Adhesion powders

General-purpose powder adhesive Parts by weight... 

Powder adhesives are generally one-part, epoxy-based systems that do not require metering and mixing but often must be refrigerated for an extended shelf life. Elastomeric... 

Electric light bulb and mating socket Cardboard or heavy paper Black Powder Adhesive tape... 

Podczeck, F. Investigations into the reduction of powder adhesion to stainless steel surfaces by surface modification to aid capsule filling. Int. J. Pharm. 1999, 178, 93-100. 

Sendall, F.E.J. Staniforth, J.N. A study of powder adhesion to metal surfaces during compression of effervescent pharmaceutical tablets. J. Pharm. Pharmacol. 1986, 38, 489-493. 

Use Manufacture of nylon and of polyurethane foams preparation of esters for use as plasticizers and lubricants food additive (acidulant) baking powders adhesives. 

Kasolv . [PQCotp.] Hydrous potassium silicate powders adhesives, binders, surfactants, coagulants, flocculants, emulsifiers, dispersants, soil antiredeposition agents, corrosion inhibitors. 

Stage micrometer Polishing cloths and powders Adhesive-backed grinding papers... 

The JKR theory was developed in the early 1970s to account for the adhesion between spherical bodies, especially fine particles (see Powder Adhesion), making elastic contact. Previously, most studies of elastic contacts had presumed that bodies like steel railway wheels behaved as though adhesion was zero. In other words, no adhesion interaction seemed to be acting in most engineering contact situations. Negligible adhesion force is generally detected as a wheel is lifted from a rail, and the size of the contact spot between wheel and rail can usually be predicted accurately from the laws of elastic deformation, without any molecular attractive forces. 

Such understanding and control of particle adhesion is essential to many industrial processes. For example, powder adhesion is useful in making pharmaceutical tablets, which are manufactured by compressing the powder in shaped steel dies. Polymer powders... 

Fig. 1. (a) Shear box test for powder adhesion and friction (b) plot of shear force versus load for a fine powder... 

In contrast, particle adhesion can be a problem in certain areas powders may refuse to flow out of hoppers, pigments may form intractable sediments in paints and dust grains may wreck electronic micro-circuitry by adhering strongly to the chips. Perhaps the most dramatic consequences of problematic particle adhesion are found during earthquakes or mudslides, when the relatively weak interparticle forces are overcome by vibration or by fluid flow. The theory of powder adhesion attempts to describe and predict snch problems from first principles. 

Powder adhesion K KENDALL Adhesion between fine powder particles practical consequences... 

After depositing the charged powder on the paper (see Fig. XII.S.c), the charges may leak off so that the powder adhesion will become weaker. Hence it is necessary to fix the deposited powder this can be done by heating, by applying pressure, or by using a solvent. When heating is used, the adherent powder particles are fused and thus fixed on the paper. A solvent vapor (acetone, carbon tetrachloride, diethyl ether, etc.) will partially dissolve and also fix the toner particles on the paper. 

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