A nonionic thickener and its preparation method, use, and concentrated laundry detergent

Abstract

The present application belongs to the technical field of thickener preparation, and discloses a method for preparing a nonionic thickener. The method first heats and esterifies AEO9, acrylic acid, and a catalyst to obtain a first esterification product, then adds a functional monomer to the first esterification product, heats and esterifies to obtain a second esterification product, and then adds AEO9 and an initiator to the second esterification product and heats to obtain a nonionic thickener, wherein the functional monomer is a hydrophilic unsaturated monomer containing a hydrophilic group and an unsaturated bond and / or a cationic unsaturated monomer containing a double unsaturated bond, the hydrophilic group in the hydrophilic unsaturated monomer is a hydroxyl group, and the initiator is selected from a solution of at least one of ammonium persulfate, sodium persulfate, benzoyl peroxide, and sodium metabisulfite. Through the above design, the present application enables the thickener to significantly improve the viscosity of the laundry detergent in the use scenario of high concentration AEO9. In addition, the present application also discloses a nonionic thickener and its use, and a concentrated laundry detergent.

Description

Technical Field

[0001] The invention relates to the technical field of thickener preparation, and in particular to a nonionic thickener and a preparation method, application and concentrated laundry detergent thereof. Background Art

[0002] Fatty alcohol polyoxyethylene ether is a typical nonionic surfactant with good wetting, emulsification, dispersion, penetration, solubilization and other functions, and is widely used. Among them, AEO9 is widely used in daily chemical cleaning products because of its more outstanding detergency, but at the same time, after it is compounded into the washing system, the viscosity of the system will drop rapidly, especially for some AEO9 with a relatively high addition amount. The traditional coping method is generally to add inorganic salts, high molecular organic matter or compound with anionic surfactants and then use inorganic acid to thicken. These thickening methods can work when the amount of AEO9 added is small, but as the amount of AEO9 increases, the thickening effect is not obvious. The active matter in ordinary detergents is generally >15%, and 1-5% AEO9 is generally added at this time; the active matter in concentrated laundry detergents is generally required to be >25%, and AEO9 generally accounts for a higher proportion. Therefore, in concentrated laundry detergents, there are higher requirements for the thickening ability of thickeners.

[0003] At the same time, the traditional synthesis method of poly (fatty alcohol) polyoxyethylene ether acrylate is to esterify fatty alcohol polyoxyethylene ether with excess acrylic acid at 100-160°C to synthesize fatty alcohol polyoxyethylene ether acrylate, then remove excess acrylic acid, and polymerize under the action of an initiator to obtain poly (fatty alcohol) polyoxyethylene ether acrylate. Traditional synthesis methods all require the addition of inhibitors during the esterification process, of which the most effective inhibitor is hydroquinone. Hydroquinone is difficult to remove in the later stage, and is harmful to the human body (clearly a banned component in the cosmetics catalog +), and will turn pink when it encounters alkaline substances or is oxidized by air during use, which will have a certain impact on the appearance of the detergent. At the same time, in actual production, when the esterification temperature reaches the boiling point of acrylic acid, there is no inhibitor in the gas phase acrylic acid, and polymerization is also likely to occur.

[0004] Chinese patent application 201811252679.8 discloses a nonionic polymer surfactant and a synthesis method thereof, the method comprising the following steps:

[0005] (1) Add fatty alcohol polyoxyethylene ether and acrylic acid into a reactor connected to a vacuum device, add a catalyst and an inhibitor, and react for 3-8 hours under stirring conditions at 60-100° C. and a vacuum degree of 0.01-0.06 MPa to carry out an esterification reaction.

[0006] (2) After the esterification reaction is completed, the reaction pressure is increased and the unreacted acrylic acid is distilled off to obtain the intermediate product fatty alcohol polyoxyethylene ether acrylate.

[0007] (3) adding the intermediate product, deionized water and initiator into a reaction vessel, and carrying out a solution polymerization reaction at 60-120° C. for 2-6 hours. After the reaction is completed, a nonionic polymer surfactant poly(fatty alcohol) polyoxyethylene ether acrylate is obtained.

[0008] This scheme uses water as the solvent in solution polymerization to homopolymerize fatty alcohol polyoxyethylene ether acrylate (only one monomer undergoes polymerization reaction), so that the system has low viscosity, easy heat transfer and mixing, and easy temperature control; and the intermediate product, deionized water and initiator are added to a reaction container, and the solution polymerization reaction is carried out at 60-120° C. The polymerization time is 2-6 hours. After the reaction is completed, the non-ionic polymer surfactant polyoxyethylene alcohol ether acrylate is obtained.

[0009] At the same time, this solution adjusts the molecular weight and molecular weight distribution of the product by controlling the monomer concentration and the amount of initiator used, but it should be noted that this solution still does not avoid or omit the use of inhibitors.

[0010] The problem to be solved by this scheme is: how to provide a method for preparing a nonionic thickener without using an inhibitor during the preparation process. Summary of the invention

[0011] The object of the present invention is to provide a method for preparing a nonionic thickener which can maintain a good thickening effect of the nonionic thickener without using a polymerization inhibitor.

[0012] To achieve the above object, the present application discloses a method for preparing a nonionic thickener, comprising the following steps:

[0013] Step 1: heating and esterifying AEO9, acrylic acid and a catalyst to obtain a first esterification product;

[0014] Step 2: adding a functional monomer to the first esterification product obtained in step 1, heating and esterification to obtain a second esterification product;

[0015] Step 3: Add AEO9 and an initiator to the second esterification product obtained in step 2 and heat to obtain a nonionic thickener;

[0016] The functional monomer is a hydrophilic unsaturated monomer containing a hydrophilic group and an unsaturated bond and / or a cationic unsaturated monomer containing a diunsaturated bond, and the hydrophilic group in the hydrophilic unsaturated monomer is a hydroxyl group;

[0017] The initiator is selected from at least one of ammonium persulfate, sodium persulfate, benzoyl peroxide and sodium pyrosulfite.

[0018] Furthermore, the functional monomer is selected from at least one of allyl polyethylene glycol, allyl glycidyl ether, PEG diacrylate, 2-propoxylated neopentyl glycol diacrylate, and dimethyl diallyl ammonium chloride.

[0019] It should be noted that among the above-mentioned functional monomers, polymer-type additives such as allyl polyethylene glycol (APEG), allyl glycidyl ether, PEG diacrylate and other substances, in actual applications, the above-mentioned polymers with different molecular weights can be used as additives. At the same time, in actual applications, we recommend the use of APEG with a molecular weight of 400 to 1000, allyl glycidyl ether with a molecular weight of 300 to 500, and PEG diacrylate with a molecular weight of 200 to 600.

[0020] Preferably, step 1 is specifically:

[0021] AEO9, acrylic acid and a catalyst are mixed, heated and the system temperature is maintained between 140 and 150° C. and kept warm for 0.8 to 1.2 hours to obtain a first esterification product;

[0022] The molar ratio of AEO9 to acrylic acid is 1:2-3;

[0023] The ratio of the mass of the catalyst to the total mass of AEO9 and acrylic acid is 0.5 to 1:100;

[0024] The catalyst is selected from at least one of p-toluenesulfonic acid, concentrated sulfuric acid, dodecylbenzenesulfonic acid and hypophosphorous acid.

[0025] Preferably, step 2 is specifically:

[0026] The temperature of the first esterification product obtained in step 1 is maintained between 120° C. and 130° C., and then a functional monomer is added to the first esterification product, followed by heat preservation for 0.3 to 0.8 hours to obtain a second esterification product;

[0027] The molar ratio of the functional monomer to AEO9 in step 1 is 0.8-1.2:10.

[0028] Preferably, step 3 specifically comprises: adding AEO9 and an initiator to the second esterification product obtained in step 2, and then heating to 90-100° C. for 1.5-3 hours to obtain a nonionic thickener;

[0029] The mass ratio of AEO9 in step 3 to AEO9 in step 1 is 5 to 7:10.

[0030] Preferably, the functional monomer is dimethyldiallylammonium chloride, allyl glycidyl ether, or PEG diacrylate.

[0031] In addition, the present application also discloses a nonionic thickener, which is prepared by the above-mentioned preparation method of the nonionic thickener.

[0032] Preferably, the viscosity is 7500-16000 cp.

[0033] In addition, the present application also discloses the use of the nonionic thickener as a thickening component and / or active ingredient of concentrated laundry detergent.

[0034] In addition, the present application also discloses a concentrated laundry detergent containing 50-60 wt % of the above-mentioned nonionic thickener.

[0035] The beneficial effects of this application are:

[0036] For non-ionic systems, non-ionic thickening effects are generally poor; in order to thicken in this system, it is necessary to rely on the sample's own viscosity, hydrogen bond thickening, and neutralization thickening. The HLB of the AEO-9 used is 12-13. After the synthesis of fatty alcohol polyoxyethylene ether acrylate, the molecular weight is large and the hydrophilicity is slightly reduced. Therefore, it is necessary to polymerize with hydrophilic monomers to synthesize polymers with P-AEO9-AA as the main body. The more oxygen on the hydrophilic group of the molecule, the more hydrogen bonds can be formed with water, the better the water solubility, the greater the degree of hydrogen bond thickening, and the greater the consistency. After the functional monomer is connected and the alkaline substance is added, the polymer is neutralized into salt, and ions are generated after ionization, which causes the negative charge generated on the main molecular chain of the polymer. The "like attracts, opposites repel" of the charges in the system further promotes the extension of the polymer molecular chain to form a network structure. The polymer molecules expand rapidly to produce viscosity, and the viscosity of the system increases instantly to achieve the desired effect of the product. DETAILED DESCRIPTION

[0037] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. In the description of the present invention, it should be noted that, if no specific conditions are specified in the embodiments, the conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0038] Example 1

[0039] Step 1: 100 g AEO9, 26.67 g acrylic acid, and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0040] Step 2: Add dimethyldiallyl ammonium chloride to the first esterification product obtained in step 1 and maintain the temperature of the system at 120° C. to 130° C. for 0.5 h to obtain a second esterification product, wherein the molar ratio of dimethyldiallyl ammonium chloride to AEO9 in step 1 is 1:10;

[0041] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0042] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0043] Example 2

[0044] Step 1: 100 g AEO9, 24.74 g acrylic acid and 0.62 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1.2 h to obtain the first esterification product;

[0045] Step 2: Add dimethyldiallyl ammonium chloride to the first esterification product obtained in step 1 and maintain the temperature of the system at 120° C. to 130° C. for 0.3 h to obtain a second esterification product, wherein the molar ratio of dimethyldiallyl ammonium chloride to AEO9 in step 1 is 0.8:10;

[0046] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 100° C. for 1.5 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0047] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0048] Example 3

[0049] Step 1: 100 g AEO9, 37.11 g acrylic acid and 1.37 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 0.8 h to obtain the first esterification product;

[0050] Step 2: Add dimethyldiallyl ammonium chloride to the first esterification product obtained in step 1 and maintain the system temperature between 120° C. and 130° C. for 0.8 h to obtain a second esterification product, wherein the molar ratio of dimethyldiallyl ammonium chloride to AEO9 in step 1 is 1.2:10;

[0051] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 95° C. for 2 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0052] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0053] Example 4

[0054] The method is substantially the same as Example 1, except that the same molar amount of allyl polyethylene glycol is used instead of dimethyldiallylammonium chloride.

[0055] Example 5

[0056] The method is substantially the same as Example 1, except that the same molar amount of PEG diacrylate is used instead of dimethyldiallylammonium chloride.

[0057] Example 6

[0058] The method is basically the same as Example 1, except that a mixture of allyl polyethylene glycol, PEG diacrylate and dimethyl diallyl ammonium chloride in equal molar amounts is used instead of dimethyl diallyl ammonium chloride, and the molar ratio of allyl polyethylene glycol, PEG diacrylate and dimethyl diallyl ammonium chloride is 1:1:1.

[0059] Example 7

[0060] A mixture of 2-propoxylated neopentyl glycol diacrylate, PEG diacrylate and dimethyldiallylammonium chloride in the same molar amount is used to replace dimethyldiallylammonium chloride, and the molar ratio of 2-propoxylated neopentyl glycol diacrylate, PEG diacrylate and dimethyldiallylammonium chloride is 1:1:1.

[0061] Example 8

[0062] It is basically the same as Example 1, except that in step 3, the mass ratio of AEO9 in step 3 to AEO9 in step 1 is 5:10.

[0063] Example 9

[0064] The method is basically the same as Example 1, except that the mass ratio of AEO9 in step 3 to that in step 1 is 7:10.

[0065] Example 10

[0066] Step 1: 100 g AEO9, 12.37 g acrylic acid and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0067] Step 2: Add dimethyldiallyl ammonium chloride to the first esterification product obtained in step 1 and maintain the temperature of the system at 120° C. to 130° C. for 0.5 h to obtain a second esterification product, wherein the molar ratio of dimethyldiallyl ammonium chloride to AEO9 in step 1 is 1:10;

[0068] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0069] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0070] Embodiment 11

[0071] Step 1: 100 g AEO9, 49.48 g acrylic acid and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0072] Step 2: Add dimethyldiallyl ammonium chloride to the first esterification product obtained in step 1 and maintain the temperature of the system at 120° C. to 130° C. for 0.5 h to obtain a second esterification product, wherein the molar ratio of dimethyldiallyl ammonium chloride to AEO9 in step 1 is 1:10;

[0073] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0074] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0075] Comparative Example 1

[0076] Step 1: 100 g AEO9, 26.67 g acrylic acid and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0077] Step 2: Add AEO9 to the second esterification product obtained in step 1, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, and the mass ratio of AEO9 in step 3 to that in step 1 is 6:10.

[0078] Comparative Example 2

[0079] Step 1: 100 g AEO9, 26.67 g acrylic acid and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0080] Step 2: Add vinyl formate to the first esterification product obtained in step 1 and maintain the system temperature at 120° C. to 130° C. for 0.5 h to obtain a second esterification product, wherein the molar ratio of vinyl formate to AEO9 in step 1 is 1:10;

[0081] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0082] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0083] Comparative Example 3

[0084] Step 1: 100 g AEO9, 26.67 g acrylic acid and 0.89 g p-toluenesulfonic acid were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 1 hour to obtain the first esterification product;

[0085] Step 2: Add trimethyl (vinyl) ammonium chloride to the first esterification product obtained in step 1 and maintain the temperature of the system at 120° C. to 130° C. for 0.5 h to obtain a second esterification product, wherein the molar ratio of trimethyl (vinyl) ammonium chloride to AEO9 in step 1 is 1:10;

[0086] Step 3: Add AEO9 to the second esterification product obtained in step 2, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 3 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0087] Wherein, the mass ratio of ammonium persulfate in the ammonium persulfate solution to the second esterification product is 0.6:100.

[0088] Comparative Example 4

[0089] Step 1: 100 g AEO9, 26.67 g acrylic acid, 0.89 g p-toluenesulfonic acid and 0.08 g hydroquinone were mixed and added into a flask, and the temperature of the system was raised and maintained between 140 and 150° C. for 6 hours to obtain the first esterification product;

[0090] Step 2: Add AEO9 to the first esterification product obtained in step 1, dropwise add a 3% ammonium persulfate solution, and then heat to 90° C. for 2 hours to obtain a nonionic thickener, wherein the mass ratio of AEO9 in step 3 to that in step 1 is 6:10;

[0091] The mass ratio of ammonium persulfate to the first esterification product in the ammonium persulfate solution is 0.6:100.

[0092] Performance Test:

[0093] Thickening test: Mix AEO9 with thickener and sodium hydroxide evenly, then dilute it 6-8 times and test the sample viscosity at 25℃.

[0094] 2. Raw materials and specifications used in this method:

[0095] AEO9: BASF

[0096] Acrylic acid: Purity>99%

[0097] p-Toluenesulfonic acid: analytical grade

[0098] Polyethylene glycol: PETRONAS

[0099] Ammonium persulfate: analytical grade

[0100] The test results are shown in Table 1:

[0101] Table 1

[0102]

[0103]

[0104] Decontamination ability comparison

[0105] The nonionic thickeners prepared in the examples and comparative examples were diluted to a concentration of 2 g / L, and detergency tests were performed according to GB / T 13174-2021. The results are shown in Table 2:

[0106]

[0107]

[0108] Result analysis:

[0109] Application Examples 1-5

[0110] A concentrated laundry detergent containing 30% AEO9 was prepared, and the thickeners prepared in the examples and comparative examples were applied to the concentrated laundry detergent to compare the thickening effects at different dilution multiples;

[0111] The formulas of application examples 1-5 are shown in Table 2:

[0112] Table 2

[0113] Group Application Example 1 Application Example 2 Application Example 3 Application Example 4 Application Example 5 AEO-9 30％ 30％ 30％ 30％ 30％ Thickener prepared in Example 1 60％ 0 0 0 0 Thickener prepared in Comparative Example 1 0 60％ 0 0 0 Thickener prepared in Comparative Example 2 0 0 60％ 0 0 Thickener prepared in Comparative Example 3 0 0 0 60％ 0 Thickener prepared in Comparative Example 4 0 0 0 0 60％ 30% lye 10％ 10％ 10％ 10％ 10％

[0114] It should be noted that the 30% alkali solution in the formula is specifically a sodium hydroxide aqueous solution with a mass fraction of sodium hydroxide of 30%.

[0115] The thickening effects of application examples 1-5 at different dilution ratios are shown in Table 3:

[0116] Table 3

[0117]

[0118]

[0119] Result analysis:

[0120] 1. It can be seen from Examples 1-3 in Table 1 that a small adjustment in the amount of each component added during the preparation process will not have a significant effect on the viscosity and appearance;

[0121] At the same time, it can be seen from Table 2 that since a certain amount of AEO9 is added to the thickener itself, the thickener itself also has a certain thickening ability. It can be seen from Examples 1-3 that when the addition amount of each component is slightly adjusted, the thickener does not show an obvious change trend in the detergency.

[0122] 2. It can be seen from Example 1 and Examples 4-7 in Table 1 that when allyl polyethylene glycol and PEG diacrylate are used instead of dimethyldiallylammonium chloride, the viscosity, appearance, and decontamination ability of Examples 4-5 are not significantly different from those of Example 1;

[0123] When Examples 6 and 7 replace dimethyldiallyl ammonium chloride with a mixture of allyl polyethylene glycol, PEG diacrylate, and dimethyldiallyl ammonium chloride, or a mixture of 2-propoxy neopentyl glycol diacrylate, PEG diacrylate, and dimethyldiallyl ammonium chloride, the viscosity of Example 7 is improved to a certain extent, but it is relatively weak, while Example 6 has achieved a significant improvement. It can be seen that on the one hand, the replacement of dimethyldiallyl ammonium chloride with a mixture of allyl polyethylene glycol, PEG diacrylate, and dimethyldiallyl ammonium chloride can significantly improve the viscosity and detergency of the thickener itself. On the other hand, the difference between Example 7 and Example 6 is only reflected in the use of allyl polyethylene glycol. It can be seen that not all functional monomers can improve the performance of the thickener, and the result obtained in Example 6 is beyond expectations.

[0124] 3. It can be seen from Example 1 and Comparative Example 1 that when no functional monomer is added, the thickener cannot maintain good self-viscosity and detergency. Further observation of Comparative Example 2 and Comparative Example 3 shows that not all monomers with hydrophilic groups or containing diunsaturated bonds can achieve the improvement of the viscosity of the thickener.

[0125] Further observation of Comparative Example 4 shows that although the thickener in Comparative Example 4 has good thickening viscosity by adding the polymerization inhibitor, on the one hand, the use of the polymerization inhibitor will reduce the appearance transparency of the thickener. On the other hand, observation of Table 3 shows that the thickener with the polymerization inhibitor added has an improved viscosity after dilution compared with other application examples in the use scenario of high-concentration AEO9, but it cannot improve the viscosity of the finished product after dilution with water as in Example 1. At the same time, Application Example 5 with the polymerization inhibitor added presents a pink color, which undoubtedly increases the difficulty of color adjustment in the subsequent production process.

Claims

1. A method for preparing a nonionic thickener, characterized in that: The following steps are involved: Step 1: heating and esterifying AEO9, acrylic acid and a catalyst to obtain a first esterification product; Step 2: maintaining the temperature of the first esterification product obtained in step 1 at 120-130° C., then adding a functional monomer to the first esterification product, and then keeping the temperature for 0.3-0.8 hours to obtain a second esterification product; Step 3: Add AEO9 and an initiator to the second esterification product obtained in step 2 and heat to obtain a nonionic thickener; The functional monomer is selected from at least one of allyl polyethylene glycol, allyl glycidyl ether, PEG diacrylate, 2-propoxy neopentyl glycol diacrylate, and dimethyl diallyl ammonium chloride; The initiator is selected from at least one of ammonium persulfate, sodium persulfate, benzoyl peroxide and sodium pyrosulfite.

2. The method for preparing a nonionic thickener according to claim 1, characterized in that: Step 1 is as follows: AEO9, acrylic acid and a catalyst are mixed, heated and the system temperature is maintained between 140 and 150° C. and kept warm for 0.8 to 1.2 hours to obtain a first esterification product; The molar ratio of AEO9 to acrylic acid is 1:2-3; The ratio of the mass of the catalyst to the total mass of AEO9 and acrylic acid is 0.5 to 1:100; The catalyst is selected from at least one of p-toluenesulfonic acid, concentrated sulfuric acid, dodecylbenzenesulfonic acid and hypophosphorous acid.

3. The method for preparing a nonionic thickener according to claim 1, characterized in that: The molar ratio of the functional monomer to AEO9 in step 1 is 0.8-1.2:

10.

4. The method for preparing a nonionic thickener according to claim 1, characterized in that: Step 3 specifically comprises: adding AEO9 and an initiator to the second esterification product obtained in step 2, and then heating to 90-100° C. and keeping the temperature for 1.5-3 hours to obtain a nonionic thickener; The mass ratio of AEO9 in step 3 to AEO9 in step 1 is 5 to 7:

10.

5. The method for preparing a nonionic thickener according to claim 1, characterized in that: The functional monomers are dimethyldiallylammonium chloride, allyl glycidyl ether and PEG diacrylate.

6. A nonionic thickener, characterized in that: The invention is prepared by the preparation method of the nonionic thickener according to any one of claims 1 to 5.

7. The nonionic thickener according to claim 6, characterized in that The viscosity is 7500~16000cp.

8. Use of the nonionic thickener as claimed in any one of claims 6 to 7 as a thickening component and / or active ingredient of concentrated laundry detergent.

9. A concentrated laundry detergent, characterized in that: Contains 50-60 wt % of the nonionic thickener as claimed in claim 6.

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