Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/32—Polymerisation in water-in-oil emulsions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/40—Mixing liquids with liquids; Emulsifying
  • B01F23/41—Emulsifying
  • B01F23/4105—Methods of emulsifying
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/40—Mixing liquids with liquids; Emulsifying
  • B01F23/41—Emulsifying
  • B01F23/414—Emulsifying characterised by the internal structure of the emulsion
  • B01F23/4141—High internal phase ratio [HIPR] emulsions, e.g. having high percentage of internal phase, e.g. higher than 60-90 % of water in oil [W/O]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/40—Mixing liquids with liquids; Emulsifying
  • B01F23/49—Mixing systems, i.e. flow charts or diagrams
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
  • C10L1/328—Oil emulsions containing water or any other hydrophilic phase
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions

Definitions

• the oil phase can be then be polymerized forming a cellular structure (i.e. a foam) having a cell size distribution defined by the size distribution of the dispersed, internal-phase droplets. Since the cell size distribution has a substantial effect on the properties of the foam, it is advantageous to be able to closely control the droplet size of the internal, dispersed phase in a HIPE being produced for that purpose.
• a cellular structure i.e. a foam
• a method of mixing two or more immiscible fluids to form high internal phase emulsions comprising the steps of: a) providing a first phase; b) providing a second phase, wherein said second phase is substantially immiscible with said first phase and the ratio of said first phase to said second phase is between about 2:1 and about 250:1 ; c) combining said first and second phases to provide a premixed process stream; ) processing said premixed process stream using at least one static mixer segment in a single pass so as to provide sufficient shear to emulsify said first phase in said second phase creating said high internal phase emulsion having a internal phase size distribution with a mean particle size.
• 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 to be made of the HIPE, and the particular properties desired for the HIPE.
• the ratio of water-to-oil phase in the HIPE is at least about 2:1, and is typically in the range of from about 2: 1 to about 250:1, more typically from about 4:1 to about 250:1, even more typically from about 12:1 to about 200:1, and most typically from about 12:1 to about 150:1.
• the relative amounts of the water and oil phases used to form the HIPE are, among many other parameters, important in determining the structural, mechanical and performance properties of the resulting HIPE foams.
• the ratio of water to oil phase in the HIPE can influence the density, cell size, and capillarity of the foam, as well as the dimensions of the struts that form the foam.
• HIPEs according to the present invention used to prepare these foams will generally have water-to-oil phase ratios in the range of from about 12:1 to about 250:1, preferably from about 12:1 to about 200:1, most preferably from about 12: 1 to about 150: 1.
• the oil phase of the HIPE can comprise a variety of oily materials.
• the particular oily materials selected will frequently depend upon the particular use to be made of the HIPE.
• oily is meant a material, solid or liquid, but preferably liquid at room temperature that broadly meets the following requirements: (1) is sparingly soluble (or insoluble) in water; (2) has a low surface tension; and (3) possesses a characteristic greasy feel to the touch. Additionally, for those situations where the HIPE is to be used in the food, drug, or cosmetic area, the oily material should be cosmetically and pharmaceutically acceptable.
• Monomers of this type include, for example, monoenes such as the (C 4 - C )4 ) alkyl acrylates such as butyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl (lauryl) acrylate, isodecyl acrylate tetradecyl acrylate, aryl acrylates and alkaryl acrylates such as benzyl acrylate, nonylphenyl acrylate, the (C 6 -C 16 ) alkyl methacrylates such as hexyl acrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, isodecy
• the monomer will generally comprise 30 to about 85%, more preferably from about 50 to about 70%, by weight of the monomer component.
• These comonomers can comprise up to about 40% of the monomer component and will normally comprise from about 5 to about 40%, preferably from about 10 to about 35%, most preferably from about 15 about 30%, by weight of the monomer component. In one embodiment of the present invention these comonomers are capable of imparting toughness about equivalent to that provided by styrene.
• the 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.
• Divinyl benzene is typically available as a mixture with ethyl styrene in proportions of about 55:45. These proportions can be modified so as to enrich the oil phase with one or the other component.
• sorbitan esters such as sorbitan laurates (e.g., SPAN ® 20), sorbitan palmitates (e.g., SPAN ® 40), sorbitan stearates (e.g., SPAN ® 60 and SPAN ® 65), sorbitan monooleates (e.g., SPAN ® 80), sorbitan trioleates (e.g., SPAN ® 85), sorbitan sesquioleates (e.g., EMSORB ® 2502), and sorbitan isostearates (e.g., CRILL ® 6); polyglycerol esters and ethers (e.g., TRIODAN ® 20); polyoxyethylene fatty acids, esters and ethers such as polyoxyethylene (2) oleyl ethers, polyethoxylated oleyl alcohols (e.g.
• sorbitan esters such as sorbitan laurates (e.g., SPAN ®
• emulsifiers include sorbitan monolaurate (e.g., SPAN ® 20, preferably greater than about 40%, more preferably greater than about 50%), most preferably greater than about 70% sorbitan monolaurate), sorbitan monooleate
• the oil phase will generally comprise from about 65 to about 98% by weight monomer component and from about 2 to about 35% by weight emulsifier component.
• the oil phase will comprise from about 80 to about 97% by weight monomer component and from about 3 to about 20% by weight emulsifier component. More preferably, the oil phase will comprise from about 90 to about 97% by weight monomer component and from about 3 to about 10% by weight emulsifier component.
• the oil phase of these preferred HIPEs can contain other optional components.
• One such optional component is an oil soluble polymerization initiator of the general type well known to those skilled in the art, such as described in US Patent 5,290,820 (Bass et al.), issued Mar. 1, 1994, which is incorporated by reference.
• Another possible optional component is a substantially water insoluble solvent for the monomer and emulsifier components. Use of such a solvent is not preferred, but if employed will generally comprise no more than about 10% by weight of the oil phase.
• a polymerization initiator is typically included in the HIPE.
• Such an 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 foregoing peroxygen compounds with reducing agents such as sodium bisulfite, L-ascorbic acid or ferrous salts.
• the initiator can be present at up to about 20 mole percent based on the total moles of polymerizable monomers in the oil phase. Preferably, the initiator is present in an amount of from about 0.001 to 10 mole percent based on the total moles of polymerizable monomers in the oil phase.
• the two fluids could consist of a dispersed gas and a liquid which by virtue of the stability provided by very small, uniform cell sizes can be used to uniformly contact relatively large surfaces with a relatively small amount of an active carried in the continuous, external phase.
• the dispersed liquid can contain an active ingredient that is soluble (or insoluble) which, upon the polymerization of the continuous (external) phase and evaporation of the dispersed (internal) phase, coats (or is contained in) the polymerized cells for form a polymer foam with various properties.
• rotating elements such as blades, pins, paddles, and the like do not have a uniform tangential speed. Consequently, when a fluid, flowing in the direction of an axis, encounters an element rotating in a plane at an angle to the axis, (typically the plane is the 90 degree cross section) more shear will be imparted at the radial extreme of the element than at the center of rotation.
• This difference in applied shear makes preparation of uniform HIPEs problematic because more shear than optimal may be imparted at the outer radius while less than optimal may be imparted near the center of rotation. Further, the differences in applied shear have differing impacts depending on the size of the rotating element making scale- up difficult.
• static elements that are placed in a viscous, laminar flow, will impart a relatively uniform shear along their length to the extent permitted by the velocity cross section.
• static mixer fluids in a conduit flow along stationary elements with a vector component in the same direction as the flow. Consequently, the relative velocities of the fluid and the mixing elements can be relatively constant across the cross section of the flow. Because such relative velocities are relatively constant, in-line mixers using static elements can be predictably sized according to production needs.
• a "static mixer” or "in-line mixer” is an assembly of one or more segments that mixes or blends a material flowing through a flow conduit by subdividing and recombining the flow.
• a “segment” is an assembly of “elements” that is inserted in the flow conduit.
• An “element” is a portion of a segment that divides the material flowing through the flow conduit into at least two streams that are combined with separate streams provided by other elements of the segment downstream thereof so as to mix the streams.
• the water phase is pressurized by water phase supply pump 15 and the oil phase is pressurized by oil phase supply pump 20.
• flow meters 25 (water phase) and 30 (oil phase) are used to control the amount of each phase delivered to the system by pumps 15 and 20. Because flow control is desirable, positive displacement pumps (progressive cavity, gear, lobe or the like) having delivery characteristics that are relatively independent of back pressure are particularly suitable.
• heat exchangers 35 (water phase) and 40 (oil phase) may be provided to heat the phases to a desired processing temperature.
• the known heat exchange capabilities of static mixers may be used to heat the phases while they are mixing (see discussion below).
• static mixers 55 and 60 could be provided with heat exchange capability for such a task.
• the oil phase comprises polymerizable monomers
• heat exchange capability could be used to heat the process stream to a suitable polymerization temperature.
• Such temperatures are suitably at least about 45 °C, typically at least about 55 °C, and more typically at least about 65 °C.
• While the method of the present invention will produce HIPEs when static mixer 55 has a horizontal orientation it has been found that an orientation having an angle with respect to the horizontal is desirable so that the flow through static mixer 55 has a vertical component.
• the flow axis of the premixed stream has a vertical orientation when it goes through static mixer 55.
• Such vertical orientation is desirable in order to help compensate for potential density differences between the water phase and the oil phase.
• such vertical orientation will help the flow of the premixed stream resist settling of the denser phase and help maintain a more uniform distribution of phases as the premixed stream enters static mixer 55 while the stream viscosity is low (see discussion above) and emulsification has not yet provided resistance to phase settling.
• a vertical orientation also allows for separation of entrained gasses which may, for example, interfere with polymerization reactions for HIPEs comprising a polymerizable monomer.
• a recirculation loop can be provided whereby a portion of the HIPE produced by static mixer 55 is recirculated through static mixer 60.
• Such recirculation can be useful as a means of controlling the amount of shear provided by static mixer 60.
• flow velocity through static mixer 60 (hence shear rate therein) is substantially controlled by the velocity through the recirculation loop (given a specific mixer configuration). That is, the flow rate through the static mixer 60 is determined by a recirculation pump (not shown in Figure 1) rather than water supply pump 15 and oil phase supply pump 20 while finished HIPE flow is determined by the amount of water phase and oil phase delivered to the recirculation loop by water supply pump 15 and oil phase supply pump 20.
• HIPE components can be blended into the process stream and incorporated into the emulsion in multiple stages.
• a particularly useful application of this aspect of the invention is to incorporate a polymerization initiator into an already-formed water in oil HIPE where the oil phase comprises a polymerizable monomer.
• a process stream comprising an aqueous solution of a water soluble initiator, such as potassium persulfate, could be injected into the process stream between static mixer 55 and static mixer 60 (not shown in Figure 1) so that static mixer 60 could disperse the initiator solution throughout the HIPE.
• a water soluble initiator such as potassium persulfate
• conduit diameter may be varied in order to vary flow rate locally within the conduit relative to the mixing element.
• Such cross-sectional variability along the axis can be used to increase shear (smaller cross section), decrease shear (increased cross section), or cycle shear rates (repeated increasing and decreasing cross section) along the length of the mixer.
• such variation can be provided by providing a conduit wherein conduit cross sectional dimensions vary as a function of conduit length.
• static mixers from Sulzer Chemtech having one or more segments wherein each segment comprises an assembly of bar-like elements oriented at a predetermined angle to a flow axis have been found to be suitable.
• suitable static mixers include those available from Charles Ross and Son Company (as a Model ISG), Komax Systems Inc. as a Komax Motionless Mixer), Koch-Glitsch Inc. (such as a Melt Blender, Model SMX, or a Model SMV).
• the static mixer of the present invention may be provided by forming a conduit having segments of increasing element count, angle, and decreasing width (e. g. by increased bar count) to effect greater shear along the axis of the mixing conduit.
• the element count (and angle) and size may be ordered by increasing the individual element bar count with bars of decreasing width and length placed at an increased angle to the axis along the conduit to provide a continuous increase in shear.
• individual element bar segments in individual conduit segments may be connected end to end so that each segment may be rotated relative to the other so as to provide a static mixer with adjustable shear along its length by virtue of being able to adjust each segment relative to the other so as to provide adjustable rotationally oriented shear in the transition from one conduit segment to the others.
• the ends of each segment may be further connected with threaded fittings with 0-ring seals so as to allow for adjustment of axial separation between elements bars in each segment as well as rotational orientation.
• shear rates can be adjusted to vary over time (and length) the uniform droplet size being produced or the uniformity of the droplet size.
• localized (internal) re-circulating flow can be designed into the mixer via the use of curved mixing elements which impart flow counter to the mainstream.
• segmented static mixer thanks to the "plug flow” behavior of static mixers (absence of tails and segregated fluids being pumped through such mixers), they can be used as process components where the HIPE is further processed.
• further processing include injection molding, casting, extrusion, and similar applications, where clean and quick changeovers among different formulations and/or start/stop procedures are required and where changes are needed to the mixing characteristics due to the change in formulation.
• multiple static mixers may be ordered in parallel (including an annular configuration) to provide for ordered structures in the resulting HIPE.
• two static mixers designed to provide different amounts of shear so as to provide a first HIPE having differing droplet sizes can provide HIPEs with a relatively large open cell structure formed continuously in a predetermined relationship with a second HIPE having a relatively small open cell structure.
• Such HIPEs can be then polymerized to provide HIPE-derived foams having a similar relationship in cell sizes so as to provide for acquiring and distributing fluids (through large open cell structures) and for storing fluids (comprised of smaller open-celled structures). Examples of such heterogeneous foam structures are described in US Patent 5,817,704, issued to Shiveley, et al. on October ⁇ , 1998.
• A is a constant that varies from 0 to 1 , depending on the mixer geometry. For example, for the aforementioned SMX mixer A is approximately 1.
• Q is the volumetric flow rate (units of m 3 /s).
• Table 1 lists active surface (Es), diameter, and volumetric flow rate for different SMX mixers that have successfully produced coarse HIPEs. As can be seen, the Es/Q ratio is substantially constant, within an experimental error of 1.05 * 10 +2 +/- 15%.
• Pre-made water (heated up) and oil (room temperature) phases are pumped separately under pressure to a static mixer injection point.
• the injector is configured with the oil injected at the center of the pipe (water flowing annularly therearound) through an orifice (restricted open section), of a diameter equal to 1/10 of the static mixer diameter and away from the first static mixing element not more than approximately 1 mixer diameter length.
• the injected liquids are passed through (1 or more) static mixer segments in a series.
• the mixer axis is vertically oriented with the flow being upward.
• Table 6 shows the effect of applied shear rate in a second mixer on particle size for a coarse HIPE that was formed in a first mixer.
• Droplet size may be measured using light microscopy and/or scanning electron microscopy using techniques as are known to the art as suitable for the composition of the HIPE.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Polymerisation Methods In General (AREA)

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• 2000
  • 2000-10-04 EP EP00968653A patent/EP1222213A1/en not_active Withdrawn
  • 2000-10-04 WO PCT/US2000/027328 patent/WO2001027165A1/en not_active Ceased
  • 2000-10-04 CA CA002386654A patent/CA2386654A1/en not_active Abandoned
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