Amino acid surfactant type water cup cleaning agent with neutral pH value

Abstract

The invention relates to the technical field of cleaning agents, and discloses a pH-neutral amino acid surfactant type water cup cleaning agent which comprises the following components in percentage by weight: 10-25% of an amino acid surfactant with the purity of greater than or equal to 98%, 1-5% of a sodium citrate-citric acid buffer pair and 65-85% of deionized water. The amino acid surfactant is selected from at least one of sodium cocoyl glutamate and sodium lauroyl sarcosinate; the weight ratio of the sodium citrate-citric acid buffer pair to the amino acid surfactant is 1: (2-5); the pH value of the cleaning agent is 6.5-7.5, and the contact corrosion rate of the cleaning agent to a glass coating layer and a ceramic glaze surface is smaller than or equal to 0.01 mm / year. By selecting food-grade-sourced active matters, stubborn tea residues and coffee stains can be thoroughly disintegrated, meanwhile, a precise coating, a ceramic glaze surface or a plastic material on the inner wall of the cup is prevented from being damaged, the general cognition that a traditional mild product is insufficient in dirt-removing power is changed, the unification of deep cleaning and great maintenance is realized, and the service life of the cup is prolonged. And the use safety is ensured.

Description

Technical Field

[0001] This invention relates to the field of cleaning agent technology, specifically to a pH-neutral amino acid surfactant-based water cup cleaner. Background Technology

[0002] Drinking utensils such as cups and water bottles are frequently used in daily life. Because they come into direct contact with beverages, their cleanliness directly affects the health of users. Therefore, specialized cleaning agents for these utensils constitute an important product segment in the field of daily chemical products.

[0003] Currently, the technical solutions for cleaning cups and utensils on the market mainly fall into two categories. One category relies on strong alkaline additives such as sodium percarbonate as core ingredients, using oxidation and saponification to break down stubborn stains such as tea stains and coffee stains. The other category consists of general-purpose neutral detergents, which mainly rely on conventional petroleum-based surfactants to emulsify and disperse oil stains and ordinary food residues through their surface activity.

[0004] However, the aforementioned existing technologies have significant drawbacks. While cleaning agents using strong alkaline systems have strong cleaning power, they are also highly corrosive. Long-term use can cause irreversible damage to the internal coating, glaze, and printed patterns of the cups, shortening their lifespan and potentially leading to material migration. They can also irritate the user's skin. On the other hand, while conventional neutral detergents are mild, their targeted cleaning ability is often insufficient for stubborn stains such as dried and polymerized tea stains and coffee stains, resulting in low cleaning efficiency and a poor user experience. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a pH-neutral amino acid surfactant-based cup cleaner, which solves the problem that cleaners often lack targeted cleaning ability, resulting in low cleaning efficiency and a poor user experience.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a pH-neutral amino acid surfactant-based water cup cleaner, comprising the following components by weight percentage: 10-25% amino acid surfactant with a purity ≥98%, 1-5% sodium citrate-citric acid buffer pair, and 65-85% deionized water; The amino acid surfactant is selected from at least one of sodium cocoyl glutamate and sodium lauroyl sarcosinate; the weight ratio of sodium citrate-citric acid buffer pair to amino acid surfactant is 1:2-5; the pH value of the detergent is 6.5-7.5; The contact corrosion rate of the cleaning agent on glass coating and ceramic glaze is ≤0.01mm / year; the emulsification and dispersion rate of tea stains on the inner wall of a water cup at 25℃ is ≥90%; the content of leaching substances from the cleaning agent in food-contact grade plastics PP and PC is ≤5mg / kg; the sodium citrate-citric acid buffer inhibits the hydrolysis rate of amino acid surfactants in a neutral environment by ≤2% / year; and the test conditions are storage at 40℃.

[0007] Preferably, it also includes 0.1-0.5% neutral protease, wherein the neutral protease is Bacillus subtilis neutral protease with an enzyme activity ≥5000 U / g and a pH range of 6.0-8.0; The weight ratio of neutral protease to amino acid surfactant is 1:20-50.

[0008] Preferably, it also includes 0.2-0.8% of a plant-derived anti-fogging agent; Plant-derived antifogging agents are sucrose fatty acid esters with an HLB value of 8-10. The weight ratio of sucrose fatty acid ester to sodium citrate is 1:4-8.

[0009] Preferably, it also includes 0.3-1.0% of a biodegradable thickener, wherein the biodegradable thickener is food-grade hydroxypropyl methylcellulose, and the viscosity of the detergent at 25°C is [missing value]. ; The weight ratio of hydroxypropyl methylcellulose to deionized water is 1:65-283; When plant-derived antifogging agents are also included, the weight ratio of hydroxypropyl methylcellulose to plant-derived antifogging agents is 1:0.2-2.7.

[0010] Preferably, the amino acid surfactant is a compound of sodium cocoyl glutamate and sodium lauroyl sarcosinate in a weight ratio of 1:0.5-2, with a surface tension ≤30mN / m after compounding, and the test condition is 25℃.

[0011] Preferably, the deionized water has a conductivity ≤20μS / cm, the detergent has a pH fluctuation range ≤0.1 after being stored at 0-40℃ for 6 months, and the amino acid surfactant hydrolysis rate is ≤2% / year.

[0012] Preferably, the sodium citrate-citric acid buffer pair ensures that the neutral protease retains ≥85% of its activity after being stored at 0-40°C for 6 months.

[0013] Preferably, the sucrose fatty acid ester forms a hydrophilic film on the glass or ceramic glaze, with a thickness of ≤0.5μm; the sucrose fatty acid ester spreads with the water flow during the cleaning and rinsing stage, and there is no visible residue after the film is formed.

[0014] Preferably, the hydroxypropyl methylcellulose extends the adhesion time of the cleaning agent on the inner wall of the cup to 30 seconds, and the removal rate of coffee stains on the inner wall of the cup is ≥95% at 25°C.

[0015] This invention provides a pH-neutral amino acid surfactant-based water cup cleaner. It has the following beneficial effects: 1. By selecting food-grade active ingredients, this invention can thoroughly break down stubborn tea stains and coffee stains while ensuring that no damage is caused to the precision coating, ceramic glaze or plastic material of the inner wall of the cup. It changes the common perception that traditional mild products are not good at cleaning, and achieves a balance between deep cleaning and careful maintenance, ensuring safe use.

[0016] 2. By constructing a buffer stabilization system, this invention can effectively prevent the core cleaning ingredients from degrading during storage and create an ideal environment for maintaining the activity of highly active biological substances such as proteases added to the formula, significantly delaying their failure process. This achieves a high degree of consistency in product performance throughout the entire shelf life and ensures reliable cleaning results.

[0017] 3. This invention extends the effective action time and achieves a more thorough cleaning effect by simultaneously optimizing the physical properties and additional functions of the formula. It also integrates an innovative anti-fogging function, which can form an ultra-thin hydrophilic film after washing, effectively inhibiting water mist condensation and solving the visual problem when serving hot drinks. Attached Figure Description

[0018] Figure 1 This is a schematic diagram comparing the enzyme activity retention rates of the embodiments and comparative examples of the present invention after accelerated aging tests. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see the appendix Figure 1 This invention provides a pH-neutral amino acid surfactant-based water cup cleaner.

[0021] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0022] Amino acid surfactants include sodium cocoyl glutamate and sodium lauroyl sarcosinate. Sodium cocoyl glutamate has the CAS number 68187-32-6, a purity of ≥98%, is of industrial grade, meets the standards for food contact additives, and has the chemical name N-cocoyl-L-glutamate. Its molecular structure contains a cocoyl group (C12-C18 saturated fatty acyl group) and a sodium glutamate unit, exhibiting a typical amphoteric structure of amino acid surfactants. It should be noted that when the content of amino acid surfactant is less than 10%, its ability to clean stubborn stains decreases significantly, making it difficult to achieve a tea stain removal rate of more than 90%. When it is higher than 25%, the cost increases significantly, the stability of the formulation decreases slightly, and there is no obvious performance gain. Therefore, the preferred range of this invention is 10-25%.

[0023] Sodium lauroyl sarcosinate has the CAS number 137-16-6, a purity of ≥98%, is industrial grade, meets the standards for food contact additives, and its chemical name is sodium N-lauroyl-N-methylglycine. Its molecular structure contains lauroyl (C12 fatty acyl) and sodium sarcosinate units. It has good water solubility and low irritation.

[0024] The pH adjuster is a sodium citrate-citric acid buffer pair, wherein the CAS number of sodium citrate is 68-04-2, the purity is ≥99%, analytical grade, the chemical name is sodium 2-hydroxypropane-1,2,3-tricarboxylate, a white crystalline powder, which is easily soluble in water; Citric acid has the CAS number 77-92-9, a purity of ≥99.5%, is analytical grade, and its chemical name is 2-hydroxypropane-1,2,3-tricarboxylic acid. It is a colorless, transparent crystal, and its aqueous solution is acidic. When the two are mixed in a specific weight ratio, a stable pH buffer system can be constructed.

[0025] The solvent is deionized water, which is prepared in-house using an ion exchange resin method. The conductivity can be adjusted to four levels: 5 μS / cm, 15 μS / cm, 20 μS / cm, and 25 μS / cm. The water contains cations... Content ≤0.1mg / L, anionic The content is ≤0.05mg / L, which meets the purity requirements for water for food contact.

[0026] The functional auxiliary components include neutral protease, plant-derived anti-fogging agent, and biodegradable thickener. The neutral protease is derived from Bacillus subtilis, with CAS number 9014-01-1. It is industrial grade and has two specifications with enzyme activity of 5000 U / g and 8000 U / g. The optimal pH range is 6.0-8.0, the optimal temperature is 30-40℃, and the protein hydrolysis activity is stable. The plant-derived antifogging agent is a sucrose fatty acid ester, CAS number 37318-31-3, food grade, with HLB values ​​of 8 and 10. Its chemical name is an esterification of sucrose and fatty acids (mainly stearic acid and palmitic acid). Its molecular structure contains hydrophilic sucrose units and lipophilic fatty acid units, and it has good surface activity and self-spreading properties. The biodegradable thickener is food-grade hydroxypropyl methylcellulose, CAS number 9004-65-3, industrial grade, with viscosity grades divided into... (25°C, 2% aqueous solution), the repeating unit is the glucose unit of cellulose, wherein the hydroxypropyl group and methoxy The degrees of substitution are 0.2-0.3 and 1.8-2.0, respectively, the number average molecular weight is 100,000-200,000, they have good water solubility and high stability in neutral systems.

[0027] The raw materials used for comparison include common amino acid surfactants, sodium carbonate, nonionic surfactants, and sodium percarbonate. The common amino acid surfactant is sodium cocoyl glutamate, with a purity of 95%, industrial grade, and the same CAS number as the aforementioned high-purity product. Sodium carbonate has the CAS number 497-19-8, a purity of ≥99%, is analytical grade, and its chemical name is sodium carbonate. It is a white powder, and its aqueous solution is strongly alkaline. The nonionic surfactant is fatty alcohol polyoxyethylene ether (AEO-9), CAS number 68439-46-3, industrial grade, chemical name lauryl alcohol polyoxyethylene (9) ether, the molecular structure contains lauryl alcohol unit and 9 oxyethylene units, and has high surface tension. Sodium percarbonate has the CAS number 15630-89-4, a purity of ≥98%, is of industrial grade, and its chemical name is sodium percarbonate. It is a white granule that releases oxygen when it comes into contact with water and has strong oxidizing and alkaline properties.

[0028] (a) Preparation example: Preparation Example 1: Preparation of Sodium Cocoyl Glutamate-Sodium Lauroyl Sarcosinate Complex (weight ratio 1:0.5): Take 100g of sodium cocoyl glutamate and 50g of sodium lauroyl sarcosinate, add 200g of deionized water with a conductivity ≤20μS / cm, place in a 40℃ constant temperature water bath, and stir with an electric stirrer at 300r / min for 30min until the solid is completely dissolved; keep the temperature constant at 40℃ and continue stirring at 300r / min for 15min to eliminate the bubbles generated in the system, and obtain a uniform and transparent complex solution; use a surface tension meter (25℃) to measure the surface tension of the complex solution as 28mN / m, seal and store in a 25℃ environment for later use.

[0029] Preparation Example 2: Preparation of Sodium Cocoyl Glutamate-Sodium Lauroyl Sarcosinate Complex (weight ratio 1:1): Take 100g of sodium cocoyl glutamate and 100g of sodium lauroyl sarcosinate, add 300g of deionized water with a conductivity ≤20μS / cm, place in a 45℃ constant temperature water bath, and stir with an electric stirrer at 350r / min for 40min until the solid is completely dissolved; lower the system temperature to 30℃, and continue stirring at 350r / min for 10min to remove residual bubbles, obtaining a uniform and transparent complex solution; the surface tension of the complex solution was measured to be 26mN / m using a surface tension meter (25℃), and then sealed and stored in a 25℃ environment for later use.

[0030] Preparation Example 3: Preparation of Sodium Cocoyl Glutamate-Sodium Lauroyl Sarcosinate Complex (weight ratio 1:2): Take 100g of sodium coconutyl glutamate and 200g of sodium lauroyl sarcosinate, add 400g of deionized water with a conductivity ≤20μS / cm, place in a 50℃ constant temperature water bath, and stir with an electric stirrer at 400r / min for 50min until the solid is completely dissolved; stop heating and allow the system to cool naturally to room temperature (25℃), and continue stirring at 400r / min for 15min to obtain a uniform and transparent complex solution; use a surface tension meter (25℃) to measure the surface tension of the complex solution as 25mN / m, seal and store in a 25℃ environment for later use.

[0031] (II) Example: Example 1: Preparation of a basic water cup cleaner. By weight percentage, the components are: 10% of the compound from Example 1, 2% sodium citrate-citric acid buffer pair (weight ratio 4:1), and 89% deionized water with a conductivity of 15 μS / cm. The preparation steps are as follows: 89g of deionized water with a conductivity of 15 μS / cm was added to a 500mL reaction vessel. The stirrer was turned on and stirred at 200 rpm. 1g of sodium citrate-citric acid buffer pair (0.67g sodium citrate, 0.33g citric acid) was added to the reaction vessel, and stirring was continued at 200 rpm for 10 minutes until the buffer pair was completely dissolved. The temperature of the system inside the reaction vessel was raised to 35℃, and the mixture was slowly cooled. 10g of the compound from Preparation Example 1 was slowly added to the system while simultaneously increasing the stirring speed to 250r / min and stirring continuously for 25min. After stirring, stirring was continued at 250r / min for 10min. The pH value of the system was measured to be 6.5 using a precision pH meter (accuracy 0.01). The system temperature was lowered to room temperature (25℃), and the mixture was filtered through an organic filter membrane with a pore size of 0.45μm to obtain a basic water cup cleaner. The key performance of the cleaner was initially tested. At 25℃, the contact corrosion rate of the glass coating layer was determined to be 0.008mm / year by gravimetric method, and the emulsification and dispersion rate of tea stains on the inner wall of the water cup was determined to be 91% by spectrophotometry.

[0032] Example 2: Preparation of a water cup cleaner containing neutral protease. By weight percentage, the components were: 15% of the compound from Example 2, 3% sodium citrate-citric acid buffer pair (weight ratio 3:1), 0.3% neutral protease with an enzyme activity of 5000 U / g, and 81.7% deionized water with a conductivity of 10 μS / cm. The preparation steps were as follows: 81.7g of deionized water with a conductivity of 10 μS / cm was added to a 500mL reaction vessel. The stirrer was turned on and stirred at 200 rpm. 3g of sodium citrate-citric acid buffer pair (2.25g sodium citrate, 0.75g citric acid) was added to the reaction vessel, and the mixture was stirred for 10 minutes until the buffer pair was completely dissolved. The system temperature was then lowered to 30°C. 15g of the compound from Preparation Example 2 was added to the reactor and stirred at 250 rpm for 20 min. Then, 0.3g of neutral protease with an enzyme activity of 5000 U / g was added, and the stirring speed was reduced to 150 rpm for 15 min to avoid enzyme inactivation due to high-speed shearing. The pH of the system was measured to be 7.0 using a precision pH meter (accuracy 0.01). The mixture was filtered through an organic filter membrane with a pore size of 0.45 μm to obtain a water cup cleaner containing neutral protease. The key performance of the cleaner was initially tested. At 25°C, the removal rate of milk stains on the inner wall of the water cup was determined to be 92% using a spectrophotometer. After being sealed and stored at 40°C for 1 month, the enzyme activity retention rate of the neutral protease was determined to be 90% using the Folin-phenol method.

[0033] Example 3: Preparation of a water cup cleaner containing an anti-fogging agent. By weight percentage, the components are: 20% of the compound from Example 2, 4% sodium citrate-citric acid buffer pair (weight ratio 4:1), 0.5% sucrose fatty acid ester with HLB value 8, and 75.5% deionized water with conductivity 20 μS / cm. The preparation steps are as follows: 75.5g of deionized water with conductivity 20 μS / cm was added to a 500mL reaction vessel and heated to 40℃. The stirrer was turned on and stirred at 300r / min. 4g of sodium citrate-citric acid buffer pair (3.2g sodium citrate, 0.8g citric acid) was added to the reaction vessel and stirred for 10min until the buffer pair was completely dissolved. 0.5g of sucrose fatty acid ester with HLB value 8 was added to the reaction vessel and stirred at 300r / min. Stir at 0 rpm for 25 min until the sucrose fatty acid esters are completely dissolved and the system becomes transparent. Add 20 g of the compound from Preparation Example 2 to the reaction vessel and continue stirring at 300 rpm for 20 min. Cool the system to room temperature (25 °C) and measure the pH value of the system using a precision pH meter (accuracy 0.01) to 7.2. Filter the solution using an organic filter membrane with a pore size of 0.45 μm to obtain a water cup cleaner containing anti-fogging agent. Perform preliminary tests on the key performance of the cleaner. The thickness of the hydrophilic film formed on the glass surface was measured to be 0.4 μm using a thin film thickness gauge. After cleaning and rinsing, high performance liquid chromatography was used to detect no sucrose fatty acid ester residue. The cleaned glass was placed in alternating environments of 5 °C and 40 °C to measure the anti-fogging effect for 48 h.

[0034] Example 4: Preparation of a water cup cleaner containing a thickener. By weight percentage, the components are: 25% of the compound from Preparation Example 3, 5% sodium citrate-citric acid buffer pair (weight ratio 5:1), and food-grade hydroxypropyl methylcellulose. The preparation steps are as follows: 69.2g of deionized water with a conductivity of 15μS / cm was added to a 500mL reactor. The stirrer was turned on and stirred at 200r / min. 0.8g of food-grade hydroxypropyl methylcellulose was slowly added to the reactor. The temperature of the system in the reactor was raised to 50℃, and the mixture was stirred at 200r / min for 30min until the hydroxypropyl methylcellulose was completely dissolved. The system temperature was then lowered. At 35°C, 5g of sodium citrate-citric acid buffer pair (4.17g sodium citrate, 0.83g citric acid) was added to the reactor and stirred at 200 rpm for 10 min until the buffer pair was completely dissolved. 25g of the compound from Preparation Example 3 was added to the reactor, and the stirring speed was increased to 250 rpm, with stirring continued for 25 min. The pH of the system was measured to be 7.5 using a precision pH meter (accuracy 0.01), and the viscosity of the system was measured to be [missing value]. The system temperature was lowered to room temperature (25℃), and the mixture was filtered through an organic filter membrane with a pore size of 0.45μm to obtain a water cup cleaner containing a thickener. The key performance of the cleaner was initially tested. The adhesion time of the cleaner to the inner wall of the water cup was measured to be 30s using a stopwatch. The removal rate of coffee stains on the inner wall of the water cup was measured to be 96% using a spectrophotometer at 25℃.

[0035] Example 5: Preparation of an all-purpose water cup cleaner. By weight percentage, the components are: 22% of the compound from Example 2, 4.4% sodium citrate-citric acid buffer pair (weight ratio 4:1), 0.3% neutral protease with an enzyme activity of 8000 U / g, 0.7% sucrose fatty acid ester with an HLB value of 10, and food-grade hydroxypropyl methylcellulose (viscosity grade...). 1.0% of deionized water with a conductivity of 12 μS / cm and 72.3% of deionized water were added. The preparation steps were as follows: 72.3 g of deionized water with a conductivity of 12 μS / cm was added to a 500 mL reactor, heated to 45°C, and stirred at 200 r / min. 1.0 g of food-grade hydroxypropyl methylcellulose was added to the reactor and stirred for 35 min until completely dissolved. The system temperature was lowered to 30°C, and 3.5 g of sodium citrate-citric acid buffer (2.625 g of sodium citrate and 0.875 g of citric acid) was added to the reactor and stirred at 200 r / min for 10 min until the buffer was completely dissolved. 0.7 g of sucrose fatty acid ester with an HLB value of 10 was added to the reactor and stirred at 250 r / min for 20 min until completely dissolved. Then, 22 g of the compound from Preparation Example 2 was added and stirred at 250 r / min. Continue stirring at a constant speed for 20 minutes; finally, add 0.5g of neutral protease with an enzyme activity of 8000U / g to the reaction vessel, reduce the stirring speed to 150r / min, and stir at low speed for 15 minutes; the pH value of the system was measured to be 7.1 using a precision pH meter (accuracy 0.01), and the viscosity of the system was measured to be 650mPa・s using a rotational viscometer (25℃); the system temperature was lowered to room temperature (25℃), and filtered using an organic filter membrane with a pore size of 0.45μm to obtain an all-functional water cup cleaner; the key performance of the cleaner was initially tested. Under 25℃ conditions, the removal rates of tea stains, coffee stains, and milk stains were measured to be 94%, 95%, and 93% respectively using a spectrophotometer. The anti-fog effect on the cleaned glass lasted for 48 hours. After being sealed and stored at 40℃ for 6 months, the enzyme activity retention rate of the neutral protease was measured to be 86% using the Folin-phenol method.

[0036] (III) Comparative Example Comparative Example 1: Preparation of an amino acid detergent with an excessively wide pH range. By weight percentage, the components were: 15% sodium cocoyl glutamate (95% purity), 2% sodium carbonate, and 83% deionized water with a conductivity of 25 μS / cm. The preparation steps were the same as in Example 1, specifically: 83g of deionized water with a conductivity of 25 μS / cm was added to a 500mL reactor; the stirrer was turned on and stirred at 200 rpm; 2g of sodium carbonate was added to the reactor; and the mixture was stirred for 10 minutes until completely dissolved; the system temperature was then raised to 3... At 5°C, 15g of sodium cocoyl glutamate with a purity of 95% was added and stirred at 250r / min for 25min. After cooling to room temperature, the pH value of the system was measured to be 8.5 using a precision pH meter. The system was then filtered through an organic filter membrane with a pore size of 0.45μm to obtain an amino acid detergent with an excessively wide pH range. The key difference between this detergent and Example 1 is that it does not contain a sodium citrate-citric acid buffer pair, has a pH value of 8.5 (outside the range of 6.5-7.5), and the purity of the amino acid surfactant is 95% (lower than 98% in Example 1).

[0037] Comparative Example 2: Preparation of a buffer-free amino acid detergent. By weight percentage, the components were 15% of the compound from Preparation Example 2 and 85% of deionized water with a conductivity of 15 μS / cm. The preparation steps were the same as in Example 1, specifically: 85g of deionized water with a conductivity of 15 μS / cm was added to a 500mL reactor, the temperature was raised to 35°C, and then 15g of the compound from Preparation Example 2 was added. The mixture was stirred at 250r / min for 25min. After cooling to room temperature, the natural pH of the system was measured to be 5.8 using a precision pH meter. The mixture was then filtered through an organic filter membrane with a pore size of 0.45μm to obtain a buffer-free amino acid detergent. The key difference between this detergent and Example 1 is that it lacks a sodium citrate-citric acid buffer pair, and the pH value is 5.8 (below the range of 6.5-7.5), making it unable to remain stable in the neutral range.

[0038] Comparative Example 3: Preparation of a water cup cleaner containing a nonionic surfactant. By weight percentage, the components are: 15% fatty alcohol polyoxyethylene ether (AEO-9), 3% sodium citrate-citric acid buffer pair (weight ratio 3:1), and 82% deionized water with a conductivity of 15 μS / cm. The preparation steps are the same as in Example 1, specifically: 82g of deionized water with a conductivity of 15 μS / cm is added to a 500mL reactor, 3g of sodium citrate-citric acid buffer pair is added while stirring, and after dissolution, the temperature is raised to 35℃, 15g of fatty alcohol polyoxyethylene ether is added, and the mixture is stirred for 25min. After cooling to room temperature, the pH value is measured to be 7.0. After filtration, a water cup cleaner containing a nonionic surfactant is obtained. The key difference between this cleaner and Example 1 is that the surfactant type is nonionic (fatty alcohol polyoxyethylene ether), rather than the amino acid surfactant of this invention.

[0039] Comparative Example 4: Preparation of a thickener-free water cup cleaner. By weight percentage, the components were: 25% of the compound from Preparation Example 3, 5% sodium citrate-citric acid buffer pair (weight ratio 5:1), and 70% deionized water with a conductivity of 15 μS / cm. The preparation steps were the same as in Example 4, specifically: 70g of deionized water with a conductivity of 15 μS / cm was added to a reaction vessel, 5g of the buffer pair was added and dissolved, the temperature was raised to 35°C, 25g of the compound from Preparation Example 3 was added, and the mixture was stirred for 25 min. After cooling to room temperature, the pH was measured to be 7.5, and the viscosity was measured using a rotational viscometer (25°C). After filtration, a water cup cleaner without thickener was obtained. The key difference between this cleaner and Example 4 is that it does not contain food-grade hydroxypropyl methylcellulose, has a viscosity of only 100 mPa·s, and its adhesion time to the inner wall of the water cup was measured to be 5 s using a stopwatch.

[0040] Comparative Example 5: Preparation of a water cup cleaner with excessive anti-fogging agent dosage. By weight percentage, the components were: 20% of the compound from Preparation Example 2, 4% sodium citrate-citric acid buffer pair (weight ratio 4:1), 2.0% sucrose fatty acid ester with an HLB value of 8, and 74% deionized water with a conductivity of 20 μS / cm. The preparation steps were the same as in Example 3, specifically: 74g of deionized water with a conductivity of 20 μS / cm was heated to 40°C, 4g of buffer pair was added to dissolve, and then 2.0g of sucrose fatty acid ester was added. Stir to dissolve, then add 20g of the compound from Preparation Example 2 and stir for 20min; after cooling to room temperature, the pH value is measured to be 7.2. After filtration, a water cup cleaner with an excessive amount of anti-fogging agent is obtained; the key difference between this cleaner and Example 3 is that the amount of sucrose fatty acid ester is 2.0% (exceeding the range of 0.2-0.8% of this invention). After cleaning and rinsing, sucrose fatty acid ester residue was detected by high performance liquid chromatography, and the thickness of the hydrophilic film formed on the glass surface was measured to be 1.2μm using a thin film thickness gauge.

[0041] Comparative Example 6: Preparation of a prior art tea stain cleaner. By weight percentage, the components are 10% sodium percarbonate, 5% sodium carbonate, and 85% deionized water (refer to CN102559416A). The preparation steps are as follows: 85g of deionized water is added to a reaction vessel, 5g of sodium carbonate is added and dissolved, then 10g of sodium percarbonate is added and stirred for 20 minutes until completely dissolved. After cooling to room temperature, the pH value of the system is measured to be 10.0 using a precision pH meter. After filtration, the prior art tea stain cleaner is obtained. The key difference between this cleaner and Example 1 is that it does not contain amino acid surfactants and uses alkaline components (sodium percarbonate and sodium carbonate) to construct the system. The pH value is 10.0 (strongly alkaline), which is highly irritating to materials.

[0042] Comparative Example 7: Preparation of a cup cleaner using a conventional phosphate buffer system. By weight percentage, the components were: 20% of the compound from Preparation Example 2, 5% of the disodium hydrogen phosphate-sodium dihydrogen phosphate buffer pair (weight ratio adjusted as needed to achieve pH 7.0), 0.3% of the neutral protease (subtilisin), and 74.7% of deionized water. The preparation steps were the same as in Example 2, specifically: 74.7g of deionized water was added to a reaction vessel, 5g of the phosphate buffer pair was added and stirred to dissolve, then 20g of the compound from Preparation Example 2 was added and stirred for 20min. After cooling to room temperature, 0.3g of neutral protease was added and stirred until homogeneous. The pH of the system was measured to be 7.0 using a precision pH meter. After filtration, a cup cleaner using a conventional phosphate buffer system was obtained. The key difference between this cleaner and Example 2 is that a phosphate buffer pair was used instead of a sodium citrate-citric acid buffer pair to construct the neutral buffer system. Accelerated aging tests of the test examples verified that the phosphate buffer system's protective effect on the neutral protease activity was far inferior to that of the citrate buffer system of the present invention, resulting in a significant decrease in enzyme activity after storage.

[0043] (iv) Test Examples Test Example 1: A test to prove the feasibility of the solution of the present invention. The test object is the water cup cleaner of Examples 1-5. The pH stability test method is to take 50 mL of the samples of each example and store them in a constant temperature environment of 0 °C, 25 °C, and 40 °C for 6 months. Samples are taken once a month, and a precision pH meter (accuracy 0.01) is used to measure the pH value, record the fluctuation range. The evaluation index is that the pH value fluctuation range ≤ 0.1 is qualified. The data is recorded and sorted into a table according to storage temperature, storage time, pH value, and fluctuation range. The results show that when stored at each temperature for 6 months, the pH value fluctuation range of Examples 1-5 is ≤ 0.1, meeting the qualified standard. The material compatibility test method is to select glass-coated cups, ceramic-glazed cups, PP plastic cups, and PC plastic cups (with unified specifications and a surface area of 100 cm²) as test materials. Immerse the samples of each material in 50 mL of the cleaner of each example, place them at a constant temperature of 40 °C for 30 days, take them out, rinse them with deionized water, and use the gravimetric method (accuracy 0.001 g) to measure the corrosion rate of the material surface, and visually observe the appearance change (whether there is loss of luster, scratches, discoloration). The evaluation index is that the corrosion rate ≤ 0.01 mm / year and there is no obvious change in appearance is qualified. The data is recorded and sorted into a table according to cleaner type, material type, corrosion rate, and appearance state. The results show that the corrosion rate of Examples 1-5 for each test material is ≤ 0.01 mm / year, and there is no obvious change in appearance, meeting the qualified standard. The leachable substance safety test method is to refer to GB4806.1-2016 "General Safety Requirements for Food Contact Materials and Articles". Contact the cleaner of each example with PP and PC plastic cups at 60 °C for 24 h, and use a gas chromatography-mass spectrometry (GC-MS) to measure the content of leachable substances. The evaluation index is that the content of leachable substances ≤ 5 mg / kg is qualified. The data is recorded and sorted into a table according to cleaner type, contact material, total amount of leachable substances, main components and content of leachable substances. The results show that the content of leachable substances of Examples 1-5 is ≤ 5 mg / kg, meeting the qualified standard. The basic cleaning power test method is to prepare three kinds of stain samples. The tea stain sample is obtained by soaking a glass cup in black tea (5 g / 100 mL boiling water) for 24 h and then drying it. The coffee stain sample is obtained by soaking a ceramic cup in black coffee (8 g / 100 mL boiling water) for 24 h and then drying it. The milk stain sample is obtained by smearing the inner wall of a PP cup with pure milk (10 mL) and drying it at 60 °C for 2 h. Take 20 mL of the cleaner of each example, add 80 mL of deionized water for dilution, soak the corresponding contaminated water cup for 10 min, gently wipe it with a soft cloth and then rinse it. Use a spectrophotometer to measure the absorbance of the stain before and after cleaning, calculate the removal rate. The evaluation index is that the emulsification and dispersion rate of tea stains and coffee stains ≥ 90% and the removal rate of milk stains ≥ 90% is qualified. The data is recorded and sorted into a table according to cleaner type, stain type, and removal rate. The results show that the removal rate of Examples 1-5 for the three kinds of stains is ≥ 90%, meeting the qualified standard.Test Example 2: Comparison test between the examples and comparative examples. The pH fluctuation comparison test objects were Examples 1, 2, and 5 and Comparative Examples 1 and 2. The test method was the same as the pH stability test in Test Example 1, with an additional test node of 12 months of storage at 40℃. The comparison indicators were pH value, fluctuation range, and whether it met the neutral range of 6.5-7.5 under different storage times. The data records were organized into a comparison table according to sample type (example / comparative example), storage time, pH value, fluctuation range, and whether it met the standard. The results showed that the pH value of Examples 1, 2, and 5 remained at 6.5-7.5 after 12 months of storage at 40℃, with a fluctuation range ≤0.15. The pH values ​​of Comparative Example 1 (pH 8.5) and Comparative Example 2 (pH 5.8) rose to 9.0 and fell to 5.2 respectively after 3 months of storage, both exceeding the neutral range. This proves that the sodium citrate-citric acid buffer pair and pH limit of the present invention can achieve long-term pH stability. The corrosion rate comparison test subjects were Examples 1, 3, and 5 and Comparative Examples 1 and 6. The test method was the same as the material compatibility test of Example 1, with the immersion time extended to 60 days. The comparison indicators were the corrosion rate and appearance changes of each material (whether the glass coating layer peeled off, whether the plastic aged and discolored). The data were recorded and compiled into a comparison table according to sample type, material type, corrosion rate, and appearance evaluation (excellent / good / poor). The results showed that the corrosion rate of the glass coating layer of Examples 1, 3, and 5 was ≤0.01mm / year, and the plastic did not age and discolor. The corrosion rate of the glass coating layer of Comparative Example 1 (pH 8.5) was 0.03mm / year, and the PP plastic showed slight discoloration. The corrosion rate of the glass coating layer of Comparative Example 6 (pH 10.0) was 0.05mm / year, and the PC plastic showed obvious aging. This proves that the neutral formula and amino acid surfactant of this invention have excellent material compatibility. The cleaning efficiency comparison test subjects were Examples 2, 4, and 5 and Comparative Examples 3, 4, and 6. The test method was the same as the basic cleaning power test of Test Example 1, with the addition of cleaning time gradients (5 min, 10 min, and 15 min). The comparison indicators were the removal rate of tea stains, coffee stains, and milk stains under the same cleaning time and the shortest time required to reach a 90% removal rate. The data records were compiled into a comparison table according to sample type, stain type, cleaning time, removal rate, and shortest time to reach the standard. The results showed that the shortest time to reach a 90% removal rate for Examples 2, 4, and 5 was 5-8 min, while Comparative Example 3 (nonionic surfactant) required 12-15 min, Comparative Example 4 (without thickener) required 10-13 min, and Comparative Example 6 (alkaline formula) had a removal rate of only 75% (15 min) for milk stains. This proves that the combination of amino acid surfactant, thickener, and protease in this invention can significantly improve cleaning efficiency.The anti-fogging effect and residue comparison test subjects were Examples 3 and 5 and Comparative Example 5. The test method was to place the cleaned glass cup in an environment of 5℃ and 40℃ alternately, and observe the fogging time and fog dissipation time of the cup wall. At the same time, the cup was rinsed with deionized water 3 times after cleaning, and the rinse water was used to determine the anti-fogging agent residue using high performance liquid chromatography. The comparison indicators were fogging time (≥30s is better), fog dissipation time (≤10s is better), and residue (≤0.001mg / cm² is better). Data records were compiled into a comparison table according to sample type, fogging time, fog dissipation time, residue, and comprehensive evaluation (excellent / good / poor). The results showed that the fogging time of Examples 3 and 5 was ≥40s, the fog dissipation time was ≤8s, and the residue was ≤0.0008mg / cm². The fogging time of Comparative Example 5 (excessive antifogging agent) was 25s, the fog dissipation time was 15s, and the residue was 0.003mg / cm². This proves that the dosage limit of the antifogging agent of the present invention can take into account both antifogging effect and no residue. The enzyme activity retention rate comparison test subjects were Examples 2 and 5 and the blank group without buffer pair (based on Example 2, the sodium citrate-citric acid buffer pair was removed). The test method was to determine the neutral protease activity after storage at 40℃ for 1, 3, 6, and 12 months using the Folin-phenol method, and calculate the enzyme activity retention rate. The comparison index was the enzyme activity retention rate at different storage times and whether it met the requirement of ≥85% (6 months). The data records were compiled into a comparison table according to sample type, storage time, enzyme activity, and retention rate. The results showed that the enzyme activity retention rate of Examples 2 and 5 was ≥85% after 6 months of storage at 40℃ and still ≥75% after 12 months. The enzyme activity retention rate of the blank group was only 60% after 3 months of storage and dropped to 45% after 6 months. This proves that the sodium citrate-citric acid buffer pair of the present invention can effectively protect enzyme activity. As a comparison, Comparative Example 7, which used a phosphate buffer system, had an enzyme activity retention rate of only 62% under the same test conditions.

[0044] 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 pH-neutral amino acid surfactant-based water cup cleaner, characterized in that, The cleaning agent comprises the following components by weight percentage: 10-25% amino acid surfactant with a purity ≥98%, 1-5% sodium citrate-citric acid buffer pair, and 65-85% deionized water; The amino acid surfactant is selected from at least one of sodium cocoyl glutamate and sodium lauroyl sarcosinate; the weight ratio of sodium citrate-citric acid buffer pair to amino acid surfactant is 1:2-5; the pH value of the detergent is 6.5-7.

5.

2. The pH-neutral amino acid surfactant-based water cup cleaner according to claim 1, characterized in that, It also includes 0.1-0.5% neutral protease, which is Bacillus subtilis neutral protease with an enzyme activity ≥5000U / g and a pH range of 6.0-8.0; The weight ratio of neutral protease to amino acid surfactant is 1:20-50.

3. The pH-neutral amino acid surfactant-based water cup cleaner according to claim 1, characterized in that, It also includes 0.2-0.8% plant-derived anti-fogging agents; Plant-derived anti-fogging agents are sucrose fatty acid esters with an HLB value of 8-10. The weight ratio of sucrose fatty acid ester to sodium citrate is 1:4-8.

4. The pH-neutral amino acid surfactant-based water cup cleaner according to claim 3, characterized in that, It also includes 0.3-1.0% of a biodegradable thickener, which is food-grade hydroxypropyl methylcellulose. The viscosity of the detergent at 25°C is... ; The weight ratio of hydroxypropyl methylcellulose to deionized water is 1:65-283; When plant-derived antifogging agents are also included, the weight ratio of hydroxypropyl methylcellulose to plant-derived antifogging agents is 1:0.2-2.

7.

5. The pH-neutral amino acid surfactant-based water cup cleaner according to claim 1, characterized in that, The amino acid surfactant is a compound of sodium cocoyl glutamate and sodium lauroyl sarcosinate in a weight ratio of 1:0.5-2. The surface tension after compounding is ≤30mN / m, and the test condition is 25℃.

6. A pH-neutral amino acid surfactant-based water cup cleaner according to claim 1, characterized in that, The deionized water has a conductivity of ≤20μS / cm, the detergent has a pH fluctuation of ≤0.1 after being stored at 0-40℃ for 6 months, and the amino acid surfactant has a hydrolysis rate of ≤2% / year.

7. A pH-neutral amino acid surfactant-based water cup cleaner according to claim 2, characterized in that, The sodium citrate-citric acid buffer pair ensures that the neutral protease retains ≥85% of its activity after being stored at 0-40°C for 6 months.

8. A pH-neutral amino acid surfactant-based water cup cleaner according to claim 3, characterized in that, The sucrose fatty acid ester forms a hydrophilic film on the glass or ceramic glaze, with a thickness of ≤0.5μm. The sucrose fatty acid ester spreads with the water flow during the cleaning and rinsing stage, and there is no visible residue after the film is formed.

9. A pH-neutral amino acid surfactant-based water cup cleaner according to claim 4, characterized in that, The cleaning agent has the following performance characteristics: it adheres to the inner wall of the water cup for up to 30 seconds, and removes coffee stains from the inner wall of the water cup by no less than 95% at 25°C.

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