MXPA97005183A - Recirculation of a portion of high internal phase emulsions prepared in a conti procedure - Google Patents

Abstract

The present invention relates to an improvement in a continuous process for making high internal phase emulsions which are typically polymerized to provide microporous, open cell polymeric foam materials capable of absorbing aqueous fluids, especially aqueous body fluids, such as urine . The improvement involves the recirculation of a portion (approximately 50% or less) of the emulsion removed from the dynamic mixing zone of this continuous process. This increases the uniformity of the emulsion finally obtained from this continuous process in terms of having water droplets homogeneously dispersed in the oil phase. This also improves the stability of the HIPE and expands the temperature scale to empty and cure this HIPE during the subsequent emulsion polymerization.

Description

REC1RCULAC1QN OF A PORTION OF HIGH INTERNAL PHASE EMULSIONS PREPARED IN A CONTINUOUS PROCEDURE FIELD OF THE INVENTION This application relates to an improvement in a continuous process for making high internal phase emulsions which are typically polymerized to provide microporous, open cell, polymeric foam materials capable of absorbing aqueous fluids, especially aqueous body fluids such as urine. This application particularly relates to a continuous process for making high internal phase emulsions, wherein a portion of the prepared emulsion is recirculated to provide uniformity in the formation of such emulsions.

BACKGROUND OF THE INVENTION Water-in-oil emulsions having a relatively high ratio of water phase to oil phase are known in the art as High Internal Phase Emulsions (hereinafter referred to as "HIPE" or HIPEs). HIPEs have radically different properties of emulsions of low or medium internal phase ratio types. Due to these radically different properties, HIPEs have been used in applications such as fuels, oil exploration, agricultural sprays, textile printing, food, domestic and industrial cleaning, solid transport, fire extinguishers, and advance control, to name only some. HIPEs of the water-in-oil emulsion type have found use in various areas such as cosmetics and drugs, and in foods such as dietetic products, desserts and dressings. Water-in-oil HIPEs have also been used in emulsion polymerization to provide polymeric, porous foam type materials. See, for example, United States of America patent 3,988,508 (Lissant), issued October 26, 1976; Patent of the United States of America 5,149,720 (DesMarais et al.), issued September 22, 1992; U.S. Patent 5,260,345 (DesMarais et al.), issued November 9, 1993; and U.S. Patent 5,189,070 (Brownscombre et al.) issued February 23, 1993. The dispersed droplets present in the HIPEs deform from the usual spherical shape to polyhedral shapes and lock in place. For this reason, HIPEs are sometimes referred to as "structured" systems and exhibit unusual theological properties that are generally attributed to the existence of polyhedral drops. For example, when HIPEs are subjected to sufficiently low levels of shear stress, they behave as elastic solids. As the level of the shear stress increases, a point is reached where the polyhedral drops begin to slide together, so that the HIPE begins to flow. This point is called the deformation value. When said emulsions are subjected to an increased high shear stress, they exhibit a non-Newtonian behavior, and the effective viscosity is rapidly reduced. The difficulty in preparing HIPEs is partly due to these unusual Theological properties. The internal and external phases of the HIPE are by themselves of relatively low viscosity, but as the emulsion is formed, its viscosity becomes very high. When a small amount of liquid with a low viscosity is added to this high viscosity liquid, it is difficult to incorporate homogeneously with conventional mixing systems. Without proper mixing, and as more liquid of low viscosity is added, the highly viscous phase tends to break up and form a coarse dispersion in the thinner liquid. For this reason, HIPEs have been very difficult to prepare. However, with the correct type and degree of mixing, the low viscosity liquid can be adequately dispersed within the high viscosity liquid, as it is added to form a stable emulsion. The original procedures for manufacturing HIPEs were continuous procedures that have economic disadvantages in a commercial production situation. These batch processes typically involve the preparation of a dispersion having a low internal phase portion and subsequently adding more internal phase until the HIPE contains more than 75% internal phase. Such procedures are problematic, but can be easily employed using conventional mixing equipment. The most continuous emulsification equipment used to prepare emulsions of low and medium internal phase ratio. It is not suitable for preparing HIPEs. This is because this equipment: (1) does not provide a sufficient deformation force to the structured systems to move the polyhedral drops beyond one another and, therefore, the desired mixing is not achieved; or (2) produces shear velocities in excess of the inherent shear stability point. Of greater importance, said equipment does not provide adequate mixing, particularly when there is a great disparity in the viscosities of the two phases. An attempt to develop a continuous process for the production of HIPEs is described in U.S. Patent 3,565,817 (Lissant), issued February 23, 1971, and is directed to obtain sufficient mixing providing shear rates high enough to reduce the effective viscosity of the emulsified mass near the viscosities of the less viscous internal and external phases. However, for certain types of emulsions, it is not possible to apply sufficient shear to effect an apparent viscosity close to that of the external and internal phases without going above the shear stability point of the emulsion. Low-fat spreads (margarine) are examples of such emulsions. Although a variety of structuring elements can achieve sufficient shear rates to reduce the effective viscosity of the emulsion phase close to the external and internal phase viscosities (thus allowing the phases to be mixed to a certain degree), such elements are not always they provide complete mixing as can be seen by the presence of some non-emulsified liquid in the HIPE. U.S. Patent 4,844,620 (Lissant et al.), Issued July 4, 1989, also describes a continuous system for preparing HIPEs of internal and external phases having highly fired viscosities. The internal and external phase ingredients are forced through shear by means of a device 20 through recirculation means 18. A recirculation loop 16 is adapted to provide partial recirculation of the processed phase materials, so that they exit from the device for applying shear stress, so that the recirculation means expel a larger portion of processed materials through the recirculation loop for additional steps through the system (The remaining portion of the processed phase materials is continuously driven from the loop 16). , as usable HIPE The reason for recirculation to appear appears to be to provide a preformed emulsion having the desired ratio of internal to external phase materials continuously circulating through loop 16. See column 3, lines 39, 41. See also , United States of America 4,472,215 patent (Binet et al.), issued on September 18 September 1984, which describes a procedure for making HIPE continuous for the manufacture of an explosive water-in-oil emulsion precursor, where at least 80%, and up to 95% by volume of the thick HIPE is expelled to through a loop of recirculation by means of a pump and then it returns to be passed again through the static mixer. A continuous process for preparing HIPE, useful in emulsion polymerization, is described in U.S. Patent No. 5,149,720 (DesMarais et al.), Issued September 22, 1992. In this continuous HIPE process, streams of Separate water and oil phase feedings are introduced into a dynamic mixing zone (typically a pin impeller), and then subjected to agitation with sufficient shear in the dynamic mixing zone at least to partially form a mixture emulsified while maintaining fixed flow rates, without pulses, for the oil and water phase currents. The weight ratio of water to oil of the feed streams fed to the dynamic mixing zone is stably increased at a rate that does not break the emulsion in the dynamic mixing zone. The emulsified contents of the dynamic mixing zone are continuously removed and continuously fed into a static mixing zone to be subjected to further agitation of suitable shear stress to form a stable HIPE. This HIPE, which contains the monomer components in the oil phase, is particularly suitable for emulsion polymerization to provide absorbent polymeric foams. Since the oil and water phase currents are combined in this dynamic mixing zone, according to the United States of America patent 5,149,720, there is a transition point at the front of this zone, where the currents of oil and water go from the two separate phases to an emulsified phase. As the path velocity of the oil and water phase currents through this dynamic mixing zone increases, it has been found that the degree of this transition point also increases. As a result, the water phase is less homogeneously dispersed in the oil phase, and the resulting HIPE comprises water droplets having a less uniform size. This makes the HIPE less stable during the subsequent emulsion polymerization, especially if the pouring or curing temperatures used are relatively high, for example, at least about 65 ° C. The cells formed in the resulting polymeric foam also have a less uniform size. Therefore, it may be desirable to be able to make a HIPE, and especially a HIPE suitable for emulsion polymerization: (1) continuously; (2) with greater uniformity of dispersion of the water phase in the oil phase; (3) superior productions; (4) with higher capacity to empty or cure HIPE at higher temperatures during emulsion polymerization.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to an improved continuous process for obtaining high internal phase emulsions (HIPEs), and particularly HIPEs useful for making polymeric foams. This method comprises the steps of: A) providing a liquid, oil phase feed stream comprising an effective amount of a water-in-oil emulsifier; B) provide a liquid, liquid phase feed stream; C) simultaneously entering the water and oil phase feed streams into a dynamic mixing zone at flow rates such that the initial weight ratio of water phase to oil phase is on the scale of approximately 2: 1 at about 10: 1; D) subjecting the combined feed streams in the dynamic mixing zone to sufficiently stir under shear stress to partially form an emulsified mixture of the dynamic mixing zone; E) continuously withdrawing the emulsified mixture from the dynamic mixing zone; F) recirculating from about 10 to about 50% of the withdrawn emulsified mixture to the dynamic mixing zone; G) continuously introducing the remaining withdrawn emulsified mixture into a static mixing zone, wherein the remaining emulsified mixture is subjected to high shear mixing sufficient to completely form a stable, high internal phase emulsion having a phase weight ratio of water to oil of at least about 4: 1; and H) continuously removing the high, stable internal phase emulsion from the static mixing zone. When the oil phase stream comprises one or more monomers capable of forming a polymeric foam, when the water phase stream comprises an aqueous solution containing from about 0.2% to 20% by weight of water soluble electrolyte, and when the The oil or water phase stream comprises an effective amount of a polymerization initiator, the resulting high, stable internal phase emulsion can be polymerized to form a polymeric foam. The key improvement in the continuous process of the present invention is the recirculation of a portion of the HIPE formed in the dynamic mixing zone. It is believed that said recirculation modifies the degree of the transition point of the separated water and oil phases to the HIPE in the dynamic mixing zone. This also improves the uniformity of the emulsion which finally exits the static mixer, the water droplets being homogeneously dispersed in the continuous oil phase. This improves the stability of the HIPE and expands the temperature scale to empty and cure this HIPE during the subsequent emulsion polymerization. Recirculation can provide other benefits, including: (a) superior HIPE production throughout the entire procedure; and (b) the ability to formulate HIPEs having much higher water-to-oil phase ratios, for example, as high as approximately 250: 1. In fact, HIPEs made through the process of the present invention can easily obtain very high water-to-oil phase ratios of from about 150: 1 to about 250: 1. Since the process of the present invention is particularly suitable for making HIPEs useful for preparing polymeric foams, it is also useful for making other HIPEs of the water-in-oil type. These include agricultural products such as agricultural sprays, textile processing additives, such as textile printing pastes, food products such as salad dressings, creams and margarines, household and industrial cleaning products, such as cleaners, wax polishers, and silicone polishers, cosmetics such as insect repellent creams, antiperspirant creams, tanning creams, hair creams, cosmetic creams, and acne creams, transportation of solids through pipes, advance control products, fire extinguishing products , and similar.

BRIEF DESCRIPTION OF THE DRAWING The Figure is a side sectional view of the apparatus and equipment for carrying out the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION I. HIPE Components of the Oil Phase and Water Phase A. In General The process of the present invention is useful for preparing certain water-in-oil emulsions having a relatively high ratio of water phase to oil phase. , and are commonly known in the art, as "HIPEs". These HIPEs can be formulated to have a relatively wide scale of water-to-oil phase relationships. The particular water to oil phase ratio selected will depend on a number of factors, including the particular oil and water phase components present, the particular use that the HIPE will have, and the particular properties desired for the HIPE.

Generally, the water to oil phase ratio in the HIPE is about 4: 1, and typically is in the range of about 4: 1 to 250: 1, preferably from about 12: 1 to about 200: 1, and very typically from 20: 1 to 150: 1, approximately. For the preferred HIPEs according to the present invention which are subsequently polymerized to provide polymeric foams (hereinafter referred to as "HIPE foams"), the relative amounts of the water and oil phases used to form the HIPE are, among many other parameters, important to determine the structural, mechanical and performance properties of the resulting HIPE foams. In particular, the relationship of the water-in-oil phase in the HIPE can influence the density, cell size, and capillarity of the foam, as well as the dimensions of the poles that form the foam. The HIPEs according to the present invention used to prepare these foams will generally have water to oil phase ratios in the range of about 12: 1 to about 250: 1, preferably from about 20: 1 to about 200: 1, most preferably from 25: 1 to 150: 1, approximately.

B. Oil Phase Components 1. The Oil The oil phase of HIPE can comprise a variety of oily materials. The particular oily materials selected will often depend on the particular use that will be made of the HIPE. By "oily" is meant a material, solid or liquid, but preferably liquid at room temperature that broadly meets the following requirements: (1) it is hardly soluble in water; (2) has a low surface tension; and (3) has a characteristic greasy feel. Furthermore, for those situations where the HIPE is going to be used in the food, drug or cosmetic area, the oily material must be cosmetically and pharmaceutically acceptable. Materials contemplated for use to make HIPEs in accordance with the present invention may include, for example, various oil compositions comprising straight, branched and / or cyclic paraffins, such as mineral oils, petrolatums, isoparaffins, squalanes; vegetable oils, mineral oils and marine oils such as palo oil, oitici oil, castor oil, linseed oil, poppy seed oil, soybean oil, cottonseed oil, corn oil, fish oil, oils walnut, pine seed oil, olive oil, coconut oil, palm oil, canola oil, rapeseed oil, sunflower seed oil, safflower oil, sesame seed oil, peanut oil, and the like; esters of fatty acids or alcohols such as ethyl hexyl palmitate, fatty alcohol di-isooctanoates of C16 to Q8, fibutyl phthalate, diethyl maleate, tricresyl phosphate, acrylate or methacrylate esters, or the like; Resin oils and wood distillates including turpentine distillates, calophonic spirits, pine oil, and acetone oil; various petroleum-based products such as gasolines, naphthas, fuel gas, lubricating oils and heavier oils; coal distillates including benzene, toluene, xylene, naphtha solvent, creosote oil and anthracene oil and ethereal oils: and silicone oils. Preferably, the oily material is n? polar. For preferred HIPEs that polymerize to form polymeric foams, this oil phase comprises a monomer component. In the case of HIPE foams, suitable for use as absorbents, this monomer component is typically formulated to form a copolymer having a glass transition temperature (Tg) of about 35 ° C or less, and typically 15 ° to about 30 ° C. (The method for determining Tg by Dynamic Mechanical Analysis (DMA) is described in the Test Methods section of the co-pending United States of America application No. 08/370922 (Thomas A. DesMarais et al.), Submitted on January 10, 1995. Case No. 5541, which is incorporated herein by reference). This monomer component includes: (a) at least one monofunctional monomer whose atactic amorphous polymer has a Tg of about 25 ° C or less; (b) optionally a monofunctional comonomer; (c) at least one polyfunctional entanglement agent. The selection of particular types and amounts of monofunctional monomers and comonomers and polyfunctional crosslinking agents may be important for the performance of HIPE absorbent foams having the desired combination of structure, mechanical, and fluid handling properties, which make that such materials are suitable for use as absorbers for aqueous fluids. For HIPE foams useful as absorbers, the monomer component comprises one or more monomers that tend to impart rubber-like properties to the resulting polymeric foam structure. Such monomers can produce high molecular weight atactic amorphous polymers (greater than 10,000) having Tgs of about 25 ° C or less. Monomers of this type include, for example, monoenes such as (C4-C14) alkyl acrylates, such as butyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate. , (lauryl) dodecyl acrylate, isodecyl acrylate, tetradecyl acrylate, aryl acrylates, and alkaryl acrylates such as benzyl acrylate, nonylphenyl acrylate, alkyl (C6-C16) alkyl methacrylates such as hexyl acrylate, octyl methacrylate , nonyl methacrylate, decyl methacrylate, isodecyl methacrylate, dodecyl (lauryl) methacrylate, tetradecyl methacrylate, (C4-C12) alkylstyrenes such as pn-octylstyrene, acrylamides such as N-octadecyl acrylamide, and polyenes such as 2- methyl-1,3-butadiene (isoprene), butadiene, 1,3-pentadiene (piperylene), 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 1,3-nonadiene, 1,3- decadiene, 1,3-undecadiene, 1,3-dodecadiene, 2-methyl-1,3-hexadiene, 6-methyl-1,3-hept adieno, 7-methyl-1, 3-octadiene, 1, 3,7, -octatriene, 1, 3,9-decatpene, 1, 3,6-octatriene, 2,3-dimethyl-1,3-butadiene, 2 -methyl-3-ethyl-1,3-butadiene, 2-methyl-3-propyl-1,3-butadiene, 2-amyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 2,3 -dimethyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 2-methyl-3-propyl-1, 3-pentadiene, 2,6-dimethyl-1,3,7-octatriene , 2,7-d? Methyl-1, 3,7-octatriene, 2,6-dimethyl-1,3,6-octatriene, 2,7-dimethyl-1,3,6-octatriene, 7-methyl? -3-met? Len-1, 6-octadiene (myrcene), 2,6-dimethyl-1,5,7-octatriene (ocimene), 3,8-nonadienoate of 1-methyl-2-vinyl-4,6 heptadiene, 5-methyl-1, 3,6-heptatriene, 2-ethyl butadiene, and mixtures of these monomers. Of these monomers, the most preferred are isodecyl acrylate, n-dodecyl acrylate, and 2-ethylhexyl acrylate.

Generally, the monomer will comprise from 30 to 85%, most preferably from 50 to 70%, by weight, of the monomer component. For HIPE foams useful as absorbers the monomer component typically comprises one or more components that are typically included to modify the properties of the Tg of the resulting polymeric foam structure, its modulus (strength), and its firmness. These types of monofunctional comonomer may include styrene-based comonomers (eg, styrene and ethylstyrene) or other types of monomers such as methyl methacrylate, wherein the related homopolymer is well known for its illustrative firmness. Of these comonomers, the particularly preferred ones are styrene, ethylstyrene and mixtures thereof, to impart firmness to the resulting polymeric foam structure. These comonomers can comprise up to about 40% of the monomer component and will normally comprise from about 5 to 40%, preferably from about 10 to about 35%, and most preferably from about 15 to about 30% by weight of the monomer component. For HIPE foams as an absorbent, this monomer component also includes one or more polyfunctional crosslinking agents. The inclusion of these entanglement agents tends to increase the Tg of the resulting polymeric foam as well as its strength with a resulting loss of flexibility and elasticity. Suitable entanglement agents include any of those which can be employed in elastic interlacing diene monomers, such as divinylbenzenes, divinyl toluenes, divinylxylenes, divinylnaphthalenes, divinyl alkylbenzenes, divinylphenanthrenes, trivinylbenzenes, divinylbiphenyls, divinyl diphenylmethanes, divinylbenzyl, divinylphenolyl ethers, divinyl diphenyl, divinylfurans, divinyl sulfone, divinyl sulfide, divinyl dimethylsilane, 1, 1'-divinyl ferrocene, 2-vinylbutadiene, maleate, di-, tri-, tetra-, penta-, or higher (meth) acrylates and di (meth) acrylamides. , tri-, tetra-, penta-, or higher, including ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, dimethacrylate 2-butanediol, diethylene glycol dimethacrylate, hydroquinone dimethacrylate, catechol dimethacrylate, resorcinol dimethacrylate, dimethate triethylene glycol crilate, polyethylene glycol dimethacrylate; trimethylol propane trimethacrylate, pentaerythritol tetramethacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, hydroquinone diacrylate, catechol diacrylate, resorcinol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate; pentaerythritol tetra-acrylate, 2-butenediol diacrylate, tetramethylene diacrylate, trimethylolpropane triacrylate, pentaerythritol tetra-acrylate, N-methylol acrylamide, 1,2-ethylenebisacrylamide, 1,4-butanedisopyclamide, and mixtures thereof. Preferred polyfunctional crosslinking agents include divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 2-butenediol dimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate. , 2-butenediol diacrylate, trimethylolpropane triacrylate and trimethacrylate and mixtures thereof. Typically, divinylbenzene is available as a mixture with ethylstyrene in proportions of about 55:45. These proportions can be modified in order to enrich the oil phase with one or the other component. Generally, it is advantageous to enrich the mixture with the ethylstryrene component, while at the same time omitting the styrene inclusion from the monomer mixture. The preferred ratio of divinylbenzene to ethylstyrene is approximately :70 to 55:45, most preferably from 35:65 to 45:55, approximately. The inclusion of higher levels of ethylstyrene imparts the required firmness without increasing the Tg of the resulting copolymer to the extent that styrene does. The entanglement agent can generally be included in the phase of. HIPE oil in an amount of about 5 to about 40%, preferably about 10 to 13%, and most preferably about 15 to 30%, by weight of the monomer component (100% base). The major portion of the oil phase of these preferred HIPEs will comprise these monomers, comonomers and entanglement agents. It is essential that these monomers, comonomers and entanglement agents are substantially insoluble in water so that they are mainly soluble in the oil phase and not in the water phase.

The use of such substantially water insoluble monomers ensures that HIPE will obtain appropriate characteristics and stability. Of course, it is greatly preferred that the monomers, comonomers and interlacing agents used herein are of the type that the resulting polymeric foam is suitably non-toxic and appropriate and chemically stable. These monomers, comonomers and entanglement agents should preferably have little or no toxicity if they are present at very low residual concentrations during the processing of the foam after polymerization and / or use. 2. Emulsifying Component Another essential component of the oil phase is an emulsifier (or emulsifiers) that allows the formation of stable HIPE emulsions. Suitable emulsifiers for use herein may include any number of conventional emulsifiers applicable for use in low and medium internal phase emulsions. The particular emulsifiers used will depend on a number of factors, including the particular oily materials present in the oil phase, and the particular use that will be given to the HIPE. Usually, these emulsifiers are non-ionic materials and can have a wide range of HLB heats. Examples of some typical emulsifiers include sorbitan esters such as sorbitan laurates (eg, SPAN® 20), sorbitan palmitates (eg, SPAN® 40), sorbitan stearates (eg, SPAN®). 60 and SPAN® 65), sorbitan mono-oleates (eg, SPAN® 80), sorbitan trioleates (eg, SPAN® 85), sorbitan sesquiolates (eg.

EMSORB® 2502), and sorbitan isostearate; polyglycerol esters and ethers (see, TRIODAN® 20); polyoxyethylene fatty acids, esters and ethers such as polyoxyethylene (2) oleyl ethers, polyethoxylated oleyl alcohols (eg, BRIJ® 92 and SIMUSOL® 92); etc., mono-, di- and triphosphoric esters such as mono-, di- and triphosphoric esters of oleic acid (eg, HOSTAPHAT KC300N), polyoxyethylene sorbitol esters such as polyoxyethylene sorbitol hexastates (eg, ATLAS®). G-1050), fatty acid esters of ethylene glycol, mono-180 glycerol stearates (eg, IMWITOR 780K), glycerol ethers and fatty alcohols (eg, CREMOPHOR WO / A), esters of polyalcohols, ethylene oxide condensates of synthetic primary alcohols (eg, SYNPERONIC A2), mono- and diglycerides of fatty acids (eg ATMOS® 300), and the like. For the preferred HIPEs that are polymerized to make polymeric foams, the emulsifier can serve for other functions in addition to stabilizing the HIPE. These include the ability to hydrophilize the resulting polymeric foam. The resulting polymer foam is typically washed and dewatered to remove most of the water and other residual components. This residual emulsifier can, if sufficiently hydrophilic, make the hydrophobic foam otherwise sufficiently wettable in order to be able to absorb aqueous fluids. For preferred HIPEs that are polymerized to make polymeric foams, suitable emulsifiers can include sorbitan monoesters of C16-C24 grade acids, linear unsaturated Q6-2 fatty acids, and saturated linear de-fatty acids, such as sorbitan monooleate , sorbitan monomiristato and sorbitan monoesters derived from coconut fatty acids; diglycerol monoesters of branched C16-C24 fatty acids, linear unsaturated C16-C22 fatty acids, or saturated linear C12-C14 fatty acids, such as diglycerol monooleate (ie, glycerol monoesters of C18: 1 fatty acids) , diglycerol monomiristat, diglycerol monoisostearate, and diglycerol monoesters of coconut fatty acids; diglycerol monoaliphatic ethers of branched C16-C24 alcohols (eg, Guerbet alcohols), linear unsaturated Q-g alcohols, and saturated linear C12-C14 alcohols (eg coconut fatty alcohols), and mixtures of these emulsifiers. See, application of the co-pending United States of America series No. 989,270 (Dyer et al.), Filed December 11, 1992 (incorporated herein by reference, which describes the composition and preparation of suitable polyglycerol ester emulsifiers, and application for patent of the United States of America co-pending series No. 08/370920 (Stephen A. Goldman et al.), filed on January 10, 1995, case No. 5540 (incorporated herein by reference), which describes the composition and preparation of suitable polyglycerol ether emulsifiers Preferred emulsifiers include sorbitan monolaurate (eg, SPAN® 20, preferably greater than about 40%, preferably greater than about 50%, and most preferably greater than about 70% monolaurate of sorbitan), sorbitan monooleate (see, SPAN® 80, preferably greater than about 40%, preferably greater than about 50%, and most preferably greater than about 70% sorbitan monooleate), diglycerol monooleate (v. g., preferably greater than about 40%, preferably greater than about 50%, and most preferably greater than 70% glycerol monooleate), diglycerol monoisostearate (eg, preferably about 40%, preferably greater than about 50%, and most preferably greater than about 70% diglycerol monoisostearate), diglycerol monomyristate (eg, preferably greater than about 40%, preferably greater than about 50%, and most preferably greater than about 70%). % of sorbitan monomiristate), cocoyl ethers (eg, lauryl and myristoyl diglycerol, and mixtures thereof) In addition to these primary emulsifiers, co-emulsifiers may optionally be included in the oil phase. emulsifiers are at least cosolubles with the primary emulsifier in the oil phase.The co-emulsifiers can be of zwitterionic types, including phosphatidyl hills and compositions containing phosphatidyl choline such as aliphatic lecithins and betaines such as lauryl betaine, cationic types, including long chain C 12 -C 22 dialiphatic dialiphatic quaternary ammonium salts of short chain C, -C 4, such as dimethyl ammonium ditallow chloride , bistridecyl dimethyl ammonium chloride, and ditallow dimethyl ammonium methyl sulfate, dialkyl (alkenoyl) -2-hydroxyethyl long chain C12-C22 quaternary ammonium salts, and short chain C, -C4 dialiphatic salts, such as ditallowyl-2-hydroxyethyl dimethyl ammonium chloride, long chain C12-C22 dialiphatic imidazolinium ammonium salts such as methyl-1-tallow amino-2-tallow imidazolinium methyl sulfate and methyl-1-methyl sulfate oleyl-amino-ethyl-2-oleyl-imidazolinium, dialkyl-quaternary benzyl quaternary ammonium salts of C ^ Q, short chain, long chain C12-C22 monoaliphatic such as dimethyl stearyl benzyl ammonium chloride and dimethyl chloride tallow benzyl ammonium, the quaternary ammonium salts of dialkoyl (alkenoyl) -2-aminoethyl of long-chain C12-C22, monoaliphatic of C C., short-chain, aliphatic monohydroxy of short-chain CrC4, such as methobisulfate of Disteboyl- 2-aminoethyl methyl 2-hydroxypropyl ammonium and dioleoyl-2-aminoethyl methyl 2-hydroxyethyl ammonium methyl sulfate; anionic types including dialiphatic esters of sodium sulfosuccinic acid such as the dioctyl ester of sodium sulfosuccinic acid and the bistridecyl ester of sodium sulfosuccinic acid, the amine salts of dodecylbenzenesulfonic acid; and mixtures of these secondary emulsifiers. Preferred secondary emulsifiers are dimethyl ammonium ditallow methylisulfate and dimethyl ammonium dimethyl chloride. When these optional secondary emulsifiers are included in the emulsifying component, this is typically in a primary to secondary emulsifier ratio of from about 50: 1 to about 1: 4, preferably from about 30: 1 to about 2: 1. 3, Oil Phase Composition The oil phase used to form the HIPE according to the process of the present invention may comprise varying ratios of oily materials and emulsifiers. The particular relationships selected will depend on a number of factors including the oily materials involved, the emulsifier used, and the use that will be given to the HIPE. Generally, the oil phase may comprise from about 50 to about 98% by weight of oily materials, and from about 2 to about 50% by weight of emulsifier. Typically, the oil phase will comprise from about 70 to about 97% by weight of the oily materials, and from about 3 to about 30% by weight of the emulsifier, and more typically from about 85 to 95%, by weight of the materials oily, and from about 3 to about 15% by weight of emulsifier. For the preferred HIPEs used to make polymeric foams, the oil phase will generally comprise from about 65 to about 98% by weight of the monomer component and from about 2 to about 35% by weight of the emulsifier component. Preferably, the oil phase will comprise from about 80 to 97% by weight of the monomer component, and from 3 to about 20% by weight of the emulsifier component. Most preferably, the oil phase will comprise from about 90 to 97% by weight of the monomer component, and from about 3 to about 10% by weight of the emulsifier component. In addition to the monomer and emulsifier components, the oil phase of these Preferred HIPEs may 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 5,290,820 (Bass et al.), Issued on the 1st. March 1994, which is incorporated herein by reference. Another possible optional component is a solvent substantially insoluble in water for the monomer and emulsifier components. The use of said solvent is not preferred, but if employed, it will generally comprise no more than about 10% by weight of the oil phase. A preferred optional component is an antioxidant such as a Disabled Amine Light Stabilizer (HALS), such as bis- (1, 2,2,5,5-pentamethylpiperidinyl) sebacate (Tinuvin 765) or a Stored Phenolic Stabilizer (HPS). ) such as Irganox 1076 and t-butyl hydroxyquinone. Another preferred optional component is a plasticizer such as dioctyl azelate, dioctyl sebacate or dioctyl adipate. Other optional components include fillers, dyes, fluorescent agents, opacifying agents, chain transfer agents and the like.

C. Components of the Water Phase The internal water phase of the HIPE is generally an aqueous solution containing one or more dissolved components. A dissolved or essential component of the water phase is a water-soluble electrolyte. The dissolved electrolyte minimizes the tendency of the components in the oil phase to dissolve also in the water phase. For the preferred HIPEs used to make polymeric foams, it is believed that it minimizes the degree to which the polymeric material fithe cell windows in the adjoining oil / water surfaces formed by the droplets of the water phase during the polymerization. In this way, the presence of the electrolyte and the ionic strength resulting from the water phase is believed to determine whether the degree of the resulting preferred HIPE foams can be of open cell.

Any electrolyte capable of imparting ionic resistance to the water phase can be used. Preferred electrolytes are mono-, di-, or trivalent inorganic salts, such as water-soluble halides, v. gr., chlorides, nitrates and sulfates of alkali metals and alkaline earth metals. Examples include sodium chloride, calcium chloride, sodium sulfate and magnesium sulfate. For HIPEs that are used to make polymeric foams, calcium chloride is most preferred for use in the process according to the present invention. Generally, the electrolyte will be used in the water phase of the HIPE at a concentration in the range from about 0.2 to about 20% by weight of the water phase. Most preferably, the electrolyte will comprise from about 1 to about 10% by weight of the water phase.

For HIPEs used to make polymeric foams, a polymerization initiator is typically included in the HIPE. Said initiator component can be added to the water phase of the HIPE and can be any conventional water-soluble free radical initiator. These include peroxygen compounds such as sodium, potassium and ammonium persulfates, hydrogen peroxide, sodium peracetate, sodium percarbonate and the like. Conventional redox initiator systems can also be used. Such systems are formed by combining the above peroxygen compounds with reducing agents such as sodium bisulfite, L-ascorbic acid or ferrous salts. The initiator may be present up to about 20 mole% based on the total moles of the polymerizable monomers in the oil phase. Preferably, the initiator is present in an amount of about 0.001 to 10 mol% based on the total moles of polymerizable monomers in the oil phase.

II. Continuous Procedure for Making HIPE The continuous process of the present invention for making the HIPE includes the following steps: A) introducing the oil phase and water phase feed streams into the dynamic mixing zone (and initially the recirculation zone); B) initially forming the emulsion in the dynamic mixing zone (and the recirculation zone); C) forming the HIPE in the dynamic mixing zone; and D) transferring the effluent from the dynamic mixing zone to the static mixing zone. See, United States of America patent 5,149,720 (DesMarais et al.), Issued September 22, 1992, which is incorporated herein by reference. Since this description of the continuous process of the present invention will be with reference to making the preferred HIPEs useful for obtaining polymeric foams, it should be understood that this process can be used to prepare other HIPEs of the water type in aceile using different components and amounts of the oil and water phase, by appropriate modification of the process, and the like. A. Initial Introduction of the Oil and Water Phase Feed Currents to the Dynamic Mixing and Recirculation Zones The oil phase can be prepared in any suitable manner by combining the essential and optional components using conventional techniques. Said combination of components may be carried out in any continuous or intermittent manner, using any appropriate order of addition of components. The oil phase thus prepared will generally be formed and stored in a feed tank, then provided as a feed stream at a desired flow rate. The water phase stream can be prepared and stored in a similar manner. The liquid streams of both the oil and water phases are initially combined by simultaneously introducing these feed streams together into a dynamic mixing zone. During this initial combination stage of these oil and water phases, the flow rates of the feed streams are set so that the initial weight ratio of the water phase to the oil phase being introduced to the zone of Dynamic mixing is below that final weight ratio of the HIPE produced through the process. In particular, the flow rates of the oil phase and water currents are set such that the weight ratio of the oil to water phase during this initial introduction cap is in the range of about 2: 1 to about 10: 1, most preferably from about 2.5: 1 to about 5: 1. The purpose of combining the oil and water phase currents at these lower water-to-oil ratios is to allow the formation, in the dynamic mixing zone, of at least some amount of water-in-oil emulsion, which is relatively stable and can not easily "break" under the conditions found in this area. The actual flow rates of the liquid oil and water phase liquid streams during this initial introduction stage into the dynamic mixing zone will vary depending on the scale of operation involved. For operations at pilot plant scale, the flow rate of the oil phase during this initial introduction stage may be in the range of about 0.02 to about 0.35 liters / minute, and the flow rate of the water phase may be on the scale of approximately 0.04 to approximately 2.0 liters / minutes. For commercial scale operations, the oil phase flow rate during this initial introduction step may be in the range of about 10 to about 25 liters / minute, and the flow rate of the water phase may be in the scale from about 20 to about 250 liters / minute. During the initial startup stage of this procedure, the dynamic mixing and recirculation zones are filled with the liquid from the oil and water phase before stirring begins. During this filling stage, the displaced gas is vented from the dynamic mixing zone. Before initiating agitation, the liquid in these zones is typically in two separate phases, i.e., an oil phase and a water phase. (At lower water-to-oil ratios, spontaneous emulsification may occur, so that essentially only one phase exists). Once the dynamic mixing zone is filled with the liquid, stirring is started, and the emulsion begins to form in the dynamic mixing zone. At this point, the flow rates of the oil and water phase, towards the dynamic mixing zone, must be set in order to provide a relatively low initial water to oil weight ratio within the scale previously described. The recirculation zone must also be set by approximating the sum of the introductory speeds of the oil and water phase, as previously described.

B. Initial Emulsion Formation in the Dynamic Mixing Zone As noted above, the feed streams of the oil and water phase are initially combined by simultaneous introduction to the dynamic mixing zone (and in the recirculation zone during the initial filling). For the purposes of the present invention, the dynamic mixing zone comprises a containment container for the liquid components. This container is equipped with means for imparting agitation under shear stress to the liquid contents of the container. The means for imparting agitation under shear stress must cause agitation or mixing beyond which it arises by virtue of a simple flow of liquid material through the vessel. The means for imparting agitation under shear stress may comprise any apparatus or device imparting the requisite amount of shear agitation to the liquid contents in the dynamic mixing zone. A suitable type of apparatus for imparting agitation under shear stress is a pin driver comprising a cylindrical arrow from which a number of rows (flights) of cylindrical pins extend radially. The number, dimensions and configuration of the pins in the impeller shaft can vary widely, depending on the amount of agitation under shear stress that is desired to impart to the liquid contents in the dynamic mixing zone. A pin driver of this type can be mounted within a generally cylindrical mixing vessel, which serves as the dynamic mixing zone. The impeller shaft is generally placed parallel to the direction of liquid flow through the cylindrical vessel. Agitation under shear stress is provided by rotating the impeller shaft at a speed, which imparts the appropriate degree of agitation under shear stress to the liquid material passing through the vessel. See Figure 2 of the United States of America patent 5,149,720. The agitation under shear stress in the dynamic mixing zone is sufficient to form at least some of the liquid contents in the water-in-oil emulsion, having water-to-oil phase relationships within the previously established scales. Frequently said agitation under shear stress, at this point, will typically be in the range of about 1000 to about 10,000 sec "1, very typically from 1500 to 7000 sec" 1, approximately. The amount of agitation under shear does not need to be constant, but it can be varied with the time necessary to effect said emulsion formation. As indicated, not all the material of the water and oil phase that has been introduced to the mixing zone dynamic at this point, it needs to be incorporated into the water-in-oil emulsion, provided that at least some of the emulsion of this type (e.g., the emulsion comprises at least about 90% by weight of the liquid effluent of the dynamic mixing zone) is formed and flows through the dynamic mixing zone In the continuous process described in the patent of the United States of America ,149,720, it is taught that it is important that the flow rates of both the oil and water phase are stable and that once again stir without pulses to avoid sudden or precipitate changes that may cause the emulsion formed in the zone of dynamic mixed break. See column 9, lines 31-35. An important advantage of the improved method according to the present invention is that the critical aspect of stable, pulse-free flow rates is substantially reduced using a recirculation zone as described below. In fact, it has been found that the flow of the oil phase can be stopped for a period, provided that the recirculation rate is sufficient to provide a sufficient return of emulsified oil phase, so that the total oil phase ratio (not emulsified / emulsified) in this recirculation flow to the introduced water phase does not exceed the stabilizing capacity of the emulsifier.

C. HIPE Formation in the Dynamic Mixing Zone After a water-in-oil emulsion was formed in the dynamic mixing zone, having a relatively low water to oil ratio, the emulsion is converted, together with the contents no additional emulsified, to the HIPE. This is accomplished by altering the relative flow rates of the water and oil phase streams that are fed into the dynamic mixing zone. Said increase in the water to oil ratio of the phases can be achieved by increasing the flow rate of the water phase, reducing the flow rate of the oil phase or through a combination of these techniques. The water to oil ratios that will eventually be obtained, through said adjustment of the flow rates of the water phase and / or oil phase will generally be in the range of about 12: 1 to about 250: 1, very typically from about 20: 1 to about 200: 1, and more typically from about 25: 1 to 150: 1. The adjustment of the flow rates of the oil and / or water phase to increase the water to oil phase ratio, which is fed into the dynamic mixing zone, can begin immediately after the initial formation of the emulsion. Generally this will happen as fast as agitation has started in the dynamic mixing zone. The duration it takes increases the water to oil phase ratio to the highest ratio finally desired, it will depend on the scale of the procedure involved and the magnitude of the final water to oil phase ratio that will be achieved. Frequently, the duration of the flow rate adjustment period necessary to increase the water to oil phase ratios will be in the range of about 1 to about 5 minutes. The actual rate of increase in the water to oil phase ratio of the streams being fed to the dynamic mixing zone will depend on the particular components of the emulsion being prepared, as well as on the scale of the process involved. For any given HIPE formula and procedure setting, the stability of the emulsion can be controlled simply by verifying the nature of the process effluent to ensure that it comprises at least some material (eg, at least 90% of the effluent). total) in substantially HIPE form. The conditions within the dynamic mixing zone during the formation of the emulsion can also affect the nature of the HIPE prepared through this process. One aspect that can impact the character of the HIPE produced is the temperature of the emulsion components within the dynamic mixing zone.

Generally, the emulsified contents of the dynamic mixing zone should be maintained at a temperature of about 95 ° C, most preferably from about 35 ° to about 90 ° C, during the formation of the HIPE. An important advantage of the improved process according to the present invention (in relation to that described in the patent of the United States of America) ,149,720) is the ability to increase the temperature at which a uniform HIPE can be made by a continuous process. This is due to the addition of the recirculation zone (as described below), where a portion of the HIPE, from the dynamic mixing zone, is recirculated and combined with the oil and water phase streams introduced to the dynamic mixing zone. Another aspect involves the amount of shaking under shear imparted to the contents of the dynamic mixing zone and after adjusting the flow rates of the water and oil phase. The amount of shaking under shear imparted to the emulsified material in the dynamic mixing zone will directly impact the size of the dispersed water droplets (and finally the size of the cells making the polymeric foam). For a given group of types and ratios of emulsion component, and for a given combination of flow rates, subjecting the liquid contents of the dynamic mixing zone to greater amounts of shear agitation will tend to reduce the size of the dispersed water droplets. Foam cells, and especially cells that are formed by polymerizing an oil phase containing monomer surrounding water phase droplets relatively free of monomer, will often have a substantially spherical shape. The size or diameter) of said substantially spherical cells is thus a parameter commonly used to characterize foams in general, as well as to characterize polymeric foams of the type prepared from HIPE made through the process of the present invention. Since the cells in a given sample of polymeric foam will not necessarily be approximately equal in size, an average cell size (diameter) will usually be specified. A number of techniques are available to determine the average cell size in foams. These techniques include mercury porosimetry methods, which are well known in the art. However, the most useful technique for determining cell size in foams involves a simple photographic measurement of a foam sample. Such a technique is described in greater detail in U.S. Patent 4,788,225 (Edwards et al.), Issued November 29, 1988, which is incorporated herein by reference. For the purposes of the present invention, the average cell size of foams made by polymerizing this HIPE, can be used to quantify the amount of shear agitation imparted to the emulsified contents in the dynamic mixing zone. In particular, after the flow rates of the oil and water phase have been adjusted to provide the proper water / oil ratio, the emulsified contents of the dynamic mixing zone must be subjected to agitation under shear stress, the which is sufficient to finally form a HIPE which, after the subsequent polymerization, provides a foam having an average cell size of about 5 to about 100 μm. Most preferably, said agitation will be that suitable to obtain an average cell size, in the subsequently formed foam of about 10 to 90 am. Typically, this will represent an agitation under shear stress of from about 1000 to about 10,000 sec "1, most preferably from 1,500 to 7,000 sec" 1, approximately. As with the shear agitation used after the initial introduction of the oil and water phases into the dynamic mixing zone, the agitation under shear to provide the HIPE need not be constant during the process. For example, the speeds of the impeller can be increased or decreased during the preparation of the HIPE, as desired or required, to provide emulsions that can form foams having the desired characteristics, particular to the average particle size, described above. During the adjustment period, the recirculation is adjusted to approximate the actual velocity of the total flow of the introductory oil and water phases. In this way, when the target oil and water phase flow rates are achieved, approximately half of the effluent exiting the dynamic mixing zone is removed and passed through the recirculation zone. Then, the flow velocity through the recirculation zone can be conveniently reduced Transfer of the Effluent from the Dynamic Mixing Zone to the Static Mixing Zone In the process of the present invention, the liquid contents containing the emulsion of the dynamic mixing zone are continuously removed, and a portion is introduced into a mixing zone. static, where they undergo additional mixing and agitation. Of course, the nature and composition of this effluent will change over time as the process continues on its initial start, towards the initial emulsion formation, towards the formation of HIPE in the dynamic mixing zone, as the relationship of water to oil phase is increased. During the initial start-up procedure, the effluent from the dynamic mixing zone may contain little or no emulsified material. After the emulsion formation was initiated, the effluent from the dynamic mixing zone will comprise a water-in-oil emulsion having a relatively low water-to-oil phase ratio, together with an excess of oil phase and oil phase material. water that has not been incorporated into the emulsion. Finally, after the water-to-oil phase ratio of the two feed streams has been increased, the effluent from the dynamic mixing zone will mainly comprise HIPE, together with relatively small amounts of oil phase and water materials that have not been incorporated into this HIPE. Once the steady state operation is achieved, the flow velocity of the effluent, from the dynamic mixing zone to the static mixing zone, will be equal to the sum of the flow velocities of the water and oil phases that are being processed. entering the dynamic mixing zone. After the water and oil phase flow rates have been appropriately adjusted to provide for the formation of the desired HIPE, the flow velocity of the effluent, from the dynamic mixing zone, will typically be on the scale of approximately 35 to approximately 800 liters per minute for commercial scale operations. For pilot plant scale operations, the flow velocities of the effluent from the dynamic mixing zone will typically be in the range of about 0.8 to about 9.0 liters per minute. The static mixing zone also provides resistance to the flow of liquid material through the process and thus provides back pressure to the liquid contents of the dynamic mixing zone. However, the primary purpose of the static mixing zone is to subject the emulsified material from the dynamic mixing zone to further agitation and mixing in order to complete the formation of the stable HIPE. For the purposes of the present invention, the static mixing zone may comprise any containment container suitable for liquid materials. This container is internally configured to impart agitation or mixing to said liquid materials as these materials flow through the container. A typical static mixer is a spiral mixer which may comprise a tubular device having an internal configuration in the form of a series of propellers that reverse the direction every 180 ° of helical twisting. Each 180 ° twist of the internal helical configuration is known as a flight. Typically, a static mixer having 12 to 32 helical flights, intersecting at 90 ° angles, will be useful in the method herein. In the static mixing zone, the shear forces are imparted to the liquid material simply by the effect of the internal configuration of the static mixing device in the liquid as it flows through it. Typically, said shear stress is imparted to the liquid contents of the static mixing zone to a degree of from about 1000 to about 10,000 sec "1, most preferably from 1000 to 7000 sec" 1, approximately. In the static mixing zone, essentially all the material of the water and oil phase which has not been previously incorporated into the emulsion will be formed, after obtaining water / oil phase ratios of HIPE, in a stable HIPE. Typically, such HIPEs will have a water-to-oil phase ratio, which is in the range of about 12: 1 to about 250: 1, typically from about 20: 1 to about 200: 1, very typically from 25: 1 to 150 : 1, approximately. Such emulsions are stable in the sense that they will not be significantly separated in their water and oil faces, at least for a period sufficient to allow the polymerization of the monomers present in the oil phase. lll. Recirculation of the HIPE Portion of the Dynamic Mixing Zone As noted above, a key aspect of the improved continuous process according to the present invention is the addition of a recirculation zone. In this recirculation zone, a portion of the emulsified mixture removed from the dynamic mixing zone is recirculated and then combined with the oil and water phase streams that are introduced to the dynamic mixing zone, as previously described. By recirculating a portion of the removed emulsified mixture, the uniformity of the HIPE which ultimately exits the static mixer is improved, especially in terms of having water droplets homogeneously dispersed in the continuous oil phase.

Recirculation can also allow high HIPE production through both dynamic and static mixing zones, as well as allow the HIPE formulation to have higher water-to-oil phase ratios. The particular amount of HIPE that is recirculated will depend on a variety of factors, including the particular components present in the oil and water phases, the rate at which the oil and water phase streams are introduced into the zone of water. dynamic mixing, the speed at which the emulsified mixture is removed from the dynamic mixing zone, the particular production desired through the mixing zones both dynamic and static, and similar factors. For the purposes of the present invention, about 10 to 50% of the emulsified mixture withdrawn from the dynamic mixing zone is recirculated. In other words, the ratio of the recirculated stream to the combined oil phase and water phase streams, input to the dynamic mixing zone is from about 0.11: 1 to about 1: 1. Preferably, approximately 15 to 40% of the emulsified mixture withdrawn from the dynamic mixing zone is recirculated (recirculated current ratio to combined oil phase and water phase currents of about 0.17: 1 to about 0.65: 1). Most preferably, about 20 to 33% of this emulsified mixture withdrawn is recirculated (recirculated current ratio to combined oil phase and water phase currents of about 0.25: 1 to about 0: 1: 1). The recirculated portion of the removed emulsified mixture is returned to the dynamic mixing zone at a point, so that it can be combined with the oil and water phase streams being introduced to the dynamic mixing zone. Typically, this recirculated portion of the emulsified mixture (the recirculated stream) is pumped to a point that is close to the point where the oil and water phase streams enter the dynamic mixing zone. The means used to pump this recirculated stream must not induce shear stress greater than that previously described for the dynamic mixing zone. In fact, it is typically preferred that these pumping means induce relatively low shear stress to this recirculated stream. The volume of the emulsified components present in the recirculated stream, in relation to the total volume of the oil and water phase components present in the dynamic mixing zone, can be important. For example, the volume of recirculated current can affect the degree of stabilization of the emulsion present in the dynamic mixing zone, especially if the rate of introduction of the oil phase current to the dynamic mixing zone is reduced or stopped as described above. Conversely, the higher the recirculation current volume, the less likely the continuous process will be for changes in HIPE flow rates or composition. For production systems that intend to operate for substantial periods to make only a particular type of HIPE, a relatively large recirculated current volume is recommended, i.e., the volume of recirculated current is in the order of about 2 to about 10 times the total volume of the oil and water phase components present in the dynamic mixing zone. For systems that require a substantially faster response to changes in the flow rate or composition of HIPE, a relatively smaller recirculated current volume is preferred, ie, the recirculated current volume is in the range of about 0.3 to about 3. times the total volume of oil and water phase components present in the dynamic mixing zone. Further, if the length of the recirculation zone, through which this recirculated stream passes, is substantially greater than the length of the dynamic mixing zone, v. g., about twice the length, the inclusion of static mixing elements in the recirculation zone may be desirable. This is particularly important to avoid the development of the emulsified components on the interior surfaces of ducts, pipes, etc., which are used to transport this recirculated stream through the recirculation zone. A suitable apparatus for carrying out the improved continuous process of the present invention is shown in the figure, and is generally indicated as 10. The apparatus 10 has a molding block generally indicated as 14. The phase and oil phase currents of water are fed from tanks (not shown) to block 14. These oil and water phase currents enter through a conduit 18 formed in block 14. A valve indicated generally with 22, controls the flow of these ingredients of oil phase and water to conduit 26 or conduit 30 formed in block 14.

Actually, the relative position of the valve 22 determines whether the currents determine whether the phase and oil streams flow through the conduit 26, as shown in the figure, or flow into the conduit 30. The conduit 30 feeds the streams. of oil phase and liquid to the head 32 of the dynamic mixing vessel, generally indicated 34. This vessel 34 is equipped with a vent line (not shown) for venting the air during filling of the vessel 34 to maintain all the environmental liquid in this container. This dynamic mixing vessel has a hollow cylindrical housing indicated with 38 within which a pin driver 42 rotates. The pin driver 42 consists of a cylindrical arrow 46 and a number of cylindrical impeller pin flights 50 that exit radially outwardly. this arrow These flights of pins 50 are placed in four rows running along a portion of the length of the arrow 46, the rows being positioned at 90 ° angles around the circumference of this arrow. The rows of pins 50 are offset along the length of the arrow 46, so that the flights that are perpendicular to each other are not in the same radial plane extending from the central axis of the arrow 46. A representative impeller 42 it may consist of an arrow 46 having a length of about 18 cm and a diameter of about 1.9 cm. This arrow supports four rows of cylindrical pins 50, each having a diameter of 0.5 cm and extending radially outward from the central axis of arrow 42 to a length of 1 cm. This impeller 42 is mounted inside a cylindrical housing 38, so that the pins 50 have a gap of 0.8 mm from their internal surface. This impeller can be operated at a speed of 300 to 3000 rpm, approximately. The impeller 50 is used to impart shaking agitation to the liquid contents present in the dynamic mixing vessel 34 to form the emulsified mixture. This emulsified mixture is removed from the dynamic mixing vessel through the housing cone 54, where one end of the housing 38 is fixed.

A portion of the withdrawn emulsified mixture is then recirculated through the recirculation zone, generally indicated at 58. This recirculation zone has an elbow-shaped coupling 62, one end of which is fixed within the receiving cone 54 for receiving that portion of the emulsified mixture that will be recirculated. The other end of the coupling 62 is connected to one end of a hose or conduit 66. The other end of the hose or conduit 66 is connected to a pumping device indicated as 70. A particularly suitable pumping device, which imparts a low Shear stress to this recirculated stream is a Waukesha Lobe pump. As shown in the figure, this Waukesha pump has elements 74 and 76 that pump the recirculated current through the recirculation zone, while at the same time imparting only a low shear stress. The other end of the pump 70 is connected to one end of a hose or conduit 80. The other end of hose or conduit 80 is connected to one end of the coupling 84. The other end of the coupling is connected to the housing 38 of the mixing vessel dynamic, so that the recirculated stream of zone 58 is introduced near the head 30 of this container. The remaining portion of the removed emulsified mixture that is not recirculated is subjected to further stirring or mixing in a static mixing vessel indicated as 88. One end of the static mixing vessel 88 receives the remaining portion of the emulsified mixture leaving the vessel. dynamic mixing 34. A suitable static mixer (length 35.5 cm x 1.27 cm outer diameter per 1.09 cm internal diameter) is equipped with an internal helical configuration of mixing elements, in order to provide backpressure to the dynamic mixing container 34. This helps keep the container 34 filled with liquid contents. This static mixer 88 ensures a complete and proper formation of the HIPE from the oil and water phases. The HIPE of this static mixer 88 is then removed through the end 92 for further processing, such as emulsion polymerization.

IV. Polymerization of HIPE to Obtain Polymeric Foams HIPE can be continuously withdrawn from the static mixing zone at a rate approaching or equal to the sum of the flow velocities of the water and oil phase streams fed to the zone of dynamic mixed After the water-to-oil phase ratio of the fed materials has been increased within the desired HIPE scale, and steady-state conditions have been obtained, the effluent from the static mixing zone will essentially comprise a HIPE emulsion stable suitable for further processing to an absorbent foam material. In particular, preferred HIPEs containing a polymerizable monomer component can be converted to polymeric foams. Polymeric foams of this type and especially their use as absorbents in absorbent articles, are described in, for example, US Pat. No. 5,268,224 (DesMarais et al.), Issued December 7, 1993, and the patent application. of the United States of America co-pending Series No. 989,270 (Dyer et al.), filed on December 11, 1992, both incorporated herein by reference. This HIPE can be converted to a polymeric foam through the following additional steps: A) polymerize / cure the HIPE under suitable conditions to form a solid polymeric foam structure; B) optionally washing the polymeric foam to remove the original waste water phase thereof and, if necessary, treating the foam with a hydrophilizing surfactant and / or hydratable salt to deposit any hydrophilizing surfactant / hydratable salt necessary; and C) then dehydrate this polymeric foam.

A. Polymerization / Healing of HIPE The formed HIPE will generally be collected or emptied into a suitable container, container or reaction region, which will be polymerized or cured. In one embodiment, the reaction vessel comprises a tray constructed of polyethylene, from which finally the polymerized / cured solid foam material can be easily removed for further processing after the polymerization / cure has been carried out to the desired degree. It is usually preferred that the temperature at which the HIPE is emptied into the vessel is approximately equal to the polymerization / cure temperature. Suitable polymerization / curing conditions will vary depending on the monomer and other development of the oil and water phases of the emulsion (especially the emulsifier systems used), and the type and amounts of polymerization initiators used. Frequently, however, suitable polymerization / cure conditions will involve maintaining the HIPE at elevated temperatures approximately above 30 ° C, preferably above 35 ° C, for a period ranging from about 2 to 64 hours , most preferably from 4 to 48 hours, approximately. HIPE can also be cured in stages as described in U.S. Patent 5,189,070 (Brownscombe et al.), Issued February 23, 1993, which is incorporated herein by reference. When more robust emulsifier systems such as diglycerol monooleate, diglycerol isostearate or sorbitan monooleate are used in these HIPEs, the polymerization / condition conditions can be performed at higher temperatures of about 50 ° C or higher, most preferably around 60 ° C or higher. Typically, HIPE can be polymerized / cured at a temperature of about 60 ° C to about 99 ° C, more typically about 65 ° to 95 ° C. An open-cell, porous, water-filled HIPE foam is typically obtained after polymerization / cure in a reaction vessel, such as a tray. This polymerized HIPE foam is typically cut or sliced into a sheet-like shape. Polymerized HIPE foam sheets are easier to process during the subsequent steps of treatment / washing and dehydration, as well as to prepare the HIPE foam for use in absorbent articles. The polymerized HIPE foam is typically cut / sliced to provide a cut thickness in the range from about 0.08 to about 2.5 cm. During subsequent dehydration, this can lead to crushed HIPE foams having a thickness in the range of about 0.008 to about 1.25.

B. Treatment / Washing of HIPE Foam The solid polymerized HIPE foam formed will generally be filled with the wastewater phase material to prepare the HIPE. The wastewater phase material (generally an aqueous electrolyte solution, residual emulsifier, and polymerization initiator) must be at least partially removed prior to the processing and use of the foam. The removal of this original water phase material will usually be done by compressing the foam structure to compress the residual liquid, and / or by washing the foam structure with water or other aqueous washing solutions. Frequently, several compression and washing steps will be used, v. gr., from 2 to 4 cycles. After the original water phase material has been removed to the required degree, the HIPE foam, if needed, can be treated, v. g., by continuous washing, with an aqueous solution of a hydrophilizing surfactant and / or suitable hydratable salt. When these foams are to be used as absorbers for aqueous fluids such as spills of juice, milk, and the like, for cleaning and / or body fluids such as urine and / or menstruation, they generally require additional treatment to make the foam relatively more hydrophilic. Hydrophilization of the foam, if necessary, can generally be achieved by treating the HIPE foam with a hydrophilizing surfactant. These hydrophilicizing surfactants may be any material that improves the water wettability of the polymeric foam surface. These are well known in the art, and include a variety of surfactants, preferably of the non-ionic type. Generally, they will be in liquid form, and will dissolve or disperse in a hydrophilizing solution that is applied to the HIPE foam surface. In this way, the hydrophilizing surfactants can be absorbed by the preferred HIPE foams in suitable amounts so that their surfaces become substantially hydrophilic, but without substantially damaging the desired flexibility and compression deflection characteristics of the foam. Such surfactants may include all those previously described for use as the oil phase emulsifier for HIPE, such as diglycerol monooleate, sorbitan monooleate and diglycerol monoisostearate. In preferred foams, the hydrophilizing surfactant is incorporated so that residual amounts of the agent, which remain in the foam structure, are on the scale from about 0.5% to about 15%, preferably from about 0.5 to about 6% by weight of the foam. Another material that is typically incorporated into the foam structure of HIPE is a water soluble, hydratable, and preferably hygroscopic or deliquescent inorganic salt. Such salts include, for example, toxicologically acceptable alkaline earth metal salts. Salts of this type and their use with oil-soluble surfactants such as the foam hydrophilizing surfactant are described in greater detail in U.S. Patent 5,352,711 (DesMarais), issued October 4, 1994, the description of which is incorporated herein by reference. Preferred salts of this type include calcium halides such as calcium chloride. (As previously observed, these salts can also be used as the electrolyte of the water phase in the formation of the HIPE). The hydratable inorganic salts can be incorporated by treating the foams with aqueous solutions of such salts. These salt solutions can generally be used to treat the foams after the end of or as part of the removal procedure of the residual water phase of the just polymerized foams. The treatment of foams with said solutions preferably deposits hydratable inorganic salts such as calcium chloride in residual amounts of at least 0.1% by weight of the foam, and typically on the scale of around 0.1 to 12%. The treatment of these foams and relatively hydrophobic with hydrophilicizing surfactants (with or without hydratable salts) will typically be carried out to the extent necessary to impart a suitable hydrophilic character to the foam. Some preferred HIPE foams, however, are suitably hydrophilic in preparation, and may have sufficient amounts of hydratable salts incorporated therein, thus requiring no further treatment with hydrophilizing surfactants or hydratable salts. In particular, such preferred HIPE foams include those wherein certain previously described oil phase emulsifiers and calcium chloride are used in the HIPE. In those cases, the surfaces of internal polymerized foam will be adequately hydrophilic, and will include residual water phase liquid containing or depositing sufficient amounts of chloride, even after the polymeric foams have been dehydrated to a practicable liking.

C. Foam Dehydration After the HIPE foam has been treated / washed, it will generally be dehydrated. Dehydration can be achieved by compressing the foam (preferably in the z direction) to squeeze the waste water, subjecting the foam and water at the same temperature from about 60 ° to about 200 ° C, or by microwave treatment, by thermal dehydration to vacuum or by a combination of compression and drying / microwave / vacuum dehydration techniques. The dehydration step will generally be performed until the HIPE foam is ready to use and is as dry as practicable. Frequently, such compression dehydrated foams will have a water content (moisture) of from about 50 to about 500%, most preferably from about 50 to 200% by weight, on a dry weight basis. Subsequently, the compressed foams can be thermally dried to a moisture content of about 5 to about 40%, most preferably 5 to 15% by weight, about a dry weight basis.

V. Uses of Polymeric Foams Made through a Procedure Improved Continuous A. In General Polymeric foams made in accordance with the improved continuous process of the present invention are widely used in a variety of products. For example, these foams can also be used as absorbers of environmental waste oil; as absorbent components in bandages or bandages; to apply paint to various surfaces; in heads of molasses for dust; in wet mopping heads; in fluid jets; in packaging; as odor / moisture absorbers; on cushions; and for many other uses.

B. Absorbent Articles Polymeric foams made in accordance with the improved continuous process of the present invention are particularly useful as absorbent members for various absorbent articles. See, application of the co-pending United States of America series No. 08/370922 (Thomas A. DesMarais et al.), Filed on January 10, 1995. Case No. 5541, and application of the co-pending United States of America series No. 08/370695 (Keith J. Stone et al.), Filed on January 10, 1995. case No. 5544 (incorporated herein by reference), which describe the use of these absorbent foams as absorbent members in absorbent articles. By "absorbent article" is meant a product of the consumer that is capable of absorbing significant amounts of urine, or other fluids (ie, liquids), such as aqueous fecal matter (accelerated evacuations), discarded by an incontinent user or user of the item. Examples of such absorbent articles include disposable diapers, incontinence garments, catamenials such as tampons and sanitary napkins, disposable training pants, night pads, and the like. The absorbent foam structures herein are particularly suitable for use in articles such as diapers, incontinent pads or garments, protective clothing, and the like. In its simplest form, such absorbent articles only need to include a backsheet, typically and relatively impervious to liquid, and one or more absorbent foam structures associated with this backsheet. The absorbent foam structure and the backsheet will be associated in such a way that the absorbent foam structure is located between the backsheet and the fluid discharge region of the wearer of the absorbent article. The liquid-impermeable backsheets can comprise any material, eg, polyethylene or polypropylene, having a thickness of about 0.038 mm, which will help retain the fluid within the absorbent article. More conventionally, these absorbent articles will also include a liquid-permeable top sheet element that covers the side portion of the absorbent article that touches the wearer's skin. In this configuration, the article includes an absorbent core comprising one or more absorbent foam structures positioned between the backsheet and the topsheet. The liquid permeable upper sheets can comprise any material such as polyester, polyolefin, rayon and the like, which is substantially porous and allows the body fluid to pass easily through and into the underlying absorbent core. The top sheet material will preferably not be prone to hold the aqueous fluids in the contact area between the topsheet and the wearer's skin.

SAW. Specific Examples EXAMPLE 1 Preparation of HIPE and Foams from a HIPE A. Preparation of HIPE Anhydrous calcium chloride (36.32 kg) and potassium persulfate (189 g) were dissolved in 378 liters of water. This provides the water phase stream that will be used in a continuous process to form a HIPE emulsion. To a combination of monomer comprising distilled divinylbenzene (40% divinylbenzene and 60% ethylstyrene) (2100 g), 2-ethylhexyl acrylate (3300 g), and hexanediol diacrylate (600 g) was added a monooleate emulsifier of diglycerol (360 g), and Tinuvin 765 (30 g). The diglycerol monooleate emulsifier (Grindsted Products; Bradrand, Denmark) comprises approximately 81% diglycerol monooleate, 1% other diglycerol monoesters, 3% polyglycerols, and 15% other polyglycerol esters. After mixing, this combination of materials allowed to settle during the night. No visible residue was formed, and the entire mixture was removed and used as the oil phase in a continuous process to form a HIPE emulsion. The separated currents of the oil phase (25 ° C) and the water phase (53 ° -55 ° C) were fed to a dynamic mixing apparatus. The complete mixing of the combined streams in the dynamic mixing apparatus was achieved through a pin impeller. The pin propellant comprises a cylindrical arrow with a length of approximately 21.6 cm with a diameter of approximately 1.9 cm. The arrow holds 4 rows of pins, two rows having 17 pins and two rows having 16 pins, each having a diameter of 0 5 cm extending out from the central axis of the arrow to a length of 1.6 cm. The pin propeller is mounted on a cylindrical sleeve which forms the dynamic mixing apparatus, and the pins have a clearance of 0.8 mm from the walls of the cylindrical sleeve. A smaller proportion of the effluent leaving the dynamic mixing apparatus is removed and enters a recirculation zone, as shown in the figure. The Waukesha pump, in the recirculation zone, returns the smaller portion to the point of entry of the oil and water phase flow streams to the dynamic mixing zone. A spiral static mixer is mounted downstream of the dynamic mixing apparatus to provide back pressure in the dynamic mixer and to provide improved incorporation of the components in the emulsion that is ultimately formed. The static mixer (TAH Industries Model 070-821, modified by a cut of 6.1 cm of its original length) has a length of 35.6 cm with an external diameter of 1.3 cm. The fixing of the combined mixing apparatus is filled with oil phase and water phase at a ratio of three parts of water to one part of oil. The dynamic mixing apparatus is vented so that air can escape while the apparatus is fully filled. The flow rates during filling are 3.78 g / sec of oil phase and 11.35 cc / sec of water phase with approximately 15 cc / sec of recirculation. Once the apparatus is full, the flow rate of the water phase is cut in half to reduce the pressure buildup while the vent closes. Agitation begins in the dynamic mixer, with the propeller spinning at 1800 rpm. The flow rate of the water phase was then increased steadily at a rate of 45.4 cc / sec over a period of about 1 minute, and the flow rate of the oil phase was reduced to 0.757 g / sec over a period of approximately 2 minutes. The recirculation rate was stably increased to approximately 45 cc / sec during the last period. The back pressure created by the dynamic and static mixers at this point is 69 kPa. The speed of the Waukesha pump was then stably reduced to produce a recirculation velocity of approximately 11 cc / sec.

B. Polymerization of HIPE The HIPE flowing from the static mixer at this point is collected in a round polypropylene tray, with a diameter of 43 cm and a height of 10 cm, with a concentric insert made of Celcon plastic. The insert has a diameter of 12.7 cm at its base and a diameter of 12 cm in its upper part and a height of 17.1 cm. The trays containing HIPE are kept in a room at 65 ° C for 18 hours, to carry out the polymerization and form the foam.

C. Foam Washing and Dehydration Cured HIPE foam is removed from the healing trays. The foam at this point has a residual water phase (containing dissolved emulsifiers, electrolyte, initiator residues, and initiator) about 50-60 times (50-60X) the height of the polymerized monomers. The foam was sliced with a sharp reciprocating saw blade, in sheets with a thickness of 0.406 cm. These sheets were then subjected to compression in a series of two porous press rolls equipped with a vacuum, which gradually reduces the residual water phase content of the foam to approximately 6 times (6X) the height of the polymerized material. At this point, the sheets were then restored with a 1.5% CaCl2 solution at 60 ° C, compressed in a series of 3 porous press rolls equipped with vacuum at a water phase content of about 4X. The CaCl2 content of the foam is between 8 and 10%.

The foam remained compressed after a final compression to a thickness of approximately 0.053 cm. The foam was then dried in air for approximately 16 hours. Said drying reduced the moisture content to approximately 9-175 by weight of the polymerized material. At this point, the foam sheets are very hanging. In this crushed state, the density of the foam is approximately 0.14 g / cc.

EXAMPLE 2 Preparation of HIPEs Under Various Operating Conditions HIPEs are continuously prepared from an oil phase stream consisting of a monomer component having 40% divinylbenzene (50% purity) and 60% acrylate. -ethylhexyl. to which was added diglycerol monooleate (6% by weight of the monomers) and Tinuvin 765 (0.5% by weight of the monomers). These HIPEs are prepared with the apparatus shown in the figure, using the operating conditions shown in Table 1 below.

TABLE 1 EXAMPLE 3 Preparation of HIPEs Under Various Operating Conditions HIPEs are continuously prepared from an oil phase stream consisting of a monomer component having 35% divinylbenzene (40% purity), 55% acrylate 2 -ethylhexyl and 10% hexanediol diacrylate, to which was added diglycerol monooleate (5% by weight of the monomers), dimethyl ammonium methylisulfate (1% by weight of the monomers) and Tínuvin 765 (0.5% by weight) of the monomers). These HIPEs are prepared with the apparatus shown in the figure, using the operating conditions shown in Table 2 below.

TABLE 2

Claims (9)

1. - A continuous process for the preparation of a high internal phase emulsion, said process comprises: A) providing a liquid oil phase feed stream, comprising an effective amount of a water-in-oil emulsifier; B) provide a liquid, liquid phase feed stream; C) simultaneously entering the liquid feed streams into a dynamic mixing zone at flow rates such that the initial weight ratio of water phase to oil phase is in the range of 2: 1 to 10: 1, preferably 2.5: 1 to 5: 1; D) subjecting the combined feed streams in the dynamic mixing zone to sufficiently stir under shear stress to partially form an emulsified mixture of the dynamic mixing zone; E) continuously withdrawing the emulsified mixture from the dynamic mixing zone; said method characterized in that it comprises the additional steps of: F) recirculating from 10 to 50%, preferably from 15 to 40%, most preferably from 20 to 33% of the emulsified mixture withdrawn to the dynamic mixing zone before step (D); G) continuously introducing the remaining withdrawn emulsified mixture into a static mixing zone, wherein the remaining emulsified mixture is subjected to high shear mixing sufficient to completely form a stable, high internal phase emulsion having a phase weight ratio of water to oil of at least about 4: 1, preferably from 12: 1 to 250: 1, rnuy preferably from 20: 1 to 150: 1; and H) continuously removing the high, stable internal phase emulsion from the static mixing zone.

2. The process according to claim 2, further characterized in that the oil phase comprises from 50 to 98%, preferably from 70 to 97% by weight of oily materials, and from approximately 2 to approximately 50%, preferably from 3 to 30% by weight of emulsifier,

3. The process according to claim 3 further characterized in that: 1) the oil phase stream of step (A) comprises: a) from 65 to 98%, preferably from 80 to 97%, most preferably from 90 to 97% by weight of a monomer component capable of forming a polymer foam; and b) from 2 to 35%, preferably from 3 to 20%, most preferably from 3 to 10% by weight of an emulsifying component, which is soluble in the oil phase and which is suitable for forming a water emulsion in stable oil; 2) the water phase stream of step (B) comprises an aqueous solution which contains from 0.2% to 20% by weight of water soluble electrolyte; and 3) one of the oil phase and water phase streams comprises an effective amount of a polymerization initiator.

4. The method according to claim 3 further characterized in that it comprises. i) from 30 to 85% by weight of at least one substantially water-insoluble monomer capable of forming an atactic amorphous polymer having a Tg of 25 ° C or less; ii) from 0 to 40% by weight of at least one monofunctional comonomer substantially insoluble in water; and iii) from 5 to 40% by weight of at least one polyfunctional entanglement agent substantially insoluble in water.

5. The process according to claim 3, further characterized in that the monomer component comprises: i) from 50 to 70% by weight of a monomer selected from the group consisting of butyl acrylate, hexyl acrylate. octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, isodecyl acrylate, tetradecyl acrylate, hexyl acrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, isodecyl methacrylate, methacrylate of dodecyl, tetradecyl methacrylate, pn-octylstyrene, isoprene, 1,3-butadiene, 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 1,3-nonadiene, 1,3-decadiene, 1,3-undecadiene, 1,3-dodecadiene, 2-methyl-1,3-hexadiene, 6-methyl-1,3-heptadiene, 7-methyl-1,3-octadiene, 1, 3,7, -octatriene, 1, 3,9-decatriene, 1, 3,6-octatriene, 2,3-dimethyl-1,3-butadiene, 2-amyl -1, 3-butadiene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 2-methyl-3 -propyl-1,3-pentadiene, 2,6-dimethyl-1,3,7-octatriene, 2,7-dimethyl-1,3,7-octatriene, 2,6-dimethyl-1,3,6-octatriene , 2,7-dimethyl-1, 3,6-octanediene, 7-methyl-3-methylene-1,6-octadiene, 2,6-dimethyl-1, 5,7-octatriene, 3,8-nonadienoate of 1 methyl-2-vinyl-4,6-heptadiene, 5-methyl-1,3,6-heteratriene, 2-ethyl-butadiene, and mixtures thereof; ii) from 5 to 40% by weight of a monomer selected from the group consisting of styrene, ethylstyrene, methyl methacrylate and mixtures thereof; and iii) from 10 to 30% by weight of an entanglement agent selected from the group consisting of divinylbenzenes, divinyl toluenes, divinylxylenes, divinylnaphthalenes, divinylethylbenzenes, divinifenanthrenes, trivinylbenzenes, divinylbiphenyls, divinyl diphenylmethanes, divinylbenzyl, divinylphenyl ethers, divinyldiphenyl sulfides, divinylfurans, divinyl sulfone, divinyl sulfide, divinyldimethylsilane, 1, 1'-divinylferrocene, 2-vinylbutadiene, ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butanediol dimethacrylate, diethylene glycol dimethacrylate, hydroquinone dimethacrylate, dimethacrylate catechol, resorcinol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, diacrylate of tetramethylene, trimethacrylate ilol propane, pentaerythritol tetra-acrylate, N-methylolacrylamide, N-methylolmethacrylamide, 1,2-ethylene bisacrylamide, 1,4-butane bisacrylamide, and mixtures thereof.

6. The process according to any of claims 1 to 4, further characterized in that it comprises the additional step of polymerizing the monomer component in the oil phase of the emulsion removed from the static mixing zone to form a foam material polymeric

7. The process according to claim 5, further characterized in that it comprises the additional step of dehydrating the polymeric foam material to such an extent that a polymeric, crushed foam material is formed, which will be expanded again after contact with fluids. watery

8. The process according to any of claims 5 to 6, further characterized in that: a) the monomer component is capable of forming a polymer having a Tg of about 35 ° C or less, and comprises: i) 50 to 70% by weight of a monomer selected from the group consisting of isodecyl acrylate, n-dodecyl acrylate and 2-ethylhexyl acrylate, and mixtures thereof; ii) from 15 to 30% by weight of the comonomer selected from the group consisting of styrene, ethylstyrene and mixtures thereof; and iii) from 15 to 25% by weight of an entanglement agent selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 2-butenediol dimethacrylate, glycol diacrylate. ethylenic, triacrylate and trimethylol propane trimethacrylate and mixtures thereof; and b) the emulsifier component comprises an emulsifier selected from the group consisting of sorbitan monoesters of branched C 16 -C 24 fatty acids, saturated C 16 -C 22 fatty acids, and saturated linear C 12 -C 24 fatty acids; diglycerol monoesters of branched C16-C24 fatty acids, linear unsaturated C16-C22 fatty acids, and saturated linear C12-C14 fatty acids; monoaliphatic diglycerol ethers of C16-C24 branched alcohols, linear unsaturated C16-C22 alcohols, and saturated linear C12-C14 alcohols; and mixtures thereof.

9. The process according to claim 8 further characterized in that the emulsified contents of the dynamic mixing zone are maintained at a temperature of 5 ° to 95 ° C during step (D).