JPH05156179A - Rust preventive composition for automotive underfloor - Google Patents

Abstract

PURPOSE:To provide the subject composition which has excellent application properties and can give a film excellent in corrosion and chipping resistances when applied to an automotive underfloor. CONSTITUTION:The objective composition comprises one or two members selected from waxes (e.g. microcrystalline wax) and asphalts (e.g. straight asphalt), one or two members selected from metal sulfonates (e.g. barium petroleum sulfonate liquor) and lanolin fatty acid/metal salts (e.g. calcium lanolinate liquor), an inorganic powder (e.g. talc), and an alkylbenzene with 8-20C alkyl, and the amount of the alkylbenzene is 0.5-30 pts.wt. per 100 pts.wt. total of the nonvolatiles of the composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust preventive composition for under-floor automobiles, and more specifically, it has excellent coating properties and corrosion resistance applied to under-floor automobiles, and peels off a film in chipping resistance at low temperature. The present invention relates to an underfloor rust preventive composition for automobiles.

[0002]

2. Description of the Related Art Anti-corrosion agents for under-floor automobiles are used in bad environments such as low temperatures (-30 to -20 ° C) in winter at high latitudes and high temperatures (60 to 80 ° C) near engine exhaust pipes. Even below
It is required to effectively exhibit its rust preventive power. For this reason, performances such as coatability for obtaining a uniform film, chipping resistance at low temperature, and sag resistance at high temperature are emphasized in rust preventive agents for under-floor automobiles. Then, as the rust preventive composition disclosed to satisfy the required performance, for example, a super basic alkaline earth metal sulfonate containing a fine powder of carbonate, petrolatum oxide or the like is mixed with an organic solvent. Composition (JP-A-61-111382), asphalt, metal salt of petroleum sulfonate, metal salt of petrolatum oxide, wax, microcrystalline wax,
A composition obtained by adding an extender pigment such as barium sulfate to lanolin fatty acid metal salt, synthetic sulfonic acid metal salt, etc.
189475).

[0003]

However, since the above-mentioned conventional rust preventive composition contains a large amount of inorganic powder, the coatability is poor when applied in a thin film under the floor of an automobile,
In addition, it also has the drawback of poor corrosion resistance. Further, there is a problem that the peeling area of the film is large even in the chipping resistance at low temperature. Therefore, the fact is that no under-floor rust preventive agent for automobiles, which sufficiently satisfies the coating property, the corrosion resistance and the chipping resistance, has been found.

The present invention has been made in view of the above-mentioned viewpoints, and provides an under-floor rust preventive composition for automobiles which is excellent in coating properties, corrosion resistance and chipping resistance when applied under the floor of an automobile. To aim.

[0005]

Means for Solving the Problems As a result of earnest studies on the component composition, coating properties and coating properties of rust preventive compositions, the present inventors have found that wax, asphalt, sulfonic acid metal salts, lanolin fatty acid metal salts, etc. The present invention has been found to be able to solve the above problems by adding a predetermined amount of alkylbenzene in a rust preventive composition in which a film component of talc and inorganic powder such as talc and calcium carbonate are combined as an extender pigment. It was completed. That is, the under-floor rust inhibitor composition of the present invention comprises 1 or 2 kinds selected from (a) wax and asphalt, and 1) selected from (b) sulfonic acid metal salt and lanolin fatty acid metal salt.
Or 2 kinds, (c) inorganic powder and (d) carbon atom number 8
The content of the above-mentioned (d) alkylbenzene is 100 parts by weight based on 100% by weight of the nonvolatile content of the rust preventive composition.
It is characterized by being 0.5 to 20 parts by weight. The content of alkylbenzene is determined in this way because if it is less than 0.5 part by weight, the corrosion resistance, coating property and chipping resistance at low temperature will be insufficient, while if it exceeds 20 parts by weight, the sagging resistance will decrease. is there.

Here, the above-mentioned "wax" includes animal and vegetable waxes such as beeswax, candelia wax, rice bran wax, and wax, paraffin wax, microcrystalline wax, mineral wax such as montan wax, polyethylene wax, polypropylene. Examples of the wax include synthetic waxes such as wax and Fischer-Tropsch wax. However, among these, it is preferable to use microcrystalline wax having a melting point of 40 to 90 ° C. In addition, as the above "asphalt",
Examples include natural asphalt such as rake asphalt and rock asphalt, and petroleum asphalt such as straight asphalt and blown asphalt. However, among these, it is preferable to use petroleum asphalt in consideration of compatibility with other components. The content of one or two components selected from the above (a) wax and asphalt is in the range of 10 to 80 parts by weight when the nonvolatile content of the entire rust preventive composition is 100 parts by weight. Preferably. This is because if the content is less than 10 parts by weight, the film strength is lowered and the corrosion resistance is poor, and if the content exceeds 80 parts by weight, the chipping resistance becomes insufficient.

Examples of the above-mentioned "metal salt of sulfonic acid" include metal salt of petroleum sulfonic acid and metal salt of synthetic sulfonic acid. Here, as the metal salt of petroleum sulfonic acid, a salt of an alkali metal or an alkaline earth metal obtained by purifying and neutralizing a sulfonic acid mixture of hydrocarbons, which is a by-product during the sulfuric acid refining of petroleum fractions, is used. Be done. Further, as the metal salt, sodium salt, calcium salt, barium salt and the like are preferable. The above-mentioned "lanolin fatty acid metal salt" is a metal salt of lanolin fatty acid obtained by decomposing and separating lanolin into a fatty acid portion and an alcohol portion by a method such as saponification decomposition and solvent extraction separation. As the metal salt, alkaline earth metals such as calcium and barium, aluminum, zinc and the like are preferable. The content of one or two components selected from the above (b) metal salt of sulfonic acid and metal salt of lanolin fatty acid is 10% by weight based on the entire nonvolatile content of the rust preventive agent.
When the amount is 0 part by weight, it is preferably in the range of 1 to 30 parts by weight. This is because if the content is less than 1 part by weight, the corrosion resistance decreases, and if the content exceeds 30 parts by weight, the sagging resistance decreases.

The above-mentioned "inorganic powder" is used as an extender pigment, and examples thereof include talc, calcium carbonate, diatomaceous earth, mica and kaolin. However, of these, it is preferable to use talc or calcium carbonate. The content of this inorganic powder is preferably in the range of 2 to 50 parts by weight when the total nonvolatile content of the rust preventive agent is 100 parts by weight. This is because if the content is less than 2 parts by weight, the anti-dripping property is insufficient, and if the content exceeds 50 parts by weight, the corrosion resistance decreases.

The above-mentioned "alkylbenzene" is a compound synthesized by reacting benzene with an alkylating agent such as n-olefin and propylene tetramer, and an alkyl group having 8 to 20 carbon atoms is used. This is because when the number of atoms is less than 8, it is not preferable because the boiling point is low and the evaporation loss is large, and when it exceeds 20, the solubility of the organic solvent is poor, which is not preferable. However, among these,
Those having 10 to 14 carbon atoms are preferable. Further, the alkyl group is preferably a linear soft type. This is because the pour point is low and the chipping resistance at low temperature is excellent.

In addition to the above-mentioned essential components, the rust preventive agent for under-floor automobiles of the present invention has the purpose of adjusting the hardness of the coating, coloring the coating, preventing deterioration of the coating with time, adjusting the viscosity during coating, etc. A resin, a mineral oil, a color pigment, an ultraviolet absorber, an antioxidant, a plasticizer, an organic solvent, an anti-sagging agent and the like can be appropriately contained. Further, the use of the rust inhibitor composition of the present invention,
For example, an airless spray coating machine (discharge pressure 40 to 150
Kgf / cm ² ) or the like, for example, by spray coating.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these Examples and Comparative Examples. (1) Preparation of Anticorrosion Agent Composition Table 1 shows compositions relating to the examples of the present invention, and Table 2 shows compositions of comparative examples.

[0012]

[Table 1]

[0013]

[Table 2]

The numerical values relating to the composition of the components in each table are parts by weight unless otherwise specified. In addition, "wax" in each table means microcrystalline wax (melting point; 78
° C) and "asphalt" means straight asphalt (softening point; 78 ° C, penetration; 193 at 25 ° C).
Furthermore, "Petroleum Sulfonate Sulfate Liquid" and "Synthetic Barium Sulfonate Liquid" in the table are mineral oil diluted products, and "Synthetic Calcium Sulfonate Liquid" and "Lanoline Fatty Acid Calcium Liquid" in the same table are mineral spirit diluted products. Is. And in each case, the active ingredient is contained in a ratio of 50 parts by weight when the whole diluted product is 100 parts by weight. Further, the average particle size of "talc" in the table is 2 μm, and the oil absorption is 1
52g against 00g, "Lucium carbonate" in the table
Has an average particle size of 2 μm and oil absorption of 60 g per 100 g
Is. Further, the “alkylbenzene” in the table has a linear alkyl group having 10 to 14 carbon atoms [kinematic viscosity: 5 mm ² / s (40 ° C.), pour point: −70].
[° C], and as "mineral oil", machine oil [kinematic viscosity;
260 mm ² / s (40 ° C., pour point; −15 ° C.] was used.

The "antioxidant" in the table is a phenolic antioxidant (2,6-tert-dibutyl-p).
-Cresol) and an oxidized polyethylene-based anti-sag agent was used as the "anti-sag agent." Further, as "mineral spirit" in the table, the boiling point is 150 to 19
The one having 0 ° C. and the aniline point of 55 ° C. was used. In addition, “nonvolatile matter (wt%)” in the same table refers to parts by weight of non volatile matter contained in the composition when the total amount of each composition is 100 parts by weight (hereinafter, also referred to as “wt%”). ), JIS K
It is measured according to 4 of 5400. Furthermore, "weight% of alkylbenzene" in the same table refers to weight parts of alkylbenzene contained therein (hereinafter also referred to as "weight%") when the total nonvolatile content contained in each composition is 100 parts. .) According to JIS K5400-4.

(2) Performance Test In order to clarify the performance of the under-floor rust preventive agent of the present invention, a performance evaluation test was conducted on the compositions shown in Tables 1 and 2. The test items and test conditions are described below. Viscosity B type rotary viscometer, No. 6 rotor, 20 rp
The viscosity at 20 ° C. was measured in m. Applicability Airless spray coating machine (Nippon Gray Co., Ltd., Bulldog type, compression ratio 30: 1) and nozzle tip 163-4
17 (manufactured by Nippon Gray Co., Ltd., caliber 0.43 mm) at a discharge pressure of 50 kgf / cm ² and a dry film thickness of 50 μm.
The atomized state and the film state when coated so as to have a thickness of m were evaluated. Corrosion resistance test piece (SPCC-SD, 150 x 70 x 0.8 mm)
Spray coating to give a dry film thickness of 50 μm, and after drying at room temperature for 24 hours, salt spray test (JISK22
46) was evaluated by the rust generation area when tested for 1000 hours.

Chipping resistance Electrodeposition coated plate (150 × 70 × 0.8 mm) was spray-coated so as to have a dry film thickness of 200 μm, dried at room temperature for 72 hours, and then kept at −30 ° C. for 3 hours. Then, using a stepping stone tester (manufactured by Suga Tester, model JA-400), 6
The peeled area of the film was measured when one shot of 500 g of crushed stone No. 1 was shot at a jet pressure of 5 kgf / cm ² . Anti-dripping property The lower half (75 mm) of the electrodeposition coated plate (150 × 70 × 0.8 mm) is masked, spray-coated to a dry film thickness of 200 μm, and dried at room temperature for 75 hours, then masked. The length of the sag when measured after being detached and suspended at 80 ° C. for 24 hours was measured.

(3) Results of Performance Test and Evaluation thereof Results of Performance Test Table 3 shows the results of the above performance test.

[0019]

[Table 3]

However, the unit of viscosity in the table is mPa · s, and the weight% of alkylbenzene is shown in Tables 1 and 2.
Is the same as. Further, the significance of the display of evaluation in the table is as follows. That is, in the "coating property", "○" means "good", "△" means "slightly tailed and slightly scaled", and "x" means "significant tailed, markedly noticeable". Also, ○ in "corrosion resistance" means "no rust"
△ means “less than 10% rust generation”, × means “rust generation 10%”
Or more ”. Further, in the "chipping resistance", "○" means "peeling area less than 5%" and "△" means "peeling area 5 to 5".
20% ", x represents" peeling area 20% or more ". In addition, ○ in "stop dripping" means "no dripping"
, △ is "drip length less than 10 mm", x is "drip length 1
0 mm or more ". Performance Evaluation According to the above performance test, the rust preventive agent compositions according to Examples 1 to 6 show stable viscosity values as compared with conventional products. Further, Comparative Examples 1 and 3 in coating property, Comparative Example 2 in corrosion resistance, Comparative Examples 1 to 3 in chipping resistance, and Comparative Examples 4 and 5 in sagging resistance showed poor results. .. On the other hand, the composition of this example satisfies all the properties of coating property, corrosion resistance, chipping resistance, and sagging resistance.

[0021]

INDUSTRIAL APPLICABILITY As described above, the anticorrosive agent for underfloor of an automobile of the present invention is excellent in coating property, corrosion resistance and chipping resistance at low temperature, so that it can be applied uniformly as a thin film. Further, even under a bad environment, it is possible to exert a rust preventive effect for a long period of time.

Claims (1)

[Claims] 1. An (a) one or two selected from wax and asphalt, (b) one or two selected from a sulfonic acid metal salt and a lanolin fatty acid metal salt, (c) an inorganic powder and (d). ) An alkylbenzene having an alkyl group having 8 to 20 carbon atoms is contained, and the content of the above (d) alkylbenzene is 0.5 when the total nonvolatile content of the rust preventive composition is 100 parts by weight.
A rust preventive composition for an underfloor of an automobile, characterized in that it is from 20 parts by weight.