JP5261093B2 - Lubricating composition, lubricating composition-coated metal sheet, and method for producing lubricating composition-coated metal sheet - Google Patents

Description

  The present invention relates to a lubricating composition used during press forming of a metal plate, a lubricating composition-coated metal plate coated with the lubricating composition, and a method for producing the lubricating composition-coated metal plate.

  Metal plate press processing is used in a very wide range of fields, from industrial products such as automobiles, home appliances, and office equipment to manufacturing daily necessaries such as beverage cans, sinks, and bathtubs. Occupies a position. Usually, when press working is performed, lubrication and workability are improved by applying press oil (lubricating oil) in order to prevent scratches on the mold or metal plate surface due to poor lubrication. Yes. However, in recent years, in order to meet the needs of automobile weight reduction, for example, high-tension steel plates and aluminum alloy plates that are difficult to press are applied more than cold-rolled steel plates. There is an increasing need for improved performance.

  In addition, when press oil is applied, the working environment deteriorates due to the scattering of the press oil. Recently, the environmental load has increased due to evaporation of organic solvents such as chlorine-based materials used for cleaning press oil after molding. Such problems have been pointed out.

  Therefore, a solid coating layer having excellent lubricity is formed in advance on the surface of the metal plate as a method capable of preventing deterioration of the working environment such as press oil scattering and cleaning agent evaporation and an increase in environmental load while improving moldability. The method is known. This is a material manufacturer that is a metal plate supplier, and after forming a solid lubricant coating layer on the metal plate surface in advance (so-called pre-coating), it is supplied to the customer and press-molded without using lubricating oil when processed by the customer. Can be done.

  As such a pre-coating material, a non-delaminating type resin-coated metal plate designed to use the resin coating layer as it is as a coating film in the final product with emphasis on the merit of simplification of the painting process in the customer There is. However, in the case of such a resin-coated metal plate, the coating layer remains on the surface of the metal plate even after press molding, so the conductivity is poor, and the problem that chemical conversion treatment, electrodeposition coating, welding, etc. cannot be performed after press molding, However, there is a problem that it is technically difficult to combine the press formability (workability) and the required properties such as chemical resistance, corrosion resistance, and scratch resistance as the final coating film.

  Therefore, as the coating film in the final product is formed in a separate process, a film removal type coating layer with excellent lubricity is formed, and this coating is performed in the alkaline degreasing process, which is a pretreatment of the coating process after press molding. Resin-coated metal plates designed to be able to remove layers have been developed. In the case of this resin-coated metal plate, the removal of the coating layer is simple because it can use an alkali degreasing process that has been conventionally incorporated in a metal plate coating line.

  As such a film-removable resin-coated metal plate, for example, Patent Document 1 discloses a water-soluble copolymer having a methacrylic acid ester or the like as a monomer, and an alkali having a prescribed glass transition temperature of the methacrylic acid ester. A film removal type composition (paint) and a steel sheet having a coating film formed of the paint are disclosed. This technique is aimed at improving rust prevention and press formability of the steel sheet.

  Patent Document 2 describes a technique related to a metal lubricated with a lubricant having a partial ester such as a dihydroxy compound such as ethylene glycol monolaurate as an essential component. This lubricant film is said to have lubricating properties suitable for press molding operations and can be easily removed with an aqueous alkaline cleaner.

  Further, Patent Document 3 discloses an alkali-soluble type lubricated coated stainless steel sheet on which a film containing a polyolefin wax or the like is formed as a lubricant imparting agent, and Patent Document 4 has a similar film. An aluminum alloy plate is described. These films have alkali film-removing properties and certain moldability.

  Patent Document 5 discloses an aluminum alloy plate having a surface of a polyethylene oxide film having an average molecular weight of 50,000 to 5,000,000, that is, a relatively high molecular weight polyethylene glycol film. Furthermore, Patent Document 6 describes a lubricant containing a polyalkylene oxide such as polyethylene oxide and a higher fatty acid salt, and an aluminum or aluminum alloy plate coated with the lubricant. Patent Document 7 discloses a plastic processing coating agent composition containing polyoxyethylene ether having an HLB value of 12 or more and an oxyethylene unit number of 40 to 60, and the like.

  Here, as a method for forming the resin coating layer in the above-described prior art, a coating material in which the components of the coating layer are dissolved or dispersed in a solvent is prepared, and this is applied onto a metal plate, and then the solvent is evaporated by heating. A method (coating method) for forming a coating layer by removing the coating layer is applied.

  However, when forming a resin coating layer by a coating method, a large amount of heat energy is required for heating to remove the solvent, and organic solvents such as xylene, toluene, cyclohexanone, etc., which are frequently used as solvents. There is a problem in that the release of air into the atmosphere is unavoidable, and the cost and environmental load for that are large.

  Therefore, a method for forming a coating layer that is low in cost and has a low environmental burden, that is, requires a small amount of heat for forming the lubricant coating layer and does not release the organic solvent into the atmosphere has been attempted. As this method, only the constituent components of the coating layer are heated and melted, and this is applied to a metal plate by an electrostatic coating (or electrostatic coating oil) method, and the metal plate is naturally cooled. A method of solidifying the object to be coated and forming a film is conceivable.

In the electrostatic coating method, liquid oil, which is an object to be coated, is generally charged by feeding it to a nozzle to which a high voltage is applied, and this is finely divided / atomized and ejected from the nozzle. The metal plate is grounded to form a different electrode to promote the adhesion of atomized oil, and it has a feature that oil can be applied efficiently and evenly. A known method can be applied to an apparatus for performing this electrostatic coating method. For example, a coating liquid such as oil as described in Patent Document 8 is applied to various objects to be coated under the action of static electricity. An electrostatic liquid applicator for spraying toward the surface and applying evenly can be used.
JP 2000-38539 A Japanese translation of Japanese translation of PCT publication No. 8-502089 JP 2001-172776 A JP 2002-371332 A JP-A-8-323286 WO95 / 18202 pamphlet Japanese Patent No. 3092423 JP 2002-79144 A

  As described above, resin-coated metal plates aiming at combining lubricity and film removal properties have been known so far. However, the resin coating layer (resin layer) used in these conventional resin-coated metal plates has the following problems.

  For example, although the resin layer of Patent Document 1 is improved in press formability by this resin layer, the lubricity is not sufficiently satisfactory for application to an aluminum alloy plate or the like that is difficult to press form. As a result, the metal plate provided with this resin layer may not have sufficient press formability.

  Even in the technique of Patent Document 2, although the lubricity is improved by the lubricant layer, it cannot be said that it has sufficient lubricity yet, and the metal plate provided with this resin layer has a press formability and is a consumer. It could not be said that it could be satisfied with the request. Further, there is a problem that the film removal property is not sufficient when the temperature of the cleaning solution is low (for example, 40 ° C.).

  In addition, the resin layers disclosed in Patent Documents 3 and 4 also have improved lubricity when applied to materials that are difficult to process, although the press formability is improved by this resin layer. However, there was still a problem that the press formability was not sufficiently satisfactory.

  On the other hand, Patent Documents 5, 6, and 7 describe an aluminum plate or the like having a resin layer containing a polyethylene oxide skeleton, and its formability and film removal properties have been experimentally verified. However, in view of the advanced molding characteristics required for automobile outer plate materials and the like in recent years, further improvement in press formability is necessary.

  Moreover, when the conventional resin-coated metal plates are laminated and stored, particularly when the number of laminated layers is large, or in a high temperature environment such as a tropical region or summer, the resin layers may be bonded (blocking). When such blocking occurs, it becomes difficult to take out the metal plates one by one at the time of use, the workability is inferior, and the amount of resin adhered becomes non-uniform due to peeling of the resin layer, and stable moldability cannot be obtained. There was a problem.

  Furthermore, when performing resistance spot welding, a conventional resin-coated metal plate has a problem in that sufficient bonding strength cannot be obtained because a coating (coating layer) that is an insulator is interposed. Therefore, there are known methods for reducing the adhesion amount of the coating, introducing metal powder into the coating, etc., and ensuring the electrical conductivity and improving the weldability. It was not enough to solve the problem. In addition, as a problem of the lubricating composition itself, the stability of the lubricating composition may be impaired due to thermal decomposition or phase separation of the molten lubricating composition.

  Regarding the method of forming the resin coating layer, in order to form the lubricating coating layer at a low cost and with a low environmental load, the lubricating composition is heated and liquefied and then applied with an electrostatic coating method. After coating, it is preferable to form a film by naturally cooling the metal plate coated with the lubricating composition to solidify the lubricating composition. However, the conventional resin composition cannot be applied due to reasons such as high melt viscosity of the constituent components, poor handleability in the melted state, or low electrical resistance value that cannot be charged. .

The present invention has been made in view of the above-mentioned problems, and the object thereof is excellent in stability, and can improve the press formability (lubricity) of a metal plate and the film removal property by alkali treatment. It is another object of the present invention to provide a lubricating composition capable of improving blocking resistance, weldability, and the like, and a lubricating composition-coated metal sheet coated with the lubricating composition.
Also provided is a method for producing a lubricating composition-coated metal sheet for forming a lubricating composition coating layer having such characteristics on a metal sheet at low cost, high efficiency, and without giving a large environmental load. It is in.

  As a result of intensive studies, the present inventors have been able to improve the press formability (hereinafter also simply referred to as formability) of a metal plate without being thermally decomposed or phase separated in a molten state, and can be easily removed by alkali cleaning. Lubricating composition capable of forming a coating layer on a metal plate by a method that has a melting point of room temperature or higher and has a low environmental load, a lubricating composition-coated metal plate coated with the same, and lubrication The production method of the composition-coated metal sheet was found and the present invention was completed.

  That is, the lubricating composition according to claim 1 is a lubricating composition containing waxes containing paraffin wax and polyoxyethylene alkyl ethers, and has a melting peak temperature defined by JIS K7121 of 35. The polyoxyethylene alkyl ethers have an HLB (Hydrophile-Lipophile Balance) value of 10 to 14, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, and polyoxyethylene alkyl ethers. It is one or more selected from oxyethylene lanolin alcohol ether.

  According to such a lubricating composition, the inclusion of waxes containing paraffin wax as an essential component improves the formability of the lubricating composition-coated metal sheet coated with the lubricating composition, and has an electric resistance value. It can improve and can provide electrostatic applicability. Further, by containing at least one selected from predetermined polyoxyethylene alkyl ethers having an HLB value of 10 to 14, these are compatible with waxes in a molten state, so that stability is imparted. The film removal property (alkali film removal property) of the lubricating composition-coated metal plate by alkali treatment is imparted. Furthermore, since the melting peak temperature specified by JIS K7121 is 35 ° C. or higher, blocking where metal plates adhere to each other is difficult to occur. The “stability” in the present invention refers to a property that the molten lubricating composition is not thermally decomposed or separated even when left standing.

  The lubricating composition according to claim 2 is the lubricating composition according to claim 1, further comprising at least one selected from higher fatty acids having 10 to 20 carbon atoms and higher alcohols having 10 to 20 carbon atoms. It is characterized by containing.

  The lubricating composition according to claim 3 is the lubricating composition according to claim 1 or 2, further comprising resin fine particles having an average particle size of 10 μm or less, and the resin composition in the lubricating composition. The mass ratio of the fine particles is 30% by mass or less.

  According to such lubricating compositions, the formability of the lubricating composition-coated metal plate is further improved by using predetermined higher fatty acids and / or higher alcohols or resin fine particles in combination with the above components. .

  The lubricating composition according to claim 4 is the lubricating composition according to any one of claims 1 to 3, further comprising an organic peroxide, wherein the organic peroxidation in the lubricating composition is included. The mass ratio of the object is 10% by mass or less.

  The lubricating composition according to claim 5 is the lubricating composition according to claim 4, wherein the organic peroxide is a dialkyl peroxide.

  According to the lubricating composition as described above, when resistance spot welding is performed on the lubricating composition-coated metal sheet coated with these lubricating compositions, liquid oil is applied or coated with a solid lubricant. Bonding strength equivalent to that of a metal plate that has not been obtained can be obtained.

  The lubricating composition according to claim 6 is characterized in that the electrical resistance value at 90 ° C. of the lubricating composition according to any one of claims 1 to 5 is 30 MΩ or more.

  According to such a lubricating composition, the electrostatic composition is applied as a method for applying the lubricating composition to the surface of the metal plate by setting the lubricating composition as described above to have an electric resistance value of 30 MΩ or more. When is used, formation of the lubricating composition coating layer on the metal plate is facilitated.

A lubricating composition-coated metal sheet according to claim 7, wherein the lubricating composition according to any one of claims 1 to 6 is coated on both surfaces or one surface of the surface of the metal sheet. And the adhesion amount of the said lubricating composition is 0.2-2.0 g / m < ² > per single side | surface of the said metal plate, It is characterized by the above-mentioned.

  According to such a lubricating composition-coated metal plate, a predetermined amount of the above-described lubricating composition is coated on the surface of the metal plate, so that formability (lubricity), film removal, blocking resistance, weldability, and the like are improved. improves.

  A method for producing a lubricating composition-coated metal sheet according to claim 8 is the method for producing a lubricating composition-coated metal sheet according to claim 7, wherein the lubricating composition is maintained at a temperature equal to or higher than its melting point, After applying the electrocoating method to the surface of the metal plate, the metal plate coated with the lubricating composition is cooled to form a lubricating composition coating layer on the metal plate.

  According to the manufacturing method of such a lubricating composition-coated metal plate, an electrostatic coating method can be applied as a method of applying the lubricating composition to the surface of the metal plate, so there is no need to use an organic solvent, In addition, VOC (Volatile Organic Compounds) can be reduced. Furthermore, heating for removing the solvent becomes unnecessary.

  According to the lubricating composition of the present invention, the stability of the lubricating composition is improved, and even in difficult-to-work materials that are difficult to press, the lubricating composition can be coated without using lubricating oil. The press formability (lubricity) and the removability (film removal property) in the alkali film removal washing step can be improved, and the blocking resistance, weldability and the like can also be improved.

  According to the lubricating composition-coated metal plate according to the present invention, by having the coating layer (film) of the lubricating composition described above, the press formability (lubricity) and the alkali film removal washing step without using lubricating oil. The removability (film removal property) is improved, and the blocking resistance is also improved. Moreover, even if this coating layer is formed on the metal plate, the weldability and adhesiveness of the metal plate are not greatly reduced, and the molded metal plate and mold are hardened from this coating layer. It is hard to generate film waste.

  According to the method for producing a lubricating composition-coated metal sheet according to the present invention, the formation of the lubricating composition coating layer by applying an electrostatic coating method eliminates the need to use an organic solvent, thereby improving economic efficiency. Can be achieved. In addition, VOC can be reduced and the environmental load can be reduced. Furthermore, since heating for removing the solvent is not required, the amount of energy used during production can be greatly reduced, and economic efficiency and environmental burden can be reduced.

  Next, the lubricating composition, the lubricating composition-coated metal plate, and the method for producing the lubricating composition-coated metal plate according to the present invention will be described in detail.

First, the lubricating composition will be described.
≪Lubricating composition≫
The lubricating composition contains a wax containing paraffin wax and at least one selected from predetermined polyoxyethylene alkyl ethers, and has a melting peak temperature defined by JIS K7121 of 35. It is above ℃.
Each configuration will be described below.

<Wax>
The waxes contained in the lubricating composition of the present invention contain paraffin wax as an essential component, and other waxes that can be applied to the lubricating composition together with paraffin wax include microcrystalline wax and carnauba wax. , Montan wax, polyethylene wax, and derivatives thereof, and the like can be used alone or as a mixture.

  Waxes are useful for improving moldability and for improving electric resistance necessary for electrostatic coating. However, when the constituent ratio of the waxes in the lubricating composition is increased, the alkali film-removing property (hereinafter also referred to as film-removing property) is lowered, which is not preferable. A preferable content ratio of the waxes in the lubricating composition is 60% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less.

<Polyoxyethylene alkyl ethers>
Certain polyoxyethylene alkyl ethers are useful because they play a major role in imparting alkali film removal properties and are compatible with the waxes in a molten state.

  Examples of the polyoxyethylene alkyl ethers that can be applied to the lubricating composition include polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyoxyethylene lanolin alcohol ether, and derivatives thereof. These can be applied alone or in admixture.

  Here, these compounds (polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, and polyoxyethylene lanolin alcohol ether) are used as indices indicating the hydrophilicity / hydrophobicity of nonionic surfactants. It is required that the commonly used HLB (Hydrophile-Lipophile Balance) value is 10-14. An HLB value of less than 10 is not preferred because the alkali film removal property of the lubricating composition is deteriorated. On the other hand, if the HLB value exceeds 14, the compatibility with the wax in the heat-melted state tends to be lost, and in this case, the lubricating composition phase-separates in the heat-melted state. Since formation becomes difficult (stability is impaired), it is not preferable.

  The HLB value is a value mainly representing the degree of affinity of the nonionic surfactant to water and oil. The HLB value takes a value from 0 to 20, and the closer to 0, the higher the lipophilicity. , It is known that the closer to 20, the higher the hydrophilicity. This is described in known literatures such as “Introduction to New Surfactants” (Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.), and the formula for calculating the HLB value is “HLB value = hydrophilic group part” Molecular weight of surfactant / molecular weight of surfactant × 100/5 ”(griffin HLB value). Moreover, many nonionic surfactants marketed provide the HLB value by the manufacturer, and this can be utilized.

<The melting peak temperature specified in JIS K7121 is 35 ° C. or higher>
Since the lubricating composition maintains a solid state in a normal storage / use environment, the melting peak temperature defined by JIS K7121 needs to be 35 ° C. or higher.
When the melting peak temperature is less than 35 ° C., the solid state cannot be maintained and the moldability is lowered. In addition, for example, when a metal composition coated with a lubricant composition is laminated and stored or transported, depending on the season in summer or the tropics, geographical factors, or the storage environment, the coating layer may melt and the metal plates may This is not preferable because there is a concern about the occurrence of a so-called blocking problem of bonding. In addition, when using an electrostatic coating apparatus, a resin component may be used as a component of this electrostatic coating apparatus. When the heating temperature is 110 ° C. or higher, a high heat resistant resin must be used for the part. Therefore, the melting peak temperature is preferably less than 110 ° C.

The lubricating composition preferably further contains at least one selected from higher fatty acids having 10 to 20 carbon atoms and higher alcohols having 10 to 20 carbon atoms. By using these compounds in combination, moldability and the like can be further improved.
Examples of higher fatty acids and higher alcohols that can be applied to the lubricating composition include decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, eicosanoic acid, oleic acid, decyl alcohol, lauryl alcohol, myristyl alcohol, cecil alcohol, Stearyl alcohol, oleyl alcohol, and the like can be mentioned, and these can be applied alone or as a mixture.

Further, the lubricating composition preferably further contains resin fine particles. The moldability can be further improved by the combined use of resin fine particles.
Examples of resin fine particles that can be applied to the lubricating composition include fine particles made of amide wax, polyethylene, polypropylene, polytetrafluoroethylene, and the like, and these can be used alone or in combination.

  Here, the average particle diameter of the resin fine particles is preferably 10 μm or less. If the average particle diameter of the resin fine particles exceeds 10 μm, the resin fine particles are likely to fall off from the lubricating coating layer, and it is difficult to uniformly introduce the resin fine particles into the lubricating coating layer. The average particle diameter is not particularly limited as long as a known method is applied. In the present invention, the average particle diameter can be measured using a laser diffraction scattering method. An example of a specific measurement method is as follows. First, an appropriate amount of fine particles is taken into a 100 ml beaker, about 30 ml of solvent is added and stirred well, and then a sample is prepared by applying a homogenizer for about 1 minute. Next, the average particle diameter of this sample is measured using LS13 320 type (manufactured by Beckman Coulter). And among this measurement result, let D50 value be an average particle diameter. In Examples described later, the average particle size was measured by the measurement method.

  Moreover, it is preferable that the addition ratio of the resin fine particles is such that the mass ratio of the resin fine particles in the lubricating composition is 30% by mass or less. If the amount of resin fine particles added exceeds 30% by mass, the melt viscosity when the lubricating composition is heated increases remarkably, and it becomes difficult to form a lubricating coating layer by electrostatic coating. Even if it increases, since improvement of a moldability cannot be expected, it is not preferable.

  The lubricating composition preferably further contains an organic peroxide. In the case where resistance spot welding is performed on a lubricating composition-coated metal sheet coated with this lubricating composition by adding an organic peroxide to the lubricating composition, liquid oil is applied or coated with a solid lubricant. It is possible to obtain a bonding strength equivalent to that of a metal plate that is not polished.

  As the organic peroxide that can be applied to the lubricating composition, application of dialkyl peroxides is preferable, and more specifically, di-t-butyl peroxide, t-butyl-α-cumyl peroxide, di-α- Cumyl peroxide, 1,3-di (2-t-butylperoxyisopropyl) benzene, 1,4-di (2-t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-bis ( t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) -3-hexyne, diisopropylbenzene hydroperoxide and the like can be used alone or in combination. .

In the case of resistance spot welding of the lubricating composition-coated metal sheet, the lubricating composition is thermally decomposed and removed by the heat generated at that time. The lubricating composition of the present invention has a large molecular weight as compared with liquid oil generally composed of mineral oil or the like, and may require a little time for thermal decomposition and removal. The organic peroxide is decomposed by heat during resistance spot welding to generate radicals, which promote thermal decomposition of the lubricating composition by a chain reaction. For this reason, the thermal decomposition and removal of the lubricating composition proceeds rapidly and the obstruction (coating layer) during welding disappears, so that the metal plate not coated with liquid oil or coated with a solid lubricant Equivalent joint strength can be obtained.
Furthermore, when dialkyl peroxides are applied as the organic peroxide, the dialkyl peroxides have a high thermal decomposition starting temperature and high stability, so that when a coating layer is formed on a metal plate by an electrostatic coating method, Since the stability at the time of storage of the lubricating composition-coated metal plate is good, there is an advantage that the stability is high.

  The mass ratio of the organic peroxide in the lubricating composition is preferably 10% by mass or less. Even if the content of the organic peroxide is increased further, no further improvement in resistance spot weldability can be expected, and conversely, problems arise in formability, thermal decomposition stability, etc., which is not preferable.

Further, the lubricating composition preferably has an electric resistance value of 30 MΩ or more when melted at 90 ° C. When the electrical resistance value is less than 30 MΩ, it is not preferable because formation of the lubricating composition coating layer on the metal plate by the electrostatic coating method described later tends to be difficult. The preferable upper limit value of the electric resistance value depends on the material constituting the electrostatic coating apparatus. In other words, when the specific resistivity of the high voltage application portion of the electrostatic coating device (for example, 1 × 10 ¹⁴ Ωcm when it is made of a resin material such as polyacetal) is exceeded, the device itself can break down and be coated. Since it disappears, it is not preferable.
In addition, an electrical resistance value can be 30 M (ohm) or more because a lubricating composition contains wax containing paraffin wax.

Next, the lubricating composition-coated metal plate will be described.
≪Lubricating composition coated metal sheet≫
The lubricating composition-coated metal plate is obtained by coating the above-described lubricating composition on both surfaces or one surface of the metal plate.
This lubricating composition-coated metal sheet is not only characterized by exhibiting excellent press formability, but the lubricating composition coating layer formed on this lubricating composition-coated metal sheet can be widely used in automobile manufacturing processes, etc. It has the feature that it can be easily removed by the alkali cleaning method.

  The type of the metal plate to which the lubricating composition can be applied is not particularly limited, and examples include an aluminum plate, an aluminum alloy plate, a steel plate, a copper plate, and a titanium plate, and particularly preferably an aluminum alloy plate.

In the lubricating composition-coated metal plate, the adhesion amount of the lubricating composition is 0.2 to 2.0 g / m ² per one side of the metal plate. More preferably, it is 0.5 to 1.2 g / m ² .
If the adhesion amount is less than 0.2 g / m ^2, it is not preferable because improvement in moldability cannot be confirmed. On the other hand, if it exceeds 2.0 g / m ² , the cost is increased and the film removal property, weldability and adhesiveness are deteriorated, and even if the thickness is increased more than this, it is not preferable because improvement in moldability cannot be expected. In the present invention, “weldability” refers to the welding strength when resistance spot welding is performed, and “adhesiveness” refers to the tensile shear strength when bonded with an adhesive.

Next, a method for producing the above-described lubricating composition-coated metal plate will be described.
<< Manufacturing Method of Lubricating Composition Coated Metal Sheet >>
The manufacturing method of the lubricating composition-coated metal plate is to apply the lubricating composition after holding the lubricating composition at a temperature equal to or higher than the melting point and applying the electrostatic coating method to the surface of the metal plate. By cooling the metal plate, the lubricating composition coating layer is formed on the metal plate.

  Conventionally, the electrostatic coating method has a feature that oil can be applied to a metal plate with high efficiency, evenness, and high speed. In the formation of the lubricating coating layer of the present invention, the lubricating composition is liquefied by maintaining the temperature above its melting point, and the liquefied lubricating composition is applied to the surface of the metal plate by applying an electrostatic coating method. The lubricating composition coating layer is formed by cooling and solidifying the temperature of the metal plate below the melting point of the lubricating composition.

In order to achieve this, the lubricating composition has the characteristics that the melting peak temperature defined by JIS K7121 is 35 ° C. or higher, and the electrical resistance value at 90 ° C. is 30 MΩ or higher. Further, even when left in a molten state at 90 ° C. for 8 hours, separation, sedimentation, precipitation and the like do not occur, and extremely stable characteristics can be expressed.
By forming the lubricating composition coating layer by applying the electrostatic coating method, it is possible to eliminate the use of organic solvents such as xylene and toluene, which were essential in the coating method. It can be reduced and can contribute to the reduction of the environmental load that has become a social problem in recent years.

  In addition, since the applied lubricating composition can form a solid coating layer only by cooling, heating for removing the solvent, which is essential in the coating method, is not necessary. For this reason, the amount of energy used during production can be greatly reduced, and cost reduction and environmental load reduction can be achieved.

  Of course, in the production of the lubricating composition-coated metal sheet of the present invention, a conventional coating method can be applied. For example, the lubricating composition of the present invention is dissolved in an organic solvent such as xylene or toluene. -Disperse and prepare paint, form a coating film on the surface of the metal plate using a bar coater, roll coater, spray, etc., and then form a lubricating composition coating layer by heating to remove the solvent it can. Here, from the viewpoint of cost reduction and environmental load reduction, it is preferable to use an electrostatic coating method. However, the properties of the formed lubricating composition coating layer are different between the conventional coating method and the electrostatic coating method. There is no.

  As described above, the present invention mainly applies lubricating oil to galvannealed steel sheets, hot-rolled steel sheets, cold-rolled steel sheets, plated steel sheets, stainless steel sheets, aluminum plates, aluminum alloy plates, titanium plates, copper plates and the like. It has excellent press formability (lubricity) without use, is excellent in removability (film removal property) in the alkaline film removal cleaning step, and is also a metal plate when the lubricating composition-coated metal plates are laminated. Lubricating composition-coated metal sheet for producing a lubricating composition-coated metal sheet that does not adhere to each other (blocking resistance), and the lubricating composition-coated metal sheet, and the lubricating composition-coated metal sheet manufactured by an electrostatic coating method The present invention relates to a method for producing a lubricating composition-coated metal sheet.

  In addition, the lubricating composition is excellent in stability, which is a property that the molten lubricating composition is not thermally decomposed or separated even when it is left standing, and the lubricating composition-coated metal plate is composed of the coating layer (film). Even if it is formed on a metal plate, the weldability and adhesion of the metal plate are not significantly reduced, and hard coating scraps derived from the coating layer are unlikely to be generated on the molded metal plate or mold. It also has the feature.

  Next, with respect to the lubricating composition, the lubricating composition-coated metal sheet, and the method for producing the lubricating composition-coated metal sheet according to the present invention, an example that satisfies the requirements of the present invention and a comparative example that does not satisfy the requirements of the present invention Will be described in detail.

(First embodiment)
By forming a coating layer made of the lubricating composition shown in Table 1 on both sides or one side of a metal plate (plate thickness: 1 mm), a plurality of lubricating composition-coated metal plates were produced and their characteristics were evaluated.

<Method for preparing lubricating composition-coated metal plate, part 1>
Lubricating compositions were prepared according to the amounts shown in Table 1. In blending, an oil bath was applied and heated to about 90 ° C. to melt and stirred until homogeneous.
Next, this lubricating composition was heated to about 90 ° C. and melted, applied with an electrostatic oiling device (manufactured by Lubtec) and applied to the surface of a metal plate (plate thickness 1 mm) shown in Table 1, The lubricating coating layer was formed by allowing to cool as it was.

<Method for preparing lubricating composition-coated metal plate, part 2>
The lubricating composition was adjusted according to the blending amount shown in Table 1, dissolved in toluene, and a lubricating composition-containing coating was prepared (coating concentration: 5% by mass).
Next, this lubricating composition-containing coating was applied to a metal plate (plate thickness: 1 mm) shown in Table 1 with a bar coater, and then the solvent was evaporated and removed by heating to about 110 ° C. to form a lubricating coating layer.

  The melting peak temperature, electrical resistance value, and stability of the lubricating composition applied to the lubricating composition-coated metal sheet are measured or evaluated in advance, and the lubricating composition-coated metal sheet thus prepared is used for the lubricating composition. The amount of adhesion was measured. And evaluation of weldability was performed in addition to formability, film removal property, and blocking resistance. In addition, these evaluations were performed on the metal plate produced in “Production Method of Lubricating Composition-Coated Metal Plate, Part 2”. Further, in “Production Method of Lubricating Composition-Coated Metal Plate, Part 1”, it was confirmed that the lubricating composition of the present invention can be electrostatically applied.

[Measurement of melting peak temperature]
Using a differential scanning calorimeter (DSC7, manufactured by Perkin Elmer), the melting temperature of the lubricating composition defined in JIS K7121 was measured under the conditions of a sample mass of about 10 mg and a heating rate of 10 ° C./min. A DSC curve having a melting peak temperature of 35 ° C. or higher was rated as “◯”, and a DSC curve having a melting peak temperature of less than 35 ° C. as “×”.

[Measurement of electrical resistance]
The lubricating composition was heated to 90 ° C. and melted, and the electrical resistance value was measured using an electrostatic tester (EM-IV type manufactured by Asahi Sunac Corporation).

[Evaluation of stability]
The lubricating composition was put in a glass container, heated to 90 ° C. and melted, allowed to stand for 8 hours in the heated state, and then visually observed for thermal decomposition stability and occurrence of phase separation in the lubricating composition. A sample in which thermal decomposition or phase separation did not occur was rated as “good”, a sample in which there was a sign of thermal decomposition or phase separation was evaluated as “Δ”, and a sample in which thermal decomposition or phase separation was clearly generated was evaluated as “bad”.

[Measurement of adhesion amount of metal plate coated with lubricating composition]
An infrared oil amount meter (SC4000 type manufactured by Thermo Electron) was used to measure the coating amount (attachment amount) of the lubricating composition on the surface of the metal plate.

[Evaluation of formability]
The outer periphery of a metal plate test piece (width 180 mm × length 110 mm × thickness 1 mm) coated on both surfaces with a lubricating composition was restrained with a lock bead with a crease pressing force (P) of 200 kN. Using a hemispherical punch having a diameter (Dp) of φ50.8 mm, this test piece was stretched and molded by an 80-ton hydraulic press (Amino Co., Ltd., model 1M080L) at a press speed of 4 mm / s until the test piece was broken. The molding height was measured. The measurement was performed on each metal plate in three cases, and the average value was defined as LDH (mm). Here, as the formability in the case of using an aluminum plate, those having an LDH value of 35.0 mm or more are good, and those having a formability of less than 35.0 mm are bad.

[Evaluation of film removal]
One test piece (100 mm wide x 100 mm long x 1 mm thick) coated with a lubricating composition on one side of a metal plate was prepared, and an alkaline cleaning solution having a pH of 11 to 12 maintained at 40 ° C. (Surf manufactured by Nippon Paint Co., Ltd.) It was immersed in cleaner EC90 (registered trademark)) for 2 minutes and then washed with water for 1 minute.

  The test piece subjected to the film removal treatment by the above-described method was immersed in a surface adjustment liquid (Surf Fine 5N (registered trademark) manufactured by Nippon Paint Co., Ltd.) maintained at 20 ° C. for 30 seconds, and then maintained at 40 ° C. It was immersed in a treatment solution (Surfdyne SD6000 (registered trademark) manufactured by Nippon Paint Co., Ltd.) for 2 minutes, further washed with water for 1 minute, and dried.

  After film removal, the surface of the test piece subjected to chemical conversion treatment was observed with an SEM, and the formation state of zinc phosphate crystals was observed to evaluate the film removal property of the lubricating coating layer. A film in which homogeneous zinc phosphate crystals could be observed, or a film having a non-adhered portion in part was evaluated as good film removal property, and a film in which no or almost no film was adhered was evaluated as poor.

[Evaluation of blocking resistance]
Using two metal plate test pieces (100 mm wide x 100 mm long x 1 mm thick) coated with a lubricating composition on one side, the respective resin-coated surfaces and metal surfaces were overlapped and a load of 10 MPa was applied, at 50 ° C. Hold for 2 hours. Next, after releasing the pressure and gradually cooling to room temperature, the presence or absence of adhesion between the plates and the transition state of the resin layer from the lubricating composition coating layer to the metal surface were observed with the naked eye. Those having no migration of the lubricating composition layer, or those having migration but no adhesion between the plates were good in blocking resistance, and those having adhesion between the plates and not being peeled off by their own weight were judged as poor x.

[Evaluation of weldability (resistance spot weldability)]
The lubricating composition shown in Table 1 on both sides of a 6K21 aluminum material (width 30 mm × length 100 mm × thickness 1 mm), so that the adhesion amount per side is 0.8 g / m ² and the first embodiment. The coating was carried out in the same manner. The two resin-coated metal plates are overlapped with a lap width of 30 mm, and the stacked portion is subjected to continuous 30-point resistance spot welding at a pressure of 2.9 kN and energization: 29 kA × 4 cycles, 1, 5, 9, 16, The average welding strength was calculated by measuring the welding strength at the 24th and 30th points. This average weld strength is 2.9 kN or more and weldability is particularly excellent ◎ 2.7 kN or more and less than 2.9 kN is excellent ○, 2.0 kN or more and less than 2.7 kN is good △, 2.0 kN Less than or a thing which cannot be welded was made into bad x.
These results are shown in Tables 1-3. In Tables 1 and 2, those that do not satisfy the scope of the present invention are underlined.

  As shown in Table 3, the example No. Since Nos. 1 to 29 satisfy the configuration of the present invention, the stability, formability, film removal property, blocking resistance, and weldability were all particularly excellent, excellent, or good.

  In addition, No. 18 is within the scope of the present invention, but the amount of resin fine particles introduced into the lubricating composition exceeds the upper limit of the preferred range of the present invention, so the melt viscosity of the lubricating composition is high and during electrostatic application. The workability of a little worsened. No. No. 19 is within the scope of the present invention, but the average particle size of the resin fine particles in the lubricating composition exceeds the upper limit of the preferred range of the present invention. It was easy to occur. No. 25 is within the scope of the present invention, but since the organic peroxide content in the lubricating composition exceeds the upper limit of the preferred range of the present invention, there is no sign of thermal decomposition in the lubricating composition in terms of stability. there were.

  On the other hand, No. which is a comparative example. Since 30-38 did not satisfy | fill the structure of this invention, it had the following malfunctions.

  No. No. 30, because the HLB value of polyoxyethylene stearyl ether was less than the lower limit of the present invention, the film removal property by alkali cleaning of the lubricating composition-coated metal plate was insufficient. No. In No. 31, since the HLB value of polyoxyethylene cetyl ether exceeded the upper limit of the present invention, phase separation occurred in the lubricating composition during melting and the stability was poor.

  No. No. 32 had an HLB value of polyoxyethylene cetyl ether less than the lower limit of the present invention, so that the film-removing property of the lubricating composition-coated metal plate by alkali cleaning was insufficient. No. Since No. 33 uses polyoxyethylene lauryl ether, since the melting peak temperature of the lubricating composition is less than the lower limit of the present invention, the lubricating coating layer cannot maintain a solid shape, and formability and blocking resistance Was inferior. Moreover, since the HLB value of polyoxyethylene lauryl ether was high, it was inferior to stability.

  No. In No. 34, the lubricating composition was composed only of paraffin wax having no water solubility, and the film removal property by alkali cleaning was insufficient. No. No. 35 was inferior in moldability because it did not contain waxes in the lubricating composition. Moreover, the electrical resistance value at the time of melting was less than the lower limit of the present invention, and electrostatic coating was impossible. No. No. 36 was obtained by applying liquid oil as a lubricant and was inferior in moldability as compared with the lubricating composition (solid lubricant) of the present invention.

No. 37, the lubricating composition satisfies the constitution of the present invention. However, as the lubricating composition-coated metal plate, the amount of adhesion of the lubricating composition to the metal plate is the same as that of the lubricating composition-coated metal plate of the present invention. Since it was less than the lower limit value of the configuration, the moldability was poor. No. No. 38 satisfies the configuration of the present invention as a lubricating composition, but as the lubricating composition-coated metal plate, the adhesion amount of the lubricating composition is the upper limit of the configuration of the lubricating composition-coated metal plate of the present invention. Therefore, it was inferior in film removal and weldability by alkali cleaning. In addition, about weldability, it is No .. In Nos. 37 and 38, in order to investigate weldability when the adhesion amount of the lubricating composition does not satisfy the configuration of the lubricating composition-coated metal plate of the present invention, the adhesion amount is 0.1 g / m ² , and the adhesion amount is 2.2 g / The weldability at m ² was examined in the same manner as in the evaluation method and evaluation criteria.

(Second embodiment)
The lubricating oil composition shown in Table 4 on both surfaces of an electrogalvanized steel sheet (thickness 1 mm, plating adhesion amount: 30 g / m ² ), the first embodiment so that the adhesion amount per one surface becomes 0.8 g / m ^2. The characteristics of the lubricating composition-coated metal sheet coated in the same manner as in Example 1 were evaluated in the same manner as in the first example.
In addition, the melting peak temperature of the lubricating composition, the electrical resistance, the method for measuring the adhesion amount of the lubricating composition on the coated metal plate of the lubricating composition, and the evaluation of stability, formability, film removal, blocking resistance and weldability The method and evaluation criteria are the same as in the first embodiment.
These results are shown in Tables 4 and 5. In Table 4, those not satisfying the scope of the present invention are indicated by underlining the numerical values. As for formability, the formability in the case of using a steel plate is herein that the LDH value is 40.0 mm or more, the formability is good, and the formability is less than 40.0 mm.

  As shown in Table 5, No. satisfying the configuration of the present invention. No. 39 was particularly excellent, excellent, or good in all of stability, moldability, film removal property, blocking resistance, and weldability. No. No. 40 was obtained by applying liquid oil as a lubricant, and was inferior in moldability as compared with the lubricating composition (solid lubricant) of the present invention.

  As described above, the lubricating composition, the lubricating composition-coated metal plate, and the method for producing the lubricating composition-coated metal plate according to the present invention have been described in detail with reference to the best embodiments and examples. Is not limited to the contents described above. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

Claims (8)

A lubricating composition comprising waxes containing paraffin wax and polyoxyethylene alkyl ethers,
The melting peak temperature specified in JIS K7121 is 35 ° C. or higher,
The polyoxyethylene alkyl ethers are polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, and polyoxyethylene lanolin alcohol ether having an HLB (Hydrophile-Lipophile Balance) value of 10 to 14. A lubricating composition characterized in that it is at least one selected from the group consisting of:   The lubricating composition according to claim 1, further comprising at least one selected from higher fatty acids having 10 to 20 carbon atoms and higher alcohols having 10 to 20 carbon atoms. object. The lubricating composition according to claim 1 or 2, further comprising resin fine particles having an average particle size of 10 μm or less,
A lubricating composition, wherein a mass ratio of the resin fine particles in the lubricating composition is 30% by mass or less. The lubricating composition according to any one of claims 1 to 3, further comprising an organic peroxide,
A lubricating composition, wherein a mass ratio of the organic peroxide in the lubricating composition is 10% by mass or less.   The lubricating composition according to claim 4, wherein the organic peroxide is a dialkyl peroxide.   The lubricating composition according to any one of claims 1 to 5, wherein the electrical resistance value at 90 ° C of the lubricating composition is 30 MΩ or more. A lubricating composition-coated metal sheet obtained by coating the lubricating composition according to any one of claims 1 to 6 on both surfaces or one surface of a metal sheet,
The lubricating composition-coated metal sheet, wherein the adhesion amount of the lubricating composition is 0.2 to 2.0 g / m ² per side of the metal sheet. A method for producing a lubricating composition-coated metal sheet according to claim 7,
Holding the lubricating composition at a temperature equal to or higher than its melting point, applying the electrostatic coating method to the surface of the metal plate, and then cooling the metal plate coated with the lubricating composition, the metal plate A method for producing a lubricating composition-coated metal sheet, comprising forming a lubricating composition coating layer on the substrate.