A weak acid low sudsing liquid detergent composition

Abstract

The present application relates to the field of detergent, disclose a kind of weak acid low foam liquid detergent composition, total active content is 15~30wt%, including the following ingredients: modified oil ethoxylate sulfonate 5~15wt%, fatty alcohol polyether type nonionic surfactant 4~8wt%, thickening agent polyethylene glycol double fatty acid ester 0.5~2.0wt%, long chain fatty acid 0.5~1.5wt%, base neutralizer, other auxiliary 0~10wt%, solvent.The liquid detergent composition of the present application is weakly acidic, therefore has lower irritation, more skin-friendly, not hurt hand characteristics, on this basis, the liquid detergent composition of the present application also successfully realizes that fatty acid is introduced into weakly acidic system, and modified oil ethoxylate sulfonate is introduced into weakly acidic system without reducing the viscosity of system, so that weakly acidic liquid detergent composition has low foam specific and ideal viscosity.

Description

Technical Field

[0001] This invention relates to the field of detergents, and more particularly to a weakly acidic, low-foaming liquid detergent composition. Background Technology

[0002] Human skin is slightly acidic, while commercially available liquid detergents are typically slightly alkaline. Therefore, slightly acidic detergents are considered more compatible with human skin and may offer lower irritation, be gentler on the skin, and be less damaging to hands. In recent years, slightly acidic detergents have become increasingly popular in hand-washing laundry products, such as those for infants, collar cleaners, or underwear washes. Therefore, slightly acidic liquid detergents have significant market potential.

[0003] On the other hand, since consumers typically judge the rinsing effectiveness by the amount of foam during washing, the most common method in existing technologies to control the foam of detergent products and achieve low-foaming and easy-rinsing results is to add fatty acid soaps or silicone defoamers to the formula. Fatty acid soaps, due to their molecular characteristics, are more suitable for weakly alkaline formulas (in weakly acidic systems, fatty acids mostly exist in protonated form, with very limited solubility), and usually need to be added at a concentration of more than 1% to achieve a good defoaming effect. Silicone defoamers, on the other hand, are usually dispersed in the system in emulsion form, and have performance defects such as poor stability in the formula and easy failure after demulsification.

[0004] In existing technologies, other low-foaming surfactants are also used to achieve low-foaming and easy-rinse formulations. For example, studies have shown that modified oleoethoxylated sulfonates have good low-foaming and easy-rinse properties, but they significantly reduce viscosity, making them difficult to thicken effectively using conventional methods. Therefore, modified oleoethoxylated sulfonates are often recommended for use in pod products and concentrated detergent systems where viscosity adjustment is not required. For instance, patent CN111139144A discloses a low-temperature easy-rinse ultra-concentrated liquid detergent and its preparation method, utilizing the good solubility, viscosity reduction, and easy-rinse properties of modified oleoethoxylated sulfonates (SNS-80). Another example is patent CN110331049A, which utilizes the viscosity-reducing properties of SNS-80 in combination with viscous alkyl glycosides to achieve good low-temperature fluidity and facilitate production. Yet another example is patent CN109181894A, which discloses an ultra-concentrated detergent containing oleoethoxylated sulfonates, possessing strong detergency, low viscosity, and excellent high and low temperature fluidity.

[0005] In summary, how to introduce fatty acids into weakly acidic liquid detergent systems, and how to introduce modified oil ethoxylate sulfonates into weakly acidic liquid detergent systems without reducing system viscosity to fully utilize their low-foaming properties, are urgent problems that need to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a weakly acidic, low-foaming liquid detergent composition. The liquid detergent composition of this invention is weakly acidic, thus exhibiting lower irritation, greater skin-friendliness, and gentler properties on hands. Furthermore, this invention successfully incorporates fatty acids into the weakly acidic system and introduces modified oil ethoxylate sulfonates into the weakly acidic system without reducing its viscosity, thereby giving the weakly acidic liquid detergent composition low-foaming properties and ideal viscosity.

[0007] The specific technical solution of the present invention is as follows: a weakly acidic, low-foaming liquid detergent composition, which is weakly acidic and has a total active ingredient content of 15-30 wt%, comprising the following components: 5-15 wt% modified oleic acid ethoxylate sulfonate, 4-8 wt% fatty alcohol polyether nonionic surfactant, 0.5-2.0 wt% thickener polyethylene glycol difatty acid ester, 0.5-1.5 wt% long-chain fatty acid, alkali neutralizer, 0-10 wt% other additives, and solvent.

[0008] The liquid detergent composition of the present invention is weakly acidic, thus exhibiting lower irritation, greater skin-friendliness, and gentleness on hands. Furthermore, the liquid detergent composition of the present invention successfully introduces fatty acids into the weakly acidic system and introduces modified oil ethoxylate sulfonates into the weakly acidic system without reducing the system viscosity, thereby giving the weakly acidic liquid detergent composition low-foaming properties and ideal viscosity.

[0009] The core components maintaining low-foaming properties in the liquid detergent composition of this invention are modified oil ethoxylate sulfonate, fatty alcohol polyether nonionic surfactant, and a small amount of long-chain fatty acid; the core thickening component is polyethylene glycol difatty acid ester, in which a small amount of long-chain fatty acid has an auxiliary thickening effect. Their mechanisms of action and technical effects are mainly as follows: Regarding low foaming: As can be seen from the molecular structure of modified oil ethoxylate sulfonate (code name SNS-80), under the neutral or weakly alkaline conditions of conventional detergents, the sulfonic acid groups in its molecule exist in aqueous solution in ionized form. There is repulsion between sulfonate molecules. At the same time, since both the polyether portion and the sulfonate group in its molecule are hydrophilic groups, the overall hydrophilic group is relatively large, making this raw material generally difficult to thicken. Therefore, in the prior art, SNS-80 is difficult to use as the main surfactant in large quantities in ordinary neutral or weakly alkaline laundry detergent formulations. Under the weakly acidic conditions of this invention, the SNS-80 sulfonate moiety in the aqueous solution can exist in a protonated form, which reduces the molecular repulsion between hydrophilic ions to a certain extent, thus not significantly reducing the system viscosity. Furthermore, SNS-80 possesses excellent resistance to hard water and calcium soap dispersing power. This invention cleverly utilizes this characteristic of the raw material, combining it with a certain amount of fatty alcohol polyether-type nonionic surfactant to effectively solubilize a certain amount of long-chain fatty acids that are insoluble under weakly acidic conditions, thereby jointly achieving low foaming and easy bleaching of the system (long-chain fatty acids, due to their molecular characteristics, are more suitable for weakly alkaline systems; in weakly acidic systems, they mostly exist in a protonated form, with very limited solubility).

[0010] Regarding thickening: Polyethylene glycol difatty acid esters are known thickeners. Our team discovered that, compared to other conventional thickeners, these compounds can thicken in weakly acidic systems without affecting the low-foaming properties of the product. They are amphiphilic molecules, with the polyether structure being hydrophilic and the long-chain fatty acid structure hydrophobic. Furthermore, both ends of the polyethylene glycol hydroxyl groups can be esterified, resulting in a double-chain structure. The unique structural characteristics of polyethylene glycol difatty acid esters allow them not only to participate in the self-assembly of micelle molecules in solution, forming mixed micelles, but also, thanks to their double-chain structure, to simultaneously anchor two micelle molecules. This increases the length of the aggregates to some extent, and through the cross-stacking of numerous two micelles, a macroscopic increase in overall viscosity is achieved.

[0011] Furthermore, we found that under weakly acidic conditions, a small amount of long-chain fatty acids can further promote the formation of the aforementioned aggregates, thus macroscopically enhancing the thickening efficiency of polyethylene glycol difatty acid esters. In this invention, relying on the solubilizing effect of fatty alcohol polyether nonionic surfactants and SNS-80 in the system, a small amount of long-chain fatty acids is solubilized in the polyether barrier layer of the micelles, playing a role in promoting thickening in the system. Therefore, the thickening effect of polyethylene glycol difatty acid esters and long-chain fatty acids on the system in this invention is pH-dependent, exhibiting a thickening effect only under weakly acidic pH conditions.

[0012] Preferably, the weak acidity is pH = 5.0 to 6.5.

[0013] Within a narrower range of weakly acidic pH (5.0–6.5), polyethylene glycol dicarboxylic acid esters and long-chain fatty acids have a better thickening effect on the system.

[0014] Preferably, the chemical structure of the modified oil ethoxylate sulfonate is as follows:

[0015]

[0016] Among them, the average addition number of EO a+b+c is between 1 and 30, and R is a long-chain aliphatic alkyl group of C8 to C22.

[0017] Further preferred, the modified oil ethoxylated sulfonate is prepared from palm kernel oil, coconut oil, palm oil, and peanut oil through ethoxylation and sulfonation reaction processes. Commercially available industrial raw material grades include, but are not limited to, SNS-80 from Zhongqing Daily Chemical and OXOS-1 from Liaoning Aoke Chemical.

[0018] Preferably, the fatty alcohol polyether type nonionic surfactant has an HLB value of 12 to 18 and can be polymerized from natural fatty alcohol, isomeric fatty alcohol, or natural polyol with ethylene oxide or propylene oxide. Common examples include AEO9, IEO9, and isomeric AEO7. Based on raw material costs, natural alcohol polyoxyethylene ether is preferred.

[0019] Preferably, the long-chain fatty acid has 8 to 22 carbon atoms, and more preferably, includes, but is not limited to, one or more of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, palm kernel oil, and coconut oil.

[0020] Preferably, the thickener, polyethylene glycol difatty acid ester, is prepared by esterification of polyethylene glycol with two molecules of long-chain fatty acid. The polyethylene glycol is selected from PEG400, PEG800, PEG6000, PEG20000, etc., and the long-chain fatty acid is a saturated or unsaturated natural fatty acid with a carbon chain ≥16. Commonly available commercially available polyethylene glycol difatty acid ester raw materials, such as polyethylene glycol 6000 distearate, can be preferred.

[0021] Preferably, the alkali neutralizing agent mainly functions to neutralize excess acidic substances in the system, including but not limited to one or more of KOH, K2CO3, NaOH, and Na2CO3.

[0022] Preferably, the weakly acidic, low-foaming liquid detergent composition contains virtually no sodium chloride, sodium sulfate, potassium chloride, or other salt thickeners, and the total amount of inorganic salts should be ≤0.4%.

[0023] This invention reveals that the counterions introduced by excessive inorganic salts in the formulation can compress the double-layer interaction, potentially reducing the solubility space of the barrier layer and weakening its solubility, thus affecting the stability of long-chain fatty acids in weakly acidic systems. Furthermore, testing showed that the system of this invention differs from conventional liquid detergent systems; thickening the formulation cannot be achieved by adding inorganic salts. Adding additional inorganic salts in the tests resulted in a decrease in the overall viscosity and stability of the formulation.

[0024] Preferably, the other additives include one or more of low-foaming surfactants and functional additives.

[0025] Preferably, the low-foaming surfactant includes, but is not limited to, one or more of the following: oleic acid ethoxylates, fatty acid methyl ester ethoxylates, alkyl glycosides, N-acyl amino acid salts, and alkylbenzene sulfonates.

[0026] Preferably, the efficacy additives include, but are not limited to, one or more of chelating agents, preservatives, enzyme preparations, brightening agents, and color-protecting agents.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) The liquid detergent composition of the present invention is weakly acidic, and therefore has the characteristics of being less irritating, more skin-friendly, and gentle on hands.

[0029] (2) This invention uses modified oil ethoxylate sulfonates in combination with a certain amount of fatty alcohol polyether nonionic surfactants, which significantly improves the solubilizing ability of the system for long-chain fatty acids, making it possible to use long-chain fatty acids in weak acid detergents. At the same time, this invention also utilizes the low-foaming characteristics of long-chain fatty acids and modified oil ethoxylate sulfonates, and by selecting the best surfactant raw materials, it avoids using relatively high-foaming and foam-stabilizing raw materials such as common high-foaming and foam-stabilizing components such as sodium fatty alcohol polyether sulfate (AES), amine oxide, and betaine surfactants, thereby achieving a low-foaming and easy-rinse overall detergent formulation.

[0030] (3) To overcome the low viscosity of modified oil ethoxylate sulfonates, this invention selects polyethylene glycol difatty acid esters as a suitable thickener for this system. It was also found that an appropriate amount of long-chain fatty acids can improve the thickening efficiency of such thickeners under weakly acidic conditions, enabling effective thickening at lower addition levels. This, in turn, improves the economic efficiency of the formulation while maintaining the viscosity of the system. Attached Figure Description

[0031] Figure 1 These are comparative photographs showing the hand-washing and easy-rinsing performance tests of the samples in Example 11 and Comparative Example 13 of this invention. Detailed Implementation

[0032] The following examples further illustrate the present invention, but the scope of protection of the present invention is not limited thereto.

[0033] The technical terms and techniques used in this invention have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, all reagents, raw materials, and equipment used in this invention are commonly used reagents, raw materials, and equipment as understood by those skilled in the art, and are commercially available.

[0034] General Implementation Examples

[0035] A weakly acidic, low-foaming liquid detergent composition, which is weakly acidic (preferably pH 5.0-6.5) and has a total active ingredient content of 15-30 wt%, comprising the following components: 5-15 wt% modified oil ethoxylate sulfonate, 4-8 wt% fatty alcohol polyether nonionic surfactant, 0.5-2.0 wt% thickener polyethylene glycol difatty acid ester, 0.5-1.5 wt% long-chain fatty acid, alkali neutralizer, 0-10 wt% other additives, and solvent.

[0036] As a preferred option, the chemical structure of the modified oil ethoxylate sulfonate is as follows:

[0037]

[0038] The average addition number of EO, a+b+c, is between 1 and 30, and R is a long-chain aliphatic alkyl group of C8 to C22. Further preferred, the modified oil ethoxylate sulfonate can be prepared from natural animal and vegetable oils such as palm kernel oil, coconut oil, palm oil, and peanut oil through ethoxylation and sulfonation processes. Commercially available industrial raw material grades include, but are not limited to, SNS-80 from Zhongqing Daily Chemical and OXOS-1 from Liaoning Aoke Chemical.

[0039] Preferably, the fatty alcohol polyether type nonionic surfactant has an HLB value of 12 to 18 and can be polymerized from natural fatty alcohol, isomeric fatty alcohol, or natural polyol with ethylene oxide or propylene oxide. Common examples include AEO9, IEO9, and isomeric AEO7. Based on the cost of raw materials, natural alcohol polyoxyethylene ether is preferred.

[0040] Preferably, the long-chain fatty acids are selected from one or more of the following natural fatty acids: lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, etc., or they can be mixed fatty acids from natural sources, such as arachidic acid, palm kernel oil, coconut oil, etc.

[0041] Preferably, the thickener, polyethylene glycol difatty acid ester, is prepared by esterification of polyethylene glycol with two molecules of long-chain fatty acids; the polyethylene glycol is selected from PEG400, PEG800, PEG6000, PEG20000, etc., and the long-chain fatty acid is a saturated or unsaturated natural fatty acid with a carbon chain ≥16. Commonly available commercially available polyethylene glycol difatty acid ester raw materials, such as polyethylene glycol 6000 distearate, can be preferred.

[0042] Preferably, the alkali neutralizer mainly functions to neutralize excess acidic substances in the system, including but not limited to one or more of KOH, K2CO3, NaOH, and Na2CO3; and the weak acid low-foaming liquid detergent composition of the present invention is basically free of thickeners such as sodium chloride, sodium sulfate, and potassium chloride, and the total amount of inorganic salts should be ≤0.4%.

[0043] Preferably, other additives include one or more of low-foaming surfactants and functional additives. Preferably, the low-foaming surfactants include, but are not limited to, one or more of oil ethoxylates, fatty acid methyl ester ethoxylates, alkyl glycosides, N-acyl amino acid salts, and alkylbenzene sulfonates. Functional additives include, but are not limited to, one or more of chelating agents, preservatives, enzyme preparations, brightening agents, and color-protecting agents. Specific Implementation

[0045] All raw materials used in this invention are commercially available industrial products. Unless otherwise specified, the surfactant raw materials in the following embodiments and comparative formulations of this invention are all purified.

[0046] SNS-80: Modified grease ethoxylate sodium sulfonate;

[0047] OXOS-1: Modified ester ethoxylate sodium sulfonate;

[0048] DM638: Polyethylene glycol distearate.

[0049] Table 1: Formulations (content / wt%) of Examples 1-4 and Comparative Examples 1-2

[0050] Group Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 liquid alkali 1.0 1.0 1.0 1.0 1.0 1.0 SNS-80 5 10 15 / 4 16 OXOS-1 / / / 10 / / AEO9 5 5 5 5 5 5 Coconut acid 1.0 1.0 1.0 1.0 1.0 1.0 APG1214 4 4 5 4 4 4 DM638 0.8 1.0 2.0 1.0 0.8 2.0 GLDA-4Na 0.5 0.5 0.5 0.5 0.5 0.5 Citric acid / liquid alkali Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Blue pigment 0.001 0.001 0.001 0.001 0.001 0.001 essence 0.3 0.3 0.3 0.3 0.3 0.3 protease 0.2 0.2 0.2 0.2 0.2 0.2 Kathon 0.15 0.15 0.15 0.15 0.15 0.15 Deionized water margin margin margin margin margin margin pH (stock solution) 5.0 5.5 6.0 5.5 6.0 6.0 Viscosity / mPa.s 437 526 336 660 420 135 Total active ingredients / % 15.8 21.0 28.0 21.0 14.8 28 -5℃ stability √ √ √ √ × √

[0051] Table 1 examines the effect of the dosage of modified oil ethoxylate sodium sulfonate (SNS-80) on the stability of weakly acidic formulations. The results show that when the dosage of SNS-80 is too low, such as 4% in Comparative Example 1, the low-temperature stability of the formulation is poor, exhibiting precipitation at -5°C. Conversely, when the content of SNS-80 is too high, such as 16% in Comparative Example 2, even with the thickener DM638 dosage increased to 2%, effective thickening is still not achieved, with a viscosity of only 135 mPa·s. Therefore, the preferred range for modified oil ethoxylate sodium sulfonate is 5–15%. In Example 4, compared to Example 2, SNS-80 was replaced with OXOS-1 from AOK Chemical. The performance of both was comparable, with only a slightly higher viscosity, indicating that commercially available modified oil ethoxylate sulfonates have similar properties and can be used in weakly acidic detergent products.

[0052] Table 2: Formulations (content / wt%) of Examples 5-7 and Comparative Examples 3-5

[0053] Group Example 5 Example 6 Example 7 Comparative Example 3 Comparative Example 4 Comparative Example 5 KOH 0.5 0.5 0.5 0.5 0.5 0.5 SNS-80 10 10 10 10 10 10 AEO9 4 6 8 0 3 9 Coconut acid 1.0 1.0 1.0 1.0 1.0 1.0 Citric acid 0.8 0.8 0.8 0.8 0.8 0.8 DM638 0.8 0.8 0.8 0.8 0.8 2.0 GLDA-4Na 0.5 0.5 0.5 0.5 0.5 0.5 Citric acid / liquid alkali Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Blue pigment 0.001 0.001 0.001 0.001 0.001 0.001 essence 0.3 0.3 0.3 0.3 0.3 0.3 protease 0.2 0.2 0.2 0.2 0.2 0.2 Kathon 0.15 0.15 0.15 0.15 0.15 0.15 Deionized water margin margin margin margin margin margin pH (stock solution) 6.0 6.0 6.0 6.0 6.0 6.0 Viscosity / mPa.s 506 456 389 60 588 136 -5℃ stability √ √ √ Room temperature turbidity × × √

[0054] Table 2 examines the effect of the role and content of fatty alcohol polyoxyethylene ether nonionic surfactants on the formulation of weakly acidic laundry detergent. Comparing the low-temperature freeze resistance and viscosity of Examples 5, 6, and 7 with Comparative Examples 3, 4, and 5, it is evident that the content of AEO9 affects the stability of the formulation. When the content is too low, the fatty acids in the formulation cannot be effectively solubilized, resulting in turbidity at room temperature or precipitation at low temperature. Similar to SNS-80, an excessively high content of AEO9 leads to difficulties in thickening. Therefore, the preferred content of fatty alcohol polyoxyethylene ether nonionic surfactants is 4–8%.

[0055] Table 3: Extended formulation and test results of Example 6

[0056]

[0057] Table 3 extends the use of the fatty alcohol polyether nonionic surfactant in Example 6 to other nonionic surfactants (other properties remain unchanged) as thickeners. Tests revealed that the polyether segment length and HLB value of the nonionic surfactant have a certain impact on the low-temperature stability of the system. Specifically, if the polyether segment is too short and the molecule is relatively lipophilic, the low-temperature stability is poor, resulting in easy precipitation at -5°C (as in Comparative Example 6). Similarly, in Comparative Example 7, PEG400, with an HLB value of 20 and completely hydrophilic molecules, also fails to effectively solubilize the system and achieve low-temperature stability. Therefore, conservatively estimated, the HLB value of the fatty alcohol polyether nonionic surfactant used should be in the range of 12–18.

[0058] Table 4: Formulations (content / wt%) of Examples 8-10 and Comparative Examples 8-10

[0059]

[0060] With other components kept consistent, Table 4 examines the effect of long-chain fatty acid content on the formulation of a weakly acidic detergent. It can be observed that the viscosity of the solution increases with the increase of long-chain fatty acid content. Surprisingly, when no long-chain fatty acids are present in the system, such as in Comparative Example 8, the viscosity is only 60 mPa·s, while in Comparative Example 9, after adding 0.4% coconut oil acid, the viscosity increases by approximately 4.5 times. This shows that long-chain fatty acids not only play a defoaming role in the system but also, to some extent, improve the thickening efficiency of DM638 when combined with it. Looking at Examples 8, 9, and 10, as well as Comparative Examples 8, 9, and 10, it is clear that if the long-chain fatty acid content is too low, such as in Comparative Example 9 (0.4%), the defoaming effect is too poor; while if the long-chain fatty acid content is too high, such as in Comparative Example 10, the low-temperature stability of the formulation is too poor, resulting in failure to meet low-temperature standards. Therefore, the preferred long-chain fatty acid content should be approximately in the range of 0.5% to 1.5%.

[0061] Since the hydrophilic carboxylic acid group of long-chain fatty acids is a weak acid, it will ionize or hydrolyze in aqueous solution with changes in solution pH. Therefore, the content of protonated long-chain fatty acids in the solution may be different under different pH conditions, which may affect the overall viscosity of the system. Therefore, the relationship between the viscosity of the formulation and pH under different pH conditions was investigated, as shown in Table 5.

[0062] Table 5: Expanded formulation and test results of Example 10

[0063] Group Example 10 Example 10-1 Example 10-2 Example 10-3 Comparative Example 11 Comparative Example 12 pH value (stock solution) 5.0 5.5 6.0 6.5 4.8 7.0 Viscosity / mPa.s 426 433 418 323 416 124 -5℃ stability √ √ √ √ × √

[0064] As shown in Table 5, the solution is relatively acidic below pH 6.0, resulting in most long-chain fatty acids existing in protonated form, thus the overall viscosity difference is not significant. However, with further increases in pH, reaching 6.5 and 7.0, a significant decrease in viscosity is observed for the same formulation. This is mainly because the protonated long-chain fatty acids in the solution phase are converted into ionized long-chain fatty acids, thereby affecting the thickening efficiency of polyethylene glycol ether distearate. Comparing the examples and comparative examples in Table 5, a suitable weakly acidic formulation with a pH range of 5.0–6.5 can be roughly obtained.

[0065] Table 6: Effect of Inorganic Salts on Example 11

[0066] Refined salt content / % 0 0.2 0.4 0.6 0.8 1.0 Viscosity / mPa.s 446 433 378 323 288 265 -5℃ stability √ √ √ × × Room temperature turbidity

[0067] Table 6 shows the formulation structure based on Example 11, with the addition of refined salt in the hope of increasing the viscosity of the formulation. However, unexpectedly, the viscosity of the formulation decreased after adding salt, and the stability at -5°C also decreased after a certain amount of salt was added. After comprehensive analysis, the inventors believe that this may be because most of the coconut oil acid in this system is dissolved through solubilization, and the addition of excessive salt not only reduces the solubility of the anionic surfactant in the system but also reduces the solubilizing ability, macroscopically manifesting as a decrease in viscosity and stability.

[0068] Table 7 examines the feasibility of using other surfactant raw materials in small quantities in weak acid formulations. Analysis of Examples 11-14 shows that adding small amounts of surfactant raw materials such as FMEE, SOE-N-60, sodium lauroyl glutamate, and alkylbenzene sulfonic acid does not significantly affect the foaming performance of the weak acid detergent formulation. However, as shown in Comparative Examples 13-15, if raw materials such as AES, amine oxide, and LAB-35 are added to the formulation, the foaming performance will significantly increase and the rinsing ease will decrease because AES itself has high foaming properties and poor low-temperature stability, while amine oxide and LAB-35 act as thickeners and foam stabilizers. Therefore, adding small amounts of other green, low-foaming raw materials does not affect the performance of the main weak acid detergent composition, but raw materials with excessively high foaming properties or good foam stabilization should not be introduced.

[0069] Table 7: Expanding List of Other Surfactant Raw Materials

[0070]

[0071]

[0072] Two samples were randomly selected for hand washing tests, and the results are as follows: Figure 1 As shown. Figure 1 Photos show the hand-washing and rinsing performance test results (test method: concentration 4g / 2L, tap water at 25℃, 60g towel, wrung out to three times the towel's weight each time, rubbed 20 times, and then photographed). The results show that Example 11, which uses the solution of this invention, has significantly less foam and better rinsing performance compared to Comparative Example 13.

[0073] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A weakly acidic, low-foaming liquid detergent composition, characterized in that: It is weakly acidic, with a pH of 5.0 to 6.5, and a total active ingredient content of 15 to 30 wt%. The liquid detergent composition includes the following components: Modified oil ethoxylate sulfonate 5~15wt%, 4-8 wt% of fatty alcohol polyether nonionic surfactants with HLB values ​​of 12-18 Thickener: polyethylene glycol difatty acid ester 0.5~2.0wt%. 0.5–1.5 wt% of long-chain fatty acids with C8–C22 carbon atoms. Alkali neutralizer Other additives 0~10wt%, Solvent, Total inorganic salt content ≤0.4wt%; It does not contain AES surfactant, amine oxide surfactant, or LAB-35 surfactant; The chemical structure of the modified oil ethoxylate sulfonate is as follows: ； Where a+b+c=1~30, and R is a long-chain aliphatic alkyl group of C8~C22.

2. The weak acid low-foaming liquid detergent composition as described in claim 1, characterized in that: The fatty alcohol polyether type nonionic surfactant is a natural alcohol polyoxyethylene ether.

3. The weak acid low-foaming liquid detergent composition according to claim 1, characterized in that: The long-chain fatty acids include one or more of the following: lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, palm kernel oil, and coconut oil.

4. The weak acid low-foaming liquid detergent composition according to claim 1, characterized in that: The thickener, polyethylene glycol difatty acid ester, is prepared by esterification of polyethylene glycol with two molecules of long-chain fatty acids.

5. The weak acid low-foaming liquid detergent composition as described in claim 4, characterized in that: In the esterification reaction, polyethylene glycol is selected from PEG400, PEG800, PEG6000, and PEG20000; the long-chain fatty acid is a saturated or unsaturated natural fatty acid with a carbon chain ≥16.

6. The weak acid low-foaming liquid detergent composition according to claim 1, characterized in that: The other additives include one or more of low-foaming surfactants and functional additives.

7. The weak acid low-foaming liquid detergent composition as described in claim 6, characterized in that: The low-foaming surfactant includes one or more of the following: oleoester ethoxylates, fatty acid methyl ester ethoxylates, alkyl glycosides, N-acyl amino acid salts, and alkylbenzene sulfonates.

8. The weak acid low-foaming liquid detergent composition as described in claim 6, characterized in that: The efficacy additives include one or more of the following: chelating agents, preservatives, enzyme preparations, color enhancers, and color protectants.

9. The weak acid low-foaming liquid detergent composition according to claim 1, characterized in that: The alkali neutralizing agent includes one or more of KOH, K2CO3, NaOH, and Na2CO3.

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