Multi-layer low-foam washing sheet and preparation method thereof

Abstract

The invention relates to a multi-layer low-foam washing sheet and a preparation method thereof. A multi-layer low-foam washing sheet is composed of double-layer or multi-layer single-layer washing sheets in a self-bonding mode. Wherein at least one layer of single-layer washing sheet is a single-layer washing sheet A; the single-layer washing sheet A is prepared from slurry A, and the slurry A comprises a film-forming agent A, an anionic surfactant A, a nonionic surfactant, an acidifying agent, a chelating agent, an enzyme preparation A, an auxiliary A, essence A and water. The multi-layer low-foam washing sheet has the advantages of being high in cleaning capacity, low in foam, short in dissolving time and the like.

Description

Technical Field

[0001] The present application relates to the field of washing tablets, and more specifically, to a multi-layer low-foaming washing tablet and a preparation method thereof. Background Art

[0002] Currently, since laundry beads and washing tablets are used in a metered manner, they are deeply loved by consumers due to their convenience. The maximum weight of a single laundry bead can reach 20 g, and the average weight of a single washing tablet is 4 g. Therefore, in actual use, compared with laundry beads, due to the limited surfactant carried by a single sheet of the washing tablet, its cleaning ability is limited. And the most direct way to solve this problem nowadays is to use several more washing tablets.

[0003] Although using multiple washing tablets simultaneously or using a single multi-layer washing tablet can bring beneficial effects to the cleaning power, the total active matter content increases multiple times, resulting in a multiple increase in the amount of foam. When in use, the foam easily overflows from the washing machine, increasing the number of rinsing times and water consumption during use.

[0004] When preparing the tablet slurry, certain foaming and foaming properties are required, while low-foaming and easy-rinsing characteristics are required during the use of the finished product. This characteristic makes it impossible to solve the problem of excessive foam caused by high total active matter by directly adding defoamers or using low-foaming surfactants.

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

[0006] To solve the above problems, the present application provides a multi-layer low-foaming washing tablet and a preparation method thereof. The multi-layer low-foaming washing tablet has the characteristics of high cleaning power, low foam, and fast dissolution time.

[0007] In a first aspect, the present application provides a multi-layer low-foaming washing tablet, adopting the following technical solution: A multi-layer low-foaming washing tablet is composed of two or more single-layer washing tablets through self-bonding; Among them, at least one single-layer washing tablet is single-layer washing tablet A; Single-layer washing tablet A is prepared from slurry A. 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% non-ionic surfactant, 2-10% acidifying agent, 0.5-3% chelating agent, 0-5% enzyme preparation A, 1-5% auxiliary agent A, 0.5-5% essence A, water; Film-forming agent A includes polyvinyl alcohol; The anionic surfactant A includes high-foaming surfactants and low-foaming surfactants; the weight ratio of the high-foaming anionic surfactant to the low-foaming anionic surfactant is (3 - 10):1; The high-foaming anionic surfactant includes at least one of sodium α-olefin sulfonate, sodium fatty acid methyl ester sulfonate, and sodium lauroyl glutamate; The low-foaming anionic surfactant includes at least one of isomeric alcohol ether sulfate, fatty acid methyl ester ethoxylated sulfonate, and sodium isooctyl sulfate; The non-ionic surfactant includes at least two of EO / PO block polyethers, fatty acid methyl ester ethoxylates, secondary alcohol ethoxylates, and alkyl glycoside alkoxylates.

[0008] The intermolecular forces between the hydrophilic and lipophilic groups in alkyl glycoside alkoxylates, secondary alcohol ethoxylates, and fatty acid methyl ester ethoxylates are weak and it is not easy to form a large amount of foam. Fatty acid methyl ester ethoxylated sulfonates and sodium modified oil ethoxylated compound sulfonates have both anionic and non-ionic characteristics and belong to anionic-non-ionic amphoteric surfactants. Due to the introduction of sulfonic acid groups, their molecular polarity is enhanced, making it easier for them to interact with water molecules in the solution, thereby further reducing the generation of foam. In the solution, their molecules can form stable micelle structures, and the intermolecular forces between these micelles are weak and it is not easy to form a large amount of foam.

[0009] The polyoxyethylene group in EO / PO block polyethers is a hydrophilic group and the polyoxypropylene group is a lipophilic group. This structure makes EO / PO block polyethers more likely to form micelles in aqueous solutions and have a relatively large surface tension. At the same time, the hydrophilic and lipophilic groups are arranged in an alternating and mixed manner, with spatial hindrance to form voids between a large number of liquid films, weakening the strength of the liquid film and making the foam film walls formed more likely to break.

[0010] In this application, the high-foaming surfactant is used as the main surfactant and is formulated with specific low-foaming surfactants; through the synergistic effect of the two types of surfactants, on the one hand, during the preparation of the slurry, a certain amount of dense foam can be generated, ensuring the thickness and abundant pores of the multi-layer washing tablets. When the multi-layer washing tablets are used, water molecules can enter the inside of the tablets from the pores, thereby accelerating the dissolution rate; on the other hand, the multi-layer low-foaming washing tablets prepared in this application not only have a low foam amount but also a fast defoaming rate when used, which can reduce the number of rinsing times and water consumption, and is of great significance for energy conservation and emission reduction; and at the same time, it ensures a high detergency effect and has a variety of excellent properties.

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

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

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

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

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

[0016] Preferably, the C3-C18 polyols include at least one of glycerol, propanetriol, butanediol, hexanediol, and octanediol.

[0017] Preferably, the single-layer washing tablet further includes a single-layer washing tablet B, which is prepared from slurry B. According to the weight percentage of slurry B, it includes the following raw materials: 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 B, 0.5-5% essence B, and water; The film-forming agent B includes at least sodium alginate and carboxymethyl cellulose, and the weight ratio of sodium alginate to carboxymethyl cellulose is (1-15):1; The anionic surfactant B includes at least one of α-olefin sulfonate, alkyl sulfate, modified oil ethoxy compound sulfonate, and fatty acid methyl ester sulfonate.

[0018] Preferably, the 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 acidifying agent includes 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 the single-layer washing sheet A contains fatty acids and the single-layer washing sheet B contains an alkalizing agent, when the single-layer washing sheet A and the single-layer washing sheet B are self-bonded, a fatty acid salt "saponification layer" will be slowly formed between the layers at high temperature, further promoting the self-bonding between the layers. When the multi-layer washing sheet is dissolved in water, the fatty acid salt can form a film layer similar to mineral oil on the liquid surface, further reducing the surface tension, thereby inhibiting the generation of foam. At the same time, it can also have an affinity with the liquid molecules inside the foam, causing the foam to break and destroying the stability of the foam.

[0023] Adding fatty acid salt directly to the slurry will affect the foaming property of the slurry. Therefore, forming a fatty acid salt "saponification layer" during the preparation process of the multi-layer washing sheet can avoid the above problems, and at the same time can further reduce the amount of foam during the use of the multi-layer washing sheet.

[0024] Preferably, the softener includes at least one of natural phyllosilicates, hydrolyzed wheat protein / silicone copolymers, and amino silicone oils.

[0025] In this application, the specific categories of enzyme preparation B and auxiliary B are the same as those of enzyme preparation A and auxiliary A respectively. Preferably, the single-layer washing sheet A is located on 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, between the layers of the single-layer washing sheets in the multi-layer low-foam washing sheet, the smooth surface of one layer is self-bonded to the rough surface of another layer.

[0029] Preferably, in the multi-layer low-foam washing sheet, the solid preparations in enzyme preparation A and enzyme preparation B are preferably completely wrapped between the layers, and the liquid preparation and the solid preparation can be simultaneously not added to the same layer of washing sheet.

[0030] In the second aspect, this application provides a preparation method for a multi-layer low-foam washing sheet, adopting the following technical solution: A preparation method for a multi-layer low-foam washing sheet, comprising 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 °C. After the film-forming agent swells evenly, add anionic surfactant A and stir to dissolve evenly; Step 1b: Continuously add the remaining raw materials of slurry A and stir until uniform to obtain slurry A; If slurry A contains enzyme preparation A, when enzyme preparation A contains liquid enzyme preparation, raw materials are added in step 1b, and after cooling to 58 - 63°C, the liquid enzyme preparation is added and mixed evenly to obtain slurry A; when enzyme preparation A contains solid enzyme preparation, it is added in the form of spraying during the drying and tablet-making in step 3. Step 2: If monolayer washing tablet B is included, prepare slurry B, including the following steps: Step 2a: Mix water and film-forming agent B, and fully swell to a homogeneous viscous liquid under the condition of 20 - 30°C. Step 2b: At 38 - 45°C, add anionic surfactant B and auxiliary agent B and stir to dissolve 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, the liquid enzyme preparation is added in step 2b and mixed evenly to obtain slurry B; when enzyme preparation B contains solid enzyme preparation, it is added in the form of spraying during the drying and tablet-making in step 3. If monolayer washing tablet B is not included, omit this step, and step 3 is carried out after step 1 ends. Step 3: When the slurry for preparing any monolayer washing tablet is in the drying and forming stage, attach another monolayer or multilayer washing tablet that has completed the drying and forming stage, and continue drying until a multilayer low-foam washing tablet is obtained.

[0031] When the same type of monolayer washing tablets are self-bonded, the semi-finished tablets in the drying stage have a relatively high viscosity and can be closely bonded to another finished tablet. When different types of monolayer washing tablets A and monolayer washing tablets B are bonded to each other, due to the special "saponification layer" effect, they can also achieve a close bonding effect, obtaining a multilayer low-foam washing tablet with good decontamination effect, low foam, and fast dissolution.

[0032] In summary, the present application has the following beneficial effects: 1. The low-foam surfactants such as isomeric alcohol ether sodium sulfate used in the present application not only reduce the amount of foam during the washing process but also accelerate the dissolution rate of the washing tablets. With the combined action of specially selected non-ionic surfactants, anionic surfactants, and film-forming agents, the prepared monolayer washing tablets can have a rich pore structure, ensuring a certain thickness of the washing tablets while having a low-foam effect.

[0033] 2. When the multilayer washing tablets are dissolved in water, fatty acid salts can form a film layer similar to mineral oil on the liquid surface, further reducing the surface tension and promoting dissolution. Description of the Drawings

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

[0035] Figure 2 It is a cross-sectional microscope image of the three-layer low-foam washing tablet of Example 3.

[0036] Figure 3 It is a physical image of the three-layer low-foam washing tablet of Example 3.

[0037] Figure 4 It is a cross-sectional microscope image of the four-layer low-foam washing tablet of Example 6.

[0038] Figure 5 It is a physical image of the single-layer washing tablet A1 of the two-layer low-foam washing tablet of Comparative Example 2.

[0039] Figure 6 It is a diagram of the situation where the single-layer washing tablet B prepared in Comparative Example 7 cannot be formed.

[0040] Figure 7 It is a diagram of the result state of the two-layer washing tablet of Comparative Examples 1-3 in the storage stability test.

[0041] Figure 8 It is a diagram of the result state of the two-layer washing tablet of Comparative Examples 4-6 and Comparative Example 8 in the storage stability test.

[0042] Figure 9 It is a test diagram at 0 min and 5 min in the foam height detection of Examples 1-3.

[0043] Figure 10 It is a test diagram at 0 min and 5 min in the foam height detection of Examples 4-6.

[0044] Figure 11 It is a test diagram at 0 min and 5 min in the foam height detection of Comparative Example 1 and Comparative Examples 4-5.

[0045] Figure 12 It is a test diagram at 0 min and 5 min in the foam height detection of Comparative Example 6. Detailed implementation mode

[0046] The following further describes the present application in detail with reference to the drawings and examples.

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

[0048] The sources of some raw materials are as follows: The alkyl polyglycoside alkoxy compound is purchased from the China National Research Institute of Daily Chemical Industry with the model number APG-NF.

[0049] The isomeric alcohol ether sodium sulfate is purchased from the China National Research Institute of Daily Chemical Industry with the model number CYS-221.

[0050] Sodium modified fatty oil ethoxylate sulfonate was purchased from China National Research Institute of Daily Chemical Industry, with the model number of SNS-80.

[0051] Hydrolyzed wheat protein / silicone copolymer was purchased from Croda Group, Coltide HSI-LQ-(SG).

[0052] Natural phyllosilicate was purchased from BYK Chemie GmbH, with the model number of PURABYK-P 5540.

[0053] EO / PO block polyether was purchased from BASF, with the model number of Pluronic PE 6100 Secondary alcohol ethoxylate was purchased from Dow Chemical, with the model number of ECOSURF TM LF-30 Example

[0054] Example 1 A double-layer low-foam washing tablet is composed of a single-layer washing tablet A1 and a single-layer washing tablet A2 by self-adhesion.

[0055] The single-layer washing tablet A1 was prepared from slurry A1. The slurry A1, by weight percentage, included the following raw materials: 28% polyvinyl alcohol, 30% α-olefin sulfonate, 5% isomeric alcohol ether sulfate, 5% alkyl glycoside alkoxylate, 5% fatty acid methyl ester ethoxylate, 3% lauric acid, 1% citric acid, 1% solid protease, 2% glycerol, 1% essence, 0.1% dye, 18.9% water.

[0056] The single-layer washing tablet A2 was prepared from slurry A2. The slurry A2, by weight percentage, included the following raw materials: 25% polyvinyl alcohol, 17% fatty acid methyl ester sulfonate, 10% α-olefin sulfonate, 3% fatty acid methyl ester ethoxylated sulfonate, 3% isooctyl sulfate, 6% secondary alcohol ethoxylate, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% essence, 23% water.

[0057] After testing, the optimal thickness of the single-layer washing tablet A is 0.3 - 3.5 mm, and the optimal thickness of the single-layer washing tablet B is 0.3 - 3.0 mm. The amount of slurry used can be set according to the actual situation to obtain a single-layer washing tablet with the corresponding thickness.

[0058] This example also provides a preparation method for the double-layer low-foam washing tablet, 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 80°C. After the polyvinyl alcohol swells evenly, add α-olefin sulfonate and isomeric alcohol ether sulfate, stir and dissolve evenly, and stop heating.

[0059] Step 1b: Sequentially add an alkyl polyglycoside alkoxylate, a fatty acid methyl ester ethoxylate, lauric acid, citric acid, glycerol, essence, and dye, and stir to dissolve evenly to obtain slurry A1.

[0060] Step 2: Prepare slurry A2, including the following steps: Step 2a: Mix water and polyvinyl alcohol and stir and heat to 80 °C. After the polyvinyl alcohol swells evenly, add sodium fatty acid methyl ester ethoxylate sulfonate, sodium fatty acid methyl ester sulfonate, α-olefin sulfonate, and sodium isooctyl sulfate, and stir to dissolve evenly, then stop heating.

[0061] Step 2b: Sequentially add an EO / PO block polyether, a secondary alcohol ethoxylate, stearic acid, citric acid, propylene glycol, and essence, and stir to dissolve evenly to obtain slurry A2.

[0062] Step 3: Dry slurry A1 and form it into tablets. When drying and tableting, add solid protease in the form of spraying to obtain a single-layer washing tablet A1.

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

[0064] The semi-dry self-bonding operation can make the layers of the single-layer washing tablets in the double-layer low-foam washing tablet self-bond with a smooth surface of one layer and a rough surface of the other layer.

[0065] The cross-sectional microscope image of the double-layer low-foam washing tablet refers to Figure 1 .

[0066] Example 2 A double-layer low-foam washing tablet is composed of a self-bonding of a single-layer washing tablet A and a single-layer washing tablet B.

[0067] The single-layer washing tablet A is prepared from slurry A. Slurry A includes the following raw materials by weight percentage: 28% polyvinyl alcohol, 20% sodium lauroyl glutamate, 5% isomeric alcohol ether sulfate, 2% alkyl polyglycoside alkoxylate, 3% secondary alcohol ethoxylate, 2% lauric acid, 1% citric acid, 2% butanediol, 1% essence, and 36% water.

[0068] The single-layer washing tablet B is prepared from slurry B. Slurry B includes the following raw materials by weight percentage: 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% essence, and 48% water.

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

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

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

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

[0073] Step 2b: Raise the temperature to 38°C, add sodium alkyl sulfate and octanediol, and stir and dissolve evenly.

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

[0075] Step 3: Dry slurry A, form it into tablets to obtain a single-layer washing tablet A.

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

[0077] Example 3 A three-layer low-foam washing tablet is self-bonded by a single-layer washing tablet A1, a single-layer washing tablet B, and a single-layer washing tablet A2.

[0078] The first layer: The single-layer washing tablet A1 is prepared from slurry A1. According to weight percentage, slurry A1 includes the following raw materials: 20% polyvinyl alcohol, 16% fatty acid methyl ester sulfonate, 7% α-olefin sulfonate, 7% sodium lauroyl glutamate, 5% fatty acid methyl ester ethoxylated sulfonate, 4% isomeric alcohol ether sulfate, 1% isooctyl sulfate, 10% alkyl glycoside alkoxy compound, 5% EO / PO block polyether, 3% secondary alcohol ethoxylate, 5% oleic acid, 1% gluconic acid, 2% hexanediol, 1% essence, 13% water.

[0079] Second layer: The single-layer washing sheet B is prepared from slurry B. The slurry B, by weight percentage, comprises the following raw materials: 4% sodium alginate, 4% carboxymethyl cellulose, 15% modified fatty oil ethoxylate sulfonate, 13% α-olefin sulfonate, 5% natural phyllosilicate, 5% sodium carbonate, 2% glycerol, 1% essence, 0.1% dye, 1% solid protease, and 49.9% water.

[0080] Third layer: The single-layer washing sheet A2 is prepared from slurry A2. The slurry A2, by weight percentage, comprises the following raw materials: 18% polyvinyl alcohol, 23% sodium lauroyl glutamate, 5% 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% essence, and 36.5% water.

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

[0082] Step 1b: Sequentially add alkyl glycoside alkoxylate, EO / PO block polyether, secondary alcohol ethoxylate, oleic acid, gluconic acid, hexanediol, and essence, and stir to 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 it stand at 30°C to fully swell into a homogeneous viscous liquid.

[0084] Step 2b: Heat to 45°C, and add modified fatty oil ethoxylate sulfonate, α-olefin sulfonate, and glycerol, and stir to dissolve evenly.

[0085] Step 2c: Continuously add natural phyllosilicate, sodium carbonate, essence, and dye, and stir to dissolve evenly to obtain slurry B.

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

[0087] Step 3b: Sequentially add EO / PO block polyether, fatty acid methyl ester ethoxylate, secondary alcohol ethoxylate, alkyl glycoside alkoxylate, palmitic acid, citric acid, propylene glycol, and essence, and stir until dissolved evenly.

[0088] Step 3c: Cool down to 60 °C, and continue to add liquid protease and stir evenly to obtain slurry A2.

[0089] Step 4: Dry slurry A1 and form it into tablets to obtain single-layer washing tablet A1.

[0090] Step 5: Dry slurry B to form it into tablets.

[0091] When drying and forming the tablets, add solid protease in the form of spraying.

[0092] After spraying solid protease and when slurry B is dried to semi-dry, attach single-layer washing tablet A1 to the surface of semi-formed single-layer washing tablet B, and continue to dry to obtain self-adhesive single-layer washing tablet A1 and single-layer washing tablet B.

[0093] The self-adhesive single-layer washing tablet A1 and single-layer washing tablet 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 semi-formed single-layer washing tablet A2, and continue to dry to obtain a three-layer low-foam washing tablet.

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

[0096] The cross-sectional microscopic image of the three-layer low-foam washing tablet refers to Figure 2 , and obvious holes can be seen. The physical image of the three-layer low-foam washing tablet refers to Figure 3 .

[0097] Example 4 A three-layer low-foam washing tablet is composed of self-adhesive single-layer washing tablet A1, single-layer washing tablet B, and single-layer washing tablet A2.

[0098] The difference from Example 3 is that the contents of some raw materials in slurry B of the second layer are different. Specifically, slurry B includes the following raw materials by weight percentage: 10% sodium alginate, 1% carboxymethyl cellulose, 15% modified oil ethoxylate sulfonate, 13% α-olefin sulfonate, 5% natural phyllosilicate, 5% sodium carbonate, 2% glycerol, 1% essence, 0.1% dye, 1% solid protease, and 46.9% water.

[0099] Example 5 A three-layer low-foam washing tablet is composed of self-adhesive single-layer washing tablet A1, single-layer washing tablet A3, and single-layer washing tablet A2.

[0100] It is different from Example 3 in that the second layer is a single-layer washing sheet A3.

[0101] The single-layer washing sheet A3 is prepared from slurry A3. According to the weight percentage of slurry A3, it includes the following raw materials: 15% polyvinyl alcohol, 13% sodium lauroyl glutamate, 5% α-olefin sulfonate, 2.5% 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% essence, 0.1% dye, and 50.9% water.

[0102] Moreover, in the preparation method of the three-layer low-foam washing sheet, step 2 becomes 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 α-olefin sulfonate, sodium lauroyl glutamate, and isomeric alcohol ether sulfate, and stir to dissolve evenly, then stop heating.

[0103] Step 2b: Sequentially add alkyl glycoside alkoxylate, fatty acid methyl ester ethoxylate, EO / PO block polyether, secondary alcohol ethoxylate, lauric acid, citric acid, glycerol, essence, and dye, and stir to dissolve evenly to obtain slurry A3.

[0104] Example 6 A four-layer low-foam washing sheet is self-bonded by a single-layer washing sheet A1, a single-layer washing sheet B1, a single-layer washing sheet B2, and a single-layer washing sheet A2. The first layer and the second layer are the same as those in Example 3, and the fourth layer is basically the same as the third layer in Example 3.

[0105] The difference between the fourth layer and the third layer in Example 3 is that 0.1% of dye is added to the fourth layer, and the amount of water used is correspondingly reduced by 0.1%. This is only for easily distinguishing the layers and does not affect the actual efficacy.

[0106] The slurry of the third-layer single-layer washing sheet B2 is composed of the following raw materials: 14% sodium alginate, 1% carboxymethyl cellulose, 15% fatty acid methyl ester sulfonate, 5% α-olefin sulfonate, 5% natural phyllosilicate, 5% sodium carbonate, 2% glycerol, 1% essence, and 52% water.

[0107] A preparation method of a four-layer low-foam washing sheet includes the following steps: Step 1: Prepare slurry A1, which includes the following steps: Step 1a: Mix water and polyvinyl alcohol, stir and heat to 85°C. After the polyvinyl alcohol swells evenly, add sodium methyl ester sulfonate, α-olefin sulfonate, sodium lauroyl glutamate, sodium ethoxylated methyl ester sulfonate, isomeric alcohol ether sulfate, and sodium isooctyl sulfate, stir and dissolve evenly, then stop heating.

[0108] Step 1b: Sequentially add alkyl glycoside alkoxy compound, EO / PO block polyether, secondary alcohol ethoxylate, oleic acid, gluconic acid, hexanediol, and essence, 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 it stand at 30°C to fully swell into a homogeneous viscous liquid.

[0110] Step 2b: Raise the temperature to 45°C, add sodium ethoxylated modified grease sulfonate, α-olefin sulfonate, and glycerol, stir and dissolve evenly.

[0111] Step 2c: Continuously add natural foliated silicate, sodium carbonate, essence, 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 it stand at 30°C to fully swell into a homogeneous viscous liquid.

[0113] Step 3b: Raise the temperature to 45°C, add sodium methyl ester sulfonate, α-olefin sulfonate, and glycerol, stir and dissolve evenly.

[0114] Step 3c: Continuously add natural foliated silicate, sodium carbonate, essence, 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, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium methyl ester sulfonate and sodium isooctyl sulfate, stir and dissolve evenly, then stop heating.

[0116] Step 4b: Sequentially add EO / PO block polyether, sodium ethoxylated methyl ester, secondary alcohol ethoxylate, alkyl glycoside alkoxy compound, palmitic acid, citric acid, propylene glycol, and essence, stir and dissolve evenly.

[0117] Step 4c: Cool down to 60°C, continuously add liquid protease and stir evenly to obtain slurry A2.

[0118] Step 5: Dry slurry A1, form it into tablets to obtain single-layer washing tablet A1.

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

[0120] When drying and forming tablets, add solid protease in the form of spraying.

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

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

[0123] Step 7: When drying the 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 tablets to obtain the second semi-finished product.

[0124] 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 the slurry A2, attach the second semi-finished product obtained in Step 7 to the surface of the semi-formed single-layer washing sheet A2, and continue drying to obtain a four-layer low-foam washing sheet.

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

[0127] The cross-sectional microscope image of the four-layer low-foam washing sheet refers to Figure 4 .

[0128] Comparative example Comparative example 1 A double-layer laundry sheet, comprising two layers of single-layer laundry sheets adhered by liquid protease and an adhesive.

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

[0130] The preparation method of the single-layer laundry sheet comprises the following steps: Add polyvinyl alcohol and deionized water to the batching pot, stir and pre-dissolve for 30 min, control the temperature at 60 °C until completely dissolved.

[0131] Add sodium dodecylbenzenesulfonate, α-olefin sulfonate, fatty alcohol polyoxyethylene ether, glycerol, sodium citrate and pigment to the batching pot, control the temperature of the batching pot at 80 °C, and stir for 50 min to obtain a uniform slurry.

[0132] Transfer the slurry to a drying cylinder at 100 °C and dry it to make a single-layer laundry sheet.

[0133] A method for preparing a double-layer laundry sheet, comprising the following steps: Take two single-layer laundry sheets and apply liquid protease on the surface of each single-layer laundry sheet.

[0134] Use a bonding machine to bond and extrude the above-mentioned single-layer laundry sheets coated with liquid protease together, and then make a double-layer laundry sheet through thermal shearing, stamping, and packaging.

[0135] Comparative Example 2 A double-layer low-foam washing sheet is composed of self-bonding of a single-layer washing sheet A1 and a single-layer washing sheet A2.

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

[0137] The single-layer washing sheet A2 is prepared from slurry A2. Slurry A2, by weight percentage, comprises the following raw materials: 25% polyvinyl alcohol, 30% fatty acid methyl ester ethoxylated sulfonate, 3% isooctyl alcohol sodium sulfate, 6% secondary alcohol ethoxylate, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% essence, 23% water.

[0138] A method for preparing a double-layer low-foam washing sheet, the difference from Example 1 is that: Steps 1 and 2 are partially different, and the rest are the same.

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

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

[0141] Step 2 comprises the following steps: Step 2a: Mix water and polyvinyl alcohol, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium fatty acid methyl ester ethoxylated sulfonate and sodium isooctyl sulfate, stir until dissolved evenly, and then stop heating.

[0142] Step 2b: Sequentially add EO / PO block polyether, secondary alcohol ethoxylate, stearic acid, citric acid, propylene glycol, and essence, stir until dissolved evenly to obtain slurry A2.

[0143] Since neither the single-layer washing tablets A1 nor A2 in this comparative example used high-foaming surfactants, the single-layer forming was very poor. During tablet production, the slurry flowed back, forming waterfall marks. Moreover, the single-layer washing tablets were very thin and easily floated in water, resulting in slow dissolution.

[0144] The physical picture of the single-layer washing tablet A1 is referred to Figure 5 。

[0145] Comparative Example 3 A double-layer low-foaming washing tablet, which is different from Example 1 in that sodium dodecylbenzenesulfonate is used to equally replace α-olefin sulfonate in both the single-layer washing tablets A1 and A2.

[0146] Comparative Example 4 A double-layer low-foaming washing tablet is composed of self-adhesive single-layer washing tablets A1 and A2.

[0147] It is different from Example 1 in that there are some differences in the raw materials of slurry A1 and slurry A2, specifically as follows: The single-layer washing tablet A1 is prepared from slurry A1. Slurry A1 includes the following raw materials by weight percentage: 28% polyvinyl alcohol, 35% α-olefin sulfonate, 5% alkyl glycoside alkoxylate, 5% fatty acid methyl ester ethoxylate, 3% lauric acid, 1% citric acid, 1% liquid protease, 2% glycerol, 1% essence, 0.1% dye, 18.9% water.

[0148] The single-layer washing tablet A2 is prepared from slurry A2. Slurry A2 includes the following raw materials by weight percentage: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 13% α-olefin sulfonate, 3% sodium isooctyl sulfate, 6% secondary alcohol ethoxylate, 7% EO / PO block polyether, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% essence, 23% water.

[0149] A preparation method of a double-layer low-foaming washing tablet, which is different from Example 1 in that Steps 1 and 2 are partially different and the rest are the same.

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

[0151] Step 1b: Add alkyl polyglycoside alkoxy compound, fatty acid methyl ester ethoxylate, lauric acid, citric acid, glycerol, essence, 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, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium fatty acid methyl ester sulfonate, sodium α-olefin sulfonate, and sodium isooctyl sulfate, stir and dissolve evenly, then stop heating.

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

[0154] Comparative Example 5 A double-layer low-foam washing tablet, which is different from Example 1 in that part of the raw materials of slurry A1 and slurry A2 are different, specifically as follows: The single-layer washing tablet A1 is prepared from slurry A1. Slurry A1 includes the following raw materials by weight percentage: 28% polyvinyl alcohol, 30% sodium α-olefin sulfonate, 5% isomeric alcohol ether sulfate, 3% lauric acid, 1% citric acid, 1% solid protease, 2% glycerol, 1% essence, 0.1% dye, 28.9% water.

[0155] The single-layer washing tablet A2 is prepared from slurry A2. Slurry A2 includes the following raw materials by weight percentage: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 10% sodium α-olefin sulfonate, 3% fatty acid methyl ester ethoxylated sulfonate, 3% sodium isooctyl sulfate, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% essence, 36% water.

[0156] A preparation method of a double-layer low-foam washing tablet, which is different from Example 1 in that Steps 1 and 2 are partially different, and the rest are the same.

[0157] Specifically, Step 1 includes the following steps: Mix water and polyvinyl alcohol, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium α-olefin sulfonate, isomeric alcohol ether sulfate, lauric acid, citric acid, glycerol, essence, and dye, stir and dissolve evenly to obtain slurry A1.

[0158] Step 2: Prepare slurry A2, which includes the following steps: Mix water and polyvinyl alcohol, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium fatty acid methyl ester ethoxylate sulfonate, sodium fatty acid methyl ester sulfonate, α-olefin sulfonate, sodium isooctyl sulfate, stearic acid, citric acid, propylene glycol, and essence, and stir to dissolve evenly to obtain slurry A2.

[0159] Comparative Example 6 A double-layer low-foam washing tablet is composed of a single-layer washing tablet A1 and a single-layer washing tablet A2 which are self-bonded.

[0160] The difference from Example 1 is that there are some differences in the raw materials of slurry A1 and slurry A2, specifically as follows: The single-layer washing tablet A1 is prepared from slurry A1. According to weight percentage, slurry A1 includes the following raw materials: 28% polyvinyl alcohol, 30% α-olefin sulfonate, 5% isomeric alcohol ether sulfate, 5% alkyl glycoside, 5% fatty alcohol polyoxyethylene ether, 3% lauric acid, 1% citric acid, 1% liquid protease, 2% glycerol, 1% essence, 0.1% dye, and 18.9% water.

[0161] The single-layer washing tablet A2 is prepared from slurry A2. According to weight percentage, slurry A2 includes the following raw materials: 25% polyvinyl alcohol, 17% sodium fatty acid methyl ester sulfonate, 10% α-olefin sulfonate, 3% sodium fatty acid methyl ester ethoxylate sulfonate, 3% sodium isooctyl sulfate, 13% coconut oil fatty acid diethanolamide, 2% stearic acid, 1% citric acid, 2% propylene glycol, 1% essence, and 23% water.

[0162] A preparation method of a double-layer low-foam washing tablet is different from that of Example 1 in that: Steps 1 and 2 are partially different, and the rest are the same.

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

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

[0165] Step 2: Prepare slurry A2, which includes the following steps: Step 2a: Mix water and polyvinyl alcohol, stir and heat to 80°C. After the polyvinyl alcohol swells evenly, add sodium fatty acid methyl ester ethoxylate sulfonate, sodium fatty acid methyl ester sulfonate, α-olefin sulfonate, and sodium isooctyl sulfate, and stir to dissolve evenly, then stop heating.

[0166] Step 2b: Sequentially add coconut fatty acid diethanolamide, stearic acid, citric acid, propylene glycol, and essence, and stir to dissolve evenly to obtain slurry A2.

[0167] Comparative Example 7 A double-layer low-foam washing tablet is composed of a single-layer washing tablet A and a single-layer washing tablet B that are self-adhered.

[0168] The difference from Example 2 is that the composition of the single-layer washing tablet B is adjusted: The single-layer washing tablet B is prepared from slurry B. According to weight percentage, slurry B 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% essence, and 48% water.

[0169] A preparation method of a double-layer low-foam washing tablet, the difference from Example 2 is that: Part of Step 2 is different.

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

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

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

[0173] When drying slurry B alone to prepare the single-layer washing tablet B, it was found that it could not be formed. The actual situation is referred to Figure 6 .

[0174] Therefore, the corresponding double-layer low-foam washing tablet cannot be obtained in this comparative example, and subsequent tests cannot be carried out.

[0175] Comparative Example 8 A double-layer low-foam washing tablet is composed of a single-layer washing tablet A and a single-layer washing tablet B that are self-adhered.

[0176] The difference from Example 2 is that the composition of the single-layer washing tablet B is adjusted: The single-layer washing tablet B is prepared from slurry B. According to weight percentage, slurry B includes the following raw materials: 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-foam washing tablet, the difference from Example 2 is that: Part of Step 2 is different, and the rest are 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: Heat up to 38°C, add sodium alkyl sulfate and octylene glycol, and stir until dissolved evenly.

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

[0181] Performance Detection Test Test 1: Detergency Test According to GB / T 13174-2021 "Determination of Detergency and Repeated Wash Performance of Laundry Detergents", the washing water is 250 mg / kg CaCl 2 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] Using 0.2% standard laundry detergent as a control, cut the sample into small pieces of equal area (2 cm * 2 cm), prepare a sample solution with 1 L of hard water, and obtain the detergency ratio Pi.

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

[0184] Among them, when Pi ≥ 1.0, it is qualified; when Pi < 1.0, it is unqualified.

[0185] ΔA is the whiteness difference of the test cloth piece before and after washing with the laundry sheet ΔB is the whiteness difference of the test cloth piece before and after washing with the standard laundry detergent Table 1 Test 2: Storage Stability Place a multi-layer washing sheet in a test environment with a temperature of (25 ± 2)°C and a relative humidity of (50 ± 5)% for 30 days. After the test, separate a multi-layer washing sheet and observe whether it can be completely torn into single-layer washing sheets, and record the results in Table 2.

[0186] The phenomena are divided into complete tearing (the layers can be completely separated without damage), incomplete tearing (the layers can be completely separated but damaged), and unable to tear.

[0187] Table 2 Group Morphology Example 1 Unable to tear open Example 2 Unable to tear open Example 3 Unable to tear open Example 4 Unable to tear open Example 5 Unable to tear open Example 6 Unable to tear open Comparative Example 1 Can be torn open completely Comparative Example 2 Torn open incompletely Comparative Example 3 Torn open incompletely Comparative Example 4 Torn open incompletely Comparative Example 5 Torn open incompletely Comparative Example 6 Torn open incompletely Comparative Example 8 Torn open incompletely Test result status diagrams of double-layer washing tablets of Comparative Examples 1-6 and Comparative Example 8 are referred to Figures 7 - 8 。

[0188] Test Three: Dissolution Time According to QB / T 5779-2023 "Laundry Tablets", place 700 mL of hard water (250 mg / kg calcium chloride) in a 1 L beaker, place it in a water bath environment at (23 ± 2) °C, adjust the stirring speed of the magnetic stirrer, cut the double-layer / multi-layer laundry tablets into square pieces of 3 cm * 3 cm, and vertically throw them into the water at a position 10 cm parallel to the water surface.

[0189] Start timing when the laundry tablet touches the water surface, and stop timing when the sample is completely dispersed in the water to obtain the dissolution time.

[0190] Repeat in parallel 3 times.

[0191] Record the results in Table 3.

[0192] Table 3 Test Four: Foam Height According to GB / T 13173-2021 "Test Methods for Surface Active Agents - Detergents", prepare a 1% solution of the double-layer / multi-layer laundry tablets with 250 mg / L of hard water. Use a Ross foam meter to record the foam heights at 0 and 5 minutes at 40 °C.

[0193] Record the results in Table 4.

[0194] Details of the test are shown in Figures 9 - 12 , corresponding to the starting average value at 0 minute before the test and the average value after 5 minutes after the test.

[0195] Table 4 Group Initial mean value at 0 min (mm) Mean value after 5 min (mm) Example 1 79 37 Example 2 57 11 Example 3 97 14 Example 4 83 20 Example 5 103 45 Example 6 113 77 Comparative Example 1 165 163 Comparative Example 4 170 166 Comparative Example 5 159 154 Comparative Example 6 169 168 According to the test results, the laundry tablets of Examples 1-6 have good detergency, can dissolve quickly, have a firm interlayer bond, have a low amount of foam during cleaning, and their various functions are significantly better than those of Comparative Examples 1-6 and 8.

[0196] This specific embodiment is only an interpretation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to their needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A multi-layer low-foam detergent tablet, characterized in that: It is composed of double or multiple layers of single-layer washing sheets through self-adhesion; Wherein, at least one single-layer washing sheet is a single-layer washing sheet A; The single-layer washing sheet A is prepared from slurry A, which includes the following raw materials according to the weight percentage of slurry A: 10-30% film former A, 20-50% anionic surfactant A, 5-20% nonionic surfactant, 2-10% acidulant, 0.5-3% chelating agent, 0-5% enzyme preparation A, 1-5% auxiliary agent A, 0.5-5% essence A, water; Film former A includes polyvinyl alcohol; The anionic surfactant A includes a high-foaming surfactant and a low-foaming surfactant; the weight ratio of the high-foaming anionic surfactant to the low-foaming anionic surfactant is (3-10): 1 The high foaming anionic surfactant includes at least one of sodium α-olefin sulfonate, sodium fatty acid methyl ester sulfonate, and sodium lauroyl glutamate; The low-foaming anionic surfactant includes at least one of sodium isomeric alcohol ether sulfate, sodium fatty acid methyl ester ethoxylated sulfonate, and sodium isooctyl sulfate; The nonionic surfactant includes at least two of EO / PO block polyether, fatty acid methyl ester ethoxylate, secondary alcohol ethoxylate, and alkyl glycoside alkoxylate.

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

4. The multi-layer low-foam detergent tablet according to claim 3, characterized in that: The acidulant includes C12-C18 fatty acid.

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

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

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

8. The multi-layer low-foam detergent tablet according to claim 3, characterized in that: 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.

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

10. A method for preparing a multi-layer low-foam detergent tablet according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Prepare slurry A, including the following steps: Step 1a: Mix and stir water and film-forming agent A at 75-85°C, and after the film-forming agent is evenly swollen, add anionic surfactant A and stir to dissolve evenly; Step 1b: Continue to add the remaining raw materials of slurry A and stir until uniform to obtain slurry A; Step 2: If a single layer of detergent sheet B is included, prepare slurry B, comprising the following steps: Step 2a: Mix water and film-forming agent B and fully swell to a homogeneous viscous liquid at 20-30°C; Step 2b: Add anionic surfactant B and auxiliary agent B at 38-45°C and stir to dissolve evenly; Step 2c: Continue to add the remaining raw materials of slurry B to obtain slurry B; If the single-layer washing sheet B is not included, this step is omitted, and step 3 is performed after step 1; Step 3: When the slurry of any single-layer detergent tablet is dried into tablets, another single-layer or multi-layer detergent tablet that has completed the drying and forming stage is attached, and drying is continued until a multi-layer low-foam detergent tablet is obtained.

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