduction of water with the catalyst. This product can be stored at room temperature and in large quantities, and does not require a yellow label for transportation.

AIR PRODUCTS AND CHEMICALS, INC.

Manufactures polyester promoters for the rapid cure of glass-reinforced molding compounds.

AKZO CHEMICALS INC.

Manufactures a series of cobalt organometallic complexes, referred to as NL-accelerators, for promoting unsaturated polyester resins. In addition, other metal complexes are offered for specialty uses in polyester systems requiring ambient and elevated-temperature cures.

An extensive range of organic peroxides is offered for curing polyester resins over a wide range of temperatures and processing conditions. Products include various ketone peroxides and a broad range of granular, paste, and emulsion grades of BPO. Initiators for SMC and BMC formulations include peroxyesters and peroxyketals. Company also offers organic peroxides for high-temperature molding, and a medium-range difunctional peroxide.

Several photo-initiators are available for uv curing of polyesters. Other products include di-t-butyl peroxide, t-butyl hydroperoxide and peroxydicarbonates, and specialty organic peroxides.

ATOCHEM NORTH AMERICA, INC.

A wide range of peroxide initiators is supplied for curing polyesters processed by contact molding (hand lay-up, spray-up, filament winding), cold molding, pultrusion, and other methods. Products include ketone peroxides, peroxyketals, peroxyesters, dialkyl, diacyl and hydroperoxides.

AZTEC CATALYST CO.

SUB. OF CATALYST RESOURCES, INC.

Produces a line of peroxide initiators which includes diacyl peroxides, hydroperoxides, peroxyesters, peroxyketals and custom blends.

Peroxyesters include three strengths of t-butyl peracetate, t-butyl peroxybenzoate, t-amyl peroxybenzoate, t-butyl peroxypivalate, and three solutions of t-butyl peroctoate.

Also produces grades of benzoyl peroxide: dry, 97% minimum; 70% in water; and 77% in water. Also offered is a peroxyketal/peroxyester blend known as Aztec TKB.

Products come in a variety of packages from 1-gallon bottles to dedicated bulk tank trucks.

BUFFALO COLOR CORP.

Supplies dimethyl aniline and diethyl aniline for use as promoters in molding-grade polyester resins.

CATALYST SYSTEMS INC.

U.S. CHEMICAL & PLASTICS

Supplies benzoyl peroxide in paste and granular forms. Pastes are normally 50% (pigmented or unpigmented), though other formulations are available. Pourable/pumpable pastes at 40% or less are also available. Granules are offered in 70%, 75%, and 78% versions. Pastes are offered in 380-lb drums or tubed in 3/4-, 1-, 2 3/4- or 4-oz tubes. Private label tubes also can be filled.

Company also offers Mono-Pak custom additive packages for elevated-temperature molding of reinforced plastics. These packages may contain catalysts, mold releases, thickeners, and pigments as specified. Preweighed mixtures of additives are supplied in a soluble package that can be dropped unopened into the resin mix. The method is said to eliminate preweighing, save labor, simplify inventories, and eliminate rejects caused by weighing errors involving critical additives.

COOK COMPOSITES & POLYMERS CO.

Peroxide initiators include MEKP and other ketone peroxides, t-butyl perbenzoate, t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, and BPO paste. Company's new MEKPS include the following:

* Thermacure ZAP 25 is a specific application catalyst made from a blend of ketone peroxides, which is said to give a shorter gel time with a quicker cure and barcol development. Designed primarily for tub/shower and marine applications. Product is not to be used on gel coats.

* Thermacure ZAP 50 is a blend of ketone peroxide that produces the same characteristics as ZAP 25 but in about 5% less time. Designed primarily for marble onyx applications. Product is not to be used on gel coats.

COOK PAINT & VARNISH CO. Supplies MEK peroxides.

DU PONT CO.

Vazo 52, 64, 67, and 88 nitrile-based compounds are primarily used as polymerization initiators of vinyl monomers but are also useful in polymerization of unsaturated polyesters.

EASTMAN CHEMICAL PRODUCTS

Offers ethyl acetoacetate, methyl acetoacetate, dimethyl acetoacetamide, monomethyl acetoacetamide, and acetoacetanilide for use as low-color copromoters for room-temperature cure of unsaturated polyesters.

HERCULES INC.

Di-Cup dicumyl peroxide and Vul-Cup [a,a'-bis (tertiary butylperoxy) diisopropylbenzene] are used in processing unsaturated polyester at temperatures over 250 F and can also be used with other peroxide to improve performance.

HULS AMERICA, INC.

Organometallic promoters for polyesters include three products:

* A cobalt/potassium complex, trademarked Copac, which can be used to extend more costly cobalt promoters and reduce color.

* Nuxtra Cobalt-12%, a standard cobalt promoter.

* Nuodex Cobalt 254, a cobalt modifier-promoter, which helps control the speed of gel promotion and prevent gel-time drift.

MONTEDISON USA, INC.

Curing agents for polyester resins include several peroxides under the Peroximon brand: MEK peroxide (K1 and K10), methylisobutyl ketone peroxide (K2), acetylacetone (K3), and cumene hydroperoxide (CH).

MOONEY CHEMICALS, INC.

Promoters for polyesters include cobalt octoate, cobalt naphthenate, and other cobalt compounds. Potassium octoate, Poly-Cure 503, a promoter containing cobalt, plus synergistic proprietary ingredients, and manganese-based compounds are also supplied.

NORAC CO., INC.

Offers a line of room-temperature cure initiators, including organic peroxides such as MEKP, AAP, and BPO. Higher-temperature peroxyesters, such as TBPB and TBPO are also offered for use in SMC/BMC. Company's Sty-Pac Division offers preweighed, custom peroxyester/stearate mixtures. Blends of initiator/mold releases that are pumpable are offered for automatic metering.

PPG INDUSTRIES, INC.

Makes a range of percarbonate organic peroxides, some of which are said to be useful for curing or cross-linking applications in polyesters.

POLYPRODUCTS CORP.

Supplies a special grade of MEK peroxide designed for safety, which does not require a yellow label.

REICHHOLD CHEMICALS, INC.

REACTIVE POLYMERS DIV.

Offers 13 products in their line of MEK peroxides for catalyzing polyesters. Products are said to be suited to all types or processing. Benzoyl peroxide is available as wet granules, paste dispersions, and a 40% liquid dispersion.

SCHERING BERLIN POLYMERS INC.

Offers two azo-polymerization initiators: Ficel AZDN (azobisisobutyronitrile), and Ficel AZM (azobis-2 methylbutylronitrile). Products are used in free-radical polymerizations, including polymerization of unsaturated polyesters.

WITCO CORP., ARGUS DIV.,

U.S. PEROXYGEN PRODUCTS

Supplies a full line of organic peroxide initiators for curing polyesters. Ketone peroxides for polyesters include Hi-Point 90, Quickset Super, Quickset Extra, Esperfoam FR, and USP-240. Several forms of benzoyl peroxide paste and granules are available. Peroxides for high-temperature curing of SMC, BMC, and TMC are peroxyesters and peroxyketals such as Esperox 57OP, USP-245, Esperox 28PD, Esperox 10, Esperox 497P, and USP-400P. USP-90PD, also a peroxyketal, is said to be particularly useful for its enhanced efficiency.