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`Dispersion Techniques for Carbopol®* Polymers
`
` TECHNICAL DATA SHEET
`TDS-103
`Edition: October 15, 2007
`Previous Edition: January, 2002
`
`
`
`Carbopol® polymers are highly water and polar
`solvent soluble polymers which function as efficient
`thickeners and stabilizers
`for suspensions or
`emulsions. Much of the exceptional utility of the
`Carbopol® polymers results from the hydrophilic
`nature of
`the polymer.
` A single particle of
`Carbopol® polymer will wet out very rapidly when
`put into water. Like many fine particulate powders,
`Carbopol® polymers tend to clump when improperly
`added to the solvent.
`The surface of a powder aggregate solvates to form
`a tough outer layer which prevents complete
`wetting of the interior polymer particles. This
`results in dispersion defects such as grainy texture,
`reduced viscosity or the presence of insoluble
`particles resembling fish eyes.
`reproducible
`To prepare high quality and
`dispersions of Carbopol® polymers, the proper
`dispersing technique must be carefully followed.
`I. Direct Addition of Carbopol® Polymers
`into Water
`The proper method to use when adding Carbopol®
`directly to water depends on the quantity and
`concentration of the dispersion to be prepared.
`A. Small Quantity Batch Dispersions
`Dispersions of several hundred milliliters to several
`gallons with concentrations of up to 1.5 weight
`percent Carbopol® polymer can be practically
`prepared by sifting the dry polymer into rapidly
`agitating water.
`Aqueous surface wetting and dispersion of
`Carbopol® polymer is best achieved with moderate
`rate agitation of approximately 800-1200 rpm.
`Motorized mixers such as
`the Eppenbach,
`Colframo, Arde-Barinco, Janke and Kunkel or
`Lightnin' Mixer with a conventional open-blade
`impeller (pitched marine or saw tooth propeller) are
`
`most appropriate. Extremely high-shear mixers
`such
`as Waring
`blenders
`or
`rotor-stator
`homogenizers should be avoided or carefully
`employed. The mixing intensity generated by this
`type of mixer can shear the opened (hydrated)
`polymers resulting in permanent viscosity loss. In
`some cases, this loss can be as high as 50%.
`Conventional
`impellers,
`such as propellers
`or turbines do not impart excessively high shear
`rates. They can be used to mix mucilages for
`extended periods with virtually no decrease in
`polymer efficiency.
`If
`in-line mixers such as colloid mills or
`homogenizers are used, the Carbopol® polymer
`should be initially wetted-out with moderate rate
`agitation. Therefore, the mixing time using the high
`shear mixers will be minimized. If a homogenizer is
`employed, strive to use the lowest shear rate and
`the shortest mixing time to achieve a homogeneous
`mixture.
`When mixing, submerge the impeller until it is very
`close to the bottom of the vessel and angle the
`mixer to generate a vortex which is one to one-and-
`one half impeller diameters. Slowly sift the polymer
`into the vortex of the agitating liquid (approximately
`1200 rpm). Continue the agitation for about 20
`minutes or until a lump-free dispersion is attained.
`In some cases when a Lightnin' Mixer is employed,
`two
`impellers on a
`common
`shaft are
`recommended. The top impeller rapidly disperses
`the polymer before
`the undesirable, partially-
`hydrated lumps are formed. A sifting device such
`as a coarse sieve or a non-corrosive 20-mesh
`metallic screen should be used to slowly sprinkle
`the Carbopol® polymer into the vortex of the water
`generated by the mixer. The sifting method allows
`the slow, controlled addition of the dry Carbopol®
`polymer, enabling each particle to wet out on the
`water vortex. The sieve or screen permits the
`
`
`Lubrizol Advanced Materials, Inc. / 9911 Brecksville Road, Cleveland, Ohio 44141-3247 / TEL: 800.379.5389 or 216.447.5000Lubrizol Advanced Materials, Inc. / 9911 Brecksville Road, Cleveland, Ohio 44141-3247 / TEL: 800.379.5389 or 216.447.5000
`
`The information contained herein is believed to be The information contained herein is believed to be
`
`Materials, Inc.’s direct control. THE SELLER MAKES NO Materials, Inc.’s direct control. THE SELLER MAKES NO
`
`equipment used commercially equipment used commercially
`
`in processing in processing
`
`these these
`
`reliable, but no reliable, but no
`
`representations, guarantees or representations, guarantees or
`
`WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WARRANTIES, EXPRESS OR IMPLIED, INCLUDING,
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`materials, no warranties or guarantees are made as to materials, no warranties or guarantees are made as to
`
`warranties of any kind are made as to its accuracy, warranties of any kind are made as to its accuracy,
`
`BUT NOT LIMITED TO, THE IMPLIED WARRANTIES BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
`
`the suitability of the suitability of
`
`the products the products
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`for for
`the application the application
`
`suitability for particular applications or the results to be suitability for particular applications or the results to be
`
`OF MERCHANTABILITY AND FITNESS FOR A OF MERCHANTABILITY AND FITNESS FOR A
`
`disclosed. disclosed.
`
` Full-scale Full-scale
`
`testing and end product testing and end product
`
`obtained therefrom. The information is based on obtained therefrom. The information is based on
`
`PARTICULAR PURPOSE. Nothing contained herein is PARTICULAR PURPOSE. Nothing contained herein is
`
`performance are the responsibility of the user. Lubrizol performance are the responsibility of the user. Lubrizol
`
`laboratory work with small-scale equipment and does laboratory work with small-scale equipment and does
`
`to be considered as permission, recommendation, nor to be considered as permission, recommendation, nor
`
`Advanced Materials, Inc. shall not be liable for and the Advanced Materials, Inc. shall not be liable for and the
`
`not necessarily not necessarily
`
`indicate end product performance. indicate end product performance.
`
`as an inducement to practice any patented invention as an inducement to practice any patented invention
`
`customer assumes all risk and liability of any use of customer assumes all risk and liability of any use of
`
`Because of the variations in methods, conditions and Because of the variations in methods, conditions and
`
`without permission of the patent owner. without permission of the patent owner.
`
`handling of any material beyond Lubrizol Advanced handling of any material beyond Lubrizol Advanced
`
`
`
`For further information, please visit www.pharma.lubrizol.comFor further information, please visit www.pharma.lubrizol.com
`Lubrizol Advanced Materials, Inc. is a wholly owned subsidiary of The Lubrizol Corporation
`* Trademark owned by The Lubrizol Corporation
`© Copyright 2007 / The Lubrizol Corporation
`
`
`
`AMN1046
`Amneal v. Almirall, LLC
`IPR2019-00207
`
`1
`
`

`

`
`break-up of any loose polymer or agglomerates due
`to the static charge on the particles. A metallic
`screen decreases the tendency to build more static
`charge on the particles as they are sifted.
`Once all the dry polymer has been introduced,
`continue agitating at the moderate to rapid rate for
`10-15 minutes. Reduce the speed to avoid the
`entrapment of excess air.
`For emulsions, add oils and emulsifiers to form the
`emulsion prior to neutralizing the Carbopol® to build
`emulsion viscosity. Neutralization of Carbopol® is
`accomplished with a suitable alkali or amine base.
`For the order of neutralizer addition in gel products,
`see the Carbopol® Troubleshooting Guide.
`
`1. Cowles Blade—Not recommended due to high shear.
`2. Paddle Blade—Frequently used when blending operations follow
`initial dispersion of Carbopol polymer.
`3. 3-Blade Marine Impeller—Excellent choice for dispersing Carbopol®
`polymer. Impeller of choice when making emulsions.
`4. Foddler Impeller—Poor mixing due to low shear.
`5. Hi-Lift Impeller—High shear: use with caution.
`
`Note: Dispersions of Carbopol® polymers made
`to a precise solids level for analytical viscosity
`testing should follow Lubrizol Standard Testing
`Procedure 430-I, "Brookfield Viscosity (low
`shear)."
`
`2
`
`Selecting Neutralizers for
`High Alcohol Solutions
`• Metallic alkali (NaOH, KOH, etc.) will
`neutralize Carbopol® polymers with less
`than 20% ethanol.
`• Triethanolamine (TEA) will neutralize
`Carbopol® polymers up to 50% ethanol
`solution.
`• 2-Hydroxypropyl ethylene diamine
`(Quadrol®) will neutralize Carbopol®
`polymers up to 70% ethanol solution.
`
`
`B. Large Quantity Batch Dispersions
`Dispersion volumes ranging from tens of gallons to
`hundreds of gallons at concentrations of Carbopol®
`polymers of up to three weight percent may be
`prepared with an eductor or flocculant disperser.
`This technique is a fast, inexpensive means of
`dispersing Carbopol® polymers with
`reduced
`dusting.
`the rate of dispersion
`Figure 1 shows how
`increases with an increase in water pressure.
`Figure 2 shows the basic design of the eductor. It
`is a small, inexpensive, metal or plastic, non-
`moving plumbing valve which exerts a partial
`vacuum on the powder inlet via the Bernoulli effect.
`Carbopol® polymer is pulled from the eductor funnel
`into the eductor valve throat. The partial vacuum is
`created by the flow of incoming make-up water
`through the venturi of the eductor throat. Water
`turbulence within the valve wets out the polymer to
`enable the formation of quality dispersions.
`The eductor outlet should have enough piping (4-5
`ft.) to build sufficient back pressure to direct the
`polymer/ water slurry into an agitated mix tank filled
`with water to complete polymer hydration.
`Eductors can disperse 22.7 kg (50 lb>) of polymer
`in five to ten minutes with up to 3.0% polymer
`concentration. Determining the exact eductor and
`size required for the specific application can best
`be determined from the technical bulletins and
`advice of an eductor manufacturer.
`Note: Select an eductor which is capable of a
`solid particle dispersion. Do not use a liquid
`eductor model. The funnel may be replaced by
`a flexible hose with stainless steel end tube to
`enable direct vacuum pick-up from the box of
`Carbopol® polymer.
`
`2
`
`

`

`3
`
`Further information regarding eductors can be
`obtained from these manufacturers:
`PENBERTHY
`P.O. Box 112
`Prophetstown, IL 61277
`Phone: (815) 537-2311
`FAX: (815) 537-5764
`AMETECK INCORPORATED
`Division of Schutte and Koerting
`2233 State Road
`Bensalem, PA 19020
`Phone: (215) 639-0900
`FAX: (215) 639-1597
`FOX VALVE DEVELOPMENT
`CORPORATION
`Hamilton Business Park, Unit 6A
`Franklin Road
`Dover, NJ 07801
`Phone: (201) 328-1011
`FAX: (201) 328-3651
`DICKENS & WILLIAMSON
`INCORPORATED
`P.O. Box 25009
`Charlotte, NC 28212
`Phone: (704) 537-0304
`FAX: (704) 245-1977
`
`C. Large Quantity Continuous Production
`Dispersions
`The production of good quality, high-solids
`Carbopol® polymer dispersions from a continuous
`production scheme is possible with a mechanical
`in-line powder disperser. Mechanical dispersers
`use the principle of a high velocity eductor coupled
`with the mechanical working configuration of an in-
`line homogenizer to rapidly disperse and wet each
`individual polymer particle instantaneously. This
`highly turbulent, high-shear mixer operates at such
`a rapid rate that the particles are wetted and
`expelled prior to polymer swelling. Lump formation
`and polymer degradation from mechanical shearing
`are eliminated.
`The valved powder hopper feed of the mechanical
`disperser can significantly reduce the level of air
`entrapment or foaming. Dispersed particles are
`expelled from the disperser directly in a tank
`with low/moderate agitation. Table 1 provides
`comparative outline of mechanical dispersers
`and their features.
`
`
`
`Figure 1
`Dispersion Rate of Carbopol® Polymers with an Eductor
`
`Poor dispersing
`below 5 gal/min
`or 35 psig
`
`Recommended
`Operating Area
`
`2
`
`6
`
`10
`
`14
`
`18
`
`22
`
`26
`
`30
`
`Water Flow Through Eductor, gal/min
`
`26
`
`22
`
`18
`
`14
`
`10
`
`6 2
`
`Feed Rate of Carbopol Resins lb/min
`
`
`
`Figure 2
`Eductor
`
`Funnel
`
`Air vent holes
`
`Make-up
`water in
`
`Eductor outlet
`
`
`
`
`
`3
`
`

`

`4
`
`Tips for Using an Eductor
`• Avoid using hot water. The water vapor
`will prematurely swell the polymer end clog
`the eductor.
`• A minimum 3/4-inch (2 cm) diameter pipe
`end 35 psig (1.2 atm) water pressure is
`required for an eductor. Constant pressure
`must be maintained. If necessary, include
`a pump for inlet water.
`• The eductor should be installed with easily
`removable plumbing fittings to facilitate
`cleaning. The discharge must be located
`above the liquid level of the tank to prevent
`back pressure.
`• Prevent plugging of the eductor throat by
`starting with a clean eductor and initiating
`the water flow before adding the
`preweighed polymer to the eductor funnel.
`If the eductor does plug with dry polymer,
`care should be taken when cleaning so that
`the eductor orifice size is not altered.
`• Tapping the funnel manually or with an
`inexpensive vibrator will prevent Carbopol®
`polymer from sticking to the funnel.
`
`
`
`
`
` A
`
` handy technique to break the foam is to partially
`collapse the polymer by the addition of a very low
`level of strong mineral acid. The yield value is
`reduced and the trapped air surfaces. Phosphoric
`or hydrochloric acid is effective at O.5% on the
`weight of Carbopol® polymer. A 1.0 weight percent
`dispersion of Carbopol® polymer would require
`0.005 weight percent or 50 ppm H3PO4 or HC1.
`This
`level of acid
`results
`in no significant
`contribution of salt when neutralizing Carbopol®
`polymer. Therefore, the viscosity of the end
`product is unaffected. Organic acids such as citric
`or lactic acid are not recommended because they
`are weaker acids and would yield higher
`concentrations of residual salts upon neutralization.
`
`
`
`
`
`
`
`
`Further information regarding mechanical disper-
`sers can be obtained
`from
`the
`following
`manufacturers or distributors.
`YTRON®
`Dr. Karg GmbH
`Osternacherstrasse 50
`D-8210 Prien am Chiemsee
`Germany
`Phone: 08051/1457
`QUADRO™ PROCESS INC.
`72 King Street South
`St. Jacobs, ON
`Canada NOB 2N0
`Phone: (519) 664-3724
`SILVERSON MACHINES LTD.
`Waterside Chesham, Bucks
`HP5 1 PQ, England
`United Kingdom
`Phone: 0494786331
`NORTH AMERICAN
`SILVERSON MACHINES LTD.
`P.O. Box 589
`50 Industrial Drive
`East Longmeadow, MA 01028
`Phone: (413) 525-4825
`ARDE BARINCO INC.
`500 Walnut Street
`Norwood, NJ 07648
`Phone: (201) 784-9880
`
`D. Carbopol® Polymers and Foam
`Some foaming can occur in the preparation of
`Carbopol® polymer in water dispersions, particularly
`with Carbopol® 1342 and 1382. The significant
`yield value of
`these dispersions
`(even as
`unneutralized polymers) can result in the formation
`of a persistent foam.
`
`Table 1
`Mechanical Dispersers for Carbopol® Polymers
`Maximum
`Carbopol
`Carbopol
` Polymer
`Polymer
`Capacity
`Solids
`(lbs./hr.)
`(wt. %)
`
`Manufacturer/
`Distributor
`
`Water
`Flow Rate
`(lbs./hr.)
`
`Model
`
`ZC
`
`YTRON
`QUADRO
`Silverson
`Machines Ltd.,
`UK
`Arde Barinco Inc.
`
`1200
`
`15*
`
`15,000
`
`7500
`
`15-20*
`
`50,000
`
`1000
`
`4
`
`Silverson
`Flashblend
`Arde Vaccuum
`30,000
`Dilumelt
`* Dispersions of greater than 5 weight percent Carbopol® polymer become
` dense, solid-like, and impractical to pump or handle.
`
`
`4
`
`

`

`5
`C. Dispersing Carbopol® Polymer in Polar
` Organic Systems
`Since polar organic solvents prevent the rapid
`swelling of Carbopol® polymers, sifting
`the
`polymers may be optional. In pure solvent or at
`the Carbopol®
`high concentrations
`in water,
`polymer can be directly added with minimal
`agitation. When using pure solvent, add the
`polymer/solvent slurry to water, or vice versa, with
`vigorous (800-1200 rpm) mixing. Polar organic
`solvents include alcohols and glycols.
`D. Dry Blending of Carbopol® Polymers
`To reduce addition and mixing time, Carbopol®
`polymers can be initially dry blended with other dry
`ingredients. The blend is usually free-flowing and
`free of lumps if the polymer constitutes less than
`half of the total dry weight. Avoid blending
`Carbopol® polymer with polyvinylpyrrolidone (PVP),
`cellulosic polymers or other gums and clays.
`These blends may give water insoluble complexes
`or may prevent proper swelling of Carbopol®
`polymer.
`the compatibility of Carbopol®
`Note: Test
`polymer in the oil in which it is to be dispersed.
`In the presence of some polar oils (aromatic or
`dicarboxylic acid esters) or molten oils above
`60°C, Carbopol® polymer will physically
`plasticize, hindering stable emulsion formation.
`Dispersing Carbopol® polymer directly into the
`water in these cases will result in smooth,
`stable emulsions.
`
`
`
`II. Indirect Addition of Carbopol® Polymers
`into Water
`In emulsions and alcoholic/water gels, optimum
`dispersions can best be prepared using the indirect
`method of adding Carbopol® polymer
`to a
`formulation. The dispersion preparation can be
`simplified by blending Carbopol® polymer and a
`liquid nonsolvent, such as the oil phase of an
`emulsion, ethanol/isopropanol, or a hydrophobic
`surfactant, to form a premix. Any non-solvent of
`Carbopol® polymer which is part of the product's
`formulation or is an acceptable additive to the
`product may be used. A solid concentration of up
`to 10 weight percent of Carbopol® polymer can
`work.
`A. Oil-in-Water Emulsions
`Combine the ingredients of the oil phase and,
`if required, heat until all materials are liquid.
`Temperature must not exceed 60°C.
` Add
`Carbopol® polymer to the oil phase with moderate
`to vigorous agitation of 600-800 rpm. Immediately
`follow with the addition of water containing the
`appropriate inorganic or amine base to neutralize
`and thicken the Carbopol® polymer and set the
`emulsion. Increase the rate of agitation to 1000-
`1200 rpm and mix for 15-20 minutes or until a
`smooth, non-grainy texture is apparent.
`B. Aqueous Suspension from Insoluble
` Concentrates of Carbopol® Polymers
`Non-solvent dispersions with Carbopol® polymer in
`mineral oil, mineral spirits, kerosene and low HLB
`non-ionic surfactants can be prepared using
`moderate agitation to wet out the polymer prior to
`its addition into water. This bulk dispersion of the
`polymer by a non-solvent delays the rate at which
`the Carbopol® polymer swells or hydrates into
`water, thus minimizing clumping or the formation of
`inferior quality aqueous dispersions.
`These non-solvent dispersions of Carbopol®
`polymers should be used immediately to avoid solid
`polymer settling or agglomeration of the polymer
`due to plasticization.
`
`5
`
`