A low-foam machine washing composition based on modified nonionic surfactant and preparation method thereof

Abstract

The invention relates to the field of daily chemical industry, and in particular to a low-foam machine washing composition based on a modified non-ionic surfactant and a preparation method thereof. The low-foam machine washing composition comprises the following components by mass percentage: 1% to 20% of a non-ionic surfactant, 1% to 10% of a bacteriostatic agent, 0.1% to 15% of a chelating agent, 0.1% to 10% of a cosolvent, 0.1% to 10% of an auxiliary agent, and the remainder of water; the non-ionic surfactant is a fatty alcohol block polyether obtained by successively adding fatty alcohol to ethylene oxide and then reacting with ethyl chloride to introduce a branched chain structure; the polymer compound has extremely low foam, with a foaming force of less than 8mm, and can produce a synergistic effect after being compounded with a chelating agent, a bacteriostatic agent and other components, thereby helping to significantly reduce the foaming force of the cleaning composition, while further enhancing the stability and bacteriostatic performance of the product, and effectively improving the product performance.

Description

Technical Field

[0001] The invention relates to the field of daily chemical industry, in particular to a low-foam machine washing composition based on a modified nonionic surfactant and a preparation method thereof. Background Art

[0002] A floor scrubber is a cleaning machine that is suitable for cleaning hard floors and sucking out wastewater at the same time, and taking the wastewater away from the site. It has the advantages of environmental protection, energy saving, and high efficiency. It is widely used in various occasions such as shopping malls, hospitals, schools, stations, airports, homes, etc. It can clean various floors including concrete, marble, tiles, floors, etc. Using a floor scrubber can greatly improve cleaning efficiency, reduce the workload of cleaning staff, and achieve better cleaning results.

[0003] After the floor scrubber is started, the clean water and detergent will be mixed evenly in proportion, and the mixed cleaning liquid will automatically flow to the brush disc at the bottom of the floor scrubber. The friction of the disc brush and roller brush rotating on the ground and the detergent will remove the dirt on the ground and clean it. The power of the disc brush and roller brush of the floor scrubber comes from the motor, which cleans the ground through physical friction. For high-speed rotating equipment, using ordinary floor cleaners is prone to produce a lot of foam, which will affect the life of the fan and even cause a short circuit, making the equipment malfunction and unable to work. Therefore, the floor scrubber needs to be used with a special low-foam floor cleaner.

[0004] Chinese patent CN201810880577.4 discloses a floor cleaner and a preparation method thereof, comprising 0.1% to 0.2% carbomer, 0.2% to 0.3% sunscreen, 5% to 8% fatty alcohol polyoxyethylene ether, 0.35% to 0.5% triethanolamine, 2% to 3% isomeric tridecanol, 0.1% to 0.2% silver ions, 0.1% to 0.5% microcapsule flavors, 0.1% preservatives, 1.8% to 2.3% sodium citrate and the remainder deionized water. However, surfactants such as fatty alcohol polyethers in the cleaner reduce the coefficient of friction of the floor, making it easy for people to fall and get injured when walking; and the cleaner contains surfactant components with strong foaming properties, which will generate a large amount of foam when rinsing cleaning tools, and is not suitable for use with floor scrubbers. Therefore, it is necessary to develop a low-foaming machine-washable floor cleaning composition for use with floor scrubbers. Summary of the invention

[0005] The present invention aims at the deficiencies in the prior art and provides a low-foam machine-washing composition based on a modified nonionic surfactant and a preparation method thereof. The machine-washing floor cleaning composition comprises a nonionic surfactant, an antibacterial agent, a chelating agent, a cosolvent, an auxiliary agent and water, wherein the nonionic surfactant is an extremely low-foam fatty alcohol block polyether with a foaming power of less than 9 mm obtained by addition reaction of fatty alcohol with ethylene oxide and propylene oxide and then substitution reaction with ethyl chloride, thereby solving the problem that the current floor cleaning composition contains a surfactant component with strong foaming performance and generates a large amount of foam when used.

[0006] To achieve the above purpose, the specific technical solutions of the present invention are as follows: The invention provides a low-foam machine washing composition based on a modified nonionic surfactant, comprising the following components in mass fractions: 1% to 20% of a nonionic surfactant, 1% to 10% of an antibacterial agent, 0.1% to 15% of a chelating agent, 0.1% to 10% of a cosolvent, 0.1% to 10% of an auxiliary agent, and the balance being water.

[0007] Furthermore, the antibacterial agent is selected from one or more of benzalkonium chloride, didecyldimethylammonium chloride, polyhexamethylene biguanide hydrochloride, and silver ions.

[0008] Furthermore, the chelating agent is selected from one or more of methylglycine diacetate trisodium salt, aminocarboxylic acid compounds, organic aminophosphonic acid compounds, sodium citrate, ammonium citrate, and potassium sodium tartrate.

[0009] Furthermore, the cosolvent is selected from one or more of glycerol, propylene glycol, isohexylene glycol, diethylene glycol butyl ether, and sorbitol.

[0010] Furthermore, the auxiliary agent is selected from one or more of preservatives, flavors, and pigments.

[0011] Furthermore, the nonionic surfactant is a fatty alcohol block polyether, and the fatty alcohol block polyether is obtained by using a fatty alcohol as a starter and an acidic catalyst as an initiator, successively reacting with ethylene oxide and propylene oxide, and then reacting with ethyl chloride under the action of an alkaline catalyst to undergo a substitution reaction.

[0012] Furthermore, the fatty alcohol is one or more of C12-C18 isomeric fatty alcohols.

[0013] Further, the preparation method of fatty alcohol block polyether is as follows: (1) The initiator and the acid catalyst are placed in a reaction kettle, the atmosphere in the kettle is replaced with nitrogen three times, and then ethylene oxide is added to form an intermediate 1 by ring-opening addition reaction; (2) intermediate 1 is placed in a reaction kettle, and after dehydration for 1 to 2 hours at a vacuum degree of ≥0.095 MPa and 100 to 120°C, propylene oxide is added for ring-opening addition to form intermediate 2. After the reaction is completed, post-treatment is performed to remove the acidic catalyst; (3) The intermediate 2 is placed in a reaction kettle, mixed evenly with the alkaline catalyst under anaerobic conditions, and dehydrated for 1 to 2 hours at 100 to 120° C. and a stirring speed of 300 to 500 rpm; (4) The mixture is cooled to 90-100°C, and ethyl chloride is added to carry out ethylation reaction. After the reaction is completed, desalination treatment is carried out to obtain fatty alcohol block polyether.

[0014] Furthermore, in step (1), the acidic catalyst is one or more of aluminum perchlorate, magnesium perchlorate, and zinc perchlorate, and the amount of the acidic catalyst added is 0.1% to 0.5% of the amount of the initiator substance.

[0015] Furthermore, in the step (1), the molar ratio of ethylene oxide to the initiator is 2-3 mol:1 mol, and the intermediate 1 is fatty alcohol polyoxyethylene ether.

[0016] Furthermore, the reaction temperature of the ring-opening addition in step (1) is 100-120° C., and the reaction pressure is 0.1-0.3 MPa.

[0017] Furthermore, in the step (2), the molar ratio of propylene oxide to the initiator is 1-2 mol:1 mol, and the intermediate 2 is a fatty alcohol propylene oxide adduct.

[0018] Furthermore, the alkaline catalyst in step (3) is one or more of sodium hydroxide, potassium hydroxide, and sodium methoxide, and the alkaline catalyst is 0.1% to 0.5% of the mass of the intermediate 2.

[0019] Furthermore, in step (3) and step (4), the molar ratio of the intermediate 2, the alkaline catalyst and ethyl chloride is 1 mol: 5-6 mol: 5-6 mol.

[0020] The present invention uses fatty alcohol and ethylene oxide as main raw materials, and uses perchlorate as an acidic catalyst. The perchlorate is hydrolyzed or alcoholyzed to be acidic and can activate ethylene oxide to form a positive carbon ion. The positive carbon ion then reacts with alcohol to form a fatty alcohol polyoxyethylene ether oligomer with a certain molecular weight, and the obtained product has less by-products; then the fatty alcohol polyoxyethylene ether reacts with propylene oxide to obtain a propylene oxide adduct; the propylene oxide adduct is subjected to a dehydration pretreatment and then reacts with ethyl chloride under the action of an alkaline catalyst to obtain a fatty alcohol block polyether. The dehydration pretreatment in step (3) can effectively remove moisture, avoid side reactions caused by moisture, thereby improving the selectivity of the reaction and causing the reaction to proceed in the direction of generating a fatty alcohol block polyether; for alkaline catalysts, moisture will reduce their activity. Dehydration treatment can ensure that the alkaline catalyst maintains a high catalytic activity in subsequent reactions, thereby accelerating the reaction process and improving the reaction efficiency. Therefore, the pretreatment in step (3) is indispensable. Without this step, the subsequent substitution reaction cannot proceed.

[0021] The traditional method mainly prepares low-foam polyether surfactants by polycondensation with ethylene oxide and propylene oxide, and the defoaming and foam-suppressing effects of the obtained surfactants cannot meet the low-foam requirements of the cleaning composition used in the floor scrubber. However, the present invention successfully introduces a branched structure through a substitution reaction of halogenated hydrocarbons after addition, and the positions of the introduced ethyl groups are various. The formed fatty alcohol block polyether has a large number of isomeric molecular chain arrangements, resulting in countless arrangement modes, so the fatty alcohol block polyether is not easy to produce crystal orientation arrangement and has lower foam; and because the ethyl group introduced by the substitution reaction is an alkyl group, it has lipophilicity, hydrophobicity and permeability, and has a strong effect on reducing surface tension, further playing a role in defoaming and foam-suppressing, so the obtained fatty alcohol block polyether has extremely low foaming power, less than 9mm.

[0022] The present invention provides a low-foam machine-washable floor cleaning composition, and a specific preparation method comprises the following steps: S1: Add some water, nonionic surfactant and cosolvent into a stirring pot and stir evenly; S2: Add the remaining amount of water, antibacterial agent, and chelating agent, stir evenly, and adjust the pH to an appropriate range; S3: Finally, add the remaining auxiliary agents and stir evenly to obtain a low-foam machine-washable floor cleaning composition.

[0023] Furthermore, the suitable range of pH adjustment in step S2 is 6.5 to 7.0.

[0024] The fatty alcohol block polyether obtained in the present invention has an extremely low foam with a foaming power of less than 9 mm. Chelating agents such as trisodium methylglycine diacetate can combine with metal ions in water to effectively prevent the metal ions from interacting with surfactants to form stable foams. Through the chelation effect, the influence of metal ions on the foam stability is reduced. The polyether works together with non-ionic surfactants to synergistically reduce the foaming power of the cleaning composition, so that the cleaning composition meets the requirements of the floor scrubber for low-foam cleaning compositions.

[0025] The fatty alcohol block polyether successfully introduced a branched structure through a substitution reaction. The introduction of the branched structure destroyed the orderly arrangement of the molecules, increased the disorder of the molecules, and made the molecules more stable. At the same time, the branched structure produced a steric hindrance effect, which weakened the interaction between molecules and reduced the tendency of aggregation and precipitation between molecules. Due to the special molecular structure of the fatty alcohol block polyether, it can be more evenly dispersed in water in the cleaning composition system, and is not easy to agglomerate and precipitate, thereby maintaining the stability of the cleaning composition.

[0026] The chemical stability of the fatty alcohol block polyether makes it less susceptible to decomposition or deterioration due to external factors. After compounding with antibacterial agents and other ingredients, the fatty alcohol block polyether provides the basis for chemical stability, while the antibacterial agent further enhances the stability of the cleaning composition by inhibiting the action of microorganisms. The two work together to ensure that the cleaning composition maintains more stable performance during storage and use. The fatty alcohol block polyether will also affect the growth environment of microorganisms to a certain extent. By reducing the surface tension, the contact between the microorganisms and the cleaning composition is more complete, and the effect of the antibacterial agent on the microorganisms is increased. At the same time, the low foaming characteristics of the fatty alcohol block polyether can reduce the interference of the foam on the action of the antibacterial agent, so that the antibacterial agent can play a better role. The fatty alcohol block polyether is compounded with the antibacterial agent, the antibacterial agent is the main antibacterial component, and the fatty alcohol block polyether agent assists the antibacterial agent by improving the growth environment of microorganisms and reducing interference factors. The two work synergistically to significantly improve the antibacterial performance of the cleaning composition, providing better hygiene protection for floor cleaning.

[0027] The beneficial effects of the present invention are: The invention provides a low-foam machine washing composition based on a modified nonionic surfactant, wherein the composition contains a fatty alcohol block polyether nonionic surfactant, wherein the high molecular compound fatty alcohol block polyether is prepared by using a fatty alcohol as a starter and an acidic catalyst as an initiator, reacting with ethylene oxide to obtain a fatty alcohol polyoxyethylene ether, and then reacting with propylene oxide to obtain a propylene oxide adduct, and the propylene oxide adduct obtained by the reaction reacts with ethyl chloride to obtain a nonionic surfactant fatty alcohol block polyether by a substitution reaction under the action of an alkaline catalyst. The high molecular compound component has extremely low foam, and the foaming force is less than 9mm. After being compounded with a chelating agent, an antibacterial agent and other components, a synergistic effect can be generated, which helps to significantly reduce the foaming force of the cleaning composition, and at the same time further enhances the stability and antibacterial performance of the product, thereby effectively improving the performance of the product. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the examples, but the present invention is not limited thereby. The experimental methods in the following examples are conventional methods unless otherwise specified.

[0029] Example 1 A low-foam machine washing composition based on a modified nonionic surfactant comprises the following components by mass percentage: 5% nonionic surfactant, 5% antibacterial agent, 5% chelating agent, 2% cosolvent, 2% auxiliary agent and the balance water.

[0030] The antibacterial agent is benzalkonium chloride, the chelating agent is methylglycine diacetate trisodium salt, the cosolvent is glycerol, the auxiliary agent is a preservative, and the nonionic surfactant is a fatty alcohol block polyether.

[0031] The preparation method of the fatty alcohol block polyether is as follows: (1) Fatty alcohol and aluminum perchlorate in an amount of 0.1% of fatty alcohol are put into a reaction kettle, the atmosphere in the kettle is replaced with nitrogen three times, and then ethylene oxide is added, the molar ratio of ethylene oxide to fatty alcohol is 2 mol:1 mol, and a ring-opening addition reaction is carried out at 100°C and 0.1 MPa to form fatty alcohol polyoxyethylene ether; (2) Adding fatty alcohol polyoxyethylene ether into a reaction kettle, dehydrating at 100°C for 1 hour under a vacuum degree of ≥0.095 MPa, and then adding propylene oxide for ring-opening addition to form fatty alcohol propylene oxide adduct, wherein the molar ratio of propylene oxide to fatty alcohol is 1 mol:1 mol. After the reaction is completed, post-treatment is performed to remove aluminum perchlorate; (3) The propylene oxide adduct was placed in a reactor, mixed evenly with sodium hydroxide under anaerobic conditions, and dehydrated at 100°C and a stirring speed of 300 rpm for 1 hour; (4) The mixture is cooled to 90°C, and ethyl chloride is added to carry out ethylation reaction. The molar ratio of fatty alcohol propylene oxide adduct, sodium hydroxide and ethyl chloride is 1 mol:5 mol:5 mol. After the reaction is completed, desalination treatment is carried out to obtain fatty alcohol block polyether.

[0032] A specific preparation method of a low-foam machine washing composition based on a modified nonionic surfactant comprises the following steps: S1: Add some water, nonionic surfactant and cosolvent into a stirring pot and stir evenly; S2: Add the remaining water, antibacterial agent and chelating agent, stir evenly and adjust the pH to 6.5; S3: Finally, add the remaining auxiliary agents and stir evenly to obtain a low-foam machine-washable floor cleaning composition.

[0033] Example 2 A low-foam machine washing composition based on a modified nonionic surfactant comprises the following components by mass percentage: 10% of a nonionic surfactant, 8% of an antibacterial agent, 10% of a chelating agent, 5% of a cosolvent, 5% of an auxiliary agent, and the balance of water.

[0034] The antibacterial agent is didecyl dimethyl ammonium chloride, the chelating agent is an aminocarboxylic acid compound, the cosolvent is propylene glycol, the auxiliary agent is essence, and the nonionic surfactant is fatty alcohol block polyether.

[0035] The preparation method of the fatty alcohol block polyether is as follows: (1) Fatty alcohol and magnesium perchlorate in an amount of 0.3% of fatty alcohol are put into a reaction kettle, the atmosphere in the kettle is replaced with nitrogen three times, and then ethylene oxide is added, the molar ratio of ethylene oxide to fatty alcohol is 2.5 mol:1 mol, and a ring-opening addition reaction is carried out at 110°C and 0.2 MPa to form fatty alcohol polyoxyethylene ether; (2) Adding fatty alcohol polyoxyethylene ether into a reaction kettle, dehydrating at 110°C for 1.5 h under a vacuum degree of ≥0.095 MPa, and then adding propylene oxide for ring-opening addition to form fatty alcohol propylene oxide adduct, wherein the molar ratio of propylene oxide to fatty alcohol is 1.5 mol:1 mol. After the reaction is completed, post-treatment is performed to remove magnesium perchlorate; (3) The propylene oxide adduct was placed in a reactor, mixed evenly with potassium hydroxide under anaerobic conditions, and dehydrated at 110°C and a stirring speed of 400 rpm for 1.5 h; (4) The mixture is cooled to 95°C, and ethyl chloride is added to carry out ethylation reaction. The molar ratio of fatty alcohol propylene oxide adduct, potassium hydroxide and ethyl chloride is 1 mol:5.5 mol:5.5 mol. After the reaction is completed, desalination treatment is carried out to obtain fatty alcohol block polyether.

[0036] A specific preparation method of a low-foam machine washing composition based on a modified nonionic surfactant comprises the following steps: S1: Add some water, nonionic surfactant and cosolvent into a stirring pot and stir evenly; S2: Add the remaining water, antibacterial agent and chelating agent, stir evenly and adjust the pH to 6.8; S3: Finally, add the remaining auxiliary agents and stir evenly to obtain a low-foam machine-washable floor cleaning composition.

[0037] Example 3 A low-foam machine washing composition based on a modified nonionic surfactant comprises the following components by mass percentage: 20% of a nonionic surfactant, 10% of an antibacterial agent, 15% of a chelating agent, 10% of a cosolvent, 10% of an auxiliary agent, and the balance of water.

[0038] The antibacterial agent is polyhexamethylene biguanide hydrochloride, the chelating agent is an organic aminophosphonic acid compound, the cosolvent is isohexanediol, the auxiliary agent is a pigment, and the nonionic surfactant is a fatty alcohol block polyether.

[0039] The preparation method of the fatty alcohol block polyether is as follows: (1) Fatty alcohol and zinc perchlorate in an amount of 0.5% of fatty alcohol are put into a reaction kettle, the atmosphere in the kettle is replaced with nitrogen three times, and then ethylene oxide is added, the molar ratio of ethylene oxide to fatty alcohol is 3 mol:1 mol, and a ring-opening addition reaction is carried out at 120°C and 0.3 MPa to form fatty alcohol polyoxyethylene ether; (2) Adding fatty alcohol polyoxyethylene ether into a reaction kettle, dehydrating at 120°C for 2 hours under a vacuum degree of ≥0.095 MPa, and then adding propylene oxide for ring-opening addition to form fatty alcohol propylene oxide adduct, wherein the molar ratio of propylene oxide to fatty alcohol is 2 mol:1 mol. After the reaction is completed, post-treatment is performed to remove zinc perchlorate; (3) The propylene oxide adduct is placed in a reactor, mixed evenly with sodium methoxide under anaerobic conditions, and dehydrated at 120°C with a stirring speed of 500 rpm for 2 h; (4) The mixture is cooled to 100°C, and ethyl chloride is added to carry out ethylation reaction. The molar ratio of fatty alcohol propylene oxide adduct, sodium methoxide and ethyl chloride is 1 mol:6 mol:6 mol. After the reaction is completed, desalination treatment is carried out to obtain fatty alcohol block polyether.

[0040] A specific preparation method of a low-foam machine washing composition based on a modified nonionic surfactant comprises the following steps: S1: Add some water, nonionic surfactant and cosolvent into a stirring pot and stir evenly; S2: Add the remaining water, antibacterial agent, and chelating agent, stir evenly, and adjust the pH to 7.0; S3: Finally, add the remaining auxiliary agents and stir evenly to obtain a low-foam machine-washable floor cleaning composition.

[0041] Comparative Example 1: This comparative example 1 is substantially the same as Example 2, except that step (2) is omitted in the process of fatty alcohol block polyether.

[0042] Comparative Example 2: This comparative example 2 is basically the same as Example 2, except that step (3) is omitted in the process of fatty alcohol block polyether.

[0043] Comparative Example 3: This comparative example 2 is substantially the same as Example 2, except that step (4) is omitted in the process of fatty alcohol block polyether.

[0044] Test experiment: The floor cleaning composition samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated by the following method.

[0045] 1. Antibacterial rate test: refer to "QB / T2738 Evaluation Method for Antibacterial and Antimicrobial Effects of Daily Chemical Products".

[0046] 2. Detergency test: refer to "QB / T4532-2013 Hard Floor Cleaner Evaluation Method".

[0047] 3. Stability test: Bottle the sample, seal it and place it in a 45°C oven for 4 weeks. Return it to room temperature and observe its appearance.

[0048] 4. Foaming power test method: Prepare the sample into a 2g / L solution with tap water, take 20mL into a 100mL stoppered measuring cylinder, cover with a ground-mouth stopper, and oscillate up and down vigorously for 10 times (one round trip), and record the foam height when the oscillation is completed.

[0049] The experimental results are shown in Table 1: Table 1 Performance test results of floor cleaning composition samples sample Antibacterial rate Detergency stability Foaming force (mm) Example 1 96.02% 95.52% No change 6 Example 2 97.34% 96.04% No change 5 Example 3 96.52% 95.31% No change 8 Comparative Example 1 90.13% 91.51% Layering 72 Comparative Example 2 92.85% 92.78% turbid 51 Comparative Example 3 88.44% 89.54% turbid 55 The present invention provides a low-foam machine washing composition based on a modified nonionic surfactant, wherein the nonionic surfactant containing a fatty alcohol block polyether is obtained by successively subjecting a fatty alcohol to a ring-opening addition reaction with ethylene oxide and propylene oxide, and then to a substitution reaction with ethyl chloride, and the component has extremely low foam. It can be seen from Table 1 that the foaming power of the samples of the embodiment is less than 9 mm, which is significantly higher than that of the comparative example, and the detergency, stability and antibacterial performance of the samples are also slightly higher than those of the comparative example. In comparative example 1, no ring-opening addition reaction with propylene oxide is performed, so a fatty alcohol polyether is obtained, and the foaming power of the product cannot be significantly reduced. Similarly, since comparative example 2 does not have the dehydration pretreatment of step (3) and comparative example 3 does not introduce a branched alkyl group through a substitution reaction, the foaming power of the surfactant obtained is not significantly reduced, and the antibacterial performance and stability are not as good as those of the embodiment.

[0050] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A low-foam machine washing composition based on a modified nonionic surfactant, characterized in that: Calculated by mass percentage, it includes the following components: 1% to 20% non-ionic surfactant, 1% to 10% antibacterial agent, 0.1% to 15% chelating agent, 0.1% to 10% cosolvent, 0.1% to 10% auxiliary agent, and the balance water.

2. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 1, characterized in that: The nonionic surfactant is a fatty alcohol block polyether, and the fatty alcohol block polyether is obtained by using a fatty alcohol as a starter and an acidic catalyst as an initiator, successively undergoing addition reactions with ethylene oxide and propylene oxide, and then undergoing a substitution reaction with ethyl chloride under the action of an alkaline catalyst.

3. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 2, characterized in that: The preparation method of the fatty alcohol block polyether is as follows: (1) The initiator and the acid catalyst are placed in a reaction kettle, the atmosphere in the kettle is replaced with nitrogen three times, and then ethylene oxide is added to form an intermediate 1 by ring-opening addition reaction; (2) intermediate 1 is placed in a reaction kettle, and after dehydration for 1 to 2 hours at a vacuum degree of ≥0.095 MPa and 100°C to 120°C, propylene oxide is added for ring-opening addition to form intermediate 2. After the reaction is completed, post-treatment is performed to remove the acidic catalyst; (3) The intermediate 2 is placed in a reaction kettle, mixed evenly with the alkaline catalyst under anaerobic conditions, and dehydrated for 1 to 2 hours at 100 to 120° C. and a stirring speed of 300 to 500° C.; (4) The mixture is cooled to 90-100°C, and ethyl chloride is added to carry out ethylation reaction. After the reaction is completed, desalination treatment is carried out to obtain fatty alcohol block polyether.

4. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 2, characterized in that: The fatty alcohol is one or more of C12-C18 isomeric fatty alcohols.

5. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 3, characterized in that: In the step (1), the acidic catalyst is one or more of aluminum perchlorate, magnesium perchlorate, and zinc perchlorate, the amount of the acidic catalyst added is 0.1% to 0.5% of the amount of the initiator substance, the molar ratio of ethylene oxide to the initiator is 2 to 3 mol:1 mol, the intermediate 1 is a fatty alcohol polyoxyethylene ether, the reaction temperature of the ring-opening addition is 100 to 120° C., and the reaction pressure is 0.1 to 0.3 MPa.

6. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 3, characterized in that: In the step (2), the molar ratio of propylene oxide to the initiator is 1-2 mol:1 mol, and the intermediate 2 is a fatty alcohol propylene oxide adduct.

7. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 3, characterized in that: The alkaline catalyst in step (3) is one or more of sodium hydroxide, potassium hydroxide, and sodium methoxide, and the alkaline catalyst is 0.1% to 0.5% of the mass of the intermediate 2; the molar ratio of the intermediate 2, the alkaline catalyst and ethyl chloride in step (3) and step (4) is 1 mol: 5 to 6 mol: 5 to 6 mol.

8. A low-foam machine washing composition based on a modified nonionic surfactant according to claim 1, characterized in that: The antibacterial agent is selected from one or more of benzalkonium chloride, didecyl dimethyl ammonium chloride, polyhexamethylene biguanide hydrochloride, and silver ions; the chelating agent is selected from one or more of methylglycine diacetate trisodium salt, aminocarboxylic acid compounds, organic aminophosphonic acid compounds, sodium citrate, ammonium citrate, and potassium sodium tartrate; the cosolvent is selected from one or more of glycerol, propylene glycol, isohexanediol, diethylene glycol butyl ether, and sorbitol; and the auxiliary agent is selected from one or more of preservatives, flavors, and pigments.

9. A method for preparing a low-foaming machine washing composition based on a modified nonionic surfactant according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: S1: Add some water, nonionic surfactant and cosolvent into a stirring pot and stir evenly; S2: Add the remaining amount of water, antibacterial agent, and chelating agent to adjust the pH to an appropriate range; S3: Finally, add the remaining auxiliary agents and stir evenly to obtain a low-foam machine-washable floor cleaning composition.

10. The method for preparing a low-foam machine washing composition based on a modified nonionic surfactant according to claim 9, characterized in that: The suitable range of pH adjustment in step S2 is 6.5 to 7.0.