JPH08267002A - Lubricating resin-treated steel sheet excellent in continuous prism formability and continuous spot weldability - Google Patents

Abstract

PURPOSE: To obtain a lubricating resin-treated metallic sheet excellent in press formability in the lubricating resin-treated steel sheet with a chromate coating film provided on both sides of a zinc-plated steel sheet, etc., and a resin composition layer furnished thereon by preparing the resin composition layer from 2 kinds of resins each having a specified glass transition temp. CONSTITUTION: A chromate coating film is provided on both sides of a zinc or zinc-base alloy-plated steel sheet. The composition layer contains 1-4 pts.wt. of curing agent, 1-40 pts.wt. of lubricant and 5-80 pts.wt. of org. silicon compd., based on 100 pts.wt. of the resin, and formed from 2 kinds of resins having -30 to 90 deg.C glass transition temp. Namely, a resin having -30 to 30 deg.C glass transition temp. and the resin having 30 to 90 deg.C glass transition temp. are incorporated by, >=10wt.%, based on the total resin. The lubricant has 80 to 130 deg.C m.p., and the amt. to be deposited on one side is controlled to 0.1 to 1.0g/cm<2> on a dry basis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated metal plate used for automobiles, home electric appliances, building materials, etc., which is excellent in press workability, continuous welding point property, and conductivity and is treated with a lubricating resin. Regarding

[0002]

2. Description of the Related Art Steel sheets used for automobiles, home electric appliances, building materials, etc., especially plated steel sheets such as zinc or zinc-based plated steel sheets, are used unpainted or painted.
Before being actually used by a consumer (user), various processes are performed, and in the meantime, it is left unpainted for a considerably long time. Therefore, there are problems that rust is generated during that period, various substances are adsorbed and adhered to the surface of the plated steel sheet to cause a poor appearance, and the adhesion of the paint is deteriorated when applying the coating.

In order to prevent this, a chromate treatment is applied as a primary rust preventive treatment until the plated steel sheet is used by a consumer. However, the corrosion resistance obtained by the ordinary chromate treatment is generally about 24 to 48 hours in a salt spray test, and even if it is a special chromate treatment, that is, a coating type chromate treatment to which silica sol is added, a salt spray test is performed. Therefore, the durability can only be obtained for about 100 to 200 hours. Therefore, when this plated steel sheet is used for a product exposed to a severe corrosive environment for a long period of time, its corrosion resistance is insufficient.

In consideration of the case where the product is used in a severe corrosive environment, a phosphate treatment is applied instead of the chromate treatment, and then a coating of about 20 μm is applied to improve the corrosion resistance of the plated steel sheet. There are known ways to improve. However, when such a thick coating is applied, when the steel sheet is subjected to press working or the like, peeling or cracking of the coating film occurs, which causes local reduction in corrosion resistance at that portion. I will end up. In addition, the conductivity of such a coated plate is significantly reduced, and the performance related to conductivity such as spot welding and ground is reduced, or it becomes impossible to use it for applications that require them. It is necessary to remove the coating film from parts and the like in advance. Moreover, the thicker the coating film, the more paint is consumed, resulting in an increase in cost. Therefore, it is desired to develop a surface-treated steel sheet which itself has excellent corrosion resistance without using a paint.

On the other hand, such a plated steel sheet is often press-formed in the manufacturing process by the customer. Here, when press-forming a plated steel sheet, a lubricating oil is usually applied to the surface of the steel sheet in order to improve the formability, so a degreasing step after forming becomes essential. Therefore, it is desired to develop a surface-treated steel sheet that can be press-formed without using a lubricating oil or the like.

Further, when a consumer uses a surface-treated steel sheet to manufacture a product through various processes, fingerprints or other stains are attached to the surface of the steel sheet due to handling by an operator, etc. The product value may be significantly reduced. Therefore, it is desired to develop a surface-treated steel sheet which is less likely to be stained with fingerprints during handling.

As a surface-treated steel sheet satisfying such requirements as excellent corrosion resistance and stain resistance, and press forming possible even without applying a lubricating oil, a lubricating resin-treated steel sheet having an organic resin layer formed on the surface thereof. Have been developed. Lubricating resin-treated steel sheets that meet the above requirements are used in automobiles, home appliances, building materials, etc. by taking advantage of their characteristics. However, when they are used for household electronic and electrical products, they undergo square tube drawing. Since it is often used, more excellent press formability is required, and when it is used for steel sheets for automobiles and some home appliances, excellent spot weldability and electrodeposition coatability are required. Therefore, in addition to the above requirements for corrosion resistance and the like, the lubricating resin-treated steel sheet is required to have more excellent press formability without application of lubricating oil and electrical conductivity capable of favorably performing spot welding and electrodeposition coating.

As such a lubricating resin-treated steel sheet, Japanese Patent Publication No. 62-24505 has a chromate coating on a zinc-plated steel sheet, on which a composite aluminum phosphate and a chromium-based rust preventive pigment are added. Disclosed is a steel sheet having a urethane-modified epoxy resin layer containing 1 to 10 g / m ² containing a polyolefin wax, molybdenum disulfide and silicone as a lubricant and having excellent corrosion resistance and lubricity.

Further, in JP-A-63-83172, lubricants (polyethylene wax, fatty acid amino compounds, metal soaps, metal sulfides, fluorinated graphite, boron nitride, grease, alkali metals, etc. are contained in a resin. Sulfate, etc.) and conductive substances (carbon black, graphite, metal powder, semiconductor oxides, iron phosphide, etc.) are included to reduce the electrical resistance of the resin coating and prevent corrosion. Lubricating film forming resin compositions are disclosed.

Further, in JP-A-1-301332, there is a chromate coating on both sides of a zinc-based plated steel sheet, on which a resin having a hydroxyl group and / or a carboxyl group, an organosilicon compound, and A glass transition temperature (T
Disclosed is a lubricating resin-treated steel sheet having a resin composition layer having a g) of 70 ° C. or higher in a dry weight of 0.3 to 3.0 g / m ² per side.

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The steel sheet disclosed in Japanese Patent No. 505 exhibits excellent corrosion resistance due to the effects of the composite aluminum phosphate, the chromium-based anticorrosive content and the urethane-modified epoxy resin, and is also excellent due to the effects of the polyolefin wax, molybdenum disulfide and silicone. Expresses press formability. However, since this steel sheet has 1 to 10 g / m ^{2 of} urethane-modified epoxy resin layer, the electric resistance of this coating is high, so that the electrical conductivity is low and it is impossible to obtain good groundability and spot weldability.

Further, the rust preventive lubricating film forming resin composition disclosed in JP-A-63-83172 uses an inorganic substance as a conductive pigment, and therefore has a large pigment particle size.
Generally, the resin film thickness must be increased, and as a result, the powdering resistance during press working is poor, and the groundability and spot weldability are not improved as expected.

Further, the lubricating resin-treated steel sheet disclosed in Japanese Patent Application Laid-Open No. 1-301332 uses a blend of a low melting point wax and a high melting point wax for continuous press forming with one die. Also in the case of performing, good press moldability can be exhibited from the initial stage of molding to the temperature rising of the mold. However, since the Tg of the resin composition layer is as high as 70 ° C. or higher, continuous spotting property in spot welding is low.

Moreover, since the resin composition layer of this steel sheet is designed for the purpose of good press formability in the cylindrical cup drawing, the pressure is concentrated on a part of the corner, and high pressure sliding and low pressure during press forming. Good press formability cannot be obtained by square tube draw forming in which sliding and sliding are mixed. That is, in the cylindrical cup throttle, since the flange portion is circular, the steel plate slides evenly into the mold. Therefore, the resin composition layer is uniformly placed in a high-pressure state, and therefore, the object can be achieved with a resin composition layer having excellent lubricity at high pressure, high speed, and high temperature. On the other hand, in the square tube drawing, as described above, high-pressure sliding and low-pressure sliding are mixed during the forming. Therefore, good press formability in square tube draw forming cannot be realized unless a resin composition in which there is no difference in slip between high pressure and low pressure and pressure dependency of the lubricity of the steel sheet is not realized.

An object of the present invention is to solve the above-mentioned problems of the prior art. Not only in the cylindrical cup drawing, but also in the rectangular tube drawing, the molding is continuously performed at the initial stage of the molding, and the molding is continuously performed. Lubrication that provides good press formability (continuous rectangular formability) even when the mold is heated, has sufficient conductivity, and has excellent earthing properties and continuous welding point properties in spot welding. To provide a resin-treated steel sheet.

[0016]

As shown in the above-mentioned prior art, after the steel sheet surface is subjected to chromate treatment, a lubricous resin film is formed, so that the corrosion resistance and lubricity of the zinc-based plated steel sheet can be improved. Can be improved. The present inventors, while taking advantage of the advantages of such conventional technology, as a result of earnest studies to realize a surface-treated steel sheet having excellent continuous square tube formability even in high-speed press forming, and also having good continuous welding point properties, The uppermost organic resin layer is a combination of two or more resins having a hydroxyl group in the molecule of Tg of -30 ° C to 90 ° C, and a curing agent for the resin and a melting point of 80 ° C to 13 ° C.
A resin composition layer containing a lubricant at 0 ° C. and an organosilicon compound is formed, and the adhesion amount of the resin composition layer is set to 0.1 to 1.0 g / m ² in terms of dry weight. It has been found that the pressure dependence of the slippage of the steel plate during press forming can be reduced to realize excellent continuous rectangular tube formability, and further, sufficient conductivity can be ensured and excellent continuous welding spot property can also be realized. It came to be done.

[0017] Namely, the present invention is, on both surfaces of zinc or zinc-plated steel sheet, has a 10mg / m ² ~200mg / m ² of chromate film adhesion amount per one side reckoned as metal chromium resin thereon A lubricating resin-treated steel sheet having a material layer, wherein the resin composition layer is 5 to 40 parts by weight of a curing agent, 1 to 40 parts by weight of a lubricant, and 5 to 80 parts of an organosilicon compound with respect to 100 parts by weight of a resin. The resin contains 2 parts by weight or more of a resin having a glass transition temperature of −30 ° C. to 90 ° C. and having a plurality of hydroxyl groups at the terminal and / or side chains, and further having a glass transition temperature of −30 ° C. or more. 30 ° C
Less than 10% by weight of the total resin, and a resin having a glass transition temperature of 30 ° C to 90 ° C, and the melting point of the lubricant is 80 ° C to 130 ° C. the adhesion amount per one side of the resin composition layer provides a lubricating resin-treated steel sheet, wherein the dry weight is ^{0.1g / m 2 ~1.0g / m 2} .

Further, the resin is a polyester resin,
It is preferably one or more selected from the group consisting of urethane resins, epoxy resins and acrylic resins.

Further, the curing agent is preferably one or more selected from the group consisting of amine compounds, amino resins and isocyanate compounds.

Further, the organosilicon compound is preferably one or more of silicates and siloxanes represented by the following formula [I] and silane compounds represented by the following formula [II]. (In the above formula [I], R ¹ , R ² , R ³ and R ⁴
Each represents an alkyl group, an allyl group or an aryl group (these may have a substituent), and n is an integer of 12 or less. ) Formula [II] (R ⁵ ) _3-n —Si— (OR ⁶ ) _{n + 1} (In the above formula [II], R ⁵ is an alkyl group, an allyl group, an aryl group, a vinyl group, or a γ-chloropropyl group. , Γ
-Aminopropyl group, γ- (2-aminoethyl) aminopropyl group, γ-mercaptopropyl group, γ-glycidoxypropyl group, β- (3,4-epoxycyclohexyl) ethyl group or γ-methacryloxypropyl group (These may have a substituent), R ⁶ is an alkyl group or an aryl group (these may have a substituent), and n is 1 or 2. )

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The lubricating resin-treated steel sheet (hereinafter referred to as the lubricating resin-treated steel sheet) of the present invention, which is excellent in the continuous rectangular tube formability and the continuous weld spotting property, will be described in detail.

In the lubricating resin-treated steel sheet of the present invention, various known zinc or zinc-based plated steel sheets can be used as the original sheet, and there is no particular limitation. Specific examples include electrogalvanized steel sheets, electrogalvanized-nickel plated steel sheets, hot-dip galvanized steel sheets, 5% aluminum-zinc hot-dip galvanized steel sheets, and the like.

The lubricating resin-treated steel sheet of the present invention has a chromate film on both surfaces of such a zinc or zinc-based plated steel sheet. The chromate coating is not particularly limited, and any known coating type or coating formed by electrolytic chromate treatment can be used. For example, chromic anhydride,
Chromate, mainly composed of chromate and dichromic acid, and a chromium hydrate mainly formed by treating a steel sheet by a known ordinary method using a treatment liquid obtained by mixing silica such as colloidal silica into these aqueous solutions. The film is exemplified.

The coating weight of the chromate film is a metallic Cr basis, per side ^{10mg / m 2 ~200mg / m 2} , preferably from ^{30mg / m 2 ~100mg / m 2} . When the amount of the chromate coating deposited is less than 10 mg / m ² , the adhesion between the steel sheet and the resin composition layer is insufficient, so that not only the resin composition layer peels off during press working but the press formability decreases, It is not possible to obtain sufficient corrosion resistance. On the other hand, even if the amount of chromate coating adhered exceeds 200 mg / m ² , not only the corrosion resistance cannot be further obtained but also the surface appearance is deteriorated and the steel sheet is deformed by bending or press forming. When processed, the chromate coating undergoes cohesive failure, resulting in deterioration of the adhesiveness of the resin composition layer and deterioration of press formability and corrosion resistance of the pressed part.

In the lubricating resin-treated steel sheet of the present invention, a resin composition layer containing a resin, a curing agent for the resin, a lubricant and an organosilicon compound is provided on such a chromate film.

The resin that serves as the base of the resin composition layer (hereinafter referred to as
2) a resin having a plurality of hydroxyl groups at the terminals and / or side chains and having a Tg of −30 ° C. to 90 ° C.
It is a mixture of more than one species. Here, in order to obtain a sufficient effect, Tg that is different to some extent within the above Tg range.
It is necessary to prepare a base resin by combining the resins having the following formulas: a low Tg resin having a Tg of −30 ° C. or higher and lower than 30 ° C. and a high Tg resin having a Tg of 30 ° C. to 90 ° C. The base resin is prepared so that the content of the base resin is not less than wt%.

As is well known, when press molding is continuously performed at a high speed, the temperature of the mold gradually rises. Where Tg
When a resin having a low viscosity is used as the base resin of the resin composition layer, the moldability at the start of continuous press molding (the initial stage of pressing) is excellent, but the performance does not continue. On the other hand, when a resin having a high Tg is used as the base resin, good moldability is not obtained in the initial stage of pressing and press cracking occurs, but the moldability increases as the temperature of the mold rises while molding continues. Finally, good moldability is exhibited. That is, in the lubricating resin-treated steel sheet, the temperature of the mold and the steel sheet during press forming (hereinafter referred to as press temperature) is T of the resin composition layer.
In the vicinity of g, that is, in the glass transition region, the press formability becomes good.

In continuous press molding, the press temperature usually rises from room temperature to around 120 ° C. Considering this, in order to continuously realize excellent moldability from the initial stage of pressing, the Tg of the base resin needs to be in a wide range. However, the glass transition region of ordinary resins is Tg.
It is about ± 30 ° C, and if the press temperature is within this range, good press formability can be secured, but it is impossible to achieve excellent press formability in the overall press temperature from the initial press to the die heating. Is.

Therefore, in the present invention, assuming that the pressing temperature is 0 ° C to 120 ° C, the Tg is -30 ° C to 90 ° C.
Then, by mixing two or more kinds of resins having different Tg's to each other to form the base resin, excellent press formability is realized in the entire press temperature from the initial pressing to the heating of the die. When the Tg of the resin is less than -30 ° C, the resin composition layer becomes extremely soft at a high temperature, and metal contact occurs between the mold and the steel sheet substrate during continuous press molding, thereby achieving good press moldability. I can't. Conversely, resin T
When g exceeds 90 ° C., the resin composition layer is too hard at low temperature,
Cracks are likely to occur in the initial stage of pressing.

Here, in order to obtain a sufficient effect, it is necessary to combine resins having different Tg to some extent to prepare a base resin. Therefore, a low Tg resin having a Tg of -30 ° C. or higher and lower than 30 ° C., The base resin is prepared such that the high Tg resin having a Tg of 30 ° C. to 90 ° C. is contained in an amount of 10% by weight or more based on the total amount of the base resin. By setting the Tg of the low Tg resin to −30 ° C. or higher, it is possible to reliably prevent softening of the resin composition layer at high temperatures, and
By setting the temperature to be less than 30 ° C., flexibility at low temperature can be sufficiently ensured. Also, the Tg of high Tg resin is 30
When the temperature is not lower than 0 ° C, softening of the resin composition layer at high temperature can be reliably prevented, and when the temperature is not higher than 90 ° C, the flexibility at low temperature can be sufficiently ensured.
Furthermore, by setting the content of both resins to 10% by weight or more of the total (base) resin, the effect of expanding the glass transition region by the composite addition can be more reliably exhibited. Therefore, with such a configuration, a low Tg is obtained.
By the interaction between the resin and the high Tg resin, it is possible to suitably prevent the resin composition layer from softening at a high temperature and sufficiently secure the flexibility at a low temperature. Overall, extremely excellent press formability can be secured.

It is needless to say that the low Tg resin and the high Tg resin may be used by blending a plurality of kinds.

In the steel sheet treated with the lubricating resin of the present invention, the resin as the base of the resin composition layer has the above Tg, and
As long as it has a plurality of hydroxyl groups at the terminal and / or side chain, a resin using a compound having a hydroxyl group as a constitutional unit of the resin, a resin having a hydroxyl group introduced into its molecular chain by modification, etc. are widely known. All resins, especially general-purpose resins whose Tg can be easily adjusted can be used. In particular,
As long as it has a hydroxyl group in the molecular chain, polyester resins, urethane resins, epoxy resins, acrylic resins, alkyd resins, polyvinyl butyral resins, etc. are exemplified, and among them, polyester resins, urethane resins Epoxy resins and acrylic resins are preferably used. In addition, various commercially available products can be preferably used for these resins.

The resin composition layer of the lubricating resin-treated steel sheet of the present invention contains such a resin curing agent. As a matter of course, as the curing agent, a curing agent that can react only with the above resin and does not react with other mixture components is used. In the present invention, as the curing agent, one or more selected from an amine compound, an amino resin and an isocyanate compound is used, and the final reached plate temperature after 20 to 60 seconds is preferably 15 or more.
A material that can be baked and cured under conditions such as 0 ° C to 250 ° C is selected. Specifically, as the amine compound,
Polyetherdiamine, polymethylenediamine, triethylenetetramine, diethylenetriamine, metaphenylenediamine, N-aminoethylethanolamine,
4,4'-diaminodiphenylmethane, diaminodiphenylsulfone, etc .; amino resins include melamine resins, benzoguanamine resins, urea resins, etc .; isocyanate compounds such as hexamethylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate , And these polymers (polymers). The content of the curing agent is 5 to 40 parts by weight with respect to 100 parts by weight of the base resin.

The resin composition layer of the steel sheet treated with the lubricating resin of the present invention contains an organosilicon compound, not silica such as colloidal silica or silica sol. Silica (SiO ₂ ) has been often used as a means for improving the corrosion resistance of resin-treated steel sheets. For example, colloidal silica such as Snowtex-O and Snowtex-N (manufactured by Nissan Chemical Co., Ltd.), ethyl cellosolve silica sol (manufactured by Nissan Chemical Co., Ltd.)
Silica powders such as organosilica sols and vapor phase silica powders (manufactured by Aerosil Co., Ltd.) are used for steel sheets, and are common in this technical field. However, even if any of these is used, the weldability is significantly deteriorated. This is because such silica is an inorganic polymer containing a non-conductive silicon atom, and moreover, it is difficult to decompose even when the temperature rises during welding.

Further, JP-A-62-73938 and 61
-30886, JP-A-3-16726, JP-B-63
No. 2310 discloses a method of using an alkyl silicate instead of silica. In this method, in any case, a resin and an alkyl silicate are chemically bonded to each other to form a dense inorganic-organic compound. Forming a polymer,
Therefore, the resin film is not easily thermally decomposed during welding, and the thermally decomposed resin is attracted to the surface of the welding tip to attach a silicon-based decomposed product to promote wear of the tip, resulting in deterioration of continuous spot weldability.

On the other hand, the organosilicon compounds, especially the organosilicon compounds represented by the formulas [I] and [II], which will be described later, are more easily thermally decomposed than silica and the like, and are dragged by the resin to the chips. It does not adhere. Therefore,
By blending these in the resin composition layer, it is possible to obtain both a sufficient effect of improving corrosion resistance and a good spot weldability.

In the present invention, as the organosilicon compound, silicates represented by the following formula [I], siloxanes represented by the same formula [I], and One or more kinds of silane compounds represented by the formula [II] are preferably used. Among them, the silicates represented by the formula [I] and the silane compound represented by the formula [II] have a small molecular weight and are easily decomposed by heat as compared with silica, and can be particularly preferably used.

[0038] (In the above formula [I], R ¹ , R ² , R ³ and R ⁴
Each represents an alkyl group, an allyl group or an aryl group (these may have a substituent), and n is an integer of 12 or less. ) In the above formula [I], R
¹ , R ² , R ³ and R ⁴ may be the same or different from each other.

Formula [II] (R ⁵ ) _3-n —Si— (OR ⁶ ) _{n + 1} (In the above formula [II], R ⁵ is an alkyl group, an allyl group, an aryl group, a vinyl group, or γ-chloro. Propyl group, γ
-Aminopropyl group, γ- (2-aminoethyl) aminopropyl group, γ-mercaptopropyl group, γ-glycidoxypropyl group, β- (3,4-epoxycyclohexyl) ethyl group or γ-methacryloxypropyl group (These may have a substituent) and R ⁶ represents an alkyl group or an aryl group (these may have a substituent). Further, n is 1 or 2. )

Specific examples of the silicates and siloxanes represented by the above formula [I] include methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, n-butyl orthosilicate and n-octyl orthosilicate. Preferable examples are silicates such as phenyl orthosilicate, benzyl orthosilicate and phenethyl orthosilicate, allyl orthosilicate, methallyl orthosilicate, and siloxanes produced by dehydration condensation of these silicates.

Specific examples of the silane compound represented by the above formula [II] include divinyldiethoxysilane and
Divinyl-di- (β-methoxyethoxy) silane, di (γ-glycidoxypropyl) dimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, vinyltris-β-methoxyethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-
Suitable examples include mercaptopropyltrimethoxysilane and the like.

In the lubricating resin-treated steel sheet of the present invention, the content of the organosilicon compound is 5 to 80 parts by weight with respect to 100 parts by weight of the above-mentioned base resin. By setting the content of the organosilicon compound to 5 parts by weight or more, the addition effect of the organosilicon compound can be suitably expressed, and good corrosion resistance and processed part corrosion resistance can be obtained. By setting the content to 80 parts by weight or less, Further, it is possible to suitably prevent the press formability (lubricity, powdering property) and weldability from being deteriorated by the excessive addition of the organosilicon compound, and to stably obtain a steel sheet having excellent properties.

The resin composition layer of the lubricating resin-treated steel sheet of the present invention contains a lubricant in order to obtain better continuous rectangular tube molding. The lubricant that can be used is not particularly limited, and various known lubricants can be used as long as they have a melting point of 80 ° C to 130 ° C, preferably 90 ° C to 110 ° C. When the melting point of the lubricant is less than 80 ° C., the lubricant melts even on the wall surface portion at a relatively low pressure, and the slidability is uniformly improved at the flange portion. Difference occurs, and necking and wall cracks occur. When the melting point of the lubricant exceeds 130 ° C., on the contrary, the lubricant is not sufficiently melted even at the corners, and the difference in the flow of the steel sheet also makes it impossible to obtain sufficient continuous rectangular tube formability. That is, in each rectangular tube drawing, it is important that the lubricant is melted only in the high-temperature and high-temperature corners to smooth the variation in the slidability of the flange, and for that purpose, the resin composition layer The melting point of the lubricant needs to be 80 ° C to 130 ° C.

The lubricant that can be used is not particularly limited as long as it has the above melting point, and a polyolefin wax made of a polymer of an olefin hydrocarbon such as polyethylene, polypropylene and polybutene, and polytetrafluoroethylene ( Fluorine-based resins such as Teflon) and polyvinyl fluoride are preferably exemplified, and of these, one kind may be used alone, or two or more kinds may be mixed and used. Among them, polyethylene wax is particularly preferably used because it has the lowest wear rate near the melting point and has a low friction coefficient.

The blending amount of the lubricant is 100
It is 1 to 40 parts by weight with respect to parts by weight. By setting the blending amount to 1 part by weight or more, the effect of improving the lubricity can be suitably obtained, and good continuous rectangular tube formability can be realized.
By setting the content to 0 parts by weight or less, it is possible to prevent deterioration of the resin film strength due to excessive blending of the lubricant, deterioration of the appearance after press working, etc., and to stably obtain a high-quality steel plate.

In the lubricating resin-treated steel sheet of the present invention, the adhesion amount of the resin composition layer containing such a resin, a curing agent, a lubricant and an organosilicon compound is from 0.1 to 10 in terms of dry weight.
It is 1.0 g / m ² . The amount of resin composition layer deposited is 0.1 g / m ²
When it is less than the above range, the unevenness of the steel sheet surface cannot be completely filled, and the effect of improving corrosion resistance and pressability is small. Also, when it exceeds 1.0 g / m ² ,
Although it has the effect of improving the corrosion resistance, the performance related to the conductivity such as the continuous spot weldability is remarkably deteriorated and the cost is increased.

The method of manufacturing the lubricating resin-treated metal plate of the present invention will be briefly described below. First, the chromate treatment is performed on the zinc or zinc-based plated steel sheet as described above to form a chromate film. Chromate treatment may be carried out according to a usual treatment method, for example, chromic anhydride, chromate, dipping chromate treatment in an aqueous solution containing dichromic acid as a main component, electrolytic chromate treatment may be performed, and in the above aqueous solution Alternatively, a coating solution mainly containing chromium hydrate may be formed by performing a coating type chromate treatment in which a treatment liquid containing colloidal silica or the like, more preferably mixed with vapor phase silica is coated on the plated steel sheet. After treating the plated steel sheet with such a chromate treatment liquid, a chromate film is formed on both surfaces of the plated steel sheet through a step of squeezing with a flat rubber roll or the like and a drying step such as hot air drying.

Subsequently, a resin composition layer containing the above-mentioned resin, curing agent, lubricant and organosilicon compound is formed on the chromate film. First, necessary components are prepared in a predetermined amount, and these are mixed and dispersed using a suitable solvent as necessary to prepare a physically uniform resin mixture (paint). This mixture is applied to a plated steel sheet on which a chromate film has been formed by a known ordinary method such as roll coating, spray coating, dip coating, and brush coating so that a predetermined adhesion amount is obtained, and usually at about 50 to 180 ° C. The lubricating resin-treated steel sheet of the present invention can be obtained by drying for 3 to 90 seconds.

Although the lubricating resin-treated steel sheet excellent in continuous rectangular tube formability and continuous welding point property of the present invention has been described in detail above, the present invention is not limited to the above examples and deviates from the gist of the present invention. It goes without saying that various changes and improvements may be made within the range not covered.

[0050]

EXAMPLES Next, the present invention will be described more specifically based on examples.

[Example] Various plated steel sheets shown in the following A to C were prepared. In addition, the plating adhesion amount is the adhesion amount per one surface. A. Electrogalvanized steel sheet Thickness 0.8mm Zinc coating amount 20g / m ² B. Electric zinc / nickel plated steel sheet 0.8 mm thickness Zinc / nickel plated amount 20
g / m ² C, hot-dip galvanized steel sheet 0.8 mm thick, zinc coating amount 60 g / m ²

On both sides of such plated steel sheet, CrO ₃
A chromate treatment solution having a composition of 20 g / L and Na ₃ AlF ₅ 4 g / L was spray-coated, squeezed with a flat rubber roll, and dried with hot air. The amount of the chromate coating adhered was adjusted by the spray treatment time. The amount of chromate coating deposited (per surface) is shown in Table 1 below.

A resin mixture (paint) containing the following resin, curing agent, organosilicon compound, and lubricant in the proportions shown in Table 1 was prepared, and a chromate film was formed on the plated steel sheet as described above. The resin composition layer is applied to both surfaces by a roll coating method so that the amount of adhesion per surface becomes a predetermined amount, and then heated and dried under the condition that the reached plate temperature after 20 seconds becomes 150 ° C. Formed, Table 1
Various types of lubricating resin-treated steel sheets as shown in 1 were produced. Table 1 shows the amount of the resin composition layer deposited on one surface and the type of the plated steel sheet serving as the original sheet.

<Resin> Epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd. Epicoat 1009 Tg;
15 ° C. Alkyd resin Mitsui Toatsu Chemical Co., Ltd. Ulix Tg; 80 ° C. Acrylic resin Mitsui Toatsu Chemical Co., Almatex 749 Tg; 80
℃ Urethane polyol resin Toyobo Co., Ltd. UR Tg; -45 ℃ ~ 100 ℃ Butyral resin Denki Kagaku Kogyo Denka Butyral Tg; 80 ℃ polyester resin Mitsui Toatsu Kagaku Almatex P645 Tg; 8
0 ° C Note that the urethane polyol resin (U manufactured by Toyobo Co., Ltd.
As R), 10 kinds having different Tg's were prepared depending on the difference in molecular weight.

<Curing Agent> a Isocyanate compound Coronate 2507 manufactured by Nippon Polyurethane Industry Co., Ltd. b Melamine resin Cymel 303 manufactured by Mitsui Cyanamid Co., Ltd.

<Organosilicon compound> 1. Ethyl silicate Ethyl silicate 40 manufactured by Nippon Corcoat Chemicals 2. γ-methacryloxypropyltrimethoxysilane KBM503 manufactured by Shin-Etsu Chemical Co., Ltd. 3. Colloidal silica (Comparative example) Nissan Chemical Industries Snowtex-N

<Lubricant> Polyethylene wax Mitsui High Wax manufactured by Mitsui Petrochemical Co., Ltd. Melting point: 10
5 to 127 ° C. The polyethylene wax was prepared by melting it in a solvent of xylene or toluene under heating and then adjusting the particle size by changing the cooling rate to prepare the wax having various melting points.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

The following tests were conducted on such various types of lubricating resin-treated steel sheets.

<Square Cylindrical Drawing Test> Oil-free test pieces were processed by an Erichsen square tube drawing tester while changing the wrinkle holding pressure, and the limit wrinkle holding pressure was obtained. Press conditions Wrinkle pressing pressure 1 to 9 tons Punch diameter 40 mm x 40 mm Blank diameter 93 mm φ Drawing speed 250 mm / s Mold temperature 0 to 120 ° C In this test, at normal temperature (25 ° C) and temperature at continuous pressing (100 The limit of the wrinkle holding pressure (° C) was used to evaluate the drawability of the rectangular tube.

<Continuous weldability test> Radius type (10 mm
φ, 100 mmR) electrode, applied pressure: 190 kg, current: 7.8 kA, energization cycle: 13 cycles, continuous dot test is performed, nugget diameter is measured, and nugget diameter is 4 × (t) ) I calculated the maximum number of RBIs that would not reach ^-1 . The above results are shown in Table 2 below.

[0064]

[0065]

[0066]

[0067]

As described above in detail, according to the present invention, since the lubricity during press working is good,
Even in the case of continuous rectangular tube molding, it is possible to perform the processing as it is without using lubricating oil such as press oil during pressing, and since it also has sufficient electrical conductivity, continuous spot weldability and grounding are possible. A lubricated resin-treated steel sheet having excellent properties can be realized. In addition, since the lubricating oil application work and the degreasing work at the time of press working can be omitted, the manufacturing cost can be greatly reduced.

Claims (4)

[Claims] 1. The amount of adhesion per surface of zinc or zinc-based plated steel sheet is 10 mg / m ^{2 to} 20 in terms of metallic chromium.
A lubricating resin-treated steel sheet having a chromate film of 0 mg / m ² and having a resin composition layer thereon, wherein the resin composition layer is 5 to 40 parts by weight of a curing agent with respect to 100 parts by weight of the resin. A glass transition temperature of −30 ° C. to 90 ° C., which contains 1 to 40 parts by weight of a lubricant, and 5 to 80 parts by weight of an organosilicon compound, and the resin has a plurality of hydroxyl groups at terminals and / or side chains. A resin having two or more kinds of resins and having a glass transition temperature of −30 ° C. or higher and lower than 30 ° C. and a resin having a glass transition temperature of 30 ° C. to 90 ° C.
Each of them is contained in an amount of 10% by weight or more in the total resin, the melting point of the lubricant is 80 ° C. to 130 ° C., and the adhesion amount of the resin composition layer on one side is 0.1 g as a dry weight. / m ^{2 to} 1.0 g / m ² is a lubricating resin-treated steel sheet. 2. The lubricating resin-treated steel sheet according to claim 1, wherein the resin is one or more selected from the group consisting of polyester resins, urethane resins, epoxy resins and acrylic resins. 3. The curing agent selected from the group consisting of amine compounds, amino resins and isocyanate compounds.
The lubricating resin-treated steel sheet according to claim 1 or 2, which is the above. 4. The organosilicon compound is one or more of silicates and siloxanes represented by the following formula [I] and silane compounds represented by the following formula [II]. 4. The lubricating resin-treated steel sheet according to any one of 4 above. (In the above formula [I], R ¹ , R ² , R ³ and R ⁴
Each represents an alkyl group, an allyl group or an aryl group (these may have a substituent), and n is an integer of 12 or less. ) Formula [II] (R ⁵ ) _3-n —Si— (OR ⁶ ) _{n + 1} (In the above formula [II], R ⁵ is an alkyl group, an allyl group, an aryl group, a vinyl group, or a γ-chloropropyl group. , Γ
-Aminopropyl group, γ- (2-aminoethyl) aminopropyl group, γ-mercaptopropyl group, γ-glycidoxypropyl group, β- (3,4-epoxycyclohexyl) ethyl group or γ-methacryloxypropyl group (These may have a substituent), R ⁶ is an alkyl group or an aryl group (these may have a substituent), and n is 1 or 2. )