Sound deadening

Lightweight concrete is made from prefoamed EPS beads, Pordand cement, and organic binders. Precast shapes ate being used to provide stmctural strength, thermal insulation, and sound deadening. 

EiaaHy, a new aluminum fire-resistant paneling consists of a composite design that iacludes a soHd thermoplastic compound core covered with a high density polyethylene adhesive film and an aluminum skin. The product is easily formable. It has sound deadening abiHties, and an optional poly(vinyHdene fluoride) resia coatiag provides damage resistance. 

These price and property ranges do not include fine retardant grades or highly filled materials for sound deadening. Shore A or D as indicated. 

Large amounts of iaert fillers, such as whiting, talc, and clays, can be added. Very dense fillers, such as barium or strontium sulfates, are used to make compounds intended for sound-deadening appHcations. In contrast, high levels of reinforcing fillers, such as carbon black, produce undesirable properties ia the final product. 

Compounds based on S—EB—S usually contain polypropylene, which improves solvent resistance and processibiUty and raises upper service temperatures. Compounds intended for use in the automotive industry are able to survive 1000 hours air exposure at temperatures of 125°C with only minor changes in properties (54). Very soft compounds have been developed to replace foam mbber for interior trim parts. In this and similar appHcations, these soft compounds are usually insert molded over polypropylene or metal and then coated with flexible polyurethane paint (55). Other automotive appHcations include products intended for sound deadening, flexible air ducts, and gear shifter boots, as weU as improving the properties of sheet mol ding compounds. 

These cross-linked cellular materials have been used in the automotive industry for carpeting, boot mats and sound deadening. They have also found use for pipe insulation and as flotation media for oil-carrying and dredging hose. 

Polyimides and related materials have also been used in a number of specialist applications. Polyimide foams (Skybond by Monsanto) have been used for the sound deadening of jet engines. Polyimide fibres have been produced by Rhone-Poulenc (Kermel) and by Upjohn. 

Pressure-sensitive adhesives (PSAs) based on acrylic, natural rubber and silicone are employed primarily for ease of application. To name Just a few applications, PSAs bond decals to surfaces, interior decorative surfaces to interior panels, interior trim pieces in place directly or hook and loop tape for the same purpose, structural shims in place during manufacturing and acoustic (sound deadening) materials to body skin interior surfaces. Tape products with pressure-sensitive adhesive on one or both surfaces are used for such functions as cargo compartment sealing, as a fluid barrier to prevent spills and leaks in the lavatories and... 

Thermoplastics which are used for corrosion protection can be applied in coatings as thin as 0.025 mm by solution techniques and in excess of 5 mm by extrusion or plastisol dipping. They are used where environmental resistance, chemical resistance, abrasion resistance, sound deadening or cushioning are required. They are used in those market areas that necessitate metallic mechanical strength plus thermoplastic corrosion resistance. 

Sound-deadening material is used to make door and drawer operation quieter than formerly. One manufacturer features drawer fronts of molded plastic, which makes it possible to have the handles recessed. 

Hot-melt spray adhesives will bond successfully carpets, fabrics, laminating panels, metals (both painted and unpainted), and both polyethylene and polypropylene film and sheet. Two important commercial uses at the time of writing are bonding sleeves of low-density polyethylene to ductile iron pipes and bonding sound-deadening materials and carpets to the floors of motor cars. 

The two major classifications for RIM products are (1) high-density, high-modulus, flexible elastomers and (2) low-density structural foams. Automotive trim and fascia are usually elastomers. Furniture and equipment housings are frequently molded as structural foams (especially when texture and/or sound deadening are included in the product specifications). 

The mechanical foaming of PVC pastes has been carried out for some time on the basis of air or gas being whisked into specially formulated plastisols, which are cured using microwave or infrared ovens. The lightweight material is used for sound deadening or domestic applications. There has been a relationship established between the effects of residual emulsifier in the E-PVC resin grade and foaming behaviour (101). 

Use High-temperature insulation of kilns and furnaces, packing expansion joints, heating elements, burner blocks rolls for roller hearth furnaces and piping fine filtration insulating electrical wire and motors insulating jet motors sound deadening. 

Some other major uses, by types, are as follows Solvent cutback and water emulsion, nonfibrated coatings are used as protective coatings for metal and masonry. Solvent cutback and water emulsion, fibrated coatings are used in roofing, waterproofing, and industrial insulation, and in automobiles for protection and sound deadening. 

Table VIII. Asphalt Coatings and Sound Deadeners for Transportation Vehicles... 

Astra Bar. [ECXIIntT.] Barium sulfate rubber additive imparts high density, chemical inertness, sound deadening, chemical resistance. 

USE Bottle stoppers, sound deadeners, heat insulators, life preservers, gaskets, linoleum manufacture, cork tile, bulletin boards, dart boards, inlays for shoes. 

Figure 2.11 shows a natural draft burner without an air inlet muffler. These burners are often quiet enough that no muffler is needed. Figure 2.12 shows a common type of muffler used on a natural draft burner used in the floor of refinery heaters where the air inlet has a baffle lined with sound-deadening insulation. Figure 2.13 shows a comparable standard muffler for a radiant wall burner... 

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