Metal cleaning agent development method

Development method of metal cleaning agent Whether it is in the laboratory of the research department or the laboratory of the enterprise, the development and development of metal cleaning agent is generally carried out according to the following steps.

Clarify the cleaning object, requirements and dosage form.

Find relevant materials and patents, and conduct market research if necessary.

Master the cleaning process and build a laboratory performance evaluation method.

Determine the basic components and, if necessary, dissect the sample for reference.

Conduct a formula screening test to establish a basic formula.

Conduct field application tests to validate the base formula and identify problems and deficiencies.

Refine the formulation and finalize it, focusing on the performance/price ratio.

Measure the performance index, conduct the test of the use conditions, and clarify the precautions in use.

Perform scale-up tests for field applications.

Drafting of corporate standards.

Promote the application of products, test marketing products and do a good job in technical services.

Conduct new product appraisal and meet sales conditions.

1. Water-based metal cleaning agent In the process of metal processing, metal cleaning objects are divided into two categories, one is rust removal and the other is oil removal. The cleaning agents for cleaning oil stains on metal surfaces can be divided into three categories: the first type is solvent-based cleaning agents, the main components are organic solvents such as gasoline, kerosene or halogenated hydrocarbons; The second type is water-based cleaning agents, which are mainly composed of surfactants, additives, etc.; The third type is a composite cleaning agent, which is mainly composed of surfactants, organic solvents, additives, etc. Current metal cleaners are usually referred to as water-based metal cleaners.

(1) Requirements to be met by metal cleaning agents

It has good surface activities such as wetting, solubilization and emulsification, strong degreasing ability, and there is no visible oil film or oil spot on the surface of the workpiece after cleaning.

There is no corrosion to metal materials, and the surface of the workpiece maintains the original luster of the metal after cleaning.

There is a certain anti-rust ability for metal materials, and after the metal or workpiece is cleaned, there will be no rust spots when the supply and demand are transmitted in the processing process, and there is no need for any anti-rust treatment.

The process performance is good, such as easy operation, low use temperature, easy to wash clean, no pollution of the environment or convenient treatment of three wastes.

(2) Consideration of components in the formulation of metal cleaning agents

Surfactants Since the cleaning object is mainly dirt, the selected surfactant should contain hydrophobic groups similar to the molecular structure of oil stains. The main components of oil stains are generally mineral oil and animal and vegetable oils, so the surfactants used for metal cleaning agents are usually aliphatic derivatives or aromatic derivatives with aliphatic hydrocarbons, and their HLB values are generally selected between 8 and 16. There are many raw materials for the preparation of metal cleaning agents, and surfactants with strong wetting, solubilization and emulsification abilities to oil stains are generally selected. Factors such as comprehensive resources and costs, such as triethanolamine oleate, alkyl phosphate, phenol ether or alcohol ether phosphate, fatty alcohol ethoxylate, etc. As with most detergents, a single surfactant is not as effective in a formulation as a combination of multiple surfactants, so metal detergents often contain more than two surfactants.

Alkali and alkaline salts Alkali and alkaline salts are also a type of cleaning agent, which is widely used in metal cleaning and can also be used as additives in surfactants. They are effective in cleaning animal and vegetable fats, fatty acid dirt and hydrophilic dirt, and can even react with grease and fatty acid dirt to form surface-active soap. When alkali is used alone, the decontamination ability is limited, but the cleaning ability can be improved by adding surfactants. Alkaline and alkaline salts have a corrosive effect on some metals, so alkaline cleaning agents cannot be used when cleaning metal parts with high quality requirements. Commonly used alkali and alkaline salts are caustic soda, sodium carbonate, sodium bicarbonate, sodium orthosilicate, sodium metasilicate, sodium orthophosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, etc.

Anti-rust and corrosion inhibitor The metal cleaning agent should contain a certain amount of anti-rust and corrosion inhibitor to meet the requirements of no corrosion and no damage to the metal surface during cleaning, and the metal surface is clean and bright after cleaning, and has a certain degree of corrosion and rust prevention. The main corrosion inhibitors added to water-based metal cleaning agents are corrosion inhibitors that control the corrosion rate, and there are two types: inorganic and organic. Rust inhibitors are oil-based additives used to prevent rust caused by atmospheric corrosion, and when used in aqueous metal cleaners, they can be dispersed in an aqueous solution by surfactants. The inorganic corrosion inhibitors used are sodium nitrite, sodium nitrite + anhydrous sodium carbonate, trisodium phosphate, disodium hydrogen phosphate, sodium tripolyphosphate, sodium silicate, potassium dichromate, ammonium carbonate, etc.; Organic corrosion inhibitors include sodium benzoate, ammonium benzoate, triethanolamine, ethanolamine, phenyethanolamine, metropine, urea, benzotriazole, etc. The compound use of corrosion inhibitors has a better effect, such as sodium nitrite + triethanolamine, sodium silicate + sodium tripolyphosphate, which have good anti-rust effects. For different cleaning objects, it is best to determine by experimentation.

Defoamers When metal cleaning agents are used, they are generally required to be cleaned in a low-foaming or non-foaming state. Too much foam can make mechanized or continuous cleaning impossible, especially if high-pressure spray cleaning requires the use of non-foaming or low-foaming cleaning agents. Therefore, metal cleaners need to add a certain amount of defoamer. Commonly used and representative defoamers include polyether 2010, polyether L61, tributyl phosphate, silicone, oleic acid, sodium oleate, etc. Some defoamers have a synergistic effect on the degreasing ability of metal cleaners, while others have a negative effect, so when screening defoamer varieties, they should be combined with other components to determine the selection and then perform a degreasing test, and then determine the formulation.

(3) Establish a method for measuring the cleaning effect An important task in the development of metal cleaning agents is to establish an evaluation method for the composition of the cleaning agent and the performance of some formulations according to its own conditions. Refer to the industry standard ZBY43003 - 1986 "Test Method for General Water-based Metal Detergents".

Preparation of metal specimens The specimens include steel, cast iron, brass, aluminum, stainless steel, etc., and the specifications and sizes are specified. Take the 45-gauge steel sheet as an example, the size is 50mm×50mm× (3 - 5) mm. Spread the No. 240 abrasive cloth on the flat plate, polish the specimen brightly, and the grinding direction is parallel to the long side of the specimen. After grinding, the specimen is first wiped with absorbent cotton, hung on an S-shaped hook, immersed in absolute ethanol, and then scrubbed with tweezers clamping absorbent cotton. The specimen is then rinsed in acetone, dried by hot air, and stored in a desiccator for later use.

Preparation of test solution For the test solution used in corrosive, rust resistance, rinsing and PH value test, distilled water or deionized water is prepared at 3%; For the test solution used in the test of cleaning power, foam and other tests, it is prepared with 250mg/kg hard water at 3%.

Determination of cleaning power The cleaning power is measured by a pendulum washing machine, and the oscillating frequency of the pendulum washing machine is specified to be (40±2) times/minute, and the swing distance is (50±2) mm.

Preparation of artificial oil stain Artificial oil stain formula: barium petroleum sulfonate 8%, lanolin magnesium soap 3.5%, lanolin 2%, industrial petrolatum 30%, No. 20 engine oil 34.5%, No. 30 engine oil 12%, calcium-based grease 2%, aluminum oxide 8%. Preparation method: According to the formula, mix and heat industrial petroleum jelly, No. 20 engine oil and No. 30 engine oil to about 20 degrees to dissolve evenly, pour lanolin magnesium soap, barium petroleum sulfonate, calcium-based grease and lanolin, stir and dissolve. Control the temperature not to exceed 130 degrees, after all are dissolved, stop heating, add alumina powder and stir evenly, and cool to room temperature.

Coating of artificial oil stains The prepared steel test piece is hung with a hook and dried in an oven at about 40 degrees Celsius for 30 minutes, with an accuracy of 0.2mg. Place the weighed specimen flat on a clean filter paper, use a small spatula to ingest the artificial oil stain, evenly coat it on the specified part of one side of the specimen, and wipe off the excess oil stain on both sides and bottom edge of the specimen with filter paper. The amount of oil coating is controlled between 0.08 - 0.19g. Then hang the coated test piece with a hook, put it in a 40-degree oven to dry for 30 minutes, then take it out, wipe off the oil stain on the bottom edge with filter paper, and weigh it after cooling.

Test procedure Pour 400ml of detergent solution into a 500ml beaker, and then place the beaker in the water bath hole of the pendulum washing machine to keep the temperature of the detergent solution around 60 degrees. The coated specimen is clamped on the pendulum frame of the pendulum washing machine, so that the surface of the specimen is perpendicular to the direction of swing. Soak in the detergent solution for 3 minutes, and then turn on the pendulum washing machine to wash for 3 minutes. After the washing is completed, take out the test piece together with the hook, wash it in 400ml of distilled water at about 60 degrees for 30 seconds, remove the test piece, and dry it in an incubator at about 40 degrees for 2 hours. After cooling to room temperature, weigh and calculate the net washing power.

Calculation of net washing power % Net washing power % = (mass of the specimen after coating with oil - mass after cleaning) / (mass of the specimen after coating with oil - mass of the specimen)

Result evaluation Parallel test with three test pieces, of which at least two pieces of the value difference is not more than 3%, otherwise the test should be re-tested. The average value was taken as the measurement result. According to the standard requirements, the net washing power of the product should be greater than or equal to 90%.

Corrosivity test The metal test is immersed in a cleaning solution at a certain temperature, and after a specified period of time, the corrosivity of the cleaning agent to the metal is evaluated by the appearance and quality changes of the metal test piece.

Test procedure Put the enamel drug tank containing 400ml of test solution into a constant temperature water bath, so that the test solution has a constant temperature of 80 degrees. The specimen (with hook) is dried in a 40-degree oven for 30 minutes, cooled and weighed. Then hang it on the beam that is placed horizontally on the mouth of the drug cylinder, so that the test piece is completely immersed in the test solution (no bottom, no face). Only two test pieces of the same material are placed in each tank, and after 2 hours, the test pieces are taken out, rinsed with freshly boiled cold distilled water (10 times), dehydrated with acetone and dried with hot air, and the appearance is checked. Then the test piece (with hook) is placed in an oven at about 40 degrees Celsius to dry for 30 minutes, and after cooling, it is weighed, and the mass change is calculated as the amount of corrosion, which is expressed in mg. Amount of corrosion = before cleaning - after cleaning.

Result assessment grade 0: no rust on the surface, no obvious change; Grade 1: No rust on the surface, slight discoloration or loss of gloss; Grade 2: light rust on the surface, or uneven discoloration; Grade 3: Large area of rust on the surface. According to the standard requirements, for No. 45 steel, the appearance should be grade 0; The amount of corrosion should be less than or equal to 2mg.

Anti-rust test Put the drug tank containing 400ml of test solution into a constant temperature water bath at about 80 degrees, and soak the prepared test piece into the test solution for 30 seconds before taking it out. Absorb the liquid at the lower end of the test piece and the hole with filter paper, hang it vertically on the test piece holder, dry the test piece together with the rack in a 40-degree oven for 15 minutes, move the test piece holder into a humid heater that has been placed in the oven in advance at a constant temperature of about 35 degrees and a relative humidity of 90%, place it for 24 hours, keep the temperature at 35 degrees, and take out the test piece to check the appearance after the time is up. The rating method is the same as the corrosivity assessment. According to the standard requirements, the appearance of No. 45 steel is grade 0.

Other performance tests Foam performance test: The determination of foam is the same as that of laundry detergent, and it is measured with a Roche foam meter. According to the standard requirements, the metal cleaning agent requires low foam, that is, about 50 degrees, and the instant foam is less than or equal to 80mm; 5 minutes of foam less than or equal to 20mm. High and low temperature stability test: The product should meet the requirements of high and low temperature stability. High temperature test: pour the detergent into the graduated cylinder to the 50ml scale, put it into a 60 degree constant temperature water bath after plugging, the water surface should be 20mm higher than the scale, and take it out after 6 hours. After returning to room temperature, observe the appearance change, which should be uniform and not layered. Low temperature test: Put the sample that has not changed after the high temperature test (if the oil changes, change the sample) into the refrigerator at about minus 5 degrees Celsius and keep it for 24 hours. After taking out, it should be naturally restored to room temperature, and the appearance change should be observed, which should be uniform, not stratified, and no crystalline precipitation and precipitation. Determination of water volatiles: Weigh about 2 grams of detergent sample in a weighing dish with constant weight and weigh it to 0.2 mg. Dry in an oven at about 105 degrees for 4 hours, take it out and put it in a dryer to cool to room temperature, cover and weigh. The percentage of moisture and volatile content is calculated as follows: % of moisture and volatile content = weight loss of sample / 100% ×of sample mass. The difference between the two parallel test values should be less than 0.5%, and the average value of the two tests should be taken as the measurement results. According to the requirements of the standard, the moisture and volatiles of metal cleaning agents and liquid products should be less than or equal to 80%; The slurry should be less than or equal to 50%; The powder should be less than or equal to 30%. Rinsing performance test: Put the beaker containing 400ml of test solution into a constant temperature water bath of about 60 degrees, hang the prepared test piece on the S-shaped hook, immerse it in the test solution for 5 minutes, immediately use filter paper to absorb the liquid at the lower end of the test piece and the eyelet, hang it vertically on the test piece rack, put it into an oven of about 40 degrees to dry for 30 minutes, take out the test piece and swing back and forth 10 times (1 time for round trip) in 400ml and about 60 degrees of distilled water, and the pendulum washing time does not exceed 10 seconds. After taking it out, dry it with hot air to check the appearance of the specimen, and use two specimens for parallel testing at the same time. The result evaluation is to check whether there is any detergent residue on the surface of the test piece. PH DETERMINATION OF 3% SAMPLE SOLUTION WITH A PH METER CAN GENERALLY BE DETERMINED BY PH PAPER. According to the requirements of the standard, the PH value of detergents for steel and cast iron is required to be greater than 7; Detergents for copper and copper alloys, aluminum and aluminum alloys require a pH value between 7 and 11.5.

Screening of metal cleaner formulations

Surfactants The cleaning effect of various surfactants is related to the type of object to be washed, the nature of the dirt and the temperature. For example, if carbon black and mineral oil are applied to a steel surface in a 1:2 mass ratio, the cleaning effect of the various surfactants under the same conditions is in the following order: nonionic surfactant> cationic surfactant = alkyl sulfate > soap. The following issues should be paid attention to when choosing surfactants: Nonionic surfactants and anionic surfactants are more widely used in metal cleaning agents, and the combination of the two can produce a good synergistic effect, and its emulsification, solubilization, dispersion and cleaning effects will be enhanced. Attention should be paid to the HLB value, taking into account the ability of the metal cleaner to reel and disperse the dirt, and the HLB value of the surfactant used is generally 8 - 16. Most molecular ion surfactants have a cloud point, as a surfactant for metal cleaning agents, its cloud point should not be too low, generally higher than the use temperature of the cleaning agent, otherwise there will be turbidity in the cleaning process, reduce its surface activity, but the cloud point does not have to be too high, the increase in HLB value will make the surfactant hydrophobic group too weak, which is not conducive to oil cleaning. In water-based metal cleaning agents, the cleaning power and rust resistance of surfactants are often contradictory and mutually inhibitive. The main function of cleaning is to remove the oil from the metal surface and prevent re-deposition on the metal surface; The anti-rust mechanism is mainly to strengthen the adsorption effect and form a dense adsorption film on the metal surface to isolate all corrosive media. Despite this, there are fatty acids such as alkanolamide and polyoxyethylene aliphatic amine that have both decontamination and rust prevention functions, and can be used for anti-rust metal cleaning agents. Effect of soft and hard water on the net washing power of surfactants: nonionic surfactants have strong resistance to hard water and are generally not affected by the hardness of water, but the water hardness has a great influence on the net washing power of anionic surfactants. For example, sodium alkylbenzene sulfonate has a net washing power of 77.4 in soft water and only 19.4 in hard water. Effect of temperature on the cleaning power of surfactants: Nonionic surfactants are basically not affected by temperature, but when the temperature exceeds the cloud point, the cleaning power will decrease. However, there is an effect on the temperature of anionic surfactants or cleaning agents where anionic surfactants and nonionic surfactants are compounded. For example, the net washing power of the cleaning agent compounded with anionic surfactant and nonionic surfactant in distilled water is 32.87 at 15 degrees, 77.99 at 45 degrees, and 88.95 at 80 degrees, and the cleaning power increases with the increase of temperature.

The properties of alkali and various alkaline salts are as follows:

The properties of alkali and various alkaline salts are as follows:

When choosing alkaline salts, it is important to pay attention to their different characteristics. For example, sodium carbonate in hard water produces insoluble calcium carbonate; The reaction of sodium bicarbonate with calcium ions will produce soluble calcium bicarbonate, which has a certain softening ability for hard water. Silicates have good hard water resistance and dirt dispersion ability, and have the effect of preventing dirt from re-adhesion; Sodium metasilicate has an inhibitory effect on the corrosion of non-ferrous metals such as aluminum, zinc and tin. Polyphosphate has low alkalinity, can soften hard water, strong dispersion power, can prevent metal corrosion, also has the effect of preventing dirt adhesion, and surfactant compound can increase cleaning power, is an excellent detergent.

Compounding of various surfactants: Surfactants AEO-9 (primary), AEO-9 (secondary), AEO-7, AES, TX-10, LAS-Na, etc. are used for compounding.

All compounds of LAS-Na have poor cleaning power, and the higher its content, the worse the cleaning power. The nonionic surfactant compound works well.

Surfactant and alkaline salt compounding:

In the case of alkali 3%, surfactant 1%, water 96%, alkali 4% and water without surfactant, surfactant and alkaline salt compound can significantly improve the cleaning power. Some surfactants are selective to alkaline substances, for example, after LAS-Na is mixed with various alkaline substances, the cleaning power is improved to a certain extent, and the cleaning power is improved best when sodium orthosilicate is added; The selectivity of some surfactants is not obvious, for example, after TX-10 is mixed with alkaline substance, the net cleaning power can reach more than 95%, which is greatly improved.

Addition of anticorrosive corrosion inhibitors and other additives: In the cleaning agent of iron and steel parts, sodium nitrite, sodium carbonate, organic ammonium, sodium benzoate, triethanolamine oleate, alkyl alcoholamide, etc. can be added as corrosion inhibitors; Benzotriazole and its derivatives can be added as corrosion inhibitors in copper parts cleaning agents; Sodium silicate, potassium silicate, etc. can be used as corrosion inhibitors for aluminum parts cleaning agents; Silicates are also inexpensive corrosion inhibitors for steel parts in aqueous neutral solutions. A new type of surfactant, cationic imidazoline, has a good effect as a corrosion inhibitor in metal cleaning agents, and it also has a certain cleaning effect. Additives such as defoamers, solubilizers, stabilizers and other inorganic salts should also be added to metal cleaning agents. Sometimes, in order to improve the appearance and quality of the product, small amounts of flavors, brighteners, fluorescents, antifungal agents, and pigments can also be added to the cleaning agent.

Formula screening results: For the development of a weak alkaline aqueous metal oil cleaning agent, to achieve the purpose of high cleaning rate, low corrosiveness, low cleaning temperature, non-toxic, non-polluting, etc., it is very important for the screening and compounding of surfactants, to ensure that the HLB value of various surfactants after compounding is in the range of 9.0 - 13. Finally, it was determined that nonionic surfactants such as fatty alcohol ethoxylates and alkylphenol ethoxylates were the mainstay, and they were compounded with anionic surfactants such as potassium dodecyl phosphate, tedecyl ethoxyethylene ether monoester sulfonate succinate and AES. Using the synergistic effect of various alkaline salt additives, potassium pyrophosphate, borax, etc. are selected. The corrosion inhibitors used are potassium silicate, benzotriazole, etc. For example, the filtered formulation:

The concentrate can be diluted 20-30 times, while aluminum and alloys must be mixed with a certain amount of silicate before dilution for use.

Performance result test: PH value, high and low stability The appearance, PH value, high and low temperature resistance of the metal cleaning agent directly prepared with tap water with 3% cleaning test solution were tested.

Taking into account the cost, the optimal use temperature of this formula is 60 degrees and the washing time is 2 minutes.

The data collation comes from the Internet, and the water-based metal cleaning agent is of great significance in the field of metal processing and cleaning. The development process needs to be considered from many aspects.

First, the systematization of the development process

Determine the cleaning object and requirements, etc

This is the basic step of development. Clarify the cleaning object, requirements and dosage form, which can point out the direction for subsequent work. For example, knowing whether to remove rust or oil can be carried out in a targeted manner.

Data search and market research

Find relevant information, patents, and conduct market research. This helps to understand existing technologies and market needs, avoid duplication of effort, and also provide a basis for product positioning.

Cleaning process and evaluation method

Understanding the cleaning process and establishing a laboratory performance evaluation method is key. Only when a suitable evaluation method is established can the performance of the cleaning agent be accurately evaluated.

Determination and analysis of basic components

Determine the basic composition and dissect the sample if necessary. This can be used as a reference for the initial construction of the formulation, for example to determine which main ingredients are needed.

Recipe screening and basic recipe establishment

Establish a base formulation through screening assays. This process involves the selection and determination of the proportion of a variety of ingredients, such as surfactants, alkalis and alkaline salts.

Field application test and validation

Field application trials validate the base formulation and identify problems and deficiencies. This is an important transition from the lab to the real world.

Formulation improvement and styling

Based on the results of field application tests, the formulation is refined and finalized, while paying attention to the performance/price ratio. Ensure that the product has good performance and market competitiveness at the same time.

Measurement of performance indicators and test of use conditions

Determine the performance indicators, conduct the test of the use conditions, and determine the problems that need to be paid attention to in use. This helps to provide users with accurate instructions on how to use it.

Scale-up tests for field applications

Further validate the viability and stability of the product in a larger-scale field application.

Drafting of enterprise standards

Drafting enterprise standards to standardize the production and quality control of products.

Promote application and technical services

Promote the application of products and test marketing, and do a good job in technical services. This helps the product to enter the market and gain user acceptance.

Identification and sales of new products

After identification, the product can reach the sales stage, marking the final completion of product development.

2. Characteristics and composition considerations of water-based metal cleaning agents

Requirements met

Metal cleaning agents need to have good surface activity, such as wetting, solubilization and emulsifying ability, strong oil removal ability and no oil film or oil spots after cleaning; It is non-corrosive to metal and maintains metal luster after cleaning; There is a certain anti-rust ability; The process performance is good, the operation is simple, the temperature is low, it is easy to wash, it does not pollute the environment and the three wastes are convenient to treat.

Consideration of components in formulations

Surfactant: Choose the appropriate surfactant according to the dirt structure of the cleaning object, generally aliphatic or aromatic derivatives with aliphatic hydrocarbons, and the HLB value is between 8 - 16. A variety of surfactants are more effective, and resource and cost factors should be considered, such as triethanolamine oleate, alkyl phosphate and other commonly used surfactants.

Alkali and alkaline salts: alkali and alkaline salts can be used as cleaning agents alone or as additives into surfactants, and the cleaning effect on dirt such as animal and vegetable oils and fats is obvious, but it has a corrosive effect on some metals, and caustic soda, sodium carbonate, etc. are commonly used.

Antirust and corrosion inhibitor: including inorganic and organic, can be used in combination. Such as sodium nitrite, sodium benzoate, etc., can meet the requirements of no corrosion during cleaning, corrosion inhibition and rust prevention after cleaning.

Defoamer: Because low foaming or no foaming is required for cleaning, it is necessary to add defoamer, such as polyether 2010, tributyl phosphate, etc., but its impact on the degreasing ability should be considered when screening.

3. Establishment of cleaning effect measurement method

Preparation of metal specimens

The specifications and sizes of various metal specimens are specified, such as the size of 45 gauge steel sheets is 50 mm to 50 mm (3 - 5) mm, and there are detailed grinding, cleaning and drying steps.

Preparation of test solution

According to different test types, such as corrosiveness, rust resistance, etc., distilled water or deionized water is prepared at 3%, and 250mg/kg hard water is prepared at 3% for net washing power, foam and other tests.

Determination of washing power

The pendulum washing machine is used to measure the cleaning power, and the swing frequency of the pendulum washing machine is specified to be (40±2) times/minute, and the swing distance is (50±2) mm, and the detailed steps such as preparation, coating, test procedure, cleaning power calculation and result evaluation of artificial oil stain are also included.

Other performance tests

Corrosivity test: The corrosivity is evaluated by immersing the metal specimen in a certain temperature of the cleaning solution and observing the changes in the appearance and quality of the specimen, and there are detailed test procedures and result evaluation standards.

Anti-rust test: The test piece is immersed in the test solution, then dried, put into the humid heater, etc., and finally the appearance is checked and evaluated according to the standard.

Foam performance test: measured by Roche foam meter, the metal cleaning agent is required to be low foam, and there is a specific foam height standard.

High and low temperature stability test: including high temperature test (60 degrees constant temperature water bath for 6 hours) and low temperature test (minus 5 degrees refrigerator for 24 hours) to observe the appearance change.

Determination of water volatiles: The moisture and volatile content are determined by calculating the weight loss number after drying the sample in an oven.

Rinsing performance test: The specimen is immersed in the test solution, dried and washed in distilled water, and finally the appearance of the specimen is checked.

PH VALUE DETERMINATION: USE PH VALUE METER OR PH PAPER MEASUREMENT, THERE ARE DIFFERENT PH VALUE REQUIREMENTS FOR DIFFERENT METAL DETERGENTS.

Fourth, the screening of metal cleaning agent formula

surfactant

The cleaning effect is related to the type of object to be washed, the nature of the dirt and the temperature, etc., and the combined use of nonionic surfactant and anionic surfactant has a synergistic effect. It is necessary to pay attention to factors such as HLB value and cloud point, and at the same time, there is a contradiction between the cleaning power and rust resistance of the surfactant, and the soft and hard water and temperature have an impact on the cleaning power of the surfactant.

Alkaline and alkaline salts

The properties of different alkalis and alkaline salts, such as PH value, washing, penetration, dispersion, emulsification, flushing, hard water resistance and corrosion resistance, etc., should be considered when selecting, such as the reaction of sodium carbonate in hard water, the advantages of silicates, the excellent properties of polyphosphate, etc.

Compound of various surfactants

A variety of surfactants, such as AEO-9 and AES, were selected for compounding tests, and it was found that the cleaning power of the compound LAS-Na was poor, and the compounding effect of nonionic surfactants was good.

Surfactant and alkaline salt compound

The combination of surfactant and alkaline salt can improve the cleaning power, and some surfactants are selective to alkaline substances, such as LAS-Na with sodium orthosilicate can improve the cleaning power best, and TX-10 can be greatly improved after adding alkaline substances.

The addition of anticorrosive corrosion inhibitors and other additives

Different corrosion inhibitors can be added for different metal parts, such as sodium nitrite can be added to steel parts, benzotriazole can be added to copper parts, etc. Other additives such as defoamers and solubilizers can also be added, and sometimes substances such as flavors can be added to improve the appearance and quality of the product.

Recipe screening results

To ensure that the HLB value after compounding is in the range of 9.0 - 13, it is determined that the nonionic surfactant is the main one, compounded with anionic surfactant, and the alkaline salt additives are used synergistically to select the formula of specific corrosion inhibitors, and the metal cleaning agent of the formula meets the requirements in terms of PH value, high and low stability and other properties, the optimal use temperature is 60 degrees, and the cleaning time is 2 minutes. The development of metal cleaning agents is a systematic and complex process, involving multiple aspects of consideration and operation.

**First, the importance and integrity of the development process**

1. **Basic Planning Session**

   - Defining the cleaning object, requirements and dosage form is the beginning of development. This link is like the blueprint planning of the building, determining whether the requirements such as rust removal or oil removal are determined, and setting the direction for the subsequent work. In metalworking, for example, this initial decision will guide the entire development direction for different metal products and dirt types.

   - Data search and market research are key to avoiding duplication of effort and positioning products accurately. By searching for relevant information and patents, we can understand the development level of the existing technology, and at the same time conduct market research to grasp the market demand for metal cleaning agents in terms of performance, price, environmental protection, etc., so as to provide a basis for product research and development and ensure that the developed products are competitive in the market.

2. **Construction of core links**

   - The determination of cleaning process and evaluation method is the core link of development. Establish appropriate laboratory performance evaluation methods, such as cleaning power, corrosiveness, rust resistance, etc., to accurately measure the performance of cleaning agents. It's like establishing a precise testing standard for a product, and only by this standard can the qualified formula be screened out.

   - Determination and analysis of basic components is an important reference for recipe construction. Determining the basic components of the cleaning agent and dissecting the sample if necessary can determine which main components are needed, such as surfactants, alkaline and alkaline salts, rust inhibitors, etc., to lay the foundation for the initial formulation construction.

3. **Recipe Optimization & Validation**

   - Formulation screening and basic formulation establishment involve complex selection and proportioning of multiple ingredients. Screening and proportioning of numerous surfactants, alkalis and alkaline salts and other ingredients to find a preliminary feasible basic formula through a large number of experiments. It's a process of trial and error, and it takes into account the interactions and influences of the various ingredients.

   - Field application testing and validation is the bridge from the laboratory to the real world. Testing the basic formula in a real-world use scenario can uncover problems and deficiencies that cannot be exposed in a laboratory environment, such as in an actual metalworking shop, where different metal materials, dirt levels, cleaning equipment, etc., may be encountered, which can affect the effectiveness of the cleaning agent.

   - Formulation improvement and finalization should be based on both performance and price. Based on the results of field application trials, the formulation is improved to achieve the best performance of the product, while also considering the cost factor to ensure that the product is competitive in the market. For example, if an ingredient improves performance but costs too much, you need to look for more cost-effective alternatives.

4. **Product Improvement and Market Access**

   - Performance index measurement and usage condition test provide users with accurate usage guidelines. Determine the performance indicators of the product, such as PH value, high and low temperature stability, etc., and determine the precautions under different use conditions, such as the best use temperature, cleaning time, etc., which helps users to use the product correctly and improve the use effect and life of the product.

   - Scale-up tests are applied in the field to further verify the feasibility and stability of the product. Test products in larger-scale real-world application scenarios to ensure that there are no problems during mass production and use, such as trials in large metal processing companies to verify the performance and stability of products in large quantities.

   - Corporate standard drafting regulates the production and quality control of products. Through the formulation of enterprise standards, clear product quality requirements, production processes, inspection methods, etc., to ensure the quality of products is stable and reliable, but also to provide a basis for the production management of enterprises.

   - Promoting applications and technical services is a key step in getting a product to market. Through the promotion of products, trial marketing and the provision of technical services, let users understand and accept the products, solve the problems encountered by users in the process of use, and improve the reputation and market share of the products.

   - Identification and sale of new products marks the final completion of product development. After strict appraisal, the product meets the sales conditions, officially enters the market, and realizes the transformation from R&D to the market.

**2. Detailed consideration of the characteristics and components of aqueous metal cleaning agents**

1. **Comprehensiveness of Feature Requirements**

   - Good surface activity of metal cleaners is the basis for effective cleaning. With the ability of wetting, solubilization and emulsification, it can make the cleaning agent better contact with the oil stain and remove it, and at the same time, there is no oil film or oil spot after cleaning, ensuring the high quality of the cleaning effect.

   - Non-corrosive to metal and maintaining luster is an important requirement for the protection of metal products. In the cleaning process, the cleaning agent can not cause damage to the metal, and the cleaned metal surface should maintain the original luster, which is particularly important for some metal products with high requirements for appearance, such as precision instruments, decorations, etc.

   - A certain anti-rust ability prevents the metal from rusting. After cleaning, the metal will not appear rust spots when the supply and demand are transferred during processing, and no additional anti-rust treatment is required, which not only facilitates the production process, but also reduces production costs.

   - Good process performance makes cleaning operation convenient and efficient. It is easy to operate, low in temperature, easy to wash clean, does not pollute the environment and is convenient for the treatment of three wastes, which meets the requirements of modern industry for environmental protection and efficient production. For example, low operating temperatures reduce energy consumption, and easy cleaning reduces the number of post-cleaning treatment steps.

2. **Scientific Component Consideration**

   - The choice of surfactant depends on the structure of the dirt and a variety of factors. Aliphatic or aromatic derivatives with aliphatic hydrocarbons are selected as surfactants, depending on the main composition of the dirt to be cleaned, and the HLB value is controlled between 8 and 16. At the same time, considering that the compound effect of a variety of surfactants is better, it is also necessary to take into account the resource and cost factors, and choose commonly used surfactants such as triethanolamine oleate and alkyl phosphate to achieve the best cleaning effect.

   - Alkaline and alkaline salts have both effects and limitations. Alkali and alkaline salts can have a significant cleaning effect on dirt such as animal and vegetable oils and fats, but have a corrosive effect on some metals. Therefore, when selecting, it is necessary to weigh according to the metal material of the cleaning object, and the commonly used caustic soda and sodium carbonate have different applicability in different cleaning scenarios.

   - Anti-rust and corrosion inhibitors meet the dual needs of cleaning and rust prevention. It contains two types of inorganic and organic anti-rust and corrosion inhibitors, which can be used in combination, such as sodium nitrite, sodium benzoate, etc. These corrosion inhibitors can ensure that there is no corrosion to the metal during cleaning, and form a protective film on the metal surface after cleaning, which plays a role in corrosion inhibition and rust prevention.

   - Defoamer selection takes into account the ability to remove grease stains. Since low foaming or no foaming is required for cleaning, it is necessary to add defoamers, such as polyether 2010, tributyl phosphate, etc. However, when screening defoamers, consider their impact on the ability to remove grease stains to ensure that the foam is eliminated without compromising the cleaning effect.

**3. Accuracy and completeness of the cleaning effect measurement method**

1. **Standardization of metal specimen preparation**

   - Specify detailed specifications and dimensions for a variety of metal specimens, such as 50 mm× 50 mm× (3 - 5) mm for 45 gauge steel sheets, and have strict grinding, washing, and drying steps. These standardized practices ensure the consistency and accuracy of the specimens, providing reliable samples for subsequent tests.

2. **Pertinence of test solution preparation**

   - According to different test types, such as corrosiveness, rust resistance, etc., distilled water or deionized water is prepared at 3%, and 250mg/kg hard water is prepared at 3% for cleaning power, foam and other tests. This targeted preparation of test solution can more accurately simulate the actual cleaning environment and conditions, making the test results more valuable for reference.

3. **Meticulous process of washing power measurement**

   - Determine the cleaning power with a pendulum washing machine, specify the swing frequency of the pendulum washer (40±2) times/minute, and the swing distance of (50±2) mm, and also include detailed steps such as preparation, coating, test procedures, calculation of cleaning power and evaluation of artificial oil. This meticulous process ensures the accuracy and reproducibility of the cleaning power determination, providing a reliable way to evaluate the cleaning capacity of the cleaning agent.

4. **Systematization of other performance tests**

   - The corrosivity test evaluates the corrosivity by immersing the metal specimen in a cleaning solution at a certain temperature and observing the changes in the appearance and quality of the specimen, and there are detailed test procedures and result evaluation standards. This test accurately assesses the degree of corrosion of the cleaning agent to the metal, ensuring that the product does not cause damage to the metal during use.

   - Rust resistance test: The specimen is immersed in the test solution, then dried, put into a humid heater, etc., and finally the appearance is checked and evaluated according to the standard. This kind of rust resistance test simulates the actual environment, which can effectively test the rust resistance of the cleaning agent.

   - The foam performance test is determined by a Roche foam tester, which requires the metal cleaning agent to be low foam and has a specific foam height standard. This test ensures that the cleaning agent does not produce too much foam during use, which affects the cleaning effect and the normal operation of the cleaning equipment.

   - The high and low temperature stability test includes a high temperature test (60 degrees Celsius constant temperature water bath for 6 hours) and a low temperature test (minus 5 degrees Celsius refrigerator for 24 hours) to observe the appearance change. This test can check the stability of the cleaning agent in different temperature environments to ensure that the product can be used normally in different use environments.

   - Determination of water volatiles: Moisture and volatile content are determined by calculating the weight loss number after drying the sample in an oven. This assay helps to understand the stability and quality of the product, ensuring that the product will not be affected by water volatiles during storage and use.

   - Rinse performance testThe specimen is immersed in the test solution, dried, washed in distilled water, and finally the appearance of the specimen is checked. This test can be used to check whether the cleaning agent is easy to rinse clean after cleaning and to avoid the adverse effects of residual cleaning agent on the metal products.

   - PH value measurement is measured with a pH meter or PH paper, and there are different PH requirements for detergents for different metals. This determination ensures that the pH of the cleaning agent is within the appropriate range to meet the cleaning requirements without damaging the different metal materials.

**Fourth, the multi-factor comprehensive consideration of metal cleaning agent formula screening**

1. **Complex properties of surfactants**

   - Cleaning results are affected by a variety of factors. The cleaning effect of surfactants is closely related to factors such as the type of object to be washed, the nature of the dirt and the temperature. For example, different types of dirt and different metal materials require different surfactants to achieve the best cleaning results.

   - Synergies of compound use. The combination of nonionic surfactants and anionic surfactants has a synergistic effect to enhance emulsification, solubilization, dispersion and cleaning. However, when using in combination, it is necessary to pay attention to factors such as HLB value and cloud point to ensure the stability and effectiveness of the surfactant in the cleaning process.

   - Contradiction between cleaning power and rust resistance. There is a contradiction between the cleaning power and rust resistance of surfactants, and these two factors need to be balanced when choosing surfactants. For example, some surfactants, although they have better cleaning power, may reduce rust resistance, and this problem needs to be solved through reasonable compounding.

   - Effect of hard and soft water and temperature. Hard and soft water and temperature have an impact on the cleaning power of surfactants, and nonionic surfactants have strong resistance to hard water, which is generally not affected by the hardness of water, but water hardness has a great impact on the cleaning power of anionic surfactants. At the same time, temperature also has different effects on the cleaning power of different types of surfactants, such as nonionic surfactants are basically not affected by temperature, but when the temperature exceeds the cloud point, the cleaning power will decrease.

2. **Performance Difference Trade-off Between Alkali and Alkaline Salts**

   - The properties of different bases and alkaline salts vary. Different alkalis and alkaline salts have differences in PH value, washing, penetration, dispersion, emulsification, flushing, hard water resistance and corrosion resistance, etc., for example, sodium carbonate will generate insoluble calcium carbonate in hard water, and sodium bicarbonate will react with calcium ions to form soluble calcium bicarbonate, which has a certain softening ability to hard water. Silicates have good hard water resistance and dirt dispersion ability, and have the effect of preventing dirt from re-adhesion; Polyphosphate has a low alkalinity, can soften hard water, has a strong dispersion force, can prevent metal corrosion, and also has the effect of preventing dirt adhesion. When choosing alkali and alkaline salts, there is a trade-off between the specific cleaning requirements and the metal material.

3. **Analysis of the effect of surfactant compounding**

   - Different surfactants have different effects. A variety of surfactants, such as AEO-9 and AES, were selected for compounding tests, and it was found that the cleaning power of the compound LAS-Na was poor, and the compounding effect of nonionic surfactants was good. This indicates that when formulating surfactants, it is necessary to select the appropriate combination of surfactants to improve the cleaning power.

4. **Selectivity of surfactants and alkaline salts**

   - Surfactant and alkaline salts are formulated to improve cleaning power. Some surfactants are selective for alkaline substances, such as LAS-Na with sodium orthosilicate with the best cleaning power, while TX-10 with alkaline substances can greatly improve the cleaning power. This selectivity needs to be taken into account when formulating surfactants and alkaline salts in order to achieve the best possible cleaning power boost.

5. **Reasonable addition of anticorrosive corrosion inhibitors and other additives**

   - Add different corrosion inhibitors for different metal parts. For different metal parts, such as sodium nitrite can be added to steel parts, benzotriazole and other corrosion inhibitors can be added to copper parts. This targeted addition ensures that different metal parts can be cleaned with both a cleaning effect and an effective prevention of metal corrosion.

   - The role of other additives. In addition to corrosion inhibitors, other additives such as defoamers and solubilizers can also be added, and sometimes substances such as flavors can be added to improve the appearance and quality of the product. The addition of these additives can further optimize the performance of the product and improve the overall quality of the product.

6. **Comprehensive consideration of formula screening results**

   - In the development of weak alkaline aqueous metal oil cleaning agent, it is very important for the screening and compounding of surfactants, to ensure that the HLB value after compounding is in the range of 9.0 - 13, and the formulation of nonionic surfactants is determined, compounded with anionic surfactants, and the synergistic effect of alkaline salt additives is used to select specific corrosion inhibitors. This formula meets the requirements in terms of pH value, high and low stability and other properties, with an optimal use temperature of 60 degrees and a cleaning time of 2 minutes. The results of this formulation screening are based on a comprehensive consideration of the characteristics and interactions of various components such as surfactants, alkali and alkaline salts, rust inhibitors, etc., and can meet the various requirements of metal oil cleaning.