Epoxy liners

The epoxy liners in tin cans leach bisphenol A (BPA), an endocrine disruptor, into the food contents. Ingesting even low levels of BPA is a health concern. While BPA-free cans with no epoxy liners are available, they are about 15% more expensive compared to conventional cans. Despite this disadvantage, some canned-food manufacturers have switched to the BPA-free cans. 

There is sufficient credible evidence that BPA leaches out of PC products and epoxy liners into food/beverages in contact with plastic. The critical question is whether potential adverse health impacts are encountered at the low levels of BPA in real exposure environments (as opposed to those in laboratory studies). There may not be enough research information to unequivocally answer the question. 

Centrifugally cast Epoxy, glass-fiber-reinforced Epoxy liner RTRP-21CT RTRP-21CU 10,000 12,500 —... 

Epoxy liners are also applied to renew small-diameter plumbing pipes. This technique was originally developed for the US Navy to renew and rehabilitate deteriorated small-diameter deteriorated piping on naval vessels, ft has since been commercialized for use in residential and commercial structures. The process involves cleaning of the deteriorated piping to remove debris and scale deposits, followed by polymeric coating with epoxy resins and subsequent curing of the epoxy liner. 

Shipment, Storage, and Price. Butynediol, 35% solution, is available in tank cars, tank trailers, and dmms. Stainless steel, nickel, aluminum, glass, and various plastic and epoxy or phenoHc liners have ak been found satisfactory. Rubber hose is suitable for transferring. The solution is nonflammable and freezes at about —5°C. 

Vinyl ester resins generally offer mechanical properties superior to those of polyester matrices but at an increased cost. Vinyl esters are chemically similar to epoxy resins but are manufactured via a cold-curing process similar to that used in the manufacture of polyester resins. Vinyl esters offer superior resistance to water and chemical attack and are used in such appHcations as underground pipes, tank liners, and storage tanks (see Vinyl polymers). 

The thermal stabiUty of epoxy phenol—novolak resins is useful in adhesives, stmctural and electrical laminates, coatings, castings, and encapsulations for elevated temperature service (Table 3). Filament-wound pipe and storage tanks, liners for pumps and other chemical process equipment, and corrosion-resistant coatings are typical appHcations using the chemically resistant properties of epoxy novolak resins. 

Powder Costings. Epoxy-based powder coatings exhibit useful properties such as exceUent adhesion, abrasion resistance, hardness, and chemical resistance. The appHcation possibUities are diverse, including refrigerator liners, oU filters, hospital equipment, primers, shelving, automobUe springs, and fire extinguishers. 

A reaction vessel explosion at BASF s resins plant in Cincinnati (July 19, 1990) killed one and injured 71. The BASF facility manufactures acrylic, alkyd, epoxy, and phenol-formaldehyde resins used as can and paper-cup liner coatings. The explosion occurred when a flammable solvent used to clean a reaction vessel vented into the plant and ignited. The cleaning solvent that was not properly vented to a condenser and separator, blew a pressure seal, and fdled the 80-year-old building with a white vapor cloud. 

This task represents a continuation of efforts to maximize the hydrophobicity of acrylic, epoxy, and other polymeric systems for resistance to water penetration and environmental degradation, and to minimize the dielectric constant and improve the processability for adhesives and coatings, without compromising the necessary structural characteristics for materials used for, e.g., structural elements, liners, paints, and microelectronic devices. 

Epoxy resin has a higher strength at elevated temperatures than polyester resins but is not as resistant to attack by some fluids. Some glass-reinforced epoxy-resin pipe is made with a polyester-resin liner. The coefficient of thermal expansion of glass-reinforced resin pipe is higher than that for carbon steel but much less than that for plastics. 

Silicone release liners are used as a nonadhering surface to which adhesive materials, such as, for example, pressure-sensitive adhesives, can be laminated. UV curable release coatings are based on poly(dimethylsiloxane) oligomers functionalized with acrylate or epoxy groups and are mostly coated onto papers or thin films. 

The advanced applications for nitrocellulose plastisol propellants require that they be integrally bonded to the motor case. Successful case bonding for the multiyear storage life of a rocket calls for special adhesives and liners which are completely compatible with these highly plasticized propellants. Best results have been obtained with a combination of an impervious rubber liner and a crosslinked adhesive system with a limited affinity for the plasticizers used in the propellants. Examples of effective liners are silica-filled butyl rubber and chlorinated synthetic rubber. Epoxy polyamides, isocyanate-crosslinked cellulose esters, and combinations of crosslinked phenol-formaldehyde and polyvinyl formal varnishes have proved to be effective adhesives between propellant and impervious liners. Pressure curing of the propellants helps... 

Tape and film are the most common forms of solid epoxy adhesives. Tape and film are terms that are used rather loosely for adhesives in a thin sheet form. The term tape generally refers to an adhesive that is supported on a web of paper or nonwoven fabric, or on an open-weave scrim of glass, cotton, or nylon. Films, on the other hand, are free of supporting material and consist only of the adhesive. Both tape and film products may be accompanied with a release liner depending on the tack or blocking characteristics of the adhesive. 

The final thickness of epoxy tape or film adhesives is on the order of 5 to 15 mils. These adhesives may be soft and tacky, or stiff and dry, depending on their formulation. The soft and tacky products are valuable in products requiring application to contoured or vertical surfaces. If the product is especially tacky, a release liner (e.g., polyethylene film, coated paper) is generally used to keep the film from blocking. The stiff and dry products are generally used for flat surfaces where speed and ease of application are required. 

Kevlar 29 and versions thereof (K 129 and Kl j.) are also used extensively in lightweight body armor as well as composite liners (with vinylester, polyester or epoxy as the matrix). A quick look at the properties of different Kevlar aramid fibers in Table 4.2 shows why K29 is better than K49 for lightweight body armor applications. K29 has a higher strain to failure than K49. That means that the total work of fracture, i.e. the area under the stress-strain curve, is larger for K29 than K49. Hence, the energy absorbed in the fracture process is higher for K29... 

The liner Is epoxied Into the outer barrel, so you remove it by heating the outer barrel with the torch, expanding it and breaking the epoxy bond. (Epoxy breaks down at about 300 ) Clamp the rear of the barrel in the vise, and use the vise grips or large pliers to slowly twist and pull the outer barrel section off the liner. If it won t turn when heated, go back to the cut, remark the hacksaw blade and find the spot that is not completely cut through. Go easy when removing the outer barrel, it s easy to bend the inner liner. 

The equipment and the experimental procedures using the C02-methanol medium have already been described in previous papers. . For the photoelectrochemical experiments, a stainless steel pressure vessel was equipped with a 2-cm thick quartz window for illumination, p-type InP and GaAs wafers were cut into ca. 0.4 cm x 0.5 cm electrodes and were mounted using epoxy resin. Ohmic contact was made with successive vapor deposition of Zn (30 mn) and Au (100 nm), which was annealed afterward at 425 C in Ar. A silver wire (0.8 mm dia) was used as a quasi-reference electrode (Ag-QRE, ca. +80 mV vs. SCE). A Pt wire (0.8 mm dia) was used as the counter electrode. The photocathode was etched in hot aqua regia for ca. 5 s before each experiment. The electrolyte solution [3 cm, 0.3 mol dm" tetrabutylammonium perchlorate (TBAP) in CH3OH] was placed in a glass cell liner in the stainless steel vessel. Gases were introduced into the pressure vessel and were left to equilibrate for one hour at the desired pressure (1 to 40 atm). 

---