Resilient cushion

Resilient materials will undergo a degree of impression or compression according to the nature of the material, the force involved and the area of contact taking the force. The way the resilient material compresses will also depend on how it acts as a resilient or non-resilient cushion , i.e. at one end of the scale it may compress and have 100% recovery when the force is... 

Adhesive-coated expanded PS shapes have been used as an alternative to foam-inplace polyurethane systems (see Section 13.1.3). The shapes are deposited into a corrugated box, covered with a release film, the product added, another sheet of release film put in place, and the carton filled with the adhesive-coated shapes. When the water-based adhesive dries, a pair of resilient cushions surrounds the product. 

Three different rubber compounds are required for use in the above construction of a V-belt (1) a base compound, which is the major constituent on a weight basis, (2) a soft and resilient cushion compound required for surrounding and protecting the reinforcing cord assembly, and (3) a friction compound used for rubberizing the fabric casing of the belt (see Appendix AlO). 

When the machine is properly leveled and aligned, some vibration is reduced because gears mesh better, shafts run truer, and slides travel more smoothly along the gibs. Additionally, the resilient cushion of the isolator will not only make it easier to level the machine, but it will also markedly reduce impact, impact reaction forces, and transmission of vibration. 

To optimize the effectiveness of the isolator, its resilient cushion should be designed and applied to provide maximum vibration control without compro-... 

Unmodified Modified Sheet Standard cushioning Carpet underlay High resilience type PVC b Liquid Sheet ... 

Resilience of textile fabrics when compressed in the bent state is related to wrinkle resistance and retention of shape, drape, and hand. Resilience is an important parameter for evaluating blankets, wearing apparel in which warmth is a factor, pUe fabrics including carpets, and bulk fiber utilization in mattresses, cushions, etc. The general method for determining compressional resilience is to compress and unload the material cycHcahy, creating a plot of compressive force versus fabric thickness. 

Tissue Conditioners. Tissue conditioners are gels designed to alleviate the discomfort from soft-tissue injury, eg, extractions. Under a load, they exhibit viscous flow, forming a soft cushion between the hard denture and the oral tissues. The polymer in tissue conditioners is often the same as that used for resilient liners. The liquid is a plasticizer containing an alcohol of low volatility (219,220). 

The alcohol swells the poly (ethyl methacrylate) beads, rapidly promoting diffusion of the plasticizer into the polymer. As a result of the polymer-chain entanglement, a gel is formed. The conditioner is applied to the denture and provides a cushioning effect alcohol and plasticizer are slowly leached out, and the material becomes rigid. To ensure resiliency, the conditioner must be replaced after a few days. Some materials exhibit high flow over a short period compared with others with low initial flow the latter remain active longer. 

There is also growing interest in multi-phase systems in which hard phase materials are dispersed in softer polyether diols. Such hard phase materials include polyureas, rigid polyurethanes and urea melamine formaldehyde condensates. Some of these materials yield high-resilience foams with load deflection characteristics claimed to be more satisfactory for cushioning as well as in some cases improving heat resistance and flame retardancy. 

By crosslinking, the viscosity of EVA at high temperatures is increased and the individual cells are kept in a stable condition without rupture or agglomeration. A low density microcellular foam can be thus obtained. By selecting the vinyl acetate content, the EVA foam is flexible and highly resilient with easy coloring and adherent to other materials. The application is used widely in shoe soles, sandals and cushion materials. 

Extruded low density foam produced I nim I.DI E is a tough, flexible, and resilient closed-celled foam used in a wide variety of applications such as cushion packaging and safety components. 

Cross-linked polyethylene foams are produced by eilher radiation or chemical cross-linking of an extruded expandable sheet containing a chemical blowing agent. These products have finer texture and a softer, more resilient feel than extruded low density polyethylene foams and are used in comfort cushioning and cushion packaging applicutinns. 

Molded flexible foam products are becoming more popular. The bulk of the molded flexible urethane foam is employed in the transportation industry, where it is highly suitable for die manufacture of seat cushions, back cushions, and bucket-seat padding. TDl prepolymers were used in flexible foam molding in conjunction with polyether polyols. The need for heat curing has been eliminated by the development of cold-molded or high resiliency foams. 

Put the foundation plate in its place and make certain that it lies steadily. Check that the anchor screws do not press against the edges of the holes in the plate, as they would otherwise prevent the resilient mounting of the plate between the rubber cushions. 

Flexible foam is made from long-chain diols with a small amount of triols for cross-linking to give strength and resilience. Foaming is produced by reaction between measured amounts of isocyanate and water to liberate carbon dioxide. Molded products are made by pouring the reactive liquid mixture into a mold cavity at 50°C. They foam and cure in 2-10 min, after which they are temporarily crushed or vacuum-shocked to open the cell walls and insure softness. Then they are allowed to condition for several hours to finish the cure. The major products are auto seating and headrests, and furniture cushions. 

Expanded polystyrene loose-fill is used in many markets today. The most common are dunnage (used to fill up space in a shipping box), cushioning (where the resilient qualities of the polystyrene foam are used), and texturizer, where it is ground into smaller particles and used in making textured ceilings in commercial and residential buildings. 

Federal Specification PP-C-1797A, "Cushioning Material, Resilient, Low Density, Unicellular, Polypropylene Foam," 1 September 1982. This specification supersedes the earlier Military Specification M1L-C-81823(AS) (1971). 

MIL-C-26861C Cushioning Material, Resilient Type, General, 9 June 1988, 22 pp (FSG 8135) (69)... 

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