A low pour point nonionic surfactant and a method for preparing the same

Abstract

The application provides a low pour point nonionic surfactant and a preparation method thereof, which is composed of the following raw materials in parts by weight: C13 isomeric fatty alcohol polyoxyethylene ether 18-30 parts, reverse EO / PO block copolymer 10-20 parts, sodium diisooctyl sulfosuccinate 1-7 parts, sodium dodecyl sulfonate 1-5 parts, glyceryl laurate 1-5 parts, isopropyl alcohol 5-10 parts, and propylene glycol 1-5 parts; the formula is constructed based on a nonionic surfactant as a main body, ion surfactants and additives are introduced, and the system is optimized, so that a low pour point nonionic surfactant with excellent adsorption capacity and decontamination capacity is obtained.

Description

Technical Field

[0001] This invention relates to the field of surfactant preparation, and in particular to a low pour point nonionic surfactant and its preparation method. Background Technology

[0002] Nonionic surfactants are surfactants that do not dissociate into ionic states in aqueous solutions. They can exist in water as neutral molecules or micelles, which is the core characteristic that distinguishes them from anionic, cationic, and amphoteric surfactants. Nonionic surfactants have high surface activity, good detergency, solubilization, emulsification, antistatic properties, calcium soap dispersion, low irritation, and excellent wetting properties. However, at lower temperatures, concentrated nonionic surfactant solutions tend to solidify and become non-flowable, making it difficult to guarantee their usability at low temperatures.

[0003] Nonionic surfactants can reduce the surface tension between water and oil, allowing oil stains to form emulsions in water, thus facilitating washing. They can also increase the solubility of other substances, which is crucial for cleaning and processing. Nonionic surfactants enable solutions to quickly penetrate solid surfaces, thereby improving washing efficiency. However, current nonionic surfactants suffer from a narrow application range. High-foaming surfactants tend to form stable foam layers, hindering wetting, while conventional low-foaming surfactants, although inhibiting foam formation, have a slow decrease in dynamic surface tension, making them unsuitable for rapid cleaning. Therefore, there is a need to research a low-pour-point nonionic surfactant. Summary of the Invention

[0004] One objective of this invention is to address the challenges of efficient, low-foaming, and stable cleaning of stubborn oil stains and difficult-to-wet substrates. A nonionic surfactant is prepared by using C13 isomeric fatty alcohol polyoxyethylene ether as the main component, synergistically compounded with inverse EO / PO block copolymers, and further enhanced with sodium diisooctyl succinate sulfonate, sodium dodecyl sulfonate, and glyceryl laurate as emulsifiers, with ethylene glycol and propylene glycol as solvents.

[0005] Another objective of this invention is to solve the problem of foam runaway in complex flow fields. Anionic additives sodium diisooctyl succinate sulfonate and sodium dodecyl sulfonate are added to a nonionic surfactant mainly composed of polyoxyethylene ether in C13 isomeric fatty alcohols to obtain a nonionic surfactant.

[0006] Another objective of this invention is to enhance the strong interfacial expansion ability of nonionic surfactants by using C13 isomeric fatty alcohol polyoxyethylene ether as the main component, which greatly improves the interfacial adsorption capacity.

[0007] Another objective of this invention is to provide a method for preparing a low-pour-point nonionic surfactant, which can simply and efficiently prepare a low-pour-point nonionic surfactant.

[0008] To achieve the above objectives, this invention discloses a low pour point nonionic surfactant, comprising, by weight, the following raw materials: 18-30 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 10-20 parts of reverse EO / PO block copolymer, 1-7 parts of sodium diisooctyl succinate sulfonate, 1-5 parts of sodium dodecyl sulfonate, 1-5 parts of glyceryl laurate, 5-10 parts of isopropanol, and 1-5 parts of propylene glycol. This formulation is based on a nonionic surfactant, with the introduction of ionic surfactants and auxiliaries to optimize the system. The C13 isomeric fatty alcohol polyoxyethylene ether forms micelles in aqueous solution, providing hydrophobic microdomains to accommodate oil contaminants. The hydrophobic alkyl chains of sodium dodecyl sulfonate and sodium diisooctyl succinate sulfonate insert into the hydrophobic core of the nonionic micelles through hydrophobic interactions, forming mixed micelles, which greatly improves the amount of oil contaminants that can be carried per unit volume of micelle. The C13 isomeric fatty alcohol polyoxyethylene ether, through van der Waals forces and... Anionic surfactants form a mixed adsorption layer. Due to its strong lipophilicity, glyceryl laurate tends to insert into the inner part of the adsorption layer near the oil phase, increasing the compressive modulus of the adsorption layer and preventing it from being easily destroyed by mechanical disturbances. C13 isomeric fatty alcohol polyoxyethylene ether and reverse EO / PO block copolymer form a composite interfacial film. C13 isomeric fatty alcohol polyoxyethylene ether provides the basic strength of the film, while the reverse EO / PO block copolymer provides steric hindrance and flexibility, maintaining interfacial stability during dynamic processes. The hydrogen bonds between C13 isomeric fatty alcohol polyoxyethylene ether and water molecules break with increasing temperature, resulting in a cloud point. The hydroxyl groups in isopropanol and propylene glycol form hydrogen bonds with water, while their alkyl groups can weakly interact with the hydrophobic chains of the surfactant. They insert into the hydration layer of the surfactant molecules, widening the temperature range for maintaining homogeneity and ensuring that phase separation does not easily occur at high temperatures and solidification does not easily occur at low temperatures. This multi-stage interconnected formulation yields a low-pour-point nonionic surfactant with comprehensive properties including high compatibilization capacity, fast dynamic wetting, controllable foaming, and wide temperature stability.

[0009] As a preferred embodiment, the product comprises, by weight, the following raw materials: 20-25 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 12-18 parts of reverse EO / PO block copolymer, 1-5 parts of sodium diisooctyl succinate sulfonate, 1-5 parts of sodium dodecyl sulfonate, 1-5 parts of glyceryl laurate, 5-10 parts of isopropanol, and 1-5 parts of propylene glycol.

[0010] Preferably, the C13 isomeric fatty alcohol polyoxyethylene ether has an EO value of 6-8, is synthesized by O-alkylation using a supported silica-alumina catalyst, and has an HLB value of 11.5-13.0; the reverse EO / PO block copolymer has an EO content of 30-50%; when the ethylene oxide addition number (EO value) of the C13 isomeric fatty alcohol polyoxyethylene ether is 6-8 and the hydrophilic-lipophilic balance value (HLB value) is in the range of 11.5-13.0, the C13 isomeric fatty alcohol polyoxyethylene ether under these conditions balances dynamic adsorption, decontamination, and stability, maximizing the satisfaction of low pour point dynamic adsorption and synergistic control. It exhibits excellent foaming and salt-resistant cloud point stability. The inverse EO / PO block copolymer with 30-50% EO content shows optimal compatibility with C13 isomeric fatty alcohol polyoxyethylene ether, achieving moderate foam control while retaining its indicative properties. It possesses strong cloud point buffering capacity, broadening the operating temperature window. During heating, this inverse block copolymer undergoes a globular-to-rod-like micelle transition before the C13 isomeric fatty alcohol polyoxyethylene ether, delaying the drastic separation of the main surfactant through steric hindrance. The hydrophobic interaction between the PO segments and the hydrophobic chains of the C13 alcohol ether forms a composite micelle structure at high temperatures, maintaining homogeneous stability over a wide temperature range. This effectively suppresses excessive foaming from anionic sodium dodecyl sulfonate while retaining a certain amount of foam for indication.

[0011] Preferably, the sodium diisooctyl succinate has an HLB value of 10-12; the sodium dodecyl sulfonate has an active ingredient content of 90-95% and an HLB value of 12-14. Sodium diisooctyl succinate with these values ​​has a bi-branched hydrophobic group and an ionic head group, which can rapidly reduce dynamic surface tension and simultaneously form a good mixed adsorption layer with two nonionic groups at the interface. This avoids repulsion due to excessive differences in hydrophilicity, and also prevents excessive insertion into the micelle core due to excessive oleophilicity, thus affecting the penetration rate. In this formulation, sodium dodecyl sulfonate of this specification primarily provides dispersion of particulate dirt and basic foaming properties. Its sufficient hydrophilicity allows for stable dispersion in the aqueous phase, and it adsorbs onto the particle surface to provide repulsion. Furthermore, it avoids completely detaching from the hydrophobic interface and losing its auxiliary effect on oil stains.

[0012] Preferably, the glyceryl laurate has an HLB value of 4-5 and an active ingredient content of 40-60%. This specification of glyceryl laurate is based on its structural complementarity in the composite micelles and interfacial film. Due to its strong lipophilicity, glyceryl laurate tends to deeply insert into the hydrophobic side of the adsorption layer, filling the gaps between the hydrophobic chains of the C13 isomeric fatty alcohol polyoxyethylene ether main surfactant, thus increasing the density of the interfacial film. In the bulk phase, its insertion into the micelle fence layer increases the inter-chain spacing of the C13 isomeric fatty alcohol polyoxyethylene ether, forming swollen micelles. Although the apparent aggregation number of micelles decreases, the volume of the hydrophobic core expands significantly due to the incorporation of glyceryl laurate. This enhances solubility through solubilization space expansion rather than micelle contraction, while also creating a loose... The barrier layer lowers the energy barrier for surfactant molecules to migrate to the interface, improving the dynamic wetting rate. Its glycerol head group interacts with the EO chain or water molecules of adjacent surfactants through hydrogen bonds, enhancing the cohesive energy and mechanical strength of the interfacial film and significantly improving the stability of the emulsion. Glyceryl laurate can also increase the effective volume of micelles and improve solubility. In addition, glyceryl laurate can first anchor on the hydrophobic substrate, assisting the subsequent adsorption of the main surfactant, enhancing the adhesion of the entire formulation to the difficult-to-wet substrate, and reducing the solid / liquid interfacial tension. At the same time, glyceryl laurate can be inserted into the adsorption layer formed by anions such as sodium dodecyl sulfonate, which can play a buffering role. It can also synergistically work with propylene glycol in the formulation to maintain the water activity and viscosity stability of the system.

[0013] Preferably, the purity of the isopropanol is 99.5-99.9%; the purity of the propylene glycol is 99.5-99.8%; the isopropanol and propylene glycol constitute the solvent of the formulation, which can regulate micelle behavior, reduce interfacial energy, optimize rheological properties, and broaden environmental adaptability; the isopropanol significantly reduces the interfacial energy of the system, ensuring the coexistence of C13 isomeric fatty alcohol polyoxyethylene ether and reverse EO / PO block copolymer in the aqueous phase; and works synergistically with sodium diisooctyl succinate sulfonate to enhance the low pour point characteristics.

[0014] This invention also provides a method for preparing a low-pour-point nonionic surfactant, comprising the following steps: S1. Add C13 isomeric fatty alcohol polyoxyethylene ether, reverse EO / PO block copolymer, glyceryl laurate, isopropanol, and propylene glycol to the reactor and stir to mix; then add sodium dodecyl sulfonate powder to the mixture. S2. Slowly add the sodium diisooctyl succinate sulfonate solution into the reactor and stir. S3. Reduced pressure distillation: Increase the temperature in the reactor, turn on the stirrer, and reduce the pressure in the reactor to obtain the crude product, nonionic surfactant. S4. Turn off the vacuum pump, slowly introduce dry nitrogen gas, cool the material with stirring, adjust the pH, filter, and obtain a nonionic surfactant.

[0015] Preferably, the stirring temperature of S1 is 45-55℃, the stirring speed is 60-120rpm, and the stirring time is 1-2h; the sodium dodecyl sulfonate powder is added while stirring, with a stirring temperature of 50-60℃, a stirring speed of 80-100rpm, and a stirring time of 30-40min.

[0016] Preferably, the stirring speed of S2 is 100-150 rpm, the stirring temperature is 45-55℃, and the stirring time is 30-45 min; the stirring temperature of S3 is 60-70℃, the stirring speed is 30-50 rpm, and the reactor pressure is reduced to -0.08MPa~-0.095MPa.

[0017] Preferably, the S4 is cooled to 20-25°C, the pH is adjusted to 6.0-7.0 using citric acid, and the filter screen used for filtration is 200 mesh.

[0018] The beneficial effects of this invention are: 1. Excellent interface performance, enabling extremely rapid dynamic wetting; the low pour point nonionic surfactant of this invention can quickly bring the surface tension to the equilibrium value during dynamic processes such as high-pressure spraying, high-speed spraying, and rapid impregnation, solving the problem of poor wetting caused by conventional surfactants not being able to adsorb in time under high-speed conditions, ensuring instant spread during operation, without pinholes or blind spots; it can penetrate into tiny gaps, the interior of fibers, and the bottom of dense oil stains to achieve thorough purification.

[0019] 2. Improved cleaning efficiency: The nonionic surfactant of this invention has a significantly increased solubilizing capacity, a loose mixed micelle structure, and an increased core volume, which enhances its capacity to accommodate mineral oil, animal and vegetable oils, and complex dirt; the surface is highly smooth after cleaning and there is no ash residue.

[0020] 3. Wide adaptability, which can meet a variety of cleaning conditions; the nonionic surfactant of this invention has a wide operating temperature range, ensuring that it can be used in the range of 0-60℃, and it remains clear and transparent in hard water without reducing its detergency.

[0021] 4. Fast action time: The nonionic surfactant of this invention has a rapid desorption capability, and the surfactant quickly leaves the interface and is washed away with water during rinsing; it can also reduce water residue; after cleaning, the surface is free of white spots and slippery feeling, which can meet the high cleanliness requirements of the electronics, optics, food and other industries.

[0022] 5. The nonionic surfactant of the present invention has a low pour point and will not solidify at low temperatures, thus exhibiting good low-temperature fluidity. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments.

[0024] General Implementation Examples: 18-30 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 10-20 parts of reverse EO / PO block copolymer, 1-7 parts of sodium diisooctyl succinate sulfonate, 1-5 parts of sodium dodecyl sulfonate, 1-5 parts of glyceryl laurate, 5-10 parts of isopropanol, and 1-5 parts of propylene glycol.

[0025] Preparation method: S1. C13 isomeric fatty alcohol polyoxyethylene ether, reverse EO / PO block copolymer, glyceryl laurate, isopropanol, and propylene glycol are added to a reactor and stirred for 1-2 hours at a temperature of 45-55℃ and a stirring speed of 60-120 rpm. After stirring is completed and the mixed liquid in the reactor is stable, sodium dodecyl sulfonate powder (200-220 mesh) is added while stirring at a stirring temperature of 50-60℃, a stirring speed of 80-100 rpm, and a stirring time of 30-40 minutes. S2. Slowly add the sodium dioctyl succinate sulfonate solution (70%-80% sodium dioctyl succinate sulfonate) into the reactor, stirring at 100-150 rpm, at 45-55°C, for 30-45 minutes. S3. Introduce the liquid in the reactor into the distillation tower, slowly heat it to 60-70℃ under normal pressure, stir at 30-50 rpm, gradually evacuate the vacuum, reduce the pressure to -0.08MPa~-0.095MPa, and maintain the temperature at 60-70℃. S4. Slowly introduce dry nitrogen gas and cool the material to 20-25℃ with stirring. Adjust the pH to 6.0-7.0 with citric acid, and then filter it with a 200-mesh filter to obtain the final product. Example 1:

[0026] 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0027] Preparation method: S1. C13 isomeric fatty alcohol polyoxyethylene ether, reverse EO / PO block copolymer, glyceryl laurate, isopropanol, and propylene glycol are added to the reactor and stirred for 1.5 hours at 50°C and 90 rpm. After stirring is complete and the mixture in the reactor is stable, sodium dodecyl sulfonate powder (200 mesh) is added while stirring at 55°C, 90 rpm, and 35 minutes. S2. Slowly add the sodium dioctyl succinate sulfonate solution (75% sodium dioctyl succinate sulfonate) into the reactor, stirring at 120 rpm and 50°C for 30 min. S3. Introduce the liquid in the reactor into the distillation tower, slowly heat it to 65°C under normal pressure, stir at 40 rpm, gradually evacuate the vacuum, reduce the pressure to -0.08MPa~-0.095MPa, and maintain the temperature at 65°C. S4. Slowly introduce dry nitrogen gas, cool the material to 25°C with stirring, adjust the pH to 7.0 with citric acid, and then filter it through a 200-mesh filter to obtain the final product. Example 2:

[0028] Raw materials: 18 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0029] The preparation method is the same as in Example 1. Example 3:

[0030] Raw materials: 20 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0031] The preparation method is the same as in Example 1. Example 4:

[0032] Raw materials: 28 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0033] The preparation method is the same as in Example 1. Example 5:

[0034] Raw materials: 30 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0035] The preparation method is the same as in Example 1. Example 6:

[0036] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 10 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0037] The preparation method is the same as in Example 1. Example 7:

[0038] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 12 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0039] The preparation method is the same as in Example 1. Example 8:

[0040] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 18 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0041] The preparation method is the same as in Example 1. Example 9:

[0042] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 20 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0043] The preparation method is the same as in Example 1. Example 10:

[0044] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 1 part of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0045] The preparation method is the same as in Example 1. Example 11:

[0046] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 5 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0047] The preparation method is the same as in Example 1. Example 12:

[0048] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 7 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0049] The preparation method is the same as in Example 1. Example 13:

[0050] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 1 part of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0051] The preparation method is the same as in Example 1. Example 14:

[0052] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 5 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0053] The preparation method is the same as in Example 1. Example 15:

[0054] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 1 part of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0055] The preparation method is the same as in Example 1. Example 16:

[0056] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 5 parts of glyceryl laurate, 7 parts of isopropanol, and 3 parts of propylene glycol.

[0057] The preparation method is the same as in Example 1. Example 17:

[0058] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 5 parts of isopropanol, and 3 parts of propylene glycol.

[0059] The preparation method is the same as in Example 1. Example 18:

[0060] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 10 parts of isopropanol, and 3 parts of propylene glycol.

[0061] The preparation method is the same as in Example 1. Example 19:

[0062] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 1 part of propylene glycol.

[0063] The preparation method is the same as in Example 1. Example 20:

[0064] Raw materials: 24 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts of reverse EO / PO block copolymer, 4 parts of sodium diisooctyl succinate sulfonate, 3 parts of sodium dodecyl sulfonate, 3 parts of glyceryl laurate, 7 parts of isopropanol, and 5 parts of propylene glycol.

[0065] The preparation method is the same as in Example 1. Comparative Example 1:

[0066] Raw materials: 24 parts C13 isomeric fatty alcohol polyoxyethylene ether, 4 parts sodium diisooctyl succinate sulfonate, 3 parts sodium dodecyl sulfonate, 3 parts glyceryl laurate, 7 parts isopropanol, and 3 parts propylene glycol. This comparative example lacks an inverse EO / PO block copolymer.

[0067] Preparation method: No reverse EO / PO block copolymer was added during mixing in S1, and all other steps were the same as in Example 1. Comparative Example 2:

[0068] Raw materials: 24 parts C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts reverse EO / PO block copolymer, 3 parts sodium dodecyl sulfonate, 3 parts glyceryl laurate, 7 parts isopropanol, and 3 parts propylene glycol. This comparative example omits sodium diisooctyl succinate sulfonate.

[0069] Preparation method: Step S2 is removed, and the remaining steps are the same as in Example 1. Comparative Example 3:

[0070] Raw materials: 24 parts C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts reverse EO / PO block copolymer, 4 parts sodium diisooctyl succinate sulfonate, 3 parts glyceryl laurate, 7 parts isopropanol, and 3 parts propylene glycol. Sodium dodecyl sulfonate is missing from this comparative example.

[0071] Preparation method: S1, C13 isomeric fatty alcohol polyoxyethylene ether, reverse EO / PO block copolymer, glyceryl laurate, isopropanol, and propylene glycol are added to a reactor and stirred for 1-2 hours at a temperature of 45-55℃ and a stirring speed of 60-120 rpm. After stirring is complete and the mixture in the reactor stabilizes, the stirring temperature is maintained at 50-60℃, the stirring speed at 80-100 rpm, and the stirring time at 30-40 minutes. The remaining steps are the same as in Example 1. Comparative Example 4:

[0072] Raw materials: 24 parts C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts reverse EO / PO block copolymer, 4 parts sodium diisooctyl succinate sulfonate, 3 parts sodium dodecyl sulfonate, 7 parts isopropanol, and 3 parts propylene glycol. This comparative example omits glyceryl laurate.

[0073] Preparation method: No glyceryl laurate was added during mixing in S1, and the other steps were the same as in Example 1. Comparative Example 5:

[0074] Raw materials: 24 parts C13 isomeric fatty alcohol polyoxyethylene ether, 15 parts reverse EO / PO block copolymer, 4 parts sodium diisooctyl succinate sulfonate, 3 parts sodium dodecyl sulfonate, and 3 parts glyceryl laurate. Isopropanol and propylene glycol are omitted in this comparative example.

[0075] Preparation method: Isopropanol and propylene glycol were not added during mixing in S1, and the other steps were the same as in Example 3.

[0076] The performance of the nonionic surfactants prepared in Examples 1-20 and Comparative Examples 1-5 was tested. A 1% surfactant solution was prepared to test the cloud point. Then, a 0.5% surfactant solution was prepared by diluting it with warm water at 40°C and the surface tension was tested. For cleaning industrial components, a 14% solution was prepared to test the detergency (cleaning rate %) and degreasing time s. The cleaning rate was (weight of the sample before cleaning - weight of the sample after cleaning) / weight of dirt × 100%.

[0077] Table 1 Performance tests of Examples 1-20

[0078]

[0079] The above results show that the nonionic surfactant of this invention has excellent performance, a suitable cloud point for use in medium and high temperature environments, strong detergency, fast wetting rate, good cleaning effect, and a low pour point, allowing it to remain unsolidified at lower temperatures and exhibiting good low-temperature fluidity. Examples 1-5 describe the effect of varying the amount of C13 isomeric fatty alcohol polyoxyethylene ether added on the nonionic surfactant. As the amount increases, the cloud point gradually decreases because C13 isomeric fatty alcohol polyoxyethylene ether is sensitive to heating. Furthermore, as the main component of the nonionic surfactant, different amounts of C13 isomeric fatty alcohol polyoxyethylene ether can be added within the scope of this invention to change the cloud point according to different environmental requirements. As the amount increases, the surface tension decreases significantly, then decreases slowly. Highly branched C13 isomeric fatty alcohol polyoxyethylene ether has a lower density than branched carbon chain structures, effectively covering the interface. The ethylene oxide head group provides hydrophilicity, enabling rapid adsorption at extremely low concentrations. As the amount increases, the washing efficiency improves and the degreasing time decreases. C13 isomeric fatty alcohol polyoxyethylene ether has excellent penetrating and emulsifying power. Polyoxyethylene ether can encapsulate stains to form an emulsion, which has the greatest impact on the cleaning rate.

[0080] Examples 1 and 6-9 illustrate the effect of the amount of inverse EO / PO block copolymer added on the nonionic surfactant. As its content increases, the surfactant content initially increases and then slowly decreases, surface tension decreases, cleaning efficiency increases, and degreasing time remains relatively unchanged. When treating stains, the inverse EO / PO block copolymer can synergistically adsorb stain particles with C13 isomeric fatty alcohol polyoxyethylene ether, forming a thick hydration layer on the surface to prevent oil droplets or stains from coalescing and depositing, greatly improving the cleaning efficiency. Furthermore, the EO / PO block copolymer is unaffected by water hardness. In addition, the inverse EO / PO block copolymer has antifoaming properties, which can counteract the foaming tendency of sodium diisooctyl succinate sulfonate and sodium dodecyl sulfonate, indirectly improving the efficiency of mechanical cleaning.

[0081] Examples 1 and 10-12 illustrate the effect of the amount of sodium diisooctyl succinate added on nonionic surfactants. In this study, with the addition of two ionic additives, the increased amount of sodium diisooctyl succinate significantly increased the cloud point. Its molecule possesses a bibranched hydrophobic structure and a sulfonic acid head group, which can weaken micelle aggregation during heating, thus greatly increasing the cloud point. It can also reduce surface tension; sodium diisooctyl succinate has high surface activity, significantly reducing surface tension. Furthermore, the structure of sodium diisooctyl succinate allows for extremely fast penetration, enabling the surfactant to quickly penetrate dense oil films or dirt layers, rapidly contacting the substrate, thereby accelerating the detergency process and improving cleaning efficiency.

[0082] Examples 1 and 13-14 illustrate the effect of sodium dodecyl sulfonate addition on nonionic surfactants. As the amount of sodium dodecyl sulfonate used increases, the cloud point increases, the surface tension decreases, the cleaning rate increases, and the degreasing time decreases. The effect of sodium dodecyl sulfonate alone is weaker than that of sodium diisooctyl succinate, but the two can have a synergistic effect. The effects of the two are superimposed, which weakens the aggregation of micelles during heating. The same applies to other effects.

[0083] Examples 1 and 15-16 illustrate the effect of the amount of glyceryl laurate added on nonionic surfactants. Increasing the amount of glyceryl laurate has little effect on the cloud point, reduces surface tension, improves cleaning efficiency, and prolongs degreasing time. At the oil-water interface, glyceryl laurate is embedded between emulsifiers, which can fill the gaps in the interfacial film and improve the stability of the emulsion. The strong lipophilicity of glyceryl laurate causes the surfactant micelles to become loose, which helps the surfactant molecules to be transported to the interface more quickly, improving the cleaning efficiency, but it will delay the degreasing time.

[0084] Examples 1 and 17-20 illustrate the effect of the amount of isopropanol and propylene glycol added on nonionic surfactants. The solubilizer has a relatively small effect on the nonionic surfactant because the nonionic surfactant prepared in this invention is a concentrated form. Isopropanol can reduce the viscosity of the concentrate, making it uniform, clear, and fluid; propylene glycol can prevent the surfactant from precipitating out of the concentrate.

[0085] Example 1, test results of Comparative Examples 1-5.

[0086]

[0087] As can be seen from Example 1 and Comparative Examples 1-5, the components of the present invention work synergistically. The absence of any one component will reduce the properties of the nonionic surfactant of the present invention. Comparative Example 1 lacks the reverse EO / PO block copolymer, resulting in a severe decrease in detergency. Comparative Example 2 lacks sodium diisooctyl succinate, resulting in a significant decrease in cloud point and detergency. Comparative Example 3 lacks sodium dodecyl sulfonate, resulting in a decrease in cleaning power for solid dirt, a decrease in detergency, and a decrease in cloud point. Comparative Example 4 lacks glyceryl laurate, resulting in poor stability, a decrease in cloud point, and a reduction in detergency. Comparative Example 5 lacks a solvent, resulting in a decrease in various properties. In addition, Comparative Examples 1-5 all have defects. Comparative Example 1 lacks the inverse EO / PO block copolymer, resulting in a significant increase in the number of foam layers. The lack of the inverse EO / PO block copolymer leads to increased surface tension, reduced spreading line, and inability to break the liquid film. Block copolymer molecules can insert into the bubble liquid film, but due to the hydrophobicity and coiled structure of its PO segments, they cannot form a tight arrangement, making the foam difficult to maintain. After its loss, the foam becomes very stable and not easy to break. Comparative Example 2 lacked sodium diisooctyl succinate sulfonate, resulting in increased surface tension but decreased foam stability, thus the change in foam suppression performance was minimal. Comparative Example 3 lacked sodium dodecyl sulfonate, also resulting in increased surface tension and decreased foam stability. The two ionic surfactants can improve the rapid penetration ability of the product and also increase the strength of the liquid film. Comparative Example 4 lacked glyceryl laurate, which slightly decreased the foam suppression ability of the formulation and increased surface tension. Glyceryl laurate is a highly lipophilic surfactant with foam suppression ability, which can effectively interfere with the stability of the bubble liquid film. Comparative Example 5 lacked isopropanol and propylene glycol. The presence of isopropanol and propylene glycol as additives led to decreased stability and a decline in various properties, especially affecting the low pour point.

[0088] In addition, a comparison between Example 1 and Comparative Example 1 revealed that when the temperature was raised above the cloud point by 5°C, Example 1 formed an emulsion, while Comparative Example 1 formed a stratified precipitate. Upon cooling below the cloud point, Example 1 returned to its clear and transparent state, while Comparative Example 1 still exhibited precipitate. When Comparative Example 5 and Example 1 were used in winter (-5 to -10°C), Comparative Example 1 showed significant solidification, while Example 1 remained usable.

[0089] Based on the above results, it can be seen that the nonionic surfactant of the present invention has the characteristics of low pour point, and has the advantages of superior cloud point, low pour point, low foaming and fast wetting speed.

[0090] It should be noted that the above embodiments and comparative examples are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the present invention.

Claims

1. A low pour point nonionic surfactant, characterized in that, By weight, C13 isomeric fatty alcohol polyoxyethylene ether 18-30 parts, reverse EO / PO block copolymer 10-20 parts, sodium diisooctyl succinate sulfonate 1-7 parts, sodium dodecyl sulfonate 1-5 parts, glyceryl laurate 1-5 parts, isopropanol 5-10 parts, and propylene glycol 1-5 parts.

2. The low pour point nonionic surfactant according to claim 1, characterized in that, By weight, 20-25 parts of C13 isomeric fatty alcohol polyoxyethylene ether, 12-18 parts of reverse EO / PO block copolymer, 1-5 parts of sodium diisooctyl succinate sulfonate, 1-5 parts of sodium dodecyl sulfonate, 1-5 parts of glyceryl laurate, 5-10 parts of isopropanol, and 1-5 parts of propylene glycol.

3. A low pour point nonionic surfactant according to claim 1 or 2, characterized in that, The C13 isomeric fatty alcohol polyoxyethylene ether has an EO value of 6-8, is synthesized by O-alkylation using a supported silica-alumina catalyst, and has an HLB value of 11.5-13.0; the reverse EO / PO block copolymer has an EO content of 30-50%.

4. A low pour point nonionic surfactant according to claim 1 or 2, characterized in that, The sodium diisooctyl succinate sulfonate has an HLB value of 10-12; the sodium dodecyl sulfonate has an active ingredient content of 90-95% and an HLB value of 12-14.

5. A low pour point nonionic surfactant according to claim 1 or 2, characterized in that, The glyceryl lauryl ester has an HLB content of 4-5 and an active ingredient content of 40-60%.

6. A low pour point nonionic surfactant according to claim 1 or 2, characterized in that, The purity of the isopropanol is 99.5-99.9%; the purity of the propylene glycol is 99.5-99.8%.

7. A method for preparing a low pour point nonionic surfactant, characterized in that, The preparation of a low pour point nonionic surfactant according to claims 1-6 comprises the following steps: S1. Add C13 isomeric fatty alcohol polyoxyethylene ether, reverse EO / PO block copolymer, glyceryl laurate, isopropanol, and propylene glycol to the reactor and stir to mix; then add sodium dodecyl sulfonate powder to the mixture. S2. Slowly add the sodium diisooctyl succinate sulfonate solution into the reactor and stir. S3. The liquid from the reactor is introduced into a distillation column, and vacuum distillation is performed to increase the temperature in the column. Stirring is then turned on to reduce the pressure in the column, and crude nonionic surfactant is obtained. S4. Slowly introduce dry nitrogen gas, cool the material with stirring, adjust the pH, filter, and obtain a nonionic surfactant.

8. A low pour point nonionic surfactant according to claim 7, characterized in that, The stirring temperature of S1 is 45-55℃, the stirring speed is 60-120rpm, and the stirring time is 1-2h; the sodium dodecyl sulfonate powder is added while stirring, the stirring temperature is 50-60℃, the stirring speed is 80-100rpm, and the stirring time is 30-40min.

9. A low pour point nonionic surfactant according to claim 7, characterized in that, The stirring speed of S2 is 100-150 rpm, the stirring temperature is 45-55℃, and the stirring time is 30-45 min; the stirring temperature of S3 is 60-70℃, the stirring speed is 30-50 rpm, and the reactor pressure is reduced to -0.08MPa~-0.095MPa.

10. A low pour point nonionic surfactant according to claim 7, wherein S4 is cooled to 20-25°C, the pH is adjusted to 6.0-7.0 using citric acid, and the filter screen used for filtration is 200 mesh.

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