Polyglycerols General Overview

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1 Polyglycerols are biodegradable products that have been known since the beginning of the 20th century. However, it is only in the last decade that high purity products were developed. This led to their increasing use either as such or in the form of derivatives, mainly polyglycerol esters. Polyglycerol esters are non ionic surfactants that have been used for many years as emulsifiers in food and personal care products. They have been used in Europe and America since the 1940s and were approved for food use in the USA in the 1960s. Due to the innocuous nature of these products, formulators continue to develop technologies that incorporate polyglycerol esters in a widening array of applications. The Solvay Group, with the wealth of more than 30 years of experience in the production of glycerol, has extended its knowledge to the development of a high purity polyglycerol product line consisting of Diglycerol and Polyglycerol-3. These products have been introduced in Europe and in Japan in the early 1990s and are available in the US through Solvay Chemicals, Inc. Solvay Polyglycerols have a high degree of purity, and are of consistent composition. They are from vegetable origin, free from animal sourced materials, and are Kosher and Halal certified. Page 1/10

2 Solvay Diglycerol is a clear, colorless, odorless, water soluble liquid, less volatile and more viscous than glycerol. Being biocompatible, Diglycerol is incorporated in personal care formulations for its mild humectant properties and its ability to enhance fragrance/flavor impact and longevity. It can also be used in industrial applications as a plasticizer in polyvinyl alcohol (PVA) films or starch based biodegradable thermoplastic compositions, or for the manufacture of polyurethanes and polyesters. Alkoxylated diglycerol products were developed for their thickening properties. However, the most popular derivatives of Diglycerol are its esters, used as emulsifiers in food, personal care, and some industrial applications such as antifogging agents in polyolefin and PVC films. High purity Diglycerol also allows the manufacture of distilled monoesters with a high monoester content (min. 80%), similar to distilled monoglycerides. Such esters cannot be obtained from lower purity polyglycerols. Solvay Polyglycerol-3 is a clear yellowish liquid that is more viscous than Diglycerol. Its unique composition vs. traditional condensation polyglycerols imparts many advantages to its fatty acid esters. These include a higher functionality which translates into higher yields during ester production and a superior performance of the esters. Polyglycerol-3 esters may be used in cosmetic, food, and industrial applications. Solvay Polyglycerol-4, the newest addition to our product line, has many of the advantages of Polyglycerol-3 but is more viscous because of its oligomer distribution is centered around tetraglycerol. For more information about the applications of Diglycerol and Polyglycerol-3, and their esters, please refer to our other technical datasheets on the web site posted at the bottom of the page. Manufacturing process Polyglycerols consist of glycerol units linked by an ether linkage. Diglycerol Triglycerol Polyglycerols may widely differ in composition, depending upon their production process. Solvay polyglycerols are produced by the alkaline condensation of glycerol, 1 (vegetable origin). This is followed by hydrolysis, neutralization, and purification of the product. This process is designed to produce high quality products with reduced amounts of cyclic components which have reduced functionality (less hydroxyl groups available). This process also allows an excellent control of the reaction resulting in a narrow oligomer distribution and a minimum batch-to-batch variability. Page 2/10

3 Specifications Content Unit Diglycerol Polyclycerol-3 Polyglycerol-4 Diglycerol % w/w > <10 Triglycerol % w/w Tetraglycerol % w/w Pentaglycerol % w/w < Pentaglycerol and Hexaglycerol % w/w Hexaglycerol and higher oligomers % w/w <5 <10 Heptaglycerol and higher oligomers % w/w <10 Water g/kg <0.5 <1 <1 Chloride mg/kg <50 <100 <100 Color (Hazen Scale) APHA <30 <250 Composition Diglycerol Solvay Diglycerol (INCI diglycerin) is a high purity material, containing a minimum of 90% diglycerol. The remainder of the product is primarily a combination of glycerol and triglycerol. In contrast, many Polyglycerol-2 products of the same average molecular weight contain as much as 40% glycerol. Comparison of the oligomeric distribution of Solvay Diglycerol and a typical Polyglycerol-2 Page 3/10

4 Furthermore, the Solvay manufacturing process leads to a high level of linear α,α -diglycerol and minimizes the generation of cyclic components. The typical composition of Solvay Diglycerol is: α,α -diglycerol (~84%) α,β-diglycerol (~14%) β,β -diglycerol (<1%) Cyclic isomers (<0.2%) include: Page 4/10

5 Polyglycerol-3 Solvay Polyglycerol-3 (INCI polyglycerin-3) is a glycerol oligomer based on an average of three glycerol groups (average MW = 250 g/mol). It typically contains minimum 80% di-, tri- and tetraglycerol. Solvay Polyglycerol-3 also has high levels of linear isomers and low levels of cyclic byproducts compared to the traditional polyglycerols known for many years. Comparison of the oligomeric distribution of Solvay Polyglycerol-3 and a traditional Polyglycerol-3 Physico-chemical properties Solvay polyglycerols are clear transparent liquids that are colorless (Diglycerol) or slightly yellowish (Polyglycerol-3). Solvay Diglycerol Solvay Polyglycerol 3 Page 5/10

6 The following table compares the physico-chemical properties of Solvay Diglycerol and Polyglycerol-3 with glycerol Property Unit Solvay Solvay Glycerol Polyglycerol-3 Diglycerol Density g/ml Dynamic viscosity Pa.s Refractive index Dielectric constant Boiling point C (1.3 mbar) 290 Heat of dissolution in water J/g Specific heat capacity J/g.K Thermal conductivity W/m.K Thermal expansion coefficient C (20-60 C) (20-60 C) (20-25 C) Flash point C Fire point C Autoignition C Results obtained at 25 C, unless otherwise noted. Viscosity The higher viscosity of Solvay Diglycerol and Polyglycerol-3 compared to glycerol provides greater body to personal care formulations. This could lead to a reduction in the amount of thickening agent needed. Dynamic viscosity of Solvay Polyglycerols compared to glycerol Page 6/10

7 Refractive index The higher refractive index of Solvay Polyglycerols compared to glycerol is valuable in formulating transparent emulsions. Refractive index of Solvay Polyglycerols compared to glycerol and cyclic diglycerol Transparent emulsions are obtained when the refractive index of the aqueous and oily phases are similar. 2 The use of higher refractive index ingredients in the aqueous phase, such as Solvay Polyglycerols, facilitates formulation and reduces the need to add other components to increase the refractive index of the aqueous phase. It improves the optical clarity of the formulation and allows the addition of more water, reducing cost. 3,4 Thermal stability The enhanced thermal stability of Solvay Polyglycerols is of particular importance during the manufacture of esters. High reaction temperatures are usually used in ester production, especially in the absence of a catalyst. Thermal stability of Solvay Polyglycerols compared to glycerol and cyclic diglycerol (under air) Page 7/10

8 Weight % Temperature ( C) Thermal stability of Solvay Diglycerol under air and nitrogen Thermal stability of Solvay Polyglycerol-3 under air and nitrogen The same is true for polyglycerol esters, which are known to be generally more stable than their glycerol homologues. Note that the low content of glycerol in both Solvay Diglycerol and Polyglycerol-3 further enhances the thermal stability of their esters compared to traditional polyglycerols. Biodegradability Biodegradability is especially important in our environmentally conscious economy. Solvay Polyglycerols exhibit a high biodegradability, compared to traditional products. This could be explained by their low content of cyclic products. Indeed, cyclic diglycerol was found to degrade more slowly than the linear derivative. Page 8/10

9 The following graph was generated using the Zahn-Wellens Test. Degradation is reported as % COD (Chemical Oxygen Demand). Biodegradability of Solvay Diglycerol and Polyglycerol-3 compared to cyclic diglycerol These results show a total biodegradability of Diglycerol and Polyglycerol-3 (COD>70%). Regulatory status United States Cosmetics Solvay Diglycerol, Polyglycerol-3, and many of their esters can be used in personal care products and are listed in the International Cosmetic Ingredient Dictionary and Handbook. Food Industrial Solvay Polyglycerol-3 and Diglycerol may be used in the production of polyglycerol polyricinoleates (PGPR) for use as emulsifiers in chocolate products. They may also be used in the production of fatty acid ester emulsifiers (PGFA) when the fatty acids are from sources identified in 21 CFR and the Federal Food, Drug, and Cosmetic Act. With the use of appropriate esterification and production processes, the PGFA and PGPR should comply with the Food Chemicals Codex monograph for PGFA and the proposed monograph for PGPR. Diglycerol and Polyglycerol-3 are registered under TSCA. They can be used in industrial applications regulated by the US Environmental Protection Agency (EPA) either as such or for the production of derivatives. Diglycerol and Polyglycerol-3 derivatives can be used in industrial applications governed by the EPA only if they are TSCA registered. Page 9/10

10 PGFA registered under the Toxic Substances Control Act (TSCA) and made from Solvay Diglycerol and Polyglycerol-3 may be incorporated as antifogging agents in polyolefin films complying with FDA regulations set in 21 CFR at a maximum use level of 0.152mg/in 2, or in other films at a maximum use level of 0.14mg/in 2, in accordance with applicable FDA Threshold of Regulation exemptions. European Union Cosmetics Diglycerin, Polyglycerin-3 and many of their esters are mentioned in the annex (section 1) of the Commission Decision 96/335/CE establishing an inventory and a common nomenclature of ingredients employed in cosmetic products. Food Solvay Polyglycerol-3 and Diglycerol comply with EU polyglycerol specifications for use of polyglycerol esters and polyglycerol polyricinoleate in food under EU Commission Directive number 98/86/EC (E 475 and E 476) of November 11, 1998 on food additives other than colors and sweeteners. Esters made from Solvay Polyglycerol-3 and Diglycerol are approved for addition to food-contact materials under EU Directive number 95/3/EC of the European Parliament and Council of Europe of February 23, 1995 on plastic materials and articles intended to come into contact with foodstuffs. Industrial Solvay Diglycerol complies with the listing in EINECS with CASRN , and EINECS number Solvay Polyglycerol-3 is considered a no-longerpolymer (not complying with the definition of a polymer and marketed before 1993, according to EU Directive 92/32/EEC). References 1. US 3,968,169, publ. July 6, 1976, Process for Preparing Polyglycerol. 2. J. Ziming Sun, M.C. Erickson, and J.W. Parr, Refractive Index Matching: Principles and Cosmetic Applications, Cosmetics and Toiletries, 2003, 118(1), R.E. Stier, and J. Lucia, Diglycerol : A Humectant with Unique Sensory Qualities, Cosmetics & Toiletries, 2003, 118(6), US 6,652,842, publ. November 25, 2003, Deodorant Compositions Comprising Diglycerol. Disclaimer To our actual knowledge, the information contained herein is accurate as of the date of this document. However, neither Solvay Chemicals, Inc. nor any of its affiliates makes any warranty, express or implied, or accepts any liability in connection with this information or its use. This information is for use by technically skilled persons at their own discretion and risk and does not relate to the use of this product in combination with any other substance or any other process. This is not a license under any patent or other proprietary right. The user alone must finally determine suitability of any information or material for any contemplated use in compliance with applicable law, the manner of use and whether any patents are infringed. This information gives typical properties only and is not to be used for specification purposes. Solvay Chemicals, Inc. reserves the right to make additions, deletions or modifications to the information at any time without prior notification. Please note that polyglycerol and diglycerol esters are not part of the business of Solvay Chemicals, Inc. and its affiliates, but may be a business of other companies potentially also owning related intellectual property rights. No warranty is made and no liability is taken whatsoever by Solvay Chemicals, Inc. or any of its affiliates with regard to the freedom to use any of the information given herein on polyglycerol and diglycerol esters. Copyright , Solvay Chemicals, Inc. All Rights Reserved Page 10/10 Chemical and Pharmaceutical Group