CN107779301B

CN107779301B - Aerospace precision industrial cleaning agent

Info

Publication number: CN107779301B
Application number: CN201710812539.0A
Authority: CN
Inventors: 黄玲; 李登臣
Original assignee: Beijing Aerospace Yisen Wind Tunnel Engineering Technology Co ltd
Current assignee: Beijing Aerospace Yisen Wind Tunnel Engineering Technology Co ltd
Priority date: 2017-09-11
Filing date: 2017-09-11
Publication date: 2020-09-18
Anticipated expiration: 2037-09-11
Also published as: CN107779301A

Abstract

The invention discloses a cleaning agent for aerospace precision industry, which comprises the following components in percentage by mass: 85-95% of dichloromethane; 0-15% of ethanol; and 0-15% of ethyl acetate. The invention has fast dirt cleaning speed and thorough dirt dissolving; the adopted components are cheap and easy to obtain, the cleaning cost is low, and excessive resource consumption is avoided; the cleaning agent has low toxicity to organisms and environment; the cleaning condition is mild and does not depend on the strengthening condition; the cleaning agent is not flammable and explosive, the cleaning agent is phosphorus-free and environment-friendly, and the COD value is reduced; insoluble substances are not left on the surface of a cleaning object in the cleaning process, new dirt is not generated, a new covering layer harmful to the subsequent process is not formed, the quality of products is not influenced, and foams and peculiar smell influencing the cleaning process and the site sanitation are not generated.

Description

Aerospace precision industrial cleaning agent

Technical Field

The invention belongs to the field of cleaning agents, and particularly relates to an aerospace precision industrial cleaning agent for degreasing and cleaning precision aerospace pipe fittings.

Background

The cleaning agent is a large range and various in types, including inorganic cleaning agents and organic cleaning agents, wherein the organic cleaning agents are cleaning agents made of carbon-containing compounds, and the inorganic cleaning agents are cleaning agents made of carbon-free compounds. The cleaning agent is classified into a cleaning agent (water-based type), a cleaning agent (semi-water-based type), and a cleaning agent (solvent type) according to the difference of the solvent.

The cleaning agent (water-based type) is a substance which is composed of a surfactant, various auxiliaries and auxiliaries, and can reduce the surface tension of an aqueous solution and improve the detergency effect when washing dirt on the surface of an object. The detergent is divided into solid detergent and liquid detergent according to the appearance form of the product. Solid detergents are produced in large quantities and are customarily called washing powders, including fine powders, granules, hollow granules, etc. The hollow granular solid detergent is produced by high tower spray drying process including the main steps of slurry preparation, spray drying, wind ageing and packing. The liquid detergent is easy to manufacture, and only the surfactant, the auxiliary agent and other additives, and the treated water are fed into a mixer to be mixed.

Water is the most important cleaning agent and has the function and position that any other cleaning agent cannot replace. Ordinary water is easily obtained from nature and has strong dissolving power and dispersing power. However, water has a high surface tension, and a surfactant is required to be added in use to reduce the surface tension and increase the surface wettability. In general industrial cleaning, the matching of acid, alkali and water is common, in precise and ultra-precise industrial cleaning, some metals are washed by water and added with an antirust agent, and most of the metals are required to be made into pure water. In recent years. In parts of China, the water shortage is serious, and the water for cleaning is challenged. In precision industrial cleaning, the production of pure water is expensive. After washing, heating and drying are needed, and a plurality of rinsing stations are added. The energy consumption is large, and the operation cost is generally higher than that of solvent washing; in addition, the waste water containing a large amount of chemical active agents and dirt is directly discharged without treatment. Some of them also carry heavy metals with great toxicity, and seriously pollute the environment.

The cleaning agent (semi-water base type) is composed of high boiling point solvent and activator. Generally contains 5-20% of water, is not easy to burn, and the water content is not properly controlled when the cleaning agent is heated, so that the burning phenomenon can be generated. The semi-aqueous type is stripped off, rather than dissolved, in the hospital. In order to prevent the peeled oil stains from being attached to the object to be cleaned, the cleaning liquid is continuously circulated, and an oil-water separator is added. The semi-water washing is usually good in cleaning effect, but high in operation cost, waste liquid cannot be recycled, the waste liquid is reused, COD (chemical oxygen demand) is high, and waste water treatment is needed.

The cleaning agent (solvent type) means an organic solvent insoluble in water. The solvent is composed of hydrocarbon solvents, halogenated hydrocarbons, alcohol solvents, ether solvents, ketone solvents, ester solvents, phenol solvents and mixed solvents.

The cleaning agent composed of CFC-113 (trichlorotrifluoroethane), ethanol, normal hexane and nitromethane is used in the degreasing technology of Japan, although the cleaning agent composed of the mixed solvents overcomes the defects of flammability and explosiveness, the CFC-113 has anesthesia effect after being contacted for a long time, has irritation to eyes and skin, pollutes water and atmosphere, and has strong destructive power to an ozone layer, ODP (ozone depletion potential value) is 0.9, and GWP (global warming potential value) is 1.551.

The cleaning agent composed of HCFC-141b (monofluorodichloroethane), HCFC-123, methanol and nitromethane is used in the degreasing technology of the United states, the ODP (ozone-destroying potential value) of HFCF-141b in the cleaning agent composed of the mixed solvents is 0.09, the GWP (global warming coefficient value) is 0.195 to replace CFC-113, the damage to the ozone layer is reduced, but the damage to the ozone layer is difficult to recover, and simultaneously the existence of the methanol or the nitromethane causes the solution to have moderate toxicity.

At present, organic solvents such as carbon tetrachloride, fluorine-chlorine hydrocarbons, acetone and the like are generally adopted for cleaning and removing oil from stainless steel pipelines in the field of China aerospace. Carbon tetrachloride has high toxicity, has an anesthetic effect on the central nervous system, and has serious damage to the liver and kidney of a human body; the fluorine-chlorine hydrocarbons have strong destructive power to the atmospheric ozone layer; acetone is volatile and easy to crystallize, and belongs to a controlled chemical product. In the aerospace field, the requirements for degreasing and cleaning various pipe fittings are higher and higher, and residual grease and redundant substances in the pipe fittings can cause great potential safety hazards and influence the whole test and launching tasks.

Disclosure of Invention

Aiming at the technical problems, the invention provides the aerospace precision industrial cleaning agent which has the advantages of high cleaning speed, thorough cleaning, no residue, low cost, mild use conditions, low toxicity and environmental protection.

The technical scheme of the invention is as follows:

the cleaning agent for the aerospace precision industry comprises the following components in percentage by mass:

85-95% of dichloromethane; 0-15% of ethanol; and ethyl acetate 1-15%.

Preferably, the cleaning agent for the precision aerospace industry comprises the following components in percentage by mass:

93-95% of dichloromethane; 1-5% of ethanol; and ethyl acetate 1-5%.

Preferably, the cleaning agent for the aerospace precision industry also comprises a nonionic surfactant.

Preferably, the cleaning agent for the aerospace precision industry consists of the following components in percentage by mass:

93-95% of dichloromethane; 1-5% of ethanol; 1-5% of ethyl acetate; and 2% of nonionic surfactant.

93% of dichloromethane; 3% of ethanol; 2% of ethyl acetate; and 2% of nonionic surfactant.

Preferably, in the cleaning agent for the precision aerospace industry, the nonionic surfactant is any one of castor oil polyoxyethylene ether, octyl phenol polyoxyethylene ether and sorbitol polyoxyethylene ether.

The cleaning agent for the aerospace precision industry has the beneficial effects that:

(1) the cleaning agent has strong reaction, dispersion or dissolution cleaning capability on dirt, can remove the dirt more thoroughly within a limited period of time, and has high dirt cleaning speed and thorough dirt dissolution. ,

(2) the adopted components are cheap and easy to obtain, the cleaning cost is low, and excessive resource consumption is avoided. The cleaning agent has low toxicity to organisms and environment, and the generated waste, waste liquid and waste residue can be treated to meet the requirements of relevant national regulations. The cleaning condition is mild, does not depend on strengthening conditions, and does not need over-high requirements on temperature, pressure and the like. The cleaning agent is nonflammable and explosive, and the cleaning agent is phosphorus-free and environment-friendly and reduces the COD value.

(3) Insoluble substances are not left on the surface of a cleaning object in the cleaning process, new dirt is not generated, a new covering layer harmful to the subsequent process is not formed, the quality of products is not influenced, and foams and peculiar smell influencing the cleaning process and the site sanitation are not generated.

Drawings

FIG. 1 is a graph showing the distribution of solubility parameter SP values of detergents of examples 1 to 7 according to the present invention;

FIG. 2 is a graph showing the surface tension distribution of the cleaning agents of examples 1 to 7 according to the present invention;

FIG. 3 is a density profile of the cleaning agents of examples 1 to 7 according to the present invention;

FIG. 4 is a viscosity profile of the cleaners of examples 1-7 according to the present invention;

FIG. 5 is a boiling point profile of the cleaning agents of examples 1 to 7 according to the present invention;

FIG. 6 is a graph showing the flash point distribution of the cleaning agents of examples 1 to 7 according to the present invention;

FIG. 7 is a KB value distribution graph of the cleaning agents of examples 8 to 19 according to the invention;

FIG. 8 is a graph of the solubility parameter SP values for the detergents of examples 8 to 19 according to the present invention;

FIG. 9 is a surface tension profile of the cleaning agents of examples 8 to 19 according to the present invention;

FIG. 10 is a density profile of the cleaning agents of examples 8 to 19 according to the present invention;

FIG. 11 is a viscosity profile of the cleaners of examples 8-19 according to the invention;

FIG. 12 boiling point profiles of detergents according to examples 8 to 19 of the present invention;

FIG. 13 is a graph of the flash point distribution of the cleaners of examples 8-19 according to the invention;

FIG. 14 is a KB value distribution graph of the cleaning agents of examples 20 to 23 according to the invention;

FIG. 15 is a graph of the solubility parameter SP values for the detergents of examples 20 to 23 according to the present invention;

FIG. 16 is a boiling point profile of the cleaning agents of examples 20 to 23 according to the present invention;

FIG. 17 is a graph showing the flash point distribution of the cleaning agents of examples 20 to 23 according to the present invention;

FIG. 18 is a schematic view of the measurement of surface tension by the U-tube method.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to make the aforementioned objects, features and advantages of the invention more comprehensible.

The invention provides a cleaning agent for aerospace precision industry, which comprises the following components in percentage by mass: 85-95% of dichloromethane; 0-15% of ethanol; and ethyl acetate 1-15%.

In a preferred embodiment, the cleaning agent for the precision aerospace industry comprises the following components in percentage by mass: 93-95% of dichloromethane; 1-5% of ethanol; and ethyl acetate 1-5%.

In a preferred embodiment, the cleaning agent for the aerospace precision industry further comprises a nonionic surfactant.

In a preferred embodiment, the cleaning agent for the aerospace precision industry consists of the following components in percentage by mass: 93-95% of dichloromethane; 1-5% of ethanol; 1-5% of ethyl acetate; and 2% of nonionic surfactant.

In a preferred embodiment, the cleaning agent for the aerospace precision industry consists of the following components in percentage by mass: 93% of dichloromethane; 3% of ethanol; 2% of ethyl acetate; and 2% of nonionic surfactant.

In a preferred embodiment, in the cleaning agent for precision aerospace industry, the nonionic surfactant is any one of castor oil polyoxyethylene ether, octyl phenol polyoxyethylene ether and sorbitol polyoxyethylene ether.

To further illustrate the technical solution of the present invention, the following examples are now provided.

Examples 1 to 7

The formulation of the cleaning agent in examples 1 to 7 is shown in Table 1.

TABLE 1 formulation ratio of each component in cleaning agent in examples 1 to 7

Test experiments were performed on the cleaning agents of examples 1 to 7.

Analysis of (one) KB values

TABLE 2 KB values for cleaning agents from examples 1 to 7

The KB values of examples 1 to 7 are shown in table 1. The KB value is an indicator of the relative solvency of the hydrocarbon solvent, a larger KB value indicates a greater solvency of the solvent, the KB value is not required to be too high for a detergent solution, and the KB value is too high and has a greater solvency.

(II) solubility parameter SP value analysis

The solubility parameter SP values for examples 1-7 are shown in FIG. 1, and it can be seen from FIG. 1 that the overall data is substantially flat. The solubility parameter SP is a physical constant for measuring the compatibility of liquid materials, the closer the solubility parameters of two high polymer materials are, the better the blending effect is, the difference between the two is more than 0.5, and the blending is difficult to be uniform. The metal processing uses a large amount of oil products, and the oil products require good lubricating, rust preventing and cooling performances. Machine oil, diesel oil, kerosene, vaseline, and paraffin are main components of rust preventive oil, lubricating oil, emulsion, lubricating grease, etc.

The engine oil consists of two parts, namely base oil and an additive, wherein the base oil is the main component of the lubricating oil, the basic property of the lubricating oil is determined, and the additive can make up and improve the deficiency of the base oil in performance and is an important part of the lubricating oil.

The U.S. API groups base oils into 5 categories based on the main properties of the base oil composition:

group I is solvent refined base oil, which has higher sulfur content and unsaturated hydrocarbon (mainly aromatic hydrocarbon);

the II is hydrotreated base oil with lower sulfur nitrogen content and aromatic hydrocarbon content;

the III group is mainly hydroisomerized base oil, which has low sulfur and aromatic hydrocarbon content and high viscosity index;

IV type poly-a-olefin synthetic oil base oil;

the engine oil used for the lathe is mainly I-type, and consists of unsaturated hydrocarbons and is mainly aromatic hydrocarbons.

The main component of diesel oil is alkane, cycloalkane or aromatic hydrocarbon containing 10 to 22 carbon atoms.

The kerosene is a high boiling point hydrocarbon mixture with carbon atoms of C11-C17, and contains saturated hydrocarbons as main components, unsaturated hydrocarbons and aromatic hydrocarbons. The solubility parameter SP of the aromatic hydrocarbon is about 5.1-5.4.

(III) surface tension analysis

The surface tension of the cleaning agent (see fig. 2) of each of the above examples is substantially even, and the surface tension of the cleaning agent is slightly higher than that of dichloromethane, and the cleaning agent has small surface tension and strong permeability.

(IV) Density analysis

As shown in FIG. 3, the density of the cleaning agent of each of the above-mentioned embodiments is substantially equal, and the cleaning agent density is a basic characteristic quantity, and the difference with the density of water is within 0.5, so that the requirement of the industrial cleaning agent can be met.

(V) viscosity analysis

As shown in FIG. 4, the viscosity of the cleaning agent of each of the above examples is substantially even, the viscosity of the cleaning agent is slightly higher than that of the groups of 1-12, the lower the viscosity, the better the penetration ability, and the better the cleaning effect of the oil stain.

(VI) boiling point analysis

As shown in FIG. 5, the higher the azeotropic boiling point of the cleaning agent in each of the above examples, the less volatile it is. The dichloromethane has low boiling point and is volatile in summer outdoor environment, and other organic solvents are added into the solvent to form an azeotropic mixture so as to inhibit the volatilization of the dichloromethane under summer outdoor conditions.

(seventh) flash Point analysis

As shown in FIG. 6, the flash point of the cleaning agent of each of the above examples was high. The flash point is a safety index for storage, transportation and use of flammable liquids, and is also an index of volatility of flammable liquids. Flammable liquid with low flash point, high volatility, easy ignition and poor safety. The flash point of the precise cleaning agent solution is higher, so that the fire disaster is avoided, and the safety of the precise cleaning agent solution is ensured.

Example 8 to example 19

The formulation of the example 8 to example 19 cleaners is shown in table 3.

TABLE 3 compounding ratio of each component in example 8 to example 19

The detergents of examples 8 to 19 were tested for their respective properties. Specific test results are shown in fig. 7 to 13, wherein abscissa numbers a1, a2, A3, B1, B2, B3, C1, C2, C3, D1, D2, and D3 in fig. 7 to 13 sequentially represent examples 8 to 19.

Analysis of (one) KB values

As shown in FIG. 7, the KB values of the cleaning agents of examples 8 to 19 theoretically meet the requirements of the precision cleaning agent, the KB value of the precision cleaning agent cannot be too high, and if the composite material is arranged on the surface of the cleaned metal material, the KB value is too high to dissolve the composite material on the surface, so that the cleaned metal material is damaged. When the content of dichloromethane is 93-95% and the content of ethanol and ethyl acetate is 5-7% (namely, example 15, example 16, example 18 and example 19), the KB value of the cleaning agent is optimal.

(II) solubility parameter SP value analysis

As shown in FIG. 8, the solubility parameter SP of the cleaning agent in the examples 8 to 19 is different from that of engine oil, diesel oil and kerosene by less than 0.5, so that the mixing effect is good, and the requirement of a precise cleaning agent is met. When the content of dichloromethane is 93-95% and the content of ethanol and ethyl acetate is 5-7% (namely, example 15, example 16, example 18 and example 19), the solubility parameter SP of the cleaning agent is optimal.

(III) surface tension analysis

As seen from the data in FIG. 9, the surface tension of the cleaning agent is optimal when the content of dichloromethane is 93% -95% and the content of ethanol and ethyl acetate is 5% -7% (i.e. example 15, example 16, example 18 and example 19).

(IV) Density analysis

From the data in FIG. 10, it can be seen that the densities of the cleaning agents of examples 8 to 19 are substantially equal and the overall viscosity is 1.2g/cm³Left and right. Combining other technical parameters, the density of the cleaning agent is optimal when the content of dichloromethane is 93-95% and the content of ethanol and ethyl acetate is 5-7% (namely, example 15, example 16, example 18 and example 19).

(V) viscosity analysis

From the data in fig. 11, it is seen that there is a gradual increase in the viscosity of the cleaning agent from example 14, with the overall viscosity of examples 8 to 19 being around 2 mpa.s. The flash point of the cleaning agent is optimal when the content of dichloromethane is 93-95% and the content of ethanol and ethyl acetate is 5-7% (namely, example 15, example 16, example 18 and example 19).

(VI) boiling point analysis

From the data in fig. 12, it can be seen that the boiling point of the cleaning agent tends to decrease with the increase of the dichloromethane content, but the boiling point of the cleaning agent is optimal when the single component is still higher, the dichloromethane content is 93% -95%, and the ethanol and ethyl acetate content is 5% -7% (i.e. example 15, example 16, example 18, example 19).

(seventh) flash Point analysis

As can be seen from the data in fig. 13, example 14 and example 15 have higher flash points than the other components. The flash point of the cleaning agent is optimal when the content of dichloromethane is 93-95% and the content of ethanol and ethyl acetate is 5-7% (namely, example 15, example 16, example 18 and example 19).

Examples 20 to 23

The formulation of the example 20 to example 23 cleaners is shown in table 4.

Table 4 formulation ratio of each component in example 20 to example 23 detergent

In examples 21 to 23, the nonionic surfactants were each 2% by mass in the detergent, and the dichloromethane, ethanol, and ethyl acetate were 93%, 3%, and 2% by mass in the detergent, respectively.

The nonionic surfactant used:

performance parameters of EL-20: name: castor oil polyoxyethylene ether; appearance: a light yellow liquid; hydroxyl value: 90-100 parts of; pH: 5-7.

OP-10 Performance parameters: name: octylphenol polyoxyethylene ether; appearance: a yellow viscous liquid; hydroxyl value: 83-93; pH: 5-7.

TWEEN-20 Performance parameters: name: sorbitol polyoxyethylene ether; appearance: a light yellow viscous liquid; hydroxyl value: 90-110; pH: 5-7.

The detergents of examples 20 to 23 were tested for their respective properties. The specific test results are shown in fig. 14 to 17, in which abscissa numbers a1, a01, a11, and a21 in fig. 14 to 17 represent examples 20 to 23 in this order.

It can be seen from FIGS. 14-17 that the KB value of the cleaner formulated with EL-20 (i.e., example 21) is slightly less than that of the other three sets of examples. The KB value of the precise cleaning agent cannot be too high, and if the composite material is arranged on the surface of the cleaned metal material, the KB value is too high, so that the composite material on the surface can be dissolved, and the cleaned material can be damaged. The solubility parameter SP of the cleaning agent compounded by adding the EL-20 is equal to that of the cleaning agents of other three groups of embodiments. The boiling point of the cleaning agent compounded by adding the EL-20 is slightly larger than that of the cleaning agents of other three groups of embodiments. The higher the boiling point, the less volatile the detergent solution is during cleaning. The flash point of the cleaning agent added with the EL-20 compound is slightly larger than that of the cleaning agents of other three groups of embodiments, the flash point is higher, the explosion is not easy, and the safety is good.

Thus, the performance of the cleaning agent with EL-20 added (i.e., example 21) is optimized by comparing the KB value, the solubility parameter SP, the boiling point, and the flash point.

Example 24 and comparative example

Cleaning experiments were carried out using the detergents of examples 20 to 23 and a comparative example, the amount of the cleaning agent used was 100g, the amount of the oily soil (engine oil, diesel oil, kerosene) was 20g, and the test object was 10 × 5, 5 × 5cm³A metal container. The comparative example is a cleaning agent compounded by carbon tetrachloride and acetone.

And monitoring the cleaning process by using an SITA oil stain detector to detect the cleanliness of the metal container. Reading mode: percentage values or RFU values (relative fluorescence units), the higher the RFU value, the worse the cleanliness. The results of the washing experiments are shown in Table 5.

Table 5 cleaning test results of examples 20 to 23 and one comparative example

As can be seen from the cleaning results in Table 5, the cleaning effects are sequentially ranked from good to bad as the cleaning agent compounded by adding EL-20 (example 21), the cleaning agent compounded by adding OP-10 (example 22), the cleaning agent compounded by adding TWEEN-20 (example 23), the cleaning agent compounded by not adding a surfactant (example 20), and the cleaning agent compounded by carbon tetrachloride and acetone in the room (comparative example). The oil stain cleaning time is shortest by adding the EL-20 compound cleaning agent; the cleaning time of the cleaning agent added with the surfactant for cleaning oil stains is shorter than that of the cleaning agent without the surfactant, and the cleaning effect of the surfactant in the comparative example is the slowest.

The specific method of each test experiment is as follows:

KB value test

The KB value method is the most commonly used method for measuring the solvency of hydrocarbon solvents, and the larger the KB value, the stronger the solvency.

Preparing a shell rosin-n-butyl alcohol solution:

400g of clean, light white shell rosin is ground to particles of the size of soybean particles, placed in a 3L flask, 2Kg of n-butanol with the boiling point of 116-. Standing the solution for 48h, then performing suction filtration by using a Buchner funnel and double-layer medium-speed qualitative filter paper, discarding residues, and taking clear liquid for later use.

The volume V of toluene used is recorded at 25. + -. 1 ℃ when a solution of kauri-butanol (20. + -. 0.1 g) is titrated with toluene to give a defined turbidity (titration end point)₁。

Under the same conditions, using n-heptaneThe volume of the mixed solution used when the mixed solution was dropped into toluene (75%: 25%) was denoted as V₂。

Titration of the n-butanol solution (20. + -. 0.1) g of shell rosin with the solvent to be tested, and the sample volume V₃。

KB＝65*V₃-V₂/V₁-V₂+40 (1)

The judgment of the turbidity degree needs to be consistent as much as possible during titration, the turbidity degree card is observed from top to bottom through the solution in the bottle, the titration is carried out until the printed symbol on the card begins to be fuzzy and cannot be cleared and observed, and the titration end point is positioned when the turbidity degree of the symbol can be read.

(II) solubility parameter SP test

Turbidity titration method

In binary miscible systems, as long as a certain polymer has a fixed solubility parameter_pWithin the range of values for two miscible solvents, we have the possibility to adjust the solubility parameters of these two miscible mixed solvents so that_smValue sum_pVery closely, therefore, we only need to make two mutual solvents into a mixed solvent according to a certain percentage, and the solubility parameter of the mixed solvent_smCan be approximately expressed as:

sm＝Φ₁ ₁+Φ₂ ₂(2)

in the formula: phi₁、Φ₂The volume fractions of component 1 and component 2 in the solution are indicated, respectively.

Turbidity titration is a process in which the polymer to be tested is dissolved in a solvent and titrated with a precipitant, which is miscible with the solvent, until the solution begins to develop turbidity. Thus, we can obtain the solubility parameter of the mixed solvent at the cloud point_smThe value is obtained.

The polymer is dissolved in a binary mutual solvent system, and the solubility parameter of the system is allowed to have a range. In this experiment, two precipitants with different solubility parameters are selected to titrate the polymer solution, so as to obtain the upper limit and the lower limit of the parameters of the mixed solvent for dissolving the polymer, and then the average value is taken, namely the polymer_pThe value is obtained.

Here, the_mhAnd_mlthe precipitant, which is high and low in solubility parameter, titrates the polymer solution, and the solubility parameter of the mixed solvent is at the cloud point.

(1) Selection of solvents and precipitating agents

Firstly, determining the solubility parameter of a cleaning agent sample to be detected_pThe range of (1). Taking a small amount of sample, carrying out dissolution test in different solvents, heating the cleaning agent to be tested and the solvent together at room temperature if the sample is insoluble or slowly dissolved, and cooling the hot solution to room temperature so as not to precipitate and then to be considered as soluble. From which the appropriate solvent and precipitant are selected.

(2) Preparing polymer solution according to selected solvent

About 0.2 g of a sample of the detergent to be tested was weighed and dissolved in 25ml of a solvent (chloroform was used as the solvent). 5ml (or 10ml) of the solution are pipetted and placed in a test tube, and the polymer solution is titrated first with n-pentane, causing precipitation. The tube was shaken to dissolve the precipitate. The n-pentane is continuously dropped into the mixture, and the precipitate is gradually difficult to dissolve by shaking. Titration was performed until the precipitate appeared to be just insoluble and the volume of n-pentane used was recorded. Then, the same procedure was performed with n-pentane by titration with methanol, and the volume of methanol used was recorded.

(3) About 0.1 g and about 0.05 g of the cleaning agent sample to be detected are respectively weighed and dissolved in 25ml of solvent, and titration is carried out by the same operation.

Formula (2) calculating solubility parameter of mixed solvent_mhAnd_mlequation (3) calculating the solubility parameter of the mixed solvent_p。

(III) surface tension test

The water level of the purified water in the glass tube is concave as shown in fig. 18. The liquid is concave in the U-shaped pipe and can be approximately regarded as the radius r₁、r₂The hemispherical surface of (a). If p is_A、p_BPressure at A, B points below the water surface, p₀At atmospheric pressure, the water surface equilibrium conditions are:

in the formula, theta is the contact angle of the liquid and the glass tube, and gamma is the surface tension of the liquid.

With clean glass and water, θ is 0, then:

if Δ p is the difference in atmospheric pressure between the lowest points of the two concave surfaces, p_A＝p_CAnd then:

Δp＝p_B-p_A＝ρgh (8)

where h is the height difference between the lowest points A, B of the two liquid levels.

The combination of the formulas (6), (7) and (8) can obtain:

the above formula shows that only the inner diameters d of two glass tubes are measured₁、d₂And the height difference h between the two liquid levels, the surface tension coefficient of the liquid can be obtained.

(IV) Density test

The mass of a substance contained in a unit volume is referred to as the density of the substance. The density of the liquid can be accurately measured by a pycnometer method.

The calculation formula is as follows: ρ ═ ρ_{Water t}.(g₃—g₁)}/(g₂—g₁) (10)

Where rho-density of the liquid to be measured

ρ_{Water t}Density of water at a given temperature

g₁Weight of pycnometer

g₂-the sum of the weight of the bottle and the weight of the water charged

g₃-the sum of the weight of the pycnometer and the weight of the ethanol charged

(V) viscosity measurement

The viscosity of the liquid is generally expressed by a viscosity coefficient η, and when the viscosity of the liquid is measured by a capillary method, the viscosity coefficient (viscosity for short) can be calculated by a poisson formula.

η＝πPtr⁴/8VL (11)

V-volume of liquid flowing through the capillary at time t

P-pressure difference across capillary

r-radius of tube

L-length of tube

In the CGS system, the unit of viscosity is poise (P), 1P ═ 1drn.s.cm^-1In the international system of units, viscosity is (PaS), and 1P is 0.1PaS, and it is difficult to measure absolute viscosity of a liquid according to the above formula, but it is easy to measure relative viscosity of a liquid to a certain liquid (known viscosity).

Two kinds of liquid flow through the same capillary under the gravity of the liquid, and the outflow volumes are equal, then

η₁＝πP1t1r⁴/8VL η₂＝πP₂t₂r⁴/8VL

Where P is rho gh

h-liquid level difference for driving liquid to flow

Rho-liquid density

g-acceleration of gravity

If the volume of the sample is constant each time, h can be kept the same in the test, so η₁/η₂＝ρ₁t₁/ρ₂t₂Knowing the viscosity of the standard liquids and their density, the viscosity of the measured liquid can be calculated as above.

(VI) boiling point test

The liquid to be tested was added to the distillation flask via a funnel and 2-3 grains of zeolite were added. The condensed water is switched on to start heating, and the temperature rises slowly.

When the steam reflux interface rises to the mercury bulb part of the thermometer, the temperature rises sharply, the temperature is controlled, the steam condensate is attached to the mercury bulb of the thermometer, the gas-liquid two-phase balance is kept, and the temperature is the boiling point of the distillate at the moment.

The distillation rate was controlled at 1-2 drops/s and the temperature at which the first drop of distillate dropped into the receiver and the liquid was immediately distilled off, i.e. the boiling point of the material, was recorded.

(VII) flash Point test

Heating a crucible to gradually raise the temperature of a sample, and adjusting the heating speed when the temperature of the sample reaches 60 ℃ before an expected flash point; the temperature rise rate was controlled to be 4 ℃. + -. 1 ℃ per minute at 40 ℃ before the sample temperature reached the flash point.

Secondly, when the temperature of the sample in the ignition test reaches 10 ℃ before the expected flash point, the flame of the igniter is placed 10-14 mm away from the liquid level of the sample, and moves linearly along the inner diameter of the crucible in the horizontal direction, and the time for moving from one side of the crucible to the other side is 2-3 s. The ignition test should be repeated every 2 c rise in the specimen temperature.

Third, when the blue flame first appears above the liquid level of the flash point sample, the temperature is immediately read from the thermometer, and the atmospheric pressure is recorded as the measurement result of the flash point.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications without departing from the spirit and scope of the present invention.

Claims

1. The cleaning agent for aerospace precision industry is characterized by being used for cleaning oil stains on the surface of a metal material,

the adhesive consists of the following components in percentage by mass:

93% of dichloromethane; 3% of ethanol; 2% of ethyl acetate; and 2% of a nonionic surfactant; the nonionic surfactant is castor oil polyoxyethylene ether.