A weak acid non-alcohol solvent type concentrated detergent and a preparation method thereof

Abstract

This invention relates to the field of detergents, and discloses a weakly acidic, alcohol-free solvent-based concentrated detergent and its preparation method. The concentrated detergent has a pH of 5.0-7.0 and comprises 40-70 wt% active ingredient and the remainder water. The active ingredient includes: 15-40% modified oil ethoxylate sulfonate, 15-40% polyether nonionic surfactant, 2-5% fatty acid, 2-8% polyethylene glycol difatty acid ester, and 0.1-6% inorganic base neutralizer. This invention uses modified oil ethoxylate sulfonate combined with polyether nonionic surfactant to achieve high concentration in an alcohol-free solvent without the need for solubilizers or stabilizers. To avoid the introduction of large amounts of inorganic salts, this invention introduces polyethylene glycol difatty acid ester and an appropriate amount of fatty acid as thickeners, which have good thickening effects in high-water-content weakly acidic systems, thus maintaining a high viscosity even after high dilution.

Description

Technical Field

[0001] This invention relates to the field of detergents, and more particularly to a concentrated detergent of weak acid and alcohol-free solvent that can maintain high viscosity with high dilution, and its preparation method. Background Technology

[0002] In recent years, "concentrated liquid" type concentrated detergent products have appeared on the domestic market. These are highly concentrated detergent systems, requiring consumers to dilute them themselves to achieve the concentration of regular laundry detergent. This design allows consumers to use the concentrated product as they would with regular laundry detergent, directly experience its concentrated properties, and fully utilize its environmentally friendly advantages. Therefore, concentrated products using this technology have significant market potential.

[0003] However, the "high concentration" or "concentration" of detergents presents significant technical challenges. For instance, common surfactants such as AES and AEO9 have certain gelation regions, thus limiting the selection of raw materials for traditional concentrated detergents. Furthermore, conventional surfactants, due to their solubility limitations, are difficult to concentrate at high concentrations, necessitating the use of alcohols such as propylene glycol and glycerin as alcohol solubilizers to ensure the stability of the concentrated formula during storage. However, the use of alcohols significantly reduces the apparent viscosity of the product (before dilution), making it difficult for consumers to subjectively perceive the concentrated characteristics of the product.

[0004] In existing technologies, dilution and thickening of concentrated detergent products is achievable. For example, patent CN115368978A uses an alkanolamide surfactant and salt in combination, and with the combined action of a certain amount of alcohol solvent and organic amine neutralizer, it can achieve a dilution and thickening of up to 6 times for concentrated samples; patent CN107922547A discloses a detergent composition composed of hydroxyalkyl methyl cellulose ether, acrylate (fatty acid) ester polymer and surfactant, which can maintain a high viscosity even after dilution by 2 or 3 times; and patent CN... Patent 101563443A discloses a dishwashing detergent product with approximately 30% active ingredients formed from surfactants such as AES, sulfonic acid, and betaine. After dilution by 2 times, the viscosity increases instead of decreasing, demonstrating dilution and thickening properties. Another example is a highly concentrated detergent containing 20-35% comb-shaped polyether and 1.5-6.0% sodium chloride, prepared by combining conventional surfactants such as alkylbenzene sulfonic acid, FMEE, AOS, and isomeric alcohol ethers with a comb-shaped polyether polymer with a specific structure and sodium chloride. The highly concentrated detergent still has a high viscosity after dilution by 4 times.

[0005] A careful analysis of existing patents reveals that 2-3 times concentration is common, while higher concentrations, such as 4-5 times, are practically difficult to achieve. Higher concentration systems typically require the use of alcohol solubilizers and a certain amount of inorganic salts to maintain viscosity after high dilution. For example, CN115368978A and CN107446711A both use alcohol solvents such as propylene glycol as co-solvents, and also use a certain amount of inorganic salts to increase viscosity after dilution. As mentioned earlier, the use of alcohol solvents significantly reduces the apparent viscosity of the concentrated detergent before dilution, making it difficult for consumers to subjectively perceive the product's concentrated characteristics. Inorganic salts have different effects on different systems; at low water content, their solubility is limited, sometimes causing the concentrated system to gel or separate, reducing stability. Furthermore, patent CN115368978A uses organic amines as solubilizers or stabilizers for surfactants, and the use of organic amines makes the product susceptible to yellowing due to aging after high temperature or light exposure.

[0006] In addition, in existing research, modified oleoethoxylated sulfonates are widely recommended for use in concentrated detergent systems such as pods where viscosity adjustment is not required due to their water miscibility and viscosity-reducing properties. For example, patent CN111139144A discloses a low-temperature easy-rinse ultra-concentrated liquid detergent and its preparation method, utilizing the good solubility, viscosity-reducing, and easy-rinse properties of modified oleoethoxylated sulfonates (SNS-80); another example is patent CN110331049A, which utilizes SNS-80 combined with viscous alkyl glycosides to achieve good low-temperature fluidity of the raw materials and facilitate production operations; yet another example is patent CN109181894A, which discloses an ultra-concentrated detergent containing oleoethoxylated sulfonates, which has strong detergency, low viscosity, and excellent high and low temperature fluidity.

[0007] However, due to the viscosity-reducing properties of modified oil ethoxylate sulfonates, the viscosity of concentrated systems containing them is significantly reduced after dilution. Therefore, there is currently no precedent for using them as a main raw material in diluted and thickened concentrated slurry products. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a concentrated detergent in a weakly acidic, alcohol-free solvent that maintains high viscosity even after high dilution, and its preparation method. On one hand, this invention uses modified oil ethoxylate sulfonate as the main surfactant, combined with a polyether-type nonionic surfactant, enabling high concentration in an alcohol-free solvent without the need for solubilizers or stabilizers such as organic amines. Therefore, the concentrated detergent of this invention exhibits good color performance, with minimal yellowing after high-temperature or light-induced aging. On the other hand, to avoid the introduction of large amounts of inorganic salts, this invention introduces polyethylene glycol difatty acid esters and an appropriate amount of fatty acids as thickeners. These have excellent thickening effects on modified oil ethoxylate sulfonate in a high-water-content, weakly acidic system. Therefore, the concentrated detergent of this invention maintains a high viscosity even after high dilution.

[0009] The specific technical solution of this invention is as follows:

[0010] In a first aspect, the present invention provides a concentrated detergent of weak acid and alcohol-free solvent that can maintain high viscosity with high dilution, pH=5.0~7.0, comprising 40~70wt% active ingredient and the balance being water solvent.

[0011] Based on the total amount of weak acid alcohol-free solvent-based concentrated detergent, the active ingredients include the following raw materials in the following mass percentages: 15-40% modified oil ethoxylate sulfonate, 15-40% polyether nonionic surfactant, 2-5% fatty acid, 2-8% polyethylene glycol difatty acid ester, 0.1-6% inorganic alkali neutralizer, and 0-15% other additives.

[0012] Unlike traditional dilution-thickening concentrated detergent systems, this invention utilizes the non-gelation region and viscosity-reducing properties of modified oil ethoxylate sulfonates as the main surfactant, combined with a certain amount of polyether-type nonionic surfactants, to achieve high concentration of the overall formula under alcohol-free solvent conditions. At the same time, this invention does not require the use of organic amines or other substances as solubilizers or stabilizers for the surfactants in the concentrated system. Therefore, the concentrated detergent of this invention has better color performance, and the yellowing of the product after high-temperature aging or light aging is relatively slight.

[0013] Furthermore, to overcome the low viscosity drawback of concentrated systems containing modified oil ethoxylate sulfonates after dilution, and to achieve the goal of maintaining high viscosity of concentrated detergents even after high dilution, this invention introduces polyethylene glycol difatty acid esters as thickeners into the system. This invention has discovered that polyethylene glycol difatty acid esters, a traditional thickener, exhibit unique thickening capabilities in the specific systems of this invention. Its thickening efficiency appears to be related to the water content of the system. In highly concentrated, low-water systems (before dilution), its thickening efficiency is poor, showing dissolution in surfactant-concentrated systems; however, in weakly acidic systems with high water content (after dilution), it can rapidly respond to the fatty acids in the system, achieving high viscosity of the diluted sample without relying on conventional electrolytes such as sodium chloride. In other words, we found that polyethylene glycol difatty acid esters can only thicken modified oil ethoxylate sulfonates, which are difficult to thicken with conventional thickeners, in weakly acidic systems with high water content when combined with a small amount of fatty acids; therefore, the concentrated detergent of this invention can maintain high viscosity even after dilution. Coincidentally, this invention also discovered that polyethylene glycol difatty acid esters can be dissolved in large quantities in high-content polyether nonionic surfactants. Furthermore, because of their low thickening efficiency in low-water-content concentrated systems, it is possible to increase their addition amount in concentrated systems. Under normal circumstances, such thickeners cannot be used in concentrated systems.

[0014] To further improve the thickening effect of the concentrated system after dilution, fatty acids are introduced into the system. This is because we have found that under weakly acidic conditions, a small amount of fatty acid macroscopically enhances the thickening efficiency of polyethylene glycol difatty acid esters. The mechanism is as follows: polyethylene glycol difatty acid esters are amphiphilic molecules; their polyether structure is hydrophilic, while the long-chain fatty acid structure is hydrophobic. Simultaneously, the hydroxyl groups at both ends of polyethylene glycol can be esterified, resulting in a double-chain structure. The unique structural characteristics of polyethylene glycol difatty acid esters enable them not only to participate in the self-assembly of small micelle molecules in the solution phase, 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 thus, through the cross-stacking of numerous two micelles, a macroscopic increase in overall viscosity is achieved. Furthermore, we have found that under weakly acidic conditions, a small amount of fatty acid can further promote the formation of these aggregates. In this invention, relying on the solubilizing effect of polyether-type nonionic surfactants and modified oil ethoxylate sulfonates in the system, a small amount of fatty acids can be solubilized in the polyether barrier layer of the micelles (fatty acids usually exist in a protonated form in weakly acidic systems and are difficult to dissolve), thus promoting thickening in the system. Therefore, the thickening effect of polyethylene glycol difatty acid esters and fatty acids in this invention is pH-dependent, exhibiting a thickening effect only under weakly acidic pH conditions. Therefore, the concentrated system of this invention does not require the use of conventional inorganic salts, such as sodium chloride, sodium sulfate, and potassium chloride, for thickening assistance, but instead relies on a small amount of fatty acids in the system. In a weakly acidic environment, the selection of fatty acids plays an important role in maintaining the viscosity of the system.

[0015] Preferably, the weakly acidic alcohol-free solvent-based concentrated detergent has a pH of 5.0-6.5 and includes 40-70 wt% active ingredient and the balance being water solvent.

[0016] Based on the total amount of weak acid alcohol-free solvent-based concentrated detergent, the active ingredients include the following raw materials in the following mass percentages: 20-40% modified oil ethoxylate sulfonate, 15-30% polyether nonionic surfactant, 2-4% fatty acid, 2-6% polyethylene glycol difatty acid ester, 0.1-3% inorganic alkali neutralizer, and 0-15% other additives.

[0017] Preferably, the mass ratio of the polyether-type nonionic surfactant to polyethylene glycol difatty acid ester is greater than 5:1; when the concentrated detergent is diluted 3 to 5 times, the viscosity of the diluted solution increases or remains essentially unchanged.

[0018] Preferably, the modified oil ethoxylated sulfonate is obtained by ethoxylation and sulfonation of natural animal and vegetable oils such as palm kernel oil, coconut oil, palm oil, and peanut oil. 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.

[0019] Further preferably, the chemical structure of the modified oil ethoxylate sulfonate is as follows:

[0020] ;

[0021] Where a+b+c=1~30, and R is a long-chain aliphatic alkyl group of C8~C22.

[0022] Preferably, the polyether-type nonionic surfactant is polymerized from natural fatty alcohol, isomeric fatty alcohol, or natural polyol with ethylene oxide or propylene oxide; common ones include AEO9, IEO9, isomeric AEO7, Tween 20, etc., and natural alcohol polyoxyethylene ether is preferred based on raw material cost.

[0023] Further optimization is achieved by using polyether-type nonionic surfactants with HLB values ​​in the range of 12 to 18.

[0024] Preferably, the fatty acid is a natural fatty acid or a mixture of fatty acids from natural sources; the natural fatty acid is selected from lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, etc.; the natural mixed fatty acid is selected from arachidic acid, palm kernel oil, coconut oil acid, etc.

[0025] Further optimization yields fatty acids with a carbon number of C8 to C22.

[0026] Preferably, the polyethylene glycol difatty acid ester is synthesized by esterification reaction of polyethylene glycol of different molecular weights with two molecules of saturated or unsaturated natural fatty acids with carbon chains ≥16.

[0027] Further preferably, the polyethylene glycol is selected from PEG400, PEG800, PEG6000, PEG20000, etc., and the long-chain fatty acids are selected from common commercially available polyethylene glycol difatty acid esters, such as polyethylene glycol 6000 distearate.

[0028] Preferably, the inorganic base neutralizing agent includes, but is not limited to, one or more of KOH, K2CO3, NaOH, and Na2CO3.

[0029] The main function of inorganic base neutralizers is to neutralize excess acidic substances in a system.

[0030] Preferably, the other additives include other surfactants and / or functional additives. Other surfactants include, but are not limited to, one or more of commercially available 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 preservatives, enzyme preparations, brightening agents, and color-protecting agents.

[0031] Secondly, the present invention provides a method for preparing a concentrated detergent, comprising the following steps:

[0032] 1) Add polyether-type nonionic surfactant to the container and heat it; then add polyethylene glycol difatty acid ester and melt and completely dissolve it;

[0033] 2) Add the modified oil ethoxylate sulfonate and water sequentially, and disperse evenly;

[0034] 3) Add inorganic base neutralizer, fatty acid and other auxiliaries (if any) in sequence;

[0035] 4) After stirring and dispersing, adjust the pH of the system to the target pH;

[0036] 5) Finally, add enzyme preparation and fragrance (if any), stir well, and add enough volatile water to obtain a weak acid alcohol-free solvent-based concentrated detergent.

[0037] Preferably, in step (1), the temperature is raised to 40~60℃.

[0038] Preferably, in step (1), the polyethylene glycol difatty acid ester is in powder or flake form.

[0039] Compared with the prior art, the present invention has the following technical effects:

[0040] (1) Unlike traditional dilution and thickening concentrated detergent systems, this invention utilizes the non-gelation region and viscosity-reducing properties of modified oil ethoxylate sulfonate as the main surfactant, combined with a certain amount of polyether nonionic surfactant, which enables the overall formula to achieve high concentration under alcohol-free solvent conditions; at the same time, there is no need to add organic amines or other substances as solubilizers or stabilizers. Therefore, the concentrated detergent of this invention has better color performance, and the yellowing of the product after high-temperature aging or light aging is relatively slight.

[0041] (2) In this invention, polyethylene glycol difatty acid esters and an appropriate amount of fatty acids are introduced into the system as thickeners. They have almost no thickening effect in highly concentrated, low-water systems (before dilution), but they have a good thickening effect on modified oil ethoxylate sulfonates in weakly acidic systems with high water content (after dilution). Therefore, the concentrated detergent of this invention can overcome the disadvantage of viscosity reduction after dilution following the introduction of modified oil ethoxylate sulfonates, and can still maintain a high viscosity after high dilution. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. The technical terms and methods 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 the invention are commonly used reagents, raw materials, and equipment understood by those skilled in the art and are commercially available.

[0043] General Implementation Examples

[0044] A concentrated detergent with weak acid and alcohol-free solvent that can maintain high viscosity even after high dilution, pH=5.0~7.0 (preferably 5.0-6.5), comprising 40~70wt% active ingredient and the balance being water solvent.

[0045] Based on the total amount of weak acid alcohol-free solvent-based concentrated detergent, the active ingredients include the following raw materials in the following mass percentages: 15-40% (preferably 20-40%) of modified oil ethoxylate sulfonate, 15-40% (preferably 15-30%) of polyether nonionic surfactant, 2-5% (preferably 2-4%) of fatty acid, 2-8% (preferably 2-6%) of polyethylene glycol difatty acid ester, 0.1-6% (preferably 0.1-3%) of inorganic alkali neutralizer, and 0-15% (preferably 0-10%) of other additives.

[0046] Preferably:

[0047] The mass ratio of polyether-type nonionic surfactant to polyethylene glycol difatty acid ester is greater than 5:1; when concentrated detergent is diluted 3 to 5 times, the viscosity of the diluted solution increases or remains basically unchanged.

[0048] Modified oil ethoxylated sulfonates are obtained from natural animal and vegetable oils such as palm kernel oil, coconut oil, palm oil, and peanut oil through ethoxylation and sulfonation reactions. 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. A further preferred chemical structure is:

[0049] ;

[0050] Where a+b+c=1~30, and R is a long-chain aliphatic alkyl group of C8~C22.

[0051] Polyether-type nonionic surfactants are polymerized from natural fatty alcohols, isomeric fatty alcohols, or natural polyols with ethylene oxide or propylene oxide. Common examples include AEO9, IEO9, isomeric AEO7, and Tween 20. Based on raw material costs, natural alcohol polyoxyethylene ethers are preferred. Further preferred options are polyether-type nonionic surfactants with an HLB value in the range of 12 to 18.

[0052] The fatty acids are natural fatty acids or mixed fatty acids from natural sources; natural fatty acids are selected from lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, etc.; natural mixed fatty acids are selected from arachidic acid, palm kernel oil acid, coconut oil acid, etc. Further preferred, the fatty acids have a carbon number of C8 to C22.

[0053] Polyethylene glycol difatty acid esters are synthesized by esterification of polyethylene glycol of different molecular weights with two molecules of saturated or unsaturated natural fatty acids with carbon chains ≥16. Further preferred, the polyethylene glycol is selected from PEG400, PEG800, PEG6000, PEG20000, etc., and the long-chain fatty acid is selected from common commercially available polyethylene glycol difatty acid ester raw materials, such as polyethylene glycol 6000 distearate.

[0054] Inorganic base neutralizing agents include, but are not limited to, one or more of KOH, K2CO3, NaOH, and Na2CO3.

[0055] Other additives include other surfactants and / or functional additives. Other surfactants include, but are not limited to, one or more of the following: commercially available 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 the following: preservatives, enzyme preparations, brightening agents, and color-protecting agents.

[0056] A method for preparing a concentrated detergent includes the following steps:

[0057] 1) Add polyether-type nonionic surfactant to the container and heat to 40~60℃; then add powdered or flake polyethylene glycol difatty acid ester and melt and completely dissolve it;

[0058] 2) Add the modified oil ethoxylate sulfonate and water sequentially, and disperse evenly;

[0059] 3) Add inorganic base neutralizer, fatty acid and other auxiliaries (if any) in sequence;

[0060] 4) After stirring and dispersing, adjust the pH of the system to the target pH;

[0061] 5) Finally, add enzyme preparation and fragrance (if any), stir well, and add enough volatile water to obtain a weak acid alcohol-free solvent-based concentrated detergent.

[0062] Specific embodiments and comparative examples

[0063] 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.

[0064] SNS-80, OXOS-1: Modified ester ethoxylate sodium sulfonate;

[0065] DM638: Polyethylene glycol 6000 distearate.

[0066] Table 1: Formulations (content / wt%) of Examples 1-4 and Comparative Examples 1-3

[0067] Group Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 liquid alkali 1.5 1.5 2.4 1.5 1.5 1.5 1.5 3.6 SNS-80 25 / 15 40 14 20 40 40 OXOS-1 / 25 / / / / / / <![CDATA[AEO9]]> 20 20 40 20 25 41 20 20 Coconut acid 2.5 2.5 4 2.5 2.5 2.5 2.5 6 DM638 3 3 8 4 5 5 5 5 GLDA-4Na 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Citric acid monohydrate / liquid alkali Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH essence 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Deionized water margin margin margin margin margin margin margin margin pH (stock solution) 5.5 5.5 7.0 5.0 6.0 6.0 6.0 6.0 Total active ingredients / % 50.5 50.5 67 66.5 46.5 68.5 67.5 71.0 Original pulp appearance Slightly turbid Slightly turbid cream Slightly turbid gel gel cream cream pulp stability √ √ √ √ √ √ Layered × Layered × Original pulp viscosity / mPa.s 552 643 1200 465 / / / / 3x dilution viscosity / mPa.s 580 742 1480 623 / / / / 5x dilution viscosity / mPa.s 237 245 880 541 / / / /

[0068] The difference between Examples 1 and 2 lies in the use of different brands of modified oil ethoxylate sodium sulfonate (SNS-80 and OXOS-1, respectively). The results show that modified oil ethoxylate sodium sulfonate from different manufacturers has similar properties and can be used as a parallel substitute raw material. Data analysis shows that the concentrated slurry of Examples 1 and 2 can be diluted 3 times while maintaining a certain viscosity, while the viscosity is relatively low after a 5-fold dilution. This is mainly due to the lower activity of the concentrated slurry itself. Furthermore, as shown in Examples 3 and 4, increasing the concentration of the slurry can achieve even higher viscosity retention, such as a 5-fold dilution.

[0069] Comparative Examples 1-4 and Examples 3 and 4 are based on Example 1 with adjustments to the proportions of raw materials. Comparisons show that the ratios of various raw materials significantly affect the stability of the final concentrated slurry. When the SNS-80 content is too low (e.g., Comparative Example 1) or the AEO9 content is too high (e.g., Comparative Example 2), the concentrated slurry exhibits gelation during sample preparation, making sample preparation impossible. This is mainly due to the existence of a gelation zone in the traditional polyether-type nonionic surfactant AEO9. In this invention, the viscosity-reducing properties of SNS-80 are utilized in combination with AEO9 to effectively reduce the range of the gelation zone in the mixed system. Similarly, theoretically, if the SNS-80 content is too high, its viscosity-reducing effect will be too significant, making it difficult to effectively thicken the slurry after dilution. Therefore, the preferred content of SNS-80 and AEO9 is 15-40%.

[0070] Comparative Example 3 increased the amount of DM638 compared to Example 4, and found that the concentrated slurry exhibited stratification during storage. This is mainly because the thickener itself dissolves in the concentrated system through hydrogen bonding between its polyether segments and water or between the polyether segments themselves. Therefore, the stratification phenomenon is related to both the water content and the content of the polyether nonionic surfactant in the system. For example, in Comparative Example 3, the mass ratio of AEO9:DM638 was 4:1, and because its total active ingredient content was high and the water content in the system was low, DM638 could not be effectively dissolved in the system. Therefore, the preferred ratio of polyether nonionic surfactant to polyethylene glycol difatty acid ester should preferably be ≥5:1.

[0071] Comparative Example 4 increased the amount of fatty acids compared to Example 4. As a result, the original slurry was milky white during sample preparation and exhibited stratification during storage. This may be because the system of this invention is weakly acidic, and the fatty acids exist in a protonated form, thus failing to dissolve in the system. Excessive fatty acids can also affect the stability of the slurry after dilution; therefore, the preferred fatty acid content should be <6%.

[0072] Table 2: Expanded formulation and test results of Example 1

[0073] Group Example 1-0 Example 1-1 Examples 1-2 Examples 1-3 Examples 1-4 Examples 1-5 Comparative Example 5 Comparative Example 6 <![CDATA[AEO9]]> 20 / / / / / / / <![CDATA[AEO7]]> / 20 / / / / / / <![CDATA[IEO9]]> / / 20 / / / / / <![CDATA[Isomeric AEO7]]> / / / 20 / / / / XL-80 / / / / 20 / / / Tween-20 / / / / / 20 / / <![CDATA[AEO5]]> / / / / / / 20 / PEG400 / / / / / / / 20 HLB value 14 12 14 13 14 17 11 20 pH (stock solution) 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Original pulp viscosity / mPa.s 533 589 478 389 398 536 602 235 pulp stability √ √ √ √ √ √ Layered × √ 3x dilution viscosity / mPa.s 576 602 556 446 405 555 / 222 3x dilution low temperature stability √ √ √ √ √ √ × ×

[0074] Table 2 extends the use of the polyether-type nonionic surfactants in Examples 1-0 to other nonionic surfactants (others remain unchanged). Tests revealed that the length of the nonionic polyether chain segment and the HLB value of the molecule have a certain impact on the low-temperature stability of the diluted solution. Specifically, if the polyether chain segment is too short and the molecule is relatively lipophilic, the low-temperature stability is poor, manifesting as easy precipitation at -5°C (as in Comparative Example 5). Similarly, in Comparative Example 6, PEG400, with an HLB value of 20 and a completely hydrophilic molecule, also cannot effectively solubilize the system and achieve low-temperature stability. Therefore, conservatively estimated, the HLB value of the polyether-type nonionic surfactant used should be in the range of 12 to 18.

[0075] Table 3: Expanding List of Other Surfactant Raw Materials

[0076] Group Example 5 Example 6 Example 7 Example 8 Comparative Example 7 Comparative Example 8 liquid alkali 1.8 1.8 1.8 1.8 1.8 1.8 SNS-80 30 30 30 30 30 30 <![CDATA[AEO9]]> 20 20 20 20 20 20 Coconut acid 3.0 3.0 3.0 3.0 3.0 3.0 DM638 4 4 4 4 4 4 GLDA-4Na 0.5 0.5 0.5 0.5 0.5 0.5 sulfonic acid 8 / / / / / FMEE / 8 / / / / SOE-N-60 / / 8 / / / Sodium lauroyl glutamate / / / 8 / / AES / / / / 8 / Refined salt / / / / / 1.0 Citric acid monohydrate / liquid alkali Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH 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 Original pulp viscosity / mPa.s 488 420 386 356 / / pulp stability √ √ √ √ × Gel × Gel 5x dilution viscosity / mPa.s 602 504 465 442 / / 5x dilution for low temperature stability √ √ √ √ / /

[0077] Table 3 expands the application of other surfactants in the raw materials. As shown in Examples 5-8, the introduction of small amounts of surfactants such as sulfonic acid, FMEE, SOE-N-60, and sodium lauroyl glutamate into the concentrated slurry does not significantly affect the stability of the concentrated slurry or its viscosity retention after dilution. However, as shown in Comparative Examples 7 and 8, commonly used raw materials in detergent products, such as AES and refined salt, cannot be used. The former, AES, is mainly due to its wide gelation region, making it extremely easy to gel. The latter, refined salt, although a commonly used thickening raw material in detergent products, does not rely on sodium chloride to maintain viscosity after dilution in the concentrated system of this invention. Furthermore, no alcohol solvents or other solubilizing measures are used in the slurry formulation. The addition of refined salt would exacerbate the gelation of active ingredients in the system, thus making it unsuitable for use in this system.

[0078] The preparation process of the concentrated detergent in the above case is as follows:

[0079] (1) Add a polyether-type nonionic surfactant to the production reactor and heat it to 50°C. Then add powdered polyethylene glycol difatty acid ester and melt and completely dissolve it;

[0080] (2) Add the modified oil ethoxylate sulfonate in sequence, followed by the amount of water required in the formula, and disperse it evenly;

[0081] (3) First add the alkali neutralizer in the formula amount, then add fatty acids and / or other surfactants and functional additives (if any) in sequence.

[0082] (4) After stirring and dispersing, adjust the pH of the system to a suitable value with citric acid or liquid alkali;

[0083] (5) Finally, add enzyme preparations, fragrances, etc. (if any), stir evenly, and replenish the volatile water to obtain alcohol-free solvent-based weak acid concentrated detergent.

[0084] The key to this process is that the polyether nonionic surfactant needs to be pre-mixed with modified oil ethoxylate sulfonate before being added to the remaining water in the formulation to fully utilize its viscosity-reducing properties. Simultaneously, the thickener, polyethylene glycol difatty acid ester, requires heating to dissolve; using a polyether nonionic surfactant can accelerate its dissolution rate. Then, when fatty acids or other surfactants are added, gelation that may occur during the mixing process can be effectively reduced.

[0085] 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.

[0086] 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 weak acid, non-alcohol, solvent type concentrated detergent, characterized by: pH=5.0~6.5, comprising 40~70wt% active ingredient and the balance being water solvent; based on the total amount of weakly acidic alcohol-free solvent-based concentrated detergent, the active ingredient comprises the following raw materials by mass percentage: Modified oil ethoxylate sulfonate 15~40%, 15-40% of polyether-type nonionic surfactants with an HLB value of 12-18 Fatty acids with 2-5% of the carbon number (C8-C22) 2-8% polyethylene glycol difatty acid ester Inorganic base neutralizing agent 0.1~6%; The mass ratio of the polyether-type nonionic surfactant to the polyethylene glycol difatty acid ester is greater than 5:1; 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 concentrated detergent according to claim 1, wherein: pH=5.0-6.5, comprising 40-70 wt% active ingredient and the balance being water solvent; based on the total amount of weakly acidic, alcohol-free solvent-based concentrated detergent, the active ingredient comprises the following raw materials by mass percentage: Modified oil ethoxylate sulfonate 20-40%, 15-30% of polyether-type nonionic surfactants with an HLB value of 12-18 Fatty acids with 2-4% of the carbon number (C8-C22) 2-6% polyethylene glycol difatty acid ester Inorganic base neutralizing agent 0.1~3%.

3. The concentrated detergent of claim 1 wherein: The modified oil ethoxylated sulfonate is obtained from natural animal and vegetable oils through ethoxylation and sulfonation reactions.

4. The concentrated detergent of claim 1 wherein: The polyether-type nonionic surfactant is polymerized from natural fatty alcohols, isomeric fatty alcohols, or natural polyols with ethylene oxide or propylene oxide.

5. The concentrated detergent as described in claim 1, characterized in that: The fatty acids are natural fatty acids or mixed fatty acids from natural sources.

6. The concentrated detergent as described in claim 1, characterized in that: The polyethylene glycol difatty acid ester is synthesized by esterification reaction of polyethylene glycol of different molecular weights with saturated or unsaturated natural fatty acids with carbon chains ≥16.

7. The concentrated detergent as described in claim 1, characterized in that: The inorganic base neutralizing agent includes one or more of KOH, K2CO3, NaOH, and Na2CO3.

8. A method for preparing a concentrated detergent as described in any one of claims 1-7, characterized in that: Includes the following steps: 1) Add polyether-type nonionic surfactant to the container and heat it; then add polyethylene glycol difatty acid ester and melt and completely dissolve it; 2) Add the modified oil ethoxylate sulfonate and water sequentially, and disperse evenly; 3) Add inorganic base neutralizing agent sequentially, along with fatty acids with a carbon number of C8 to C22; 4) After stirring and dispersing, adjust the pH of the system to the target pH; 5) Stir well and add enough volatile water to obtain a weak acid alcohol-free solvent-based concentrated detergent.

9. The preparation method according to claim 8, characterized in that: In step 1), the temperature rise is to 40~60℃.

10. The production method according to claim 8, characterized by: In step 1), the polyethylene glycol difatty acid ester is in powder or flake form.

Images