JP2551448B2 - Metal sheet having solid lubricant and solid lubricating layer - Google Patents

Description

The present invention relates to a solid lubricant for press forming or the like and a surface-treated metal thin plate having this solid lubricating layer, and is applied to a thin steel plate, a thin aluminum plate or the like. It gives good lubricity during press molding and has excellent rust resistance before and after pressing.
In addition, since the lubricating film is water-soluble or water-dispersible, it is a metal thin plate having a solid lubricant and a solid lubricating layer, which has the property of being completely dissolved in the pretreatment process of a chemical conversion treatment line such as automobile and household electric appliance manufacturing. is there.

[Conventional technology]

In the case of performing deep drawing or other press forming on thin plates, particularly steel plates, a method of applying a lubricating oil containing a mineral oil as a base oil immediately before pressing has been generally adopted. This oil coating process is a significant obstacle to improving press efficiency, and is one of the causes of degreasing load in the post-treatment process, deterioration of the working environment of the press process, and troubles in welding work in the assembly process. There is. Recently, with the introduction of high-speed continuous presses, the temperature of press dies and punches has risen remarkably, and press cracks due to seizure have frequently occurred. We are advancing in a severe direction toward molding.

For such a situation, for example, Japanese Patent Publication No. 44-2017, 44
In the publications such as -16774 and 58-65793, the wax-like substances solidified at room temperature (including semi-solid ones at room temperature), which have good lubricity and excellent rust resistance, are pre-formed by the steel sheet manufacturer. Applying it to the surface not only satisfies the best lubrication conditions, but also eliminates the need for coating immediately before pressing, thus improving the productivity and reducing the number of personnel on both the steel plate manufacturer side and the press installer side. Although it is proposed to be large, rust resistance, pressability and degreasing property are not sufficiently satisfied by these techniques. In other words, the recent technological direction of energy saving and cost saving is rapid, and the conventional quality is not satisfied, and taking degreasing property as an example, the degreasing bath has a lower temperature, a lower concentration, and a shorter time. It is necessary to double the degreasing property.

[Problems to be Solved by the Invention]

From this viewpoint, the present inventor has invented a method of forming a film composed of a water-soluble linear polymer (particularly polyethylene oxide) and a water-soluble rust preventive agent on the surface of a steel sheet in Japanese Patent Application No. 61-258160. And succeeded in developing a lubricated steel sheet with excellent press formability and degreasing property. However, this method has the following problems.

First of all, the first point is that the coating of the lubricating steel sheet is soft, and when the surface of the steel sheet at a specific temperature comes into contact with a roll in a production line where the coating is applied on the steel sheet and dried, the coating partially peels off or adheres to the roll surface. It is easy to cause problems such as
The second point is that polyethylene oxide has strong water absorption,
Even if a water-soluble rust preventive agent is added and a rust preventive oil film layer is formed on the film surface, the rust resistance is low.

The present invention improves these points and provides a metal thin plate having a more excellent high lubricity solid lubricant and solid lubrication layer, and a water-soluble or water-dispersible film forming component (hereinafter referred to as a water-soluble film agent). Particularly, by using polyethylene glycol and an organic polymer compound having a carboxylic acid group, the above-mentioned drawbacks can be solved while maintaining excellent press moldability and degreasing property.

[Means for solving the problem]

The gist of the present invention is that a water-soluble rust preventive agent 0.5 to 40w
A solid lubricant containing t% and the balance being a water-soluble coating agent, and a metal thin plate on which a coating of this solid lubricating layer is formed at 0.5 to 5 g / m ² on one side has a molecular weight of 10 as the water-soluble coating agent.
Mainly polyethylene glycol of 00 or more, molecular weight 1000
The above is a specific composition using a polymer compound having a carboxylic acid group having a molecular weight of 50 to 4000 per carboxylic acid, and the details are as follows.

That is, the water-soluble rust preventive agent is 0.5 to 40 wt%, and the rest has a molecular weight of 1000.
An organic polymer compound having a carboxylic acid group and / or a salt thereof (B) having the above polyethylene glycol (A) and a molecular weight of 1000 or more and a molecular weight of 50 to 4000 per carboxylic acid
And a water-soluble or water-dispersible film-forming component, wherein the water-soluble or water-dispersible film-forming component is polyethylene glycol (A).
0.5 to 100 parts by weight of the organic polymer compound and / or its salt (B) per 100 parts by weight, and the organic polymer compound is a polymer and / or copolymer of unsaturated carboxylic acid, The copolymer comprises unsaturated carboxylic acid and ethylene and / or unsaturated carboxylic acid ester, the unsaturated carboxylic acid is acrylic acid and / or methacrylic acid, and the copolymer is acrylic acid and / or methacrylic acid. And ethylene, and the salt is at least one selected from the group consisting of alkali metal salts, ammonium salts and organic amine salts.

Furthermore, water-soluble rust preventive agent 0.5-40wt%, the rest is molecular weight 1000
Water-soluble or water-dispersible film comprising the above-mentioned polyethylene glycol (A) and an organic polymer compound having a carboxylic acid group and / or a salt thereof (B) having a molecular weight of 1000 or more and a molecular weight of 50 to 4000 per carboxylic acid A metal thin plate having a solid lubricating layer as a forming component of 0.5 to 5 g / m ² on one side, and a water-soluble or water-dispersible film forming component per 100 parts by weight of polyethylene glycol (A). The organic polymer compound and / or its salt (B) is 0.5
To 100 parts by weight, and the organic polymer compound and / or its salt (B) is a polymer and / or copolymer of an unsaturated carboxylic acid.

In the present invention, the thin plate means a cold rolled steel plate, Zn
It refers to a plated steel sheet such as the above, a vibration-damping steel sheet, a resin composite steel sheet such as a laminated steel sheet, or those obtained by subjecting these to chemical conversion treatment, coating, etc., and a similar thin plate of non-ferrous metal such as aluminum is also included in the range.

Further, the water-soluble rust preventive agent contains 1-hydroxybenzotriazole compound as a main component and contains 1 to 2 of fatty acid dicarboxylic acid.
Seeds and an aqueous solution having a pH of 7 to 8 and optionally a surfactant (disclosed in Japanese Patent Publication No. 59-22793),
Other known aqueous solution rust inhibitors such as sodium sulfite, sodium nitrate, aromatic carboxylic acids, imidazoles,
It refers to a combination of amino acids, a surfactant and the like.

Next, the details of the water-soluble film forming agent mainly composed of polyethylene glycol specified in the present invention will be described.

In the present invention, the molecular weight of polyethylene glycol (A) having a molecular weight of 1000 or more is usually 1000 to 40,000 or more, preferably 2000 to 30,000. Further, (A) may be modified, and as modification, copolymerization with other alkylene oxides (having 3 to 4 carbon atoms) (ratio of ethylene oxide is 80% by weight or more) and alkyl of terminal hydroxyl group (having carbon number) 1-4) Etherification, alkyl (C1-C1)
2) Examples include esterification.

The organic polymer compound having a carboxylic acid group is usually a (co) polymer of a polymerizable monomer having a carboxylic acid group, a polymerizable monomer having a carboxylic acid group and another polymerizable monomer. A copolymer of the body, an organic polymer compound having a carboxylic acid group introduced by modification such as hydrolysis or oxidation, and the like can be used. As the method for producing the (co) polymer, methods such as radical polymerization, ionic polymerization and condensation can be usually used.

The molecular weight of (B) is usually 1000 to 100,000 or more, preferably 2000 to 500000. The molecular weight per carboxylic acid is usually 50 to 4000, preferably 60 to 2000.

The unsaturated carboxylic acid is an unsaturated monocarboxylic acid, for example, (meth) acrylic acid [(meth) acrylic acid means acrylic acid and / or methacrylic acid. The same applies hereinafter] and crotonic acid; unsaturated polycarboxylic acids such as maleic acid. Unsaturated monocarboxylic acids are preferred, and (meth) acrylic acid is particularly preferred.

Examples of unsaturated carboxylic acid esters include alkyl esters of unsaturated monocarboxylic acids (wherein the alkyl group has 1 to 18 carbon atoms) (methyl, ethyl, butyl, 2-ethylhexyl, octyl esters of the above unsaturated monocarboxylic acids, etc.), Examples thereof include hydroxyalkyl esters of unsaturated monocarboxylic acids (the carbon number of the alkyl group is usually 2 to 4) [hydroxyethyl (meth) acrylate, etc.]. Preferred is an alkyl ester of (meth) acrylic acid having 1 to 4 carbon atoms.

The copolymer may have other vinyl monomers in addition to unsaturated carboxylic acid, ethylene and unsaturated carboxylic acid ester, and examples of the other vinyl monomer include aliphatic vinyl hydrocarbon monomer. Examples include polymers (propylene, butene, etc.), aromatic vinyl hydrocarbon monomers (styrene, α-methylstyrene, etc.), carboxylic acid vinyl esters (vinyl acetate, etc.) and two or more of these.

 Examples of the copolymer include the following.

Acrylic acid (20) -Ethylene (72) -Ethyl acrylate (8) copolymer Acrylic acid (20) -Ethylene (80) copolymer Acrylic acid (7) -Methyl methacrylate (55) -Acrylic acid Butyl (38) Copolymer Methacrylic Acid (15) -Methyl Methacrylate (40) -Butyl Acrylate (30) -Styrene (15) Copolymer Acrylic Acid (60) -Methyl Methacrylate (20) -Ethyl Acrylate (20) Copolymer (Note) The figures in parentheses above are% based on the weight of the copolymer.
Indicates.

The (co) polymer of unsaturated monocarboxylic acid can be produced by a usual radical polymerization method such as a solution polymerization method, a non-solution polymerization method and an emulsion polymerization method.

 Examples of alkali metals include Li, Na and K.

As the organic amine, alkyl (the carbon number of the alkyl group is usually 1 to 10) amine (ethylamine, butylamine,
Cyclohexylamine, etc., alkanolamines (mono.di.triethanolamine, monoisopropanolamine, diethanolcyclohexylamine, etc.), dimethylethanolamine, morpholine, etc.

Of the alkali metal salts, ammonium salts and organic amine salts, the alkali metal salts are preferred. Particularly preferred are Na and K.

The details of the solid lubricant in the present invention are as follows. Next, the necessity of the water-soluble rust preventive agent will be further described.

In the present invention, it has already been described that a solid lubricant having a water-soluble coating agent mainly composed of polyethylene glycol is applied to the surface of a thin metal plate.However, polyethylene glycol, which is a component of these water-soluble coating agents, reduces the molecular weight and absorbs moisture. The corrosion resistance of the thin metal plate is reduced, and when it is applied to the surface of the thin metal plate, moisture absorption naturally lowers the rust resistance. Therefore, it was possible to impart rust prevention by using a water-soluble rust preventive agent when dissolving the water-soluble film forming agent in water. Moreover, the reason why the addition ratio of the water-soluble rust preventive agent is limited to 0.5% to 40% of the water-soluble film forming agent is that the rust preventive property is lowered when it is less than 0.5%, and the lubricity is lowered when it exceeds 40%. This is because.

If the molecular weight of polyethylene glycol is less than 1000, press moldability is insufficient, and therefore, it is usually 1000 to 40,000 or more. When the molecular weight increases, the solubility and degreasing property tend to decrease, and it is preferably 2000 to 30,000.

If the molecular weight of (B) is less than 1000, the film adhesion is insufficient, so that it is usually 1000 to 100,000 or more. When the molecular weight increases, the solubility and degreasing property tend to decrease, and it is preferably 2000-500000.

When the molecular weight per carboxylic acid exceeds 4000, the solubility and degreasing property are insufficient, so it is usually 50 to 4000, or 50
If the amount is less than 60%, the rust preventive property is insufficient, and it is preferably between 60 and 2000.

The solid lubricant is solidified at room temperature. To form a thin film on a thin metal plate, dissolve it in water at a concentration of 0.5% to 12% (concentration changes depending on the dry film thickness), and use a spray method or a grooved roll to coat the roll coater. It is desirable to dry with hot air of 100 ° C or higher immediately after coating. The dry film thickness should have a lower limit of 0.5 g / m ² to ensure rust prevention and press formability effects, and above 5.0 g / m ² for weldability, blocking properties, slip properties, degreasing properties, etc. This is the upper limit because it deteriorates.

The coating of the present invention can be applied to both sides of the thin plate with the same or different thickness, and may be applied to only one side of the thin plate, and the other side may be untreated without forming a coating.

In the present invention, a generally used rust preventive oil film layer may be formed on the outermost surface according to the intended use, and it is effective especially when high rust resistance is required.

〔Example〕

 Next, examples of the present invention will be described.

[Example 1] The water-soluble coating agent mainly composed of polyethylene glycol shown in Table 1 No. 1 to No. 10 was 5 to 15 wt% as solid content,
Further, a water-soluble rust preventive agent (disclosed in Japanese Patent Publication No. 59-22793) is contained in an amount of 0.5 to 10% by weight, and the balance is composed of water.
After applying the aqueous solution of No. 8 on both sides of a low-carbon cold-rolled steel sheet having a thickness of 1.2 mm by using a roll coater, it is dried using an induction heating method or a hot air circulation type heating furnace, and a solid of 1.5 to ² g / m ² per one side. A lubricating film was formed. Then, an ordinary mineral oil-based rust preventive oil was applied to both sides of the steel sheet in an amount of 1 to 1.5 g / m ² per side, and the following evaluation tests (A) to (E) were carried out.

(A) Press formability (laboratory evaluation) A specimen with a blank diameter of 250 mm x 25 mm was cut out from this steel sheet and wrinkle holding pressure of 5 t / cm ² was used to draw a 100 mm square tube to a depth of 25 mm to check for cracks. After the investigation, the wrinkle presser pressure was increased to 10 t / cm ² for those without cracks, and the pressure was reduced to a depth of 90 mm. The evaluation was carried out by visually observing the drawing depth (mm), the necking state of the corner portion, and the surface flaw of the die contact surface.

 The press oil was tested under the condition that no oil was applied.

(B) Press Formability (Oil Pan Press Formability) Part of this steel plate was tested to be processed into an oil pan that is an engine part of an actual car. Two types of oil pans were selected for small cars (1500cc) and large cars (3000cc). The evaluation was carried out in the same manner as in the item (A), and the overall evaluation was displayed in four grades of ⊚, ◯, Δ, and ×.

(C) Rust resistance A 70 × 150 mm test piece was cut out from a steel plate, left for 7 days in an environment of a temperature of 50 ° C. and a relative humidity of 95%, and the surface rusting condition was visually evaluated. The evaluation criteria are ◎: No rusting, ○:
Area ratio 0.1% or less rust, △: Area ratio 0.1 ~
1% rust, x: There were 4 levels of area ratio of 1% or more rust.

(D) Degreasing and chemical conversion treatability A sample similar to the item (C) is surface-degreased by using a commercially available degreasing agent and then surface activated to form a commercially available dip-type chemical conversion treatment film. The condition of the chemical conversion coating was visually evaluated. The evaluation was carried out in four stages of ◎, ○, △, ×, with the steel plate obtained by applying the rust preventive oil shown in Example 1 on a low carbon cold rolled steel plate having a thickness of 1.2 mm as a reference.

(E) Film Adhesion Test A 300 × 500 mm test piece was cut out from a steel plate, and the test piece was passed through an ordinary 5-stage roll leveler. After that, the film state on the surface of the steel sheet was visually evaluated in the following four stages. ◎: No film peeling, ○: Minute film peeling, △: Film peeling 5 to 20% (area ratio to the entire surface), ×: Film peeling 20% or more [Example 2] A polyisobutylene resin is sandwiched between two low-carbon cold-rolled steel sheets having a thickness of 0.6 mm to form a vibration-damping steel sheet, and the other items are the same as in Example 1.

However, the resin used was only No. 9 and 10 of Example 1,
Further, the evaluation test was limited to the item (B) of Example 1.

[Embodiment 3] In Embodiment 1, the solid lubricating coating is formed on only one side of the steel sheet, and the other items are the same as those in Embodiment 1.

However, the resins used were only No. 9 and No. 10 of Example 1. Further, the evaluation test was carried out only for the item (B) of Example 1, and the surface on which the solid lubricant film was formed was the die side (wrinkle holding side) during the press working.

[Conventional example 1] An aqueous solution having a pH of 7 to 9 containing polyethylene glycol having a molecular weight of 20000 as a solid content and 10 wt% of a water-soluble rust preventive agent as the solid content, and the balance being water, was applied to both sides of the same steel sheet. ,
The same amount was applied by the same method to form a solid lubricating coating. Subsequently, the same rust preventive oil as in Example 1 was applied in the same manner.

[Conventional Example 2] Using the same cold-rolled steel sheet as in Example 1, (1) untreated,
(2) Apply only rust preventive oil on both sides as in Example 1.
Four types of (3) Millbond (manufactured by NOF Corporation) and (4) LUBCOAT (manufactured by Nippon Machine Oil Co., Ltd.) were prepared and evaluated. The test pieces (3) and (4) were manufactured according to the standard specifications of the drug manufacturer, and only the item (A) of Example 1 was evaluated.
The test pieces (1) and (2) were evaluated for all the items (A) to (D) of Example 1.

The evaluation test results of the examples of the present invention and the comparative examples are shown in the second
Shown in the table. It is understood that the examples of the present invention show excellent properties in all items, and depending on the press forming conditions, it may be advantageous to form the solid circulation coating on only one side of the steel sheet.

〔The invention's effect〕

As described above, the solid lubricant according to the present invention exhibits excellent high lubricity, anticorrosiveness, and water solubility with respect to a metal thin plate, and a metal thin plate having such a solid lubricant layer is used in press, oil pan, etc. Excellent moldability, rust resistance,
It has excellent degreasing / chemical conversion treatment and film adhesion, and can save the labor such as pre-treatment at the time of processing, can also be made into small parts of processed products, and can be applied to difficult-to-form products, and can improve productivity. It is a thing.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C10M 145: 14) C10N 30:06 30:12 40:24 50:02 (72) Inventor Takeshi Yamada 1-11 Sanyo Kasei Kogyo Co., Ltd., 1 Hitotsubashi Honcho, Higashiyama-ku, Kyoto, Kyoto Prefecture (72) Inventor Tomio Kawauchi 1-11 San-ichi Kasei Co., Ltd., Hitotsubashi-Honcho, Higashiyama-ku, Kyoto Prefecture, Kyoto Prefecture

Claims (10)

(57) [Claims] 1. A water-soluble rust preventive of 0.5 to 40 wt%, and the balance of polyethylene glycol (A) having a molecular weight of 1000 or more
1000 or more and the molecular weight per carboxylic acid is 50 to 4000,
A solid lubricant, which is a water-soluble or water-dispersible film-forming component comprising an organic polymer compound having a carboxylic acid group and / or its salt (B). 2. A water-soluble or water-dispersible film-forming component comprises 0.5 to 100 parts by weight of an organic polymer compound and / or its salt (B) per 100 parts by weight of polyethylene glycol (A). The solid lubricant described. 3. The solid lubricant according to claim 1, wherein the organic polymer compound is a polymer and / or copolymer of unsaturated carboxylic acid. 4. A copolymer comprising an unsaturated carboxylic acid and ethylene and / or an unsaturated carboxylic acid ester.
The solid lubricant described. 5. The solid lubricant according to claim 3, wherein the unsaturated carboxylic acid is acrylic acid and / or methacrylic acid. 6. The solid lubricant according to claim 3, wherein the copolymer is a copolymer of acrylic acid and / or methacrylic acid and ethylene. 7. The solid lubricant according to claim 1, wherein the salt is at least one selected from the group consisting of alkali metal salts, ammonium salts and organic amine salts. 8. A water-soluble rust preventive agent of 0.5 to 40 wt%, the balance being a molecular weight of 1
000 or more polyethylene glycol (A) and molecular weight 1000
A solid lubricating layer which is a water-soluble or water-dispersible film-forming component composed of an organic polymer compound having a carboxylic acid group and / or a salt thereof (B) and having a molecular weight of 50 to 4000 per carboxylic acid A thin metal plate having a solid lubricating layer of 0.5 to 5 g / m ² per unit. 9. A water-soluble or water-dispersible film-forming component comprises 0.5 to 100 parts by weight of an organic polymer compound and / or its salt (B) per 100 parts by weight of polyethylene glycol (A). A metal sheet having a solid lubricating layer as described. 10. A thin metal plate having a solid lubricating layer according to claim 8 or 9, wherein the organic polymer compound and / or its salt (B) is a polymer and / or copolymer of an unsaturated carboxylic acid.