JPS6035063A - Method of rust inhibition for automobile - Google Patents

Abstract

PURPOSE:To carry out a rust inhibiting treatment excellent in durability, etc., by coating the coated surface of an automobile with an emulsion type rust inhibitor contg. a mixed wax, an org. amine, a water-soluble resin, a polyalkylene wax and a metallic soap. CONSTITUTION:10-40wt% mixed wax having an acid value of 4-30mg.KOH/g obtd. by adding a waxy Rydrocarbon to an oxidized wax having an acid value of 10-60mg.KOH/g, an org. amine (e.g. trimethylamine) in a quantity of not more than 4 equivalents based on the acid value of the wax, 1-8wt% water-soluble resin, 1-20wt% polyethylene or polypropylene wax having a m.p. of 80 deg.C or above, 0.1-2wt% metallic soap and the balance of water are mixed together. The resulting emulsion type rust inhibitor is applied to the coated surface of an automobile body, engine room, etc. after assembling an automobile, to carry out a rust inhibiting treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rust prevention method for automobiles, and more particularly to rust prevention of areas that are particularly susceptible to rust on the painted outer surface of a car body, such as hinges or flanges of car body parts. , relates to a method for preventing rust in vehicle bodies such as the inside of the engine room and the outer surface of the aluminum die-cast engine.

Conventional technology In recent years, there has been a strong demand for improved quality for automobiles, such as the Canadian government's sub-regulations regarding rust (5 years warranty for external rust, 5 years for holey rust, 6 years warranty for structural rust), or as seen in Northern Europe. It is now mandatory to extend the lifespan of car bodies, such as by ensuring that exterior steel remains free of rust for eight years, and that rust and pitted rust do not occur in the car's structural parts for six years. Therefore, rust prevention measures are being implemented.

This rust prevention measure extends vehicle life, improves appearance quality,
This has the great advantage of extending the warranty period for parts, but
On the other hand, this leads to an increase in the cost of automobiles, especially for parts whose surfaces do not have anti-corrosion treatment, such as aluminum castings used in the engine body, or for the interior of the engine room where there are many assembled parts. If such countermeasures are taken, the cost will increase significantly, so there has been a demand to reduce the cost of anti-corrosion measures.One way to solve this demand is to spray anti-corrosion paint all over the engine room after the car is assembled, thereby reducing costs. A method has been proposed to minimize the increase and still provide the necessary rust prevention performance.

In this method, paints using organic solvents that form a coating film at room temperature, such as Evannitrocellulose-based lacquer clears and oil-based phthalate resin-based clears, are currently used as metal rust-preventing clears.

By the way, the usual steps before and after the assembly of an automobile are explained with reference to the drawings as follows. Assembly of the vehicle is completed in engine room assembly work step 1.

Next, the adjustment check process 2 begins, and alignment adjustment,
Adjustment checks such as headlamp adjustment, brake check and adjustment are carried out, a rain leak test is carried out in a shower test step 8, a final inspection is carried out in a completion inspection step 4, and the product is not shipped in the next step 5. Of these, processes 1-4 are performed within the process building 6. In such a process, if a paint using the above-mentioned organic solvent is applied after assembly is completed, the following problems will occur.

(]) Since the paint contains a large amount of organic solvent, if a large amount of the solvent is absorbed, it will have negative effects on the human body. There is also the danger of pollution and fire caused by organic solvents. In addition, it is necessary to install a booth to take fire prevention measures and environmental measures to prevent this, and there is a problem in that the equipment to be introduced becomes expensive. In addition, when the number of vehicles to be coated increases, processing on a conveyor or installation of stationary coating equipment becomes necessary.

However, because the coating is applied after vehicle assembly is completed or before a shower test, it is often applied within the assembly factory, and it requires a large investment in equipment to ensure complete prevention of fires. It was a difficult barking behavior.

(2) In order to ensure safety in the event of a fire, equipment is installed outside the assembly plant, and if completed vehicles are introduced there and coated with metal anti-corrosion clear, the vehicles must be exposed to rain using a shower tester. The product is led to the coating process after a leak test, and because the distance between the shower tester and the coating process is not that far, there is not enough time for water droplets adhering to the car body to dry naturally. For this reason, when the engine compartment is opened, water droplets flow into the engine compartment and adhere to the anti-rust clear coated surface, and if the anti-rust clear is applied without removing these water droplets, problems such as roughness and cratering may occur in the appearance of the paint film. This also causes a decrease in rust prevention ability, so it is necessary to completely remove water droplets, which requires a lot of man-hours.

(8) Since the anti-corrosion clear is applied by spray, there is a possibility of overspray to areas other than the engine room.
In particular, if oversprayed onto the exterior painted surface, the appearance of the paint film will be damaged. Since repair after drying and curing is extremely difficult, masking of the outer panel surface is required.

Furthermore, when performing automatic spraying, it is difficult to carry out automatic masking because only cars with the same shape are flowing along one line, which is also a cause of delays in automation.

On the other hand, the present applicant has developed a method using water-based resin as the main component, and added an aqueous silicone resin additive, an anionic surfactant, and a high-boiling alcohol as a coating surface conditioner. We proposed a rust prevention method in which a water-based water-based anti-corrosion paint with added water dispersion is applied inside the engine compartment of an automobile after the assembly is completed (Japanese Patent Publication No. 56-23665).

However, the above-mentioned water-dispersed water-based anti-rust paints have solved the problems of being a clear anti-rust paint, and of course have anti-rust properties, but if a strong stream of water, such as water from a hose, hits the paint film, it will become water resistant. There are problems with corrosion resistance, which in turn causes defects in the coating film, making it impossible to obtain stable rust prevention performance over a long period of time.

DISCLOSURE OF THE INVENTION In view of the above-mentioned current situation, the present inventors have solved the problems of rust-preventing clear paints, and have developed an anti-rust clear coating that uses water as a solvent and has excellent rust-preventing performance and water resistance, which are the weaknesses of water-dispersed water-based anti-rust paints. As a result of various research to develop a rust agent, acid value 10 ~ aomg・K
10 to 40% by weight of a mixed wax prepared by mixing a waxy hydrocarbon with a wax oxide having an OV9 so that the acid value of the wax is in the range of 4 to aomg KOH/liter;
An organic amine of not more than 4 equivalents based on the acid value of this mixed wax, ~8 parts by weight of a water-soluble resin, 1 to 20 parts by weight of polyethylene or polypropylene wax with a melting point of 80°C or higher, and 0.0 parts by weight of gold and soap. An emulsion-type rust preventive agent containing 1 to 2 parts by weight as a main component and the remainder being water is applied to the painted outer surface of the automobile body, the inside of the engine compartment, and the outer surface of the die-cast engine during construction of the automobile. The inventors have discovered that the problems associated with metal rust-preventing clears and water-based water-based rust-preventing paints can be solved by a rust-preventing method for automobiles, and have achieved the present invention.

' As mentioned above, the mixed wax which is the first component of the emulsion-type rust preventive agent used in the rust prevention method of the present invention is a wax-like carbonized wax oxide having an acid value of 10 to 60 KOH/g. Hydrogen, when the acid value of the mixed wax is 4~
The wax oxide is a mixture of aliphatic hydrocarbons such as polyethylene wax, polypropylene wax, paraffin wax, microcrystan wax, and α-olefin wax. 3 is a wax oxide with an acid value of 10 to 60 m9·KOH/9 obtained by reacting with an oxygen-containing gas in a conventional manner, where the acid value is 10·KOH/
If it is less than ';', the G emulsion becomes unstable, and if the acid value is greater than 60m9·KOH/g, its rust-preventing ability will decrease. Further, specific examples of waxy hydrocarbons that can be used include microcrystalline wax, paraffin wax, polyethylene wax, and α-olefin wax. In the present invention, the use of the wax oxide and waxy hydrocarbon in combination is essential, and has a synergistic effect of rust prevention.

The mixing ratio of the above-mentioned wax oxide and waxy hydrocarbon is such that the mixed wax acid value is in the range of 4 to 30 KOH/liter, and if the acid value is less than 4, the average particle size will be 20 μm or more, and the emulsion stability will be poor. Moreover, if the acid value is higher than 80, the emulsion tends to gel. Further, if the amount of mixed wax added is less than 10 parts by weight, the antirust ability will be insufficient, and if it exceeds 40 parts by weight, it will become gelled, which is not preferable.

As the organic amine of the second component, an alkylamine having 3 to 18 carbon atoms, an alcohol amine, morpholine, etc. can be used, and specific examples thereof include hexylamine, trimethylamine, laurylamine, and stearylamine.

Monoethanolamine, jetanolamine, triethanolamine, N,N-dimethylethanolamine,
N,N-diethylethanolamine, N,N-diisopropylethanolamine, N,N-dibutylethanolamine, N-(β-minoethyl)ethanolamine, N-methylethanolamine.

Examples include N-methyljetanolamine and morpholine. The amount added is 4 equivalents or less relative to the mixed wax, and if it exceeds 4 equivalents, water resistance will decrease.

Examples of the water-soluble resin as the eighth component include acrylic resin emulsions, polyacrylic acid having a content of % ii 1' 0.0 +10 or less, alkali salts of polyacrylic acid, and e.

Polyacrylic acid oxyester, polymethacrylate oxyester, molecular weight 20. (Polyethylene glycol with a molecular weight of less than 100, polyvinyl alcohol with a molecular weight of less than 100,000,
Examples include polyethyleneimine with a published number of 100,000 or less, carboxymethyl cellulose and its alkali salts with a molecular weight of 250,000 or less, alkali salts of isobutylene-maleic anhydride copolymer with a molecular weight of 100,000 or less, and polyethylene oxide with a molecular weight of 5,000,000 or less. The amount added is ~8 parts by weight,
Preferably, the emulsion viscosity is increased in the 1st to 5th part, and the sagging property (hereinafter referred to as sagging property) during application is improved.

If the melting point of the fourth component is polyethylene wax or polypropylene wax that is 80°C or higher, the interior of the engine room or the engine aluminum die-cast will reach a high temperature of about 120°C, so the rust preventive agent of the present invention This is not preferable because the formed coating film melts and sag (hereinafter referred to as secondary sag). The amount added is 1 to 20 parts by weight, and 1 to 20 parts by weight.
If it is less than 20 parts by weight, there will be a problem with secondary sagging, and if it is more than 20 parts by weight, there is a risk of cracking in the formed coating film, which is not preferable.

The sixth component, metal soap, is the alkali metal of normal fatty acids,
Alkaline earth metal, lead, zinc soap with 0 added amounts.
．． By adding in an amount of 1 to 2 parts by weight within this range, the adhesion of the coating film can be improved.

The emulsion type rust preventive used in the present invention is the first to
Although ba is an essential component, a small amount, preferably up to 5% by weight, of a solubilizing agent may be added as required. Mineral oil, liquid polybutene, and polyacrylic acid can be used as the solubilizing agent, and the solenoid action has the effect of making polyethylene wax or polypyrene wax having a melting point of 80° C. or higher compatible with other waxes. In particular, this melting aid is used when the melting point of the mixed wax is 100°C or higher,
It is also preferably added when an emulsion is prepared at normal pressure.

In the method of the present invention, an emulsion-type rust preventive agent having the composition as described above is applied to the interior of the engine room of the automobile after the assembly of the automobile, the outer surface of the engine aluminum die-cast F, and the painted outer surface of the vehicle body, particularly in areas where rust is likely to occur, e.g. Fuel filler lid hinge mounting area and entire flange circumference, cowl grille slide flange, hood hinge, hood inner relief hole, drill terminal, vertical flange terminal, air box flange terminal, upper flange terminal on front fender and hood ledge, Apply around door hinges, packed hinges, housing holes in slot towers, truck tailgate hinges, and plastic nuts in engine compartments. Since the rust preventive agent used in this case is water-based, problems associated with conventional air-drying organic solvent paints, such as flammability, toxicity, and pollution (]]), are solved, and conventional water-based dispersion paints The weak points of water resistance and rust preventive ability of the mold anti-corrosion paint have been solved, and the anti-corrosion ability is as good as the above-mentioned organic solvent paint, and the paint film remains stable in high-temperature environments, which is the weak point of wax compositions. The problem of so-called secondary sag, which is caused by melting, could be overcome.

EXAMPLES OF THE INVENTION Example Emulsion-type rust preventives of 8 diameters with dimensions 1 to 8 were prepared using the ingredients shown in Table 1 in various amounts according to the following method.

A wax oxide having an acid value shown in Table 1, a waxy hydrocarbon, and a metal soap were heated and melted at 180°C, and then an organic amine was added, and the mixture was stirred and mixed. On the other hand 9
The molten wax mixture is gradually dropped into hot water heated to 0°C or higher to form an emulsion, which is allowed to cool to 80 to 50°C. A water-soluble resin is added thereto and mixed uniformly to form an emulsion-type rust preventive agent A1. ~8. Here are the results obtained by testing according to the following test method on Comparative Example 4 metal rust preventive clear and A5 water-based dispersion resin paint consisting of 8 types of rust preventive agents and the compounding ingredients shown in Table 1 for comparison. Also listed in Table 2.

(a) Rust prevention test salt water spray! ! : Conforms to JISK2246. However, the film thickness is 15
The degree of rust occurrence after 600 hours of coating was 0±20 μm. The film thickness when measured was 50 μm. Average rust occurrence degree from 0.1 to 10.11 to 25.26 to 60 and 5l
-100C and indicated as A class, B class, 0 class, D class and E class, respectively.

(b) Lower part 20 of sagging test piece + 5poa species 210 x 800 ms +)
Mask 0Iu11 and spray rust preventive at pressure lc9
/C-, a film thickness of 50 μm was applied, the masking was removed, and the film was allowed to stand vertically in a thermostatic chamber at 60° C. for 80 minutes, after which the length of j was measured.

(c) Two permeability test pieces (SPOO type 70X150 Dragon) with a gap of 100
A laminated plate of μm is bent outward at about 60 degrees at the center of the plate (at the 175th point), and dripped with each rust preventive agent into the gap. After standing vertically for 24 hours, the bent plate is removed and the infiltration penetrates. The length was measured.

2) Drying test plate (SPOO type 1110 x 800 ms)
G, - Spray the rust preventive agent at a pressure of 5 to 9/C-1 film thickness] 50±
After applying 20 pm and allowing it to stand at room temperature for 80 minutes, those with no stickiness to the touch were judged to be acceptable, and those with stickiness were judged to be unacceptable.

(e) Apply each rust preventive agent to a water resistance test plate (SPOO type 210X800sII) at a pressure of 5 kg/cj11" and a film thickness of 150±.
2 (apply 1 μm, leave for 24 hours after application, then apply 20
It was immersed in tap water at °C for 72 hours, and changes in the state of the film were visually observed.

(f) Paint film removability Examine the ease of removing oversprayed paint.

(g) Secondary sagging property Coat a film thickness of 150±20 μm on a horizontal test plate.

After drying for 24 hours, it was heated to 180℃ for 1 hour,
Its vertical length was measured.

(a) Spray each thermochromic rust preventive agent onto a test plate coated with white enamel at a pressure of 5
kg/cm”, film thickness]50±2074m applied,
After drying for 24 hours after coating, yellowing was investigated when heated at 180°C for 1 hour.

From the results shown in Table 1 and Table 2, the emulsion type rust preventive agent used in the present invention solves all the problems of conventional metal rust preventive clears and water-based dispersion resin paints, and is an excellent automotive rust preventive agent. I understand.

As described in detail, the method of the present invention uses an organic solvent such as mineral spirits, uses water as a solvent,
After the car is assembled, we use a wax emulsion rust inhibitor that cures at room temperature and has excellent rust prevention performance, drying properties, water resistance, stain resistance, and high temperature coating stability, and is easy to repair after application.
Because it is applied to the painted exterior of automobile bodies, the inside of the engine room, and the exterior of engine aluminum die-casting, there is no risk of pollution or fire that occurs with conventional metal rust prevention clears that use organic solvents. Not only does it not require any equipment, but it also eliminates the defects that occur when using conventional water-dispersed water-based anti-caking paints, and the formed paint film lasts for a long time. It maintains excellent rust prevention performance for a long period of time and has excellent water resistance, especially for use in engine rooms or brackets in engine rooms under high temperature environments.
The effect of this method is that it is suitable for preventing rust on the outer surface of die-cast engine aluminum.

[Brief explanation of the drawing]

FIG. 1 is a process diagram from assembly to shipment of a private LLT vehicle. 1... Assembly work process 2... Adjustment check process 8.
...Shower test process 4...Complete inspection process b...Shipping process 6...Process building. Patent applicant Nissan Motor Co., Ltd. No. 1-9

Claims (1)

[Claims] 1 Mixed wax hydrocarbon with wax oxide having an acid value of 10 to 60119-KOH/g. 10 to 40 mixed waxes are mixed so that the acid value of the wax is in the range of 4 to 80 KOH/g. Curse, an organic amine of 4 equivalents or less based on the acid value of this mixed wax, and a water-soluble resin of 1
~8 parts by weight, 20 parts by weight of polyethylene polypropylene wax having a melting point of 80°C or higher, and 0 parts by weight of metal soap.
．． 1~2ffiii ¥! An emulsion-type rust preventive agent containing M as a main component and the remainder being water is applied to the painted exterior surface of the vehicle body, the interior of the engine compartment, and the exterior die-cast surface of the vehicle after the vehicle is assembled. Rust prevention method.