Through-air bonding

The ADL is very important to provide a sense of dryness to the skin, providing additional separation between the wet pad and the skin. ADLs should be used whenever the mix of SAP in the absorbent core exceeds about 15% by weight or when the liquid penetration time requires a boost in order to avoid diaper leakage due to liquid accumulation inside the diaper. ADLs are made either of through air bond nonwovens, curly fibres such as in P G s pampers and some Ontex diapers, or some kind of highloft nonwoven. An aperture film, made of perforated plastic film, has also been used successfully in some markets. Lower priced diapers sometimes use resin-bonded nonwovens, but they do not work as well. 

The surface of the product particles is covered with organic moieties attached through covalent bonding. The organic moieties can be eliminated by heat treatment at 250 to 300°C in an air flow. 

Thiol monolayers are not removed by solvents, but by sulfur-active chemicals which pass through the surface monolayers. Laser desorption mass spectrometry has shown that thiolate molecules are intact on the gold surface, but through air oxidation, some sulfonates develop. The relative stability of alkanethiol SAMs on gold to air oxidation is to be expected due to the covalent nature of the S—Au bond. Photooxidation via UV excitation of electrons in the metal surface is, however, possible and leads to sulfonate salts which have again been characterized by mass spectrometry as well as by XPS . Alkene-thiolate monolayers can best be desorbed from gold by a one-electron reductive path. Stable monolayers on gold were also obtained with benzenesulfinate. 

V(AB) nuclear spin-spin coupling constant, through n bonds between A and B JANAF Joint Army-Navy-Air Force... 

When the metal is bonded through nonoxygen bonds the results in air are such that initial degradation may involve any number of pathways and sites and is dependent on the particular polymer. 

Another case which involved a general warning which failed to take proper account of all aspects of a product s vapors was Tucson Industries, Inc. v. Schwartz. " In this case, the plaintiffs eyes were severely damaged and partially blinded by fumes from a cement being used to bond tops onto tables in a room adjacent to the plaintiffs office. The cement had been labeled to warn of its flammability and the toxicity of its vapors. The harmful fumes reached the plaintiff by traveling through air conditioning ducts. 

PROBABLE FATE photolysis . C-Cl bond photolysis can occur, not important in aquatic organisms, photooxidation half-life in air 9,24-92.4 hrs, reported to photodegrade in water in spite of the lack of a photoreactive center oxidation-, not an important process hydrolysis . very slow, not important, first-order hydrolytic half-life 207 days, reaction with hydroxyl radicals in atmosphere has a half-life of 2.3 days volatilization may be an important process, however, information is contradictory, volatilization half-life from a model river 6 days, half-life from a model pond considering effects of adsorption 500 days, slow volatilization from water is expected with a rate dependent upon the rate of diffusion through air sorption important for transport to anaerobic sediments biological processes biodegradation is important occurs slowly in aerobic conditions, occurs quickly and extensively in anaerobic conditions... 

Figure 11 Light path of the IR beam within a bonded silicon wafer pair used in the multiple internal transmission method. The IR radiation is totally reflected at the outer Si/air surfaces and tunnels repeatedly through the bonding interface.

Powder bonded non-woven n A manufactured product in which a carded web is produced and treated with a thermoplastic powder that has a melting point less than that of the fiber in the web. The powder is heated to its melting point by through-air and infrared heating or by hot-calendering to effect bonding. 

Flame lamination is another hot-air bonding process that is used mainly to continuously join fabric to foam. A foam sheet is passed over an open flame to create a thin layer of molten polymer on the foam surface, which is then mated with a fabric by passing the assembly through a set of rollers (Figure 13.5). The molten foam surface acts as an adhesive when it cools. PU foam is the most frequently used material in flame lamination. 

---