MXPA01000544A - Flame retardant microporous polymeric foams - Google Patents

Abstract

Disclosed are microporous, open-celled polymeric foams formed by polymerizing a high internal phase water-in-oil emulsion comprising a continuous oil phase and discontinuous water phase where the foam has a Limiting Oxygen Index (LOI) value of at least about 18%. Such foams are commonly known in the art as"HIPEs". The foams have a variety of flame retardant applications, including use in insulation.

Description

POLYMERIC FOAMS RETARDANT FIRE MICROORPOSE FIELD OF THE INVENTION This application relates to microporous open cell polymeric foams which are resistant to combustion.

BACKGROUND OF THE INVENTION The development of microporous foams has been subject to substantial commercial interest. The properties of these foams can be varied to the advantage of applications that vary from thermal, acoustic, electrical and mechanical (for example, damping), insulators, absorbent materials, filters, carriers for inks, dyes, lubricants and lotions, to make profitable articles and similar. References describing such uses and properties of foams include Oertel, G. "Polyurethane Handbook" Hanser Publishers, Munich, 1985, and Gibson, L. J .; Ashby, M. F. "Cellular Solids. Structure and Properties" Pergamon Press, Oxford, 1988. The term "insulator" refers to a material that reduces the transfer of energy from one location to another. The term "absorbent" refers to materials that absorb and retain or distribute fluids, usually liquids, often water as an example that is a sponge. The term "filter" refers to materials that pass a fluid either gas or liquid, while retaining impurities within the material. The term "carrier" refers to materials that retain a second substance, usually a liquid, until a time when the second substance is necessary to a separate purpose at which point it is removed by pressure.

Many of these applications require foam to resist combustion. Many building codes, for example, include restrictions on the flammable capacity of materials including foam insulation. Similar restrictions may apply to insulators used in clothing or protective devices. However, most of the plastic materials, including foams, burn quickly. In order to provide for the safe use of such materials in those applications, various approaches to retard the flammability capacity of organic polymers have been developed. Those approaches are generally discussed by Jon Lyons in the book "The Chemistry and Uses of Fire Retardant," Robert Krieger Publishing Co., Malabar, FL, 1987. Those approaches are diverse although it generally comprises the inclusion of compounds that f have certain heteroatoms generally chlorine, bromine, phosphorus, bromide and / or antimony in the organic polymer. These compounds include small molecules, oligomers and polymers. Inorganic additives are also used, including antimony trioxide and related salts as well as salts containing borate or phosphate anions. The science flame retardancy as applied to conventional plastic materials is reasonably well developed as described in the cited text. The additional properties of foam frequently required depend on the use ^ pretended. These generally include one or more of the following: (19 low density, (2) flexibility, (3) resistance (to compression and tension), (4) ability to open, and (5) morphology control). Low density foams are more efficient since for most uses a certain volume is required. A low density foam imposes less mass to cover this objective. Flexible foams are typically generated by maintaining a relatively low vitreous transition temperature ("Tg") of the foam. Resistance is a parameter that can be challenged for achieve concurrent with a low Tg and / or lower density. The resistance (regardless of density) is generated more effectively including agents of entanglement, which link the polymer chains of the foam together in a way that confers a degree of resistance to deformation and the ability to recover from deformation, for example elasticity. The opening capacity and morphology are controlled mainly by the method of forming and curing foam. One of the benefits of high internal phase emulsion foams or HIPEs is that the foams can be adapted to have one or more of the desired properties described above. The conference of flame retardation to the HIPE foams is not direct. However, it would be desirable to have the ability to make a HIPE foam of open cell high surface area that is retardant of (flame and having one or more of the following properties: (1) lower density compatible with other requirements imposed on the foam, (2) flexibility, (3) resistance, (4) a generally open cell structure, and ( 5) the ability to be manufactured to control the size of the cells produced within the foam 15 BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a flame retardant open cell polymer foam formed by polymerization of a water-in-oil emulsion high internal phase, where the foam has a value of Index of Limited Oxygen ("LOI") of at least approximately 18%. These polymeric foams are prepared by polymerizing certain oil-in-water emulsions having a relatively high ratio of water phase to oil phase, commonly known in the art and referred to herein as high internal phase or high temperature emulsions.

"HIPEs". As used herein, the polymeric foams that result from the polymerization of such emulsions are referred to hereinafter as "HIPE foams". The foams of the present invention are prepared by polymerizing a HIPE comprising a discontinuous water phase and a phase of • continuous oil wherein the ratio of water phase to oil phase (hereinafter referred to as a "W: O" ratio) is at least 3: 1. The water phase generally contains an electrolyte and a water soluble initiator. The oil phase generally contains substantially water-insoluble monomers polymerizable by free radicals, an emulsifier and other optional ingredients such as synergists, antioxidants, fillers, dyes, fluorescent elements, Ultra Violet absorbers ("UV"), opacifying agents, etc. The monomers can be selected to confer the desired properties in the resulting polymeric foam which typically include low density, a glass transition (Tg) between about -40 ° and 90 ° C, sufficient mechanical integrity for the intended end-use and a microporous morphology. of open cell.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 of the drawings is a photomicrograph (50x magnification) of a cutting section of a representative representative polymeric foam of the present invention made with Example 1 (A) described herein. The foam has a Limited Oxygen Index ("LOI") value of 26.9% and a density of 25mg / cc and consists of 77% chloroprene of flame retardant monomer, 3% of antimony trioxide and 20% of divinyl benzene . Figure 2 of the drawings is a photomicrograph (500x magnification) of the foam of Figure 1.

Figure 3 and Figure 4 of the drawings are photomicrographs (4000x magnification) of the foam of Figure 1.

DETAILED DESCRIPTION OF THE INVENTION I. HIPE Foam Characteristics The HIPE foams of the present invention are comprised of specific combinations of monomers that to a greater degree control the final properties of the foam. The types of monomers used remain within The following general categories: (1) monomers that help maintain a desirable ßP Tg in the resulting polymer, (2) monomers which helps to confer "firmness" to the resulting polymer, referred to herein as "firmness monomers" and ( 3) monomers having a di-, tri-, tetra-, functionality and higher useful for conferring entanglements within the resulting polymer, referred to herein as interleavers. These entanglements are particularly critical to achieve the desired compressive strength or modulus and / or elasticity that is required for many foam applications. The monomers that confer resistance while They lack sufficient molecular flexibility to increase the Tg. Examples include divinyl benzene, an interlayer where higher levels can increase the resistance of the polymer while also increasing the Tg. Tg is usually important for the use of any polymer. While in some applications a relatively high Tg may be desired, many uses require a degree of flexibility that requires a lower Tg that is generally more difficult to obtain by means of the formulation than a higher Tg. Likewise, with the foams derived from In the case of a HIPE, the dehydration process can be significantly complicated in the case of a foam with very high Tg (> 100 ° C).

It will be recognized that in some cases, it is not necessary to use all the monomer types described above. In fact, in a preferred embodiment of the present invention, where the monomers conferring the flame retardancy are copolymerized to form the desired foam, it may not be necessary to use different • monomers in categories (1) and (2). In such embodiments, the monomer conferring the flame retardance can also serve the functions of maintaining the Tg and providing the requisite firmness.

II. Flame Retardation 10 The HIPE foams of the present invention are polymeric foams ^ Jj) flame retardants. One technique for measuring flame retardancy of materials is the Limited Oxygen index technique (referred to herein as "LOI"). This technique is described in detail below. While other techniques for measuring flame retardancy are known, a "flame retardant" polymer foam as referred to herein has a LOI value of at least about 18%. With respect to polymeric foams, the term "flame retardant", as used herein, refers to the foams themselves. With respect to additives, ingredients, components, agents, monomers, polymers and the like, the term "flame retardant" as used herein, refers to the ability of the additive, etc. to confer the flame retardance of the polymeric foam. Such flame retardant additives, etc. they are also referred to herein as "materials that confer flare retardation". Flame retardant additives are widely available commercially for use with many types of polymers. Generally, the materials that provide flame retardants make use of the elements bromine, chlorine, phosphorus, antimony and / or boron, and less frequently elements that include silicon, aluminum, sulfur and selenium. in a stable molecule that is incorporated into a plastic at some convenient processing stage. However, the flame retardation conference to the HIPE foams of the present invention is not direct. Unlike, for example, the ^ polystyrene foams such as Styrofoam ™, the foams of the present invention are not thermoplastic. Therefore, the flame retardant additives may not be included in a melting phase prior to the formation of the foam. Similarly, in contrast for example to blown polyurethane foams, these materials confer flame retardance and can not be simply included in an initial organic phase which is blown by gas to form the structure of the foam. 10 The inclusion of a material that confers the flame retardation in the? HIPE foam manufacture can take place either in the pre-emulsification, the post-emulsification but before the polymerization or by further treatment of the foam already formed. The inclusion in the oil phase or in the pre-emulsification of the aqueous phase is restricted by the need to maintain the stability of the emulsion during the polymerization. To have compatibility with free radical polymerization, and the desire to avoid any negative impact of the desired mechanical properties of the resulting foam. Likewise, the material that confers the flame retardance must subsist with its basic function intact through this processing. The addition to the emulsion before polymerization must be done additionally to ensure a efficient dispersion throughout the emulsion while maintaining its stability. Inclusion by application to the finished foam requires a suitable method for the addition of the required agents which ensures the proper homogeneity of the application. Many such processes as apply to HIPE foams can be impractical in scale. Most additives fire retardants are insoluble in water, they need application either as a solution in some organic solvent or by means of a separate emulsion. The three approaches, in so much that they are typically viable and are within the scope of the present invention, they may therefore be limited depending on the specific characteristics and scale of production. ^ On balance, the inclusion of the material that confers the flame retardation in the oil phase before emulsification is found to be the most practicable. However, this limits the range of flame retardant additives that can be used for some of the reasons stated in the preceding paragraph. In general, organic compounds that include polymers as well as small molecules that include the elements bromide, chlorine, boron and / or phosphorus and that are substantially insoluble in water and substantially non-reactive during radical polymerization? free, they were found to have utility in this regard. While the inclusion in the oil phase is often the most practical, any combination of the above general procedures can be used to confer the desired level of flame retardancy while the other required properties of the flame are achieved.

HIPE foam. The flame retardant treatment should not undesirably alter the thermomechanical properties of the foam in a form that can not be conveniently compensated by other means. For example, the exclusion of the alkyl acrylate group as a Tg reducing monomer (which is preferred as described below) makes the production of a low Tg foam relatively challenging. The inclusion of phosphate esters in the oil phase (or by subsequent formation application) can reduce the Tg of the foam due to plasticization. This effect is counteracted in a relatively easy manner by including more of the Tg firmness or entrainment monomers such as styrene or dikyl benzene ("DVB"). 25 The specific nature of the material conferred by flame retardancy is highly varied as described in Lyons (supra). Generally, Flame retardant additives contain some level of halogen (preferably bromide or chlorine), phosphorus (often as an alkyl phosphate ester), boron and / or antimony. Frequently, a flame retardant additive may include two or more of these elements, such as, for example, tris [1,3-dichloropropyl] phosphate, which includes halogen (Cl) and match (P). Antimony is the one most commonly used as antimony trioxide, an inorganic salt that is poorly soluble in general. It has been found that this salt works primarily as a synergist for other flame retardants, especially those that contain halogens. As long as it is not bound to theory, it is considered that this is auxiliary to react with the halogens present to from the flame retardant to produce antimony trihalide in situ. The use of? Synergists such as the antimony compounds are described in detail below. Although the mechanism of retardation is not understood in all aspects, it is considered that the retardant is responsible for generating radicals in the phase of steam before the polymer is heated. These radicals can then be combined with more reactive radicals present and generated by the flame itself. This can serve to extinguish the most reactive components in the incandescent vapor phase, reducing the temperature and therefore eliminating incandescence. The flame retardant organic polymers are not necessarily more stable when They heat and often carbonise (a feature that can inhibit combustion advantageously) and / or release excess smoke. However, these processes typically do not contribute to the propagation or dispersion of a flame caused by heat, spark, fire, radiant energy, etc. As described above, it is preferred that the polymer that is retardant have a relatively high level of stability when warms to not depolymerize and produce a volatile flammable gas (depolymerized monomer) in the air on the polymer. The depolymerization is associated often with the maximum temperature of a polymer (or copolymer) Tc. Generally the polymers have branching in the main chain (for example polymethyl methacrylate or poly (α-methyl styrene) have comparatively low upper temperatures.This generally leads to the polymers being made with those monomers.

It has generally been found that copolymers having low maximum temperatures are more difficult to retard with respect to flammable capacity. Therefore, such monomers are preferably avoided. While alkyl acrylates such as 2-ethylhexyl acrylate ("EHA") are not known to have particularly low Tc values, it has been found that in the development of this invention they complicate efforts to reduce the flammable capacity of HIPE foams. described in the present. For example, HIPE foams containing acrylate acrylate will generally require higher levels of flame retardant additive of any type to achieve the desired level of retardation. The replacement of this type of monomer with other types that not only serve a reduction function of Tg but also reduce the flammable capacity 15 can be beneficial. The following describes the different ways in which the flame retardant ingredients can be conferred to the HIPE foams without interfering with I key aspects of the process (for example, curing, emulsification, property development, etc.). 20 A. Ways of Conferring Flame Retardation i) Copolymerizable Monomers In the most preferred method of inclusion of the material conferring the flame retardance is a copolymerizable monomer included in the oil phase of the flame. the HIPE. This comprises a monomer reactive with the other comonomers in free radical polymerization wherein the monomer contains at least one of the following elements: Cl, Br, P, B or Sb. The requirement for polymerization requires the presence of at least one reactive double bond as is well known to those skilled in the art. The copolymerization of the flame retardant additives prevents premature volatilization of the flame retardant as the polymeric foam is heated during the current ignition conditions. If the flame retardant is deactivated by heat from a nearby fire before ignition, obviously little or no flame retardant activity will remain when the ignition temperature is reached. Also, in some applications, for example involving the exposure of organic solvents, a flame retardant that does not covalently bind can be extracted from the foam, against the elimination of its activity. Furthermore, in some applications, the foam can be exposed to ambient heat conditions, for example, the interior of a car, which can lead to the volatilization of the flame retardant. An example of the polymerizable material that confers the flame retardancy used to make the blown polyurethane foams is provided in WO 97/44368 (Willkomm and Hinze) filed May 23, 1996. These flame retardant additives, however, are not suitable for HIPE foams since they only function for condensation polymerizations as is typical of polyurethane formation. Non-limiting examples of flame retardant monomers that are substantially insoluble in water, do not interfere with free radical polymerization, and that are incorporated by polymerization of free radical in the network of HIPE foam include 2-chloro-1,3-butadiene (hereinafter "chloroprene"), 2,3-dichloro -1, 3-butadiene (hereinafter referred to as "dichloroprene"), isomers of chlorostyrene, dichlorostyrene and tricolorostyrene, octachlorostyrene, pentabromophenyl acrylate and methacrylate, isomers of bromostyrene, dibromostyrene and tribromostyrene, 1,3-dibromopropyl acrylate, 2,4,6 -tribromophenyl acrylate, 2-bromo-1,3-butadiene (hereinafter "bromoprene"), 2,3-dibromo- 1,3-butadiene (hereafter "dibromoprene"), 3-6-dichloro-1,3,7-octatriene, vinyl dipropyl phosphate, vinyl diphenyl phosphate, tris [styryl] phosphate, vinyl chloride, vinylidene chloride, bromide of vinyl, vinylidene bromide, divinyl phenyl phosphate, 2,3-dibromobutan-1,4-diol ^ diacrylate, chlorodivinyl benzene, brominated alkyl acrylates and general chlorinates, diacrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, methacrinitriles, other halogenated styrenics and related compounds having the requisite double reactive bond and the flame retardant elements. The inclusion of such polymerizable materials that confer retardation flame retardant or flame retardant monomers as described above in levels on a »Small percentage (which is required in general for sufficient efficiency) can have a significant effect on the thermomechanical properties of the polymer. For example, the addition of a monomer such as 4-chlorostyrene requires the reduction of the levels of the other monomers in the formulation which are intended to maintain a Tg desirably low, for example 2-ethylhexylacrylate (EHA). The result can be a foam that has a good flame retardancy although thermomechanical properties out of what is desired for the final use and / or processing. In this case, the inclusion of the flame retardant monomers which also serve to reduce the Tg of the resulting foam may be highly desirable. Examples of such types include chloroprene, Bromoprene, dichloroprene, dibromoprene and brominated alkyl acrylates having relatively long alkyl chains, typically having at least 4 carbon atoms in the chain attached to the ester moiety. Particularly preferred examples include chloroprene and dichloroprene. i) Non-Covalently Combined Polymers 25 Another preferred method is to include polymers non-covalently combined in the emulsion. These polymers are included in the oil phase before the emulsification and are a separate polymer containing one or more of the elements Cl, Br, P, B, or Sb. Such polymers are basically inert during the polymerization step and do not covalently bind in the formation of the polymer network . Due to the generally poor solubility of one polymer dispersed within another, those polymers will often make separate phase and form regions within the other polymer of the relatively pure combined polymer. Since the polymers are generally non-volatile, this approach also prevents premature volatilization of the flame retardant additive as the polymer system is heated. However, this approach may be less efficient since the unreacted polymer does not typically increase the mechanical properties of the resulting foam as well as a reactive monomer covalently incorporated within the polymer network. Also, a solution of a polymer within the oil phase can increase the viscosity of that oil phase undesirably and make it non-emulsifiable. For this reason, insoluble entangled polymers that are suspended in the oil phase may be preferred. Particular non-limiting examples of such polymers include polyvinyl chloride, polyvinylidene chloride, brominated polystyrene, polyvinyl bromide, polyvinylidene bromide, polyvinyl diphenyl phosphate, the polymer of a quaternary ammonium salt such as diethyl polyethylene imine having a counter ion such as hexachloroantimonate or phosphate or borate and the like. Other examples are cited in U.S. Patent No. 4,164,522 (Gibbs) issued August 18, 1979 and Patent North American No. 4,186,156 (Gibbs) issued January 29, 1980, which are incorporated herein by reference. iii) Non-polymeric flame retardant additive Non-polymer materials that confer flame retardancy comprise the largest commercially available class of flame retardant additives. general. Typical examples are described in brochures available from companies such as Albright & Wilson of Richmond, VA, Dover Chemical of Dover, OH, Albemarle Chemical of Baton Rouge, LA, Laurel Chemical of Cleveland, OH and Akzo Novel of Dobbs g ^ Ferry, NY. Commercially available types include a wide range of brominated and chlorinated aliphatic compounds such as ChloroWax ™, decabromodiphenyl oxide, tetradecabromodiphenoxy benzene, tetrabromocyclooctane, dibromoethyldibromocyclohexane, ethylene bis (tetrabromophthalimide), dibromoneopentyl glycol, brominated polystyrene, and hexabromocyclododecane, phosphate and phosphate esters such as tris [1,3-dichloropropyl] ] phosphate and bis (2-chloroethyl) 2-chloroethyl phosphonate and borate esters. These materials that confer flame retardance can be combined? with the foam of the present invention by any process found to be convenient. These may include in the water oil phase as non-reactive co-ingredients, applied to the formed emulsion, applied after polymerization, for example, during any washing process by spraying on the foam, 15 bath inside the foam , spray on the foam or deposition in the foam of a condensation vapor. The combination of any of the methods of addition may be useful. iv) Inorganic Salts This class comprises substantially inorganic ionic species which contain one or more of the Cl, Br, P, B, or Sb elements. Such elements can be used as electrolytes in the aqueous phase prior to emulsification. Other means for using such materials is to apply them to the foam by a variety of methods including spraying, infusion, by means of bath after drying, exchange ionic with other salts present in the foam, vapor phase deposition, acid neutralization, etc. non-limiting examples include antimony tartrate, antimony caproate, antimony thioxide, antimony phosphate, salts containing antimony hexahalide, antimony trisulfide, antimony borate, ammonium phosphate (including polyphosphates such as pyrosphosphate and tripolyphosphate and hexametaphosphate), ammonium borate, calcium phosphate, calcium chloride , calcium bromide, calcium borate, calcium tetrachlorophthalate, sodium ethyl phosphinate, sodium borate and other combinations of these or anions related to suitable cations of any kind (for example, one can generally substitute magnesium for calcium in the examples previously cited). A preferred means of application of any of the examples involves the ion exchange of calcium chloride (which is a preferred electrolyte present within the aqueous phase of the emulsion and residual to the polymerized foam) with a soluble sodium salt having the desired counterion which is insoluble afterwards with the counterion of calcium exchanged. For example, one can wash the foam containing residual calcium chloride with water-soluble sodium borate or sodium phosphate which produces an insoluble calcium salt which is substantive to the foam during aqueous washing. v. Chemical Modification of HIPE Foam This process involves the chemical modification of a HIPE foam to confer a flame retardance. This process is general for all HIPE foams although it is more practicable for HIPE foams made using dienes that undergo 1, 4-polymerization, thus leaving residual double bonds in the foam after polymerization. Exemplary dienes include butadiene, isoprene, piperylene, chloroprene, dichloroprene, 1,3,7-octatriene, bromoprene, dibromoprene, and related compounds such as those described in US Patent No. 5,767,168 (Dyer et al.) Issued June 16. 1998, incorporated herein by reference. These foams can be exposed to halogens such as bromide to brominate of double bonds. Exposure to halogens in water typically forms halohydrin. Exposure to dichlorocardene and / or dibromocardene results in the formation of a dichloro or cyclopropyl dibromo derivative by addition through the double bond. This can be conveniently effected through the combination of a mixture of chloroform, sodium hydroxide, tetra-n-butyl ammonium chloride (or other Phase Transfer Catalyst - PTC), and water that provides dichlorocarbene which is added to through the double bond to increase the chlorine content of the foam (see similar example in Ramesan, MT; Alex, RJ Appl, Polym, Sci. 1998, 68, 153-160, incorporated herein by reference and Dyer, J. Or Ph.D.Dissertation, The University of North Carolina at Chapel Hill, 1980). Generally, any technique known to those of skill in the art that can modify the foam to increase the content of Cl, Br. B, P, or Sb may be useful. In the examples where halogens such as Br and / or Cl are added to the formed foam, it will generally also be desirable to have antimony trioxide present either by application after the foam is worked up or by inclusion in a precursor stage. Emulsification by adding the emulsion formed with mixing followed by curing.

B. Synergistic It has been found that certain agents enhance the efficiency of certain flame retardant agents present in a polymer. Such materials, called synergistic, are often preferred ingredients in the HIPE foams of the present invention. The most preferred example of a synergist is antimony thioxide (empirically denoted as Sb2O6 in most texts). It has been found preferable to include the antimony trioxide as an insoluble component suspended in the oil phase prior to emulsification. The antimony trioxide used is one degree of very fine ground to aid in the suspension of the particles, such as that available from Laurel Chemicals of Cleveland, OH. These synergists are included in the oil phase typically at levels of between about 0.5% and about 10% by weight of the phase of , more typically between about 1% and about 5%, more typically at a level of about 3%, when used with other flame retardant materials of the types generally described supra. It is important to note that those levels described for the synergists with in addition to the level of flame retardant component included in the polymeric foam. The synergistic, applied to the foam, significantly reduces the amount of flame retardant additive • necessary to confer a predetermined retardation level.

O Index of Limited Oxygen (LOI) A critical parameter of the foams of the present invention is the LOI.

This technique for measuring the flammable capacity of materials is generally described in Horrocks, A. R .; Tune, M .; Price, D. "" he Burning Behavior of Textiles and its Assessment by Oxygen-lndex Methods ", Textile Progress, Vol 18 Number 1/2/3, The Textile Institute, Manchester, UK, 1989, and in" The Chemistry and Uses of Fire Retardants ", cited above Typically, in this test, a sample of material is suspended vertically and ignited in an atmosphere enriched with oxygen, for example, up to about 30% partial pressure. The level of oxygen in the system is gradually reduced and the point at which the extinction occurs is recorded. (The end point can be defined in a variable way through several experiments). For purposes of the present invention, the method described in ASTM D-2863 is that used).

A high LOI value suggests that the material would burn poorly under working conditions. LOI does not refer to the flammable capacity of a material as a result of the application of heat, light, sparks, electric current, combustion cigarette ashes, and the like, nor determines the toxicity or amount of gases produced during heating or ignition. However, it is a quantitative laboratory measure of the ^^ Flammable capacity that has become widely used as an indication primary flame retardancy. For the purposes of the present invention, a HIPE foam is considered to be flame retardant if the LOI value is at least about 18%, preferably at least 21%, more preferably at least 23% and more preferably of at least about 25%.

Typically foams will have a LOI value from about 18% up to 9 about 35% and more commonly from about 21% to about 30%. Generally, a material that has an LOI greater than about 21% will extinguish without assistance after the removal of the flame source. The sample may continue to burn if it is kept in a very hot as it would be in a fire. The material can also burn or smoke without flame for some time without incandescence. Therefore, a higher LOI value is often required for building materials, clothing, bedding, furniture, for example for security. In some cases, achieve a LOI value > Desirably high will cause conflict with obtaining other foam properties important (infra) in which case a lower LOI may be preferred to provide the best overall performance.

III. Other Characteristics of the Foam The polymeric foams of the present invention are of cell relatively open. This means that the individual cells of the foam are completely unobstructed communication with the adjacent cells. The cells in such substantially open cell structures have intracellular openings or "windows" that connect one cell to another within the foam structure. These substantially open cell foam structures will generally have a cross-linked character with the individual cells that are defined by a plurality of mutually connected three-dimensional branched frames. The filaments of the polymeric material that make up those branched webs may be referred to as "columns" "as used herein, a foam material is an" open cell "if at least 80% of the cells in the foam structure are of at least 1 μm in size and are in open communication with so At least one adjacent cell. This can be determined by inspecting an SEM ) of the foam. Polymeric foams can generally be hydrophobic to inhibit the passage of aqueous fluids through the foam, or hydrophilic to promote the absorption of aqueous fluids within the foam. The properties hydrophobic / hydrophilic of the inner surface of the foam structures are controlled by post-polymerization foam treatment processes. As used herein, the term "hydrophilic" is used to refer to surfaces that are wettable by aqueous fluids deposited therein. Hydrophilicity and wettability are typically defined in terms of the contact angle and the surface tension of the fluids and the surfaces of solids involved. This is described in detail in the American Chemical Society publication entitled Contact Angle, Wettability and Adhesion, edited by Robert F. Gould (Copyright 1964), which is incorporated herein by reference. It is said that a surface is wetted by a fluid (for example hydrophilic) when the contact angle between the angle and the surface is less than 90 °, or when the fluid tends to spontaneously distribute through the surface, both conditions normally coexisting. Conversely, a surface is considered to be "hydrophobic" if the contact angle is greater than 90 ° and the fluid is not spontaneously dispersed across the surface. ^ The HIPE foams of the present invention are easily optimized to confer the desired properties in each specific application. As examples, such foams may be microcellular (<10 μm) through up to moderate cell diameters (ca. 150 μm); low density (0.10 g / cc) to very low density (0.004 g / cc); rigid to flexible (corresponding, elevated Tg at low Tg (subambiental)); and from strong to weak. The foams can be provided as continuous sheets, thick boards rigid, particles of various sizes, specific shapes, etc. as required for your > end use. However, the optimized foams exhibit an important level of flame retardancy not achieved in HIPE foams in the art. These foams also do not require chlororuorocarbon ("CFC") or volatile organic compound ("VOC") during manufacturing, are generally photostable and easily produced in large quantities with reasonable savings of either earthenware material, rolling stock, particle foam and the like.

A. Vitreous Transition Temperature Typically, an important parameter of the foams of the present The invention is the glass transition temperature (Tg). The Tg represents the most average point of the transition between the vitreous and elastic states of the polymer. Foams that have a Tg greater than the temperature of use can be very strong although they can also be very rigid and potentially prone to fracture. Such foams also typically take a long time to recover to expanded state after of having been stored in the compressed state during prolonged periods.

Although the end use of a particular foam is an important factor when determining the desired Tg of the foam, preferred are foams having a Tg from about -40 ° to about 90 ° C, more preferably from about 0 ° to about 70 ° C. ° C, more preferably from about 10 ° to about 50 ° C. The method for determining Tg by the Dynamic Mechanical Analysis (DMA) is described in the TEST METHODS section of U.S. Patent No. 5,753,359 (Dyer et al.), Issued May 19, 1998, incorporated by reference herein.

B. Foam Density Another potentially important property of the foams of the present invention is their density. The "foam density" (ie, in grams of foam per cubic centimeter of the volume of foam in air) is specified herein on a dry basis, unless otherwise indicated. Any suitable gravimetric method that will provide a determination of the mass of the solid foam material per unit volume of the foam structure can be used to measure the foam density. For example, an ASTM gravimetric process described in greater detail in the TEST METHODS section of U.S. Patent No. 5,387,207 (Dyer et al.), Issued February 7, 1995 (incorporated herein by reference) is a method which can be used for density determination. While the foams can be made virtually with any need varying from below that of the air to just less than that of the volume density of the polymer from which it was made, the foams of the present invention are most useful when they have a dry density in the expanded state of less than about 250 mg / cc, generally between about 80 and about 12 mg / cc, and more generally between about 50 and 20 mg / cc.

The exact preference depends on the nature of the application under consideration and could vary within those ranges.

^ O Cell Size 5 Foam cells and especially cells which are formed by polymerizing an oil phase containing monomer surrounding relatively monomer-free water phase droplets, will often be substantially spherical in shape. The size or "diameter" of such spherical cells is a parameter commonly used to characterize foams in general. Since the cells in a given sample of polymer foam will not necessarily be from? the same size, a cell of average size, that is, the average cell diameter, will often be specified. A number of techniques will be available to determine the average cell size of the foams. However, the most useful technique for determining cell size in foams involves a simple measurement based on the scanning of the electronic photomicrograph of a foam sample (See Figure 1). The cell size measurements given herein are based on the average numeric cell size of the foam, for example as shown in Figure 1. The foams of the present invention will generally have a size of 20 average numerical cell of no more than about 150 μm, more generally from about 10 to 100 μm, and more generally from about 15 μm to 35 μm. With the other foam characteristics, the average cell size for a given foam will be defined in part by its anticipated end use. For example, in the applications associated with thermal insulation, the relatively smaller cells are the ones desired to reduce the importance of the radiant transmission of the thermal energy within the system. In applications associated with filtration, the cell size will vary according to the filter requirements.

D. Elastic Limit The elastic limit is determined in an experiment of stresses and strains conducted on the foam at a specified temperature and speed of formation (in the compression mode). The elastic limit is the stress in the transition from the linear elastic region to the plate region of the stress and strain curve. The yield strength is indicative of the general strength properties of the polymer foam at a temperature of interest. For many applications, higher values of the yield strength are desirable at a given foam density and Tg. The foams of the present invention will preferably have an elastic limit value of at least about 0.25 psi. preferably at least 0.50 psi.

IV. Uses of Foam The polymeric foams of the present invention have numerous end uses. For example, foams can be prepared as absorbent materials, particularly for aqueous fluids such as urine and menstrual discharges. Such foams will be prepared to have structural characteristics similar to the HIPE foams described for example in U.S. Patent No. 5,650,222 (DesMarais et al.) Issued July 22, 1997; U.S. Patent Application No. 08 / 542,497 (Dyer et al., issued October 13, 1995); U.S. Patent No. 5,387,207 (Dyer et al.), issued February 7, 1995; U.S. Patent No. 5,550,167 (DesMaris) issued August 27, 1996; and the North American Patent No. 5,563,179 (DesMarais et al.), Issued October 8, 1996, each of which it is incorporated by reference to the present. Such absorbent foams can be included in absorbent particles such as infant diapers, feminine hygiene articles (e.g. tampons, menstrual pads), adult incontinence articles and the like, such as those described in the aforementioned co-pending patent applications and issued patent. . The flame retardant aspect of the foams of the present invention allows their use in wider areas than if this feature did not appear. For example, these foams can be used in furniture and beds (mattresses, internal springs, pillows) as part of the elastic portion of each one of them. The foams can be used in seat cushions in cars, trains, airplanes, boats, etc. The foams can also be prepared to be useful as insulators. Such foams will have structural characteristics (for exampleCu. , cell size, density, Tg), similar to the foams described in U.S. Patent No. 5,633,291 (Dyer et al.) issued May 27, 1997 and U.S. Patent No. 5,770,634 (Dyer et al.) issued June 23, 1998, both incorporated herein by reference. Flame retardation is required to cover certain building codes for insulating materials as well as furniture and clothing. Foams (treated to be hydrophilic) can also be used as absorbent curtains in surgical wards where flame retardation is important. The foams can be used as a filter or component of a composite filter for air or oils where flame retardation can be an advantage. Other general uses of the flame retardant HIPE foams include the use of loudspeaker enclosures to dampen undesirable acoustic frequencies, in underwater helmets to absorb acoustic energy, in bed mattresses, mattress covers, pillows, sheets and the like, in the protective apparatus such as that which is used by firemen as a thermal insulator, in gloves to protect against heat, and cold, in insulating containers such like coolers, in cars, trains and airplanes as acoustic and thermal insulators and in cushions such as conveyors, in food protection bags, in shipping containers to protect sensitive items against mechanical impact, in gas and fuel tanks and pipes , as filters for air and especially mable liquids in roofing tiles, carriers for ink, dyes, lubricants, lotions and for making light items.

V. Preparation of e retardant Polymeric Foams A. General The polymeric foams of the present invention are prepared by polymerization of HIPEs. The relative amounts of water and oil phases used to form the HIPEs determine the density of the resulting foam. Density is, among many other parameters, critical to the mechanical and performance properties of resulting polymeric foams. The water to oil ratio in the emulsion can also influence the size and dimensions of the cell in the columns that form the foam. The emulsions used to prepare the HIPE foams will generally have a volume to weight ratio of water to oil phase of at least about 3: 1, preferably at least about 12: 1. Typically the volume to weight ratio will be from about 12: 1 to about 85: 1 most commonly from about 20: 1 to about 50: 1. The process for obtaining these polymeric foams, which will have a LOI value of at least about 21%, comprises the steps of: (A) forming a water-in-oil emulsion from: (1) an oil phase comprising: (a) from about 80% to about 98%, by weight of the oil phase, of a monomer component comprising: (i) from about 0% to about 90% by weight of the monomer component, of a monofunctional monomer substantially insoluble in water capable of forming a homopolymer having a Tg of about 40 ° C or less; (ii) from about 0% to about 70% by weight of the monomer component, by weight of a monofunctional monomer substantially insoluble in water capable of imparting firmness approximately equivalent to that provided by styrene; f (iii) from about 5% to about 50% by weight of the monomer component, of a first polyfunctional entanglement agent substantially insoluble in water selected from the group consisting of divinyl benzene and analogs thereof; and (iv) from about 0% to about 20% by weight of the monomer component, of a second polyfunctional entanglement agent substantially insoluble in water selected from the group consisting of diacrylate and dimethacrylates of diols and analogs thereof; and (b) from about 2% to about 20% by weight of the oil phase, of an emulsifying component that is soluble in the oil phase and that is suitable to form a stable water-in-oil emulsion; (2) an aqueous phase comprising from about 0.1% to about 20% by weight of the aqueous phase of a water-soluble electrolyte; 25 (3) a volume to weight ratio of aqueous phase of the oil phase of at least about 3: 1; Y (4) wherein the emulsion comprises one or more components that impart e retardance to the polymeric foam, wherein one or more components are included in the level of at least about 5% of the total weight of the oil phase; and (B) polymerizing the monomer component in the oil phase in the water-in-oil emulsion to form the polymeric foam. The term "monofunctional", as used herein, refers to a polymerizable portion. The term "polyfunctional", as used herein, refers to more than one polymerizable portion. The polymeric foam material can be subsequently washed and dewatered iteratively to provide a dry hydrophobic foam. Alternatively, the foam can be converted to hydrophilic by an appropriate surface treatment with any of a number of hydrophilizing agents, including calcium chloride and similar salts, residual emulsifiers used to establish the HIPE, and other wetting agents well known to those with experience in the technique. Hydrophilization treatments are described in, for example, U.S. Patent No. 5,387,207 (Dyer et al), issued February 7, 1995 (see especially column 22 to column 24), which are incorporated herein by reference. Since the presence of certain salts can themselves confer a degree of flame retardation, it may be desirable to leave them present in the foam. A non-limiting list of examples includes ammonium phosphate, calcium phosphate, calcium hexachloroantimonate, calcium hexabromoantimonate, calcium tetrafluoroborate, calcium chloride, calcium ammonium phosphate, calcium borate and the other analogs of group IA and NA Group of those salts. The residual calcium chloride is often associated with hydrophilicity and corrosion of the material that may not be preferred in all cases. However, the water retained from hydration of this salt contributes to the Flame retardation. In practice, these salts can be applied in any washing step designed to remove the salt used in the emulsion. Such a washing step may comprise a simple ion exchange to convert the soluble calcium chloride used in the emulsification to another calcium salt by treatment with the soluble sodium salt as part of the aqueous wash solution. If this step is followed by thermal drying (infra), the applied salt can migrate with the aqueous washing fluid evaporating from the surface of the foam and concentrate there beneficially with respect to the surface flame retardance. While those steps are better with respect to flame retardation, they have not been found to be sufficient by themselves to confer the desired and high LOI values characteristic of the foams of the present invention. These foams can be formed as desired. Typically, this training will comprise sheet trimming. These sheets can optionally be compressed, for example continuously through pressure contact points within a thin state and wrapped in rolls. The compressible sheets can retain their relatively compressed thin state under unwinding, applied as desired and heated above their activation temperature (usually around the Tg of the polymer) or allowed to sit for a relatively long period, for example several weeks or months depending on the ambient temperature as described in U.S. Patent No. 5,770,634 (Dyer et al.) issued June 23, 1998, incorporated herein by reference. Alternatively, the shapes may be conferred by the shape of the container in which HIPE is cured to form the polymeric foam material. Such foams are defined as "compressible" when the foam is compressed to 33% of its original expanded thickness and subsequently maintained without artificial restraint on its surface, the foam that is re-expanded by no more than 50% after 21 days at 22 ° C. The method to measure the ability to understand is described in U.S. Patent No. 5,770,634 incorporated herein by reference. Alternatively, the cured foam can be cut, cut, subjected to shear, crushed or otherwise pulverized into small pieces of particle for later use. 1. Oil Phase Components The continuous oil phase of the HIPE comprises comonomers that are polymerized to form the solid foam structure. This monomer component is preferably formulated to be capable of forming a copolymer having a Tg from about -40 ° C to about 90 ° C, and generally from about 0 ° to about 70 ° C, more generally from about 10 ° to about 50 °. This monomer component preferably includes at least one component that imparts flame retardance to the foam structure. Such components are described in detail under the headings Copolymerizable Monomers, Polymers Combined non-covalently, unpolymerized flame retardant additives and inorganic salts. Such components are presented collectively at a level of at least about 5% (for example two components must each be present at levels of 3%, each collectively giving 6% by weight of the oil phase). Various flame retardant ingredients can be equally effective at a given level, the level used will depend on the specific material conferred by the flame retardance employed, although it will generally be from about 8% to about 9% and more generally from about 25% to about 80. %. The levels of such lower components of about 5% are found to be minimally effective. Also, components at levels such as approximately 20% can alter the thermomechanical properties of the polymers in a significant way. This may require the formulation of other monomers to compensate. For this reason, as well as in the consideration of the expense of some flame retardant additives, it is desired to manage the level of retardation that confers the material to be so low that it will confer the degree of retardation necessary for the specific application. The monomer component of the oil phase can typically comprise lower monofunctional monomers Tg, monomers imparting firmness, at least one polyfunctional crosslinking agent, to at least one emulsifier. It is important to note that any or all of the monomer components can be selected or modified to contain one or more elements that confer retardation to the resulting foam. In addition, the oil phase can contain optional and additional components. Optional oil phase components include synergistic elements (described above), antioxidants, plasticizers, filler particles, dyes (dyes or pigments), fluorescent agents, chelants, opacifying agents, and chain transfer agents.

The monomer components are described in detail below. The selection of the particular types and amounts of monofunctional monomer or monomer and the comonomer (s) and the polyfunctional crosslinking agent may be important for the performance of HIPE foams having the desired combination of structure and mechanical properties that converts such materials into suitable for use in the invention herein. It should be understood that when the material conferring the flame retardance also serves as a reducing monomer Tg, a strength monomer, an entanglement monomer and / or an emulsifier, its level will exceed 5% by weight of the oil phase as It was established before and so that the flame retardant additive is not necessary to complete with the scales established on the component. For example, a HIPE foam comprising, for example 10% chloroprene and 90% DVB would exceed the 5% increase for a flame retardant ingredient containing one or more of the following elements (Cl, Br, P, B, Sb) and it would not be necessary to adjust to meet the ranges described. • to. Monofunctional Tg Drop Monomers A component of the oil phase comprises at least one monofunctional comonomer whose amorphous tactical homopolymer has a Tg of about 40 ° C or less (see Brandup, J .; Immergut, E.H. "Polymer Handbook", 2nd Ed., Wiley-lnterscience, New York, NY, 1975, 111-139), hereinafter described as a "Tg reducing monomer". These monomers have to impart properties similar to the resulting polymer restructuring. It is preferred that alkyl methacrylate, alkyl acrylate, alkyl methacrylamide, alkyl acrylamide and monomers of this general type are avoided. These monomers produce foams that are more difficult to converting into pyro-retardants, for example, require higher levels of flame retardant ingredients than foams where those monomers are absent (or present at very low levels). Without wishing to be bound by theory, it is considered that these monomers are easily displaced from the polymer chain by depolymerization when the polymer is heated in air. This facet may not reduce the LOI values of the foam in intrinsic form. In that test, the foam is ignited with open flame and not gradually heated. However, in other situations, the foam may be heated prior to combustion, resulting in depolymerization. This can enrich the atmosphere over the foam with a flammable monomer that contributes to the flammable capacity. Since the prior art has a great dependence on the acrylacrylates for this Tg reduction function, this preferred restriction imposes a significant restriction on the ability to produce foams with low Tg that have Flame retardation. As discussed above, LOI is an indication of the flame retardant properties of a material and it is desirable to reduce the flammable capacity of HIPE foams below the environments that could result in a fire. Applicants have found that certain butadienes substituted with halogen are • 5 particularly effective in conferring flame retardancy and reducing characteristics of Tg. Non-limiting examples include 2-chloro-1,3-butadiene (chloroprene) and 2,3-dichloro-1,3-butadiene (dichloroprene) and the bromide analogs (bromoprene and dibromoprene), 2-chloropiperylene and combinations of such monomers Other candidates include vinyl chloride, vinyl bromide, divilidene chloride, although those monomers are comparatively toxic and volatile which imposes restrictions on? process. Of these monomers, chloroprene, dichloroprene, bromoprene, dibromoprene are most preferred. In such cases, these monomers serve as a Tg reduction component and flame retardant component, so that no other material conferring flame retardancy may be required. Since such monomers serve for a dual purpose, it has been found that this is particularly an efficient approach to achieve the desired result. Other Tg reducing monomers suitable for use herein are disclosed in U.S. Patent No. 5,770,634 issued June 23, 1998, especially including C4-C? 2 alkylstyrenes such as p-n-octylstyrene, isoprene, butadiene, 1, 3,7-octatriene and piperylene. These monofunctional monomers generally comprise from 0 to about 70%, more preferably from about 20 to about 60% by weight of the monomer component. b. Components of Imparten Firmeza The monomer component used in the oil phase of HIPEs may also comprise one or more monofunctional comonomers capable of imparting strength approximately equivalent to that provided by the styrene to the resulting polymeric foam structure. The firmer foam exhibits the ability to deform substantially without failure. Those types of monofunctional comonomer may include styrene-based comonomers (for example styrene and ethyl styrene) or other types of monomers such as methyl methacrylate when the related homopolymer is well known as an example of firmness. The preferred monofunctional comonomers of this type are styrene-based monomers that include styrene and ethylestryrene. The comonomer of "Monofunctional" strength will typically comprise from about 0 to about 70%, preferably from about 20% to about 50%, more preferably from about 30% to about 50% by weight of the monomer component. In certain cases, the "firmness" comonomer may also impart the desired rubber-like properties of the resulting polymer. For such comonomers, the amount can be included in the monomer component which will be that of the typical monomer and the comonomer combined. An example is 4-octylstyrene. Similarly, in such cases, the "firmness" comonomer may also impart the desired flame retardation to the resulting polymer. Particularly preferred examples include isomers of chlorinated and / or brominated styrene, for example 4-chlorostyrene. When those monomers are employed, no other flame retardant additive may be required to satisfy the conditions of the present invention. c. Polyfunctional Interlacing Agent The monomer component contains at least one polyfunctional crosslinking agent. As with monofunctional monomers and comonomers, the selection of the type and amount of entanglement agents is important for the realization of polymeric foams having the desired combination of structural and mechanical properties. The polyfunctional crosslinking agent can be selected from a wide variety of monomers containing one or more activated vinyl groups, such as divinyl benzene and analogs thereof. The divinylbenzene analogs useful herein include, but are not limited to, trivinylbenzenes, divinyl toluenes, divinylxylenes, divinylnaphthalenes, divinyl alkylbenzenes, divinylphenanthrenes, divinylbiphenyls, divinyldiphenyl methanes, divinylbenzyl, divinylphenyl esters, diphenyldiphenylsulfides, divinylfurans, divinyl sulfide, divinyl sulfone, and mixtures thereof. Divinylbenzene is typically available as a mixture with ethyl styrene in proportions of about 55:45. These proportions can be modified to enrich the oil phase with one or another component. Generally, it is advantageous to enrich the mixture with the ethyl styrene component while simultaneously reducing the amount of styrene in the monomer mixture. The entanglement agent can generally be included in the oil phase of the HIPE in an amount of from about 2 to about 50%, preferably from about 10% to about 35%, more preferably from about 15% to about 25% by weight of the monomer component (on a 100% base). The entanglement agent may also be selected from polyfunctional acrylates or methacrylates such as those described in U.S. Patent No. 5,770,634 issued June 23, 1998 and incorporated herein by reference. The inclusion of these typically confers the flame retardancy to the resulting foam more challengingly or requires higher levels of materials that confer flame retardancy to be effective. This second entanglement agent can generally be included in the oil phase of the HIPE in an amount from 0 to about 15% by weight of the monomer component. In certain cases, the entanglement agent can impart the desired flame retardation to the resulting polymer. Particularly preferred examples include chlorinated and / or brominated DVB such as 4-chloro-2,5-divinylbenzene and di- and tri- and tetrahalogenated acrylates such as 2,3-dibromobutan-1,4-diol. d. Emulsifiers Another essential component of the HIPE oil phase is an emulsifying component. Suitable emulsifiers are well known to those skilled in the art. Particularly preferred emulsifiers include, Span 20 ™, Span 40 ™, Span 60 ™, and Span 80 ™. These are nominally sorbitan esters derived from lauric, myristic, stearic, and oleic acids respectively. Other preferred emulsifiers include the diglycerol esters derived from monoleate, monomyristate, monopalmitate, and monoisostearate acids. A preferred co-emulsifier is ditalodimethyl amino methyl sulfate. Other preferred emulsifiers and coemulsifiers are described in U.S. Patent No. 5,650,222 (DesMarais et al), issued July 22, 1997 incorporated herein by reference. Mixtures of these emulsifiers are also particularly useful, as are purified versions of each, especially sorbitan esters containing minimal levels of isosorbide and polyol impurities. In certain cases, the emulsifier can also impart the desired flame retardation to the resulting polymer, such as when the emulsifier contains one or more of the elements Cl, Br, P, B and / or Sb. This can be achieved, for example, by brominating the double bonds of the unsaturated emulsifiers for those containing oleate groups. An optional secondary emulsifier can be included in the component • 5 emulsifier typically in a weight ratio of primary to secondary emulsifier from about 50: 1 to about 1: 4, preferably from about 30: 1 to about 2: 1. As indicated, those skilled in the art will recognize that any suitable emulsifier can be used in the process for making the foams of the present invention. 10 The oil phase used to form the HIPEs comprises 98% by weight > of the monomer component and from about 2 to about 20% by weight of the emulsifying component. Preferably, the oil phase will comprise from about 90 to about 97% by weight of the monomer component and from about 3 to about 10% by weight of the emulsifying component. The oil phase can also contain other optional components. An optional component is an oil-soluble polymerization initiator of the general type well known to those skilled in the art, such as described in U.S. Patent No. 5,290,820 (Bass et al), issued March 1, 1994, which is incorporated by reference and WO 97/44368 (Willkomm and Hinze) filed May 23, 1996, which is incorporated herein by reference. and. Optional Components The oil phase can contain optional components. Such optional components include antioxidants that may be essential in the prevention of premature aging of foams, particularly those in base to monomers based on butadiene (supra). Applicants have determined that foams based on Tg-reducing monomers such as chloroprene tend to age (discolour and / or stiffen) when exposed to air and light. Of particular importance, such aging also seems to contribute to the flammable capacity of HIPE foams. Therefore, the stabilization of such foams with respect to exposure to oxygen and light can be critical to maintaining the desired level of flame retardance. In such cases, the inclusion of a small amount of antioxidant, particularly of the type classified as Light Hidden Amine Stabilizer (HALS) or a Hidden Phenolic Stabilizer (HPS) are preferred. Such antioxidants can be applied during any convenient step in processing many of the HALS types can be included in the oil phase without interfering with the emulsification or polymerization significantly. The HPS types should generally be added in the post-polymerization as they are destroyed by the free radical initiator in many cases. Many of the HALS examples include bis- (1, 2,2,5,5-pentamethylpiperidinyl) sebacate (Tinuvin ™ 765), Tinuvin ™ 123, Tinuvin ™ 770, Tinuvín ™ 622, Chimassorb ™ 119 and Chimassorb ™ 944FL, products from Ciba Specialty Chemical of Tarrytown, NY. Non-limiting examples of HPS include lrganox ™ -1076, Irganox ™ -129, lrganox ™ -1035, lrganox ™ -1425 WL, lrganox ™ -MD 1024, lrganox ™ -1076, Irgafos ™ -12, lrgafos ™ -168, lrgafos ™ -38 and t-butylhydroxyquinone, products of Ciba Specialty Chemical of Tarrytown, NY. Also useful for conferring light stability are UV absorbent compounds, which include the general class of 2-hydroxyvenezophenones and hydroxyphenyl benzotriazoles. These UV stabilizers are commercially available under trade names such as Tinuvin ™ 234, Tinuvin ™ P, Tinuvin ™ 328, Tinuvin ™ 327 and related compounds, products of Ciba Specialty Chemical of Tarrytown, NY. The reactive UV absorbers can also be used as part of the oil phase. An example is 4-methacryloxy-2-hydroxybenzophenone. Another optional component is a plasticizer such as dioctyl azelate, dioctyl sebacate or dioctyl adipate. In such an example, these plasticizers may also contain one or more of the elements Cl, Br, P, B and / or Sb, the material conferring the flame retardation as well as a plasticizing agent. Mentioned as a general example of this type are chlorinated alkyl esters of phosphoric acid. Even another of the optional ingredients are filler particles that can harden the polymer and / or increase its thermal insulating properties. Examples of filler particles include aluminum, titanium, carbon black (aggregates such as very fine insoluble particles), graphite, calcium carbonate, talc, flame retardant polymers, insoluble entanglements and the like. Other optional components include dyes (dyes or pigments) perfumes, chelants such as zeolites, fluorescent agents, opacifying agents, chain transfer agents and the like. Such additives are typically aggregated at approximately low levels when present (eg less than 5%) and do not need to be soluble in the oil phase but may be suspended by agitation thereof. 2. Water Phase Components The discontinuous water internal phase of the HIPEs is generally an aqueous solution containing one or more dissolved components. An essential dissolved component of the water phase is a water soluble electrolyte. The dissolved electrolyte minimizes the tendency of the monomers, comonomers and crosslinkers that are Primarily soluble in water to allow them to dissolve in the water phase. This, in turn, is considered to minimize the degree to which the polymeric material fills the cell windows at the oil / water interfaces formed by the droplets of the water phase during polymerization. Therefore, the presence of the electrolyte and the resistance ion resulting from the water phase is considered to determine to what degree the preferred polymeric foams may or may not be open cell. An electrolyte capable of imparting ionic resistance to the water phase can be used. Preferred electrolytes are inorganic mono-, di-, or trivalent salts such as water-soluble halogens, for example, chlorides, nitrates and sulphates of alkaline metals and alkaline earth metals. Examples include sodium chloride, > calcium chloride, sodium sulfate and magnesium sulfate. Calcium chloride is most preferred for use in the preparation of HIPEs. Generally the electrolyte will be used in the water phase of the HIPEs at a concentration in the range of 0.2 to about 20% by weight of the water phase. More preferably, the electrolyte comprises from about 1 to about 10% by weight of the water phase. As described above, the electrolyte in the aqueous phase can also impart the desired flame retardance to the resulting polymer when it is left as part of the final material. HIPEs will also commonly contain an effective amount of polymerization initiator. Such an initiator component is generally added to the water phase of HIPE and can be any conventional water-soluble free radical initiator. These include peroxygen compounds such as sodium, sodium, potassium and ammonium persulfates, hydrogen peroxide, sodium peracetate, sodium percarbonate and the like. The conventional reduction oxide initiator systems also can be used. Such systems are formed by the combination of previous peroxygen compounds with reducing agents such as sodyl bisulphite, L-ascorbic acid or ferrous salts. The initiator may be present in approximately 20 mole percent _ ^ based on the total moles of the polymerizable monomers present in the phase of oil. More preferably, the initiator is present in an amount from about 0.001 to about 10 mole percent based on the total moles of the polymerizable monomers in the oil phase. 3. Hydrophilizing Surfactants and Hydratable Salts The polymer that forms the HIPE foam structure will preferably be substantially free of polar functional groups. This means that the polymeric foam will be relatively hydrophobic in its characteristics. When these foams are used as insulating materials, water resistance is a generally desired characteristic. Removal of the residual emulsifier and / or saline polymerization The following may be carried out as needed by means including those described in U.S. Patent 5,633,291 (supra). Alternatively, the foam can be washed with an aqueous solution of sodium bicarbonate, which converts the residual calcium chloride to insoluble calcium bicarbonate, which greatly reduces the affinity of the water in the foam. B. Processing Conditions for Obtaining HIPE Foams The preparation of foams typically comprises the steps of: 1) forming a stable high internal phase emulsion (HIPE); 2) polymerization / curing of this stable emulsion under suitable conditions to form a foam structure solid polymer; 3) Optionally, wash the structure of solid polymeric foam to remove the residual water phase, the emulsifier and the salts from the structure of polymeric foam; 4) subsequently dehydrating this polymeric foam structure; and 5) optionally hydrophilizing the foam. As described herein, the material conferring the flame retardancy can be introduced in several stages of the manufacturing process. 1. HIPE Formation HIPE is formed by combining the oil phase and water components in the previously specified ratios. The oil phase will typically contain the requisite monomers, comonomers, crosslinkers and emulsifiers, as well as optional components such as plasticizers, antioxidants, flame retardant materials and chain transfer agents. The water phase will typically contain electrolytes and polymerization initiators. HIPE can be formed from combined phases of oil and water by subjecting these combined phases to shear agitation. The shear agitation is generally applied to the extent and for the period necessary to form a stable emulsion. Such a process can be conducted batchwise or continuously and is generally carried out under suitable conditions to form an emulsion wherein the water phase droplets are dispersed to such an extent that the resulting polymeric foam has the requisite structural characteristics. The emulsification of the combination of the oil phase and water will often involve the use of a mixing or stirring device such as a shaft propeller. A preferred method of HIPE formation involves a continuous process that combines and emulsifies the requisite oil and water phases. In such a process, a stream of liquid comprising the oil phase is formed. Concurrently, a separate liquid stream comprising the water phase is also formed. The two separate streams are combined in a suitable chamber or mixing zone of so that the specified weight ratios of the water-to-oil phase described above are achieved. In the mixing chamber or zone, the combined streams are generally subjected to shear agitation provided for example, by means of a shaft propeller of suitable configuration and dimensions. The shear stress will typically be applied to the combined oil / water phase stream at an appropriate speed. Once formed, the stable liquid HIPE can be removed from the chamber or mixing zone. The preferred method for forming HIPE by means of a continuous process is described in greater detail in US Patent No. 5,149,720 (DesMarais et al.), Issued on September 22, 1992, which is • incorporated by reference, and I, US Patent No. 5,650,222 (DesMarais et al.) (Supra). See also U.S. Patent Application No. 08 / 716,510 issued September 17, 1996 by T. DesMarais (incorporated herein by reference), which describes an improved continuous process having a cycle of recirculation for the HIPE. 2. Polymerization / Healing of HIPE The formed HIPE will generally be formed, collected or poured into a reaction vessel, container or reaction to be polymerized or cured. In a In an embodiment, the reaction vessel is constructed of polyethylene from which the polymerized / cured solid foam material can finally be easily removed for further processing after the polymerization / cure which has been carried out to the desired degree. The temperature at which the HIPE is poured into the container is generally about the same as the temperature of the polymerization / curing.

Suitable polymerization / curing conditions will vary depending on the monomer and other conformation of the oil and water phases of the emulsion (especially the emulsifying systems used) and the type and amount of polymerization initiators used. However, often suitable polymerization / curing conditions involve maintaining the HIPE at elevated temperatures above about 30 ° C, more preferably above about 35 ° C for a period ranging from 2 to about 64 hours, more preferably from about 4 to about approximately 48 hours. The HIPE can also be cured in stages such as described in U.S. Patent No. 5,189,070 (Brownscombe et al), issued February 23, 1993, which is incorporated herein by reference. An open cell HIPE foam filled with porous water is typically obtained after polymerization / cure in a reaction vessel, such as a cup or tube. This polymerized HIPE foam is typically cut or sliced into a sheet-like shape. Polymerized HIPE foam sheets are easier to process during subsequent treatment / washing and dehydration stages, as well as to prepare HIPE foam for use in insulating materials. The polymerized HIPE foam is typically cut / sliced to provide a slice cut thickness of about 2.03 cm to about 8.89 cm. 3. Treatment / Foam Washing The polymerized HIPE foam formed will generally be filled with a wastewater phase material used to prepare the HIPE. This residual water phase material (generally an aqueous electrolyte solution, residual emulsifier, and polymerization initiator) can be removed before processing and using the foam. The removal of this original water phase material will usually be carried out compressing the foam structure to squeeze the residual liquid and / or wash the foam structure with water or other aqueous washing solutions. Frequently, several compression and rinsing steps, for example 2 to 4 cycles, will be desirable. It is preferable that the water used in the washing will be heated to approximately Tg of the polymer to maintain in this way the flexibility and formability during compressive dehydration and to reduce and avoid damage to the foam structure. 4. Dehydration of the Foam After the HIPE foam has been treated / washed it must be dehydrated. Dehydration can be achieved by compression of the foam to ^ squeeze the waste water, subjecting the foam to or the water in it at temperatures from about 60 ° to about 200 ° C or a microwave treatment by vacuum dehydration or by a combination of compression and thermal / microwave dehydration techniques / of emptiness. Those foams HIPE are commonly compressively dehydrated to a thickness of about 1/3/33%) or less of their fully expanded thickness. The dehydration stage will generally be carried out until the HIPE foam is ready ^ for use and as dry as practicable. Frequently, such compression dehydrated foams will have a water content (moisture) from about 1% to about 15%, more preferably from about 5% to about 10% by weight on a dry weight basis. Alternative methods of dehydration can be used when convenient. Typically, the removal of water by evaporation is very slow to unless the water is heated. Typically, the thermal energy required to volatilize water at a reasonable speed at this level from a material is find that it is of intense energy. For this reason, the preferred top Tg of the HIPE foam of the present invention is thinned at about 90 ° C to allow compressive dehydration using hot water without destroying the structure of the foam. If you want to foam with higher Tg, another method of dehydration would need to be used.

. Hydrofilization of Foam When hydrophilic foams are desired, such as for use in absorbent articles, it may be desirable to treat the dewatered and washed foam with a hydrophilizing agent. Such suitable hydrophilizing agents and methods for hydrophilizing foams are fully described in, for example column 22 to column 24 of U.S. Patent No. 5,387,207, U.S. Patent No. ,292,777 (DesMarais) issued March 8, 1994 and US Patent No. ,352,711 (DesMarais) issued October 4, 1994, all of which are incorporated herein by reference.

SAW. Test Methods A. Flame Delay A simple laboratory method for sifting data for flammability is as follows. A sample of foam is cut to dimensions of approximately 0.5 cm x 0.5 cm x 5 cm. the sample is suspended in a holder with the larger shaft protruding forward in a ventilated laboratory hopper. The front end of the sample is lit with a propane torch. Recorded data include time for extinction and percentage of residual ash. The Limited Oxygen Index (LOI) data are executed in accordance with ASTM D-2863 on samples made 2.54 cm thick and cut into boxes of 15.24 cm x 15.24 cm. These values are reported as percentages of partial pressure of oxygen necessary to sustain the flame, including burning without significant flame.

B. Thermomechanical Property Measurements Samples are prepared for evaluation by cutting into pieces of 3 to 8mm thick and stamping those cylinder pieces that have a diameter of 2.54 cm. These cylinders or "discs" are washed successively in water (with intermediate squeezing steps) and 2-propanol to remove residual salt and emulsifier. These samples are then dried (either at ambient or at elevated temperatures up to 65 ° C). In some cases, these samples collapse when dried and must be dried by freezing to recover a fully expanded sample for the test. i. Dynamic Mechanical Analysis (DMA) DMA is used to determine the Tgs of polymers including polymeric foams. While the Tg can be determined by a variety of methods, the data reported herein is obtained using a Rheometrics RSA-II dynamic mechanical analyzer set in the compression mode using parallel plates of 25 mm in diameter. The parameters of the instrument used are cited in U.S. Patent No. 5,770,634 (infra). The glass transition temperature is taken as the maximum point of the tangent curve loss temperature (tan [d]) against the temperature. ii. Limit Elastic The elastic limit can be quantified by compressing a sample of foam at a specific speed and at a specific temperature and measuring the resistance exerted by that sample for compression. Typically, the data is formatted as a graph of stress on the y-axis, and of deformation on the x-axis. Such graphs typically show the initial linear response followed by a fast ^^ loss in additional compressive strength at a point called "point elastic. "The elastic point is defined as the intersection of the lines formed by the linear regions before and after the elastic point.The elastic tension is the voltage value at that intersection.The analysis is executed using the equipment defined in the section previous (Rheometrics RSA-II) operating in a constant voltage mode In this mode, the temperature is set at 31 ° C and the voltage speed is set at 0.1% / second.

The sample is kept at that temperature for at least 5 minutes before the Wf initiation of compression to bring it to the defined temperature. The experiment is operated for 10 minutes in compression followed by 10 minutes at the same tension rate in the reverse direction. The data analysis is conducted as described above. 15 iii. Density Density is the weight of a given sample divided by its r volume and can be determined by any appropriate standard method. The density measurements used herein involve weighing the samples from cylinder (discs) used in previous measurements that have a diameter of 2.54 cm. The thickness of the sample is determined by the measurement. The density is calculated using the equation density = weight (mg) / (0.507 x thickness (mm) expressed in units of mg / cc.) The samples are typically washed in water and 2-propanol to stir the salt and the residual emulsifier from the shows before these measurements. densities measured closely to what was expected from the relationship of Water to HIPE foam oil with the particular foam are derived, for example, density = (1 / (W: O ratio + 1)) in units of g / cc. iv. Thermogravimetric Analysis (TGA) TGA is executed on small samples using the TA system Instruments 2950 TGA equipped with an autosampler. The sweep speed is 5 ° C / minute. The temperature range is typically from the ambient to 500 ° C. The maximum on the peaks is recorded. This technique shows the weight loss of the sample as it is heated. The test is operated in air and nitrogen on identical samples in separate experiments.

Vile. EXAMPLES Comparative Example A: A HIPE foam is prepared using the following general procedure. The standard aqueous phase consists of 4% calcium chloride (anhydrous) and 0.05% potassium persulfate (initiator). The oil phase is prepared according to the monomer ratios described in Table 1. The oil phase also contains the emulsifier (s) to form the HIPE. The reference emulsifier is diglycerol monoleate (DGMO) used at a level of 4-6% by weight of the oil phase, depending on the W: O ratio of the HIPE. The DGMO emulsifier (Grindsted Products, Brabrand, Denmark) comprises approximately 81% diglycerol monoleate, 1% other diglycerol monoesters, 3% polyglycerols, and 15% other polyglycerol esters. This imparts a minimum water phase / water phase interfacial tension value of approximately 2.5 dynes / cm and has a typical aggregation concentration of approximately 2.9%.

To form the HIPE, the oil phase is placed in a 7.62 cm diameter plastic cup. The water phase is placed in a coated addition funnel maintained at approximately 50 ° C. The contents of the plastic cup are shaken ^ using a Cafrano RZR50 agitator equipped with a six-blade agitator that rotates at approximately 300 revolutions per minute (adjustable by the operator as necessary). The water phase is added to the oil phase in the plastic cup with constant stirring for a period of about 2 to 5 minutes. The cup is moved up and down as needed to shake the HIPE while forming to incorporate all the water phase into the emulsion so homogeneously as possible. The following are non-limiting examples of this invention, for example HIPE foams with LOI of at least 18%. In the cases where the LOI values were not available, the estimated values based on the laboratory test described in section 6, test methods, paragraph A of retardation of flames are provided (indicated as estimated). Example 1: This example illustrates the use of flame retardant monomers that are copolymerized in the backbone on the polymer network. The process from the comparative example is followed with different phases of oil as provided in Table 2, infra. In the examples where chloroprene is present, the The aqueous phase used to form the emulsion is not heated and the initial curing temperature is 45 ° C for 18 hours increasing to 65 ° C for 18 to achieve final curing. Alternatively, such emulsions are cured at 65 ° C in a pressure vessel charged with at least about 2 atmospheres pressure (from an argon tank). The suspended antimony trioxide is the ammonium phase when it is present.

Table 2 Foam Properties (W: O 40: 1 Ratio) chlorostyrene. Sb2O6 is antimony trioxide obtained from Laurel Chemicals. * The DVB used in Example 1 D was DVB55 (55% pure).

Example 2. Sample A of Example 1 aged approximately 3 weeks under ambient conditions and showed yellow discoloration on the surface exposed to fluorescent light. The LOI value obtained after the period is only 19%. A separate foam is made with the same onomer composition and Chimassorb ™ 944 showed much less discoloration over a comparable period and essentially does not decline in LOI values. Yet another variation, a HIPE foam was prepared from an oily phase comprising 20% DVB42, 75% chloroprene, 3% antimony trioxide, and 2% 4-methacryloxy-2-hydroxybenzophenone (obtainable from Polisciences of Warrington, PA) . This last compound is a UV absorber that is covalently bound in the polymer network. This foam also shows good light stability with respect to discoloration.

Example 3. This example illustrates the application of non-reactive flame retardant additives for pre-emulsification of monomer phase or for post-cure of foam in a washing step. The emulsion is made as detailed in Comparative Example A. The HIPE foam comprises the monomers 20% DVB55 and 60% styrene. The rest is a non-reactive pyrrhoretic agent that is included in the oil phase, as shown in Table 3.

Table 3 Foam Properties (W: O 40: 1 Ratio) FR Additive A = Antiblaze 125 added after curing by immersion; B = antiblock TDCP-LV; C = Declorane Plus ™ (Laurel Industries).

These foams show weight losses in TGA experiments at lower temperatures than foams in which the flame retardant additive is covalently bonded (or polymeric). Example 4. This example illustrates the consequence of the residual salt left in the foam. A foam is prepared using 17% Antiblaze TDCP / LV, 60% styrene and 20% DVB with 3% antimony trioxide in the oil phase. The wet foam is washed using 10% aqueous potassium phosphate. The resulting product has an LOI estimated at 22%. The residual salt level of the foam is about 5% by weight of calcium phosphate.

Example 5: This example illustrates the process where the foam is post-chemically treated to impart a flame retardant foam composition. A HIPE foam is prepared in a W: O ratio of 40: 1 using a monomer component consisting of 77% isoprene; 3% antimony trioxide, and 20% DVB55. The emulsion is formed at 0 ° -5 ° C and is cured under 2 atmosphere pressure at 65 ° C for 48 hours. The resulting foam is dried and washed in water and 2-propanol as described above. The foam is then exposed to bromine vapors for a period of 24 hours. The resulting foam is isolated and washed again in 2-propanol and dichloromethane to remove residual vapors. The product has an estimated LOI of 23% and a residual bromine content of 50%. Example 6. The DGMO emulsifier is modified by exposure to bromine. The dibromo-DGMO is purified by column chromatography and is used to prepare an emulsion comprising 20% DVB55, 3% antimony trioxide and 77% 4-chlorostyrene in a W: O ratio of 40: 1. The resulting foam has a estimated value LOI of 25%.

Claims (59)

1. A flame retardant open-cell polymer foam, formed by polymerization of a water-in-oil emulsion with a high internal phase. 5 comprises a continuous oil phase and a discontinuous water phase, wherein the foam has a Limiting Oxygen Index (LOI) value of at least about 18%.

2. The flame retardant polymer foam according to claim 1, characterized in that the foam has a LOI value of at least 21%.

3. The flame retardant polymer foam according to claim, claim 2, characterized in that the foam has a LOI value of at least about 23%.

4. The flame retardant polymer foam according to claim 2, characterized in that the foam has a LOI value from 15 about 21% up to about 30%.

5. The flame retardant polymeric foam according to claim 2, characterized in that the foam is prepared by polymerization of a free radical of an oil-in-water emulsion of high internal phase, wherein > the oil phase of the emulsion comprises one or more polymerizable monomers that 20 contain the flame retardance to the polymer after polymerization.

6. The flame retardant polymer foam according to claim 5, characterized in that the oil phase of the emulsion comprises one or more polymerizable monomers containing one or more of the elements chlorine, bromine, antimony, phosphorus or bromine.

7. The flame retardant polymer foam according to claim 6, characterized in that the polymerizable monomer is selected from from the group consisting of 2-chloro-1,3-butadiene (chloroprene), 2,3-dichloro-1,3-butadiene (dichloroprene), isomers of chlorostyrene, dichlorostyrene and trichlorostyrene, octachlorostyrene, pentabromophenyl acrylate; pentabromophenyl methacrylate, isomers of bromostyrene, dibromostyrene and tribromostyrene, 1,3-dibromopropyl acrylate, 2,4,6- • 5-tribromophenyl acrylate, 2-bromo-1,3-butadiene (bromoprene), 2,3-dibromo-1, 3-butadiene (dibromoprene), 3-6-dichloro-1,3,7-octatriene, vinyl dipropyl phosphate, vinyl diphenyl phosphate, tris [styryl] phosphate, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, divinyl phenyl phosphate , 2,3-dibromobutan-1,4-diol diacrylate, chlorodivinyl benzene, brominated alkylacrylates, diacrylates, triacrylates, tetracrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, and methacrylonitriles; • chlorinated alkyl acrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, methacrylonitriles thereof; halogenated styrenics and mixtures thereof.

8. The flame retardant polymer foam according to claim 7, characterized in that the polymerizable monomer is selected from the group consisting of 2-chloro-1,3-butadiene; 2,3-dichloro-1,3-butadiene; 2-bromo-1, 3-butadiene; 2,3-dibromo-1,3-butadiene; and mixtures thereof.

9. The flame retardant polymer foam according to claim 6, characterized in that the oil phase of the emulsion comprises one or 20 plus chlorine or bromine containing polymerizable monomers.

10. The flame retardant polymer foam according to claim 6, characterized in that the oil phase of the emulsion further comprises suspended antimony trioxide.

11. The flame retardant polymer foam according to claim 2, characterized in that the flame retardant material is added to the oil phase or to the water phase of the emulsion prior to emulsification or polymerization, wherein the material that confers the flame retardation is not polymerizable monomer.

12. The flame retardant polymer foam according to claim 11, characterized in that the material conferring the flame retardancy 5 comprises one or more of the elements chlorine, bromine, antimony, phosphorus or boron.

13. The flame retardant polymer foam according to claim 12, characterized in that the material that confers the flame retardance is polymeric and is added to the oil phase of the emulsion before emulsification or polymerization.

14. The flame retardant polymeric foam according to claim 13, characterized in that the material conferring the flame retardance is selected from the group consisting of polyvinyl chloride; polyvinylidene chloride; polyvinyl bromide, polyvinylidene bromide; polyvinyl diphenyl phosphate; a quaternary ammonium polymer having a counter ion selected from the group 15 which consists of hexachloroantimonate, phosphate, borate and mixtures thereof; and mixtures of them.

15. The flame retardant polymeric foam according to claim 11, characterized in that the material that confers the flame retardation is not polymeric and is added to the emulsion before emulsification or polymerization.

16. The flame retardant polymer foam according to claim 15, characterized in that the flame retardant material is selected from the group consisting of brominated and chlorinated aliphatic compounds, phosphate and phosphonate esters, borate esters and mixtures of the same.

17. The flame retardant polymer foam in accordance with 25 claim 16, characterized in that the material conferring the flame retardance is selected from the group consisting of Chloro Wax ™, decabromodiphenyl oxide, hexabromocyclododecane, tris [1,3-dichloropropyl] phosphate, bis (2-chloroethyl) 2-chloroethylphosphonate, and mixtures thereof.

18. The flame retardant polymer foam according to claim 2, characterized in that a flame retardant material is incorporated into the foam after polymerization of the emulsion, wherein the material conferring flame retardancy comprises one or more of the elements chlorine, bromine, antimony, phosphorus or boron.

19. The flame retardant polymer foam according to claim 18, characterized in that the material conferring flame retardancy is selected from the group consisting of antimony potassium tartrate, antimony capronate, antimony thioxide, antimony phosphate, salts containing antimony hexahalide; antimony trioxide; antimony trisulfide, antimony borate, ammonium phosphate, antimony polyphosphates such as pyrosphosphate, tripolyphosphate and ammonium hexametaphosphate; ammonium borate, calcium phosphate, calcium chloride, calcium bromide, calcium borate, calcium tetrachlorophthalate, sodium ethyl phosphinate, sodium borate and combinations thereof.

20. The flame retardant polymeric foam according to claim 2, characterized in that the foam comprises one or more components that impart flame retardance to the foam, wherein one or more components are included at a level of at least about 5%, in total weight of the foam.

21. The flame retardant polymeric foam according to claim 2, characterized in that it comprises an antioxidant, an UV absorbent compound or a mixture thereof.

22. The flame retardant polymer foam in accordance with claim 2, characterized in that the polymeric foam has a Tg from about -40 ° C to about 90 ° C.

23. The flame retardant polymer foam according to claim 22, characterized in that the Tg is from about 0 ° C to 5 approximately 70 ° C.

24. The flame retardant polymeric foam according to claim 2, characterized in that the foam has a density from about 12 mg / cc to about 80 mg / cc.

25. The flame retardant polymer foam according to claim 24, characterized in that the foam has a density from > about 20 mg / cc to about 80 mg / cc.

26. An open-cell, pyro-retardant polymeric foam having an Oxygen Limiting Index (LOI) value of at least about 21%, wherein the foam is formed by polymerization of a water-in-oil emulsion High internal phase comprising a continuous oil phase and a discontinuous water phase, wherein the oil phase comprises a polymerizable monomer containing one or more of the elements selected from the group consisting of chlorine, bromine, antimony , phosphorus, boron and mixtures thereof.

27. The flame retardant polymer foam according to claim 26, characterized in that the polymerizable monomer containing one or more of chlorine, bromine, antimony, phosphorus or boron is selected from the group consisting of 2-chloro-1,3. -butadiene (chloroprene), 2,3-dichloro-1,3-butadiene (dichloroprene), isomers of chlorostyrene, dichlorostyrene and trichlorostyrene, octachlorostyrene, pentabromophenyl acrylate; pentabromophenyl methacrylate, isomers of bromostyrene, dibromostyrene and 25-tribromostyrene, 1,3-dibromopropyl acrylate, 2,4,6-tribromophenyl acrylate, 2-bromo-1, 3-butadiene (bromoprene), 2,3-dibromo-1,3. -butadiene (dibromoprene), 3-6-dichloro-1, 3,7- octatriene, vinyl dipropyl phosphate, vinyl diphenyl phosphate, tris [styryl] phosphate, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, divinyl phenyl phosphate, 2,3-dibromobutan-1,4-diol diacrylate, chlorodivinyl benzene , brominated alkylacrylates, diacrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, and methacrylonitriles; chlorinated alkyl acrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, methacrylonitriles thereof; halogenated styrenics and mixtures thereof.

28. The flame retardant polymeric foam according to claim 27, characterized in that the polymerizable monomer is selected from the group consisting of 2-chloro-1,3-butadiene; 2,3-dichloro-1,3-butadiene; 2-bromo-1,3-butadiene; 2,3-dibromo-1,3-butadiene; and mixtures thereof.

29. The flame retardant polymeric foam according to claim 28, characterized in that it comprises an antioxidant, a UV absorbing compound, or a mixture thereof.

30. The flame retardant polymeric foam according to claim 26, characterized in that the oil phase of the emulsion comprises one or more of chlorine or bromine containing polymerizable monomers.

31. The flame retardant polymer foam according to claim 26, characterized in that the foam further comprises antimony trioxide.

32. The flame retardant polymeric foam according to claim 31, characterized in that the antimony trioxide is suspended in the oil phase of the emulsion prior to polymerization to form the foam.

33. The flame retardant polymeric foam according to claim 26, characterized in that the polymeric foam has a Tg from about -40 ° C to about 90 ° C.

34. The flame retardant polymeric foam according to claim 33, characterized in that the Tg is from about 0 ° C to about 70 ° C.

35. The flame retardant polymeric foam according to claim 26, characterized in that the foam has a density from about 12 to about 80 mg / cc.

36. The flame retardant polymeric foam according to claim 35, characterized in that the foam has a density from about 20 mg / cc to about 50 mg / cc.

37. The flame retardant polymeric foam according to claim 26, characterized in that the water-in-oil emulsion that is polymerized comprises: (1) a continuous oil phase comprising: (a) from about 80% to about 98% by weight of the oil phase, of a monomer component comprising: (i) at least 5% by weight of the monomer component of a monomer comprising an element selected from the group consisting of chlorine, bromine, antimony, phosphorus, boron and mixtures of the same (ii) from about 0% to about 90%, by weight of the monomer component, of a monofunctional monomer substantially water insoluble capable of forming a homopolymer having a Tg of about 40 ° C or less; (iii) from about 0% to about 70% by weight of the monomer component of a comonomer monofunctional insoluble in water capable of imparting firmness roughly equivalent to that provided by styrene; (iv) from about 5% to about 50% in • weight of the monomer component, of a first polyfunctional entanglement agent, substantially insoluble in water selected from the group consisting of divinylbenzene and analogs thereof; and (v) From about 0% to about 20% in 10 weight of a monomer component, of a second agent * of polyfunctional entanglement substantially insoluble in water from the group consisting of diacrylates and dimethacrylates of diols and analogs thereof; and (b) from about 2% to about 20% by weight of the oil phase, of an emulsifying component that is soluble in the oil phase and that is suitable to form a stable water-in-oil emulsion; (2) a discontinuous water phase comprising from about 0.1% to about 20%, by weight of the water phase, of a soluble electrolyte in 20 water; and (3) a volume to weight ratio of the water phase to the oil phase of at least about 3: 1.

38. The flame retardant foam according to claim 37, characterized in that the oil phase of the emulsion comprises from 25 about 25% up to about 80% by weight of the monomer that it comprises an element selected from the group consisting of chlorine, bromine, antimony, phosphorus, and boron and mixtures thereof.

39. The flame retardant foam according to claim 38, characterized in that the polymerizable monomer containing one or more of chlorine, bromine, antimony, phosphorus or boron is selected from the group consisting of 2-chloro-1,3-butadiene (chloroprene), 2,3-dichloro-1,3-butadiene (dichloroprene), isomers of chlorostyrene, dichlorostyrene and trichlorostyrene, octachlorostyrene, pentabromophenyl acrylate; pentabromophenyl methacrylate, isomers of bromostyrene, dibromostyrene and tribromostyrene, 1,3-dibromopropyl acrylate, 2,4,6-tribromophenyl acrylate, 2-bromo-1,3-butadiene (bromoprene), 2,3-dibromo-1, 3- butadiene (dibromoprene), 3-6-dichloro-1,3,7-octatriene, vinyl dipropyl phosphate, vinyl diphenyl phosphate, tris [styryl] phosphate, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, divinyl phenyl phosphate, 2,3-dibromobutan-1,4-diol diacrylate, chlorodivinyl benzene, brominated alkylacrylates, diacrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, and methacrylonitriles; chlorinated alkyl acrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, methacrylonitriles thereof; halogenated styrenics and mixtures thereof.

40. The flame retardant foam according to claim 39, characterized in that the foam further comprises antimony trioxide.

41. The flame retardant foam according to claim 40, characterized in that the foam further comprises an antioxidant, an UV absorbing compound or a mixture thereof.

42. A process for obtaining a flame retardant open cell polymer foam having an Oxygen Limiting Index (LOI) value of at least about 21%, the process comprising the steps of: (A) forming a water emulsion in oil from: (1) an oil phase comprising: (a) from about 80% to about 98% by weight of the oil phase, of a monomer component comprising: (i) from about 0% to about 90%, weight of the monomer component, of a monofunctional monomer substantially insoluble in water capable of forming a homopolymer having a Tg of about 40 ° C or less; (ii) from about 0% to about 70% by weight of the monomer component, by weight of a monofunctional comonomer substantially insoluble in water capable of imparting strength approximately equivalent to that provided by the styrene; (iii) from about 5% to about 50% by weight of the monomer component, of a first polyfunctional entanglement agent, substantially insoluble in water selected from the group consisting of divinylbenzene and analogs thereof; and (iv) From about 0% to about 20% by weight of a monomer component, of a second polyfunctional entanglement agent substantially insoluble in water, selected from the group consisting of diacrylates and dimethacrylates of diols and analogues of the same; Y (b) from about 2% to about 20% by weight of the oil phase, of an emulsifying component that is soluble in the oil phase and which is suitable to form a stable water-in-oil emulsion; (2) a water phase comprising from about 0.1% to about 20%, by weight of the water phase, of a soluble electrolyte 5 in water; (3) a volume to weight ratio of the water phase to the oil phase of at least about 3: 1 and (4) wherein the emulsion comprises one or more components that confer pyroretime to the polymeric foam wherein one or more components 10 are included at a level of at least about 5%, by weight 9 total of the oil phase; and (B) polymerizing the monomer component in the oil phase of the water-in-oil emulsion to form the polymeric foam material.

43. The process according to claim 42, characterized in that one or more components that confer flame retardation comprise each, one or more elements of chlorine, bromine, antimony, phosphorus or boron.

44. The process according to claim 43, characterized i because the monomer component of the oil phase of the emulsion comprises at least about 5% by weight of a monomer comprising an element 20 selected from the group consisting of chlorine, bromine, antimony, phosphorus, boron and mixtures thereof.

45. The process according to claim 44, characterized in that the polymerizable monomer containing one or more of the chlorine, bromine, antimony, phosphorus or boron elements is selected from the group consisting of 2-chloro-1, 3-butadiene (chloroprene), 2,3-dichloro-1,3-butadiene (dichloroprene), isomers of chlorostyrene, dichlorostyrene and trichlorostyrene, octachlorostyrene, pentabromophenyl acrylate; pentabromophenyl methacrylate, isomers of bromostyrene, dibromostyrene and tribromostyrene, 1,3-dibromopropyl acrylate, 2,4,6-tribromophenyl acrylate, 2-bromo-1,3-butadiene (bromoprene), 2,3-dibromo-1, 3- butadiene (dibromoprene), 3-6-dichloro-1,3,7-octatriene, vinyl dipropyl phosphate, vinyl diphenyl phosphate, tris [styryl] phosphate, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, divinyl phenyl phosphate, 2,3-dibromobutan-1,4-diol diacrylate, chlorodivinyl benzene, brominated alkylacrylates, diacrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, and methacrylonitriles; chlorinated alkyl acrylates, triacrylates, tetraacrylates and the corresponding methacrylates, acrylamides, methacrylamides, acrylonitriles, methacrylonitriles thereof; halogenated styrenics and mixtures thereof.

46. The process according to claim 43, characterized in that the oil phase of the emulsion further comprises suspended antimony trioxide.

47. The process according to claim 46, characterized in that the antioxidant is added to the emulsion formed in stage A or to the polymerized foam formed in stage B.

48. The process according to claim 43, characterized in that the ratio of volume to weight of the water phase to the oil phase is at least about 12: 1.

49. The process according to claim 43, characterized in that the volume to weight ratio of the water phase to the oil phase is from about 12: 1 to about 85: 1.

50. The process according to claim 49, characterized in that the volume to weight ratio of the water phase to the oil phase is from about 20: 1 to about 50: 1.

51. The process according to claim 43, characterized in that the material conferring the flame retardant is not a polymerizable monomer and is added to the oil phase or to the water phase to the emulsion before emulsification or before polymerization.

52. The process according to claim 51, characterized in that the material conferring the flame retardant is polymeric and is added to the oil phase before emulsification.

53. The process according to claim 52, characterized in that the material conferring the pyro-retardant is selected from the group consisting of polyvinyl chloride; polyvinylidene chloride; polyvinyl bromide; polyvinylidene bromide; polyvinyl diphenyl phosphate; a quaternary ammonium polymer having an counter ion selected from the group consisting of hexachloroantimonate, phosphate, borate and mixtures thereof; and combinations thereof.

54. The process according to claim 51, characterized in that the material conferring the flame retardant is not polymeric and is added to the emulsion before the polymerization;

55. The process according to claim 54, characterized in that the material conferring the pyro-retardant is selected from the group consisting of brominated and chlorinated aliphatic compounds, phosphate and phosphonate esters, borate ethers and mixtures thereof.

56. The process according to claim 55, characterized in that the material conferring the flame retardance is selected from the group consisting of Chioro Wax ™, decabromodiphenyl oxide, hexabromocyclododecane, tris [1,3-dichlorpropyl] phosphate, bis (2-chloroethyl) 2-chloroethylphosphonate, and mixtures thereof.

57. The process according to claim 51, characterized in that the oil phase of the emulsion further comprises suspended antimony trioxide.

58. The process according to claim 57, characterized in that an antioxidant, an UV absorbent compound or a mixture thereof is added to the emulsion formed in step (A) or to the polymerized foam formed in step (B) .

59. The polymeric foam according to claim 1, characterized in that the foam is compressible.