1. A basic formula of artificial dirt for researching a vehicle surface cleaning technology is characterized in that: the composite material comprises the following raw materials in parts by weight:

2. the formulation according to claim 1, wherein the formulation comprises at least one of the following components: the non-metallic mineral powder is any one of montmorillonite powder, kaolin powder and nano calcium carbonate powder.

3. The formulation according to claim 1, wherein the formulation comprises at least one of the following components: on the basis of the components of the basic formula, metal oxide powder with the mesh number of more than 3000 meshes is added.

4. The formulation according to claim 3, wherein the formulation comprises at least one of the following components: the metal oxide powder is an oxide of iron and copper.

5. Method for making artificial soils according to the artificial soil base formulation of any of claims 1 to 4, characterized in that: preparing the artificial dirt basic formula into an artificial dirt aqueous solution, and spraying the aqueous solution on the surface of a vehicle body according to the following process steps to finally prepare a surface dirt layer required by the test:

s1, thoroughly cleaning the surface of the vehicle body to be tested;

s2, shaking the artificial dirt water solution evenly, and spraying the water solution to the surface of the vehicle body in a water mist shape;

s3, naturally drying, or drying by electric blowing after a layer of thick paper soaked by water is covered on the surface of the vehicle body;

s4, before a cleaning test, washing the surface of the sample by using clear water with the pressure of more than 5 MPa;

and S5, drying the surface, and using the surface for cleaning test.

6. The method of making artificial soil according to claim 5, wherein: the mist-like spraying of the spraying process S2 is carried out using an electrostatic atomizer.

7. The method of making artificial soil according to claim 5, wherein: the clear water used in the spraying process S4 is added with a surfactant, and the concentration of the surfactant is between 0.5 per mill and 5 percent.

8. The method of making artificial soil according to claim 7, wherein: the surfactant is any one of commonly used liquid detergent and liquid laundry detergent products or single sodium alkyl sulfonate and fatty alcohol ether sodium sulfate surfactants.

9. The method of configuring an aqueous artificial soil solution according to claim 5, wherein: the preparation of the basic formula comprises the following four steps:

s1, premixing: uniformly mixing solid matters such as non-metal mineral powder, xanthan gum and the like in the components;

s2, slowly adding water while stirring;

s3, adding lubricating oil and fully stirring;

and S4, putting the mixture into an ultrasonic emulsification instrument for full emulsification.

Background

When people research the cleaning technology of the surface of an automobile, if the dirt on the surface of the automobile body formed naturally is adopted, the dirt is not easy to obtain, the result comparability is not strong due to different front and back test conditions, the test efficiency and the data validity are greatly reduced, and the test is not strict. Such as dirt on the surface of the vehicle body, the components are complex and diverse: there are large particle dust, PM2.5 and lower particle fine dust settled in the atmospheric environment, bird droppings, leaf residues, automobile exhaust aerosol, vehicle tire powder or brake powder, and the settling modes include road muddy water splashing, rainfall, fog deposition, airflow wall-attaching effect adhesion, electrostatic adsorption, and the like. In terms of the automobile body part, the upper part of the automobile body is mostly ultrafine dust, the lower part of the automobile body is mostly mud, the automobile head is provided with corpses, and the wheel hub is provided with brake pad powder. Briefly, the composition of the body dirt includes: inorganic minerals, metal oxides, and organic substances remaining from animals and plants may be in the form of large solid particles or a thin film layer.

For this reason, the problem of consistency of the dirt to be tested needs to be solved. But the manufacturing technology of artificial dirt aiming at the dirt on the surface of the automobile is lacked at present. The practical difficulties are: in the case of the naturally occurring dirt on the vehicle body, there is almost no cleaning effect even when high-pressure water of 13MPa is used. In contrast, if only solid-liquid contaminants such as clay, dust, leaves, sewage, and lubricating oil are generally applied to the vehicle body, only surface dirt having extremely weak adhesion is formed, and the dirt can be removed by a slight flush with high-pressure water of 5MPa or less. Alternatively, the physical and chemical properties of the fouling layer are far from the reality. Therefore, it is not feasible to simply spray the contaminants onto the surface of the car body to produce artificial stains, and the formulation and manufacturing process of the artificial stains need to be proposed by combining theory and experiment on the basis of researching the components of the stains, the mechanism of adhesion of the stains and the mechanism of damage of the stains.

In order to solve the problems, the scheme is developed accordingly.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a method for manufacturing artificial dirt used in the research of a vehicle surface cleaning technology, aiming at preparing a vehicle washing liquid and manufacturing the artificial dirt on the surface of an automobile body by a certain process for a cleaning test, and realizing a cleaning effect which is better comparable to the actual dirt under the condition of the artificial dirt.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a method for preparing artificial dirt used for researching the surface cleaning technique of vehicles, the dirt is prepared by firstly mixing the following components in parts by weight as a basic formula to prepare an aqueous solution:

the non-metallic mineral powder in the basic formula can be one of montmorillonite powder, kaolin powder and nano calcium carbonate powder, or a mixture of more of montmorillonite powder, kaolin powder and nano calcium carbonate powder. On the basis of the components of the basic formulation, metal oxide powders with a mesh number of more than 3000 can be added, such as: nano-scale iron and copper oxides.

The components are mixed in four steps when preparing the aqueous solution:

s1, premixing: uniformly mixing solid matters such as non-metal mineral powder, xanthan gum and the like in the components;

s2, slowly adding water while stirring;

s3, adding lubricating oil and fully stirring;

and S4, putting the mixture into an ultrasonic emulsification instrument for full emulsification.

After the aqueous solution is prepared, it can be stored for use, and is fully homogenized by shaking before use. The aqueous solution of the artificial dirt is sprayed on the surface of the vehicle body according to the following process steps to finally manufacture a surface dirt layer required by the test:

s1, thoroughly cleaning the surface of the vehicle body to be tested;

s2, shaking the artificial dirt solution evenly, and spraying the solution to the surface of the vehicle body in a water mist shape;

s3, naturally drying, or drying by electric blowing after a layer of thick paper soaked by water is covered on the surface of the vehicle body;

s4, before a cleaning test, washing the surface of the sample by using clear water with the pressure of more than 5 MPa;

and S5, drying the surface, and using the surface for cleaning test.

Preferably, the apparatus used for spraying the water mist in the spraying process S2 is an electrostatic atomizer. The clear water used in the spraying process S4 is added with a surfactant, and the concentration of the surfactant is between 0.5 per mill and 5 percent. The surfactant can be common liquid detergent, liquid laundry detergent products or single surfactants such as sodium alkyl sulfonate, fatty alcohol ether sodium sulfate and the like.

In the formula of the artificial dirt, the nonmetallic minerals do not rapidly react with detergents such as car washing liquid and the like, and the adhesion and the hydrophilic and oleophilic characteristics of the car-watching paint are mainly selected; the engine lubricating oil can simulate oil-gas components in automobile exhaust and can also strengthen the adhesion of the whole solution system and the surface of the automobile paint, and the specific dosage needs to consider the oil absorption of mineral substances; xanthan gum is the biological gum with excellent performance which integrates thickening, suspending, emulsifying and stabilizing at present, can be dissolved in cold water, and has simple and rapid process when preparing aqueous solution.

The xanthan gum has thickening property, thermal stability, acid-base stability, good compatibility with various salts, and good suspension effect on insoluble solids and oil drops. The pseudoplasticity of the xanthan gum ensures that the prepared solution has good solid-phase suspension characteristics, and the solid components are not easy to settle at the bottom and harden after long-term storage. In addition, xanthan gum can be used as an emulsifier to prevent oil-water separation.

Ultrasonic emulsification can realize an emulsion in which two or more immiscible components are uniformly mixed. Compared with manual oscillation, mechanical stirring and other modes, the liquid drops in the oil-in-water/water-in-oil dispersion system after ultrasonic emulsification treatment are finer and can reach less than 10 mu m, and the emulsion is more stable and is easy to store for a long time.

The electrostatic spray promotes the adsorption of the micro-scale dirt and the surface of the vehicle body by electrostatic attraction, and can quickly cover and penetrate into gaps. Compared with the process of sedimentation and accumulation caused by the gravity, the electrostatic adsorption device has stronger adhesive force and is more uniform, and the electrostatic adsorption process is well simulated. In particular, when the body naturally adsorbs dirt, the dirt adhesion force increases with time. The electrostatic spraying process can greatly accelerate the deposition process of artificial dirt, quickly reach a stable adhesive force state, save the aging process of the artificial dirt and obviously improve the test efficiency.

After the emulsion of the artificial dirt is dried, a surfactant is added into clean water used for primary cleaning. The surfactant is preferably selected to have a weaker effect than that of a formal car wash, and the concentration of the surfactant is not high enough. The main function is to promote the dirt washed and dropped off in the step to be emulsified and suspended in the water body, and avoid being redeposited on the surface of the artificial dirt.

Normally, the aqueous solution of the artificial dirt can be air-dried naturally on the surface of the vehicle body. Sometimes, in order to rapidly prepare the dirt, the dirt may be air-dried by means of manual heating with an electric blower. Under the condition, the key is to cover a piece of paper on the surface layer of the dirt, so that the dirt is prevented from being directly heated and quickly dried by electric air blowing, the penetration process of the dirt on the surface of the vehicle paint for a certain time at a higher temperature is ensured, the intermolecular acting force is enhanced, and the dirt is prevented from being distorted due to too fast dehydration and drying when the artificial dirt is quickly prepared.

(III) advantageous effects

After adopting the technical scheme, compared with the prior art, the invention has the following advantages: the artificial dirt formula and the construction process thereof provided by the invention are proved to have strong adhesive force through a large number of material screening and cleaning tests, have the adhesive property similar to that of traffic oil films and other dirt difficult to wash, can be used as a reference object for vehicle washing liquid and high-pressure water cleaning process research, provide a simple and available high-simulation dirt surface for actual research and development, are simple to operate, have low cost and good consistency, and have strong practical application value.

Detailed Description

The present invention is further illustrated by the following specific examples.

Example 1:

the first step is to prepare an artificial soil emulsion. 50 g of montmorillonite powder and 5 g of xanthan gum are uniformly mixed and placed in a container, and 1000 g of water is gradually added while stirring, so that the xanthan gum is completely dissolved and does not agglomerate to form an aqueous solution. Then, 15 g of engine oil was added and stirred well. Then, the mixture was put into an ultrasonic emulsifier and shaken for 30 mins. Then, the mixture is placed in a container for standby. If the aqueous solution is stored for a long time, the aqueous solution can be used after being treated by the ultrasonic emulsifier again except shaking.

And secondly, thoroughly cleaning the surface of the vehicle body part to be tested. Then, the artificial dirt emulsion is sprayed to the vehicle body by an electrostatic sprayer and then naturally dried. The process of this step may be repeated multiple times to strengthen the fouling layer.

And thirdly, preparing sufficient clear water, adding detergent according to the proportion of 5 per mill, and washing the surface of the dirt for 15 seconds under the pumping pressure of 8 MPa. The specific flush time is determined based on the characteristics of the soil to be tested. And then, naturally drying or blow-drying by a hair drier.

Thus, the artificial dirt surface for the subsequent cleaning test is formally manufactured.

The montmorillonite powder is an important clay mineral, is a layered mineral formed by water-containing aluminosilicate, has fine particles of about 0.2-1 micron, and has a colloid dispersion characteristic. Montmorillonite is difficult to aggregate into large particles in solution, and has excellent dispersibility and suspension property; the suspension has certain viscosity, thixotropy and lubricity; the Mohs hardness is 1-2, and the density is 2-3 g/cm 3; the mixture is not mildewed and rotten when placed, has a certain adsorption effect and realizes a good mixing effect. After drying, the micro-nano montmorillonite powder particles are attached to the surface of the vehicle body, and the cleaning effect is easy to identify.

Example 2:

the non-metallic mineral powder in the basic formula adopts kaolin powder. Kaolin is a common clay mineral, mineral components mainly comprise kaolinite, montmorillonite and the like, the texture is fine, a large amount of solid particles with the particle size of less than 2 microns are contained, the continuous particle size distribution is good, the drying strength is good, and therefore the deposition effect of fine-grained dust such as PM2.5 and the like can be well simulated. The kaolin has strong water absorption, good suspension property, dispersibility and cohesiveness, and is beneficial to preparing a solid-liquid two-phase mixed solution with uniform texture.

Example 3:

the non-metallic mineral powder in the basic formula adopts nano calcium carbonate powder. The nano calcium carbonate can greatly improve the adhesive force and the washing resistance of the solution due to the special small-scale effect, and has good anti-settling effect. As a formulation, the surface adhesion of artificial dirt, especially to non-polar substances such as automotive paints, can be improved.

The doping effect of the fine powder of the above 3 examples in artificial dirt is comparable to the mineral content of atmospheric dust.

Example 4: the iron oxide powder is added to the basic formula and sprayed on the surface of a wheel hub or a similar metal sample to prepare artificial dirt for a wheel hub cleaning test.

Practice proves that the standard artificial dirt manufactured according to the method has good similarity with dirt naturally formed on an automobile body, certain representativeness, good repeatability and consistency of repeated use, simple and convenient operation and low cost, can be prepared in a large scale at one time and stored for a long time, and effectively meets the practical requirements of various cleaning test researches.

The non-metallic minerals used in the above examples are only preferred examples. According to the research requirement, the mixture of various non-metal mineral powders can be adopted; other materials such as double-flying powder, putty powder, carbon black and the like can be adopted, but the practical problems of various raw material specifications, poor quality consistency and the like can be solved, but the essence of the method is not violated. According to the difference and the characteristics of road dust in various places, other materials such as fly ash and the like can be added for improvement and optimization.

According to the embodiment, different formulas are adopted according to the difference of components and formation reasons of dirt at different parts of the automobile body, so that a good dirt simulation effect can be achieved.

The electrostatic sprayer used in the invention has mature products, has different charging modes and different performances, belongs to the known technology, and is not described in detail herein. The test object in the foregoing description is a "vehicle body", which is only for the sake of simplicity, and may actually be a specially prepared sample, such as: a small piece of automotive glass or painted hardware/plastic, with no essential differences.

The invention provides a formula and a process for rapidly preparing artificial dirt, which are based on the microscopic analysis of the actual dirt of the automobile body and deeply grasp the formation mechanism and the surface adhesion mechanism of the dirt. In specific application, the artificial dirt can be used for testing the decontamination performance of different chemical detergents and can also be used for testing the cleaning effect of different cleaning processes or equipment.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and the protection scope must be determined by the scope of the claims.