Hard-water-resistant low-foam LAS surfactant and preparation process thereof

Abstract

The invention discloses a hard-water-resistant low-foam LAS surfactant and a preparation process thereof. The cleaning agent comprises the following components in percentage by mass: 30-40% of linear alkylbenzene sulfonate, 10-15% of fatty alcohol-polyoxyethylene ether carboxylate, 8-12% of fatty acid methyl ester ethoxylate sulfonate, 2-5% of an organic silicon polyether defoaming agent, 5-8% of a chelating agent, 3-6% of a cosolvent, a pH regulator for regulating the pH of a system to 7-8.5 and the balance of deionized water, through the synergistic effect of various chelating agents and the surface active component with chelating ability, calcium and magnesium ions in hard water can be effectively chelated, and the influence of the calcium and magnesium ions on the surfactant is remarkably reduced, so that the surfactant can still keep relatively high activity and stability in a hard water environment, and the decontamination effect is good. In hard water with the calcium and magnesium ion concentration of 500 mg / L, the detergency of the surfactant can still be kept at 90% or above. The organic silicon polyether defoaming agent is matched with the low-foam surface active component, so that quick defoaming and effective foam inhibition can be realized, and the foam height is obviously lower than that of the traditional LAS surface active agent.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of surfactants, in particular to a hard-water-resistant low-foam LAS surfactant and a preparation process thereof. BACKGROUND

[0002] LAS surfactants are widely used in detergents, industrial cleaning and other fields due to their good detergency, cost advantage and biodegradability. However, in a hard water environment, the traditional LAS surfactant is easy to combine with calcium and magnesium ions in water to form insoluble salt, which reduces the surface activity and deteriorates the detergency. At the same time, excessive foam will also affect the cleaning efficiency and rinsing effect, increase the consumption of water resources and production cost. To solve these problems, it is of great practical significance to develop a hard-water-resistant low-foam LAS surfactant. At present, although there are some methods to improve the hard-water resistance and low-foam performance of LAS on the market, there are often problems such as imperfect formula, limited performance improvement and complex preparation process, for example, the existing patent CN115895790A (a cationic-anionic surfactant compound cleaning agent and a preparation method) and the existing patent CN111013484B (an alkyl glycoside carboxy betaine type zwitterionic surfactant and a preparation method thereof) all have the above-mentioned problems, which are difficult to meet the growing industrial and living needs. SUMMARY

[0003] The application aims to provide a hard-water-resistant low-foam LAS surfactant and a preparation process thereof to solve the problems mentioned in the background.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme: a hard-water-resistant low-foam LAS surfactant, which contains the following components in mass percentage: 30-40% of linear alkyl benzene sulfonate, 10-15% of fatty alcohol polyoxyethylene ether carboxylate, 8-12% of fatty acid methyl ester ethoxylate sulfonate, 2-5% of silicone polyether defoamer, 5-8% of chelating agent, 3-6% of cosolvent, pH adjusting agent for adjusting the pH of the system to 7-8.5, and the balance of deionized water.

[0005] Preferably, the application contains the following components in mass percentage: 35% of linear alkyl benzene sulfonate, 12% of fatty alcohol polyoxyethylene ether carboxylate, 10% of fatty acid methyl ester ethoxylate sulfonate, 3% of silicone polyether defoamer, 6% of chelating agent, 4% of cosolvent, pH adjusting agent for adjusting the pH of the system to 8, and the balance of deionized water.

[0006] Preferably, the components include the following by mass percentage: linear alkyl benzene sulfonate 32%, fatty alcohol polyoxyethylene ether carboxylate 10%, fatty acid methyl ester ethoxylate sulfonate 8%, silicone polyether defoamer 2%, chelating agent 5%, cosolvent 3%, pH adjuster to adjust the pH of the system to 8, and deionized water in the balance.

[0007] Preferably, the alkyl chain length of the linear alkyl benzene sulfonate is C10-C14, the carbon chain length of the fatty alcohol in the fatty alcohol polyoxyethylene ether carboxylate is C12-C14, and the polyoxyethylene group has a degree of polymerization of 3-5; the carbon chain length of the fatty acid methyl ester in the fatty acid methyl ester ethoxylate sulfonate is C16-C18, and the degree of ethoxylation is 5-7; the silicone polyether defoamer is copolymerized from polydimethylsiloxane and polyether blocks, and the ratio of the two segments is 2:1-3:1.

[0008] Preferably, the chelating agent includes ethylenediaminetetraacetic acid and its salts 40-50%, diethylenetriamine pentaacetic acid and its salts 30-40%, and aminotri(methylene) phosphonic acid 20-30%; the cosolvent is a mixture of propylene glycol and ethylene glycol in a mass ratio of 1:1-2:1.

[0009] Preferably, the polydimethylsiloxane segment of the silicone polyether defoamer has a molecular weight of 1000-3000 Da, and the polyether segment has an EO / PO block structure; the ethylenediaminetetraacetic acid salt in the chelating agent is a sodium or potassium salt, and the diethylenetriamine pentaacetic acid salt is a calcium sodium salt or a magnesium salt; the degree of sulfonation of the fatty acid methyl ester ethoxylate sulfonate is 70-90%, and it has a double sulfonate structure.

[0010] A preparation process of a hard water-resistant low-foam LAS surfactant includes the following steps:

[0011] Step one, pre-mixing: a calculated amount of deionized water is added to a reaction kettle, stirring is started, and the stirring speed is 200-300 r / min; linear alkyl benzene sulfonate, fatty alcohol polyoxyethylene ether carboxylate, and fatty acid methyl ester ethoxylate sulfonate are sequentially added, and stirring is performed for 15-20 min to preliminarily mix and uniformly disperse the components;

[0012] Step two, adding additives: silicone polyether defoamer, chelating agent, and cosolvent are added to the above-mentioned mixed system, and stirring is continued for 20-30 min to ensure that the additives are fully dispersed in the system; during this process, the temperature in the reaction kettle is controlled to be 30-40°C to prevent the silicone polyether defoamer from being disabled due to excessively high temperature;

[0013] Step three, pH adjustment: a pH adjuster, which is sodium hydroxide and citric acid, is used to adjust the pH value of the system to 7-8.5, and the pH adjuster is added while stirring at a stirring speed of 150-200 r / min for 10-15 min;

[0014] Step four, homogenization: the mixed solution is transferred to a homogenizer, and homogenization is carried out under a pressure of 10-20 MPa, and the processing time is 10-15 min;

[0015] Step five, filtration and packaging: the homogenized surfactant solution is filtered through a filter with a pore size of 0.2-0.5 μm to remove impurities and undissolved particles, and then packaged to obtain the finished hard water-resistant low-foam LAS surfactant.

[0016] Preferably, the dissolution temperature of the linear alkyl benzene sulfonate in step one is controlled at 40-50℃; the homogenization in step four adopts a three-stage homogenization process, and the pressure gradient of each stage is 5-10 MPa; the content of particles with a particle size greater than 1 μm in the product after the filtration step in step five is less than 0.1%.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] Through the synergistic effect of various chelating agents and surfactant components with chelating ability, calcium and magnesium ions in hard water can be effectively chelated, and the influence of calcium and magnesium ions on the surfactant can be significantly reduced, so that the surfactant can still maintain high activity and stability in a hard water environment, and the detergency is good. According to tests, the detergency of the surfactant of the present application can still be maintained at more than 90% in hard water with a calcium and magnesium ion concentration of 500 mg / L. The organic silicon polyether defoaming agent and the low-foam surfactant component cooperate with each other to quickly defoam and effectively suppress foam, and the foam height is significantly lower than that of traditional LAS surfactants. During the cleaning process, the foam height can be controlled at 30-50% of that of traditional products, greatly improving the cleaning efficiency and reducing the number of rinsing and water consumption. The reasonable formula design produces a synergistic effect between the components, improves the hard water resistance and low-foam performance, and maintains excellent detergency. In addition, the addition of the cosolvent improves the stability and compatibility of the system, the pH regulator makes the surfactant in the best active state, and the product quality stability and safety are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the preparation process flow chart of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] Please refer toFigure 1 The application provides a hard water resistant low-foam LAS surfactant which comprises the following components in percentage by mass: linear alkyl benzene sulfonate 30-40%, fatty alcohol polyoxyethylene ether carboxylate 10-15%, fatty acid methyl ester ethoxylate sulfonate 8-12%, silicone polyether defoamer 2-5%, chelating agent 5-8%, cosolvent 3-6%, pH regulator for adjusting the pH of the system to 7-8.5, and deionized water in the remainder.

[0022] The alkyl chain length of the linear alkyl benzene sulfonate is C10-C14, the carbon chain length of the fatty alcohol in the fatty alcohol polyoxyethylene ether carboxylate is C12-C14, and the polyoxyethylene group degree of polymerization is 3-5; the carbon chain length of the fatty acid methyl ester in the fatty acid methyl ester ethoxylate sulfonate is C16-C18, and the ethoxylation degree is 5-7; the silicone polyether defoamer is obtained by copolymerization of polydimethylsiloxane and polyether blocks, and the segment ratio of the two is 2:1-3:1.

[0023] The linear alkyl benzene sulfonate (LAS) is used as the main surfactive ingredient to provide basic detergency. In the application, the linear alkyl benzene sulfonate with a carbon chain length of C10-C14 is selected, and the distribution of the alkyl chain is specially screened, so that the LAS has good detergency and provides a basis for subsequent performance optimization;

[0024] The fatty alcohol polyoxyethylene ether carboxylate (AEC) has excellent hard water resistance and low foam characteristics, and can improve the hard water resistance and low foam effect of the surfactant as a whole in cooperation with the LAS;

[0025] The fatty acid methyl ester ethoxylate sulfonate (FMES) not only has good dispersing performance, but also can effectively reduce the surface tension and has strong chelating capacity for calcium and magnesium ions in a hard water environment, thereby further enhancing the hard water resistance of the surfactant;

[0026] The silicone polyether defoamer can quickly reduce the surface tension of foam and realize efficient defoaming and foam suppression through special molecular structure design.

[0027] The chelating agent comprises 40-50% of ethylenediaminetetraacetic acid and salts thereof, 30-40% of diethylenetriamine pentaacetic acid and salts thereof, and 20-30% of amino-tris-methylene phosphonic acid; and the cosolvent is a mixture of propylene glycol and ethylene glycol with a mass ratio of 1:1-2:1.

[0028] The synergistic effect of the multiple chelating agents can more effectively chelate calcium and magnesium ions in hard water, prevent them from reacting with the surfactant, and improve the stability of the surfactant in a hard water environment;

[0029] The cosolvent can improve the compatibility between the components, increase the stability of the surfactant system, and help reduce the viscosity of the surfactant, facilitating production and use;

[0030] The pH regulator is selected from sodium hydroxide and citric acid, which is used to adjust the pH value of the surfactant solution to 7-8.5, so that the surfactant is in the best active state, and the stability and safety of the product are ensured;

[0031] Deionized water is used as the solvent to uniformly disperse the components and form a stable surfactant solution.

[0032] The polydimethylsiloxane segment of the organic silicon polyether defoamer has a molecular weight of 1000-3000 Da, and the polyether segment has an EO / PO block structure; the chelating agent contains ethylenediaminetetraacetate sodium or potassium salt and diethylenetriamine pentaacetate calcium sodium salt or magnesium salt; the sulfonated degree of the fatty acid methyl ester ethoxylate sulfonate is 70-90%, and it has a double sulfonate structure.

[0033] A preparation process of a hard water-resistant low-foam LAS surfactant includes the following steps:

[0034] Step one, pre-mixing: a calculated amount of deionized water is added to a reaction kettle, and stirring is started with a stirring speed of 200-300 r / min; linear alkyl benzene sulfonate, fatty alcohol polyoxyethylene ether carboxylate, and fatty acid methyl ester ethoxylate sulfonate are sequentially added, and stirring is continued for 15-20 min to preliminarily mix the components uniformly; the dissolution temperature of the linear alkyl benzene sulfonate is controlled at 40-50℃;

[0035] Step two, adding an auxiliary agent: the organic silicon polyether defoamer, the chelating agent, and the cosolvent are added to the above-mentioned mixed system, and stirring is continued for 20-30 min to ensure that the auxiliary agents are fully dispersed in the system; during this process, the temperature in the reaction kettle is controlled at 30-40℃ to prevent the organic silicon polyether defoamer from being disabled due to excessively high temperature;

[0036] Step three, pH adjustment: a pH regulator, which is sodium hydroxide and citric acid, is used to adjust the pH value of the system to 7-8.5; the pH regulator is added while stirring, the stirring speed is adjusted to 150-200 r / min, and the stirring time is 10-15 min;

[0037] Step four, homogenization treatment: the mixed solution is transferred to a homogenizer, and homogenization treatment is performed under a pressure of 10-20 MPa for 10-15 min; the homogenization treatment adopts a three-stage homogenization process, and the pressure gradient of each stage is 5-10 MPa;

[0038] Step five, filtration and packaging: the homogenized surfactant solution is filtered through a filter with a pore size of 0.2-0.5 μm to remove impurities and undissolved particles present, and then packaged to obtain the finished hard water resistant low foam LAS surfactant; the content of particles with a particle size greater than 1 μm in the product after the filtration step is less than 0.1%.

[0039] Example one:

[0040] A hard water resistant low foam LAS surfactant, the formula composition is as follows in terms of mass percentage: linear alkyl benzene sulfonate (LAS, C12-C14) 35%, fatty alcohol polyoxyethylene ether carboxylate (AEC, C12-C14, oxyethylene group polymerization degree is 4) 12%, fatty acid methyl ester ethoxylate sulfonate (FMES, C16-C18, ethoxylate degree is 6) 10%, silicone polyether defoamer (polydimethylsiloxane and polyether block copolymer, the ratio is 2.5:1) 3%, chelating agent (EDTA and its salt accounts for 45%, DTPA and its salt accounts for 35%, ATMP accounts for 20%) 6%, cosolvent (mass ratio of propylene glycol and ethylene glycol is 1.5:1) 4%, pH regulator (sodium hydroxide and citric acid) in appropriate amount, deionized water balance.

[0041] The preparation process is as follows:

[0042] A calculated amount of deionized water is added to the reaction kettle, and stirring is started with a stirring speed of 250 r / min. Linear alkyl benzene sulfonate (LAS), fatty alcohol polyoxyethylene ether carboxylate (AEC), and fatty acid methyl ester ethoxylate sulfonate (FMES) are added in sequence, and stirring is continued for 18 min.

[0043] Silicone polyether defoamer, chelating agent, and cosolvent are added, and stirring is continued for 25 min while controlling the temperature in the reaction kettle at 35°C.

[0044] The pH value of the system is adjusted to 8 using a pH regulator, and stirring is continued while adding, with a stirring speed of 180 r / min and a stirring time of 12 min.

[0045] The mixed solution is transferred to a homogenizer, and homogenization is carried out under a pressure of 15 MPa for 12 min.

[0046] The homogenized surfactant solution is filtered through a filter with a pore size of 0.3 μm, and then packaged to obtain the finished hard water resistant low foam LAS surfactant.

[0047] Example two:

[0048] A hard water resistant low-foam LAS surfactant, whose formula composition is as follows in terms of mass percentage: linear alkyl benzene sulfonate (LAS, C10-C13) 32%, fatty alcohol polyoxyethylene ether carboxylate (AEC, C12-C14, oxyethylene group polymerization degree 3) 10%, fatty acid methyl ester ethoxylate sulfonate (FMES, C16-C18, ethoxylation degree 5) 8%, silicone polyether defoamer (polydimethylsiloxane and polyether block copolymer, ratio 2:1) 2%, chelating agent (EDTA and its salt 40%, DTPA and its salt 30%, ATMP 30%) 5%, cosolvent (mass ratio of propylene glycol and ethylene glycol 1:1) 3%, pH regulator (sodium hydroxide and citric acid) appropriate amount, deionized water balance.

[0049] The preparation process is basically the same as that of Example 1, only the specific parameters of each step are appropriately adjusted: the stirring speeds in the premixing and additive adding steps are 200 r / min and 20 min, 150 r / min and 20 min respectively; the stirring speed during pH adjustment is 150 r / min, and the stirring time is 10 min; the homogenization pressure is 10 MPa, and the treatment time is 10 min; the filter with a pore size of 0.2 μm is used for filtration.

[0050] Example Three

[0051] A hard water resistant low-foam LAS surfactant, whose formula composition is as follows in terms of mass percentage: linear alkyl benzene sulfonate (LAS, C13-C14) 38%, fatty alcohol polyoxyethylene ether carboxylate (AEC, C12-C14, oxyethylene group polymerization degree 5) 15%, fatty acid methyl ester ethoxylate sulfonate (FMES, C16-C18, ethoxylation degree 7) 12%, silicone polyether defoamer (polydimethylsiloxane and polyether block copolymer, ratio 3:1) 5%, chelating agent (EDTA and its salt 50%, DTPA and its salt 40%, ATMP 10%) 8%, cosolvent (mass ratio of propylene glycol and ethylene glycol 2:1) 6%, pH regulator (sodium hydroxide and citric acid) appropriate amount, deionized water balance.

[0052] The preparation process is basically the same as that of Example 1, and the stirring speed, pH adjustment time, and homogenization pressure parameters are optimized: the stirring speeds in the premixing and additive adding steps are 300 r / min and 20 min, 200 r / min and 30 min respectively; the stirring speed during pH adjustment is 200 r / min, and the stirring time is 15 min; the homogenization pressure is 20 MPa, and the treatment time is 15 min; the filter with a pore size of 0.5 μm is used for filtration.

[0053] The hard water resistant low-foam LAS surfactants prepared in the above Example One, Example Two and Example Three are subjected to performance testing, and the results are as follows:

[0054]

[0055] It can be seen from the above test data that the hard water resistant and low foam LAS surfactant prepared by the present application is significantly superior to the conventional LAS surfactant in terms of hard water resistance and low foam performance, while maintaining good detergency.

[0056] The present application can effectively chelate calcium and magnesium ions in hard water by the synergistic effect of multiple chelating agents and surfactants with chelating ability, significantly reducing the influence of calcium and magnesium ions on surfactants, so that the surfactants can still maintain high activity and stability in hard water environment, and have good detergency. According to tests, the detergency of the surfactant of the present application can still be maintained at more than 90% in hard water with a calcium and magnesium ion concentration of 500 mg / L. The silicone polyether defoamer and the low foam surfactant component cooperate with each other to quickly defoam and effectively suppress foam, and the foam height is significantly lower than that of conventional LAS surfactants. During the cleaning process, the foam height can be controlled at 30-50% of that of conventional products, greatly improving the cleaning efficiency and reducing the number of rinsing and water consumption. The reasonable formula design produces a synergistic effect between the components, improves the hard water resistance and low foam performance, and maintains excellent detergency. In addition, the addition of the cosolvent improves the stability and compatibility of the system, the pH regulator makes the surfactant in the best active state, and ensures the stability and safety of the product quality.

[0057] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to part of the technical features, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A hard water resistant low foaming LAS surfactant, characterized in that: The invention comprises the following components by mass percentage: 30-40% of linear alkylbenzene sulfonate, 10-15% of fatty alcohol polyoxyethylene ether carboxylate, 8-12% of fatty acid methyl ester ethoxylate sulfonate, 2-5% of silicone polyether defoamer, 5-8% of chelating agent, 3-6% of cosolvent, pH regulator for adjusting the pH of the system to 7-8.5 and the balance of deionized water.

2. A hard water resistant low foaming LAS surfactant according to claim 1, characterized in that: The invention comprises the following components by mass percentage: 35% linear alkylbenzene sulfonate, 12% fatty alcohol polyoxyethylene ether carboxylate, 10% fatty acid methyl ester ethoxylate sulfonate, 3% silicone polyether defoamer, 6% chelating agent, 4% cosolvent, pH regulator for adjusting the system pH to 8 and the balance deionized water.

3. A hard water resistant low foaming LAS surfactant according to claim 1, characterized in that: The invention comprises the following components by mass percentage: 32% of linear alkylbenzene sulfonate, 10% of fatty alcohol polyoxyethylene ether carboxylate, 8% of fatty acid methyl ester ethoxylate sulfonate, 2% of silicone polyether defoamer, 5% of chelating agent, 3% of cosolvent, pH regulator for adjusting the pH of the system to 8 and the balance of deionized water.

4. A hard water resistant low foaming LAS surfactant according to any one of claims 1 to 3, characterized in that: The alkyl chain length of the linear alkylbenzene sulfonate is C10-C14, the carbon chain length of the fatty alcohol in the fatty alcohol polyoxyethylene ether carboxylate is C12-C14, and the degree of polymerization of the ethylene oxide is 3-5; the carbon chain length of the fatty acid methyl ester in the fatty acid methyl ester ethoxylate sulfonate is C16-C18, and the degree of ethoxylation is 5-7; the silicone polyether defoamer is formed by copolymerizing polydimethylsiloxane and polyether blocks, and the chain segment ratio of the two is 2:1-3:

1.

5. A hard water resistant low foaming LAS surfactant according to any one of claims 1 to 3, characterized in that: The chelating agent comprises 40-50% of ethylenediaminetetraacetic acid and its salts, 30-40% of diethylenetriaminepentaacetic acid and its salts, and 20-30% of aminotrimethylenephosphonic acid; and the cosolvent is a mixture of propylene glycol and ethylene glycol, with a mass ratio of 1:1-2:

1.

6. A hard water resistant low foaming LAS surfactant according to any one of claims 1 to 5, characterized in that: The polydimethylsiloxane chain segment of the silicone polyether defoamer has a molecular weight of 1000-3000 Da, and the polyether chain segment has an EO / PO block structure; the ethylenediaminetetraacetate in the chelating agent is a sodium salt or potassium salt, and the diethylenetriaminepentaacetate is a calcium sodium salt or magnesium salt; the fatty acid methyl ester ethoxylate sulfonate has a sulfonation degree of 70-90% and has a disulfonate structure.

7. A process for preparing a hard water resistant low foaming LAS surfactant according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Premixing: Add the calculated amount of deionized water to the reactor and start stirring at a speed of 200-300 r / min; add linear alkylbenzene sulfonate, fatty alcohol polyoxyethylene ether carboxylate, and fatty acid methyl ester ethoxylate sulfonate in sequence and stir for 15-20 minutes to preliminarily mix the components; Step 2: Adding additives: Add silicone polyether defoamer, chelating agent, and cosolvent to the above mixed system and continue stirring for 20-30 minutes to ensure that the additives are fully dispersed in the system; During this process, the temperature in the reactor is controlled at 30-40°C to prevent the silicone polyether defoamer from becoming ineffective due to excessive temperature. Step 3, pH adjustment: Use pH adjuster, pH adjuster is sodium hydroxide and citric acid, adjust the pH value of the system to 7-8.5, add while stirring, adjust the stirring speed to 150-200r / min, stirring time is 10-15min; Step 4: Homogenization: Transfer the mixed solution to a homogenizer and homogenize it under a pressure of 10-20 MPa for 10-15 minutes. Step 5: Filtration and packaging: The homogenized surfactant solution is filtered through a filter with a pore size of 0.2-0.5 μm to remove existing impurities and undissolved particles, and then packaged to obtain a finished hard water resistant low foaming LAS surfactant.

8. The process for preparing a hard water resistant low foaming LAS surfactant according to claim 7, wherein: In the step 1, the dissolution temperature of the linear alkylbenzene sulfonate is controlled at 40-50° C.; in the step 4, the homogenization treatment adopts a three-stage homogenization process, and the pressure gradient of each stage is 5-10 MPa; and in the step 5, after the filtration step, the content of particles with a particle size greater than 1 μm in the product is less than 0.1%.

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