Processing of Binders

The process of binder removal is kept slow to reduce the possibility of macrodefects being produced. Figure 23.15 shows a plot of a binder removal cycle. In this plot a pressurized gas, called a sweep gas, has been passed over the part to help sweep away the vapor. The cycle time also depends on the size of the part. Thin sections take much shorter times than thick sections. The debinding time is proportional to the square of the section thickness of the compact—the familiar parabolic kinetics seen in our discussion of reactions in Chapter 25. 

To measure the hydration heat release process of binder, the auto isothermal calorimeter of TAM Air was used. Tests were conducted using binder of 10 g and w/b ratio of 0.40 and the test temperature was 25 °C. 

Polymers are only marginally important in main memories of semiconductor technology, except for polymeric resist films used for chip production. For optical mass memories, however, they are important or even indispensable, being used as substrate material (in WORM, EOD) or for both substrate material and the memory layer (in CD-ROM). Peripheral uses of polymers in the manufacturing process of optical storage media are, eg, as binder for dye-in-polymer layers or as surfacing layers, protective overcoatings, uv-resist films, photopolymerization lacquers for repHcation, etc. 

Binders and Resins. The choice of binder is the most important ingredient choice in the formulation process because the binder affects the performance properties of a paint more than any other single ingredient (3). The physical properties of binders required for paints include the abiHty to dry or cure under various ambient conditions, good adhesion to various substrates, abrasion resistance, washabiHty, flexibiHty, water resistance, and ultraviolet light resistance. The balance of these required properties is mosdy dependent on whether the paint is being developed for interior or exterior appHcations. 

Reclaimed mbber, which is widely used in dry mbber, has Htde use in latex compounding. A dispersion or artificial latex of the red aim must be made by a rather expensive process of milling in dispersing agents, eg, soaps and casein, and water. Some reclaim dispersions are used in latex compounds for such things as spread mbber goods and adhesives and fiber binders to reduce cost. However, for most latex compounds, it is not desirable because of the poor physical properties it imparts and the resultant darkening of the compound. 

A three-step nitration process of toluene is described. The advantages of the modified process are reduced waste, less hazardous operation, reduced oleum requirement, partial replacement of coned HN03 with dil HN03, and higher rate of toluene flow into the reactor (Ref 86) The continuous process of H.C. Prime (Ref 73) for preparing TNT was studied by thin-layer chromatography on silica gel with a starch binder and a fluorescent indicator. The nitration... 

Warm-box process. The binder, 1.3 to 1.5% of sand weight, is a reactive, high FA binder. The catalyst, 20% of sand weight, is usually a copper salt of sulfonic acid. Sand, binder, and catalyst are mixed and blown into a heated core box. The heat activates the catalyst, which causes the binder to cure. Curing time is 10 to 30 s depending on thickness. The final tensile strength can be 3000 to 4000 kPa (400 to 600 psi). 

Splitting up the total amount of degraded paint material into a percentage of pigment and a percentage of binder. Gravimetric analysis of the destruction process enables the mass loss to be... 

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