WO2025038499A1 - Synergistic combination of polysaccharide-based surfactants and internal olefin sulfonate surfactants - Google Patents

Abstract

Surfactant blends are disclosed which exhibit improved stability over a wide pH range. The surfactant blends include a polysaccharide-based surfactant and an internal olefin sulfonate surfactant. Methods of making and using the surfactant blends are further provided.

Description

SYNERGISTIC COMBINATION OF POLYSACCHARIDE-BASED SURFACTANTS AND INTERNAL OLEFIN SULFONATE SURFACTANTS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the priority benefit of U.S. Provisional Patent Application Serial No.63/532,182, filed August 11, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety. TECHNICAL FIELD [0002] The present disclosure generally relates to surfactant blends including polysaccharide- based surfactants and internal olefin sulfonate surfactants. The surfactant blends exhibit enhanced stability and reduced viscosity. BACKGROUND [0003] Surfactant blends are compositions formed of a plurality of surfactants. Surfactants and surfactant blends are important components in many formulations acting as a detergent, cleaning agent, wetting agent, emulsifier, foaming agent, or dispersant in numerous products including household, industrial, and institutional products, personal and home care compositions, and various industrial processes such as oil field and oil production processes. The properties of the surfactant or surfactant blend are important in determining the specific use cases. BRIEF DESCRIPTION OF THE DRAWINGS [0004] FIG.1 depicts a reaction scheme to form internal olefin sulfonate surfactants. [0005] FIG.2 depicts a photograph of a polysaccharide surfactant at various pH conditions. [0006] FIG. 3 depicts a photograph of a second polysaccharides surfactant at various pH conditions. [0007] FIG.4 depicts a photograph of Comparative Example 1 and Inventive Example 2. [0008] FIG.5 depicts a photograph of Comparative Example 2 and Inventive Example 7. DETAILED DESCRIPTION [0009] The present application describes novel surfactant blends which exhibit unexpected stability over a wide pH range and which are biologically-derived and environmentally friendly. Generally, the surfactant blends described herein can include at least a polysaccharide-based surfactant and an internal olefin sulfonate surfactant. The polysaccharide-based surfactant can include a dextrin or dextran compound such as maltodextrin. The surfactant blends can exhibit greater stability than any of the individual surfactants alone as well as reduced viscosity. As used herein, stability refers to the surfactant blend maintaining a stable clear aqueous solution over a pH range of about 3 to about 11 including a pH range of about 5 to about 11 and a temperature range varying from about 0°C to about 60°C including a temperature range of about 23 °C to about 50 °C in various embodiments. [0010] As can be appreciated, polysaccharide-based surfactants can exhibit or suffer various problems when combined with other surfactants or solvents. For example, compositions including polysaccharide-based surfactants can exhibit miscibility, compatibility, and solubility issues as evidenced by the formation of biphasic aqueous solutions when combined with other surfactants or even alone. As can be appreciated, clear aqueous solutions are a sign of stability and are particularly preferred for applications such as personal and home care products where consumers desire clear products as opposed to translucent or opaque products. [0011] Without being bound by theory, it is believed that the surfactant blends described herein exhibit unexpected stability due to one or more of compatibilization between the component surfactants and shielding interactions between the surfactants. [0012] Compatibilization is an interfacial phenomenon observed in heterogeneous solutions or blends. Specifically, compatibilization is a process by which blend properties are enhanced due to increased interaction between the phases which reduces the interfacial tension and stabilizes the mixture. Compatibilization is an effective way to adjust the properties and to manipulate the morphology of immiscible components. [0013] For the disclosed surfactant blends, compatibilization is believed to occur due to interactions with the saccharide head groups of the polysaccharide-based surfactants which can interact with all of the surfactants in the blend. Compatibilization may also be due to resultant micelles that are more efficiently stabilized by the mixed polysaccharide surfactants versus micelles made from conventional surfactants. It is known by those skilled in the art, that mixtures of surfactants can yield synergistic properties that arise from modifying the micellular structure. Mixtures of surfactants can yield a different packing of the surfactants at the micelle interface which results in different micellular structures and physical properties as compared to the same system employing only one type of conventional surfactant. [0014] In addition to compatibilization, it is theorized that shielding can also enhance the compatibility of the polysaccharide-based surfactants through combination with the internal olefin sulfonate surfactants. As can be appreciated, surfactants can interact through various nonbonding interactions such as dipole–dipole interactions and hydrogen bonding. These nonbonding interactions can be especially susceptible to solution ionic strength and pH. Polysaccharide-based surfactants (with multiple groups capable of dipole interactions and hydrogen bonding) have more potential than traditional surfactants (typically with only one, or few groups, capable of dipole interactions or hydrogen bonding) to be affected by ionic strength and pH due to the larger numbers of groups present for dipole and hydrogen bond formation. [0015] The synergistic interaction between the different polysaccharide head groups of the various saccharide-based surfactants is believed to be caused by the polar groups that can interact with the similar groups on different saccharide surfactants as well as the internal olefin sulfonate surfactants. This interaction is believed to prevent, preclude, or lessen the propensity for the saccharide head groups from interacting with the ionic species in the solution thus increasing stability, clarity, and performance. As surfactants interact through nonbonding interactions such as dipole-dipole interactions and hydrogen bonding, polysaccharide-based surfactants can have greater mutual miscibility than traditional surfactants due to the larger number of groups available for dipole and hydrogen bonding. The properties of the surfactant blends described herein can show a synergistic improvement over the properties of the component surfactants which are not stable at pHs lower than about pH 1 and greater than about pH 12. The surfactant blends described herein can also exhibit lower viscosity than either the polysaccharide surfactants or the internal olefin sulfonate surfactants alone. [0016] The surfactant blends described herein exhibit unexpected pH and hydrolytic stability. Specifically, low rates of hydrolysis were observed at both low and high pH with the blends maintaining a clear aqueous solution. The individual surfactants alone did not exhibit such pH and hydrolytic stability as they were observed to separate into distinct immiscible layers and/ or yield a hazy or cloudy aqueous solution that was unstable at both low and high pH. Although the polysaccharide-based surfactants with HLB lower than about 19 are only marginally water soluble and exhibit non-homogenous bilayers or cloudy aqueous solutions, the surfactant blends described herein exhibit a clear aqueous homogenous solution when blended with water at various pH values demonstrating the stability of the blends. As can be appreciated, clarity is vital for both critical to operation of certain compositions and highly desirable for personal and home care compositions. [0017] In certain embodiments, suitable polysaccharide-based surfactants can vary in form. For example, suitable polysaccharide-based surfactants can include surfactants formed of various pyranose-type polysaccharides and furanose-based polysaccharides including α-and β-D- Galactopyranosyl (α,βGalp), 3,6-Anhydro α-D-Galactopyranosyl (αGalp3,6AN), β-D- Mannopyranosyl (βManp), β-D-Mannopyranosyluronic acid (βManpA), α-D- Galctopyranosyluronic acid (αGalpA), β-D-Glucopyranosyluronic acid (βGlcpA), α-L- Glucopyranosyluronic acid (αLGulpA), α-L-Rhamnopyranosyl (αLRhap), β-D-Xylopyranosyl (βXylp), and α-L-Arabinofuranosyl (αLAraf) in various embodiments. [0018] Examples of suitable polysaccharides rings that can be used to form polysaccharide-based surfactants can include:

α- and opyranosyl , p, α-D- acid

β- acid

α-L-

yl [0019] In certain embodiments, the polysaccharide-based surfactant can comprise dextran, dextrin or related compounds. For example, in certain embodiments, the polysaccharide-based surfactant can be a maltodextrin surfactant. In certain such embodiments, the maltodextrin surfactant can have a dextrose equivalent of between about 2 to about 25 including values between about 3 and about 25 such as about 4.5 to about 6.0, or about 9.0 to about 12.0. At least a portion of the sugar monomers may form a reaction product upon being contacted under suitable conditions with a fatty acid salt, such as a salt of a C4-C30 fatty acid or a C4-C20 fatty acid. Without being limited by theory, at least a portion of the sugar monomers may react to form a fatty ester of the polysaccharide compound in some embodiments, optionally present in combination with unreacted fatty acid salt in an aqueous phase. When formed, an ester reaction product may form at any hydroxyl group of the dextrin compound, including any combination of primary and/or secondary hydroxyl groups. [0020] In certain embodiments, suitable polysaccharide-based surfactants can be commercially obtained. For example, suitable polysaccharide-based surfactants can include Tegrasurf® 70, Tegrasurf® 90, Tegrasurf® 120, Tegrasurf® 126, Tegrasurf® 160, Tegrasurf® 166, Tegrasurf® 190, and Tegrasurf® 196 each available from Integrity Bio-Chemicals, LLC (Cresson, TX). In certain embodiments, the polysaccharide-based surfactants can be formed from natural products and can include a blend of surfactants each derived from different sugars. [0021] In certain embodiments, suitable polysaccharide-based surfactants can alternatively be alkylpolyglycoside surfactants. [0022] Suitable internal olefin sulfonate surfactants are alkene or hydroxyalkane compounds which include one or more sulfonate groups. Examples of internal olefin sulfonates and reaction schemes are depicted in FIG.1 which shows the synthesis of hydroxy alkane sulfonates and alkene sulfonates. As can be appreciated, internal olefin sulfonates (IOS) are generally prepared from an internal olefin by sulfonation. IOS compounds can be identified by their carbon number and/or degree of branching. Branched IOS molecules are IOS molecules derived from internal olefin molecules which comprise one or more branches. Linear IOS molecules are IOS molecules derived from internal olefin molecules which are linear and comprise no branches (unbranched internal olefin molecules). [0023] Internal olefins suitable to be formed into internal olefin sulfonates can be formed from either natural or petroleum/synthetic sources and can further include a mixture of linear internal olefin molecules and branched internal olefin molecules. As can be appreciated, an internal olefin sulfonate or internal olefin sulfonate surfactant can be characterized by its carbon number and/or linearity. For internal olefin sulfonates having an average carbon number, this means that the internal olefin sulfonate is a mixture of molecules which differ from each other in terms of carbon number. As used herein, said average carbon number is determined by multiplying the number of carbon atoms of each molecule by the weight fraction of that molecule and then adding the products, resulting in a weight average carbon number. [0024] In certain embodiments, suitable internal olefin sulfonate surfactants can include bioderived surfactants. Such bioderived internal olefin sulfonates can increase the total renewable carbon content of the surfactants blends described herein. [0025] In certain embodiments, suitable internal olefin sulfonate surfactants can have a weight average carbon number of about 12 to about 24 including, for example, weight average carbon numbers of 16 and 18. The internal olefin sulfonates can be linear, branched, or a combination of linear and branched internal olefin sulfonate surfactants. [0026] To adjust the properties of the surfactant blend for various applications, the surfactant blend can include additional components in various embodiments. For example, bio-based or conventional surfactants can be included in certain embodiments. Additionally, or alternatively, other additives, surfactants and hydrotropes including nonionic, anionic, zwitterionic or amphoteric and cationic surfactants can be included in certain embodiments. [0027] Generally, such additional surfactants can be any known surfactants that do not interfere with the stability of the primary polysaccharide-based surfactants and the internal olefin sulfonate surfactant. For example, suitable anionic surfactants can include sulfonic acid based surfactants such as alkylbenzene sulfonic acids, sulfates, phosphates, carboxylates, sulfosuccinates, and salts thereof. Suitable nonionic surfactants can include ethoxylates, polysaccharides, and alcohol surfactants. Suitable cationic surfactants can include quaternary ammonium salts, betaines, amidobetaines, and sultaines. Suitable hydrotropes can include any known hydrotropes including sodium xylene sulfonates, betaines, hydroxy sultaines, sulfonate proprionates, diproprionates, various organic acids, alkanoates, phosphate esters, and functionalized alkylpolyglycosides. Suitable zwitterionic or amphoteric surfactants can include amine oxide surfactants such as Caloxamine® CPO, aloxamine® LO, Macat® AO-8, Macat® AO-10, Macat® AO-12, Macat® AO-14, Macat® AO-12-2, Macat® AO-11:2, Macat® MCO, Macat® Ultra LMDO, and Macat® Ultra CDO each marketed by the Pilot Chemical Co. (Mason, OH). [0028] Inclusion of non-bio-based, conventional surfactants (such as sodium lauryl sulfate, alpha olefin sulfonate, propylene glycol and ethylene glycol hydrotropes) may not improve the pH or storage stability of the disclosed surfactant blends or stability of any of the individual surfactants of the surfactant blends. As can be appreciated however, inclusion of non-bio-based conventional surfactants can be useful to add additional benefits and tailor the properties of the surfactant blend (e.g., to improve surfactant performance, foam generation, etc.). In certain embodiments, it can also be useful to forego inclusion of any non-bio-based surfactants as such surfactant blends would exhibit high environmental sustainability. [0029] In certain embodiments, the surfactant blend can include the polysaccharide-based surfactant and the internal olefin sulfonate surfactant in an about 1:3 to about 3:1 ratio. In certain embodiments, the ratio of the polysaccharide-based surfactant and the internal olefin sulfonate surfactant can be included in an about 1:1 ratio. In certain embodiments, the polysaccharide-based surfactant and the internal olefin sulfonate surfactant can comprise the majority, by weight, of the surfactant blend. For example, in certain embodiments, the polysaccharide-based surfactant and the internal olefin sulfonate surfactant can be about 50%, by weight, of the surfactant blend, with the remainder constituting other surfactants or hydrotropes. In certain embodiments, the polysaccharide-based surfactant and the internal olefin sulfonate surfactant can comprise substantially 100%, by weight of the surfactant blend. For example, in certain embodiments, the polysaccharide-based surfactant and the internal olefin sulfonate surfactant can comprise about 97%, by weight, of the surfactant blend. [0030] Generally, the surfactant blends described herein can be formed as known in the art. For example, each of the surfactants can be combined and then mixed together using a blender or other mixing equipment. Once formed, the surfactant blends can be stored in a suitable container such as a plastic, glass, or metal container. As can be appreciated, the stability of the surfactant blends can provide a long shelf life to the blends. Examples [0031] To evaluate the stability of polysaccharide-based surfactants, various polysaccharide-based surfactants were dissolved with a pH additive and preservative and allowed to rest for 24 hours. Samples were considered unstable if the surfactant separated into a biphasic or cloudy solution within 24 hours. The formulations and results are depicted in Table 1. Photos of the testing are depicted in FIGS.2 and 3.

TABLE 1 Formulation Tegrasurf Tegrasurf Preservative pH/additive Stability ® ® / % m m m m m m m m

[0032] As depicted in Table 1, the polysaccharide-based surfactants were unstable under both acidic and basic conditions with only neutral pH formulations (Formulations 9 and 10) remaining stable after 24 hours. [0033] To further evaluate the stability of polysaccharide-based surfactants, further samples of pure polysaccharide-based surfactants were stored for one month at both room temperature and at various pH levels. The results of the stability testing are depicted in Table 2. TABLE 2 pH Tegrasurf® Tegrasurf® Tegrasurf® Tegrasurf® 126 126 196 196 [0034] As de

pcte n a e , t e on y poysacc ar e- ase sur actants t at remained stable for an entire month were samples maintained at a neutral pH. All other samples separated into an undesirable biphasic solution demonstrating instability. [0035] Tables 3 and 4 evaluate surfactant blends comprising polysaccharide-based surfactants and internal olefin sulfonate surfactants. Table 3 depicts evaluation results of a C16 internal olefin sulfonate surfactant and surfactant blends while Table 4 depicts evaluation results of a C18 internal olefin sulfonate surfactant and surfactant blends. TABLE 3 Comparative Inventive Example Inventive Example Inventive Example Inventive Example 4 Inventive Example Example 1 1 (50:50 Blend) IOS 250:50 Blend 350:50 Blend 50:50 Blend 550:50 Blend 90 s

TABLE 4 Comparative Inventive Example Inventive Example Inventive Example Inventive Example 9 Inventive Example Example 2 6 (50:50 Blend) IOS 750:50 Blend 850:50 Blend 50:50 Blend 1050:50 Blend C18 IOS + Masopon ® 215 IOS Tegrasurf 196 IOS Tegrasurf 196C IOS Tegrasurf 190C IOS Tegrasurf 190 R T s ate

surfactants (Comparative Examples 1 and 2) had a very high viscosity and are opaque. In contrast, Inventive Examples 1 to 10, being a combination of the C16 and C18 internal olefin sulfonate surfactants in 1:1 ratios with an alkylpolyglycoside surfactant or Tegrasurf 190, 190,C 196, or 196C produced a clear, homogeneous, low viscosity blend. A photo demonstrating the results of Comparative Example 1 and Inventive Example 2 and Comparative Example 2 and Inventive Example 7 are depicted in FIGS.4 and 5 respectively. [0037] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. [0038] It should be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein. [0039] Every document cited herein, including any cross-referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests, or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in the document shall govern. [0040] The foregoing description of embodiments and examples has been presented for purposes of description. It is not intended to be exhaustive or limiting to the forms described. Numerous modifications are possible in light of the above teachings. Some of those modifications have been discussed and others will be understood by those skilled in the art. The embodiments were chosen and described for illustration of various embodiments. Certain embodiments disclosed herein can be combined with other embodiments as would be understood by one skilled in the art. The scope is, of course, not limited to the examples or embodiments set forth herein, but can be employed in any number of applications and equivalent articles by those of ordinary skill in the art. Rather it is hereby intended the scope be defined by the claims appended hereto.

Claims

WHAT IS CLAIMED IS: 1. A surfactant blend composition comprising: a polysaccharide surfactant; and an internal olefin sulfonate surfactant.

2. The surfactant blend of claim 1, wherein the polysaccharide surfactant is an alkylpolyglycoside surfactant.

3. The surfactant blend of claim 1, wherein the polysaccharide surfactant comprises a dextrin- based polysaccharide surfactant or a dextran-based polysaccharide surfactant.

4. The surfactant blend composition of claim 1, wherein the dextrin-based polysaccharide surfactant comprises a maltodextrin.

5. The surfactant blend composition of claim 2, wherein the maltodextrin has a dextrose equivalent value of about 3 to about 25.

6. The surfactant blend composition of claim 2, wherein the maltodextrin has a dextrose equivalent value of about 4.5 to about 7.0.

7. The surfactant blend composition of claim 2, wherein the maltodextrin has a dextrose equivalent value of about 9.0 to about 12.0.

8. The surfactant blend composition of claim 1, wherein at least a portion of the dextran-based polysaccharide surfactant or the dextrin-based polysaccharide surfactant is formed as a reaction product of a polysaccharide and a fatty acid or fatty acid salt.

9. The surfactant blend of claim 6, wherein the fatty acid or fatty acid salt comprises a C4- C20 fatty acid or C4-C20 fatty acid salt.

10. The surfactant blend of claim 1, wherein the internal olefin sulfonate surfactant comprises a linear internal olefin sulfonate surfactant.

11. The surfactant blend of claim 1, wherein the internal olefin sulfonate surfactant comprises a branched linear internal olefin sulfonate surfactant.

12. The surfactant blend of claim 1, wherein the internal olefin sulfonate surfactant comprises a blend of linear and branched internal olefin sulfonate surfactants.

13. The surfactant blend composition of any preceding claim further comprises one or more additional surfactants and hydrotropes.

14. The surfactant blend composition of claim 13, wherein the additional surfactants comprise polysaccharide, nonionic, anionic, zwitterionic, amphoteric, or cationic surfactants.

15. The surfactant blend composition of claim 14, wherein the anionic surfactant comprises a sulfonic acid-based surfactant.

16. The surfactant blend composition of claim 15, wherein the sulfonic acid-based surfactant comprises an alkylbenzene sulfonic acid salt, sulfate, phosphate, or carboxylate.

17. The surfactant blend composition of claim 14, wherein the cationic surfactant comprises a quaternary ammonium salt, a betaine, or a sultane.

18. The surfactant blend composition of claim 14, wherein the nonionic surfactant comprises an ethoxylate, a polysaccharide, or an alcohol.

19. The surfactant blend composition of claim 14, wherein the zwitterionic, amphoteric surfactant comprises a phospholipid, amidobetaines, lauryldimethylamine N-oxide, or lecithin.

20. The surfactant blend composition of claim 13, wherein the hydrotropes comprise sodium xylene sulfonates, betaines and hydroxy sultaines/sulfonates proprionates, diproprionates, organic acids, alkanoates, phosphate esters and functionalized alkylpolyglucosides.

21. A personal care product comprising the surfactant blend composition of any preceding claim.

22. A household cleaning product comprising the surfactant blend composition of any of claims 1-20.

23. A laundry care product comprising the surfactant blend composition of any of claims 1-20.

24. An oilfield production surfactant product comprising the surfactant blend composition of any of claims 1-20.