WO2013070913A1

WO2013070913A1 - Rust inhibiting lubricant

Info

Publication number: WO2013070913A1
Application number: PCT/US2012/064147
Authority: WO
Inventors: Ying Wei Xie; Matthew T. Scholz; Kai Qiu
Original assignee: 3M Innovative Properties Company
Priority date: 2011-11-11
Filing date: 2012-11-08
Publication date: 2013-05-16
Also published as: CN103087811A; IN2014CN03450A; CN103087811B

Abstract

The present invention provides a rust inhibiting lubricant. Based on the total weight of the rust inhibiting lubricant, the rust inhibiting lubricant comprises: (a) from 5% to 45% of base oil, wherein the base oil is one or more substances selected from the following group: polyalkelene glycol, fatty glyceride and propanetriol; (b) from 0.1% to 15% of corrosion inhibitor, wherein the corrosion inhibitor may be one or more substances selected from the following group: organic poly(carboxylic acid), organic polycarboxylate salt and alkyl amine; (c) from 0.05% to 10% of anti-corrosion agent, wherein the anti-corrosion agent may be one or more substances selected from the following group: benzoic acid anti-corrosion agents and isothiazoline anti-corrosion agents; and (d) from 30% to 90% of water.

Description

RUST INHIBITING LUBRICANT

FIELD

The present disclosure relates to a rust inhibiting lubricant, and particularly relates to a rust inhibiting lubricant for medical instruments, and further relates to a method for lubricating medical instruments.

BACKGROUND

In daily operation, hospitals extensively use stainless steel medical instruments or other metallic medical instruments, such as surgical scissors, surgical kidney basins, and stainless steel tweezers. Contact of these metallic medical instruments with blood, body fluids, and electrolytes such as chlorine- and iodine-containing disinfectant and saline, will accelerate corrosion of the instruments, causing rusting of the instruments and malfunction of their pivots. These problems increase operating costs of the hospitals and increase infection risks of patients. In order to extend service life of the metallic medical instruments and reduce hospital expenditures and costs, many hospitals use strong acidic rust removers for rust removal treatment of rusty instruments so that they can reuse the instruments. However, the strong acidic rust remover also causes corrosion to the metals while removing rusts, thus resulting in secondary corrosion of the instruments.

In order to reduce infection risks in hospitals and extend service life of the metallic medical instruments and help hospitals reduce costs, a lot of hospitals will carry out lubricating antirust treatment to the metallic medical instruments after cleaning, based on infection control specifications and requirements. Rust inhibiting lubricant for the medical instruments can be conveniently adhered to the surfaces of the metallic medical instruments by an automatic cleaning machine or by manual soaking to form a protective film. The protective film can lubricate pivots of the medical instruments and prevent the metallic medical instruments from contacting oxygen in the air, thus generating rust prevention and lubrication effects. Moreover, the protective film is a water-soluble substance and can be penetrated through by high-pressure steam.

Rust inhibiting lubricants of prior art, including water-based lubricants and oil-based lubricants, are mainly used in metal processing industries and for rust prevention of some industrial metallic reactors. For example, US005538654A provides an environmentally friendly oil-based lubricant used for food processing equipment by using a modified vegetable oil and an emulsifier system. US20040241309A1 provides a food-grade lubricant also used for the food industry by using triglyceride as base oil.

In the health care industry, rust inhibiting lubricants of prior art are mainly used for lubrication of catheters, cannulae and some puncture needles. There are very few reports on lubrication of metallic medical instruments. US20100048759 provides a lubricant for surgical instruments, which is a water-soluble lubricant containing glycerin, polyethylene glycol and water, and is substantially surfactant- free. However, the lubricant is mainly used for manual lubrication, not suitable for automatic cleaning machines. Therefore, in view of practical applications in the health care industry, it is necessary to provide a new rust inhibiting lubricant for metallic medical instruments, which can not only be used for manual lubrication, but also be used for medical cleaning machines. SUMMARY

One of the objectives of the present disclosure is to provide a rust inhibiting lubricant. According to one aspect of the present disclosure, based on the total weight of the rust inhibiting lubricant, the rust inhibiting lubricant comprises:

(a) from 5% to 45% of base oil, and the base oil is one or more substances selected from the following group: polyalkelene glycol, fatty glyceride and propanetriol;

(b) from 0.1% to 15% of corrosion inhibitor;

(c) from 0.05% to 10% of anti-corrosion agent; and

(d) from 30% to 90% of water.

Another objective of the present disclosure is to provide a method for lubricating medical instruments. According to one embodiment of the present disclosure, the method comprises steps of treating medical instruments with the rust inhibiting lubricant provided in the present invention.

The rust inhibiting lubricant provided in the present disclosure is mainly used for lubricating the surfaces and pivots of the metallic medical instruments to ensure the medical instruments can be used maneuverably. Moreover, the rust inhibiting lubricant can form a layer of a rust-proof film on the surfaces of the metallic medical instruments to prevent the metallic medical instruments from corrosion and rusting, thus extending service life of the metallic medical instruments.

In some embodiments, the rust inhibiting lubricant of the present disclosure exhibits the following advantages:

1. As a concentrated lubricant, it can be diluted in high ratios and can be used for lubrication with machine and by manual soaking after dilution.

2. It contains corrosion inhibiting ingredients, which can effectively prevent oxidation-reduction on metal surfaces, and alleviate corrosion of protein and electrolytic substances to metal.

3. There are environmentally safe formulas available, which are not irritating to skins.

4. There are water soluble low viscosity formulas available, which are emulsifier-free, with less residual substances left on the surfaces of the instruments. DESCRIPTION OF DRAWINGS

Figure 1 is a comparison of foam level test results of various lubricants at the time of 0, 10, 20 and 30 sec at 60°C.

Figure 2 is a comparison of foam level test results of various lubricants at the time of 0, 10, 20 and 30 sec at 25°C.

Figure 3 is a comparison of lubricating performance test results between an example of the present invention and the comparison example.

Embodiments

The present disclosure provides a highly concentrated, durably stable, aqueous, rust inhibiting lubricant. The rust inhibiting lubricant provided in the present disclosure can lubricate surfaces and pivots of the metallic medical instruments, and meanwhile form a layer of rust-proof film on the surfaces of the metallic medical instruments to prevent the medical instruments from rusting too quickly, thus extending service life of the medical instruments.

Generally, a water soluble base oil suitable for food apparatus or medical instruments is used to substitute conventional mineral oil as a lubricating ingredient for the rust inhibiting lubricant of the present invention to obtain a transparent aqueous rust inhibiting lubricant without an emulsifier.

The rust inhibiting lubricant is physically stable. The term "physically stable" herein means that the rust inhibiting lubricant will not change significantly at room temperature and therefore become different from its initial state in at least 3 months due to obvious precipitation, crystallization, phase separation, and the like.

All the contents and percentages used in the present invention are based on weight unless otherwise specified.

Cleaning and lubricating procedures generally required in hospitals may be carried out by machine or manually. Requirement for the lubricants can be different depending on different operating methods.

A general procedure for cleaning with automatic cleaning machine is as follows: first of all, a pre-cleaning process of a medical instrument is carried out at room temperature, and then temperature is raised to, for example, 45°C, and then cleaning is carried out after a detergent is added. After the cleaning is carried out once or twice, temperature is further raised to, for example, above 45°C, preferably above 60°C but below 85°C. Preferably, a lubricant is added at a temperature below 75°C for a final cleaning, and then the medical instrument is dried. Conventional automatic cleaning machines in the art may be used. Their examples include but are not limited to products of Getinge, Belimed, Xinhua and other brands.

Manual cleaning process may be carried out in two ways: (1) the lubricant is diluted with water in a vessel, and a medical instrument is immersed in the vessel for a period of time, for example, 5 min, and then the medical instrument is taken out and dried; or (2) The diluted lubricant is sprayed directly onto pivots of the medical instrument. Manual cleaning has no special requirement for operating temperatures and is normally carried out at ambient temperatures.

In some embodiments, the rust inhibiting lubricant has low foaming ability, and withstands high temperatures, therefore is suitable for lubricating with machines. Meanwhile, the rust inhibiting lubricant is a water-based lubricant and can be easily diluted with water; meanwhile it still keeps good stability after dilution. Therefore, it is also suitable for manual lubricating. When the rust inhibiting lubricant is diluted with water, dilution ratio by weight may vary in a range from adding 1 part of rust inhibiting lubricant into 10 parts of water to adding 1 part of rust inhibiting lubricant into 600 part of water. Preferably, when used for automatic cleaning machine, 1 part of lubricant can be diluted with 200 to 600 parts of water by weight; when used for manual cleaning, 1 part of lubricant can be diluted with 10 to 20 parts of water by weight. Since the automatic cleaning machine is operated in a spraying manner, the lubricant can be sprayed onto pivots of the medical instruments; therefore the dilution ratio is relatively high. However, since manual lubricating is carried out by soaking, and the lubricant will normally be used for a whole day after dilution and relatively more medical instruments will be soaked, the dilution ratio is relatively low.

Major ingredients of the rust inhibiting lubricant comprise base oil, corrosion inhibitor, anti-corrosion agent and solvent. The rust inhibiting lubricant may also comprise one or more anti-foaming agents, solubilizing agents, thickening agents and chelating agents.

In some embodiments, the base oil may be oil or a mixture of several types of oils. The selected base oil is well compatible with human bodies, and is environmentally friendly and easy to biodegrade. All of the selected base oils are water soluble, and may be esters, ethers or amines and the like. The base oil may contain one or more polyethylene glycol (PEG) or polyglyceryl groups in its structure. The base oil is preferably polyalkelene glycol, fatty glyceride, propanetriol and the like.

In some embodiments, weight percentage of the base oil in a rust inhibiting lubricant is from 5% to 45%, preferably from 5% to 40%, more preferably from 10% to 35%, even more preferably from 10% to 30%, and most preferably from 15 to 25% based on total weight of the rust inhibiting lubricant.

In some embodiments, polyalkelene glycol may be selected as the base oil. The polyalkelene glycol may be polyalkelene glycol homopolymer, polyalkelene glycol monoether, polyalkelene glycol diether, polyalkelene glycol co-polymer, esters of polyalkelene glycol and the like. The alkylene glycol may be ethylene oxide, propylene oxide and the like. Preferably, a non-limiting example of the polyalkelene glycol is a block co-polymer of ethylene oxide and propylene oxide. There are no particular restrictions on molecular weight of polyalkelene glycol. It is generally from 800 to 13,000g/mol, more preferably from 1,000 to 4,000g/mol, most preferably from 1,200 to 2,000g/ml. Preferably, 1% aqueous solution of the polyalkelene glycol has a cloud point range of 50°C to 70°C. The polyalkelene glycol is an FDA approved substance. Examples of commercially available polyalkelene glycol that can be used include: UCON 50-HB-5100, UCON 50-HB-660, UCON 50-HB-3520 and UCON 75-H-450 manufactured by Dow Chemicals, and PLURASAFE® POLYGLYCOLS WS-660, WS-2000, WS-3520 and WS-5100 manufactured by BASF Auxiliary Chemicals Co., Ltd., and Hydramol™ PGPL manufactured by Lubrizol, and the like.

In some embodiments, weight percentage of polyalkelene glycol in a rust inhibiting lubricant is from 3% to 20%, preferably from 3% to 15% based on total weight of the rust inhibiting lubricant.

In some embodiments, fatty glyceride may be selected as the base oil. The fatty glyceride may be a long chain fatty glyceride. The term "long chain fatty acid" refers to fatty acids containing from 6 to 20 carbon atoms, preferably from 6 to 12 carbon atoms. Their examples include but are not limited to hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, and the like. The fatty glyceride is an ester of glycerin formed with one or more above acids or a mixture thereof, or a polyglycerol ester, such as caprylic/capric triglyceride, polyglyceryl-3 laurate and the like. Examples of commercially available fatty glyceride that can be used include: Hydramol™ TGL ester and the like manufactured by Lubrizol.

In some embodiments, weight percentage of fatty glyceride in a rust inhibiting lubricant is from 5% to 30%, preferably from 10% to 20% based on total weight of the rust inhibiting lubricant.

In some embodiments, propanetriol may be selected as the base oil. In some embodiments, weight percentage of propanediol in a rust inhibiting lubricant is from 5% to 30%, preferably from 10% to 20% based on total weight of the rust inhibiting lubricant.

The rust inhibiting lubricant contains a corrosion inhibitor. When a metal is lubricated, a rust-proof film will be formed on the surfaces of the metallic medical instruments. The rust-proof film adhered to the surfaces of the medical instruments can prevent the metallic medical instruments from contacting with oxygen in the air, thus achieving effects of rust prevention.

In some embodiments, the corrosion inhibitor includes an organic poly(carboxylic acid), an organic polycarboxylate salt, or an alkyl amine. Preferred corrosion inhibitor is nitrogen-containing organic compounds. Their examples include nitrogen-containing organic poly(carboxylic acid), triethanolamine, monoethanolamine, aniline, pyridine, quinoline, diethylamine, cyclohexylamine, thiourea, thiourea derivatives and the like. There are no particular restrictions on molecular weight of organic poly(carboxylic acids) and organic polycarboxylate salts used as a corrosion inhibitor. The molecular weight may be in a range of from 210 to 800g/mol, preferably from 339 to 760 g/mol, more preferably from 468 to 580g/mol. Examples of the organic poly(carboxylic acids) and organic polycarboxylate salts include but are not limited to 2,4,6-(l,3,5-triazine)-organic poly(carboxylic acid), and their salts formed with alkaline metal, alkaline earth metal and the like, such as 2,4,6-(l,3,5-triazine)-organic poly(sodium carboxylate) .

In some embodiments, weight percentage of the corrosion inhibitor in a rust inhibiting lubricant is from 0.1% to 15%, preferably from 0.1% to 10%, more preferably from 0.1% to 6%, even more preferably from 0.2% to 4%, most preferably from 1% to 3% based on total weight of the rust inhibiting lubricant.

Normally, there are no particular restrictions on selection of the anti-corrosion agents. They may include one or more anti-corrosion agents of benzoic acids or anti-corrosion agents of isothiazo lines, such as 5-chloro-2-methyl-4-isothiazolin-3-one, sodium benzoate and the like.

In some embodiments, weight percentage of the anti-corrosion agent in a rust inhibiting lubricant is from 0.05% to 10%, preferably from 0.05% to 5%, more preferably from 0.05% to 2%, and most preferably from 0.1% to 1% based on total weight of the rust inhibiting lubricant.

In the present invention, water is used as a solvent. Weight percentage of water in a rust inhibiting lubricant is from 30% to 90%, preferably from 35% to 85%, more preferably from 40% to 85%, and most preferably from 50% to 80% based on total weight of the rust inhibiting lubricant.

In order to eliminate initial foam in the lubricant oil, an anti-foaming agent may be added to the rust inhibiting lubricant, and the anti-foaming agent can effectively reduce the foam at room temperature. Anti-foaming agents that can be used include one or more epoxy polyvinyl ethers, siloxanes or polyalkelene glycols (when temperature is higher than the cloud point of polyalkelene glycol, polyalkelene glycol can be used as the anti-foaming agent). Examples of commercially available anti-foaming agents include: Surfynol MD20, Surfynol DF-75 and Surfynol DF-110 manufactured by Air Products and Chemicals, Dow Corning DC544 and Dow Corning DB-100 manufactured by Dow Corning.

In some embodiments, weight percentage of the anti-foaming agent in a rust inhibiting lubricant is from 0.01% to 4%, preferably from 0.05% to 2% based on the total weight of the rust inhibiting lubricant.

In order to keep the formulations stable and reduce initial foam, a solubilizing agent can be added to the rust inhibiting lubricant. Solubilizing agents that can be used include ionic surfactants, non-ionic surfactants and alcoholic surfactants and the like, such as one or more of solubilizing agents selected from ionic sulfonate, alkyl amine, ammonium salt, isopropanol or ethanol, such as secondary alkyl sodium sulfonate, alkyl dimethyl ammonium chloride and the like. Examples of commercially available solubilizing agents include: Genaminox OC (manufactured by Clariant, octyldimethylamine oxide, CAS No. 9014-85-1), Surfynol 465 (manufactured by Air Products and Chemicals, ethoxylated diol). The solubilizing agent can also be used to resolve anti-foaming agent. Preferably, ethanol is used in combination with other solubilizing agents.

In some embodiments, weight percentage of the solubilizing agent in a rust inhibiting lubricant is from 0.1% to 40%, preferably from 2% to 30%, more preferably from 5% to 15% based on total weight of the rust inhibiting lubricant.

The rust inhibiting lubricant may also contain a thickening agent. The thickening agent can help improve fluidity of the rust inhibiting lubricant and generate wetting effect. Normally, there are no particular restrictions on selection of the thickening agent. It may include one or more thickening agents selected from polyvinyl alcohol, water soluble cellulose, derivatives of the water soluble cellulose, polyvinyl pyrrolidone. The derivatives of the water soluble cellulose include but are not limited to carboxyalkylated or hydroxyalkylated cellulose, such as carboxymethyl cellulose, carboxyethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethylpropyl cellulose and the like. In some embodiments, weight percentage of the thickening agent in a rust inhibiting lubricant is from 0.01% to 2%, preferably from 0.05% to 0.5% based on the total weight of the rust inhibiting lubricant.

The rust inhibiting lubricant may also contain a chelating agent. The chelating agent has a function of inhibiting fouling formation, and chelating calcium and magnesium ions in water, and softening hard water. The chelating agent may include one or more compounds selected from aminocarboxylic acid, aminocarboxylate salt, organic phosphinic acid, organic phosphonate, such as EDTA, EDTA-2Na, EDTA-4Na, methylnitrilotriacetic acid, DTPMP, DTPMP-Na, DTPMP-2Na and the like.

In some embodiments, weight percentage of the chelating agent in a rust inhibiting lubricant is from 0.1% to 6%, preferably from 0.1% to 3%, more preferably from 0.1% to 1% based on total weight of the rust inhibiting lubricant.

EXAMPLES

A. foam level test

Since the lubricant will be used in automatic cleaning machines, a formulation containing low foam ingredient is preferably selected. A foam level test (STM 100) is carried out for screening the base oil.

1) A 5% oil solution is diluted with distilled water having temperature of 25°C or 60°C in a ratio of

1 :200; 2) The diluted solution is placed in a beaker and initial height of the solution is recorded (corresponding to its volume marked as mL, with a suitable final volume of 500 mL);

3) The solution is agitated at a high speed for 20 sec in an agitating machine (Philips Comfort);

4) Agitation is stopped and foam height of the solution is recorded at 0, 10, 20 and 30 sec;

5) The foam height is calculated:

Foam height = total height at the time of recording - initial solution height.

If the foam height keeps lower than 50 mL in a period of 20 sec, the base oil is preferred.

Table 1 shows the base oil evaluated in the present invention. Ruhof lubricant is a commercially available lubricant for medical instruments and used as a control.

Table 1 Base oil used in the foam level test

Since lubricant is added at temperatures above 60°C during operation of the automatic cleaning machine, foam level of various oils is tested first at 60°C. Figure 1 shows results of the foam level test at 60°C. It can be seen from the figure that foam height for all the samples 2 to 8 is lower than 50 mL in a period of 20 sec.

The operation of the automatic cleaning machine also includes a pre-cleaning process. Since the pre-cleaning is carried out at room temperature (25°C), it is necessary to control foam level during the pre-cleaning at 25°C. Figure 2 shows the test results at 25°C. It can be seen from the figure that foam height for samples 2, 3 and 8 is lower than 50 mL in a period of 20 sec.

It can be seen from the above tests that more preferred samples used as the base oil in the present invention are UCON 50-HB-5100, UCON 50-HB-660 and glycerin. B. Example and comparison example

All contents and percentages are based on weight.

Ingredients are mixed according to the formula in the table below to prepare a rust inhibiting lubricant. All the raw materials used in the examples are commercially available. All the chemicals with no manufacturer indicated are commercially available conventional chemical materials.

Comparison example: another commercially available lubricant (Ruhof lubricant for medical instruments, an emulsion type of lubricant).

Example 1 :

Example 2:

Ingredient Function Manufacturer Content

Polyalkelene glycol base oil Dow Chemicals 5% UCON 50-HB-5100

Caprylic/capric triglyceride base oil 10%

Triethanolamine corrosion inhibitor 1%

EDTA-2Na chelating agent 1%

Sodium benzoate anti-corrosion agent 0.1%

Surfynol MD-20 anti-foaming agent Air Products and 1%

Chemicals

xylenesulfonate solubilizing agent 10%

Hydroxymethyl cellulose thickening agent 0.1%

Deionized water 71.8% Appearance Transparent, stable

Example 3 :

Example 4:

Example 5:

Surfynol MD-20 anti-foaming agent Air Products and 2%

Chemicals

Xylenesulfonate solubilizing agent 40%

Polyvinyl pyrrolidone thickening agent 0.1%

Deionized water 30.7 %

Appearance Transparent, stable

Example 6:

Example 7:

Example 8:

Example 9:

C. Evaluation method for corrosion preventing effects

1. The rust inhibiting lubricant is diluted with pure water according to a required dilution ratio;

2. The diluted solution of rust inhibiting lubricant is heated to 90°C;

3. A piece of polished tinplate is placed in the 90°C diluted solution;

4. The diluted solution is heated at 90°C for 30 min;

5. The tinplate is taken out, thoroughly washed and dried;

6. Color changes of the tinplate are inspected.

In tests of other commercially available products (Ruhof lubricant), color of the tinplate is turned yellow, indicating occurrence of rusting. In the test of Example 7 of the present invention, the tinplate still keeps its original color, indicating that the lubricant has good rust prevention performance.

D. Lubricating performance test A lubricating performance test is carried out according to GB/T 3142-1982 as follows:

1. An oil bath is washed with absolute ethanol and placed in a ventilation cabinet;

2. 10 mL of test solution is poured into the clean oil bath to be used;

3. The oil bath is carefully placed under an abrasion shaft, and part of the abrasion shaft is dipped in the test solution, and the oil bath is fixed with a supporting rack;

4. A steel cylinder is cleaned with absolute ethanol and placed in the ventilation cabinet. After being dried completely, the steel cylinder is measured with a vernier caliper and its diameter is recorded as D 1. Then the steel cylinder is fixed on a press bar with screws;

5. Balance screws are adjusted so that both the press bar and weighing pan are in a horizontal position. According to test requirement, balance weight with different mass can be added on the weighing pan. Result is recorded as blank when no balance weight is added;

6. Abrasion testing machine is started and diameter D2 of the abrasion steel cylinder is measured after a certain period of time. Wear of the steel cylinder is calculated;

7. Calculation formula: Dl - D2.

The test results are shown in Figure 3. The less the wear, the better the lubricating performance it indicates. The rust inhibiting lubricant of the present invention has lubricating effect equivalent to that of the comparison example (Ruhof lubricant).

E. Sterilization penetration test

Normally, medical instruments need to be sterilized after cleaning and lubricating. After lubricating, a layer of oil film is left on surfaces of the medical instruments. In order to determine if the oil film can be penetrated without affecting sterilization, a sterilization penetration test is carried out.

BI #1292 (3M biological indicator) is used for this test.

1) The biological indicator #1292 is immersed in a lubricant sample;

2) The biological indicator #1292 is sterilized with steam at 132°C for 8 min;

3) The biological indicator #1292 is incubated and readout is recorded.

The rust inhibiting lubricant oils as shown in the examples of the present invention is used. Control result before the sterilization is positive, but the result obtained with incubation after the sterilization is negative. The test results indicate that the lubricant oil film doesn't block steam penetration.

F. Oil stain test

A medical tray is lubricated in an automatic cleaning machine, and then oil stain left on surfaces of the medical tray is visually inspected. Results show that none of the lubricants of the embodiments leaves too much oil stain on the surfaces of the medical tray.

It can be seen from the above test results that the aqueous rust inhibiting lubricant of the present disclosure is physically stable. Compared with the emulsion type lubricant of the comparison example, this product has equivalent lubricating effects. Since the rust inhibiting lubricant of the present invention contains a corrosion inhibitor, it can effectively prevent oxidation-reduction reaction on metal surfaces, and alleviate corrosion of protein and electrolytic substances to metal, and generate better rust preventing effects. Since the product can be diluted with water in various ratios, lubrication can be performed not only with a medical cleaning machine but also manually. The rust inhibiting lubricant has water soluble low viscosity formulas, which do not contain an emulsifier, with less residual substances being left on the surfaces of the instruments.

Claims

CLAIMS What is claimed is:

1. A rust inhibiting lubricant, wherein based on the total weight of the rust inhibiting lubricant, the rust inhibiting lubricant comprises:

(a) from 5% to 45% of base oil, wherein the base oil is one or more substances selected from the following group: polyalkelene glycol, fatty glyceride and propanetriol;

(b) from 0.1% to 15% of corrosion inhibitor;

(c) from 0.05% to 10% of anti-corrosion agent; and

(d) from 30% to 90% of water.

2. The rust inhibiting lubricant according to claim 1 , wherein the corrosion inhibitor is one or more substances selected from the group consisting of: organic poly(carboxylic acid), organic polycarboxylate salt and alkyl amine.

3. The rust inhibiting lubricant according to claim 1, wherein the corrosion inhibitor is a nitrogen-containing organic compound.

4. The rust inhibiting lubricant according to claim 1, wherein the anti-corrosion agent is one or more substances selected from the group consisting of: benzoic acid anti-corrosion agents and isothiazoline anti-corrosion agents.

5. The rust inhibiting lubricant according to claim 1, wherein the rust inhibiting lubricant contains from 3% to 20% of polyalkelene glycol based on the total weight of the rust inhibiting lubricant.

6. The rust inhibiting lubricant according to claim 5, wherein a 1% aqueous solution of the polyalkelene glycol has a cloud point range of 50°C to 70°C.

7. The rust inhibiting lubricant according to claim 1, wherein the rust inhibiting lubricant contains from 5% to 20% of fatty glyceride based on the total weight of the rust inhibiting lubricant.

8. The rust inhibiting lubricant according to claim 1, wherein the rust inhibiting lubricant contains from 5% to 20% of propanetriol based on the total weight of the rust inhibiting lubricant.

9. The rust inhibiting lubricant according to claim 1, wherein the rust inhibiting lubricant further contains an additive, wherein the additive is one or more substances selected from the group consisting of: anti-foaming agent, solubilizing agent, thickening agent and chelating agent.

10. The rust inhibiting lubricant according to claim 9, wherein the anti-foaming agent is one or more substances selected from the group consisting of: epoxy polyvinyl ether, siloxane and polyalkelene glycol, wherein the content of the anti-foaming agent is from 0.01% to 4% based on the total weight of the rust inhibiting lubricant.

11. The rust inhibiting lubricant according to claim 9, wherein the solubilizing agent is one or more substances selected from the group consisting of: ionic surfactants, non-ionic surfactants and alcoholic surfactants, wherein the content of the solubilizing agent is from 0.1% to 40% based on the total weight of the rust inhibiting lubricant.

12. The rust inhibiting lubricant according to claim 9, wherein the thickening agent is one or more substances selected from the group consisting of: polyvinyl alcohol, water soluble cellulose, derivatives of water soluble cellulose and polyvinyl pyrrolidone, wherein the content of the thickening agent is from 0.01% to 2% based on the total weight of the rust inhibiting lubricant.

13. The rust inhibiting lubricant according to claim 9, wherein the chelating agent is one or more substances selected from the group consisting of: aminocarboxylic acid, aminocarboxylate salt, organic phosphinic acid, organicphosphonate salt, wherein the content of the chelating agent is from 0.1% to 6% based on the total weight of the rust inhibiting lubricant.

14. The rust inhibiting lubricant according to claim 1, wherein the rust inhibiting lubricant is diluted with water in a ratio of from 1 : 10 to 1 : 600 by weight.

15. A method for lubricating medical instruments, characterized in that the method comprises steps of treating medical instruments with the rust inhibiting lubricant according to any one of claims from 1 to 14.

16. The method according to claim 15, characterized in that the steps of treating medical instruments with the rust inhibiting lubricant are performed with a medical cleaning machine or manually.

17. The method according to claim 16, characterized in that the steps of treating medical instruments with the rust inhibiting lubricant are performed with a medical cleaning machine, wherein the rust inhibiting lubricant is diluted with water in a ratio of from 1 : 200 to 1 : 600 by weight.

18. The method according to claim 16, characterized in that the steps of treating medical instruments with the rust inhibiting lubricant are performed manually, wherein the rust inhibiting lubricant is diluted with water in a ratio of from 1 : 10 to 1 : 20 by weight.