Thickened compositions and their use

Abstract

Disclosed are a thickening composition and applications thereof, the thickening composition comprising (a) a salt of an N-long chain acyl amino acid, (b) a free N-long chain acyl amino acid, (c) a hydrophilic nonionic surfactant, (d) an amphoteric surfactant, (e) one or more of a sulfonate surfactant, an alkyl glycoside surfactant, an alkanolamide surfactant, and a sodium amphoteric acetate surfactant; the related thickening composition can be used to prepare personal care products, household cleaning products, and industrial cleaning products.

Description

Technical Field

[0001] This invention relates to the field of thickening technology, and particularly to the thickening of cleaning compositions containing amino acid surfactants, and their application in various cleaning products. Background Technology

[0002] Conventionally, anionic surfactants such as alkyl sulfates and polyoxyethylene alkyl sulfates have been widely used as surfactants in hair / body cleansing bases. However, with the increasing frequency of shampooing / showering in recent years, they can sometimes cause dryness and irritation, thus requiring cleaners with less irritation. Furthermore, these are petroleum-derived surfactants, which contradicts the current trend towards sustainability and environmental protection.

[0003] The cosmetics and personal care industry has recognized the growing popularity and importance of sulfate-free and dioxane-free personal care cleaning products containing environmentally friendly, sustainable, and gentle surfactants. Amino acid-based surfactants are considered "greener," gentler, and more sustainable than traditional petroleum-based surfactants.

[0004] Developing high-quality, environmentally friendly surfactants has become a major direction for the surfactant industry, and the replacement of traditional petroleum-based surfactants with amino acid surfactants is an industry trend. Unilever announced that it will halve its use of petroleum-based products by 2025 and reduce it to zero by 2030. L'Oréal announced that it will replace 95% of its petroleum-based products by 2030. Therefore, it is essential to study the formulation systems related to amino acid surfactants.

[0005] Currently, amino acid surfactants are difficult to thicken. The main methods for thickening amino acid surfactants include: 1) using polymer thickeners, such as acrylate copolymers and cellulose compounds; 2) compounding nonionic (e.g., fatty alcohols, fatty acids, alkanolamides, alkyl glycosides), cationic, and amphoteric surfactants (e.g., betaines); 3) adding natural gums and their modifiers, such as carrageenan, guar gum, and xanthan gum. Each of these thickening methods has its own problems. Using polymer thickeners can lead to discoloration at high temperatures, a jelly-like phenomenon at low temperatures, reduced foaming effect and user experience, and a slippery feel after rinsing. Furthermore, high-molecular-weight polymers typically require very high dosages to achieve the desired thickening effect. Compounding with other surfactants for thickening currently focuses on conventional alkanolamides, alkyl glycosides, and betaines, but the thickening effect is limited, resulting in a cloudy, opaque (foggy) appearance, and viscosity decreases over long-term storage. Not only are gelatinous substances difficult to dissolve, but excessive amounts can also cause problems such as jelly-like texture, stringiness, and poor rheological properties. Summary of the Invention

[0006] The inventors discovered that for amino acid surfactant cleaning systems containing N-long-chain acyl amino acid salts, the synergistic effect of (c) a hydrophilic nonionic surfactant and (d) an amphoteric surfactant in the presence of free N-long-chain acyl amino acids can significantly improve the viscosity of the formulation.

[0007] However, sometimes cost constraints necessitate reducing the amount of N-long-chain acyl amino acids / salts and replacing relatively expensive basic amino acids with inorganic bases or organic amines. This presents risks of decreased viscosity, insufficient low-temperature stability, and insufficient transparency. To address this issue, it has been found that it can be resolved by introducing specific (e) components.

[0008] Specifically, the present invention provides the following technical solution.

[0009] The present invention provides a thickening composition comprising (a) a salt of N-long-chain acyl amino acid, (b) free N-long-chain acyl amino acid, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant.

[0010] Alternatively, the thickening composition comprises (a') an N-long-chain acyl amino acid partially neutralized with an alkali, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant. Wherein, (a') the N-long-chain acyl amino acid partially neutralized with an alkali refers to the product of the partial neutralization of the N-long-chain acyl amino acid with an alkali, the product ultimately present in the composition as a salt of the N-long-chain acyl amino acid and unneutralized free N-long-chain acyl amino acid.

[0011] Alternatively, the thickening composition may contain (a'') a base and an N-long-chain acyl amino acid, wherein the molar number of the base is less than that of the N-long-chain acyl amino acid, such that the neutralization degree of the N-long-chain acyl amino acid is less than 100%, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant. Although the base and the N-long-chain acyl amino acid are added to the formulation separately, they will inevitably react. Since the neutralization degree is less than 100%, what ultimately exists in the composition are the salts of the N-long-chain acyl amino acid and unneutralized free N-long-chain acyl amino acids.

[0012] Further, component (e) is introduced, which is selected from one or more of sulfonate surfactants, alkyl glycoside surfactants, alkanolamide surfactants, and sodium amphoteric acetate surfactants. When the amounts of components (a), (a'), and (a'') are insufficient, or when inorganic bases or organic amines are used to neutralize N-long-chain acyl amino acids, component (e) ensures that the viscosity and / or low-temperature stability and / or transparency of the system meet the stringent requirements of the formulation.

[0013] For the N-long-chain acyl amino acid in the composition, the N-long-chain acyl group in the N-long-chain acyl amino acid is derived from a saturated or unsaturated straight-chain or branched fatty acid with 8 to 22 carbon atoms. Further, the N-long-chain acyl group in the N-long-chain acyl amino acid is selected from one or more of octanoyl, decanoyl, undecanoyl, lauroyl, myristoyl, pentadecanoyl, palmitoyl, stearoyl, oleoyl, linoleoyl, isostearoyl, coconut oil fatty acyl, and palm oil fatty acyl, preferably coconut oil fatty acyl or lauroyl, and most preferably lauroyl.

[0014] The amino acids in the N-long-chain acyl amino acids are derived from one or more of glycine, alanine, glutamic acid, sarcosine, aspartic acid, leucine, isoleucine, valine, threonine, proline, phenylalanine, arginine, lysine, and (methyl)taurine. Further, the amino acids in the N-long-chain acyl amino acids are derived from one or more of alanine, glycine, glutamic acid, sarcosine, arginine, lysine, and (methyl)taurine, preferably alanine, and most preferably L-alanine. The N-long-chain acyl (methyl)taurine described in this invention refers to N-long-chain acylmethyl taurine or N-long-chain acyl taurine.

[0015] As an example, N-long-chain acyl amino acids can be selected from cocoyl alanine, lauroyl alanine, cocoyl sarcosine, lauroyl sarcosine, lauroyl glutamic acid, cocoyl glutamic acid, oleyl glutamic acid, cocoyl glycine, lauroyl glycine, stearoyl glutamic acid, etc.

[0016] This invention discovers that N-long-chain acyl amino acids with different structures exhibit varying thickening abilities. Free N-long-chain acylglutamic acid has a weaker thickening effect than its counterparts, N-long-chain acylalanine, glycine, and sarcosine. N-long-chain acylglycine has good thickening ability, but the formulation is prone to precipitation and has poor stability, making it suitable for paste products where high transparency is not required. The surprising discovery of this invention is that, under the same formulation conditions, lauroylalanine's thickening ability far exceeds that of other long-chain acyl amino acids, being 5-10 times stronger than similar structures such as lauroylsarcosine and cocoylalanine (cocoylaminopropionic acid). This superior, much-anticipated thickening ability can completely solve the problem of poor thickening of amino acid surfactant systems and can completely replace the traditional AES system.

[0017] (a) A salt of an N-long-chain acyl amino acid is a salt formed by an N-long-chain acyl amino acid and a base. The base is selected from one or more of inorganic bases, organic amines, and basic amino acids. The inorganic base is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, preferably sodium hydroxide or potassium hydroxide. The organic amine is selected from amines, alkanolamines, etc. For basic amino acids, it is selected from one or more of arginine, lysine, citrulline, ornithine, creatine, histidine, diaminobutyric acid, and diaminopropionic acid, preferably arginine and / or lysine, and most preferably L-arginine. The bases described in (a') and (a'') also have the same definition.

[0018] N-long-chain acyl amino acids can be directly mixed into commercially available long-chain acyl amino acid salts such as Puji's YB02-30 (sodium cocoylaminopropionate), AS02-30 (sodium lauroyl sarcosinate), Tianci's AMIN LS30 (sodium lauroyl sarcosinate), Suzhou Weimei's LA-Arg 30 (lauroyl alanine arginine salt), and LA-Na 30 (sodium lauroyl alanine), or N-long-chain acyl amino acids can be directly mixed into a formulation containing (a) N-long-chain acyl amino acid salts to obtain (a) N-long-chain acyl amino acid salts and (b) free N-long-chain acyl amino acids.

[0019] Alternatively, N-long-chain acyl amino acids can be partially neutralized with a base to obtain (a') N-long-chain acyl amino acids partially neutralized with a base. Alternatively, a base and an N-long-chain acyl amino acid can be added to the formulation separately (corresponding to (a'')). Since the base is used for partial neutralization and the N-long-chain acyl amino acid is in excess, the system will contain both the neutralized N-long-chain acyl amino acid salt and the unneutralized free N-long-chain acyl amino acid, which is essentially equivalent to (a) the salt of the N-long-chain acyl amino acid + (b) the free N-long-chain acyl amino acid.

[0020] Increasing the amount of N-long-chain acyl amino acid salts and free N-long-chain acyl amino acids can improve the viscosity of the composition. However, if too much is used, the formulation will be too viscous; if too little is used, the formulation will lack sufficient viscosity.

[0021] From a cost control perspective, the weight percentage of components (a), (a'), or (a'') in the thickening composition should be below 10 wt%, preferably below 8 wt%. Formulators can choose whether to introduce component (e) based on the specific viscosity requirements of the actual product. Introducing component (e) is especially recommended for products with high viscosity requirements.

[0022] From the perspective of cost control, (a) the salt of N-long-chain acyl amino acids is an inorganic base salt or an organic amine salt of N-long-chain acyl amino acids, such as one or more of sodium salts, potassium salts, ammonium salts, and TEA salts. The base mentioned in (a') and (a'') is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, amines, and alkanolamines.

[0023] Inorganic base salts and organic amine salts of N-long-chain acyl amino acids have lower solubilizing properties for free N-long-chain acyl amino acids than basic amino acid salts. In this case, it is preferable to reduce the amount of free N-long-chain acyl amino acids in the formulation system. Furthermore, for (a') and (a''), the degree of neutralization is controlled between 80% and 95%, preferably above 85%. For example, the degree of neutralization is 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, and 94%. If the neutralization is too low, there will be too much free N-long-chain acyl amino acid, and the formulation will easily precipitate. If the neutralization is too high, there will be insufficient free N-long-chain acyl amino acids, and the thickening effect will be limited. The aforementioned degree of neutralization refers to the percentage of N-long-chain acyl amino acids that are neutralized. For example, 80% neutralization means that 80% of all N-long-chain acyl amino acids are neutralized by the base to form salts, leaving 20% ​​as free N-long-chain acyl amino acids. Correspondingly, for component (a), the molar ratio (a) / (b) to component (b) is 4-19.

[0024] The synthesis process of N-long-chain acyl amino acid surfactants can refer to the general synthesis methods of N-acyl amino acid type surfactants, and is divided into direct methods and indirect methods. Direct synthesis methods from fatty acid raw materials include enzyme-catalyzed synthesis and dehydration condensation. Indirect synthesis methods include acylation of fatty acid acyl chlorides, hydrolytic acylation of fatty acid nitriles, acylation of fatty acid anhydrides, and amide carbonylation reactions. A preferred method is preparation via the amino reaction of fatty acyl chlorides with amino acids (Shotten-Baumann condensation reaction or Shotten-Baumann reaction).

[0025] A typical preparation process suitable for this invention is as follows: amino acids and sodium hydroxide are dissolved in water or a mixture of water and acetone to obtain an amino acid salt solution; then lauroyl chloride and sodium hydroxide solution are slowly added dropwise to the amino acid salt solution, controlling the pH of the reaction system; after the addition is complete, post-processing of the product is performed. Representative methods are disclosed in CN1798821A, US6703517B2, CN102875409B, JPH0570418A, etc.

[0026] For the post-processing of N-long-chain acyl amino acid products, conventional methods such as recrystallization, water washing, and drying can be used. A preferred post-processing step includes the following steps: mixing the crude N-long-chain acyl amino acid with a solvent, optionally stirring, and controlling the temperature T of the mixed system to be above the melting point of the long-chain fatty acid and below the melting point of the N-long-chain acyl amino acid. The solvent is water, an organic solvent, or a mixture of water and an organic solvent. After temperature control, solid-liquid separation is performed. Related methods are disclosed by the inventors in CN202210867760.7 and PCT / CN2022 / 107270, the contents of which are incorporated herein by reference.

[0027] For component (c), hydrophilic nonionic surfactants, it refers to a class of nonionic surfactants that are hydrophilic and can be dispersed or dissolved in water to form emulsions or translucent to transparent solutions.

[0028] The present invention primarily prefers O / W type emulsifiers, or solubilizing nonionic surfactants, or nonionic surfactants with HLB 6 or higher.

[0029] The O / W type emulsifier refers to a type of substance that enables the oil phase (O, abbreviated as O) to be uniformly dispersed in the aqueous phase (Water, abbreviated as W) in the form of tiny droplets, forming an oil-in-water (O / W) emulsion. In this invention, the O / W type emulsifier can stabilize free N-long-chain acyl amino acids, ensuring they do not precipitate, and can also have a synergistic effect on thickening.

[0030] The solubilizing nonionic surfactant refers to a nonionic surfactant with solubilizing properties, which can dissolve lipophilic raw materials in water. In this invention, it specifically refers to a surfactant that can dissolve lipophilic free N-long-chain acyl amino acids in water, ensuring that they do not precipitate, and can also have a synergistic effect on thickening.

[0031] For nonionic surfactants with an HLB value of 6 or higher, the HLB value reflects the relative strength of the hydrophilic and lipophilic groups, indicating their partitioning ability in the aqueous and oil phases. An HLB value of 6 or higher can maximize the stability of free N-long-chain acyl amino acids. This invention particularly prefers nonionic surfactants with an HLB value of 8 or higher, more preferably 10, 12, or even 14 or higher. If the HLB value is too low (e.g., 2, 3, 4), its hydrophilicity is too weak, which is detrimental to thickening and also to maintaining the transparency and low-temperature stability of the formulation. If the HLB value is high, for example, 14 or higher, it will be very beneficial for thickening and maintaining the low-temperature stability of the formulation. Suitable HLB values ​​are, for example, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, and 35. This invention has found that HLB values ​​of 12 or higher, such as 12, 14, 16, or 18, are highly advantageous for preparing completely transparent products. Exemplary examples of HLB values ​​of 12 or higher include PEG-120 methyl glucoside dioleate, PEG-150 pentaerythritol tetrastearate, polyglycerol-10 laurate, and PEG-160 sorbitan triisostearate.

[0032] The aforementioned HLB only reflects the relative strength of hydrophilic and lipophilic groups. This invention also unexpectedly discovered that the hydrophilicity of the hydrophilic groups themselves has a significant impact on thickening. To further improve the thickening effect, in addition to HLB, it is necessary to focus on the hydrophilicity of the hydrophilic groups themselves.

[0033] To facilitate the characterization of the hydrophilic contribution of hydrophilic groups (defined in this invention as "hydrophilicity value"), this invention adopts the Davis method from HLB calculation methods. According to the Davis method, each chemical group (such as –OH, –COO⁻, –CH3, etc.) is assigned a value reflecting its hydrophilicity or lipophilicity. In this invention, the "hydrophilicity value" is equal to the sum of the values ​​assigned to all hydrophilic chemical groups in the surfactant based on the Davis method.

[0034] For example, for hydrophilic groups, -OH (hydroxyl group) is +1.9, -O- (ether group) is +1.3, -COO- (ester group) is +2.4, -COOH (carboxyl group) is +2.1, -SO3⁻ (sulfonic acid group) is +11.0, -(CH2-CH2-O)- (polyoxyethylene unit EO) is +0.33, and -O-CH2CH(OH)CH2- (polyglycerol unit) is 1.77, etc. More values ​​can be found in the values ​​disclosed in the Davis method. The overall value of the dehydrated sorbitol ring is -1.5. Since it is already negative, it is not considered a hydrophilic group in this invention. (c) If the hydrophilicity value of a hydrophilic nonionic surfactant is too low, its thickening effect is limited, and it is impossible to obtain a product with ultra-high viscosity; increasing the hydrophilicity value is beneficial to improving the thickening performance.

[0035] For example, for Tween 20, calculated using the Davis method, its hydrophilicity value = 5.7 (3 -OH groups) + 2.4 (1 ester group) + 6.6 (20EO) = 14.7. Although Tween 20 has a high overall HLB value, its thickening effect is limited due to its hydrophilicity value of only 14.7. For PEG-20 glyceryl triisostearate, its hydrophilicity value = 7.2 (3 ester groups) + 6.6 (20EO) = 13.8; for PEG-40 dehydrated sorbitan stearate, its corresponding hydrophilicity value = 5.7 (3 -OH groups) + 2.4 (1 ester group) + 13.2 (40EO) = 21.3; for PEG-60 glyceryl isostearate, its corresponding hydrophilicity value = 3.8 (2 -OH groups) + 2.4 (1 ester group) + 19.8 (60EO) = 26; for polyglycerol-6 monooleate, The corresponding hydrophilicity value is 10.62 (6 polyglycerol units -O-CH2CH(OH)CH2-) + 1.9 (1 -OH) + 2.4 (ester group) = 14.92; for polyglycerol-8 monooleate, the corresponding hydrophilicity value is 14.16 (8 polyglycerol units) + 1.9 (1 -OH) + 2.4 (ester group) = 18.46; for polyglycerol-10 laurate, the corresponding hydrophilicity value is 17.7 (10 polyglycerol units) + 1.9 (1 -OH) + 2.4 (ester group) = 22. PEG-20 glycerol triisostearate and polyglycerol-6 monooleate have relatively low hydrophilicity values, resulting in limited thickening effects. Under the same conditions, increasing the hydrophilicity value is beneficial for enhancing the thickening ability of nonionic surfactants. The present invention preferably (c) has a hydrophilicity value of 15 or higher for the hydrophilic nonionic surfactant (calculated based on the Davis method), and more preferably 20, 25 or even 30 or higher.

[0036] Furthermore, (c) the hydrophilic nonionic surfactant can be of the polyoxyethylene type, polyol type, alkylamide type, etc. Preferably, the hydrophilic nonionic surfactant of this invention comprises a polyoxyethylene unit or a polyglycerol unit in its hydrophilic group.

[0037] Polyoxyethylene units can be understood as EO repeating units, PEG units, or oxyethylene units. The higher the number of polyoxyethylene units, the better the hydrophilicity, which is beneficial for thickening and low-temperature stability. It is advantageous to have more than 50 PEG units, preferably 60, 80, or 100 or more, such as 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and 160. For example, substances with a high number of PEG units, such as PEG-120 methyl glucoside dioleate, PEG-150 pentaerythritol tetrastearate, PEG-160 sorbitan triisostearate, PEG-100 stearate, and PEG-60 glyceryl isostearate, all exhibit excellent thickening and low-temperature stability.

[0038] Polyglycerol units refer to polyglycerol groups obtained by glycerol polymerization. The more polyglycerol units there are, the better the hydrophilicity, which is beneficial for thickening and low-temperature stability. It is advantageous to have 6 or more polyglycerol units, preferably 8 or 10 or more, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. For example, substances with a high number of polyglycerol units, such as polyglycerol-10 laurate, exhibit excellent thickening and low-temperature stability.

[0039] Furthermore, this invention has found that the number of carbon atoms in the hydrophobic group of a hydrophilic nonionic surfactant affects its thickening properties. A carbon number greater than 10 (e.g., cocoyl, lauryl, stearyl) is beneficial for thickening. A carbon number less than 10 (e.g., octyl, decyl) is detrimental to thickening. Additionally, branched hydrophobic groups are beneficial for thickening. For example, polyglycerol-10 monoisostearate is superior to polyglycerol-10 monostearate. This may be because the branched structure enhances the three-dimensional spatial structure of the surfactant.

[0040] Besides hydrophilicity and HLB value, the spatial configuration of (c) hydrophilic nonionic surfactants is also very important. For example, nonionic surfactants with low HLB values ​​may still have good thickening properties if they have a three-dimensional spatial structure. Typically, if the chemical structure of (c) hydrophilic nonionic surfactants has two or more hydrophobic groups, especially three or more, it will not be a linear structure but a three-dimensional spatial structure. It is speculated that this spatial structure can effectively promote the formation of micelle aggregates.

[0041] In addition, nonionic surfactants derived from polyhydroxy compounds such as pentaerythritol, glucose / methylglucose, dehydrated sorbitol, sorbitol, and glycerol are generally obtained by esterification of polyhydroxy compounds, hydrophilic compounds (such as ethylene oxide and polyglycerol), and fatty acids. The hydroxyl groups are connected to two or more (preferably three or more) hydrophobic groups, and they have the aforementioned three-dimensional spatial structure.

[0042] For example, polyglycerol-3-methylglucose distearate is less hydrophilic than polyglycerol-10 laurate, but it has a stronger thickening ability due to its three-dimensional structure. Another example is PEG-150 pentaerythritol tetrastearate, which is derived from pentaerythritol and has a very good three-dimensional structure, exhibiting extremely strong thickening ability.

[0043] The amount of (c) hydrophilic nonionic surfactant is related to the amount of free N-long-chain acyl amino acids and amphoteric surfactants. If the amount of free N-long-chain acyl amino acids or amphoteric surfactants is high, the amount of (c) hydrophilic nonionic surfactant can be appropriately reduced. Conversely, if the amount of free N-long-chain acyl amino acids or amphoteric surfactants is low, the amount of (c) hydrophilic nonionic surfactant can be appropriately increased. Generally, the weight percentage of (c) hydrophilic nonionic surfactant in the thickening composition is 0.05-5 wt%, preferably 0.1-4 wt%, more preferably 0.5-3 wt%. For example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%. Although an excessive amount of (c) hydrophilic nonionic surfactant is beneficial for thickening, it can negatively affect the wash feel / touch of the product to some extent.

[0044] For component (d), amphoteric surfactants refer to surfactants whose molecular structure contains both anionic groups (such as carboxylate, sulfonate, and phosphate groups) and cationic groups (such as ammonium and quaternary ammonium groups). Representative examples include betaine derivatives, imidazoline derivatives, amine oxide derivatives, and sodium amphoteric acetate derivatives. This invention has found that betaine derivatives have the best thickening effect, safety, and user experience.

[0045] Furthermore, (d) the amphoteric surfactant is a betaine-based amphoteric surfactant. The betaine-based amphoteric surfactant is selected from one or more of alkyl betaine (Formula I), alkylamidopropyl betaine (Formula II), alkyl hydroxysulfonyl betaine (Formula III), and alkylamidopropyl hydroxysulfonyl betaine (Formula IV).

[0046] (I); (II); (III); (VI) This invention, through systematic research, has found that thickening performance is significantly correlated with the hydrophilicity of both (c) the hydrophilic nonionic surfactant and (d) the amphoteric surfactant. When the hydrophilic group of the (c) hydrophilic nonionic surfactant is highly hydrophilic (e.g., PEG-150 pentaerythritol tetrastearate, PEG-160 sorbitan triisostearate), the requirement for the hydrophilicity of the (d) amphoteric surfactant can be reduced, and it may even be unnecessary to use the (d) amphoteric surfactant. However, when the hydrophilic group of the (c) hydrophilic nonionic surfactant is insufficiently hydrophilic, it is particularly necessary to select a (d) amphoteric surfactant with strong hydrophilicity. For example, when (c) the hydrophilicity value of the hydrophilic nonionic surfactant is below 50, 40, and especially 30 (calculated based on the Davis method), or the number of PEG units is below 80, 65, and especially 50, or the number of polyglycerol units is below 10, 8, and especially 6, the amphoteric surfactant is preferably a highly hydrophilic alkyl hydroxysulfonate betaine, thus ensuring that the thickening composition has very excellent thickening properties.

[0047] The amount of (d) amphoteric surfactant used is related to the amount of free N-long-chain acyl amino acids and nonionic surfactants. If the amount of free N-long-chain acyl amino acids or nonionic surfactants is high, the amount of (d) amphoteric surfactant can be appropriately reduced. Conversely, if the amount of free N-long-chain acyl amino acids or nonionic surfactants is low, the amount of (d) amphoteric surfactant can be appropriately increased. Generally, the weight percentage of (d) amphoteric surfactant in the thickening composition is 0.1-15 wt%, preferably 1-10 wt%, more preferably 2-8 wt%. For example, it can be 0.5 wt%, 0.7 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, or 8 wt%. As the amount of (d) amphoteric surfactant increases, the improvement in its thickening effect gradually weakens, and it will also affect the wash feel / touch feel of the product.

[0048] For component (e), it is selected from one or more of sulfonate surfactants, alkyl glycoside surfactants, alkanolamide surfactants, and sodium amphoteric acetate surfactants.

[0049] Sulfonate surfactants are a class of surfactants containing sulfonate groups. Further, they are selected from one or more of the following: α-olefin sulfonates (representative components: C14-16 α-olefin sulfonate sodium, C12-14 α-olefin sulfonate sodium), succinate sulfonates (representative components: disodium lauryl ether sulfosuccinate, sodium dioctyl sulfosuccinate), and acyl hydroxyethanesulfonates (acyl-substituted sulfonates, representative components: sodium cocoyl hydroxyethanesulfonate, sodium lauroyl hydroxyethanesulfonate, sodium lauroyl methyl hydroxyethyl sulfonate).

[0050] Alkyl glycoside surfactants are classified according to the "carbon chain length of fatty alcohol" into short carbon chains (C8-C10), medium carbon chains (C12-C14), long carbon chains (C16-C18), and combinations of different carbon chains. They are further selected from one or more of octyl glucoside, decyl glucoside, cocoyl glucoside, lauryl glucoside, stearyl glucoside, palmityl glucoside, APG0810, APG0814, APG1214, APG1618, APG1216, APG0816, and APG2022.

[0051] Alkanolamide surfactants are generated by the reaction of "fatty acid + alkanolamine" and belong to nonionic surfactants. They are further selected from one or more of cocamidomethyl MEA, cocamidomethyl MEA, cocamidodiethanolamine, stearamide MEA, cocamidomethyl PA, and cocamidopropyl dimethylamine.

[0052] The core structure of sodium amphoteric acid surfactants is "fatty acid acyl group + sodium aminoacetate", which is further selected from one or more of sodium lauroyl amphoteric acid, sodium cocoyl amphoteric acid, disodium cocoyl amphoteric acid, and disodium lauroyl amphoteric acid.

[0053] The recommended weight percentage of component (e) in the thickening composition is 1-20 wt%, for example, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, or 20 wt%. Higher component (e) content is more conducive to thickening, but excessive amounts can destroy the refreshing feel of amino acid surfactants, especially lauroyl alanine.

[0054] The thickening composition may further contain other ingredients such as preservatives, fragrances / flavors, conditioning agents, dyes, chelating agents, extracts, amino acids, nucleic acids, vitamins, enzymes, anti-inflammatory agents, bactericides, antioxidants, UV absorbers, antiperspirants, pH adjusters, pearlescent agents, etc.

[0055] The thickening composition of the present invention can be used to prepare personal care products, household cleaning products, industrial cleaning products, etc. The personal care products include shower gel, shampoo, facial cleanser, makeup remover, shaving products, or hand soap; the household cleaning products include laundry detergent, dish soap, furniture and floor cleaner, fabric cleaner, or kitchen cleaner.

[0056] In each implementation, details such as the selection of types and dosages not discussed can be referred to the relevant guidance of other implementations if there is no conflict in the content. For the sake of brevity, each implementation has not been described in detail.

[0057] Unless otherwise specified, "above," "below," and "A~B" in this invention all include the stated number. Since the solid content of raw materials varies among different manufacturers, the weight percentage (wt%) of each raw material mentioned in this invention refers to the weight percentage of that component after conversion to 100%. For example, if 10wt% sodium cocoaminopropionate (30% solid content) is added, the actual weight percentage of sodium cocoaminopropionate after conversion to 100% is 3wt%.

[0058] Compared with the prior art, the present invention has the following beneficial technical effects: 1. This invention is the first to discover that, in the presence of free N-long-chain acyl amino acids, the combination of (c) a hydrophilic nonionic surfactant, (d) an amphoteric surfactant, and (e) component, the four components work synergistically to significantly improve the viscosity of the formulation.

[0059] 2. The remarkable discovery of this invention is that, under the same formulation conditions, lauroyl alanine has a thickening ability far exceeding that of other long-chain acyl amino acids, being 5-10 times that of lauroyl sarcosine, cocoyl alanine (cocoyl amino propionic acid), etc., which have similar structures.

[0060] 3. By using a lower content of N-long-chain acyl amino acids / salts and replacing relatively expensive basic amino acids with inorganic bases / organic amines, the viscosity and / or low-temperature stability and / or transparency of the system can be ensured to meet the stringent requirements of the formulation by introducing specific (e) components (selected from one or more of sulfonate surfactants, alkyl glycoside surfactants, alkanolamide surfactants, and sodium amphoteric acetate surfactants).

[0061] The present invention will be further illustrated below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalents also fall within the scope defined by the appended claims.

[0062] Example 1. Description of test materials LA stands for lauroyl alanine (from Suzhou Weimei), Arg stands for arginine (from Suzhou Weimei), CMMEA stands for cocamidomethyl MEA, 430 stands for sorbitol polyether-30 tetraoleate (purchased from Kao), 150 stands for PEG-150 pentaerythritol tetrastearate (purchased from Heda), 160 stands for PEG-160 dehydrated sorbitol triisostearate (purchased from Kao), DOE120 stands for PEG-120 methyl glucodioleate (purchased from Lubrizol), CAB stands for cocamidopropyl betaine, and LAB stands for lauroamide propyl betaine.

[0063] The 30% marked in the raw materials (e.g., sodium cocoaminopropionate (30%)) means that the added raw materials are solutions with a solid content of 30%. For example, if 100g of sodium cocoaminopropionate (30%) is added, the actual amount of sodium cocoaminopropionate added is 30g.

[0064] 2. Test instruments Viscometer: Lichen rotational viscometer, model LC-NDJ-55.

[0065] 3. Experimental Procedure Unless otherwise specified, weigh each component according to the formula, heat to 70-85℃, and keep stirring until homogeneous. After the prepared sample has stabilized, remove it, select a suitable rotor and speed, and test the sample viscosity with a viscometer. Low-temperature testing involves keeping it at -5℃ for 48 hours for observation.

[0066] Table 1.1 Effect of free N-long-chain acyl amino acids (sodium cocoylaminopropionate)

[0067] The results showed that for formulations containing sodium cocoylaminopropionate, the solution had almost no viscosity if free N-long-chain acyl amino acids were lacking; however, after adding lauroyl alanine, the viscosity increased by several tens of times, and the solution became transparent and had good low-temperature stability.

[0068] Table 1.2 Effect of free N-long chain acyl amino acids (lauroyl glycine, LA)

[0069] The results showed that, whether it was lauroylglycine or lauroylalanine, if it was completely neutralized with alkali, there were no free N-long-chain acyl amino acids, and the formulation solution had almost no viscosity; if it was partially neutralized with alkali (80% neutralization), about 20% of the N-long-chain acyl amino acids in the formulation were in a free state, and the solution viscosity increased significantly.

[0070] Table 1.3 Effect of free N-long-chain acyl amino acids (lauroyl sarcosine)

[0071] The results showed that for formulations containing lauroyl sarcosine, if the free N-long-chain acyl amino acid is lacking (100% neutralization with alkali), the solution has no viscosity; however, if the solution is partially neutralized with alkali (80% neutralization), the viscosity of the solution increases, especially when the hydrophilic nonionic surfactant is 150 or 160, the viscosity increase is significant.

[0072] Table 1.4 Effect of free N-long-chain acyl amino acids (LA)

[0073]

[0074] The results showed that, compared to lauroyl sarcosine (1-9 to 1-12), the thickening effect of the formulation containing lauroyl alanine (1-13 to 1-20) was improved by more than 5-10 times. Partial neutralization of lauroyl alanine with a basic amino acid (arginine) resulted in significantly better low-temperature stability than partial neutralization with an inorganic base (sodium hydroxide).

[0075] Table 2 Effects of amphoteric surfactants

[0076] The results showed that the solution viscosity was low if the formulation lacked amphoteric surfactants. Among amphoteric surfactants, betaine-based amphoteric surfactants showed the best thickening effect under the same conditions.

[0077] Table 3.1 Effect of hydrophilic nonionic surfactants

[0078]

[0079] The results showed that the solution viscosity was low when the formulation lacked hydrophilic nonionic surfactants. The more polyoxyethylene units (PEG units) a hydrophilic nonionic surfactant contained, the better it was for thickening and improving formulation transparency and low-temperature stability (preferably PEG 50 or higher). In formulations 3-10, the presence of PEG-100 stearate effectively increased the formulation viscosity, but the presence of non-hydrophilic glycerol stearate resulted in a semi-transparent, semi-hazy appearance. Furthermore, the three-dimensional spatial structure of the hydrophilic nonionic surfactant (e.g., 150) also contributed to improved thickening ability.

[0080] Table 3.2 Effect of hydrophilic nonionic surfactants

[0081] The results showed that alkanolamide nonionic surfactants had stronger thickening ability than alkyl glycoside nonionic surfactants, but weaker than PEG nonionic surfactants with more than 50 PEG units. The non-hydrophilic Span (HLB4.3) lacked PEG units and therefore had poor thickening performance. Tween, limited by having only 20 PEG units and weak hydrophilicity of its hydrophilic groups, had limited thickening ability.

[0082] Table 3.3 Effect of hydrophilic nonionic surfactants

[0083]

[0084]

[0085] The results showed that the more polyglycerol units a hydrophilic nonionic surfactant has, the better it is for thickening and improving formulation transparency (preferably, more than 6 polyglycerol units are preferred). Furthermore, the branched / three-dimensional structure of hydrophilic nonionic surfactants is beneficial for improving thickening ability (e.g., formulations 3-16, 3-22); however, hydrophobic groups with fewer than 10 carbon atoms are detrimental to thickening (e.g., formulations 3-28, 3-29), with approximately 12 carbon atoms being particularly preferred. Non-hydrophilic nonionic surfactants such as polyglycerol-10-decanoate isostearate (HLB 3) and polyglycerol-10-decanoate oleate (HLB 3) have relatively poor thickening effects and formulation transparency.

[0086] Table 4. Effect of component (e) on alkanolamide surfactants (wt% is the content after 100% conversion)

[0087] The results showed that the viscosity of the composition was effectively improved due to the introduction of the alkanolamide surfactant in component (e).

[0088] Table 5 Effect of neutralization degree (wt% is the content after 100%)

[0089] The results showed that as the degree of neutralization increased, the amount of free lauroyl alanine (LA) gradually decreased, and the thickening ability weakened. For cases where inorganic bases partially neutralize N-long-chain acyl amino acids, controlling the degree of neutralization above 80% is beneficial for improving low-temperature stability and preventing material precipitation.

[0090] Table 6 Effect of component (e) on sodium amphoteric acetate surfactants (wt% is the content after 100%)

[0091] The results showed that, due to the introduction of sodium amphoteric acid surfactant in component (e), even with only 5% lauroyl alanine added, the viscosity of the composition could still exceed 20,000 mPa·s.

[0092] Table 7 Effect of LA dosage (wt% is the content after 100%)

[0093] The results showed that the viscosity of the composition gradually increased with the increase of lauroyl alanine (LA) dosage.

[0094] Table 8 Effect of sulfonate surfactants on component (e) (wt% is the content after 100%)

[0095]

[0096] The results showed that, due to the introduction of sulfonate surfactants in component (e), the viscosity of the composition still reached a high value even with only 5% lauroyl alanine added. Furthermore, if free lauroyl alanine (such as 8-4) was lacking, even with increased component (e), the increase in viscosity was relatively limited, and a large amount of milky white precipitate was observed, indicating system instability.

[0097] Table 9 Effect of alkyl glycoside surfactants on component (e) (wt% is the content after 100%)

[0098] The results showed that, due to the introduction of alkyl glycoside surfactants in component (e), the viscosity of the composition still reached a high value even with only 5% lauroyl alanine added; lauroyl glucoside was significantly more effective than decyl glucoside. Furthermore, without free lauroyl alanine (such as 9-3), even increasing the amount of component (e) did not effectively improve the viscosity.

[0099] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

Claims

1. A thickening composition, characterized in that, The composition comprises (a) a salt of an N-long-chain acyl amino acid, (b) a free N-long-chain acyl amino acid, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant. Alternatively, the composition comprises (a') an N-long-chain acyl amino acid neutralized with an alkali portion to a degree of neutralization of less than 100%, such that it contains unneutralized free N-long-chain acyl amino acids, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant. Alternatively, the composition comprises (a'') a base and an N-long-chain acyl amino acid, wherein the molar number of the base is less than that of the N-long-chain acyl amino acid, such that the neutralization degree of the N-long-chain acyl amino acid is less than 100%, thereby containing free N-long-chain acyl amino acids, (c) a hydrophilic nonionic surfactant, and (d) an amphoteric surfactant. Furthermore, (d) the amphoteric surfactant is a betaine-based amphoteric surfactant; Furthermore, the composition further comprises one or more of the following: (e) sulfonate surfactants, alkyl glycoside surfactants, alkanolamide surfactants, and sodium amphoteric acetate surfactants.

2. The thickening composition according to claim 1, characterized in that, The N-long chain acyl group in the N-long chain acyl amino acid is derived from saturated or unsaturated straight-chain or branched fatty acids with 8 to 22 carbon atoms. And / or, the amino acids in the N-long-chain acyl amino acids are derived from one or more of alanine, glycine, glutamic acid, sarcosine, arginine, lysine, and (methyl)taurine; And / or, the salt of the N-long-chain acyl amino acid is one or more of the following: inorganic base salt, organic amine salt, and basic amino acid salt of N-long-chain acyl amino acid; And / or, the base is selected from one or more of inorganic bases, organic amines, and basic amino acids.

3. The thickening composition according to claim 1, characterized in that, The N-long-chain acyl amino acid mentioned in (a), (a'), (a''), and (b) is lauroyl alanine.

4. The thickening composition according to claim 1, characterized in that, (a) The salt of N-long chain acyl amino acid is one or more of the sodium salt, potassium salt, ammonium salt, and TEA salt of N-long chain acyl amino acid; the base mentioned in (a') and (a'') is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, amine, and alkanolamine.

5. The thickening composition according to claim 1, characterized in that, (c) The hydrophilic nonionic surfactant is an O / W type emulsifier; or a solubilizing nonionic surfactant; or a nonionic surfactant with HLB of 6 or more, preferably 8 or more, and more preferably 12 or more.

6. The thickening composition according to claim 1, characterized in that, (c) The hydrophilic nonionic surfactant has a hydrophilicity value of 15 or higher, preferably 20 or higher, more preferably 25 or higher, wherein the hydrophilicity value is equal to the sum of the values ​​assigned to all hydrophilic chemical groups in the surfactant based on the Davis method.

7. The thickening composition according to claim 1, characterized in that, (c) The hydrophilic nonionic surfactant has a hydrophilic group comprising polyoxyethylene units, preferably having 50 or more polyoxyethylene units; and / or, the hydrophilic nonionic surfactant has a hydrophilic group comprising polyglycerol units, preferably having 6 or more polyglycerol units.

8. The thickening composition according to claim 1, characterized in that, (c) The hydrophilic nonionic surfactant includes one or more of PEG-120 methylglucose difatty acid ester, PEG-120 methylglucose trifatty acid ester, PEG-150 pentaerythritol tetrafatty acid ester, PEG-160 sorbitan trifatty acid ester, PEG-100 fatty acid ester, polyglycerol-3 methylglucose difatty acid ester, and polyglycerol-10 fatty acid ester.

9. The thickening composition according to claim 1, characterized in that, For component (e), the sulfonate surfactant is selected from one or more of α-olefin sulfonates, succinate sulfonates, and acyl hydroxyethanesulfonates; Alkyl glycoside surfactants are selected from one or more of the following: octyl glucoside, decyl glucoside, cocoyl glucoside, lauryl glucoside, stearyl glucoside, palmityl glucoside, APG0810, APG0814, APG1214, APG1618, APG1216, APG0816, and APG2022. Alkanolamide surfactants are selected from one or more of cocamidomethyl MEA, cocamidoMEA, cocamidodiethanolamine, stearamide MEA, cocamidoMIPA, and cocamidopropyl dimethylamine; Sodium amphoteric acid surfactants are selected from one or more of sodium lauroyl amphoteric acid, sodium cocoyl amphoteric acid, disodium cocoyl amphoteric acid, and disodium lauroyl amphoteric acid.

10. The thickening composition according to claim 1, characterized in that, The weight percentage of component (a), (a') or (a'') in the thickening composition is 10 wt% or less, preferably 8 wt% or less; and the weight percentage of component (e) in the thickening composition is 1-20 wt%, preferably 2-15 wt%.

11. The thickening composition according to claim 1, characterized in that, For component (a), its molar ratio (a) / (b) with that of component (b) is 4-19; For (a') and (a''), the degree of neutralization is above 80%, preferably above 85%, and below 95%.

12. The thickening composition according to claim 1, characterized in that, (c) The hydrophilic nonionic surfactant in the thickening composition comprises 0.05-5 wt% by weight, preferably 0.1-4 wt%; And / or, (d) the amphoteric surfactant is present in the thickening composition at a weight percentage of 0.1-15 wt%, preferably 1-10 wt%.

13. The use of a thickening composition as described in any one of claims 1-12 in the preparation of personal care products, household cleaning products, and industrial cleaning products.

14. A cleaning product comprising the thickening composition according to any one of claims 1-12.

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