Bio-enzyme low-temperature stain removal mild laundry detergent based on microcapsule embedding technology

Abstract

The present application belongs to the technical field of washing liquid, and particularly relates to a mild laundry liquid for low-temperature stain removal based on microcapsule embedding technology. The laundry liquid is composed of microcapsules and laundry liquid base liquid. The microcapsules are composed of the following raw materials: a biological enzyme system, a polyol protective agent, a sugar-protein protective agent, a complexing agent, calcium lactate, an interface booster, sodium alginate, a polysaccharide, CaCl2, hydroxyethyl cellulose and PEG-400. The laundry liquid base liquid is composed of the following raw materials: a mild surfactant, a complexing agent, PEG-400, polyvinylpyrrolidone and a thickening agent, and the rest is deionized water. The present application realizes the unification of low-temperature high-efficiency stain removal and mild washing and protection in a four-layer structure. The core phase protects the enzyme and resists the interference of hard water. The double-triggered shell resolves the contradiction between storage stability and fast release in washing, the outer layer promotes the dispersion and mass transfer of the capsule, the mild base liquid reduces the damage to the fabric, and the multiple structures are cooperatively adapted to the low-temperature fast washing scene.

Description

Technical Field

[0001] This invention belongs to the field of detergent technology, specifically relating to a low-temperature stain-removing and mild laundry detergent based on microencapsulation technology. Background Technology

[0002] Modern detergents must simultaneously meet the technical goals of high-efficiency stain removal, low-temperature energy saving, fabric-friendly properties, and environmental sustainability. Bio-enzyme preparations, due to their mild action conditions, high specificity, and biodegradability, are key components in achieving these goals. The combined application of proteases, lipases, and amylases can specifically catalyze the decomposition of protein, grease, and starch stains on clothing, reducing the reliance on high temperatures, high mechanical force, and strongly alkaline chemicals in the washing process, providing core support for low-temperature, energy-saving washing.

[0003] Integrating biological enzymes, especially multi-enzyme complexes, into liquid detergents and maintaining their long-term high efficiency is a major challenge of existing technologies. Specifically, prolonged contact with water molecules in the liquid system and surfactants and ionic components in the formulation can easily lead to changes in the spatial conformation of enzyme proteins and inactivation of active sites, resulting in a significant decrease in enzyme activity over the product's shelf life. In traditional addition methods, enzymes are directly exposed to the washing liquid phase. In complex washing environments such as high-hardness water, calcium and magnesium ions may inhibit enzyme activity, and enzyme molecules are difficult to rapidly accumulate at the fabric-stain interface, resulting in slow onset of action and poor stain removal efficiency in low-temperature quick wash programs. Existing improvement methods include adding excessive stabilizers, using chemically modified enzymes, or developing solid enzyme particles, but none of these methods can achieve an ideal balance between long-term storage stability, rapid release and onset of action during washing, and the overall mildness of the formulation.

[0004] Microencapsulation technology can be a potential solution to the above problems. By physically isolating the active material from the external environment, its storage stability can be significantly improved. However, traditional single-material microcapsules (such as gelatin, gum arabic, etc.) have the following limitations: (1) It is difficult to balance the mechanical strength and permeability of the capsule wall. If the strength is too high, it will be difficult to release during washing, and if it is too low, leakage will easily occur during storage; (2) It lacks intelligent responsiveness to the washing environment (such as ionic strength and mechanical force), and the release behavior is uncontrollable; (3) The dispersibility, wettability and interaction of the capsule with the fabric surface in the washing liquid have not been systematically designed, resulting in low mass transfer efficiency after the release of the active ingredient. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a low-temperature stain-removing and mild laundry detergent based on microencapsulation technology.

[0006] The technical effects described in this invention are achieved through the following technical solution: a low-temperature stain-removing mild laundry detergent based on microcapsule encapsulation technology, which is composed of microcapsules and laundry detergent base liquid; Preferably, the microcapsule comprises the following raw materials in parts by weight: 10-20 parts of a bio-enzyme system, 12-18 parts of a polyol protectant, 4-8 parts of a glycoprotein protectant, 3-6 parts of a complexing agent, 0.3-0.6 parts of calcium lactate, 2-5 parts of an interfacial propellant, 10-16 parts of sodium alginate, 4-8 parts of chitosan, 1-2 parts of CaCl2, 2-4 parts of hydroxyethyl cellulose, and 1-3 parts of PEG-400; It should be noted that the weight parts of the microcapsules are the weight parts of the solid components of the microcapsules, and the water used in the preparation process is not included in the weight parts; Preferably, the laundry detergent base comprises the following raw materials in parts by weight: 16-24 parts mild surfactant, 1-2.5 parts complexing agent, 3-6 parts PEG-400, 0.4-0.8 parts polyvinylpyrrolidone and 0.6-1.2 parts thickener, with the balance being deionized water, to a total weight of 100 parts. Preferably, the biological enzyme system is composed of alkaline protease, lipase and amylase in a mass ratio of 2-4:1-2:1; Preferably, the alkaline protease activity is 2 × 10⁻⁶. 5 ~2×10 6 U / g; Preferably, the lipase activity is 1×10⁻⁶. 4 ~5×10 5 U / g; Preferably, the amylase activity is 1×10⁻⁶. 5 ~1×10 6 U / g; Preferably, the polyol protectant is any one of glycerol, propylene glycol, and sorbitol; Preferably, the glycoprotein protectant is any one of trehalose, sucrose, maltodextrin, and whey protein; Preferably, the complexing agent is any one of sodium gluconate, sodium citrate, and tetrasodium diacetate of glutamate; Preferably, the interface booster is composed of alkyl glycoside and cocamidopropyl betaine in a mass ratio of 1:0.3 to 0.5; Preferably, the mild surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, cocamidopropyl betaine, and sodium fatty alcohol polyoxyethylene ether sulfate; Preferably, the thickener is any one of xanthan gum, hydroxypropyl methylcellulose, and hydroxypropyl cellulose; Preferably, the preparation of the mild laundry detergent specifically includes the following steps: S1: At room temperature, add the polyol protectant to 60-80 parts of deionized water, stir at 400-600 rpm for 10-15 min, add the sugar-protein protectant and complexing agent in sequence, adjust the pH to 7.2-7.8 with sodium citrate-citric acid buffer, reduce the stirring speed to 200-300 rpm, add the biological enzyme system and calcium lactate, then add the interfacial promoter, stir and mix evenly to obtain core phase A; S2: Add 10-20% of the total weight of hydroxyethyl cellulose and PEG-400 to 40-60 parts of deionized water, stir to dissolve evenly, and slowly add the core phase A from step S1 dropwise under stirring at 800-1200 rpm to form particles of size D. 50 Core particles ranging from 150 to 250 μm; S3: Add sodium alginate to deionized water, stir and dissolve evenly to obtain a 1-2 wt% sodium alginate solution; then slowly add the core microparticles from step S2, stir and disperse evenly, add 2-4 wt% CaCl2 solution dropwise, let stand for 20-30 min for cross-linking, filter, and obtain the inner shell capsule slurry. S4: Add chitosan to deionized water, stir to dissolve evenly, adjust the pH to 4.5-5.5 with lactic acid to obtain a 2-4 wt% chitosan solution; then add the inner shell capsule slurry from step S3, stir to mix evenly, filter, and let stand for 2-4 hours to obtain the composite trigger shell capsule slurry. S5: Add the remaining weight of hydroxyethyl cellulose and PEG-400 to 30-50 parts of deionized water, stir to dissolve evenly, add the composite trigger shell capsule slurry from step S4, stir to mix evenly, pass through a 100-200 mesh sieve, adjust the solid content to 20-25 wt%, and obtain the microcapsule slurry. S6: Add complexing agent, PEG-400 and polyvinylpyrrolidone to deionized water in sequence, stir and dissolve evenly, then add mild surfactant and thickener in sequence, stir until the viscosity is stable, adjust the pH to 7-8 with sodium citrate-citric acid buffer, add the microcapsule slurry from step S5, stir and mix evenly, degas under vacuum to obtain mild laundry detergent. Preferably, in step S6, the microcapsule slurry accounts for 2 to 4 wt% of the finished product.

[0007] The beneficial effects of this invention are as follows: This invention achieves a balance between highly efficient stain removal and gentle washing and care under low-temperature conditions through an overall architecture consisting of an enzyme-active core phase, a dual-trigger composite shell, an outer wetting and dispersion layer, and a mild surfactant base solution. Specifically, in the core phase, polyol protectants and sugar-protein protectants synergistically construct a hydration protection and conformational stability environment. Buffer salts (sodium citrate-citric acid buffer) and complexing agents provide a suitable microenvironment locally and weaken hard water ion interference, ensuring the bio-enzyme system maintains high effectiveness during both storage and use. Simultaneously, interface promoters and the bio-enzyme system work synergistically within the same microenvironment. First, wetting and interface regulation reduce the mass transfer resistance of oil and sebum films. Then, the bio-enzyme system directionally breaks down protein, starch, and lipid stains, reducing the dependence of the stain removal process on high temperatures and strong alkalis under low-temperature conditions. Mechanistically, this approach balances low-temperature rapid washing efficiency with fabric-friendliness.

[0008] Furthermore, this invention effectively resolves the conflict between shelf-life stability and rapid onset of action during the washing period through a dual-trigger composite shell structure. Sodium alginate forms a stable network through calcium salt cross-linking, while secondary chitosan deposition makes the shell layer more complete and reduces leakage. This isolates the bio-enzyme system from factors that may cause inactivation in the base solution during storage, reducing activity decay due to long-term contact. Upon entering the washing system, changes in solution ionic strength and mechanical tumbling friction work together to cause swelling, embrittlement, and permeation channels in the shell layer, promoting the controlled release and rapid diffusion of the active ingredient to the contaminated interface. This design allows the microcapsules to maintain stable carrier properties within the bottle, transforming them into a highly efficient release source during washing. This distributes the conflict between stability and onset of action across different stages, avoiding sacrificing onset of action at low temperatures and short programs for stability, and also avoiding introducing leakage and performance degradation during storage for rapid release.

[0009] Hydroxyethyl cellulose and PEG form a hydrophilic wetting and dispersion structure on the outer layer of the capsule, enabling the microcapsules to be rapidly wetted and evenly dispersed after entering water. This reduces the risk of uneven release and pumping difficulties caused by aggregation, sedimentation, and localized concentration unevenness, and also enhances the spreadability of the microcapsules on the detergent and fabric surface. The hydrophilic properties of the outer layer also improve the mass transfer efficiency after triggering, allowing the active ingredients to reach the stained area more easily in a short time, enhancing the efficiency of the process of wetting, breaking down, and then carrying away the product in low-temperature quick wash scenarios. The outer structure and the inner trigger shell work together to reduce the tendency of mechanical capsule rupture and leakage during storage, while improving rapid dispersion and accessibility during washing, forming a synergistic gain between structural layers. Hard water ions can lead to decreased surfactant efficiency, increased dirt redeposition, and interference with the performance of biological enzyme systems. This solution focuses on embedding buffering and complexation into the core phase of the capsule, allowing key reactions to occur in a more favorable local environment. At the same time, the laundry detergent base uses a mild surfactant system combined with appropriate complexing and dispersing components to achieve basic stain removal and rinsing friendliness, reducing dependence on strong alkaline or strong oxidizing systems, thereby reducing the risk of irritation and fabric damage. Attached Figure Description

[0010] Figure 1 The graph shows the sedimentation index results of accelerated stability tests of laundry detergents in Examples 1-3 and Comparative Examples 1-4. Figure 2 The graph shows the stratification index results of the accelerated stability test of the laundry detergents in Examples 1-3 and Comparative Examples 1-4. Figure 3 The graph shows the enzyme activity retention rate after 28 days of accelerated stability testing of laundry detergents in Examples 1-3 and Comparative Examples 1-4. Figure 4 The graph shows the relative release rate results of laundry detergents in Example 1 and Comparative Examples 2-4 under soft water without glass beads test conditions; Figure 5 The graph shows the relative release rate results of laundry detergents in Example 1 and Comparative Examples 2-4 under soft water with glass beads. Figure 6 The graph shows the relative release rate results of laundry detergents in Example 1 and Comparative Examples 2-4 under hard water without glass beads test conditions; Figure 7 The graph shows the relative release rate of laundry detergents in Example 1 and Comparative Examples 2-4 under hard water conditions with glass beads. Detailed Implementation

[0011] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the raw materials involved in the present invention are all purchased through conventional commercial channels. Experimental methods without specific conditions are conventional methods and conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

[0012] Example 1: A low-temperature stain-removing mild laundry detergent based on microencapsulation technology, which is composed of microcapsules and laundry detergent base liquid; The microcapsules are composed of the following raw materials in parts by weight: 15 parts of bio-enzyme system, 15 parts of polyol protectant, 6 parts of glycoprotein protectant, 4 parts of complexing agent, 0.4 parts of calcium lactate, 4 parts of interfacial propellant, 13 parts of sodium alginate, 6 parts of chitosan, 1.5 parts of CaCl2, 3 parts of hydroxyethyl cellulose and 2 parts of PEG-400. The laundry detergent base comprises the following raw materials by weight: 20 parts mild surfactant, 2 parts complexing agent, 4.5 parts PEG-400, 0.6 parts polyvinylpyrrolidone and 0.8 parts thickener, with the remainder being deionized water, to a total weight of 100 parts. The biological enzyme system consists of alkaline protease, lipase, and amylase in a mass ratio of 3:1.5:1. The alkaline protease activity is 1×10⁻⁶. 6 U / g; The lipase activity is 1×10⁻⁶. 5 U / g; The amylase activity is 5 × 10 5 U / g; The interface booster is composed of alkyl glycoside and cocamidopropyl betaine in a mass ratio of 1:0.4; The preparation of the mild laundry detergent specifically includes the following steps: S1: At room temperature, add glycerol to 70 parts of deionized water, stir at 500 rpm for 12 min, add trehalose and tetrasodium diacetate of glutamate in sequence, adjust the pH to 7.5 with sodium citrate-citric acid buffer, reduce stirring to 250 rpm, add biological enzyme system and calcium lactate, then add interface booster, stir and mix evenly to obtain core phase A; S2: Add 15% of the total weight of hydroxyethyl cellulose and PEG-400 to 50 parts of deionized water, stir to dissolve evenly, and slowly add the core phase A from step S1 dropwise while stirring at 1000 rpm to form particles of size D. 50 The core particles are 180 μm in size; S3: Add sodium alginate to deionized water, stir and dissolve evenly to obtain a 1.5 wt% sodium alginate solution; then slowly add the core particles from step S2, stir and disperse evenly, add 3 wt% CaCl2 solution dropwise, let stand for 25 min for cross-linking, filter, and obtain the inner shell capsule slurry; S4: Add chitosan to deionized water, stir to dissolve evenly, adjust the pH to 5 with lactic acid to obtain a 3wt% chitosan solution; then add the inner shell capsule slurry from step S3, stir to mix evenly, filter, and let stand for 3 hours to obtain the composite trigger shell capsule slurry. S5: Add the remaining weight of hydroxyethyl cellulose and PEG-400 to 40 parts of deionized water, stir to dissolve evenly, add the composite trigger shell capsule slurry from step S4, stir to mix evenly, pass through a 150-mesh sieve, adjust the solid content to 23 wt%, and obtain the microcapsule slurry. S6: Add tetrasodium glutamate diacetate, PEG-400 and polyvinylpyrrolidone to deionized water in sequence, stir and dissolve evenly, then add mild surfactant and hydroxypropyl methylcellulose in sequence, stir until the viscosity is stable, adjust the pH to 7.5 with sodium citrate-citric acid buffer, add the microcapsule slurry from step S5, the microcapsule slurry accounts for 3wt% of the finished product mass, stir and mix evenly, degas under vacuum to obtain mild laundry detergent; The mild surfactant is composed of fatty alcohol polyoxyethylene ether, alkyl glycoside and cocamidopropyl betaine in a mass ratio of 2:1:1.

[0013] Example 2: A low-temperature stain-removing mild laundry detergent based on microencapsulation technology, which is composed of microcapsules and laundry detergent base liquid; The microcapsules are composed of the following raw materials in parts by weight: 20 parts of bio-enzyme system, 18 parts of polyol protectant, 8 parts of glycoprotein protectant, 6 parts of complexing agent, 0.6 parts of calcium lactate, 5 parts of interfacial propellant, 16 parts of sodium alginate, 8 parts of chitosan, 2 parts of CaCl2, 4 parts of hydroxyethyl cellulose and 3 parts of PEG-400. The laundry detergent base comprises the following raw materials by weight: 24 parts mild surfactant, 2.5 parts complexing agent, 6 parts PEG-400, 0.8 parts polyvinylpyrrolidone and 1.2 parts thickener, with the remainder being deionized water, to a total weight of 100 parts. The bio-enzyme system consists of alkaline protease, lipase, and amylase in a mass ratio of 4:1:1. The alkaline protease activity is 2 × 10⁻⁶. 6 U / g; The lipase activity is 5 × 10⁻⁶. 5 U / g; The amylase activity is 1×10 6 U / g; The interface booster is composed of alkyl glycoside and cocamidopropyl betaine in a mass ratio of 1:0.3; The preparation of the mild laundry detergent specifically includes the following steps: S1: At room temperature, add sorbitol to 80 parts of deionized water, stir at 600 rpm for 10 min, add sucrose and sodium gluconate in sequence, adjust the pH to 7.2 with sodium citrate-citric acid buffer, reduce stirring to 300 rpm, add biological enzyme system and calcium lactate, then add interface booster, stir and mix evenly to obtain core phase A; S2: Add 20% by weight of the total weight of hydroxyethyl cellulose and PEG-400 to 60 parts of deionized water, stir to dissolve evenly, and slowly add the core phase A from step S1 dropwise under stirring at 1200 rpm to form particles of size D. 50 The core particles are 150 μm in size; S3: Add sodium alginate to deionized water, stir and dissolve evenly to obtain a 2wt% sodium alginate solution; then slowly add the core particles from step S2, stir and disperse evenly, add 4wt% CaCl2 solution dropwise, let stand for 20 minutes for cross-linking, filter, and obtain the inner shell capsule slurry; S4: Add chitosan to deionized water, stir to dissolve evenly, adjust the pH to 4.5 with lactic acid to obtain a 4wt% chitosan solution; then add the inner shell capsule slurry from step S3, stir to mix evenly, filter, and let stand for 4 hours to obtain the composite trigger shell capsule slurry. S5: Add the remaining weight of hydroxyethyl cellulose and PEG-400 to 30 parts of deionized water, stir to dissolve evenly, add the composite trigger shell capsule slurry from step S4, stir to mix evenly, pass through a 200-mesh sieve, adjust the solid content to 25 wt%, and obtain the microcapsule slurry. S6: Add sodium gluconate, PEG-400 and polyvinylpyrrolidone to deionized water in sequence, stir and dissolve evenly, then add alkyl glycoside and hydroxypropyl cellulose in sequence, stir until the viscosity is stable, adjust the pH to 8 with sodium citrate-citric acid buffer, add the microcapsule slurry from step S5, the microcapsule slurry accounts for 4 wt% of the finished product, stir and mix evenly, degas under vacuum to obtain mild laundry detergent. Example 3: A low-temperature stain-removing mild laundry detergent based on microencapsulation technology, which is composed of microcapsules and laundry detergent base liquid; The microcapsules are composed of the following raw materials in parts by weight: 10 parts of bio-enzyme system, 12 parts of polyol protectant, 4 parts of glycoprotein protectant, 3 parts of complexing agent, 0.3 parts of calcium lactate, 2 parts of interface propellant, 10 parts of sodium alginate, 4 parts of chitosan, 1 part of CaCl2, 2 parts of hydroxyethyl cellulose and 1 part of PEG-400. The laundry detergent base comprises the following raw materials by weight: 16 parts mild surfactant, 1 part complexing agent, 3 parts PEG-400, 0.4 parts polyvinylpyrrolidone and 0.6 parts thickener, with the remainder being deionized water, to a total weight of 100 parts. The biological enzyme system consists of alkaline protease, lipase and amylase in a mass ratio of 3:2:1. The alkaline protease activity is 2 × 10⁻⁶. 5 U / g; The lipase activity is 1×10⁻⁶. 4 U / g; The amylase activity is 1×10 5 U / g; The interface booster is composed of alkyl glycoside and cocamidopropyl betaine in a mass ratio of 1:0.5; The preparation of the mild laundry detergent specifically includes the following steps: S1: At room temperature, propylene glycol is added to 70 parts of deionized water and stirred at 400 rpm for 15 min. Maltodextrin and sodium citrate are added in sequence. The pH is adjusted to 7.2 by sodium citrate-citric acid buffer. The stirring is reduced to 200 rpm. The biological enzyme system and calcium chloride are added. Then the interfacial promoter is added and stirred until homogeneous to obtain core phase A. S2: Add 10% of the total weight of hydroxyethyl cellulose and PEG-400 to 40 parts of deionized water, stir to dissolve evenly, and slowly add the core phase A from step S1 dropwise under stirring at 800 rpm to form particles of size D. 50 The core particles are 150 μm in size; S3: Add sodium alginate to deionized water, stir and dissolve evenly to obtain a 1wt% sodium alginate solution; then slowly add the core particles from step S2, stir and disperse evenly, add 2wt% CaCl2 solution dropwise, let stand for 30 minutes for cross-linking, filter, and obtain the inner shell capsule slurry; S4: Add chitosan to deionized water, stir to dissolve evenly, adjust the pH to 5.5 with lactic acid to obtain a 2wt% chitosan solution; then add the inner shell capsule slurry from step S3, stir to mix evenly, filter, and let stand for 2 hours to obtain the composite trigger shell capsule slurry. S5: Add the remaining weight of hydroxyethyl cellulose and PEG-400 to 50 parts of deionized water, stir to dissolve evenly, add the composite trigger shell capsule slurry from step S4, stir to mix evenly, pass through a 100-mesh sieve, adjust the solid content to 20 wt%, and obtain the microcapsule slurry. S6: Add sodium citrate, PEG-400 and polyvinylpyrrolidone to deionized water in sequence, stir and dissolve evenly, then add cocamidopropyl betaine and xanthan gum in sequence, stir until the viscosity is stable, adjust the pH to 7 with sodium citrate-citric acid buffer, add the microcapsule slurry from step S5, the microcapsule slurry accounts for 2wt% of the finished product mass, stir and mix evenly, degas under vacuum to obtain mild laundry detergent; Comparative Example 1: In Comparative Example 1, no microcapsule encapsulation was performed. Instead, an equivalent amount of effective enzyme was added directly to the base solution in step S6. The remaining raw materials and steps were consistent with those in Example 1.

[0014] Comparative Example 2: Step S4 is not performed in Comparative Example 2; the remaining raw materials and steps are the same as in Example 1.

[0015] Comparative Example 3: Step S5 is not performed in Comparative Example 3; the remaining raw materials and steps are the same as in Example 1.

[0016] Comparative Example 4: No interfacial booster was added in Comparative Example 4; the remaining raw materials and steps were the same as in Example 1.

[0017] Accelerated stability test: 200 mL samples (from Examples 1-3 and Comparative Examples 1-4) were placed in 500 mL bottles and incubated at 40°C for 28 days. Samples were taken on days 0, 7, 14, and 28. After each bottle was removed, it was left to stand for 30 minutes without shaking. The sedimentation index (%) was calculated as: sedimentation layer height / total column height × 100%; stratification index (%) was calculated as: supernatant height / total column height × 100%. After the test, 1.0 mL of the finished product was taken from each bottle after thorough shaking and brought to a final volume of 100 mL with buffer solution. The activities of alkaline protease, lipase, and amylase were measured. Enzyme activity was determined using conventional methods in the art: casein was used as the substrate for protease, p-nitrophenol esters as the substrate for lipase, and soluble starch as the substrate for amylase. The enzyme activity retention rate (%) was calculated as: enzyme activity after the test / enzyme activity before the test × 100% (calculated separately for each of the three enzymes). The results are shown below. Figure 1 , Figure 2 and Figure 3 As shown.

[0018] based on Figure 1-3 Results analysis showed that Examples 1-3 all exhibited excellent stability. Comparative Example 1, by eliminating microcapsule encapsulation, exposed the bio-enzyme system to surfactants, ionic strength, and trace amounts of peroxide / metal ions for extended periods, making it more susceptible to conformational disruption and self-degradation under accelerated conditions at 40°C. Therefore, the enzyme activity retention rate of the three enzymes was significantly reduced. Furthermore, the absence of microcapsule particles in Comparative Example 1 resulted in a sedimentation index close to zero, but this did not necessarily indicate better stability. Instead, it reflected that the stability bottleneck stemmed from enzyme chemical / conformational inactivation rather than particle suspension. Comparative Example 2, by eliminating the secondary deposition of S4 chitosan, retained only sodium alginate / Ca. 2+ In a single-shell microcapsule, the integrity and impermeability of the shell decrease, making it easier for enzymes to leak through the micropores and come into contact with the base liquid during storage, resulting in a decrease in enzyme activity retention. Simultaneously, the single-shell surface is more prone to bridging and aggregation, forming a denser deposition layer, thus increasing sedimentation and stratification indices. In Comparative Example 3, the S5 outer wetting and dispersing layer was removed, resulting in insufficient hydrophilic wetting and steric hindrance protection on the microcapsule surface. This made particles more prone to aggregation and sedimentation, leading to a significant increase in sedimentation and stratification indices. The localized high concentrations and microenvironmental fluctuations caused by aggregation also exacerbated localized leakage and enzyme inactivation, further reducing enzyme activity retention. In Comparative Example 4, after removing the interfacial propellant, the microcapsule structure and isolation mechanism remained intact, and the enzyme activity retention during storage was generally close to that of the previous example, with only a slight deterioration in sedimentation / stratification.

[0019] Trigger Release Test: Two water quality conditions were set for testing: soft water and hard water. Soft water hardness was defined as 50 mg / L CaCO3, and hard water hardness as 350 mg / L CaCO3. 200 mL of working solution (the finished laundry detergent from Example 1 and Comparative Examples 2-4) was taken and kept at a constant temperature for 5 minutes. Magnetic stirring was then started at 300 rpm to simulate washing and tumbling. For the high-friction condition, 20 g of 3 mm diameter glass beads were added to the system to simulate drum friction; for the low-friction condition, no glass beads were added. Starting from the start of stirring, samples were taken sequentially at 0, 1, 3, 5, 10, 15, 20, and 30 minutes. 2.0 mL of the supernatant was taken each time and immediately centrifuged at 2000 g for 2 minutes to remove microorganisms. To avoid measurement deviations caused by particle entrainment, capsule particles were used, and then replenished with the same volume of working solution at the same temperature and formulation to maintain overall volume stability. The activities of protease, lipase, and amylase in the supernatant samples at each time point were measured, and the same method and caliber were used for conversion. The release curve was characterized by relative release rate. The relative release level (%) at each time point was calculated as: enzyme activity at each sampling time point / enzyme activity at the 30-minute sampling time point × 100%. This was used to characterize the release rate and initial onset ability of each sample within the low-temperature rapid wash time window. The results are as follows: Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown.

[0020] based on Figure 4-7The results analysis showed that the release curves of Example 1 under all four operating conditions exhibited a controllable characteristic of gradual release in the initial stage, accelerated release in the middle stage, and a plateau reached within 30 minutes. Furthermore, the initial release rate was faster under high friction and hard water conditions. This demonstrates that the composite trigger shell is more prone to forming swelling / permeation channels under mechanical disturbance and changes in the ionic environment, thus achieving rapid onset of action during the washing period. This characteristic is consistent with the results of the accelerated stability test, which showed lower sedimentation and stratification indices and higher enzyme activity retention, indicating that the system can achieve stable isolation during storage and efficient trigger release during use. In Comparative Example 2, after removing S4, the shell structure became more porous and its anti-leakage ability decreased, resulting in a higher initial release even under low friction conditions, exhibiting a premature release characteristic. This characteristic corroborates the results of the accelerated stability test, which showed increased sedimentation and stratification indices and decreased enzyme activity retention, indicating that a single-layer shell cannot simultaneously meet the dual requirements of isolation during storage and trigger release during the washing period. In Comparative Example 3, after removing the outer wetting and dispersing layer S5, the wetting and dispersion efficiency of the microcapsules decreased, making them prone to aggregation and sedimentation. This resulted in a significant delay in their release process during the first 10-15 minutes under low-friction conditions. This release lag was consistent with the trend of the highest sedimentation index and stratification index in the accelerated stability test, both of which stemmed from the mass transfer limitation and local concentration unevenness caused by aggregation. In Comparative Example 4, after removing the interfacial booster, the structure and triggering mechanism of the microcapsules remained intact, and the release curve was only slightly delayed compared to Example 1. This indicates that the interfacial booster is not the determining factor for the microcapsule's release, but rather its core function is more focused on stain wetting and enhanced interfacial mass transfer during the washing period.

[0021] Stain removal test: Referring to GB / T 13174-2021, standard starch-stained cloth, protein-stained cloth, and sebum-stained cloth test pieces (10cm×10cm) were taken and washed for 20 minutes at 120rpm in a vertical stain removal tester at 15℃. After washing, the cloth pieces were rinsed and dried, and then numbered and randomly grouped to ensure blind evaluation (blind evaluation by ten judges). To verify the robustness to hard water, soft water and hard water were tested separately. The hardness of soft water was defined as 50mg / L CaCO3, and the hardness of hard water was defined as 350mg / L. The CaCO3 meter was used for the washing program, which ran for 15 minutes under quick wash conditions. After washing, the cloth was rinsed twice at the same temperature and hardness, with 500 mL of rinsing water added each time and the cloth tumbled for 2 minutes. After rinsing, the cloth was removed and air-dried at room temperature. Stain removal was rated from 0 to 5 points (5 points: stains are almost completely removed with almost no residue; 4 points: slight residue, acceptable; 3 points: moderate residue, clearly visible; 2 points: heavy residue; 1 point: severe residue; 0 points: almost no improvement). Foam residue was rated from 0 to 5 points (5 points: almost no foam; 4 points: a small amount of foam ring; 3 points: a medium foam layer; 2 points: obvious and persistent foam; 1 point: a lot of foam; 0 points: a lot of foam that is difficult to remove). Subjective rating for hand feel was rated from 0 to 5 points (5 points: refreshing and non-slippery; 4 points: slightly slippery; 3 points: noticeably slippery; 2 points: obviously slippery; 1 point: severely slippery; 0 points: very slippery and sticky). The test results are shown in Tables 1 and 2 below.

[0022] Table 1. Stain Removal Scores of Laundry Detergents in Examples and Comparative Examples under Soft Water Conditions

[0023] Table 2. Stain Removal Scores of Laundry Detergents in Examples and Comparative Examples under Hard Water Conditions

[0024] Based on the analysis of the results in Tables 1 and 2, the embodiment scored the highest overall under soft and hard water and 15°C quick wash conditions, especially showing a more obvious advantage in oily and sebum stains. This is mainly because its composite trigger shell + outer wetting and dispersing layer makes the microcapsules easier to disperse evenly after entering the water and achieve effective release under washing disturbance, which not only avoids inactivation during storage, but also provides sufficient active supply within the quick wash time window.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-temperature stain-removing, mild laundry detergent based on microencapsulation technology, characterized in that, It consists of microcapsules and laundry detergent base; The microcapsules are composed of the following raw materials in parts by weight: 10-20 parts of a bio-enzyme system, 12-18 parts of a polyol protectant, 4-8 parts of a glycoprotein protectant, 3-6 parts of a complexing agent, 0.3-0.6 parts of calcium lactate, 2-5 parts of an interfacial propellant, 10-16 parts of sodium alginate, 4-8 parts of chitosan, 1-2 parts of CaCl2, 2-4 parts of hydroxyethyl cellulose, and 1-3 parts of PEG-400; The laundry detergent base comprises the following raw materials in parts by weight: 16-24 parts mild surfactant, 1-2.5 parts complexing agent, 3-6 parts PEG-400, 0.4-0.8 parts polyvinylpyrrolidone, and 0.6-1.2 parts thickener, with the balance being deionized water, to a total weight of 100 parts.

2. The low-temperature stain-removing and mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The bio-enzyme system consists of alkaline protease, lipase, and amylase in a mass ratio of 2–4:1–2:1; the alkaline protease has an activity of 2 × 10⁻⁶. 5 ~2×10 6 U / g; the lipase activity is 1×10⁻⁶ U / g; 4 ~5×10 5 U / g; the amylase activity is 1×10⁻⁶ U / g; 5 ~1×10 6 U / g.

3. The low-temperature stain-removing mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The polyol protectant is any one of glycerol, propylene glycol, and sorbitol.

4. The low-temperature stain-removing and mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The glycoprotein protectant is any one of trehalose, sucrose, maltodextrin, and whey protein.

5. The low-temperature stain-removing and mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The complexing agent is any one of sodium gluconate, sodium citrate, and tetrasodium diacetate of glutamate.

6. The low-temperature stain-removing mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The interface booster is composed of alkyl glycoside and cocamidopropyl betaine in a mass ratio of 1:0.3 to 0.

5.

7. The low-temperature stain-removing and mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The mild surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, cocamidopropyl betaine, and sodium fatty alcohol polyoxyethylene ether sulfate.

8. The low-temperature stain-removing mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The thickener is any one of xanthan gum, hydroxypropyl methylcellulose, and hydroxypropyl cellulose.

9. The low-temperature stain-removing mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, The preparation of the mild laundry detergent specifically includes the following steps: S1: At room temperature, add polyol protectant to deionized water, stir, add sugar-protein protectant and complexing agent in sequence, adjust pH with sodium citrate-citric acid buffer, reduce stirring speed, add biological enzyme system and calcium lactate, add interface booster, stir and mix evenly to obtain core phase A; S2: Add hydroxyethyl cellulose and PEG-400 to deionized water, stir to dissolve evenly, and slowly add core phase A from step S1 under stirring conditions to obtain core microparticles; S3: Add sodium alginate to deionized water, stir to dissolve evenly, and obtain sodium alginate solution; then slowly add the core particles from step S2, stir to disperse evenly, add CaCl2 solution dropwise, let stand for cross-linking, filter, and obtain inner shell capsule slurry; S4: Add chitosan to deionized water, stir to dissolve evenly, adjust the pH with lactic acid to obtain chitosan solution; then add the inner shell capsule slurry from step S3, stir to mix evenly, filter, and let stand to mature to obtain composite trigger shell capsule slurry; S5: Add hydroxyethyl cellulose and PEG-400 to deionized water, stir to dissolve evenly, add the composite trigger shell capsule slurry from step S4, stir to mix evenly, screen, adjust the solid content, and obtain the microcapsule slurry. S6: Add complexing agent, PEG-400 and polyvinylpyrrolidone to deionized water in sequence, stir and dissolve evenly, then add mild surfactant and thickener in sequence, stir until the viscosity is stable, adjust the pH with sodium citrate-citric acid buffer, add the microcapsule slurry from step S5, stir and mix evenly, degas under vacuum to obtain mild laundry detergent.

10. A low-temperature stain-removing and mild laundry detergent based on microencapsulation technology according to claim 1, characterized in that, In step S6, the microcapsule slurry accounts for 2 to 4 wt% of the finished product.

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