Foam thermal insulation

A stndy was made of the effects of foam formulation and process conditions and liner composition on the adhesion of HCFC-141b blown rigid PU foam thermal insulation to refrigerator liner protective layers made of ABS, high-impact PS (HIPS), PE and blends of HIPS and PE containing a compatibiliser and adhesion promoter. A tensile test was used to quantify the level of adhesion before and after thermal cycling, and the Brett mould was used for laboratory simulations of foam adhesion within... 

Part 1 1989. Sprayed Foam Thermal Insulation Applied Externally, 9 pp... 

Use Packaging, refrigerator doors, air-conditioner cases, containers and molded household wares, machine housings, electrical equipment, toys, clock and radio cabinets. Foam Thermal insulations, light construction (as in boats, etc.), ice buckets, water coolers, fillers in shipping containers, furniture construction. Spheres Radiator leak stopper. 

Basopor . [BASF AG] Urea-f( inalde-hyde resin precondensate for prod of synthetic urea-formaldehyde resin foam, thermal insulation in ctmstruc-tion, protection i ainst explosiois in mining. 

Figure 8. Aryloxyphosphazene elastomers (APN) offer excellent potential for applications such as A, closed cell foam thermal insulation with high fire retadancy and low smoke generation (32.34) B, pigmented APN coatings in aluminum substrates with low flanmablllty, low flame spread, and low smoke (35) C, APN Insulation and cable Jacketing (36) D, open cell APN comfort cushioning (37). Photograph courtesy of Firestone Tire and Rubber Company ( ).

Taylor, Naval Ship RAD Center, Annapolis, MD 1978, NASA TM-78523, N79-12029 Wldenor, W. M. "Polyphosphazene Foam Thermal Insulation" 1981, DTNSRDC TM-28-81-324. 

Disposable cups and glasses for hot (only PS foam) and cold drinks, electrical fittings, CD case (jewel box), Airfix model kits, food containers, coat hangers, hair combs, TV cabinets, expanded foam packaging, foam thermal insulation, foam ceiling tiles, insulated food containers. 

The development of foam-insulated cryogenic containment piping was undertaken to achieve lower costs and to improve reliability. It was estimated that the foam thermal insulation would increase the low-temperature refrigeration load caused by heat transfer from the surrounding soil by an additional 49.7 kW/km (80 kW/mi) for a 3500-MVA cable system. This increase can be partially offset by... 

Fig. 1. Cable concept based upon foam thermal insulation.

Foam thermal insulation was selected for the cable pipe because of its low cost and high reliability, as demonstrated by its use in LNG piping systems. Possible degradation of its insulating quality could be caused by the infiltration of water... 

Fidler, C. (W. S., PA), and C.S. Thomas (Willow Street, PA). 1996. Aerogel-in-foam thermal insulation and its preparation. United States Armstrong World Industries, Inc. (Lancaster, PA). 

Fidler, C., and T.C. Simonton. 1996. Aerogel-in-foam Thermal Insulation and its Preparation. 

Polyurethane. SmaU quantities of polyurethane film are produced as a tough mbber-like film. Polyurethane is more commonly used to produce foamed sheet, both flexible and rigid. The flexible foam is used as cushioning in furniture and bedding the rigid foam is widely used for architectural insulation because of its outstanding thermal insulation efficiency (see Urethane POLYMERS). 

MoistureResista.nce, Plastic foams are advantageous compared to other thermal insulations in several appHcations where they are exposed to moisture pickup, particularly when subjected to a combination of thermal and moisture gradients. In some cases the foams are exposed to freeze—thaw cycles as well. The behavior of plastic foams has been studied under laboratory conditions simulating these use conditions as well as under the actual use conditions. 

Other. Because a foam consists of many small, trapped gas bubbles, it can be very effective as a thermal insulator. Usually soHd foams are used for insulation purposes, but there are some instances where Hquid foams also find uses for insulation (see Eoamed plastics Insulation, thermal). Eor example, it is possible to apply and remove the insulation simply by forming or coUapsing the foam, providing additional control of the insulation process. Another novel use that is being explored is the potential of absorbing much of the pressure produced by an explosion. The energy in the shock wave is first partially absorbed by breaking the bubbles into very small droplets, and then further absorbed as the droplets are evaporated (53). 

A low (<0.4 W / (m-K)) thermal conductivity polymer, fabricated iato alow density foam consisting of a multitude of tiny closed ceUs, provides good thermal performance. CeUular plastic thermal insulation can be used in the 4—350 K temperature range. CeUular plastic materials have been developed in... 

Flame Resistance. Traditionally, small-scale laboratory flammabiUty tests have been used to initially characterize foams (38). However, these do not reflect the performance of such materials in bulk form. Fire characteristics of thermal insulations for building appHcations are generally reported in the form of quaHtative or semiquantitative results from ASTM E84 or similar tunnel tests (39). Similar larger scale tests are used for aircraft and marine appHcations. 

Extruded Rigid Foa.m. In addition to low temperature thermal insulation, foamed PSs are used for insulation against ambient temperatures in the form of perimeter insulation and insulation under floors and in walls and roofs. The upside-down roof system has been patented (256), in which foamed plastic such as Styrofoam (Dow) plastic foam is appHed above the tar-paper vapor seal, thereby protecting the tar paper from extreme thermal stresses that cause cracking. The foam is covered with gravel or some other wear-resistant topping (see Roofing materials). 

Foams. Sulfur can be foamed into a lightweight insulation that compares favorably with many organic foams and other insulating materials used in constmction. It has been evaluated as thermal insulation for highways and other appHcations to prevent frost damage (63) (see Eoamed plastics Insulation, thermal). 

Polyurethane. Polyurethanes (pu) are predominantly thermosets. The preparation processes for polyurethane foams have several steps (see Urethane polymers) and many variations that lead to products of widely differing properties. Polyurethane foams can have quite low thermal conductivity values, among the lowest of all types of thermal insulation, and have replaced polystyrene and glass fiber as insulation in refrigeration. The sprayed-on foam can be appHed to walls, roofs, tanks, and pipes, and between walls or surfacing materials directly. The slabs can be used as insulation in the usual ways. 

Thermal Insulation. Foamed plastics (qv) are used as thermal insulation for aU types of constmction because of their low heat- and moisture-transmission values. Polystyrene is used either as foamed board or expandable beads. The foam may be faced with a stmctural surfacing material, eg, a kraft liner-board, to form a panel for insulating mobile homes. These foams can dupHcate the appearance of wood and be used as trim. Foams can also be used as backing, for example, on aluminum siding, to provide heat and sound insulation. Foamed beads can be incorporated in concrete to reduce its density and provide some thermal insulation. 

Finishes Thermal insulations require an external covering (finish) to provide protection against entry of water or process fluids, mechanical damage, and ultraviolet degradation of foamed materials. In some cases the finish can reduce the flame-spread rating and/or provide fire protection. 

Foam Insulation Since foams are not homogeneous materials, their apparent thermal conductivity is dependent upon the bulk density of tne insulation, the gas used to foam the insulation, and the mean temperature of the insulation. Heat conduction through a foam is determined by convection and radiation within the cells and by conduction in the solid structure. Evacuation of a foam is effective in reducing its thermal conductivity, indicating a partially open cellular structure, but the resulting values are stiU considerably higher than either multilayer or evacuated powder insulations. 

The specific heats of polymers are large - typically 5 times more than those of metals when measured per kg. When measured per m, however, they are about the same because of the large differences in density. The coefficients of thermal expansion of polymers are enormous, 10 to 100 times larger than those of metals. This can lead to problems of thermal stress when polymers and metals are joined. And the thermal conductivities are small, 100 to 1000 times smaller than those of metals. This makes polymers attractive for thermal insulation, particularly when foamed. 

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