Multi-layer low-foam detergent tablet and preparation method therefor

Abstract

The present application relates to a multi-layer low-foam detergent tablet and a preparation method therefor. A multi-layer low-foam detergent tablet, consisting of two or more single-layer detergent tablets by means of self-bonding, wherein at least one single-layer detergent tablet is a single-layer detergent tablet A, which is prepared from a slurry A. The slurry A comprises: a film-forming agent A, an anionic surfactant A, a non-ionic surfactant, an acidulant, a chelating agent, an enzyme preparation A, an auxiliary agent A, a fragrance A, and water. The multi-layer low-foam detergent tablet of the present application is characterized by high detergency, low foam, fast dissolution, etc.

Description

A multilayer low-foaming detergent sheet and its preparation method Technical Field

[0001] This application relates to the field of detergent tablets, and more specifically, to a multilayer low-foaming detergent tablet and a method for its preparation. Background Technology

[0002] Currently, laundry pods and sheets are popular among consumers due to their convenience, as they are dispensed in measured quantities. A single laundry pod can weigh up to 20g, while a single laundry sheet weighs an average of 4g. Therefore, in actual use, compared to laundry pods, laundry sheets have limited cleaning power because a single sheet can only hold a limited amount of surfactant. The most direct way to solve this problem is to use multiple laundry sheets.

[0003] While using multiple laundry sheets at the same time or using a single multi-layered laundry sheet can bring beneficial effects to cleaning power, the total active ingredient content increases many times, which also increases the amount of foam. During use, the foam is more likely to overflow from the washing machine, increasing the number of rinses and the amount of water used.

[0004] In the preparation of tablet slurries, a certain level of foaming and foaming properties is required, while the finished product needs to be low-foaming and easy to rinse. This characteristic means that the problem of excessive foam caused by high total active ingredients cannot be solved by directly adding defoamers or using low-foaming surfactants.

[0005] In summary, there is an urgent need to develop a multi-layer, low-foaming detergent sheet with high cleaning power. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a multilayer low-foaming detergent sheet and its preparation method. The multilayer low-foaming detergent sheet features high cleaning power, low foaming, and fast dissolution time.

[0007] In a first aspect, this application provides a multilayer low-foaming detergent sheet, employing the following technical solution: A multilayer low-foaming detergent sheet is composed of two or more single-layer detergent sheets bonded together by self-adhesion; wherein, at least one single-layer detergent sheet is a single-layer detergent sheet A; the single-layer detergent sheet A is prepared from slurry A, and according to the weight percentage of slurry A, it includes the following raw materials: 10-30% film-forming agent A, 20-50% anionic surfactant A, 5-20% nonionic surfactant, 2-10% acidifier, 0.5-3% chelating agent, 0-5% enzyme preparation A, 1-5% auxiliary agent A, 0.5-5% fragrance A, and water; film-forming agent A includes polyvinyl alcohol; anionic surfactant A includes high-foaming surfactant and low-foaming surfactant; the weight ratio of high-foaming anionic surfactant to low-foaming anionic surfactant is (3-10):1; the high-foaming anionic surfactant includes at least one of sodium α-alkenyl sulfonate, sodium fatty acid methyl ester sulfonate, and sodium lauroyl glutamate; Low-foaming anionic surfactants include at least one of sodium isomeric alcohol ether sulfate, sodium fatty acid methyl ester ethoxylated sulfonate, and sodium isooctyl sulfate; nonionic surfactants include at least two of EO / PO block polyethers, fatty acid methyl ester ethoxy compounds, secondary alcohol ethoxy compounds, and alkyl glycoside alkoxy compounds.

[0008] Alkyl glycoside alkoxy compounds, secondary alcohol ethoxy compounds, and fatty acid methyl ester ethoxy compounds have weak interactions between their hydrophilic and lipophilic groups, making them less prone to forming large amounts of foam. Fatty acid methyl ester ethoxylated sulfonates and modified oil ethoxy compounds (sodium sulfonate) possess both anionic and nonionic properties, classifying them as anionic-nonampholytic surfactants. The introduction of sulfonic acid groups enhances their molecular polarity, making them more readily interact with water molecules in solution, further reducing foam formation. In solution, their molecules can form stable micelle structures, and the interactions between these micelles are weak, making them less likely to generate large amounts of foam.

[0009] In EO / PO block polyethers, the polyoxyethylene groups are hydrophilic and the polyoxypropylene groups are lipophilic. This structure makes EO / PO block polyethers more likely to form micelles in aqueous solutions, resulting in higher surface tension. Simultaneously, the alternating arrangement of hydrophilic and lipophilic groups creates spatial barriers and numerous voids between the liquid films, weakening the film's strength and making the resulting foam film walls more prone to rupture.

[0010] This application uses a high-foaming surfactant as the main surfactant, combined with a specific low-foaming surfactant. Through the synergistic effect of the two types of surfactants, on the one hand, a certain amount of dense foam can be generated during the preparation of the slurry, ensuring the thickness and abundant pores of the multi-layer detergent sheet. When the multi-layer detergent sheet is used, water molecules can enter the interior of the sheet through the pores, thereby accelerating the dissolution rate. On the other hand, the multi-layer low-foaming detergent sheet prepared in this application not only has low foam volume but also fast defoaming rate, which can reduce the number of rinsing cycles and water consumption, which is of great significance for energy conservation and emission reduction. At the same time, it also ensures high detergency and has a variety of excellent properties.

[0011] Preferably, the weight ratio of the anionic surfactant A to the nonionic surfactant is (2-10):1.

[0012] Preferably, the chelating agent includes at least one of citric acid, gluconic acid, glutamic acid diacetic acid, and methylglycine diacetic acid.

[0013] Preferably, enzyme preparation A includes liquid and / or solid formulations.

[0014] Preferably, enzyme preparation A includes at least one of protease, amylase, lipase, cellulase, phosphodiesterase, pectinase, and mannanase.

[0015] Preferably, additive A includes C3-C18 polyols.

[0016] Preferably, the C3-C18 polyol includes at least one of glycerol, glycerol, butylene glycol, hexanediol, and octanediol.

[0017] Preferably, the single-layer detergent sheet further includes a single-layer detergent sheet B, which is prepared from slurry B and comprises the following raw materials by weight percentage: 3-20% film-forming agent B, 10-30% anionic surfactant B, 5-10% softener, 2-10% alkalizing agent, 0-5% enzyme preparation B, 1-5% auxiliary agent B, 0.5-5% fragrance B, and water; the film-forming agent B includes at least sodium alginate and carboxymethyl cellulose, with a weight ratio of sodium alginate to carboxymethyl cellulose of (1-15):1; the anionic surfactant B includes at least one of sodium α-alkenyl sulfonate, sodium alkyl sulfate, modified oil ethoxylate sulfonate, and sodium fatty acid methyl ester sulfonate.

[0018] Preferably, the sodium alkyl sulfate includes at least one of sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, sodium octadecyl sulfate, and sodium eicosyl sulfate.

[0019] Preferably, the acidifier comprises C12-C18 fatty acids.

[0020] Preferably, the C12-C18 fatty acids include at least one of lauric acid, oleic acid, stearic acid, and palmitic acid.

[0021] Preferably, the alkalizing agent includes at least one of sodium hydroxide / potassium, sodium carbonate / potassium, and sodium citrate / potassium.

[0022] By adopting the above technical solution, since single-layer detergent sheet A contains fatty acids and single-layer detergent sheet B contains an alkalizing agent, when single-layer detergent sheet A and single-layer detergent sheet B self-adhere, a fatty acid salt "saponification layer" will slowly form between the layers at high temperature, further promoting the self-adhesion between the layers. When the multi-layer detergent sheets dissolve in water, the fatty acid salts can form a film layer similar to mineral oil on the liquid surface, further reducing surface tension and thus inhibiting foam generation. At the same time, they can also interact with the liquid molecules inside the foam, causing the foam to break down and destroying its stability.

[0023] Adding fatty acid salts directly to the slurry can affect the foaming properties of the slurry. Therefore, forming a "saponification layer" of fatty acid salts during the preparation of multi-layer detergent tablets can avoid the above problems and further reduce the amount of foam generated during the use of multi-layer detergent tablets.

[0024] Preferably, the softener includes at least one of natural leaf silicate, hydrolyzed wheat protein / silicone copolymer, and amino silicone oil.

[0025] In this application, the specific categories of enzyme preparation B and adjuvant B are the same as those of enzyme preparation A and adjuvant A, respectively. Preferably, the single-layer washing sheet A is located in the outermost layer.

[0026] Preferably, the single-layer washing sheet A is located on the outermost layer, and the single-layer washing sheet B is located in the middle.

[0027] Preferably, the thickness of the single-layer washing sheet A is 0.3-3.5 mm, and the thickness of the single-layer washing sheet B is 0.3-3.0 mm.

[0028] Preferably, in the multi-layer low-foam detergent sheet, the layers of a single-layer detergent sheet are self-adhesive between the smooth surface of one layer and the rough surface of another layer.

[0029] Preferably, in the multilayer low-foaming detergent tablets, the solid formulations in enzyme preparation A and enzyme preparation B are preferably completely encapsulated between layers, and the liquid and solid formulations can be added separately from the same layer of detergent tablets.

[0030] Secondly, this application provides a method for preparing multilayer low-foaming detergent tablets, using the following technical solution: A method for preparing multilayer low-foaming detergent tablets includes the following steps: Step 1: Preparing slurry A, including the following steps: Step 1a: Mixing and stirring water and film-forming agent A at 75-85℃, and after the film-forming agent has swollen uniformly, adding anionic surfactant A and stirring to dissolve uniformly; Step 1b: Continuing to add the remaining raw materials of slurry A, stirring until uniform, to obtain slurry A; If slurry A contains enzyme preparation A, when enzyme preparation A contains liquid enzyme preparation, adding raw materials in step 1b, and cooling to 58-63℃ before adding liquid enzyme preparation to mix uniformly to obtain slurry A; when enzyme preparation A contains solid enzyme preparation, adding it in the form of spray during drying and tableting in step 3; Step 2: If it contains single-layer detergent tablets B, then preparing slurry B includes the following steps: Step 2a: Mixing water and film-forming agent B, and fully swelling to a homogeneous viscous liquid at 20-30℃; Step 2b: Under conditions of 38-45℃, add anionic surfactant B and auxiliary agent B and stir until dissolved evenly; Step 2c: Continue to add the remaining raw materials of slurry B to obtain slurry B; If slurry B contains enzyme preparation B, when enzyme preparation B contains liquid enzyme preparation, add liquid enzyme preparation in step 2b to mix evenly to obtain slurry B; When enzyme preparation B contains solid enzyme preparation, add it in the form of spray during drying and tableting in step 3; If it does not contain single-layer detergent tablets B, omit this step and proceed to step 3 after step 1; Step 3: During the drying and tableting stage of the slurry for preparing any single-layer detergent tablet, attach another single-layer or multi-layer detergent tablet that has completed the drying and forming stage, and continue drying until multi-layer low-foam detergent tablets are obtained.

[0031] When single-layer detergent sheets of the same type are self-adhesive, the semi-finished sheet in the drying stage has high viscosity and can bond tightly with another sheet. When single-layer detergent sheets A and B of different types are bonded together, due to the special "saponification layer" effect, they can also achieve the same tight bonding effect, resulting in multi-layer low-foam detergent sheets with good cleaning effect, low foaming, and fast dissolution.

[0032] In summary, this application has the following beneficial effects: 1. The low-foaming surfactants such as sodium isomeric alcohol ether sulfate used in this application not only reduce the amount of foam during the washing process but also accelerate the dissolution rate of the detergent sheet. Furthermore, the combined use of specially selected nonionic surfactants, anionic surfactants, and film-forming agents results in a single-layer detergent sheet with a rich porous structure, ensuring that the detergent sheet has a certain thickness while maintaining a low-foaming effect.

[0033] 2. When the multi-layer detergent tablets dissolve in water, the fatty acid salts can form a film similar to mineral oil on the liquid surface, further reducing surface tension and promoting dissolution. Attached Figure Description

[0034] Figure 1 is a cross-sectional microscope image of the double-layer low-foaming washing tablet of Example 1.

[0035] Figure 2 is a cross-sectional microscope image of the three-layer low-foaming detergent sheet of Example 3.

[0036] Figure 3 is a physical image of the three-layer low-foam detergent sheet of Example 3.

[0037] Figure 4 is a cross-sectional microscope image of the four-layer low-foaming detergent sheet of Example 6.

[0038] Figure 5 is a photograph of a single-layer detergent sheet A1, which is a comparative example of the double-layer low-foam detergent sheet.

[0039] Figure 6 shows the case where the single-layer washing sheet B prepared in Comparative Example 7 could not be formed.

[0040] Figure 7 shows the results of the storage stability test of the double-layer washing tablets of Comparative Examples 1-3.

[0041] Figure 8 shows the results of the storage stability test of the double-layer washing tablets of Comparative Examples 4-6 and Comparative Example 8.

[0042] Figure 9 shows the test results of Examples 1-3 at 0 min and 5 min in foam height detection.

[0043] Figure 10 shows the test results of Examples 4-6 at 0 min and 5 min in foam height detection.

[0044] Figure 11 shows the test results of Comparative Examples 1 and 4-5 at 0 min and 5 min in foam height detection.

[0045] Figure 12 shows the test results of Comparative Example 6 at 0 min and 5 min in foam height detection. Detailed Implementation

[0046] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] The raw materials used in the following examples and comparative examples are all commercially available products.

[0048] The following are the sources of some raw materials: Alkyl glycoside alkoxy compounds were purchased from the China Daily Chemical Research Institute, model APG-NF.

[0049] Sodium isomeric alcohol ether sulfate was purchased from the China Daily Chemical Research Institute, model number CYS-221.

[0050] The modified oil ethoxylated compound sodium sulfonate was purchased from the China Daily Chemical Research Institute, model SNS-80.

[0051] The hydrolyzed wheat protein / silicone copolymer was purchased from Croda Group's Coltide HSI-LQ-(SG).

[0052] The natural foliated silicate was purchased from BYK GmbH, Germany, model number PURABYK-P 5540.

[0053] EO / PO block polyether was purchased from BASF, Germany (Pluronic PE 6100). Secondary alcohol ethoxylate was purchased from Dow Chemical (ECOSURFT MLF-30). Examples

[0054] Example 1: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A1 and a single-layer detergent sheet A2 that are self-adhesive.

[0055] Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, comprises the following raw materials: 28% polyvinyl alcohol, 30% sodium α-alkenyl sulfonate, 5% sodium isomeric alcohol ether sulfate, 5% alkyl glycoside alkoxy compound, 5% fatty acid methyl ester ethoxy compound, 3% lauric acid, 1% citric acid, 1% solid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 18.9% water.

[0056] Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, comprises the following raw materials: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 10% sodium α-alkenyl sulfonate, 3% sodium fatty acid methyl ester ethoxylated sulfonate, 3% sodium isooctyl sulfate, 6% secondary alcohol ethoxylate, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% fragrance, and 23% water.

[0057] Testing revealed that the optimal thickness for single-layer detergent sheet A is 0.3-3.5 mm, and for single-layer detergent sheet B, it is 0.3-3.0 mm. The amount of slurry can be adjusted according to actual conditions to obtain single-layer detergent sheets of the corresponding thickness.

[0058] This embodiment also provides a method for preparing a double-layer low-foaming detergent sheet, including the following steps: Step 1: Prepare slurry A1, including the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen evenly, add sodium α-alkenyl sulfonate and sodium isomeric alcohol ether sulfate, stir and dissolve evenly, and stop heating.

[0059] Step 1b: Add alkyl glycoside alkoxy compound, fatty acid methyl ester ethoxy compound, lauric acid, citric acid, glycerol, fragrance, and dye in sequence, stir and dissolve evenly to obtain slurry A1.

[0060] Step 2: Prepare slurry A2, including the following steps: Step 2a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium ethoxylated fatty acid methyl ester sulfonate, sodium methyl fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, and sodium isooctyl sulfate. Stir until dissolved and uniform, and then stop heating.

[0061] Step 2b: Add EO / PO block polyether, secondary alcohol ethoxylate, stearic acid, citric acid, propylene glycol, and fragrance in sequence, stir and dissolve evenly to obtain slurry A2.

[0062] Step 3: Dry the slurry A1 and form tablets. During the drying and tableting process, solid protease is added in the form of spray to obtain a single-layer washing tablet A1.

[0063] Step 4: When drying slurry A2, attach single-layer detergent sheet A1 to the surface of the semi-formed single-layer detergent sheet A2 and continue drying to obtain double-layer low-foam detergent sheet.

[0064] The semi-dry self-adhesive process allows the layers of a single-layer detergent sheet in a double-layer low-foam detergent sheet to self-adhere between the smooth surface of one layer and the rough surface of the other.

[0065] Refer to Figure 1 for a cross-sectional microscope image of the double-layer low-foaming washing tablet.

[0066] Example 2: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A and a single-layer detergent sheet B that are self-adhesive.

[0067] Single-layer detergent sheet A is prepared from slurry A, which, by weight percentage, includes the following raw materials: 28% polyvinyl alcohol, 20% sodium lauroyl glutamate, 5% sodium isomeric alcohol ether sulfate, 2% alkyl glycoside alkoxy compound, 3% secondary alcohol ethoxy compound, 2% lauric acid, 1% citric acid, 2% butanediol, 1% fragrance, and 36% water.

[0068] Single-layer detergent sheet B is prepared from slurry B, which, by weight percentage, includes the following raw materials: 10% sodium alginate, 2% carboxymethyl cellulose, 25% sodium alkyl sulfate, 8% hydrolyzed wheat protein / silicone copolymer, 3% sodium hydroxide, 2% octanediol, 1% liquid protease, 1% fragrance, and 48% water.

[0069] In this embodiment, sodium dodecyl sulfate is selected as the alkyl sulfate.

[0070] This embodiment also provides a method for preparing a double-layer low-foaming detergent sheet, including the following steps: Step 1: Prepare slurry A, including the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 75°C. After the polyvinyl alcohol has swollen evenly, add sodium lauroyl glutamate and sodium isomeric alcohol ether sulfate, stir and dissolve evenly, and stop heating.

[0071] Step 1b: Add alkyl glycoside alkoxy compound, secondary alcohol ethoxy compound, lauric acid, citric acid, butanediol, and fragrance in sequence, stir and dissolve evenly to obtain slurry A.

[0072] Step 2: Prepare slurry B, including the following steps: Step 2a: Mix water, sodium alginate and carboxymethyl cellulose, and let stand at 20°C to fully swell until a homogeneous viscous liquid is formed.

[0073] Step 2b: Heat to 38°C, add sodium alkyl sulfate and octanediol, and stir until dissolved.

[0074] Step 2c: Continue to add hydrolyzed wheat protein / silicone copolymer, sodium hydroxide, liquid protease, and flavoring, stir and dissolve evenly to obtain slurry B.

[0075] Step 3: Dry the slurry A, shape it into sheets, and obtain a single-layer washing sheet A.

[0076] Step 4: When drying slurry B, attach single-layer detergent sheet A to the surface of the semi-formed single-layer detergent sheet B, and continue drying to obtain double-layer low-foam detergent sheet.

[0077] Example 3 A three-layer low-foam detergent sheet, which is composed of a single-layer detergent sheet A1, a single-layer detergent sheet B and a single-layer detergent sheet A2 that are self-adhesive.

[0078] First layer: Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, includes the following raw materials: 20% polyvinyl alcohol, 16% sodium fatty acid methyl ester sulfonate, 7% sodium α-alkenyl sulfonate, 7% sodium lauroyl glutamate, 5% sodium fatty acid methyl ester ethoxylated sulfonate, 4% sodium isomeric alcohol ether sulfate, 1% sodium isooctyl sulfate, 10% alkyl glycoside alkoxy compound, 5% EO / PO block polyether, 3% secondary alcohol ethoxy compound, 5% oleic acid, 1% gluconic acid, 2% hexanediol, 1% fragrance, and 13% water.

[0079] The second layer: Single-layer detergent sheet B is prepared from slurry B, which, by weight percentage, includes the following raw materials: 4% sodium alginate, 4% carboxymethyl cellulose, 15% modified oil ethoxylated compound sodium sulfonate, 13% α-alkenyl sulfonate, 5% natural foliated silicate, 5% sodium carbonate, 2% glycerol, 1% fragrance, 0.1% dye, 1% solid protease, and 49.9% water.

[0080] The third layer: Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, includes the following raw materials: 18% polyvinyl alcohol, 23% sodium lauroyl glutamate, 5% sodium fatty acid methyl ester sulfonate, 3.5% sodium isooctyl sulfate, 2% secondary alcohol ethoxylate, 2% alkyl glycoside alkoxylate, 1% EO / PO block polyether, 1% fatty acid methyl ester ethoxylate, 3% palmitic acid, 1% citric acid, 1% liquid protease, 2% propylene glycol, 1% fragrance, and 36.5% water.

[0081] This embodiment also provides a method for preparing a three-layer low-foaming detergent sheet, including the following steps: Step 1: Prepare slurry A1, including the following steps: Step 1a: Mix water and polyvinyl alcohol and stir and heat to 85°C. After the polyvinyl alcohol has swollen evenly, add sodium fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, sodium lauroyl glutamate, sodium fatty acid methyl ester ethoxylated sulfonate, sodium isomeric alcohol ether sulfate, and sodium isooctyl sulfate. Stir and dissolve evenly, and stop heating.

[0082] Step 1b: Add alkyl glycoside alkoxy compound, EO / PO block polyether, secondary alcohol ethoxy compound, oleic acid, gluconic acid, hexanediol and fragrance in sequence, stir and dissolve evenly to obtain slurry A1.

[0083] Step 2: Prepare slurry B, including the following steps: Step 2a: Mix water, sodium alginate and carboxymethyl cellulose, and let stand at 30°C to fully swell until a homogeneous viscous liquid is formed.

[0084] Step 2b: Heat to 45°C, add modified oil ethoxylated compound sodium sulfonate, α-alkenyl sulfonate, and glycerol, and stir until dissolved and homogeneous.

[0085] Step 2c: Continue to add natural foliated silicate, sodium carbonate, fragrance, and dye, stir and dissolve evenly to obtain slurry B.

[0086] Step 3: Prepare slurry A2, including the following steps: Step 3a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium fatty acid methyl ester sulfonate and sodium isooctyl sulfate, stir and dissolve evenly, and then stop heating.

[0087] Step 3b: Add EO / PO block polyether, fatty acid methyl ester ethoxylate compound, secondary alcohol ethoxylate compound, alkyl glycoside alkoxylate compound, palmitic acid, citric acid, propylene glycol, and fragrance in sequence, and stir until dissolved and homogeneous.

[0088] Step 3c: Cool down to 60℃, add liquid protease and stir until homogeneous to obtain slurry A2.

[0089] Step 4: Dry the slurry A1, shape it into sheets, and obtain a single-layer washing sheet A1.

[0090] Step 5: Dry the slurry B to form a sheet.

[0091] Solid protease is added by spraying during the drying and tableting process.

[0092] After spraying solid protease and drying slurry B to semi-dry, attach single-layer detergent sheet A1 to the surface of the semi-formed single-layer detergent sheet B, and continue drying to obtain self-adhesive single-layer detergent sheet A1 and single-layer detergent sheet B.

[0093] Self-adhesive single-layer detergent sheet A1 and single-layer detergent sheet B are defined as semi-finished products at this time.

[0094] Step 6: When drying slurry A2, attach the semi-finished product obtained in step 5 to the surface of the semi-formed single-layer detergent sheet A2, and continue drying to obtain a three-layer low-foam detergent sheet.

[0095] The surface of the single-layer detergent sheet B in the semi-finished product is in contact with the surface of the semi-formed single-layer detergent sheet A2.

[0096] A cross-sectional microscope image of the three-layer low-foaming detergent tablet is shown in Figure 2, revealing obvious pores. An actual image of the three-layer low-foaming detergent tablet is shown in Figure 3.

[0097] Example 4 A three-layer low-foam detergent sheet, which is composed of a single-layer detergent sheet A1, a single-layer detergent sheet B and a single-layer detergent sheet A2 that are self-adhesive.

[0098] The difference from Example 3 lies in the content of some raw materials in the second layer slurry B. Specifically, slurry B, by weight percentage, includes the following raw materials: 10% sodium alginate, 1% carboxymethyl cellulose, 15% modified oil ethoxylated compound sodium sulfonate, 13% α-alkenyl sulfonate, 5% natural foliated silicate, 5% sodium carbonate, 2% glycerol, 1% fragrance, 0.1% dye, 1% solid protease, and 46.9% water.

[0099] Example 5 A three-layer low-foam detergent sheet, which is composed of a single-layer detergent sheet A1, a single-layer detergent sheet A3 and a single-layer detergent sheet A2 that are self-adhesive.

[0100] The difference from Example 3 is that the second layer is a single-layer washing sheet A3.

[0101] Single-layer detergent sheet A3 is prepared from slurry A3, which, by weight percentage, comprises the following raw materials: 15% polyvinyl alcohol, 13% sodium lauroyl glutamate, 5% sodium α-alkenyl sulfonate, 2.5% sodium isomeric alcohol ether sulfate, 2% fatty acid methyl ester ethoxylate, 1% alkyl glycoside alkoxylate, 1% EO / PO block polyether, 1.5% secondary alcohol ethoxylate, 3% lauric acid, 1% citric acid, 1% solid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 50.9% water.

[0102] Furthermore, in the preparation method of the three-layer low-foaming detergent sheet, step 2 is changed to preparing slurry A3, which includes the following steps: Step 2a: Mix water and polyvinyl alcohol and stir and heat to 85°C. After the polyvinyl alcohol swells evenly, add sodium α-alkenyl sulfonate, sodium lauroyl glutamate, and sodium isomeric alcohol ether sulfate, stir and dissolve evenly, and stop heating.

[0103] Step 2b: Add alkyl glycoside alkoxy compound, fatty acid methyl ester ethoxy compound, EO / PO block polyether, secondary alcohol ethoxy compound, lauric acid, citric acid, glycerol, fragrance, and dye in sequence, and stir until dissolved to obtain slurry A3.

[0104] Example 6: A four-layer low-foam detergent sheet, composed of single-layer detergent sheet A1, single-layer detergent sheet B1, single-layer detergent sheet B2, and single-layer detergent sheet A2 self-adhesive. The first and second layers are the same as in Example 3, and the fourth layer is basically the same as the third layer in Example 3.

[0105] The fourth layer differs from the third layer in Example 3 in that 0.1% dye is added to the fourth layer, and the amount of water is reduced by 0.1% accordingly. This is only to facilitate the identification of layers and does not affect the actual efficacy.

[0106] The slurry for the third single-layer detergent sheet B2 is composed of the following raw materials: 14% sodium alginate, 1% carboxymethyl cellulose, 15% sodium fatty acid methyl ester sulfonate, 5% sodium α-alkenyl sulfonate, 5% natural foliated silicate, 5% sodium carbonate, 2% glycerin, 1% fragrance, and 52% water.

[0107] A method for preparing a four-layer low-foaming detergent sheet includes the following steps: Step 1: Prepare slurry A1, including the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 85°C. After the polyvinyl alcohol has swollen and become uniform, add sodium fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, sodium lauroyl glutamate, sodium fatty acid methyl ester ethoxylated sulfonate, sodium isomeric alcohol ether sulfate, and sodium isooctyl sulfate. Stir and dissolve evenly, then stop heating.

[0108] Step 1b: Add alkyl glycoside alkoxy compound, EO / PO block polyether, secondary alcohol ethoxy compound, oleic acid, gluconic acid, hexanediol and fragrance in sequence, stir and dissolve evenly to obtain slurry A1.

[0109] Step 2: Prepare slurry B1, including the following steps: Step 2a: Mix water, sodium alginate and carboxymethyl cellulose, and let stand at 30°C to fully swell until a homogeneous viscous liquid is formed.

[0110] Step 2b: Heat to 45°C, add modified oil ethoxylated compound sodium sulfonate, α-alkenyl sulfonate, and glycerol, and stir until dissolved and homogeneous.

[0111] Step 2c: Continue to add natural foliated silicate, sodium carbonate, fragrance, and dye, stir and dissolve evenly to obtain slurry B1.

[0112] Step 3: Prepare slurry B2, including the following steps: Step 3a: Mix water, sodium alginate and carboxymethyl cellulose, and let stand at 30°C to fully swell until a homogeneous viscous liquid is formed.

[0113] Step 3b: Heat to 45℃, add sodium fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, and glycerol, and stir until dissolved and homogeneous.

[0114] Step 3c: Continue to add natural foliated silicate, sodium carbonate, fragrance, and dye, stir and dissolve evenly to obtain slurry B2.

[0115] Step 4: Prepare slurry A2, including the following steps: Step 4a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium fatty acid methyl ester sulfonate and sodium isooctyl sulfate, stir and dissolve evenly, and then stop heating.

[0116] Step 4b: Add EO / PO block polyether, fatty acid methyl ester ethoxylate compound, secondary alcohol ethoxylate compound, alkyl glycoside alkoxylate compound, palmitic acid, citric acid, propylene glycol, and fragrance in sequence, and stir until dissolved and homogeneous.

[0117] Step 4c: Cool down to 60℃, add liquid protease and stir until homogeneous to obtain slurry A2.

[0118] Step 5: Dry the slurry A1, shape it into sheets, and obtain a single-layer washing sheet A1.

[0119] Step 6: Dry the slurry B1 to form a sheet.

[0120] Solid protease is added by spraying during the drying and tableting process.

[0121] After spraying solid protease and drying slurry B to semi-dry, attach single-layer detergent sheet A1 to the surface of semi-formed single-layer detergent sheet B1, and continue drying to obtain self-adhesive single-layer detergent sheet A1 and single-layer detergent sheet B1.

[0122] The self-adhesive single-layer detergent sheet A1 and single-layer detergent sheet B1 are defined as the first semi-finished product at this time.

[0123] Step 7: When drying slurry B2, attach the first semi-finished product obtained in step 6 to the surface of the semi-formed single-layer washing sheet B2, and continue to form it into a sheet to obtain the second semi-finished product.

[0124] The surface of the single-layer washing sheet B1 is in contact with the surface of the semi-formed single-layer washing sheet B2.

[0125] Step 8: When drying slurry A2, attach the second semi-finished product obtained in step 7 to the surface of the semi-formed single-layer detergent sheet A2, and continue drying to obtain a four-layer low-foam detergent sheet.

[0126] Single-layer detergent sheet B2 is in contact with the surface of semi-formed single-layer detergent sheet A2.

[0127] A cross-sectional microscope image of the four-layer low-foam washing sheet is shown in Figure 4.

[0128] Comparative Example 1: A double-layer laundry sheet comprising two single-layer laundry sheets bonded together by a liquid protease and an adhesive.

[0129] Specifically, the single-layer laundry detergent sheet contains the following raw materials: 35% polyvinyl alcohol, 19% sodium dodecylbenzene sulfonate, 20% sodium α-olefin sulfonate, 6% fatty alcohol polyoxyethylene ether, 2% sodium citrate, 1.3% glycerol, 1% liquid protease, 0.1% pigment, and 15.6% deionized water.

[0130] The preparation method of single-layer laundry detergent sheets includes the following steps: adding polyvinyl alcohol and deionized water to a mixing pot, stirring and pre-dissolving for 30 minutes, controlling the temperature at 60℃, until completely dissolved.

[0131] Add sodium dodecylbenzenesulfonate, sodium α-olefin sulfonate, fatty alcohol polyoxyethylene ether, glycerin, sodium citrate and pigment to the mixing pot. Control the temperature of the mixing pot at 80℃ and stir for 50 minutes to obtain a uniform slurry.

[0132] The slurry is transferred to a drying drum at 100°C and dried to produce a single-layer laundry sheet.

[0133] The preparation method of double-layer laundry detergent sheets includes the following steps: Take two single-layer laundry detergent sheets and apply liquid protease to the surface of each single-layer laundry detergent sheet.

[0134] The single-layer laundry sheets coated with liquid protease are bonded and extruded together using an adhesive machine, and then produced into double-layer laundry sheets through hot shearing, stamping, and packaging.

[0135] Comparative Example 2: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A1 and a single-layer detergent sheet A2 that are self-adhesive.

[0136] The difference from Example 1 is that the raw materials of slurry A1 and slurry A2 are partially different, as follows: Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, includes the following raw materials: 28% polyvinyl alcohol, 35% sodium isomeric alcohol ether sulfate, 5% alkyl glycoside alkoxy compound, 5% fatty acid methyl ester ethoxy compound, 3% lauric acid, 1% citric acid, 1% liquid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 18.9% water.

[0137] Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, includes the following raw materials: 25% polyvinyl alcohol, 30% sodium fatty acid methyl ester ethoxylated sulfonate, 3% sodium isooctanol sulfate, 6% secondary alcohol ethoxylated compound, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% fragrance, and 23% water.

[0138] A method for preparing a double-layer low-foaming detergent sheet differs from Example 1 in that steps 1 and 2 are different, while the rest are the same.

[0139] Specifically, step 1 includes the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen evenly, add sodium isomeric alcohol ether sulfate, stir and dissolve evenly, and then stop heating.

[0140] Step 1b: Add alkyl glycoside alkoxy compound, fatty acid methyl ester ethoxy compound, lauric acid, citric acid, glycerol, fragrance, liquid protease, and dye in sequence, stir and dissolve evenly to obtain slurry A1.

[0141] Step 2 includes the following steps: Step 2a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium ethoxylated fatty acid methyl ester sulfonate and sodium isooctyl sulfate, stir and dissolve evenly, and then stop heating.

[0142] Step 2b: Add EO / PO block polyether, secondary alcohol ethoxylate, stearic acid, citric acid, propylene glycol, and fragrance in sequence, stir and dissolve evenly to obtain slurry A2.

[0143] Because neither of the single-layer detergent sheets A1 nor A2 in this comparative example used a high-foaming surfactant, the single-layer molding was poor, resulting in backflow of the slurry during sheet production and the formation of waterfall marks. Furthermore, the single-layer detergent sheets were very thin and easily floated in water, leading to slow dissolution.

[0144] A physical image of the single-layer detergent sheet A1 is shown in Figure 5.

[0145] Comparative Example 3: A double-layer low-foaming detergent sheet, which differs from Example 1 in that both single-layer detergent sheets A1 and A2 use sodium dodecylbenzenesulfonate in an equal amount to replace sodium α-olefin sulfonate.

[0146] Comparative Example 4: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A1 and a single-layer detergent sheet A2 that are self-adhesive.

[0147] The difference from Example 1 is that the raw materials of slurry A1 and slurry A2 are partially different, as follows: Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, includes the following raw materials: 28% polyvinyl alcohol, 35% sodium α-alkenyl sulfonate, 5% alkyl glycoside alkoxy compound, 5% fatty acid methyl ester ethoxy compound, 3% lauric acid, 1% citric acid, 1% liquid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 18.9% water.

[0148] Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, comprises the following raw materials: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 13% sodium α-alkenyl sulfonate, 3% sodium isooctyl sulfate, 6% secondary alcohol ethoxylate, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% fragrance, and 23% water.

[0149] A method for preparing a double-layer low-foaming detergent sheet differs from Example 1 in that steps 1 and 2 are different, while the rest are the same.

[0150] Specifically, step 1 includes the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium α-alkenyl sulfonate, stir and dissolve evenly, and then stop heating.

[0151] Step 1b: Add alkyl glycoside alkoxy compound, fatty acid methyl ester ethoxy compound, lauric acid, citric acid, glycerol, fragrance, liquid protease, and dye in sequence, stir and dissolve evenly to obtain slurry A1.

[0152] Step 2 includes the following steps: Step 2a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, and sodium isooctyl sulfate. Stir until dissolved and uniform, then stop heating.

[0153] Step 2b: Add EO / PO block polyether, secondary alcohol ethoxylate, stearic acid, citric acid, propylene glycol, and fragrance in sequence, stir and dissolve evenly to obtain slurry A2.

[0154] Comparative Example 5: A double-layer low-foaming detergent sheet, which differs from Example 1 in that the raw materials of slurry A1 and slurry A2 are partially different, as follows: Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, includes the following raw materials: 28% polyvinyl alcohol, 30% sodium α-alkenyl sulfonate, 5% sodium isomeric alcohol ether sulfate, 3% lauric acid, 1% citric acid, 1% solid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 28.9% water.

[0155] Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, includes the following raw materials: 25% polyvinyl alcohol, 17% sodium methyl ester sulfonate of fatty acids, 10% sodium α-alkenyl sulfonate, 3% sodium ethoxylated methyl ester sulfonate of fatty acids, 3% sodium isooctyl sulfate, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% fragrance, and 36% water.

[0156] A method for preparing a double-layer low-foaming detergent sheet differs from Example 1 in that steps 1 and 2 are different, while the rest are the same.

[0157] Specifically, step 1 includes the following steps: mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium α-alkenyl sulfonate, sodium isomeric alcohol ether sulfate, lauric acid, citric acid, glycerin, fragrance, and dye. Stir and dissolve evenly to obtain slurry A1.

[0158] Step 2: Prepare slurry A2, including the following steps: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium ethoxylated fatty acid methyl ester sulfonate, sodium methyl fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, sodium isooctyl sulfate, stearic acid, citric acid, propylene glycol, and fragrance. Stir and dissolve evenly to obtain slurry A2.

[0159] Comparative Example 6: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A1 and a single-layer detergent sheet A2 that are self-adhesive.

[0160] The difference from Example 1 is that the raw materials of slurry A1 and slurry A2 are partially different, as follows: Single-layer detergent sheet A1 is prepared from slurry A1, which, by weight percentage, includes the following raw materials: 28% polyvinyl alcohol, 30% sodium α-alkenyl sulfonate, 5% sodium isomeric alcohol ether sulfate, 5% alkyl glycoside, 5% fatty alcohol polyoxyethylene ether, 3% lauric acid, 1% citric acid, 1% liquid protease, 2% glycerol, 1% fragrance, 0.1% dye, and 18.9% water.

[0161] Single-layer detergent sheet A2 is prepared from slurry A2, which, by weight percentage, comprises the following raw materials: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 10% sodium α-alkenyl sulfonate, 3% sodium fatty acid methyl ester ethoxylated sulfonate, 3% sodium isooctanol sulfate, 13% coconut oil fatty acid diethanolamide, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% fragrance, and 23% water.

[0162] A method for preparing a double-layer low-foaming detergent sheet differs from Example 1 in that steps 1 and 2 are different, while the rest are the same.

[0163] Specifically, step 1 includes the following steps: Step 1a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium α-alkenyl sulfonate and sodium isomeric alcohol ether sulfate, stir and dissolve evenly, and then stop heating.

[0164] Step 1b: Add alkyl glycoside, fatty alcohol polyoxyethylene ether, lauric acid, citric acid, glycerol, fragrance, liquid protease, and dye in sequence, stir and dissolve evenly to obtain slurry A1.

[0165] Step 2: Prepare slurry A2, including the following steps: Step 2a: Mix water and polyvinyl alcohol and heat to 80°C. After the polyvinyl alcohol has swollen and become uniform, add sodium ethoxylated fatty acid methyl ester sulfonate, sodium methyl fatty acid methyl ester sulfonate, sodium α-alkenyl sulfonate, and sodium isooctyl sulfate. Stir until dissolved and uniform, and then stop heating.

[0166] Step 2b: Add coconut oil fatty acid diethanolamide, stearic acid, citric acid, propylene glycol and flavoring in sequence, stir and dissolve evenly to obtain slurry A2.

[0167] Comparative Example 7: A double-layer low-foaming detergent sheet, which is composed of a single-layer detergent sheet A and a single-layer detergent sheet B that are self-adhesive.

[0168] The difference from Example 2 is that the composition of the single-layer detergent sheet B is adjusted: The single-layer detergent sheet B is prepared from slurry B, which, by weight percentage, includes the following raw materials: 12% carboxymethyl cellulose, 25% sodium alkyl sulfate, 8% hydrolyzed wheat protein / silicone copolymer, 3% sodium hydroxide, 2% octanediol, 1% liquid protease, 1% fragrance, and 48% water.

[0169] A method for preparing a double-layer low-foaming detergent sheet differs from Example 2 in that step 2 is different.

[0170] Specifically, step 2 includes the following steps: Step 2a: Mix water and carboxymethyl cellulose, and let stand at 20°C to fully swell until a homogeneous viscous liquid is formed.

[0171] Step 2b: Heat to 38°C, add sodium alkyl sulfate and octanediol, and stir until dissolved.

[0172] Step 2c: Continue to add hydrolyzed wheat protein / silicone copolymer, sodium hydroxide, liquid protease, and flavoring, stir and dissolve evenly to obtain slurry B.

[0173] When drying slurry B separately to prepare single-layer washing sheets B, it was found that it could not be formed. See Figure 6 for the actual situation.

[0174] Therefore, this comparative example could not obtain the corresponding double-layer low-foam detergent sheet, and subsequent testing could not be performed.

[0175] Comparative Example 8 A double-layer low-foaming washing sheet is composed of a single-layer washing sheet A and a single-layer washing sheet B self-bonded together.

[0176] The difference from Example 2 is that the composition of the single-layer washing sheet B is adjusted: the single-layer washing sheet B is prepared from slurry B, and slurry B includes the following raw materials by weight percentage: 20% sodium alginate, 25% sodium alkyl sulfate, 8% hydrolyzed wheat protein / silicone copolymer, 3% sodium hydroxide, 2% octanediol, 1% liquid protease, 1% essence, and 40% water.

[0177] A preparation method of a double-layer low-foaming washing sheet, the difference from Example 2 is that: part of Step 2 is different, and the rest is the same.

[0178] Specifically, Step 2 includes the following steps: Step 2a: Mix water and sodium alginate, and let it stand at 20°C to fully swell into a homogeneous viscous liquid.

[0179] Step 2b: Raise the temperature to 38°C, add sodium alkyl sulfate and octanediol, and stir to dissolve evenly.

[0180] Step 2c: Continuously add hydrolyzed wheat protein / silicone copolymer, sodium hydroxide, liquid protease, and essence, and stir to dissolve evenly to obtain slurry B.

[0181] Performance detection test Test 1: Detergency test According to GB / T 13174-2021 "Determination of Detergency and Recycling Washing Performance of Detergents for Clothing", the washing water is 250 mg / kg CaCl2 hard water, and the test cloth pieces are national standard carbon black JB-01 soiled cloth, national standard protein JB-02 soiled cloth, and national standard sebum JB-03 soiled cloth.

[0182] Taking 0.2% standard laundry detergent as a control, cut the sample into a small piece with an area of 2 cm * 2 cm (2 cm * 2 cm), and prepare a sample solution with 1 L of hard water to obtain the detergency ratio Pi.

[0183] The detection results are shown in Table 1 respectively.

[0184] Among them, when Pi ≥ 1.0 is qualified, and Pi < 1.0 is unqualified. <000037​​​​​​

[0186] The phenomenon can be categorized into complete tearing (layers can be separated completely without damage), incomplete tearing (layers can be separated completely but are damaged), and inability to tear.

[0187] Table 2 The test results of the double-layer detergent sheets in Comparative Examples 1-6 and Comparative Example 8 are shown in Figures 7-8.

[0188] Test 3: Dissolution time. According to QB / T5779-2023 "Laundry Detergent Sheets", 700mL of hard water (250mg / kg calcium chloride) was placed in a 1L beaker and placed in a water bath environment at (23±2)℃. The stirring speed of the magnetic stirrer was adjusted. Double / multi-layer laundry detergent sheets were cut into 3cm*3cm square pieces, placed 10cm parallel to the water surface, and dropped vertically into the water.

[0189] The timer starts when the laundry detergent sheet touches the water surface and stops when the sample is completely dispersed in the water, thus obtaining the dissolution time.

[0190] Repeat 3 times in parallel.

[0191] Record the results in Table 3.

[0192] Table 3 Test 4: Foam Height. According to GB / T 13173-2021 "Test Methods for Surfactants and Detergents", double / multi-layer laundry sheets were prepared into a 1% solution using 250 mg / L hard water. The foam height was recorded at 0 and 5 minutes at 40°C using a Roche foam meter.

[0193] Record the results in Table 4.

[0194] For details of the test, please refer to Figure 9-12. The mean value before the test corresponds to the starting value at 0 minutes, and the mean value after the test corresponds to the starting value at 5 minutes.

[0195] Table 4 According to the test results, the laundry sheets of Examples 1-6 have good stain removal effect, dissolve quickly, have strong interlayer bonding, and produce low foam during washing. Their performance in all aspects is significantly better than that of Comparative Examples 1-6 and 8.

[0196] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A multi-layer low-foaming detergent sheet, characterized in that, It consists of two or more single-layer washing sheets bonded together by self-adhesion; Among them, at least one single-layer washing sheet is a single-layer washing sheet A; Single-layer detergent sheet A is prepared from slurry A, which includes the following raw materials by weight percentage: 10-30% film-forming agent A, 20-50% anionic surfactant A, 5-20% nonionic surfactant, 2-10% acidifier, 0.5-3% chelating agent, 0-5% enzyme preparation A, 1-5% auxiliary agent A, 0.5-5% fragrance A, water; Film-forming agent A includes polyvinyl alcohol; Anionic surfactant A includes high-foaming surfactants and low-foaming surfactants; the weight ratio of high-foaming anionic surfactants to low-foaming anionic surfactants is (3-10):

1. High-foaming anionic surfactants include at least one of sodium α-alkenyl sulfonate, sodium fatty acid methyl ester sulfonate, and sodium lauroyl glutamate; Low-foaming anionic surfactants include at least one of sodium isomeric alcohol ether sulfate, sodium fatty acid methyl ester ethoxylated sulfonate, and sodium isooctyl sulfate; Nonionic surfactants include at least two of the following: EO / PO block polyethers, fatty acid methyl ester ethoxy compounds, secondary alcohol ethoxy compounds, and alkyl glycoside alkoxy compounds.

2. The multi-layer low-foaming detergent sheet according to claim 1, characterized in that: The weight ratio of the anionic surfactant A to the nonionic surfactant is (2-10):

1.

3. The multi-layer low-foaming detergent sheet according to claim 1, characterized in that: The single-layer detergent sheet also includes a single-layer detergent sheet B, which is prepared from slurry B and comprises the following raw materials by weight percentage: 3-20% film-forming agent B, 10-30% anionic surfactant B, 5-10% softener, 2-10% alkalizing agent, 0-5% enzyme preparation B, 1-5% auxiliary agent B, 0.5-5% fragrance B, and water; Film-forming agent B includes at least sodium alginate and carboxymethyl cellulose, with a weight ratio of sodium alginate to carboxymethyl cellulose of (1-15):1; Anionic surfactant B includes at least one of sodium α-olefin sulfonate, sodium alkyl sulfate, modified oil ethoxylate sulfonate, and sodium fatty acid methyl ester sulfonate.

4. The multi-layer low-foaming detergent sheet according to claim 3, characterized in that: The acidifier includes C12-C18 fatty acids.

5. The multi-layer low-foaming detergent sheet according to claim 3, characterized in that: The alkalizing agent includes at least one of sodium hydroxide / potassium, sodium carbonate / potassium, and sodium citrate / potassium.

6. The multi-layer low-foaming detergent sheet according to claim 1, characterized in that: The single-layer washing sheet A is located on the outermost layer.

7. The multi-layer low-foaming detergent sheet according to claim 3, characterized in that: The single-layer detergent sheet A is located on the outermost layer, and the single-layer detergent sheet B is located in the middle.

8. The multi-layer low-foaming detergent sheet according to claim 3, characterized in that: The thickness of the single-layer detergent sheet A is 0.3-3.5 mm, and the thickness of the single-layer detergent sheet B is 0.3-3.0 mm.

9. The multi-layer low-foaming detergent sheet according to claim 1, characterized in that: One side of the single-layer detergent sheet is smooth, and the other side is rough. In the multi-layer low-foam detergent sheet, the layers of the single-layer detergent sheet are self-adhesive between the smooth surface of one layer and the rough surface of another layer.

10. A method for preparing a multilayer low-foaming detergent sheet according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Prepare slurry A, including the following steps: Step 1a: Mix and stir water and film-forming agent A at 75-85℃. After the film-forming agent has swollen evenly, add anionic surfactant A and stir until it is evenly dissolved. Step 1b: Continue adding the remaining raw materials of slurry A and stir until uniform to obtain slurry A; Step 2: If it contains a single-layer washing sheet B, then prepare slurry B, including the following steps: Step 2a: Mix water and film-forming agent B, and allow it to swell fully at 20-30°C until it becomes a homogeneous viscous liquid; Step 2b: Under conditions of 38-45℃, add anionic surfactant B and auxiliary agent B and stir until dissolved and homogeneous; Step 2c: Continue adding the remaining raw materials of slurry B to obtain slurry B; If single-layer washing sheet B is not included, this step is omitted, and step 3 is performed after step 1; Step 3: During the drying and forming stage of the slurry for preparing any single-layer detergent sheet, attach another single-layer or multi-layer detergent sheet that has already completed the drying and forming stage, and continue drying until multi-layer low-foam detergent sheets are obtained.

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