JPH10114014A - Surface lubricating treatment steel sheet with excellent marring resistance and film-removing property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stainless steel sheet having such a lubricating treatment film on the surface that the stainless steel sheet is substituted for a conventional stainless steel sheet laminated with a vinyl sheet and performance such as marring resistance, lubricating properties and film-removing properties necessary at time of plastic working is satisfied. SOLUTION: Water-based treating liquid is applied to the surface of a stainless steel sheet in which surface roughness Ra is <=0.15μm and dried to form such a lubricating treatment film that film thickness is 0.5-10μm and the average inclination angle (Αa) of unevennesses on the surface is <=2.62×10<-2> . The water- based treating liquid contains at least one kind of resin, which has glass transition temperature of 10-85 deg.C and is water-soluble or water-dispersible or alkali- soluble, and contains <=5.0wt.% silane coupling agent for the alkali-soluble resin solid content and 0.5-10wt.% metallic soap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a stainless steel sheet having a lubricated film excellent in scratch resistance and film removal property on a surface of a base stainless steel sheet (hereinafter referred to as a surface lubricated stainless steel sheet). .

[0002]

2. Description of the Related Art When a metal plate such as a steel plate is subjected to plastic working, a lubricating agent such as a press oil is applied to the metal plate before the working to improve the lubricity between the mold and the metal plate. Techniques for reducing the applied load and preventing seizure have been conventionally employed.

However, in recent years, in consideration of environmental problems in applying lubricant and removing the lubricant after processing, and in consideration of reduction of manufacturing cost, a consumer does not apply lubricant at the time of processing. At the metal plate manufacturing stage or at an appropriate stage up to the customer, a solid organic film containing various lubricants in the organic resin (referred to as “lubrication treatment film” in this specification) is applied to the surface of the metal plate in advance. The formed surface lubricated metal plate has come to be widely used. As a result, the consumer can immediately perform the plastic working, which saves labor.
Another advantage is that the quality of the lubricated coating formed is stabilized and homogenized, since the application of the lubricant is carried out on a large scale in specialized equipment.

[0004] Surface lubrication-treated metal plates are roughly classified into a film-deposited type and a non-film-deposited type. After removing the lubricated film by a method such as degreasing after plastic working,
It is used as it is without any treatment or after further chemical conversion treatment and painting. On the other hand, a non-delamination type surface lubricated metal sheet is used without removing the lubricated film after plastic working, with the lubricated film attached, or with further coating applied thereon. In the case of a metal plate with a beautiful surface, such as a brightly annealed stainless steel plate,
In order to make the final product by taking advantage of its beautiful surface, it is often used as a film-deposited surface lubricated metal plate.

[0005] The main performance required of a delamination type lubricating film for plastic working is described below. Good lubricity even when the film thickness is small. After the film is formed, the films do not easily stick to each other (good blocking resistance). The film can be easily removed by washing.

An acrylic resin, a processing liquid capable of forming such a lubricating film on the surface of a metal plate,
The main component is a dry or bake-curable film-forming component composed of a conventionally known water-soluble or water-dispersible resin such as an epoxy resin, a melamine resin, or a phenolic resin. One or two of soap, fatty acid ester, fatty acid amide, higher alcohol, graphite, molybdenum disulfide, fluororesin powder, etc.
Compounds containing more than one kind of lubricating component have been proposed.

[0007]

In the case of a metal plate having a metallic luster on its surface such as a brightly annealed stainless steel plate, it is not sufficient to provide lubricity that enables severe plastic working such as drawing. In addition, it is required to maintain the original beautiful surface even after removing the lubrication film after processing. This is because if the metal plate of the base material is scratched during processing, the beautifulness of the surface is greatly impaired. Therefore, the lubricating coating is required to have sufficient scratch resistance to prevent scratching of the base metal plate during processing.

However, the conventional lubricating film described above is
It does not have such scratch resistance. Therefore, in the plastic working of the bright annealed stainless steel sheet, instead of forming the lubrication treatment film as described above, a vinyl film or the like having a thickness of about 80 μm is stuck to the surface of the stainless steel sheet before processing to obtain lubricity and beautifulness. Generally, a method for securing a proper surface is adopted.

However, in this method, an operation of peeling the film after the plastic working is required, and since this operation can be usually performed only by human power, it greatly hinders automation and labor saving of the production line and raises the cost. . In addition, it is often difficult to peel the film particularly at the processed part. Furthermore, the peeled film is bulky and difficult to incinerate in many cases, and requires a great deal of expense for volume reduction and landfill treatment.

[0010] For this reason, there has been a strong demand for the improvement of scratch resistance of a film-coated surface lubricated metal sheet. In this regard, for example, Japanese Patent Application Laid-Open No. Sho 52-104459 discloses that for processing, an organic resin film having a specific composition is provided on both sides, and a lubricating film is further formed thereon on one side on which plastic working is performed. A stainless steel plate is disclosed. JP-A-53-75159 discloses a stainless steel sheet whose surface is coated with a vinyl resin or the like having a specific acid value and a glass transition temperature. However, at present, there is no stainless steel sheet having a lubricated film having a very high scratch resistance required by a consumer such as a home appliance manufacturer.

In view of such a situation, the present invention satisfies all the performances required for a lubricating film for plastic working, such as scratch resistance, lubricating properties, film removing properties, etc.
It is an object of the present invention to provide a surface-lubricated stainless steel sheet of a film removal type.

[0012]

Heretofore, the main idea for preventing surface flaws generated during plastic working has been as follows.

(A) The thickness of the lubricating film is increased to avoid direct contact between the mold and the metal plate.

(B) The lubricating property of the lubricating film is improved by adding a solid lubricant or the like, and the sliding length up to the occurrence of scratches is increased.

However, with a lubricating film based on such a concept, it is difficult to reliably prevent the occurrence of surface flaws on the base metal if the conditions of the plastic working are severe. Therefore,
The present inventors have conducted various studies on the mechanism of surface flaw generation during plastic working, and as a result, the peeled pieces of the lubricating film deposited in the mold due to contact with the material themselves cause surface flaws I determined that.

That is, no matter how thick the film having good lubricity is formed on the surface of the base metal, if the adhesion between the film and the base metal is low, the film is exfoliated and the peeled film is deposited on the mold. Cause surface scratches. Therefore, it was concluded that the generation of surface flaws can be suppressed by increasing the adhesion between the film and the base metal.

Based on this finding, the present inventors have conducted repeated studies on the main components and additives of the resin constituting the delaminated lubricating film, and have found that the conventionally proposed resin component and lubricity In addition to the components, a silane coupling agent is added to enhance the adhesion between the lubricated coating and the base metal, resulting in a dramatic improvement in scratch resistance and good film removal. Can be formed on stainless steel.

Here, the present invention provides a stainless steel plate having a surface roughness of Ra ≦ 0.15 μm having a glass transition temperature of 10
At least one kind of water-soluble or water-dispersible alkali-soluble resin having a temperature of not less than 85 ° C and not more than 5.0% by weight and a silane coupling agent of not more than 0.5% by weight and not more than 10% by weight based on the solid content of the alkali-soluble resin; Film thickness of 0.5 μm or more formed from an aqueous treatment solution containing
μm or less, the average inclination angle (Δa) of surface irregularities is 2.62 × 10
^{This is} a surface lubricated stainless steel sheet with excellent scratch resistance and film removal properties, characterized by having a lubrication coating of ^-2 or less.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The surface lubricated stainless steel sheet of the present invention and a treatment liquid used for forming a lubricated film thereon will be described in detail below. In the following description,% is% by weight unless otherwise specified.

Base Metal The base metal of the present invention is a stainless steel plate. A stainless steel sheet preferable as a base metal is generally one that is rolled by a small-diameter Sendzimir rolling mill, subjected to annealing pickling or bright annealing, and temper-rolled with a bright skin pass in order to ensure excellent surface gloss.

According to the present invention, the surface roughness of the base metal is Ra ≦ 0.15
The present invention is applied to a case where a stainless steel plate having a smooth surface and a beautiful metallic luster having a thickness of μm is used as a base metal. If the surface roughness is higher than this, the metallic luster characteristic of the stainless steel sheet becomes dull, and the required level of scratch resistance at the time of plastic working becomes lower. Therefore, a conventional lubricating film can be used. Preferred surface properties are those having a surface roughness of Ra ≦ 0.08 μm.

According to the present invention, the surface of one or both surfaces (preferably both surfaces) of a stainless steel plate as a base metal is
A lubrication treatment in which a treatment solution containing an alkali-soluble resin component, a lubricating component, and a silane coupling agent is applied, the coating film is dried, and the film is easily removed with an alkali solution (eg, a commercially available alkali degreasing solution). Form a film. Next, these components will be described.

As a resin component (film-forming component) constituting a main component of the lubricating film, an aqueous treatment solution can be prepared, and the film can be easily removed by washing with an alkali solution. Water-soluble or water-dispersible, alkali-soluble resin is used. Examples of such resins include acrylics,
Examples thereof include water-soluble or water-dispersible resins such as epoxy-based, melamine-based, and phenol-based resins, and can be selected from those conventionally used in water-based paints. These alkali-soluble resins are generally polymers having an acid value in which an acidic group is introduced into a molecule by copolymerizing an acidic monomer or modifying it with an acidic compound. There is no restriction on the polymerization method.

The alkali-soluble resin has a glass transition temperature.
Use a temperature between 10 ° C and 85 ° C. If the glass transition temperature of the resin is less than 10 ° C, the anti-blocking property of the lubricated film is insufficient, and when the surface lubricated metal plate is stored with the liquid plastic working oil not applied on it, There is a possibility that they may stick to each other to make peeling difficult, and that the scratch resistance is also deteriorated. On the other hand, the glass transition temperature of the resin
If the temperature exceeds 85 ° C, the workability of the film deteriorates. The glass transition temperature is preferably from 15 ° C to 60 ° C.

The alkali-soluble resin preferably has an acid value of 20 or more, more preferably 30 or more. If the acid value is less than 20, the resulting lubricating film may be insufficiently removed by an alkaline solution.

As the alkali-soluble resin, one or more water-soluble or water-dispersible alkali-soluble resins may be used, or at least one water-soluble and water-dispersible alkali-soluble resin may be used. You may use together.

Silane Coupling Agent In the present invention, in addition to the resin and the lubricating component, a silane coupling agent is present in the lubrication coating to enhance the adhesion of the lubrication coating to the base metal. The silane coupling agent is a hydrolyzable alkoxy group and / or halogen capable of reacting with a polar group present on the surface of a stainless steel plate as a base metal, and an organic group having affinity or reactivity with a resin component, particularly It is well known that a functional group-containing organic group is a compound bonded to a silicon atom, and has an effect of increasing the adhesion between an inorganic material and an organic resin. By including a silane coupling agent in the lubricated coating, even when severe plastic processing such as drawing is performed, the coating is less likely to peel, and the occurrence of scratches due to the peeled coating can be prevented. The stickiness is dramatically improved.

The amount of the silane coupling agent is 5.0% or less based on the solid content of the resin. If the compounding amount exceeds 5.0%, the crosslinking of the resin film proceeds remarkably, and the film removing property after plastic working deteriorates. The lower limit is not particularly limited, but is preferably 0.1% or more. A more preferred amount is 0.5 to 3.0
%.

The type of the silane coupling agent used in the present invention is not particularly limited. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and N- (2-aminoethyl) -3.
-Aminopropylmethylmethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like, but others can also be used. Also, two or more silane coupling agents can be used in combination.

Metal Soap The lubricating film of the present invention contains a metal soap as a lubricating component. Examples of the metal soap include aluminum stearate, calcium stearate, zinc stearate, magnesium stearate and the like, but other than these can also be used. Also, two or more kinds can be used. Metal soaps are generally fine particles,
It can be easily dispersed in an aqueous treatment liquid.

The amount of the metal soap is based on the solid content of the resin.
0.5% or more and 10% or less. Preferably it is 1 to 5%. If the amount is less than 0.5%, the lubricity becomes insufficient, and
%, The effect of improving lubricity is not only saturated, but also the cohesive strengthening of the resin film is reduced and the scratch resistance is deteriorated.

Lubricated film The surface-lubricated stainless steel sheet of the present invention comprises a lubricated film formed from an aqueous treatment solution containing the above-mentioned alkali-soluble resin, a silane coupling agent and a metallic soap. Has on the surface of stainless steel plate. The lubricating film may be formed by applying the above-mentioned aqueous treating solution to the surface of the base metal in accordance with a conventional method, and optionally heating and drying the coating film.

The thickness of the lubricating film on the surface lubricated stainless steel sheet of the present invention is 0.5 μm or more and 10 μm or less. If the thickness is less than 0.5 μm, the scratch resistance is insufficient, and
If the thickness exceeds μm, the problem of film deposition on the mold occurs.
The preferred film thickness is 1.0 μm or more and 5.0 μm or less.

The surface unevenness of the lubricating film is set so that the average inclination angle (Δa) is 2.62 × 10 ⁻² or less. The average inclination angle (Δa) of the surface irregularities is a surface roughness parameter shown in ISO standard 4287, and is an index indicating how much the surface irregularities are inclined with respect to a reference plane.
A smaller value indicates a smoother surface. The average inclination angle (Δa) of the surface irregularities of the lubrication coating film is 2.
If it is larger than 62 × 10 ^-2 , the contact surface with the mold during plastic working becomes uneven, and the protrusions in contact with the mold remain as indentations on the surface of the base metal, impairing the aesthetic appearance after film removal. Will be. The preferable surface unevenness is 1.75 in average inclination angle (Δa).
× 10 ^-2 or less.

The average inclination angle (Δa) of the surface irregularities is determined by the surface roughness of the base stainless steel sheet, the resin type of the aqueous treatment liquid, the method of applying the treatment liquid, drying conditions, and the thickness of the coating (film thickness). Can be controlled by

The method for forming the lubricating film is not particularly limited, but a standard method will be described below.

Pretreatment The treatment liquid used for forming the lubrication treatment film is water-based since the main component resin is a water-soluble or water-dispersible resin.
For this reason, the stainless steel plate as the base metal needs to be sufficiently degreased by alkali degreasing or the like. If the degreasing is insufficient, defects such as repelling or uneven coating are generated on the formed film.

Treatment Solution The treatment solution is a water-soluble or water-dispersible alkali-soluble one.
The aqueous resin solution containing the seed or two or more kinds may be prepared by first adding a metal soap and sufficiently dispersing it, then adding a silane coupling agent, stirring, and, if necessary, diluting. it can. Dilution is carried out using ion-exchanged water. To improve wettability, defoaming and drying, organic solvents with good water compatibility (eg, alcohol, ketone, etc.)
May be added. The solid content concentration of the treatment liquid is adjusted according to the thickness of the lubricating film to be formed and the application method.

In addition to the above-mentioned components, small amounts of conventional additives such as dispersants and surfactants may be added to the treatment liquid. In order to further enhance the lubricity of the lubricating film, an appropriate amount of a solid lubricant such as wax can be added to the treatment liquid. Furthermore, a colorant (pigment or dye) is added to the treatment liquid to facilitate identification of the treated surface when only one side of the base stainless steel plate is lubricated, and to facilitate understanding of the state of film removal. It may be colored.

Application of Treatment Liquid The most preferred method of applying treatment liquid to stainless steel is by a roll coater. When a roll coater is used, it is easy to adjust the coating film thickness and beautiful coating is possible. In addition, a spray method, a brush coating method, and the like can be applied.

After applying the treatment liquid, it is dried to form a lubrication treatment film. The drying temperature may be such that the water evaporates, but it is preferable to carry out the drying under the condition that the maximum attained plate temperature is 40 to 100 ° C. As a drying method, a commonly used method such as hot air drying or infrared drying can be applied.

The surface lubricated stainless steel sheet of the present invention
The adhesion between the lubricating coating and the base metal is strong, and has excellent scratch resistance.
Also excellent in film removal and blocking resistance.

[0043]

The following examples illustrate specific examples of the present invention. Metal soap is first added to a resin solution in which various alkali-soluble resins having a glass transition temperature (Tg) and an acid value shown in Table 1 are dissolved or dispersed in water, and the mixture is sufficiently stirred and dispersed. Then, an aqueous treatment liquid having a solid content composition shown in Table 3 was prepared by adding and mixing a silane coupling agent. The total solid content of the treatment liquid was adjusted to 20% by adding ion-exchanged water.

This treatment liquid was degreased with alkali on the surface.
Various stainless steel plates shown in Table 2 (All are SUS430, plate thickness
1.2mm) on both sides with a bar coater.
It was dried in a hot air oven at 60 ° C. for 5 minutes to form a lubricating film on the surface of the stainless steel plate. The test plate of the surface-lubricated stainless steel sheet thus obtained was subjected to the following tests to investigate its performance, and the average inclination angle (Δa) of the surface unevenness of the lubricated film was measured by a contact three-dimensional roughness meter. The results are shown in Table 3.

Evaluation Test for Scratch Resistance Using a simple sliding test apparatus shown in FIG. 1, a test was performed by sliding the test piece while pressing a polished die against the test piece under the following conditions. The scratches of the part were visually observed, and the scratch resistance was evaluated according to the following criteria. ◎ or ○ indicates good.

Dice polishing paper: # 600 Dice polishing direction: Parallel polishing Pressing pressure: 0.66 Mpa (66 g / mm ² ) Test specimen collection direction: Rolling direction Test specimen shape: 1.2 mm thick × 30 mm width × 150 mm length Moving length: 50 mm Judgment criteria ◎: Completely scratch-free ○: Minor rubbing scratch, slight dent (no problem in appearance) △: Minor rubbing scratch, slight dent (problem in appearance) ×: clear rubbing Scratches, clear indentations.

Evaluation test for removal of membrane A commercially available alkaline degreasing solution (FC manufactured by Nippon Parkerizing Co., Ltd.)
-L-4480) at a temperature of 40 ° C. and a spray pressure of 1 kg / cm ² by spraying on one side of the test piece for 10 seconds to remove the lubricating film. The presence or absence of water repellency was visually determined, and the film removal property was determined based on the following criteria.で あ れ ば: good

：: No water repelling Δ: Part of the water repelling ×: Water repelling occurred all over.

Blocking Resistance Evaluation Test The blocking resistance is the resistance of the lubricated films to sticking (blocking) when the surface lubricated metal plates are stacked and stored. When this sticking occurs, workability decreases and plastic workability deteriorates.

The test was carried out by superimposing the films of two test pieces having a lubricated film only on one side at 40 ° C. and 200 ° C.
The adhesive state after pressing with a pressure of kg / cm ² for 3 hours and peeling was evaluated in the following four grades. ◎ or ○ indicates good.

◎: Peeled off by its own weight and no sticky marks ：: Peeled off by its own weight, but sticky marks were observed.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

As can be seen from the results shown in Table 3, the surface lubricated stainless steel sheet according to the present invention was excellent not only in scratch resistance but also in film removal property and blocking resistance.

[0056]

The surface lubricated stainless steel sheet of the present invention has excellent adhesion of the lubricated coating to the base metal,
Even when subjected to severe plastic processing such as drawing, the coating is hardly peeled off. Therefore, surface flaws do not occur due to contact with a mold during plastic processing, and the film is excellent in film removal and blocking resistance after molding.

Therefore, in order to prevent scratches during plastic working, it can be used in place of a conventional stainless steel plate for plastic working to which a vinyl sheet is pasted. This eliminates the need for laminating and peeling vinyl sheets,
The workability of plastic working of stainless steel sheets is remarkably improved, and the problem of vinyl sheet disposal is eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a simple type sliding test apparatus used in a scratch resistance evaluation test in Examples.

[Explanation of symbols]

1: material, 2: die, 3: holder, 4: load, 5:
Slide table

Claims (1)

[Claims] 1. A water-soluble or water-dispersible and alkali-soluble at least one glass transition temperature of not less than 10 ° C. and not more than 85 ° C. on a surface of a stainless steel plate having a surface roughness of Ra ≦ 0.15 μm.
Kind of resin and alkali-soluble resin solid content
The average inclination angle of the surface unevenness is 0.5 μm or more and 10 μm or less, formed from an aqueous treatment solution containing 5.0% by weight or less of a silane coupling agent and 0.5% by weight or more and 10% by weight or less of a metal soap. A surface-lubricated stainless steel sheet excellent in scratch resistance and film-removing property, characterized by having a lubricated film having Δa) of 2.62 × 10 ^-2 or less.