Next-generation Carbopol® Polymer Proves Highly Efficient at Lower pH Levels

Apr 19, 2013 | Contact Author | By: Bryan Moran, Sr. Personal Care R&D Scientist, Lubrizol Advanced Materials, Inc.
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Title: Next-generation Carbopol® Polymer Proves Highly Efficient at Lower pH Levels
carbomerx rheology modifierx viscosityx suspensionx stabilityx AHAsx BHAsx
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Consumer demand for products that provide anti-aging and healthy-skin benefits is driving the creation of many new cosmetics. However, many of the active ingredients that are beneficial to the face and neck are most effective at lower pH ranges. In this Q&A, Lubrizol’s Bryan Moran, Sr. R&D Scientist, talks about Carbopol® Ultrez 30 polymer (INCI: Carbomer), a new rheology modifier, and how it can help formulators achieve preferred viscosity, suspension and stability in gels or emulsions containing challenging additives such as alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs).

Q: Has there been a demonstrated need for a next-generation carbomer?

A: Lubrizol works closely with formulators and marketers on a regular basis. And we know they’ve long been interested in being able to formulate at a lower pH—under 5.0, a level that will allow them to deliver on claims by using the acid-active ingredients and alternative preservatives that are preferred by consumers. We also know the capabilities of the currently available acrylate-based polymers—and what’s missing from them. Lubrizol developed technologies like Carbopol Aqua SF-2 polymer for low pH surfactant systems, but there still exists a gap in systems for leave-on skin care.

Q: What is the issue with existing acrylate-based rheology modifiers and carbomers in leave-on skin care?

A: When claims-driving acidic or electrolytic actives are used in formulations, they often have a detrimental effect on the efficiency of existing acrylate-based rheology modifiers. However, in order to deliver maximum benefit to the consumer, a formulation must maintain the appropriate levels of these acid-active ingredients, and must be formulated at a pH below 5.0. With the new Carbopol Ultrez 30 polymer, formulators can now create leave-on skin care products with effective levels of acidic-active ingredients that also have the pleasant sensory attributes, satisfying rheological properties, and stability that consumers demand.

Q: How is this next-generation carbomer different?

A: It is well-understood that the performance of Carbopol polymers can be influenced by subtle variations in the level of cross-linker, distance between cross-links, uniformity of cross-linking, degree of branching and the particle size. By understanding these drivers for performance attributes, Lubrizol has been able to modify the polymer and create this next-generation Carbopol Ultrez 30 polymer. This polymer is able to tolerate low levels of AHAs—such as those systems for daily facial care where 1% to 3% AHA are recommended—and BHAs, and other additives in the formula better than other carbomers have in the past. So it is enabling formulators to develop gels and lotions at low pH levels that still maintain the high efficiency, pleasant sensory properties, desirable flow characteristics, and stability required by the marketplace.

Q: But formulators already had ways to provide thickening at lower pH levels.

A: We know that formulators want to produce a cosmetic that does what it’s expected to do and feels good on the skin so consumers will keep using it long enough for the active to take effect. Formulators find some success with nonionic polymers or naturally sourced gums like cellulose and xanthan, clays and starches to help provide viscosity and stabilization at low pH. But the issue is that these ingredients on their own provide poor aesthetic properties and poor flow properties like stringiness and tackiness that are not desired by consumers. The synthetic thickeners, particularly carbomers, tend to give you better clarity, yield, stability, flow properties and aesthetics, but may not work across a broad pH range. Our new Carbopol Ultrez 30 polymer works synergistically with the natural gums at a low and high pH, while still having the carbomer INCI name.

Q: Specifically, how is Carbopol Ultrez 30 polymer different?

A: It’s a cross-linked homopolymer of acrylic acid, effective in a broad pH range, offering improved electrolyte efficiency and different sensory properties than traditional polymers of a similar composition. To further highlight the efficiency of this next-generation carbomer, the viscosity was evaluated at 0.5 wt% polymer-use levels as a function of pH from 3.5 to 5.0. Measurements were made with a Brookfield® RVT or DV-II at 20 rpm and at 25°C. Click on the link to Figure 1 for test results.

Q: Has your testing uncovered any formulating issues?

A: The relative tolerance to shear versus some other Carbopol polymers is low. This is a common characteristic of other Carbopol polymers such as Carbopol ETD 2050 or 981 polymers, which are generally more sensitive than Carbopol Ultrez 10 or 980 polymers. While we don’t recommend homogenization, in cases where the formulation may require it, such as an emulsion, we recommend doing so before neutralization at the lowest shear rate and for the shortest length of time possible. It is also important to note that sensitivity against shear is equipment-dependent and can be counteracted by process changes such as post-addition of a dispersion of 3% Carbopol Ultrez 30 polymer in deionized water after homogenization.

Q: Any final thoughts?

A: In essence, those who choose to formulate with Carbopol Ultrez 30 polymer have the best of both worlds: an existing INCI name yet a brand-new product with enhanced performance attributes. Because this is a carbomer, formulators and marketers are not being asked to use a new ingredient that is unfamiliar to the marketplace or not approved in some part of the world. We have many customers already using carbomers such as Carbopol Ultrez 10 or Carbopol 980 polymers in their production or in their formulations, but Carbopol Ultrez 30 polymer has new benefits and properties such as viscosity at a low pH and an improved electrolyte tolerance. This polymer disperses quickly, so production can go more quickly and, as a result of reduced mixing times, will incorporate fewer air bubbles and possibly even save time and money. By the way, it even performs well at higher pH levels—up to 12.

Q: What should someone do if he or she is interested?

A: For product details, more information, samples and starting formulations visit www.lubrizol.com/ultrez30 or www.facebook.com/LubrizolPersonalCareTrends, or follow us on Twitter at: https://twitter.com/LZPersonalCare.


TRADEMARKS:
Brookfield is a registered trademark of Brookfield Engineering Laboratories, Inc.
Carbopol is a registered trademark of The Lubrizol Corporation.

DISCLAIMER:
The information contained herein is being furnished for informational purposes only, upon the express condition that the User makes its own assessment of the appropriate use of such information. While the information contained herein is believed to be reliable, no representations, guarantees or warranties of any kind are made as to its accuracy, suitability for a particular application or the results to be obtained herefrom. Lubrizol Advanced Materials, Inc. ("Lubrizol") cannot guarantee how any products associated with this information will perform in combination with other substances or in User’s process. Due to the variations in methods, conditions and equipment used commercially in processing these materials, no warranties or guarantees are made as to the suitability of the information/products for the applications disclosed. Lubrizol shall not be liable and the User assumes all risk and responsibility for, any use or handling of any material beyond Lubrizol's direct control. LUBRIZOL MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. It is the User’s sole responsibility to determine if there are any issues relating to patent infringement of any component or combination of components relating to the supplied information. Nothing contained herein is to be considered as permission, recommendation, nor as an inducement to practice any patented invention without the permission of the patent owner.

 

 

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Figure 1. Viscosity vs. pH of different polymer levels

Figure 1. The viscosity vs. pH of different polymers shows the high thickening efficiency of Carbopol® Ultrez 30 polymer

The Carbopol® Ultrez 30 polymer shows high thickening efficiency, building viscosity after pH 3.5 and reaching a plateau around pH 4.0. By offering maximum and consistent viscosity above pH 4.0, Carbopol Ultrez 30 polymer gives formulators more control over processing in production and facilitating viscosity adjustments.

 

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