JPH0335350B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a rust preventive agent for car bodies, and more specifically, a rust preventive agent that can be applied to car body bag structures, plate joints, hinges, etc., and has excellent steam kerosene resistance, durability, etc. Regarding. Conventional Technology In recent years, automobiles have been used in a variety of conditions and environments, and the bodies of automobiles used in particularly cold regions are affected by rock salt and other antifreeze agents that are sprayed on the road surface in winter. It has become essential to apply rust inhibitors. Conventionally, as rust preventive agents for car body bag structures, plate joints, and hinges, so-called wax-type preventive agents have been used, which are compositions in which wax and various anti-rust additives are dissolved or dispersed in mineral spirits or other organic solvents. Rust agents have been used. Wax-type rust inhibitors are widely used due to their excellent rust prevention, permeability, and anti-sagging properties. (hereinafter referred to as "steam kerosene"), etc., has the disadvantage that the film may come off. The paint surface protectant is usually removed just before a new car is delivered to the user, but the treatment liquid used at that time, such as steam kerosene, may scatter on the wax-type rust preventive coating. This causes the film to come off, and the rust prevention properties are greatly reduced. Problems to be Solved by the Invention In view of the above-mentioned current situation, we provide a rust preventive agent for car bodies that has excellent rust preventive properties and whose film does not easily fall off when treated with steam kerosene or the like used when removing a painted surface protective agent. It is an object of the present invention to do so. Therefore, as a result of intensive research to solve the above problems, the present inventors found that by adding acrylic resins and alkyd resins to wax-type rust preventive agents, they improved rust prevention, water resistance, and moisture resistance. The present inventors have discovered that these properties are highly retained and exhibit excellent solvent resistance, particularly steam kerosene resistance, and have completed the present invention based on these findings. Means for Solving the Problems That is, the gist of the present invention is that: (a) an acrylic resin and/or an alkyd resin, (b) a microcrystalline wax, and (c) an anticorrosive additive are contained as essential components; The weight ratio based on nonvolatile content is 10 to 100 parts of component (b) to 100 parts of component (a).
1000 parts There is a rust preventive agent for car bodies, characterized in that component (c) is 10 to 800 parts. Hereinafter, the constituent elements of the present invention will be explained in detail. (Acrylic Resin and Alkyd Resin) As the acrylic resin, various acrylic resins such as polymethacrylic ester such as polymethyl methacrylate resin or polyacrylic ester can be used. Examples of alkyd resins include alkyd resins whose main components are phthalic acid and glycerin, oil-modified alkyd resins modified with fatty acids that are components of oils and fats, such as linseed oil-modified alkyd resins, soybean oil-modified alkyd resins, and other resin acids. Modified alkyd resins include various alkyd resins such as rosin-modified alkyd resins, phenol-modified alkyd resins, vinyl-modified alkyd resins, urethane-modified alkyd resins, and oil-modified alkyd resins are particularly preferred. Commercially available acrylic resins and alkyd resins can be used, and these can be used alone or in combination. (Microcrystalline wax) Microcrystalline wax is not particularly limited as long as it is normal, but it has a melting point of 60°C to 100°C.
℃ is preferred. (Rust preventive additive) Any rust preventive additive used in the present invention can be suitably used as long as it is used together with wax in a so-called wax type rust preventive agent. Such anti-rust additives include, for example, sulfonic acid salts such as barium or calcium salts of alkyl sulfonic acids or alkylaryl sulfonic acids, alkaline earth metal salts of petroleum sulfonic acids; petrolatum oxide; oxidized microcrystalline waxes; ; oxidized paraffin; metal soaps such as barium salts or calcium salts of carboxylic acids such as lanolin fatty acids; and the like. It is appropriate for oxidized petrolatum, oxidized microcrystalline wax, and oxidized paraffin to all have an acid value of 20 to 100. These antirust additives may be used alone or in combination of two or more. (Blend of each component) The rust preventive agent for car bodies of the present invention is used by dissolving or dispersing each of the above components in an organic solvent such as mineral spirits. The blending ratio of each component (a), (b), and (c) is such that the weight ratio based on nonvolatile content is 10 to 1000 parts of component (b) to 100 parts of component (a), preferably 50 to 1000 parts. 150 parts, and component (c) is 10 to 800 parts, preferably 100 to 200 parts. If the content of component (b) is less than 10 parts, the thixotropy will be low, so when a rust preventive is applied, the anti-sagging properties will be poor and it will not be possible to obtain a uniform film thickness.
If it exceeds 1,000 parts, the permeability into gaps such as plate joints will be extremely reduced, and solvent resistance such as steam kerosene resistance will also be inferior. If the amount of component (c) is less than 10 parts, long-term rust prevention cannot be obtained, and if it exceeds 800 parts, the coating will come off due to treatment with steam kerosene, etc., and it cannot be put to practical use. Volatile components include organic solvents such as mineral spirits, other solvents contained in resin raw materials, and mineral oil contained in mineral oil diluted sulfonates. The rust preventive agent for car bodies of the present invention is used by dissolving or dispersing it in an organic solvent such as mineral spirits, as described above. The proportion of the total non-volatile content contained therein can be arbitrarily determined as desired, but in view of the application workability, permeability, anti-sagging properties, etc. of the rust preventive agent, the proportion of non-volatile content is usually set at 10%. ~
It is used at 80% by weight, preferably from 30 to 60%. (Other optional components) In addition to the above-mentioned essential components, the rust preventive agent for car bodies of the present invention contains minerals for the purpose of adjusting the hardness of the film, adjusting the viscosity during application, improving drying properties, or preventing deterioration of the film over time. Oil plasticizers, waxes such as paraffin,
Organic solvents, antioxidants, ultraviolet absorbers, anti-sagging agents, and dryers (manganese salt, cobalt salt)
etc. can be included as appropriate. (How to use) The method of applying the rust preventive agent for car bodies of the present invention to the car body is to heat the rust preventive agent to room temperature or a range from room temperature to about 90°C, and apply it by spraying or brushing. There is a method of applying it. If the desired anti-sagging properties cannot be obtained by applying at room temperature, the anti-sagging properties can be improved by applying at a heated temperature. EXAMPLES Next, the present invention will be specifically explained using examples and comparative examples. However, the present invention is not limited in any way by these Examples and Comparative Examples. Table 1 shows the car body rust preventive agent of the present invention (Examples 1 to 6)
and compositions of comparative examples (comparative examples 1 to 4) are shown. Note that the numerical values regarding the composition of the components represent parts by weight. (Performance Test) In order to clarify the performance of the rust preventive agent for car bodies of the present invention, a performance test was conducted on the rust preventive agents for car bodies shown in Table 1. The items and test methods are listed below, and the results are shown in Table 2. (1) Penetration The jig (test instrument) shown in Figure 1 is left suspended (temperature 20℃), and 1 ml of the sample heated to the temperature shown in Table 2 is dropped into the jig clearance from above. Then, measure the penetration length after standing at 20℃ for 24 hours. Although the jig in Fig. 1 is not shown,
Aluminum strips 0.1 mm thick and 10 mm wide are placed on both left and right ends as spacers to create clearance. (2) Primary anti-sag property The jig (testing device) shown in Figure 2 made by bending a steel plate was left standing (temperature 20℃), and 1ml of the sample heated to the temperature shown in Table 2 was placed 20mm from the top. Drop it at the center point and measure the length of sagging after leaving it at 20℃ for 1 hour. (3) Secondary sag prevention property A sample at 20°C was applied to a dull steel plate (dimensions 70 x 150 x 0.8 mm) whose lower half was masked with cloth adhesive tape to a dry film thickness of 100 μm, and immediately masked (adhesive). Remove the tape) and dry at 20℃ for 24 hours. After drying, the dull steel plate is placed vertically in a thermostat at 80°C for 1 hour, and the presence or absence of sagging of the film is observed. (4) Cracks test Spot 20ml of the sample at 20°C on the jig (testing equipment) shown in Figure 3, dry at 20°C for 7 days, and check for cracks. The sample is shown in Figure 3b.
If it accumulates and is not flexible when it dries and shrinks, it will cause cracks on the surface. (5) Salt spray test: JISK2246 (hereinafter referred to as "SST") Edge-sealed degreased dull steel plate (70 x 150 x 0.8
Apply the sample to a dry film thickness of 50 μm. Next, after drying at 20°C for 72 hours, SST is performed for 500 hours. (SST salt solution has a NaCl concentration of 5% and a test temperature of 35℃) (6) Water resistance A test piece (hereinafter referred to as "TP") prepared in the same manner as the SST method in (5) was immersed in water at 20℃ for 72 hours. death,
Check the condition of the film. (7) Moisture resistance: JISK2246 (5) TP prepared in the same manner as the SST method was placed in a wet box (50
℃, 98%RH) and examine the condition after 120 hours. (8) Steam kerosene resistance test A sample was applied to an electrodeposited steel plate (100 x 200 x 0.8 mm) to a dry film thickness of 100 μm, and after being left at room temperature for 20 days,
Steam kerosene is sprayed under the conditions shown below, and after drying, the remaining rate of the film is determined by the method of equation (1), and the steam kerosene resistance is examined. In addition, a painted surface protective agent (Yushiron Coat C-77 manufactured by Yushiro Chemical Industry Co., Ltd.) was tested under the above conditions to examine its removability with steam kerosene. (Steam kerosene spray conditions) ・Test machine Kobe Kosakusho HW-850NC ・Kerosine content 2% ・Outlet water temperature 50℃ ・Water pressure 0.98MPa (10Kg/cm ² ) ・Water volume 650/hour ・Spray time 2 minutes・Spray method Method A shown in Figure 4 and Method B shown in Figure 5 Film residual rate (weight %) = b/a x 100 (1) Formula a: Film weight (g) 20 days after application b: Film weight (g) after steam kerosene spray and air drying at room temperature for 24 hours

【table】

【table】

[Table] Effects of the Invention The car body rust preventive agent of the present invention retains the excellent rust preventive performance, water resistance, and moisture resistance of conventional wax-type rust preventive agents, and also maintains the excellent rust prevention properties, water resistance, and moisture resistance of conventional wax-type rust preventive agents. When cleaning and removing the paint film protectant using a treatment such as steam kerosene, the film does not fall off even if the treatment liquid is splashed onto the rust preventive film, providing excellent rust prevention effects over a long period of time. do.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the jig used for the permeability test, FIG. 2 is a schematic diagram of the jig used for the temporary sag prevention test, and FIG. 3 is a schematic diagram of the jig used for the crack test. Figure 4 is a schematic diagram of the steam spray method (method A) when steam kerosene resistance was evaluated, and Figure 5 is a schematic diagram of the steam kerosene spray method (method B).
This is a schematic diagram of the method.

Claims (1)

[Scope of Claims] 1. Contains (a) an acrylic resin and/or an alkyd resin, (b) a microcrystalline wax, and (c) an antirust additive as essential components, and has a weight ratio based on nonvolatile content as described above. 10 to 100 parts of (b) component per 100 parts of (a) component
1000 parts A rust preventive agent for car bodies, characterized in that component (c) is 10 to 800 parts. 2. The rust preventive agent for a vehicle body according to claim 1, wherein the rust preventive additive is at least one selected from sulfonic acid salts, petrolatum oxide, microcrystalline oxide wax, paraffin oxide, and metal soap.