Foaming Method

Chemical binders are appHed to webs in amounts ranging from about 5 to 60 wt %. In some instances when clays (qv) or other weight additives ate included, add-on levels can approach or even exceed the weight of the web. Waterborne binders ate appHed by spray, saturation, print, and foam methods. A general objective of each method is to apply the binder material in a manner sufficient to interlock the fibers and provide chemical and mechanical properties sufficient for the intended use of the fabfic. 

Principle The adsorptive-bubble separation methods, or adsub-ble methods for short [Lemlich, Chem. Eng. 73(21), 7 (1966)], are based on the selective adsorption or attachment of material on the surfaces of gas bubbles passing through a solution or suspension. In most of the methods, the bubbles rise to form a foam or froth which carries the material off overhead. Thus the material (desirable or undesirable) is removed from the liquid, and not vice versa as in, say, filtration. Accordingly, the foaming methods appear to be particularly (although not exclusively) suited to the remov of small amounts of material from large volumes of hquid. 

The foaming methods vary widely. One approach is to whip air into suspension or a solution of the plastic, which is then hardened by heat curing. A second is to dissolve a gas... 

Foaming methods vary widely. One is to whip air into suspension or a solution of the plastic, which is then hardened by heat curing. A second is to dissolve a gas in a mix, then expand it when the pressure is reduced. Another is to heat a mixture until one of its liquid components volatilizes. Similarly, water produced in an exothermic chemical reaction can be volatilized within the mass by the heat of reaction. A different technique uses a chemical reaction to produce carbon dioxide gas within solid mass. A related way is for a gas such as nitrogen to be... 

Softener/napping assistant providing a soft, sliky, silicone-type hand with slight scroop without the aid of silicone. Applied by pad or foam methods for synthetic and natural fibers and their blends. 

Slabstock Production, Slabstock rigid foams are produced continuously by using a horizontal-conveyor-type machine which is similar in principle to Figure 7. In contrast, discontinuous production is carried out by using a box. The box-foaming method is not efficient, but it is suitable for small-scale production of various foams with low investment cost. Slabstock foam and box-foaming foam are used for the production of insulation boards, pipe coverings and many other insulation materials. 

The commercialization of simUar foams was followed by Hexaform (trade name ICl) in 1968 (57). The commercialization was later followed by Upjohn Company (trade name Kode 25) and Jim Walter Corp. (trade name Thermax). Foaming methods of modified-isocyanurate foams include slabstock, laminate, block, pour-in-place and spraying. 

E.l. DuPont de Nemours Co., Inc., Elastomer Chemicals Div., Wilmington, Delaware, "Rigid Urethane Foams — Methods of Application", Bulletin A-4713, (June 1957). 

This brief summary report describes the state of the art of all types of cellular materials, particularly plastics and elastomers. The report is organized in the form of a handbook and has an Introduction and sections on Types of Foams (Cellular Materials), Methods of Manufacture, Foam Properties, Solvent Cementing and Adhesive Bonding of Foams, Methods of Making Foams Conductive, and Applications. There are two Appendices, one on Standardization Documents (Test Methods, Practices and Specifications) and the other on Definitions. 

The degumming of silk can also be carried out by foam method. The silk skiens are subjected to the action of foam from a boiling soap bath. Skiens are actually hung above the soap solution and the foam action has a tendency to dissolve and eliminate sericin. This method, however, is not popularly adopted. 

In the study by Bocharov and Krasovskij [305], the concentration Cm for maximum surfactant adsorption at the water/air interface and the maximum permissible concentration (MPC) of surfactants present in household waters are compared and a large table of data given. For example, for sodium alkyl sulfates, the MPC and Cm values, respectively, are 0.5 and 0.6 0.1 for dodecyl benzene sulfonate 0.5 and 0.4 0.1. For nonionics R(OC2H4)OH, where R=aliphatic radical and n = ethoxy groups number, these values are for R=C]o- Ci3/n=7 0.1 and 0.12 0.3 for R=Cio- Ci8/n=10 0.1 and 0.10 0.02. Thus, adsorption isotherm studies are very promising for the determination of MPC in comparison with the frequently applied foaming method where the MPC is determined at a concentration where dynamic foam bubbles appear in the waste water. 

Tissue Integration Drip casting Starch consolidation Polymeric sponge method Foaming method Organic additives Gel casting Slip casting... 

Figure 2.37 Expendable polystyrene pattern (r.) for the Lost Foam process and an example of a casting produced by the Lost Foam method (1.)...

Figure 8. Fracture surface of lightweight CaZP ceramic made by the saturated polymer foam method using coarse powders...

Hsu Y-Y, Gresser JD, Stewart RR et al (1996) Mechanisms of isoniazid release frtnn poly (d, L-lactide-co-glycolide) matrices prepared by dry-mixing and low density polymeric foam methods. J Pharm Sci 85 706-713... 

---