Antirust composition and automobile component

Abstract

The present invention addresses the problem of providing an antirust composition having sufficient corrosion resistance, being excellent in viscosity reduction rate in response to temperature rise, and hardly causing sagging due to temperature rise when formed into a coating film.　The problem is solved by an antirust composition comprising an antirust additive, bentonite, a filler, a hardened oil, and a diluent, wherein the content of wax is in the range of 0%-1% by mass, the content of the antirust additive is in the range of 16%-35% by mass, the content of bentonite is in the range of 2%-6% by mass, and the viscosity reduction rate in the temperature range of 20°C-80°C is 25% or less.

Description

Rust prevention composition and automobile parts

[0001] The present invention relates to a rust-preventive composition and to an automobile part having a rust-preventive coating film made of the rust-preventive composition. Technology background

[0002] Wax-type rust inhibitors, which are rust-preventive compositions in which wax and various additives are dissolved or dispersed in a diluent such as an organic solvent, have been used as rust inhibitors used to improve the rust-preventive performance of bag structures such as the underside of the floor, doors, and hood of an automobile body.

[0003] For example, Patent Document 1 discloses a rust-preventive composition containing a rust-preventive additive, a wax, a hardened oil, and a diluent, and further containing 2 to 6 mass % of bentonite based on the total mass of the composition.

[0004] Patent No. 6133660

[0005] The paint films containing anti-rust agents used on automobile bodies are exposed to heat from the exhaust heat while the car is running and from the glare of the sun in summer. Therefore, the paint film must be able to maintain its shape without sagging even under heat.

[0006] The rust-preventive composition disclosed in Patent Document 1 can maintain a constant film thickness even when heated after application, but has the property that the film thickness at the time of application also becomes thicker accordingly, and sagging occurs in proportion to the difference in film thickness retention between when applied and when heated, so there is room for improvement.

[0007] An object of the present invention is to provide a rust-preventive composition that has sufficient corrosion resistance, an excellent rate of viscosity reduction with temperature increase, and when formed into a coating film, is less likely to sag with temperature increase. Means to resolve the solution

[0008] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a rust-preventive composition that is substantially free of wax and has a viscosity reduction rate of 25% or less at temperatures from 20°C to 80°C, and have thus completed the present invention.

[0009] The present invention may include the following: [1] A rust-preventive composition comprising a rust-preventive additive, bentonite, a filler, hardened oil, and a diluent, wherein the wax content is in the range of 0% by mass to 1% by mass, the rust-preventive additive content is in the range of 16% by mass to 35% by mass, the bentonite content is in the range of 2% by mass to 6% by mass, and the viscosity reduction rate from 20°C to 80°C is less than 25%. [2] The rust-preventive composition according to [1], which has a viscosity measured at 80°C of 10,000 mPa·s or more. [3] The rust-preventive composition according to [1] or [2], wherein the filler content is in the range of 5% by mass to 15% by mass. [4] The diluent has a kinematic viscosity measured at 40°C of 50 mm ２ / s or more 100mm ２ [5] An automobile part having a coating film comprising the rust-preventive composition according to any one of [1] to [4], wherein the rust-preventive composition has a viscosity of 1000 psi or less.

[0010] The present invention can provide a rust-preventive composition that has sufficient corrosion resistance, an excellent rate of viscosity reduction with increasing temperature, and when formed into a coating film, little sagging occurs with increasing temperature. It can also provide an automobile part having a rust-preventive coating film made of the rust-preventive composition.

[0011] A rust-preventive composition according to one embodiment of the present invention comprises (A) a rust-preventive additive, (B) bentonite, (C) a filler, (D) hardened oil, and (E) a diluent.

[0012] <(A) Rust-Preventive Additive> The rust-preventive additive may be any additive capable of imparting rust-preventive properties to the rust-preventive composition. Examples of such additives include sulfonates (such as alkylbenzenesulfonates, e.g., calcium salts), carboxylates (such as amine carboxylates), amine salts, fatty acid esters, oxidized paraffin salts, oxidized wax salts, mixtures of sulfonates and oils, mixtures of fatty acid esters and oils, and mixtures of oxidized paraffin salts and oils. Commercially available rust-preventive additives may also be used as they are. The rust-preventive additives may be used alone or in combination of two or more. The content of the rust-preventive additive is preferably in the range of 16% by mass to 35% by mass, more preferably 18% by mass to 30% by mass, based on the total amount of the rust-preventive composition.

[0013] <(B) Bentonite> Bentonite is a mineral primarily composed of montmorillonite, which has a layered structure consisting of stacked plate-like crystals of aluminosilicate. The particle size of the bentonite is preferably in the range of 0.1 μm to 10 μm, more preferably 1 μm to 5 μm. The particle size of the bentonite is the primary particle size. 20 random samples are extracted, and the particle sizes (major axes) of the extracted samples are measured using an electron microscope. The average value is taken as the particle size of the bentonite. The content of the bentonite is preferably in the range of 2% by mass to 6% by mass, more preferably 3% by mass to 6% by mass, based on the total rust-preventive composition.

[0014] <(C) Filler> Examples of fillers include calcium carbonate, kaolin clay, talc, mica, and various other conventionally known extender pigments. The particle size of the filler is not particularly limited, but is preferably in the range of 5 nm to 1000 nm, and more preferably in the range of 10 nm to 200 nm. The particle size of the filler is the primary particle size, and 20 random samples are extracted, the particle sizes (major axes) of the extracted samples are measured using an electron microscope, and the average value is taken as the particle size of the filler. The content of the filler is preferably in the range of 5 mass% to 15 mass% and more preferably in the range of 6 mass% to 12 mass% of the total rust-preventive composition.

[0015] <(D) Hydrogenated Oil> Examples of hydrogenated oils include natural drying oils such as linseed oil, perilla oil, tung oil, hemp seed oil, safflower oil, oiticica oil, sardine oil, and herring oil, as well as synthetic drying oils such as dehydrated castor oil. The hydrogenated oil preferably has an iodine value of 100 or more. One type of hydrogenated oil may be used alone, or two or more types may be mixed together. The content of the hydrogenated oil is not particularly limited, but is preferably in the range of 9% by mass to 15% by mass, and more preferably in the range of 9% by mass to 12% by mass, based on the total weight of the rust-preventive composition.

[0016] <(E) Diluent> The diluent is not particularly limited as long as it can be used as a base oil, and for example, mineral oil-based lubricating oils, synthetic lubricating oils, liquid saturated hydrocarbon mixtures, vegetable oil-based semi-drying oils, vegetable oil-based non-drying oils, etc. can be used. Specific examples of mineral oil-based lubricating oils include paraffinic lubricating oils and naphthenic lubricating oils, synthetic lubricating oils include esters, polyalphaolefins, polyalkylene glycols, polybutenes, alkyl diphenyl ethers, etc., liquid saturated hydrocarbon mixtures include liquid paraffin, vegetable oil-based semi-drying oils include soybean oil, cottonseed oil, rapeseed oil, rice oil, sesame oil, sunflower oil, corn oil, etc., and vegetable oil-based non-drying oils include olive oil, palm oil, peanut oil, camellia oil, etc. The diluent can be used alone or in combination of two or more.

[0017] The content of the diluent is not particularly limited, but is preferably in the range of 33% by mass to 60% by mass, and more preferably in the range of 50% by mass to 60% by mass, based on the total amount of the anticorrosive composition. ２ / s or more 100mm ２ / s or less, and ２ / s or more 80mm ２ / s or less. When the kinematic viscosity of the diluent is within the above range, the viscosity reduction rate of the rust preventive composition can be easily set within an appropriate range, and the occurrence of sagging can be suppressed. The kinematic viscosity of the diluent is a value measured by the measurement method specified in Clause 5 of JIS K 2283.

[0018] <(F) Wax> The rust-preventive composition according to one embodiment of the present invention is substantially free of wax. "Substantially free" means that the wax content is in the range of 0% by mass to 1% by mass relative to the entire rust-preventive composition. The wax content is more preferably in the range of 0% by mass to 0.5% by mass, and even more preferably in the range of 0% by mass to 0.1% by mass relative to the entire rust-preventive composition. Wax refers to various hydrocarbons or mixtures of various hydrocarbons that are solid or semi-solid at temperatures of 35°C or less. Examples of waxes include petroleum wax, vegetable oil-based wax, animal wax, mineral oil-based wax, and synthetic wax. Examples of petroleum waxes include paraffin wax, microcrystalline wax, and petrolatum. Examples of vegetable oil-based waxes include candelilla wax, carnauba wax, rice wax, Japan wax, and jojoba oil. Examples of animal-based waxes include beeswax, lanolin, and spermaceti. Examples of mineral oil-based waxes include montan wax, ozokerite, and ceresin. Examples of synthetic waxes include polyethylene waxes, polypropylene waxes, etc. The waxes may be contained alone or as a mixture of two or more kinds.

[0019] <Other Components> The rust-preventive composition may contain components (also referred to as "other components") other than the above (A) to (F) to the extent that the effects of the present invention are not impaired. Examples of other components include deodorants, fragrances, colorants, etc.

[0020] The present invention will be described in more detail below using examples, but the scope of the present invention is not limited to these examples.

[0021] <Preparation of Rust-Preventive Composition> The raw materials (mass%) shown in Table 1 were mixed, heated, and stirred. The mixture was then naturally cooled to obtain the rust-preventive compositions of Examples 1 to 10 and Comparative Examples 1 to 6. The symbols in Table 1 used in the preparation of the rust-preventive compositions refer to the following raw materials. The rust-preventive additive used was a commercially available mixture of sulfonate and oil, the hardened oil used was dehydrated polymerized castor oil, the filler used was calcium carbonate (particle size 80 nm), and the bentonite used was bentonite with a particle size of 0.1 to 1 μm. (E1) Mineral oil-based lubricating oil (kinematic viscosity at 40°C 55 mm ２ / s) (E2) Mineral oil-based lubricating oil (kinematic viscosity 75 mm at 40 ° C) ２ / s) (W1) Paraffin wax (W2) Microcrystalline wax

[0022] <Viscosity Decrease Rate> The viscosity was measured using a rheometer MCR102 manufactured by Anton Paar, with a PP25 plate (diameter 25 mm) and a gap of 1 mm, at a shear rate of 2 s －１ The viscosity was measured when the temperature was raised from 20°C to 80°C at a temperature rise rate of 0.08°C / s, and the viscosity reduction rate was calculated from the difference in viscosity between 20°C and 80°C. The viscosity reduction rate was then evaluated according to the following evaluation criteria. The results are shown in Table 1. A viscosity reduction rate of 25% or less was considered acceptable.

[0023]

[0024] <Evaluation of Rust Prevention> The rust prevention compositions of Examples 1 to 10 and Comparative Examples 1 to 6 were applied to a 70 x 150 x 0.8 mm cold-rolled steel plate (JIS G 3141 SPCC-SD) using a bar coater to a coating thickness of 50 μm, which had been dried after removing oil with a solvent (mineral spirits). After drying at room temperature for 72 hours, a neutral salt spray test was performed for up to 720 hours to measure the time until rust occurred. The rust prevention was then evaluated according to the following evaluation criteria. The results are shown in Table 2. A rating of "A" or higher was considered acceptable. S: No rust occurred after 720 hours A: 480 hours or more but less than 720 hours B: 240 hours or more but less than 480 hours

[0025] <Evaluation of Coating Retention During Application> Electrodeposition coated panels (manufactured by Paltec Co., Ltd.) measuring 70 x 150 x 0.8 mm were prepared. Oil was removed from these panels using a solvent (mineral spirits) and they were then dried. The lower half of the test specimen was masked, and the upper half was coated with the rust-preventive compositions of Examples 1 to 10 and Comparative Examples 1 to 6 using a bar coater. Starting with a minimum film thickness of 500 μm, the thickness was increased in 100 μm increments, up to a maximum of 1000 μm. Each coated panel was then unmasked and left perpendicular to the ground at room temperature for 1 hour. The thickness at which sagging occurred was confirmed, and coating retention was evaluated according to the following evaluation criteria. The results are shown in Table 2. A rating of "A" or higher was considered acceptable. S: No sagging of 1000 μm; A: 800 μm or more but less than 1000 μm; B: 700 μm or more but less than 800 μm; C: Less than 700 μm

[0026] <Evaluation of Coating Retention During Heating> Electrodeposition-coated panels (manufactured by Paltec Co., Ltd.) measuring 70 × 150 × 0.8 mm were prepared. Oil was removed from these panels using a solvent (mineral spirits) and they were then dried. The lower half of the test specimen was masked, and the upper half was coated with the rust-preventive compositions of Examples 1 to 10 and Comparative Examples 1 to 6 using a bar coater. Starting with a minimum film thickness of 500 μm, the thickness was increased in 100 μm increments, up to a maximum of 900 μm, to produce coated panels. After air-drying for 4 hours while horizontal to the ground, the masking was removed from each coated panel, and the panel was heated at 80°C for 30 minutes while vertical to the ground. The film thickness at which sagging occurred was confirmed, and coating retention was evaluated according to the following evaluation criteria. The results are shown in Table 2. A rating of "A" or higher was considered acceptable. S: No sagging of 900 μm A: 700 μm or more and less than 900 μm B: 400 μm or more and less than 700 μm C: Less than 400 μm

[0027] <Difference in Coating Film Retention Between When Applied and When Heated> Based on the results of the evaluation of coating film retention during application and the evaluation of coating film retention during heating, the difference in film thickness was evaluated according to the following evaluation criteria. The results are shown in Table 2. A rating of "A" or higher was considered acceptable. S: Less than 200 μm A: 200 μm or more and less than 300 μm B: 300 μm or more and less than 500 μm C: 500 μm or more

[0028]

Claims

1. A rust-preventive composition comprising a rust-preventive additive, bentonite, a filler, hardened oil and a diluent, wherein the wax content is within the range of 0 mass% or more and 1 mass% or less, the rust-preventive additive content is within the range of 16 mass% or more and 35 mass% or less, the bentonite content is within the range of 2 mass% or more and 6 mass% or less, and the viscosity reduction rate at 20°C to 80°C is 25% or less.

2. The rust-preventive composition according to claim 1, having a viscosity measured at 80°C of 10,000 mPa·s or more.

3. The rust-preventive composition according to claim 1 or 2, wherein the filler content is within the range of 5 mass % or more and 15 mass % or less.

4. The diluent has a kinetic viscosity of 50 mm measured at 40°C. ２ / s or more 100mm ２ The rust-preventive composition according to any one of claims 1 to 3, wherein the molar ratio of the anticorrosive agent to the anticorrosive agent is within the range of 0.1 to 0.

25.

5. An automobile part having a coating film containing the rust-preventive composition according to any one of claims 1 to 4.

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