The Specialty Chemicals Innovator
`
`TDS-237
`Edition: January, 2002
`
`Neutralizing Carbopol® and Pemulen® Polymers in
`Aqueous and Hydroalcoholic Systems
`
`Carbopol® Ultrez™ 10
`
`Carbopol® ETD™ 2020
`
`Carbopol® ETD™ 2050
`
`100,000
`
`10,000
`
`1,000
`
`Brookfield Viscosity, cP, 20 rpm
`
`2
`
`4
`
`6
`
`pH
`
`8
`
`10
`
`12
`
`14
`
`Figure 1
`Carbopol Polymers Viscosity vs. pH (0.5% Concentration)
`
`Effect of pH on Viscosity
`Carbopol polymers must be neutralized in order to
`achieve maximum viscosity. Unneutralized dispersions
`have an approximate pH range of 2.5-3.5 depending
`on the polymer concentration. The unneutralized
`dispersions have very low viscosities, especially
`Carbopol® ETD and Ultrez polymers. Once a
`neutralizer is added to the dispersion, thickening
`gradually occurs as is demonstrated by Figure 1.
`Optimum neutralization is achieved at a pH of
`6.5-7.0, but is not necessary. As demonstrated by
`the graph, high viscosities can be achieved in a
`range of 5.0-9.0.
`A common question is "what pH is correct for my
`finished product?" The answer is that there is no
`correct or incorrect pH. pH should be determined
`by the desired attributes for a given application.
`Viscosity begins to decrease after a pH of 9.0, and
`will continue to decrease if the pH is increased. This
`is due to the dampening of the electrostatic repulsion
`caused by the presence of excess electrolytes. It is
`possible to achieve high viscosity systems at pH
`values below 5 and above 9, but the use level of
`the Carbopol polymer must be increased.
`
`The Specialty Chemicals Innovator
`The information contained herein is believed to be reliable,
` The SELLER MAKES NO WARRANTIES,
`control.
`tions and equipment used commercially in processing
`but no representations, guarantees or warranties of any
`EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED
`these materials, no warranties or guarantees are made as
`kind are made as to its accuracy, suitability for particular
`TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
`to the suitability of the products
`for
`the application
`applications or the results to be obtained therefrom. The
`AND FITNESS FOR A PARTICULAR PURPOSE. Nothing
`disclosed. Full-scale testing and end product performance
`information is based on laboratory work with small-scale
`contained herein
`is
`to be considered as permission,
`are the responsibility of the user. Noveon, Inc. shall not be
`equipment and does not necessarily indicate end product
`recommendation, nor as an inducement to practice any
`liable for and the customer assumes all risk and liability of
`performance. Because of the variations in methods, condi-
`any use or handling of any material beyond Noveon’s direct
`patented invention without permission of the patent owner.
`.
`.
`Noveon, Inc. / 9911 Brecksville Road, Cleveland, Ohio 44141-3247 / TEL: 800-379-5389 or 216-447-5000
` ® Trademark of Noveon, Inc.
` © Copyright 2002 Noveon, Inc.
`
`1
`
`AMN1030
`
`

`

`2
`
`Neutralization
`Ratio Base/
`Carbopol®
`Polymer
`
`2.3/1.0
`
`0.7/1.0
`
`2.7/1.0
`
`4.5/1.0
`
`0.9/1.0
`
`1.5/1.0
`
`3.3/1.0
`
`6.2/1.0
`
`1.2/1.0
`
`1.5/1.0
`
`Figure 2
`Schematic Depicting Molecule of Carbopol Polymer
`in Coiled State
`
`Figure 4
`Neutralization Ratio Chart
`
`Trade Name
`
`CTFA Name
`
`Manufacturer
`
`NaOH (18%)
`
`Ammonia
`(28%)
`
`KOH (18%)
`
`Sodium
`Hydroxide
`Ammonium
`Hydroxide
`Potassium
`Hydroxide
`
`L-Arginine
`
`Arginine
`
`Ajinomoto
`
`OH
`
`C = O
`
`H
`
`O
`
`C = O
`
`OH
`
`C = O
`
`H
`
`O
`
`O = C
`
` OH
`
`O = C
`C O
`
`=
`
`O
`
`H
`
`H
`CO
`O
`
`=
`
`AMP-95®
`
`Neutrol® TE
`
`Aminomethyl
`Propanol
`Tetrahydro-
`xypropyl
`Ethylenediamine
`
`TEA (99%)
`
`Triethanolamine
`
`Angus
`
`BASF
`
`2.3/1.0
`
`Figure 3
`Diagram Depicting Molecule of Carbopol Polymer
`in Uncoiled State
`
` -- +
`O NH4
`
`C = O
`
` C = O
`
`NH4O+ --
`
` C = O
`
`NH4O+ --
`
`Tris Amino®
`(40%)*
`Ethomeen®
`C-25
`Diisopropanol-
`amine
`Triisopropanol-
`amine
`
`Tromethamine
`
`Angus
`
`PEG-15
`Cocamine
`Diisopropanol-
`amine
`Triisopropanol-
`amine
`
`Akzo
`
`Dow
`
`Dow
`
`* NOTE: The 40% solution should be made from Tris Amino crystals from the manufacturer.
`Do not use the pre-dispersed solution from the manufacturer as it contains many impurities.
`
`Thickening Mechanism
`Carbopol polymers as supplied are dry, tightly
`coiled acidic molecules. Once dispersed in water,
`the molecules begin to hydrate and partially uncoil.
`The most common way
`to achieve maximum
`thickening from Carbopol polymers is by converting
`the acidic Carbopol polymer to a salt. This is easily
`achieved by neutralizing the Carbopol polymer with
`a common base such as sodium hydroxide (NaOH)
`or triethanolamine (TEA).
`
`Common Neutralizers
`Figure 4 lists ten of the most common neutralizers
`used, the manufacturers of these neutralizers, and the
`appropriate ratio (as compared to one part of Carbopol
`polymers) to use to achieve exact neutralization at a
`pH of 7.0. The chart is based on Carbopol® Ultrez™
`10, Noveon, Inc.'s newest addition to the Carbopol
`polymer family, but is applicable to all Carbopol
`polymers because they all have the same equivalent
`weight of 76 ± 4.
`
`2
`
`

`

`3
`
`Hydroalcoholic Thickening
`Ethanol and isopropanol can be thickened with
`Carbopol® polymers. The critical factor is choosing
`the correct neutralizer based on the amount of alcohol
`that is to be gelled. If the wrong neutralizer is used,
`the salt of the Carbopol polymer will precipitate out
`because it is no longer soluble in the hydroalcoholic
`blend. Figure 5 gives recommended neutralizers for
`various alcohol levels.
`
`Figure 5
`Recommended Neutralizers for Hydroalcoholic Systems
`
`Up to % Alcohol
`
`Neutralizer
`
`20%
`
`30%
`
`60%
`
`60%
`
`80%
`
`90%
`
`90%
`
`90%
`
`Sodium Hydroxide
`
`Potassium Hydroxide
`
`Triethanolamine
`
`Tris Amino
`
`AMP-95®
`
`Neutrol TE
`
`Diisopropanolamine
`
`Triisopropanolamine
`
`>90%
`
`Ethomeen C-25
`
`3
`
`