A cleaning and rust-preventing agent suitable for multi-material automobile parts and its preparation method

Abstract

The present invention discloses a cleaning and rust-preventive agent suitable for multi-material automotive parts. The agent comprises the following components by weight: 7% to 8.5% alkali salt, 2.5% to 3% chelating agent, 8% to 12% nonionic surfactant, 0.2% to 0.5% cationic surfactant, 2% to 2.5% rust inhibitor, 0.5% to 1% corrosion inhibitor, and the balance water. The cleaning and rust-preventive agent effectively solves the problem of simultaneous cleaning of ferrous metals, die-cast aluminum alloys, and magnesium alloys, which cannot simultaneously achieve cleaning, rust prevention, and corrosion inhibition for non-ferrous metals. The cleaning and rust-preventive agent can simultaneously ensure cleanliness and corrosion inhibition when cleaning multiple materials while maintaining a stable stock solution.

Description

Technical Field

[0001] The present invention relates to a cleaning and rust-preventing agent suitable for automobile parts made of multiple materials, and also relates to a preparation method of the cleaning and rust-preventing agent. Background Art

[0002] The primary challenge facing new energy vehicles is range. In addition to battery performance, vehicle weight also significantly impacts range. Compared to traditional fuel vehicles, new energy vehicles require even greater lightweighting to address the increased weight associated with electrification, thereby improving range and power. Research shows that for every 10kg reduction in vehicle weight, pure electric vehicles can increase their range by 2.5km.

[0003] Currently, die-cast aluminum and magnesium alloys are widely used in lightweight automotive applications due to their excellent mechanical properties. However, since aluminum and magnesium are both very flexible metals, their processing is also relatively difficult. This is especially true when processing multiple materials on the same line, and the versatility of the metalworking media, especially cleaning and rust inhibitors, needs to be considered. Most automotive parts companies process parts made of multiple materials, including ferrous metals, die-cast aluminum alloys, and die-cast magnesium alloys. After machining, these parts often require cleaning using specialized cleaning agents on separate cleaning lines to avoid issues with cleanliness, corrosion, and product stability. This not only increases the company's equipment and manpower investment, increases management complexity, but also reduces cleaning efficiency. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a cleaning and rust-inhibiting agent suitable for multi-material automotive parts. The cleaning and rust-inhibiting agent can simultaneously ensure the cleanliness and corrosion inhibition effect when cleaning multiple materials on the basis of ensuring the stability of the original liquid; another purpose of the present invention is to provide a preparation method of the above-mentioned cleaning and rust-inhibiting agent.

[0005] Technical solution: The cleaning and rust-preventive agent suitable for multi-material automobile parts of the present invention is composed of the following components in weight percentage: 7% to 8.5% of alkali salt, 2.5% to 3% of chelating agent, 8% to 12% of non-ionic surfactant, 0.2% to 0.5% of cationic surfactant, 2% to 2.5% of rust inhibitor, 0.5% to 1% of corrosion inhibitor and the balance of water.

[0006] Among them, the alkali salt is a composition of potassium hydroxide and sodium metasilicate pentahydrate mixed in a mass ratio of 5:3.5 to 5:2; potassium hydroxide is used to remove metal powder on the surface of the cleaned parts, and potassium hydroxide and sodium metasilicate pentahydrate can only be synergistically resisted from the corrosion and discoloration of the die-cast aluminum alloy by potassium hydroxide through sodium metasilicate pentahydrate and corrosion inhibitor in the above ratio; if sodium metasilicate pentahydrate is replaced with potassium pyrophosphate or sodium tripolyphosphate that has a corrosion inhibition effect on aluminum alloy, the processed surface will turn yellow and dark after cleaning the die-cast magnesium alloy.

[0007] The corrosion inhibitor is prepared by the following method: a 65% aqueous solution of sodium N-methyltaurate and methanol in a mass ratio of 1:1 are placed in a four-necked flask equipped with a stirring device, a thermometer, and a dropping funnel. An epoxysilane of equal mass to the sodium N-methyltaurate is added to the dropping funnel. The dripping rate is controlled at 5 g / min and the reaction temperature is 25-50°C. After the dropwise addition is completed, pure water equivalent to twice the mass of the sodium N-methyltaurate is added to the mixture. The methanol and water are distilled off by heating to obtain the corrosion inhibitor. The main component of the corrosion inhibitor is the ring-opening reaction product of sodium N-methyltaurate on epoxysilane. The nitrogen atom in the sodium N-methyltaurate is connected to the CH2 group after the epoxy ring opening.

[0008] The corrosion inhibitor is a modified siloxane. It not only produces a synergistic corrosion inhibition effect with sodium metasilicate pentahydrate, combating corrosion and discoloration of die-cast aluminum alloys, but also increases the stability of the stock solution, overcoming the turbidity and flocculent precipitation that occurs when sodium metasilicate pentahydrate is stored at room temperature to 50°C. The biggest challenge with sodium metasilicate pentahydrate in aqueous solution is its stability, which easily leads to the precipitation of a white precipitate. Modifying epoxysiloxane with hydrophilic groups increases the solubility of sodium metasilicate pentahydrate after hydrolysis in water. Furthermore, the presence of a high Si-OH group in the aqueous solution can inhibit the hydrolysis of sodium metasilicate pentahydrate.

[0009] Wherein, the epoxysilane is γ-glycidyloxypropyltrimethoxysilane or γ-glycidyloxypropyltriethoxysilane.

[0010] The chelating agent is citric acid or EDTA; the selected chelating agent can effectively disperse metal ions in the cleaning bath (these metal ions are generated by metal powder on the surface of the part to be cleaned), preventing secondary deposition of metal ions on the cleaned surface, thereby achieving a brightening effect on the metal surface after cleaning. If salts of citric acid and EDTA, such as sodium citrate and EDTA-4Na salt, are used, the brightening effect will not be achieved. If the amount of citric acid and EDTA exceeds 3%, hydrogen gas will be generated when cleaning magnesium alloys, and the processed surface will become dark and lose its luster. If the amount is less than 2.5%, the metal ions cannot be effectively dispersed, and the brightening effect after cleaning cannot be achieved.

[0011] Among them, the non-ionic surfactant is a composition of carbonyl alcohol EO-PO block polyether and branched secondary alcohol polyoxyethylene ether mixed in a mass ratio of 5:3. Only in the above ratio can the carbonyl alcohol EO-PO block polyether and the branched secondary alcohol polyoxyethylene ether ensure both foam suppression ability and oil emulsification ability. When the ratio of the former is lower than 5 or the ratio of the latter is higher than 3, the foam suppression ability is insufficient. When the ratio of the former is higher than 5 and the ratio of the latter is lower than 3, the oil emulsification ability is insufficient.

[0012] Among them, the carbon chain of carbonyl alcohol EO-PO block polyether is isomeric C8~C10, and the composition ratio of EO to PO is 5:5; the carbon chain length of carbonyl alcohol EO-PO block polyether is selected to be C8~C10, taking into account wetting, rapid penetration and surface activity. When the carbon chain is less than 8, the activity is low, and when the carbon chain is higher than 10, the penetration ability is weakened; the composition ratio of EO to PO is 5:5, taking into account low foaming, foam suppression and cleaning ability. When the EO number is lower, the cleaning ability decreases, and when it is higher, the foam performance deteriorates. When the PO number is lower, the foam suppression ability deteriorates, and when it is higher, the water solubility deteriorates. When the ratio of the two is 5:5, it can not only maintain good cleaning ability and low foaming performance, but also can be used for other surfaces above 50°C. The foam of the surfactant has an inhibitory effect; the carbon chain of the branched secondary alcohol polyoxyethylene ether is C12, including three methyl substituents, and the EO number is 5-6; the use of the branched secondary alcohol polyoxyethylene ether is to utilize its super strong emulsification ability to form a synergistic effect with the permeability of the carbonyl alcohol EO-PO block polyether, so that the cleaning liquid can first quickly penetrate into the surface to be cleaned and remove the oil stains through emulsification. The EO number is 5-6, which can well coordinate the surface activity and foam performance. When the EO number is lower than 5, the surface activity is reduced and more solubilizers are required for solubilization. When the EO number is higher than 6, the foam is too rich and the carbonyl alcohol EO-PO block polyether cannot have an inhibitory effect on it at 50°C.

[0013] Among them, the cationic surfactant is di-C16~C18 alkyl dihydroxyethyl ammonium chloride, the main function of which is that the quaternary ammonium salt positive ions and hydroxyethyl groups are adsorbed on the cleaned metal surface, and the alkyl chains are facing outward to form a protective effect, thereby reducing the secondary contamination of impurities on the cleaned surface and water stains, and making the processed surface have a certain gloss after cleaning.

[0014] The rust inhibitor is a C21 dibasic acid synthesized from tall oil acid, ricinoleic acid or rapeseed oil acid and acrylic acid through the Diels-Alder reaction. The rust inhibitor has good compatibility with sodium metasilicate pentahydrate and will not produce white flocs and precipitation.

[0015] The above-mentioned preparation method of the cleaning and rust preventive agent is specifically as follows: adding a formulated amount of pure water into a reactor, adding an alkali salt into the reactor at room temperature, stirring until uniform and transparent, adding a chelating agent and stirring until uniform and transparent, then adding a nonionic surfactant, a cationic surfactant and a rust preventive respectively, and stirring until uniform and transparent; finally, adding a corrosion inhibitor and stirring until uniform and transparent, and controlling the feeding speed within 5kg / min, otherwise agglomeration is likely to occur, thereby obtaining a stable stock solution of the cleaning and rust preventive agent.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The cleaning and rust-preventing agent of the present invention effectively solves the problem that the co-linear cleaning of ferrous metals, die-cast aluminum alloys and magnesium alloys cannot simultaneously take into account cleaning, rust prevention and corrosion inhibition of non-ferrous metals (including die-cast aluminum alloys and magnesium alloys). The cleaning and rust-preventing agent of the present invention can simultaneously ensure the cleanliness and corrosion inhibition effect of various materials when cleaning on the basis of stable stock solution; (2) The cleaning and rust-preventing agent of the present invention can achieve the effect of brightening the metal surface after cleaning die-cast aluminum alloys and magnesium alloys; (3) It solves the problem of sodium metasilicate and The problem of incompatibility of organic carboxylic acids is solved by combining with C21 long carbon chain dibasic acid, so that silicate will not react to produce white precipitate during the preparation of cleaning and rust inhibitor; (4) By combining with corrosion inhibitor, the problem of long-term storage stability of silicate itself in aqueous solution is solved. No white precipitate is produced whether it is placed at room temperature or 50℃; (5) By combining with surfactants of specific structure and mixing ratio, after cleaning parts, it can meet the requirements of 42mN / m dyne pen without shrinkage within 5 seconds, and at the same time meet the low foaming performance at 50℃, and can be used for spray cleaning. DETAILED DESCRIPTION

[0017] Example 1

[0018] The present invention is suitable for a cleaning and rust-preventing agent for automobile parts made of multiple materials. The cleaning and rust-preventing agent comprises the following components in percentage by weight: 5% of sodium metasilicate pentahydrate, 2.5% of potassium hydroxide, 3.0% of EDTA, 5% of carbonyl alcohol EO-PO block polyether, 3% of branched secondary alcohol polyoxyethylene ether, 0.2% of di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% of C21 dibasic acid, 0.5% of a siloxane modifier, and the balance being water.

[0019] Example 2

[0020] The present invention is suitable for a cleaning and rust-preventing agent for automobile parts made of multiple materials. The cleaning and rust-preventing agent comprises the following components in percentage by weight: 5% of sodium metasilicate pentahydrate, 3% of potassium hydroxide, 3% of citric acid, 5% of carbonyl alcohol EO-PO block polyether, 3% of branched secondary alcohol polyoxyethylene ether, 0.2% of di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% of C21 dibasic acid, 0.5% of a silicone modifier, and the balance being water.

[0021] Example 3

[0022] The present invention is suitable for a cleaning and rust-preventing agent for automobile parts made of multiple materials. The cleaning and rust-preventing agent comprises the following components in percentage by weight: 5% of sodium metasilicate pentahydrate, 2.5% of potassium hydroxide, 3% of EDTA, 5% of carbonyl alcohol EO-PO block polyether, 3% of branched secondary alcohol polyoxyethylene ether, 1% of di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% of C21 dibasic acid, 1% of a silicone modifier, and the balance being water.

[0023] Comparative Example 1

[0024] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 3% branched secondary alcohol polyoxyethylene ether, 0.2% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, and the balance water.

[0025] Comparative Example 2

[0026] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% potassium pyrophosphate, 3% potassium carbonate, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 3% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, 1% silicone modifier, and the balance water.

[0027] Comparative Example 3

[0028] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 3% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 1% silicone modifier, and the balance water.

[0029] Comparative Example 4

[0030] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA-4Na, 5% carbonyl alcohol EO-PO block polyether, 3% branched secondary alcohol polyoxyethylene ether, 2% C21 dibasic acid, 1% silicone modifier, and the balance water.

[0031] Comparative Example 5

[0032] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 3% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% sebacic acid, 1% silicone modifier, and the balance water.

[0033] Comparative Example 6

[0034] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 3% carbonyl alcohol EO-PO block polyether, 5% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, 1% silicone modifier, and the balance water.

[0035] Comparative Example 7

[0036] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether (the ratio of EO to PO is 10:4, such as Antarox BL-240), 3% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, 1% siloxane modifier, and the balance water.

[0037] Comparative Example 8

[0038] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 2% branched secondary alcohol polyoxyethylene ether, 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, 1% silicone modifier, and the balance water.

[0039] Comparative Example 9

[0040] A cleaning and rust preventive agent is composed of the following components in percentage by weight: 5% sodium metasilicate pentahydrate, 2.5% potassium hydroxide, 3% EDTA, 5% carbonyl alcohol EO-PO block polyether, 3% secondary alcohol polyoxyethylene ether (such as DOW15-S-7), 1% di-C16-C18 alkyl dihydroxyethyl ammonium chloride, 2% C21 dibasic acid, 1% siloxane modifier, and the balance water.

[0041] The performance indicators of the cleaning and rust preventive agents of Examples 1 to 3 and Comparative Examples 1 to 8 are shown in Table 1.

[0042] Table 1

[0043]

[0044]

[0045] Note: a represents the test method for the corrosion inhibition performance of die-cast aluminum alloys and magnesium alloys. Parts made of AlSi12Cu and AZ91D are washed in a 5% working solution at 50°C for 5 minutes. After rinsing with tap water, they are blown dry with hot air from a hair dryer. The surface of the parts is observed for corrosion and discoloration. A reduction in the brightness of the processed surface is also considered discoloration.

[0046] b represents the test method for the brightness of parts after cleaning. Parts made of AlSi12Cu and AZ91D are washed in 5% and 50℃ working fluid for 5 minutes, and then blown dry with hot air from a hair dryer. If there is no obvious change on the non-machined surface of the parts, it is recorded as the original color. If it is brighter than before cleaning, it is recorded as bright.

[0047] c represents the test method for the cleanliness of parts after cleaning. Parts made of 45# steel, AlSi12Cu and AZ91D are washed in a 5% and 50℃ working fluid for 5 minutes, then blown dry with hot air from a hair dryer. After the parts cool to room temperature, they are marked with a 42mN / m dyne pen. After 5 seconds, they are observed to see if they shrink. If they do not shrink, they are qualified, otherwise they are unqualified.

[0048] It can be seen from Table 1 that the cleaning and rust-preventive stock solutions prepared in Examples 1 to 3 are stable at room temperature and 50°C, and have an anti-rust effect on ferrous metals. After cleaning die-cast aluminum alloys and magnesium alloys at 50°C, non-ferrous metals do not show any corrosion or discoloration, and the appearance is brighter, with low foaming, and the cleanliness can pass the 42mN / m dyne pen test. In Comparative Example 1, no corrosion inhibitor was added, the stock solution was unstable, the aluminum alloy had insufficient corrosion inhibition, and the appearance was corroded and discolored; in Comparative Example 2, potassium pyrophosphate and potassium carbonate were used to replace the alkali salt of the present invention. After cleaning at 50°C, the magnesium alloy corroded and discolored, and bubbles were generated; in Comparative Example 3, no rust inhibitor was added, and the anti-rust effect was significantly reduced; in Comparative Example 4, EDTA-4Na was used to replace EDTA, and the cationic surfactant was removed. After cleaning at 50°C, the appearance of the aluminum alloy and magnesium alloy did not become bright; in Comparative Example 5, sebacic acid was used to replace the C21 dibasic acid rust inhibitor of the present invention, and the stock solution The stability is insufficient, and the corrosion inhibition performance of the aluminum alloy decreases and discolors after cleaning at 50°C; in Comparative Example 6, after changing the ratio of carbonyl alcohol EO-PO block polyether and branched secondary alcohol polyoxyethylene ether, the foam performance deteriorates significantly; in Comparative Example 7, after changing the addition ratio of EO and PO in the carbonyl alcohol EO-PO block polyether molecule, the foam performance deteriorates seriously; in Comparative Example 8, the amount of branched secondary alcohol polyoxyethylene ether is reduced, and the cleanliness does not meet the standard after cleaning at 50°C; in Comparative Example 9, secondary alcohol polyoxyethylene ether is used instead of branched secondary alcohol polyoxyethylene ether, and the cleanliness does not meet the standard after cleaning at 50°C.

Claims

1. A cleaning and rust-proofing agent suitable for multi-material automobile parts, characterized in that: The invention is composed of the following components in percentage by weight: 7% to 8.5% of an alkali salt, 2.5% to 3% of a chelating agent, 8% to 12% of a nonionic surfactant, 0.2% to 0.5% of a cationic surfactant, 2% to 2.5% of a rust inhibitor, 0.5% to 1% of a corrosion inhibitor, and the balance being water; the corrosion inhibitor is a modified siloxane; the alkali salt is a composition obtained by mixing sodium metasilicate pentahydrate and potassium hydroxide in a mass ratio of 5:3.5 to 5:2; the nonionic surfactant is a composition obtained by mixing carbonyl alcohol EO-PO block polyether and branched secondary alcohol polyoxyethylene ether in a mass ratio of 5:3; and the rust inhibitor is a C21 dibasic acid.

2. The cleaning and rust-preventing agent for multi-material automobile parts according to claim 1, characterized in that: The corrosion inhibitor is prepared by the following method: a 65% sodium N-methyltaurate aqueous solution and methanol are placed in a 1:1 mass ratio into a four-necked flask equipped with a stirring device, a thermometer, and a dropping funnel; epoxy silane of the same mass as the sodium N-methyltaurate is added to the dropping funnel; the dripping rate is controlled to be 5 g / min and the reaction temperature is controlled to be 25-50° C.; after the dropwise addition is completed, pure water equivalent to twice the mass of the sodium N-methyltaurate is added to the mixture; methanol and water are distilled off by heating to obtain the corrosion inhibitor.

3. The cleaning and rust-preventing agent for multi-material automobile parts according to claim 2, characterized in that: The epoxysilane is γ-glycidyloxypropyltrimethoxysilane or γ-glycidyloxypropyltriethoxysilane.

4. The cleaning and rust-preventing agent for multi-material automobile parts according to claim 1, characterized in that: The chelating agent is citric acid or EDTA.

5. The cleaning and rust-preventing agent for multi-material automobile parts according to claim 1, characterized in that: The carbon chain of the carbonyl alcohol EO-PO block polyether is isomeric C8~C10, and the composition ratio of EO to PO is 5:5; the carbon chain of the branched secondary alcohol polyoxyethylene ether is C12, including three methyl substituents, and the EO number is 5~6.

6. The cleaning and rust-preventing agent for multi-material automobile parts according to claim 1, characterized in that: The cationic surfactant is di-C16~C18 alkyl dihydroxyethyl ammonium chloride.

7. The method for preparing the cleaning and rust-preventing agent according to claim 1, characterized in that: Specifically, the method comprises the following steps: adding the formulated amount of pure water into the reactor, adding an alkali salt into the reactor at room temperature, stirring until uniform and transparent, adding a chelating agent and stirring until uniform and transparent, then adding a nonionic surfactant, a cationic surfactant and a rust inhibitor respectively, stirring until uniform and transparent; finally, adding a corrosion inhibitor and stirring until uniform and transparent, and controlling the feeding speed within 5kg / min, otherwise agglomeration is likely to occur, thereby obtaining a stable stock solution for cleaning the rust inhibitor.

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