Foamed latex rubber

Whipping air into a colloidal-resin su ension and then gelling the porous mass. This is how foamed latex rubber is made. 

Foams are used industrially and are important in rubber preparations (foamed-latex) and in fire fighting. The foam floats as a continuous layer across the burning surface, so preventing the evolution of inflammable vapours. Foams are also used in gas absorption and in the separation of proteins from biological fluids. See anti-foaming agents. 

Mechanical whipping of polymers in a liquid form and subsequent setting in the whipped state. The manufacture of latex rubber foam is the best-known example of this approach. 

In suspension processes the fate of the continuous liquid phase and the associated control of the stabilisation and destabilisation of the system are the most important considerations. Many polymers occur in latex form, i.e. as polymer particles of diameter of the order of 1 p.m suspended in a liquid, usually aqueous, medium. Such latices are widely used to produce latex foams, elastic thread, dipped latex rubber goods, emulsion paints and paper additives. In the manufacture and use of such products it is important that premature destabilisation of the latex does not occur but that such destabilisation occurs in a controlled and appropriate manner at the relevant stage in processing. Such control of stability is based on the general precepts of colloid science. As with products from solvent processes diffusion distances for the liquid phase must be kept short furthermore, care has to be taken that the drying rates are not such that a skin of very low permeability is formed whilst there remains undesirable liquid in the mass of the polymer. For most applications it is desirable that destabilisation leads to a coherent film (or spongy mass in the case of foams) of polymers. To achieve this the of the latex compound should not be above ambient temperature so that at such temperatures intermolecular diffusion of the polymer molecules can occur. 

Ethylamine is primarily used in the production of triazine herbicides. Ethylamine has also found use in resin chemistry, oil refining, and solvent extraction as a stabilizer for latex rubber and in the manufacture of dyestuffs, medicinals, corrosion inhibitors, urethane foam catalysts, and agents used in wash-and-wear fabrics. 

When making a large article such as a mattress, a metal mold may be filled with the foamed latex and heated by steam at atmospheric pressure. After removing the foamed rubber article from the mold, it may be dewatered by compressing it between rolls or by centrifuging and by drying with hot air in a tunnel dryer. In foamed rubber formulation a part of the NR latex can be replaced by a synthetic rubber latex. One such combination is shown in Table 2.3. 

Chem. Descrip. Blend of microcrystalline wax and paraffin wax Uses Processing aid in latex foams antiozonant in latex rubber for use in paper and wood coatings, sizing, textile lubrication Properties Wh. emulsion m.p. 150 F pH 8.5-9.5 52-54% solids Octowax695 [Tiarco]... 

Uses Cement admixture elastomeric textile thread adhesives (cold-sealable pkg., selfsealing envelopes, leather/tile adhesives, pressure-sensitive) binder for tufted carpet anchor coatings, flock attachment, nonwoven fabrics carpet foam backings dampproofing formulations latex dipping compds. (gloves, contraceptives, balloons) molded latex foam natural rubber castings rubberized hair prods. in food-pkg. adhesives and pressure-sensitive adhesives... 

Latex rubber foams are generally prepared in slab or molded forms in the density range 64-128 kg/m (4-8 Ib/ft ). Synthetic SBR latexes have replaced natural rubber latexes as the largest-volume raw material for latex foam rubber. Other elastomers used in significant quantities are polychloroprene, nitrile rubbers, and synthetic cfs-polyisoprene (116). 

Tensile Strength and Elongation. The tensile strength of latex rubber foam has been shown to depend on the density of the foam (159,180) and on the tensile strength of the parent rubber (180,181). At low densities the tensile modulus approximates a linear relation with density bnt increases with a higher power of density at higher densities. Similar relations hold for polyurethane and other flexible foams (166,182,183). 

The tensile elongation of solid latex rubber has been shown to correlate well with the elongation of foam from the latex (181). The elongation of flexible polyurethane has been related to cell structure (183,184). 

Applications. Flexible cellular poly(vinyl chloride) was developed as a comfort-cushioning material with compression-deflection behavior similar to latex rubber foam, and with the added feature of flame retardancy (37). It has a... 

Uses Foaming agent for gelled natural/SBR latex rubber foams... 

Uses Pigment softener/dispersant antifog, foam booster/stabilizer, wetting agent in alkaline paint strippers, latex emulsions, latex rubber reclamation, inks, piastic films, cosmetics cooling tower corrosion inhibitor... 

Empicol LX28 Empicol LZ FR-25 Sodium lauryl suKMe foam builder, foam rubber latexes Disodium cocoyl sulfosuccinamate Disodium N-oisyi suifosuccinamate foam builder, foamable precoats STEPANOL LCP-E foam builder, foamed latexes Aerosol 18... 

L tex Foa.m Rubber. Latex foam mbber was the first ceUular polymer to be produced by frothing. (/) A gas is dispersed in a suitable latex 2) the mbber latex particles are caused to coalesce and form a continuous mbber phase in the water phase (7) the aqueous soap film breaks owing to... 

Rubber processed in latex form accounts for about 10% of new mbber consumption. Rubber latex is a Hquid, oil-in-water emulsion which is used to make foam or thin-walled mbber articles. The same accelerators and antidegradants used in dry mbber are used in latex, with longer-chain versions preferred for greater oil solubiHty. To prepare these and other additives for addition to latex, they must be predispersed in water and the surface of the powder or oil droplet coated with a surface-active agent to prevent destabilization (coagulation) of the latex. 

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