Glycols from paints

Even low air concentrations of solvents emitted from paints have an influence on the human organism, e.g. the induction of hepatic enzymes. This effect was shown in workers exposed to butyl glycol from paints in an electrophoresis painting plant where the exposure value was shown to be less than 0.3 times of the average limit. In these cases D-glucaric acid in urine, which reflects the D-glucarid acid enzyme pathway, was increased. ... 

Neutral solution of esters, glycol ethers, hydrocarbon solvents and smfactants for removing stains originating from paint, lacquer, resin, and adhesives. 

Butyl glycol ethers, the largest volume derivatives of -butyl alcohol used ia solvent appHcations (10), are obtained from the reaction of 1-butanol with ethylene oxide. The most important of these derivatives, 2-butoxyethanol, is used principally ia vinyl and acryHc paints as well as ia lacquers and varnishes. It is also employed ia aqueous cleaners to solubilize organic surfactants. 2-Butoxyethanol [111-76-2] has achieved some growth at the expense of the lower alkoxyethanols (ie, methoxy and ethoxyethanol) because of 2-butoxyethanol s lower toxicity. 

Many similar hydrocarbon duids such as kerosene and other paraffinic and naphthenic mineral oils and vegetable oils such as linseed oil [8001-26-17, com oil, soybean oil [8001-22-7] peanut oil, tall oil [8000-26-4] and castor oil are used as defoamers. Liquid fatty alcohols, acids and esters from other sources and poly(alkylene oxide) derivatives of oils such as ethoxylated rosin oil [68140-17-0] are also used. Organic phosphates (6), such as tributyl phosphate, are valuable defoamers and have particular utiHty in latex paint appHcations. Another important class of hydrocarbon-based defoamer is the acetylenic glycols (7), such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol which are widely used in water-based coatings, agricultural chemicals, and other areas where excellent wetting is needed. 

Transesterification is a crucial step in several industrial processes such as (i) production of higher acrylates from methylmethacrylate (for applications in resins and paints), (ii) polyethene terephthalate (PET) production from dimethyl terephthalate (DMT) and ethene glycol (in polyester manufacturing),... 

Together, antifreeze, PET, and polyester polymers account for about 98% of the ethylene glycol produced in the United States. It is also used sometimes as a deicer for aircraft surfaces. The two hydroxyl groups in the EG molecule also make EG suitable for the manufacture of surfactants and in latex paints. Other applications include hydraulic brake fluid, the manufacture of alkyd resins for surface coatings, and stabilizers for water dispersions of urea-formaldehyde and melamine-formaldehyde The hygroscopic properties (absorbs moisture from the air) make EG useful as a humectant for textile fibers, paper, leather, and adhesives treatment. 

VOCs found in water-based paints in the Netherlands and Denmark (by a survey of manufacturers) are presented in Table 16.3. VOC emission assessments have shown that most of these VOCs are emitted from water-based paints, though with significant variation from product to product in type and quantity of VOC emitted. For example, Table 16.4 presents the VOC emissions from wet products under identical test conditions (Brown, 2000). WBP1 has no 1,2-propylene glycol while the other paints all use large quantities, apparently replacing the glycol ethers and esters. 

Chang et al. (1999) evaluated four USA low-VOC paints in small environmental chambers, in comparison with a conventional water-based paint. All low-VOC paints exhibited TVOC emissions over a 50-hour test period that were at least an order of magnitude lower than that of the conventional paint. VOCs emitted from the low-VOC paints were ethylene glycol, 1,2-propylene glycol, dipropylene glycol,... 

Lundgren et al. (1999) evaluated the field exposures of painters to a low-VOC and a conventional water-based paints in Sweden. They found that exposures to TVOC, 1,2-propylene glycol, acetaldehyde and ammonia were 3-12 times lower for the low-VOC paint, but exposure to formaldehyde (160-180 pgm ) was 3-4 times higher. Brown (2000) reported that emissions from four Australian VOC-free paints included typical aromatic VOCs, dibutyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether and Texanol , though at order of magnitude reduced levels c.f. conventional water-based paints, as well as formaldehyde and benzaldehyde. 

Coalescing agents are, in reality, temporary plasticizers, which promote the coalescence by increasing the amount of plastic flow in latex paints. The types of materials used are ether-alcohol (such as butyl glycol), tributyl phosphate, pine oil, or other strong solvents. All of these have a degree of volatility so that within a period of time they are lost from the film so that the latex hardens to its required properties. 

Table IV shows results from an experimental trial using a Dow Corning experimental IMR agent in an amine extended system. As seen, unlike the three stream trials previously discussed, no additional catalyst needed to be used to produce good RIM parts. The internal release was added directly to the resin side. Forty releases were obtained before the trial was stopped. Release was still good at the time the trial was terminated. Also of note is the excellent retention of physical properties. In addition, initial results with new experimental silicone IMR fluids showed paint adhesion and retention to be good. Table V similarly illustrates results of an experimental two stream fluid in a glycol-extended RIM system. Again, excellent release and physical property retention were observed. With similar levels of this experimental fluid, twenty-five releases have been obtained.

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