WO2022082915A1 - High-concentration detergent and preparation method therefor - Google Patents

Abstract

A high-concentration detergent, comprising, in percentages by mass, the following components: 40-60% of sodium α-C_14-16alkenesulfonate, 5-15% of lauryl hydroxysulfobetaine, 2-8% of PEG-15 cocomethylammonium chloride, 5-15% of a solvent, and 12-18% of a chelating agent. Further provided is a method for preparing the high-concentration detergent. The high-concentration detergent can be directly adsorbed onto a toilet cleaning brush. When brushing and cleaning a toilet, an excellent amount of foam is immediately generated, and by utilizing the action of the foam on dirt and by means of the mechanism of penetration wetting, permeation, dissolution and emulsification actions, dirt adhered to the toilet is eliminated with a relatively high level of decontamination. The detergent has a concentration of up to 50% by weight or more, and the use amount for cleaning is only half or less of that of a common commercially available product of the same type.

Description

Highly concentrated cleaning agent and preparation method thereof

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application for invention with application number 202011134576.9 filed on October 21, 2020, the content of which is incorporated into this application by reference.

technical field

The invention relates to the technical field of cleaning agents, in particular to a highly concentrated cleaning agent and a preparation method thereof.

Background technique

The toilet is a must-have product for modern households. To maintain a bright and clean appearance of the toilet, it is necessary to do a good job of cleaning and maintenance. Otherwise, if it is not cleaned for a long time, the yellow stains cannot be separated from the toilet, resulting in smelly and laborious cleaning in the end. Unsightly, there will even be bursts of odor, affecting the mood and health of the toilet.

Toilet cleaners have long been based on strong acids or alkalis. When cleaning and using the product, you must wear gloves to prevent accidental contact with the cleaner, causing skin injuries or discomfort, and you need to buy a toilet brush and cleaner at the same time. Two products, used together, can clean the toilet. There are many cleaning tools and there are concerns about skin damage caused by strong acids and alkalis.

Generally, the concentration of commercially available toilet cleaners is generally controlled at 5-20% by weight (the amount of water is greater than 70% by weight), and the solid raw materials can be easily dissolved in water, but the highly concentrated formula has less water, and the solubility of the solid raw materials is reduced. The solubility becomes poor, the formula is unstable, and the production process is difficult, or the ingredients are not dissolved, re-precipitated, stratified, and turbid.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the shortcomings of the above-mentioned prior art, and provide a highly concentrated cleaning agent and a preparation method thereof, a weakly acidic safe cleaning formula, combined with new technology cleaning components, to achieve effective cleaning, antibacterial, deodorant and antifouling High efficiency, allowing cleaning and maintenance to be completed at one time, providing simple, labor-saving and time-saving toilet cleaning products.

In order to achieve the above object, the highly concentrated cleaning agent provided by the present invention has the following:

In mass percent, it includes the following components:

Preferably, the chelating agent includes citric acid, lactic acid, citrate, sulfate, phosphate, EDTA, disodium EDTA, tetrasodium EDTA, dimethyl carboxymethyl. One or more of tetrasodium glutamate and trisodium dicarboxymethylalanine.

Preferably, the chelating agent includes citric acid, tetrasodium dicarboxymethyl glutamate and sodium citrate.

Preferably, the solvent includes one or more of dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, diethylene glycol monobutyl ether, propylene glycol, and ethanol.

Preferably, the cleaning agent includes one or more antibacterial agents.

Preferably, the cleaning agent includes one or more of non-ionic surface active, essence, deodorant, foam stabilization, anti-dirt adhesion and easy-to-clean ingredients, preservatives, colorants or thickeners.

The present invention also provides a preparation method of the highly concentrated cleaning agent, the preparation method comprising the steps:

(1) the alkaline metal chelating agent is dissolved in pure water;

(2) add lauryl hydroxy sulfobetaine, stir;

(3) adding solvent, stirring;

(4) add PEG-15 cocoyl methyl ammonium chloride, stir;

(5) adding sodium α-C _14-16 olefin sulfonate, stirring to a completely transparent and clear state to obtain the highly concentrated cleaning agent of the present invention.

Preferably, in the step (2), the stirring speed is 15-25 rpm, and the stirring time is 4-6 min; in the step (3), the stirring speed is 15-25 rpm, and the stirring time is 4-6 min. In the described step (4), the stirring speed is 15～25rpm, and the stirring time is 8～12min; in the described step (5), the stirring speed is 25～35rpm, and the stirring time is 13～17min.

Preferably, between the steps (3) and (4), a step (3-1) is also included: adding a solid organic acid salt and an organic acid chelating agent, and stirring;

Also comprise steps between described steps (4) and (5):

(4-1) adding amphoteric acrylic polymer, stirring;

(4-2) Add antibacterial agent and preservative, and stir.

After the described step (5), it also includes the steps:

(6) add spice, stir;

(7) Add nonionic surfactant and stir uniformly for 10 minutes.

Preferably, in the step (3-1), the stirring speed is 15-25 rpm, and the stirring time is 18-22 min; in the step (4-1), the stirring speed is 15-25 rpm, and the stirring time is 8～12min; in the described step (4-2), the stirring speed is 15～25rpm, and the stirring time is 4～6min; the stirring speed in the described step (6) is 45～65rpm, and the stirring time is 18～65 rpm. 22min; in the step (7), the stirring speed is 25-35rpm, and the stirring time is 8-12min.

The highly concentrated cleaning agent of the present invention and the preparation method thereof can be directly adsorbed on the toilet cleaning brush, and when the toilet is brushed, excellent foam is immediately generated, and the effect of foam and dirt is used to penetrate through the mechanisms of wetting, penetration, dissolution and emulsification. , to remove the dirt attached to the toilet, and the decontamination is stronger; and the concentration of the cleaning agent of the present invention is as high as 50% by weight or more, and the cleaning dosage is only half or less of the same product on the market, that is, it has excellent cleaning performance. It can also reduce the amount of detergent packaging materials, and save the drying time of the composite production of detergents and toilet brushes, so as to achieve environmental protection, carbon reduction, energy saving and production efficiency.

Description of drawings

1 to 4 are respectively a comparison diagram of the decontamination effect of the fifth embodiment of the highly concentrated cleaning agent of the present invention.

Detailed ways

In order to describe the technical content of the present invention more clearly, further description will be given below with reference to specific embodiments.

In the selection of ingredients used in toilet cleaners, priority is given to ingredients that comply with international regulations and safety standards, including EU CosIng-Cosmetic, and the list of ingredients in the US CIR and mainland China's international cosmetic raw material standards. You can query the ingredients in Chinese and the corresponding international English names. , and the functional use and safety assessment data of the ingredients can be obtained. The antibacterial ingredients are approved for use in the US Environmental Protection Agency TSCA chemical list, and the ECHA European Chemicals Agency announces the use.

The highly concentrated cleaning agent provided by the present invention can be combined with toilet brush cleaning tools to exhibit cleaning agent performance, has excellent and long-lasting foam, and utilizes the synergistic effect of different components, the cleaning components stay and dirt to wet, penetrate, emulsify and clean and remove It can achieve excellent cleaning effect, making the bathroom and toilet environment safer, more convenient and more effective when cleaning.

The highly concentrated cleaning agent of the present invention can be attached to toilet cleaning brushes of different materials by a drying method.

The composition of the highly concentrated cleaning agent provided by the present invention includes:

anionic surfactant

Anionic surfactant cleaning ingredients include: sulfonates, sulfates, phosphates and carbonates, such as linear sodium dodecylbenzenesulfonate, sodium laureth sulfate, Sodium lauroyl sarcosinate, sodium xylene sulfonate, etc. are all within the scope of the present invention.

The toilet cleaning agent of the present invention can contain at least one alkyl sulfonate component, and the carbon number distribution C _14-18 sodium α-alkenyl sulfonate is the main choice, and the most preferred content is 40 to 60% by weight, Sodium alkene sulfonate with carbon number distribution of C _14-16 , with better solubility, wetting power, foaming and detergency.

amphoteric surfactant

General cleaning performance amphoteric surfactants include: alkylamine fatty acid salts, alkyl betaines, sulfobetaines, amine oxides with high wettability, etc., such as decylamine oxides, lauramidopropyl betaine, coconut Oleyl betaine, cocamidopropyl dimethylamine, sodium cocoamphoacetate, sodium lauroamphoacetate, etc. are all within the scope of the present invention. The test result of the present invention selects cocamidopropyl hydroxy sulfobetaine and lauryl hydroxy sulfobetaine, and is preferably selected for excellent foaming properties in hard or soft water, and is compatible with anions, non-ions and cations. Very good compatibility, can maintain isoelectric state in all pH value ranges, activity does not change with pH value, stable product quality, and contains 5 to 15% by weight of lauryl hydroxysulfobetaine.

Cationic Surfactant

General cationic surfactants include: ammonium salts, ether ammonium, quaternized polyoxyethylated long-chain amines, amine oxides, etc., such as PEG-15 coco methyl ammonium chloride, dialkyl dimethyl ammonium chloride Ammonium salts, alkyl trimethylammonium salts, etc. are all within the scope of the present invention. In the present invention, it is more preferable that the scale removal ability is strong, and it has chelating ability and antistatic function, and can be stably compounded with amphoteric surfactants, nonionic surfactants and anionic surfactants, and the content is 2 to 8% by weight of PEG-15 Coco Methyl Ammonium Chloride improves cleaning performance and prevents redeposition of dirt during cleaning.

nonionic surfactant

Improve the cleaning and decontamination ability of the product, and add non-ionic surfactants with excellent penetration performance and oily emulsification performance, including: polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, alkyl glycoside, etc. The research results are preferably based on polyoxyethylene alkyl ethers, alkyl glycosides, and oleylamine ethoxylates, such as PPG-9-ethylhexanol polyether-5, C _9-11 alkanol polyether- 3. Ethoxylated C _12-14 -alcohols, alkyl polyglucosides, etc. are all within the scope of the present invention. The present invention does not use nonylphenol non-ionic interfacial activity that is unfriendly to the ecological environment, and more preferably biodegradable at least one kind of PPG-9-ethylhexanol polyether-5 and ethoxylated C _12-14 - Alcohol, adding a small amount can reach the critical micelle concentration CMC structure, reduce surface tension, and have excellent wetting, rapid dissolving and cleaning capabilities, and the final preferred content of 1 to 5% by weight PPG-9-ethylhexanol polyether- 5.

solvent

To clean the hard surface of toilet ceramics, select organic solvents, especially organic solvents containing oxygen atoms, which have the characteristics of high solubility and low toxicity, including alcohols, carboxylic acids, esters, glycols, glycol ethers and ketones, all of which have excellent solubility It can enhance the synergistic effect of ingredients such as anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants. Alcohols are preferred in toilet cleaner formulations. Ether and alcohol solvents, including: Dipropylene Glycol n-Propyl Ether, Dipropylene Glycol n-Butyl Ether, such as DOWANOL series PnP, DPnP, PnB, DPnB, Hexyl CELLOSOLVE solvent, Hexyl CARBITOL solvent, Butyl CARBITOL solvent, Propylene Glycol Propylene Glycol , Ethanol, etc. are all within the scope of the present invention. The present invention more preferably includes monoethers that conform to the production process with good hydrophilicity, low viscosity, excellent solubility, and have a coupling function to effectively improve the composite function of components in the formula: diethylene glycol monobutyl ether, with a content of 5 to 15 weight%.

chelating agent

The dirt in the toilet includes urine scale, scale and excrement adhesion. The dirt components are mainly inorganic salts such as calcium oxalate, calcium phosphate, calcium carbonate, etc. The characteristics of chelating agents can be used to effectively improve the inorganic salts on hard surfaces. Soil-like dissolving and removing effect. Ingredients include: maleic acid, citric acid, succinic acid, sulfonic acid, phosphoric acid, salicylic acid, sorbic acid, sulfamic acid, acetic acid, caproic acid, oxalic acid, lactic acid, citrate, sulfate, phosphate, 2- Methyl 2,4-pentanediol 2-Methyl-2,4-pentanediol, Trisodium Dicarboxymethyl Alanine, EDTA, Tetrasodium EDTA, Dicarboxymethyl Glutamine Tetrasodium dicarboxymethylalanine, trisodium dicarboxymethylalanine, etc. In the present invention, the combination of citric acid, lactic acid, sodium citrate and tetrasodium dicarboxymethylglutamate is preferred, and the most preferred content is 12 to 18% by weight of a chelating agent.

Anti-fouling and easy-to-clean ingredients

Improve the easy cleaning and anti-fouling performance of the cleaner. The formula contains compound ingredients such as acrylic polymer Acrylic Co-Polymer, fatty alcohol polyoxyethylene ether and nano-silica, which can form a protective film on the surface of the toilet, making it difficult to get dirty. Adhesion, and the dirt in the cleaning process will not return to the dirt, maintaining the cleanliness of the toilet.

Antibacterial agents

To keep the toilet clean and hygienic, the present invention contains at least one or more antibacterial ingredients, including: quaternary ammonium salt compounds such as didecyl/dioctyldimethylammonium chloride, benzalkonium chloride, alkyl (C12 -18) Benzyl dimethyl chloride, n-alkyl (C12-18) dimethyl benzyl ammonium chloride, alkyl (C12-14) dimethyl ethyl benzyl ammonium chloride (average Molecular weight: 377-384), n-alkyl (C12-18) dimethyl ethyl benzyl ammonium chloride (average molecular weight: 384), di-n-alkyl (C8-10) dimethyl ammonium chloride (average molecular weight: 384) Molecular weight: 332-361), Didecyldimethylammonium carbonate/Didecyldimethylammonium bicarbonate, 2-phenyl-phenol, ethanol, hydroxydichlorodiphenyl ether, polyaminopropyl biguanide, silver ion , hypochlorous acid, hydrogen peroxide, etc. The preferred antibacterial ingredients are didecyl/dioctyldimethyl ammonium chloride, benzalkonium chloride, bisdecyl dimethyl ammonium chloride, bis-decyl dimethyl ammonium chloride, octyl decyl dimethyl ammonium chloride Ammonium chloride, methylchloroisothiazolinone and methylisothiazolinone form an excellent antibacterial effect.

essence

It preferably contains citrus, fruity, grassy, jasmine, orange blossom, ylang-ylang, rose, violet, geranium, eucalyptus, lavender, patchouli, sandalwood, musk, aldehyde, powder, cedar, etc. The fragrance is mixed, and FRESHPLEX ^TM , a patented deodorant ingredient of Mansfield fragrances, can be added to remove common odor sources in toilets. In order to reduce the production and the toilet brush material combined with the adhesion process, reduce the volatilization of the aroma, the aroma is preferably mainly composed of floral and fruity and woody notes, improve the temperature stability and retain the aroma after processing, and then use the detergent to dissolve in water when cleaning the toilet. When it is released again, the aroma evaporates.

Based on the above components, the cleaning agent of the present invention has five-in-one functions of cleaning, antibacterial, deodorizing, anti-pollution and pleasant fragrance, and combined with cleaning brushes, solves the tedious toilet cleaning work.

The present invention also provides a preparation method of the highly concentrated cleaning agent:

(1) The alkaline metal ion chelating agent is dissolved in pure water;

(2) adding lauryl hydroxy sulfobetaine, rotating speed 20rpm, uniformly stirring for 5 minutes;

(3) adding diethylene glycol monobutyl ether, rotating speed 25rpm, uniformly stirring for 5 minutes;

(3-1) Add solid organic acid salt and organic acid chelating agent, rotate speed 30rpm, stir evenly for 30 minutes;

(4) add PEG-15 cocoyl methyl ammonium chloride, rotating speed 25rpm, uniformly stir 10 minutes;

(4-1) Add amphoteric acrylic polymer, rotate speed 25rpm, uniformly stir for 10 minutes;

(4-2) Add cationic antibacterial agents and preservatives, rotate at 25 rpm, and stir evenly for 5 minutes;

(5) adding anionic surfactant α-C14-16 sodium olefin sulfonate, rotating speed 30rpm, after uniform stirring for 15 minutes, check that all components are completely dissolved and are in a completely transparent and clear state;

(6) increase the rotating speed to 50rpm, add the spice ingredients, and stir evenly for 20 minutes;

(7) The rotation speed is reduced to 30rpm, the nonionic surfactant PPG-9-ethylhexanol polyether-5 is added, and the mixture is uniformly stirred for 10 minutes;

(8) Stop testing the product transparency, pH value, specific gravity and solid weight %.

The following detailed description of example formulations illustrating certain preferred embodiments of the detergent compositions of the present invention is not intended to limit the scope of the present invention.

The cleaning agent of the present invention must be able to produce excellent foaming properties after being combined with the toilet brush, and can still exhibit excellent foaming power during the cleaning process of dirt, and the cleaning effect can be improved through the increase of foam persistence and the time of dirt action. Therefore, Foam height and foam stability are the key requirements for formulation invention.

Description of foaming force test method:

Although the initial height of foam is not directly related to the cleaning power, when it encounters pollutants, the degree of foaming will be affected, which means that the cleaning ability of pollutants will be affected and reduced. The foaming power performance and the decline range of the material were used to determine the cleaning power of the formula.

The dirt represents that the main dirt of the toilet is inorganic salts such as urine scale and scale and general dirt. The dirt components of the following test mixture are composed of calcium carbonate, calcium sulfate, magnesium sulfate, soybean oil, soy sauce, and flour.

Foaming power test method: The foaming machine MIXER device used to test the foaming power with surface activity, stir at a constant speed for 5 seconds, the aqueous solution is 1%, and record the foam height for 1 minute, 10 minutes, and 20 minutes.

After the high-concentrate cleaning solution of the present invention is diluted 3 times, the foaming degree at 1% by weight and the degree of foaming power in a dirty environment are compared with the common detergent products in the market, and the cleaning power is compared.

The highly concentrated toilet bowl cleaner of the present invention contains the following combination components:

The pH value of all the examples at 25°C is controlled to be 4±0.2, which is different from the common toilet cleaner products whose pH value is less than or equal to 2, which will irritate and damage the skin when contacted.

According to the formula combination and the preparation operation procedure of the present invention, the test results show that the optimal ratio and the production operation conditions must be as follows: the water, the chelating agent, the amphoteric surfactant and the solvent are first stirred uniformly, and then the organic citric acid and citrate are added. The chelating agent should be slowly stirred until dissolved before adding other ingredients. The essence is oil-soluble to avoid product turbidity. After feeding, the shear force should be increased to 50-60 rpm. The non-ionic surfactant PPG-9- Ethylhexanol polyether-5 has an emulsifying function and is added after the essence is fed to improve product stability.

Foaming power test: The foaming power of the product of Example 5 is compared with the foaming power test table of commercially available toilet cleaners:

Example 5 The foaming power is 197.5mm higher than the commercial toilet cleaner in 1 minute, which is 239% higher, and the foaming power is 115mm higher after 20 minutes, which is 209% higher; 1 minute in a dirty environment When the foaming power is higher than 132.5mm, it is 539% higher. After 20 minutes, the foaming power is higher than 67.5mm, which is 386% higher. The foaming power is obviously better than that of the commercially available products.

In Example 5, the foaming power decreased less than that of commercially available toilet cleaners in a dirty environment, indicating that the cleaning power was stronger for dirt and less affected by dirt.

Description of soil removal test method:

Simulate urine scale and limescale components attached to the surface of the tile, and test the removal efficiency of concentrated cleaners.

Dirt production: use a filter screen to quantify 0.3 grams of calcium carbonate, calcium sulfate, magnesium sulfate, table salt and 6000 mesh bamboo charcoal powder, evenly spray it on the surface of an 80.85cm2 tile, and then spray water to solidify the dirt, then place it on the surface of the tile. Bake in a 50°C oven for 60 minutes, take it out, and place it at room temperature to warm up for later use.

The composition of the fixed cleaning agent is 1% by weight dilution, stir at a constant speed for 5 seconds with the foaming machine MIXER device, take 3 grams of foam after beating into foam, evenly spread it on the 80.85cm2 dirty area, and place the tiles at an angle of 17.5° Corner, let sit for 15 minutes to allow the foam to interact with the stain on the tile.

After 15 minutes, rinse with 3 mL of tap water, and rinse the dirty area twice for a total of 2 times, and then the professional product development researcher will evaluate the dirty cleaning effect.

Dirt adhering to the tile dirt removal effect test:

Example 5 Comparison of the cleaning power of the toilet bowl cleaner and the commercially available toilet bowl cleaner for removing dirt:

As shown in Figure 1, the three areas from left to right are not added with cleaning agent; as shown in Figure 2, the cleaning agents of Example 5, commercially available product 1, and commercially available product 2 are added sequentially from left to right; as shown in the figure 3, the three areas after the first cleaning; as shown in Figure 4, the three areas after the second cleaning. Under the same weak acid products, compared with the commercial product 2 in Example 5, after the first and second rinsing, the decontamination effect is better than that of the commercial product 2.

Compared with the strong acid product of the commercial product 1, the decontamination effect of Example 5 is also better than that of the commercial product 1 after the first and second rinsing. Better decontamination effect than strong acid products.

As a result, it was found that the concentrated toilet cleaning solution of the present invention has better foaming properties than commercially available toilet cleaning products, and also has better cleaning effect on dirt and dirt components than commercially available toilet cleaning products.

The highly concentrated cleaning agent provided by the present invention maintains the pH value at a weak acid level, provides a weak acid formula that is environmentally friendly, energy saving, carbon reduction, safe and effective cleaning, and is more secure than the general commercial toilet cleaner products using strong acid or strong alkali, and To achieve cleaning, maintenance, antibacterial, deodorization and air aroma to complete the toilet cleaning work at one time.

In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be evident that various modifications and changes can still be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Claims (10)

A highly concentrated cleaning agent is characterized in that, in terms of mass percentage, it comprises the following components:

The highly concentrated cleaning agent according to claim 1, wherein the chelating agent comprises citric acid, lactic acid, citrate, sulfate, phosphate, EDTA, disodium EDTA , one or more of tetrasodium EDTA, tetrasodium dicarboxymethyl glutamate and trisodium dicarboxymethyl alanine. The highly concentrated cleaning agent according to claim 1, wherein the chelating agent comprises citric acid, tetrasodium dicarboxymethyl glutamate and sodium citrate. The highly concentrated cleaning agent according to claim 1, wherein the solvent comprises one or more of dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, diethylene glycol monobutyl ether, propylene glycol and ethanol kind. The highly concentrated cleaning agent of claim 1, wherein the cleaning agent comprises one or more antibacterial agents. The highly concentrated cleaning agent according to claim 1, characterized in that, the cleaning agent comprises nonionic surface activity, essence, antibacterial agent, deodorant, foam stabilization, anti-dirt adhesion and easy-to-clean ingredients, preservatives, One or more of colorants or thickeners. A preparation method of the highly concentrated cleaning agent according to claim 1, wherein the preparation method comprises the steps: (1) the alkaline metal chelating agent is dissolved in pure water; (2) add lauryl hydroxy sulfobetaine, stir; (3) adding solvent, stirring; (4) add PEG-15 cocoyl methyl ammonium chloride, stir; (5) adding sodium α-C _14-16 olefin sulfonate, stirring to a completely transparent and clear state to obtain the highly concentrated cleaning agent of the present invention. The method for preparing a highly concentrated cleaning agent according to claim 7, wherein in the step (2), the stirring speed is 15-25 rpm, and the stirring time is 4-6 min; in the step (3) , the stirring speed is 15～25rpm, and the stirring time is 4～6min; in the described step (4), the stirring speed is 15～25rpm, and the stirring time is 8～12min; in the described step (5), the stirring The rotating speed is 25～35rpm, and the stirring time is 13～17min. The preparation method of highly concentrated cleaning agent according to claim 7, is characterized in that, between described steps (3) and (4), also comprises step (3-1): adding solid organic acid salt and organic acid chelating agent, stirring; Also comprise steps between described steps (4) and (5): (4-1) adding amphoteric acrylic polymer, stirring; (4-2) Add antibacterial agent and preservative, and stir. After the described step (5), it also includes the steps: (6) add spice, stir; (7) Add nonionic surfactant and stir uniformly for 10 minutes. The method for preparing a highly concentrated cleaning agent according to claim 9, wherein in the step (3-1), the stirring speed is 15-25 rpm, and the stirring time is 18-22 min; the step (4-1) The rotating speed of stirring in -1) is 15～25rpm, and the stirring time is 8～12min; the rotating speed of stirring in the described step (4-2) is 15～25rpm, and the stirring time is 4～6min; the step (6) ), the rotating speed of stirring is 45～65rpm, and the stirring time is 18～22min; the rotating speed of stirring in the step (7) is 25～35rpm, and the stirring time is 8～12min.

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