Health aspects of the curing of synthetic rubbers.

Abstract

A commonly used tread rubber formulation was cured in the laboratory under conditions simulating vulcanization in the Bag-O-Matic press. Volatile emissions were collected on charcoal and analyzed by combined GC-mass spectrometry. The compounds identified were either contaminants present in the raw material or reaction products. Some of these compounds were also identified in charcoal tube samples collected in the atmosphere of the industrial operations. Estimates based on the loss of weight of rubber during curing were used to predict airborne concentrations and compared to the concentrations actually found. The literature of the toxicity of raw materials and effluents was reviewed, and no acute or chronic toxicological effects would be anticipated. Information concerning potential carcinogenicity was not available and could not be evaluated.

Sources of fine organic aerosol. 3. Road dust, tire debris, and organometallic brake lining dust: roads as sources and sinks

“…In addition, vulcanization and acceleration agents are necessary during the production process. Typically up to 1 % of the processing stock mass consists of vulcanization accelerators such as thiazoles, sulfenamides, and others (11,14,15). In order to accelerate the curing process further, organic activators such as zinc salts of a mixture of fatty acids, primary fatty amines, organic and inorganic acetates, and other accelerators are added to the stock solution (22).…”

“…Extenders such as aromatic and naphthenic oils are used to substitute for part of the more costly rubber material and constitute 10-20% of the stock formula. Truck tires, exposed to tougher physical conditions, usually contain small amounts of such organic extender oils (12,14,15). Plasticizers, which are primarily used to reduce the viscosity during milling of the uncured stock rubber, are added in low amounts (22).…”

“…have to be added to the rubber material. Waxes, consisting of higher n-alkanes (sunproof waxes) are used in quantities ranging from 0.5 to 1.0% of the rubber material and serve both as softeners and as UVand ozoneprotecting agents (11,14,15). Together with the aromatic and naphthenic-type compounds added as extenders, additional n-alkanes are introduced into the rubber stock (16).…”

“…Confirmation and quantification of organic compounds was obtained through the use of more than 150 authentic standards, as described by Rogge et al (8). The following standard mixtures were injected onto the GC/MS systems: (1) normal alkanes ranging from n-Cio to n-Cse', (2) normal alkanoic acids as methyl esters ranging from n-C% to n-Cao; (3) unsaturated aliphatic acids such as oleic acid and linoleic acid as methyl esters; (4) normal alkanols ranging from n-Cio to n-Cso; (5) several phenolic compounds, benzaldehydes, and substituted aromatic acids; (6) a suite of 39 aromatic and polycyclic aromatic hydrocarbons (PAH); (7) 10 polycyclic aromatic ketones and quiñones; (8) a set of eight aromatic and polycyclic aromatic Nand S-substituted compounds; (9) steroids including cholesterol and cholestane; (10) a set of four phytosterols; (11) several natural resins; (12) plasticizers; (13) a suite of 11 aliphatic dicarboxylic acids (C3-C10) as methyl esters; (14) a suite of seven aromatic diand tricarboxylic acids, all as their methyl esters; and (15) other compounds.…”

Short-Term Bioassays in the Analysis of Complex Environmental Mixtures III

“…The mutagenicity tests were conducted on condensed curing fumes generated in a laboratory. The chemical complexity of the condensates reported by others (Fraser and Rappaport, 1976;Willoughby and Lawson, 1979) was confirmed by gas chromatography (GC). Chemical separation of one chloroprene rubber condensate was performed in order of increasing polarity, and the fractions were tested for mutagenicity.…”