JP5517244B2 - Alkali-soluble lubricating metal plate excellent in press formability and alkali film removal property and method for producing the same - Google Patents

Description

  The present invention relates to a metal plate having a surface on which is formed a lubricating film capable of improving the press formability and a film capable of alkali film removal, which is inferior in press formability such as a titanium plate, The present invention relates to an alkali-soluble lubricating metal plate that is less likely to be defective even when subjected to complicated and severe press molding for application to a heat exchanger or the like.

  2. Description of the Related Art Conventionally, a method of laminating a lubricating film containing a resin on the surface of a metal plate is known in order to improve the lubrication performance during press working. However, since such a lubricating coating adversely affects electrodeposition coating properties, it is also possible to peel the coating in an alkali cleaning step after press working and before electrodeposition coating. A resin-coated steel sheet having a resin film excellent in press formability and alkali film removal properties is disclosed.

  In recent years, as user needs have diversified and the required characteristics of thinning and lightening metal members have become increasingly severe, press forming has been performed to process a single metal plate into a complex shape. I came. Further, as a metal plate, it has been desired to press-form not only a steel plate having relatively excellent press formability but also a titanium plate having inferior press formability into a complicated shape.

  Titanium plate has excellent properties not found in other metals, such as corrosion resistance that does not corrode in seawater, and excellent specific strength despite being lightweight, such as aerospace and chemical plants It is used in a wide range of fields such as watches and eyeglass frames. In particular, in the chemical plant field, due to the excellent corrosion resistance of titanium plates, they are used in seawater heat exchangers and the like. In this case, for example, in a plate heat exchanger, the surface of the plate material is press-molded into a very complicated shape to increase the surface area, thereby improving the heat transfer efficiency. However, there is a problem that the surface shape is limited.

  That is, the elongation characteristic in the rolling direction (longitudinal direction; L direction) of the titanium plate is good as it is, but the elongation characteristic is inferior to the direction orthogonal to the rolling direction (width direction; C direction), Combined with the anisotropy of the elongation properties, if a titanium plate is pressed into a complicated shape, it will break.

  In order to improve the press formability of the titanium plate, there is also a method of generating an oxide film on the surface of the titanium plate (Patent Document 2 etc.) and a method of causing a TiC-containing layer to exist on the surface of the titanium plate (Patent Document 3 etc.) Although it has been studied, the formability is insufficient to cope with the recent severe press molding.

JP 2007-98599 A JP-A-6-173083 JP 2006-291362 A

In consideration of the above circumstances, the present invention provides an alkali film that can be formed into a complicated shape by applying a lubricant film that can be removed with an alkali to a metal plate that is inferior in press formability such as a titanium plate. The provision of a fusible lubricating metal plate was raised as an issue.

  The present invention that has solved the above problems is a metal plate provided with an alkali-soluble lubricating film obtained from a surface treatment composition, wherein the surface treatment composition comprises an α, β-ethylenically unsaturated carboxylic acid. A copolymer (A) synthesized from a monomer component comprising a structural unit (A-1) derived from styrene and a structural unit (A-2) derived from an α, β-ethylenically unsaturated carboxylic acid ester And a colloidal silica (B) having a particle diameter of 40 to 50 nm and a wax mixture (C) comprising a spherical polyethylene wax having an average particle diameter of 1 μm and a spherical polyethylene wax having an average particle diameter of 0.6 μm. And an alkali-soluble lubricating metal plate excellent in alkali film removal properties.

  The wax mixture (C) is 30 to 50 masses of spherical polyethylene wax having an average particle diameter of 0.6 μm in a total of 100 mass% of spherical polyethylene wax having an average particle diameter of 1 μm and spherical polyethylene wax having an average particle diameter of 0.6 μm. %, And these all preferably have a softening point of 113 to 132 ° C.

  Both the static friction coefficient and the dynamic friction coefficient on the surface of the alkali-soluble lubricating film are 0.15 or less, and the value when the dynamic friction coefficient is subtracted from the static friction coefficient is -0.02 to +0.02. And the press formability is further improved.

When the total amount of the copolymer (A), the colloidal silica (B) and the wax mixture (C) is 100% by mass, the surface treatment composition is 70 to 90% by mass of the copolymer (A), colloidal An embodiment in which 5 to 20% by mass of silica (B) and 3.5 to 10% by mass of wax mixture (C) are contained, derived from the α, β-ethylenically unsaturated carboxylic acid of copolymer (A) The structural unit (A-1) is a structural unit derived from methacrylic acid, and the structural unit (A-1) derived from an α, β-ethylenically unsaturated carboxylic acid and an α, β-ethylenically unsaturated carboxylic acid ester An embodiment in which the structural unit (A-1) derived from the α, β-ethylenically unsaturated carboxylic acid is 20 to 40% by mass in a total of 100 mass% of the structural unit (A-2) derived from the copolymer, a copolymer A state in which the acid value of (A) is 150 mgKOH / g or more Are all suitable embodiments of the present invention. Moreover, it is also preferable that the adhesion amount of the alkali-soluble lubricating film is 0.6 to 1.5 g / m ² .

  The present invention is a method for producing the above alkali-soluble lubricating metal plate, wherein the surface treatment composition of the present invention is applied to the metal plate and then dried at a plate temperature of 100 to 130 ° C. In this case, the metal plate is most preferably a pure titanium plate or a titanium alloy plate.

  According to the present invention, the press formability of a metal plate inferior in press formability such as a titanium plate can be remarkably improved. Therefore, the alkali-soluble lubricating metal plate of the present invention can be applied to various uses such as chemical plant fields such as heat exchangers, and other moving medium members such as home appliances, building materials, ships and automobile parts. is there.

It is the figure which represented typically the presence state of the wax in the lubricating film of this invention. It is explanatory drawing of the evaluation place of press formability in this invention.

The alkali-soluble lubricating metal plate of the present invention is characterized in that a lubricating film using two types of wax having a specific particle diameter is laminated on the surface of the metal plate. Hereinafter, each component will be described.

[Original plate]
As described above, a titanium plate (including a titanium alloy plate) that is inferior in press formability as the original plate is optimal as the original plate in the alkali-soluble lubricating metal plate of the present invention. However, an aluminum plate, a copper plate, a cold-rolled steel plate, a hot-dip galvanized steel plate, an electrogalvanized steel plate, an alloyed hot-dip galvanized steel plate or the like may be used as the original plate in order to further improve press formability.

  The titanium plate is assumed to be an industrially pure titanium plate (JIS: 1 type or 2 types), but a titanium alloy plate containing a small amount of alloy elements to the extent that press formability is not impaired is also used. Is possible. For example, inclusion of elements such as aluminum, silicon and niobium is effective in increasing the strength of the titanium alloy plate, but as the content of these elements increases, the strength becomes too high, and the present invention Since the expected press formability cannot be obtained, the content of these elements (the total content of one or more types) is preferably about 2%. Moreover, although iron is normally contained as an unavoidable impurity, the titanium alloy plate which increased the intensity | strength by positively containing up to about 1.5% of Fe can also be applied.

  In a titanium plate (hereinafter also including a titanium alloy plate), the other components (the remainder) are titanium and inevitable impurities. Inevitable impurities are impurity elements inevitably contained in titanium sponge raw material of titanium plate, and typically include oxygen, iron (except when iron is actively added), carbon, nitrogen, There are hydrogen, chromium, nickel and the like, and elements that may be incorporated into the product in the manufacturing process are also included in the inevitable impurities.

  The thickness of the titanium plate is preferably about 0.3 to 1 mm. If the plate thickness becomes too large, it becomes difficult to exhibit the effect of improving the formability by applying the lubricating film. In other words, if the plate thickness is large, cracks will not be caused by local deformation of the plate if it is a very small high plastic strain region, but if a lubricating film is applied, on the contrary, a relatively large high plastic strain region that cannot be relaxed by local deformation May be formed and may lead to cracking. For these reasons, the thickness of the titanium plate is preferably 1.0 mm or less. The lower limit of the thickness of the titanium plate may be set in consideration of the required strength and the like, and differs depending on the type of the titanium plate. For example, in the case of industrial pure titanium (1 type or 2 types), it is 0. The thickness is preferably about 3 mm or more, and in the case of a titanium alloy containing a small amount of alloy elements, it may be thinner.

[Copolymer for lubricating film (A)]
The alkali-soluble lubricating metal plate of the present invention has a lubricating film formed on one side or both sides of the original plate. This lubricating coating essentially comprises a structural unit (A-1) derived from α, β-ethylenically unsaturated carboxylic acid and a structural unit (A-2) derived from α, β-ethylenically unsaturated carboxylic acid ester. It is a film | membrane obtained from the surface treatment composition which contains the copolymer (A) contained naturally as a resin component.

  The structural unit (A-1) derived from the α, β-ethylenically unsaturated carboxylic acid is used for introducing a carboxyl group into the copolymer (A), whereby the alkali of the copolymer (A) is obtained. It has the effect of enhancing the solubility in an aqueous solution and, as a result, enhancing the film removal property of the lubricating film. The α, β-ethylenically unsaturated carboxylic acid for forming the structural unit (A-1) is not particularly limited, and examples thereof include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid, Mention may be made of dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid or their monoesters. These can use 1 type (s) or 2 or more types. Of these, methacrylic acid is most preferred.

  The amount of the structural unit (A-1) is preferably 20 to 40% by mass in a total of 100% by mass with the structural unit (A-2), and the unit used for synthesizing the copolymer (A). It is preferable that 20 to 40% by mass of 100% by mass of the monomer is the α, β-ethylenically unsaturated carboxylic acid. If the amount of unsaturated carboxylic acid is less than 20% by mass, the alkali film removal property may be insufficient. On the other hand, if the unsaturated carboxylic acid is used in excess of 40% by mass, the strength as the lubricating film is deteriorated and the film is liable to be peeled off during press working, which is not preferable. The amount of the structural unit (A-1) is more preferably 25 to 35% by mass.

  When the structural unit (A-1) is in the above range, the acid value of the copolymer (A) is about 150 to 300 mgKOH / g. The amount of carboxyl groups per 1 g of copolymer (A) corresponds to about 2.69 to 5.37 mmol. A more preferable range of the acid value is 150 to 250 mgKOH / g.

  The structural unit (A-2) derived from the α, β-ethylenically unsaturated carboxylic acid ester is a base of the copolymer (A) and affects the adhesion to the metal plate and the lubricity. In addition, the structural unit (A-2) is an ester and hydrolyzes with an aqueous alkali solution, which can contribute to the removal of the lubricating film.

  The α, β-ethylenically unsaturated carboxylic acid ester for forming the structural unit (A-2) is not particularly limited. For example, methyl acrylate, ethyl acrylate, butyl acrylate isomers (for example, acrylic acid i -Butyl, etc.), 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isobonyl acrylate, N, N-dimethylaminoethyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, acrylic acid 2 -Hydroxyethyl, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, lauryl acrylate, n-stearyl acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane acrylate, 1,9-nonanediol acrylate, etc. Acrylic ester, Methyl methacrylate, ethyl methacrylate, butyl methacrylate isomers (eg n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate), 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, methacryl Tridecyl acid, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-methoxyethyl methacrylate, methacrylic acid 2-ethoxyethyl, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1, methacrylic acid 1, - hexanediol dimethacrylate, polypropylene glycol, trimethylolpropane trimethacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, trifluoroethyl methacrylate, and methacrylic acid esters such as methacrylic acid heptadecafluorodecyl is. These can use 1 type (s) or 2 or more types. Among these, a monofunctional monomer is preferable, and (meth) acrylic acid ethyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid n-butyl and the like are preferable.

The copolymer (A) may be synthesized by further using a monomer other than the monomer forming the structural unit (A-2), but the adhesion to the metal plate, the flexibility of the lubricating film and the lubrication In view of the property or film removal property, the copolymer (A) is preferably composed of the structural unit (A-1) and the structural unit (A-2). Therefore, it is preferable that a structural unit (A-2) is 60-80 mass% in 100 mass% of copolymers (A). More specifically, the unsaturated carboxylic acid is added in an amount of 20 to 40 in a total of 100% by mass of the unsaturated carboxylic acid for the structural unit (A-1) and the unsaturated carboxylic acid ester for the structural unit (A-2). Mass%, and unsaturated carboxylic acid ester is 60 to
It is preferable to use 80% by mass.

  The method for synthesizing the copolymer (A) is not particularly limited, but emulsion polymerization is preferred from the viewpoint of easily obtaining an aqueous surface treatment composition and being environmentally friendly. The emulsion polymerization can be performed by a known method. For example, the emulsion polymerization is performed in water using a water-soluble polymerization initiator such as ammonium persulfate and an emulsifier. The emulsifier is not particularly limited, but a reactive emulsifier having an ethylenically unsaturated group in the molecule can also be used.

  The number average molecular weight of the copolymer (A) is preferably 10,000 or more, more preferably 12,000 or more, still more preferably 15,000 or more, preferably 30,000, from the viewpoint of lubricity and film removal. 000 or less, more preferably 25,000 or less, and still more preferably 20,000 or less.

  Moreover, it is preferable that the glass transition temperature (Tg) of a copolymer (A) is -40-100 degreeC. When Tg is lower than −40 ° C., the lubricating film is tacky, which may cause troubles such as dust adhesion and blocking. On the other hand, if the temperature exceeds 100 ° C., the lubricating film becomes brittle, which may cause film peeling during press working.

  In the present invention, the copolymer (A) is not neutralized in the surface treatment composition for forming a lubricating film. Therefore, no alkali compound is added to the reaction solution during emulsion polymerization, the emulsion after polymerization, and the surface treatment composition. Since the aqueous dispersion of the wax mixture (C) is alkaline, the “alkali compound” does not include the wax mixture (C). Since the copolymer (A) has a carboxyl group, when the surface treatment composition is prepared using the emulsion after completion of the polymerization, the pH becomes an acidic region of about 1.7 to 4.

  The amount of the copolymer (A) in the surface treatment composition is 70 to 70% when the total of the copolymer (A), colloidal silica (B; solid content) and the wax mixture (C) is 100% by mass. It is preferable to set it as 90 mass%. If it is less than 70% by mass, the film forming property of the lubricating film may be lowered, or the wax mixture (C) may not be retained or coated in the lubricating film, which is not preferable. On the other hand, if it exceeds 90% by mass, the amount of silica (B) and wax mixture (C) is relatively small, so that the lubrication performance is lowered, and there is a risk of film peeling or the like during press molding.

[Colloidal silica for lubricating coating (B)]
Colloidal silica (B) is contained as an essential component in the surface treatment composition for forming the lubricating film of the alkali-soluble lubricating metal plate of the present invention. This is because the colloidal silica (B) is blended to improve press moldability. The colloidal silica (B) used in the present invention has a particle diameter of 40 to 50 nm. When the particle diameter is less than 40 nm, the specific surface area is increased and the activity is increased, so that the storage stability of the composition is deteriorated by aggregation in the surface treatment composition, and the alkali film removal property of the lubricating film is also improved. Since it falls, it is not preferable. When the particle diameter exceeds 50 nm, precipitation occurs while the surface treatment composition is stored, and it is not preferable because it cannot be redispersed even if stirred. Moreover, since press moldability will fall even if a deposit arises slightly, it is preferable to use colloidal silica (B) with a particle diameter of 40-50 nm.

  Since the surface treatment composition used in the present invention is acidic with a pH of about 1.7 to 4 as described above, it is preferable to use an acidic colloidal silica (B). When colloidal silica on the alkali side is used, gelation may occur during the preparation of the surface treatment composition. Acidic colloidal silica (B) having a particle size of 40 to 50 nm is available from Nissan Chemical Industries as “Snowtex (registered trademark) OL”. In addition, a particle diameter is an average particle diameter by BET method.

  The amount of colloidal silica (B; solid content) in the surface treatment composition is 5 to 20 masses when the total of the copolymer (A), colloidal silica (B) and wax mixture (C) is 100 mass%. % Is preferable. If the amount is less than 5% by mass, the effect of improving the film removal property and press moldability may be insufficient. If it exceeds 20% by mass, the press formability tends to decrease, and the stability of the surface treatment composition also decreases.

[Wax mixture for lubricating coating (C)]
The surface treatment composition for forming the lubricating film of the alkali-soluble lubricating metal plate of the present invention contains a wax mixture (C). In the present invention, spherical polyethylene wax (hereinafter referred to as C-1) having an average particle diameter of 1 μm and spherical polyethylene wax (hereinafter referred to as C-2) having an average particle diameter of 0.6 μm are mixed and used. As shown in FIG. 1, a mixture of the two is used to form a protrusion on the surface of the lubricating film with wax (C-1) having an average particle diameter of 1 μm to improve the lubricity of the surface and to be buried inside the film. This is because the wax (C-2) having an average particle diameter of 0.6 μm exhibits a lubricating effect when the metal plate flows into the concave portion of the mold during press molding. In either case, the press formability is insufficient, and even if a wax having an average particle diameter of more than 1 μm is used, the lubricating effect is low. Even when a fluorine-based lubricant was used, the lubricating effect was low.

  Thus, in the present invention, a metal plate is obtained by using a combination of a wax (C-1) having an average particle diameter larger than the film thickness and a wax (C-2) having an average particle diameter smaller than the film thickness. The initial lubricity when flowing into the recess of the mold is expressed by wax (C-1), and the lubricity when the metal plate flowing into the recess slides with the mold is expressed by wax (C-2). It is characterized by its expression. The film thickness will be described later.

  In the present invention, as shown in FIG. 1, both the wax (C-1) and the wax (C-2) are required to maintain a spherical shape in the lubricating film. If the wax melts and bleeds out on the surface of the lubricant film during press molding, the effect of using the two types of waxes together will not be exhibited. At the time of press molding, since the metal plate is heated to about 120 to 130 ° C. by frictional heat with the mold, in the present invention, the waxes (C-1) and (C-2) both have a softening point of 113 to It is preferable to use polyethylene wax at 132 ° C. Thereby, press molding can be performed in the region having the most excellent lubricity in which solid lubrication and liquid lubrication are mixed.

  Examples of such wax (C-1) include Chemipearl (registered trademark) “WF-640” (softening point 113 ° C.) and “W-700” (softening point 132 ° C.) manufactured by Mitsui Chemicals, Ltd. As C-2), there are also Chemipearls “W-950” (softening point 113 ° C.) and “W-900” (softening point 132 ° C.). These are all aqueous dispersions of wax particles. The average particle diameter of the wax is determined by the Coulter counter method, and the softening point is determined by the ring and ball method. The wax (C-1) has a volume average particle size in the range of 0.9 μm to 1.4 μm, and the wax (C-2) has a volume average particle size of 0.45 μm to 0.8 μm. Is in range. Therefore, in the wax mixture (C) used in the present invention, the multimodal particle size has one peak between 0.9 μm and 1.4 μm and one peak between 0.45 μm and 0.8 μm. Show the distribution. For this reason, it becomes a film structure of the form as shown in FIG. 1, and shows a good lubricity.

  The mixing ratio of the wax (C-1) and the wax (C-2) is 50 to 70% by mass of the wax (C-1) and 30 to 50% of the wax (C-2) with respect to the total of 100% by mass of both. It is preferable to set it as the mass% (all are solid content). When the amount of wax (C-2) is less than 30% by mass, the lubrication effect by the wax (C-2) inside the film is not sufficiently exhibited, and the lubricity in the depth direction of the film is insufficient, and the mold There is a risk of film peeling (cohesive failure in the sliding direction) due to sliding. On the other hand, if the wax (C-2) exceeds 50% by mass, the amount of the wax (C-1) is decreased, the lubricating effect on the coating surface is lowered, and the press formability may be lowered.

The amount of the wax mixture (C) in the surface treatment composition is 3.5 to 10% by mass when the total of the copolymer (A), colloidal silica (B) and the wax mixture (C) is 100% by mass. It is preferable that As the wax concentration in the lubricating film is increased, the dynamic friction coefficient greatly decreases at about 1% by mass, becomes almost flat at 3.5% by mass, then decreases gradually, and is constant at about 10% by mass. The value comes to show. Therefore, the wax mixture (C) is preferably 3.5% by mass or more, more preferably 5% by mass or more. Even if added over 10% by mass, the effect of reducing the dynamic friction coefficient is saturated, so the upper limit is preferably 10% by mass. Further, when the amount of the wax mixture (C) increases, foaming becomes violent when the surface treatment composition is applied to the metal plate, making it difficult to obtain a uniform film. This is probably because a surfactant is contained in the aqueous dispersion of wax. The wax mixture (C) is more preferably 8% by mass or less.

  By using two kinds of waxes together as described above, the static friction coefficient and the dynamic friction coefficient of the lubricating film of the alkali-soluble lubricating metal plate of the present invention are close to each other. Specifically, both the static friction coefficient and the dynamic friction coefficient of the lubricating film are 0.15 or less, and the value when the dynamic friction coefficient is subtracted from the static friction coefficient is -0.02 to +0.02. Is preferred. Within this range, the resistance of the lubricating film until the metal plate flows into the recess of the mold and elongation occurs is reduced, and the static friction coefficient and the dynamic friction coefficient are comparable, so the rolling direction during press forming And molding defects (necking and cracking) caused by the difference in elongation in the width direction can be further suppressed. As a result, it is possible to perform processing even in press molding into a complicated shape such as a plate heat exchanger.

[Amount of lubricant coating]
In the present invention, as shown in FIG. 1, the lubricating coating forms convex portions of wax (C-1) having a large average particle diameter, and therefore it is difficult to simply represent μm. As shown in FIG. 1, in order to form a convex part on the surface of the film with the wax (C-1) having an average particle diameter of 1 μm, the amount of the adhered film should be 0.6 to 1.5 g / m ^2. preferable. If the coating amount is less than 0.6 g / m ² , the lubricity cannot be exhibited and the coating peels off, which may cause galling or cracking. On the other hand, when it exceeds 1.5 g / m ² , the alkali film-removing property of the film is lowered,
There is a possibility that the pH of the alkaline degreasing solution is lowered to reduce the ability of the degreasing solution, which is not preferable.

[Surface treatment composition]
In order to prepare the surface treatment composition of the present invention, for example, the copolymer (A) is synthesized by emulsion polymerization, and the resulting emulsion is added to a colloidal silica (B) that is an aqueous dispersion and a wax mixture (C ), That is, a method in which an aqueous dispersion of wax (C-1) and an aqueous dispersion of wax (C-2) are added and mixed well. The surface treatment composition may be diluted or concentrated to obtain a viscosity suitable for coating.

  Various known additives used in the field of resin-coated metal sheets, such as pigments such as titanium oxide, matting agents, rust preventives, anti-settling agents, etc., to the surface treatment composition as long as the object of the present invention is not impaired. May be added.

  The method for applying the surface treatment composition to the original plate is not particularly limited, and a bar coater method, a roll coater method, a spray method, a curtain flow coater method, and the like can be employed. Although drying is performed after application, in order to maintain the particle state of the wax mixture (C), heat drying at a high temperature should be avoided. Specifically, it is preferable to perform heat drying at 100 to 130 ° C. The original plate may be subjected to known surface treatments (primary treatments) such as chromate treatment, non-chromate treatment, and phosphate treatment in advance for the purpose of improving corrosion resistance and adhesion to the lubricating film. Good.

  The present invention will be described in more detail with reference to the following examples. However, the following examples are not intended to limit the present invention, and modifications within the scope of the present invention are included in the present invention. Hereinafter, “part” indicates “part by mass”, and “%” indicates “% by mass”. Moreover, the evaluation method used in the Example is as follows.

[Evaluation method]
(1) Coefficient of friction A surface treatment composition is applied to a metal plate, dried, and then a surface property measuring instrument (TYPE; 14DR) manufactured by Shinto Chemical Co., Ltd.
The SUS ball was slid while being pressed with a constant load using a, and the static friction coefficient and the dynamic friction coefficient were measured under the following conditions.

Test load: 500gf
Sliding speed: 100mm / min
Sliding distance: 40mm
Number of tests: n = 3
Sliding jig: SUS ball 10mmφ
Measurement temperature: Room temperature (20 ° C)

(2) Press formability 100 mm × 100 mm, pitch 10 mm, maximum height 4 mm, curvature radius R = 0.4, 0.6, 0.8, 1.0, simulating the heat exchange part of a plate heat exchanger , 1.4, and 1.8 mm, and using a die having six types of ridgelines, pressing was performed with an 80-ton hydraulic press. The press conditions are a maximum load of 300 kN, a press speed of 1 mm / sec, and a 4 mm press cut. About the obtained press-molded product, the crack state was evaluated at 36 crack measurement points. As shown on the left side of FIG. 2, for A, B, C, D, and E, 30 points of intersections of ridges and wavy lines and as shown on the right side of FIG. .

Regarding A, C, C ′, and E, which are the starting points of cracking, 2 points if sound (cracking or necking is not recognized), 1 point if there is a tendency to necking (necking phenomenon), 0 points if cracking occurs As a numerical value by the following formula (1).
F (i, j) = 1.0 × (healthy 2, necking 1, crack occurrence 0) (1)

For B and D, 1 point (0.5 × 2) if healthy (no cracking or necking is recognized), 0.5 point (0.5 × 1) if there is a tendency to necking (constriction phenomenon), If cracking occurred, it was converted into a numerical value by the following formula (2) as 0 point.
G (i, j) = 0.5 × (healthy 2, necking 1, crack occurrence 0) (2)

  Then, the number of points is multiplied by the reciprocal of the radius of curvature R of the ridge (each radius of curvature is represented by R (k)) to quantify the state of cracking, and that value and the value when no cracking occurs throughout The ratio to (the denominator in the formula (3)) is obtained by the following formula (3), and used as the “score” of the press formability as an index for evaluating the press formability in the present invention. The higher the score, the better the press molding. In equations (1) to (3), i represents a place and j represents a score. Therefore, R (k) is one of 0.4, 0.6, 0.8, 1.0, 1.4, and 1.8.

(3) Alkali film-removing property In order to evaluate the film-removing property of the lubricating film in the alkaline degreasing process, a test material in which the adhesion amount V ₀ (g / m ² ) of the lubricating film adhering to the metal plate was measured. After immersing in a 20 g / L solution of an alkaline degreasing agent adjusted to 60 ° C. (“CL-N364S” manufactured by Nihon Parkerizing Co., Ltd.) for 2 minutes, washing with water and drying, the coating amount was set to V ₁ (g / m ² ) Was measured, and the film removal rate (%) of the film was determined by the following formula (4).

  The evaluation criteria were ◎ for a film removal rate of 100%, ○ for a film removal rate of 95% or more and less than 100%, Δ for a film removal rate of 90% or more and less than 95%, and × for a film removal rate of less than 90%.

The coating amount (g / m ² ) was determined by quantifying the amount of Si element in the coating using a fluorescent X-ray apparatus (“MIF-2100” manufactured by Shimadzu Corporation) and using the following conversion formula (5). .

Here, Si is the amount of Si element in the film (mg / m ² ), C is the addition concentration (%) of SiO ₂ in the surface treatment composition, 28 is the element amount of Si, and 60 is the molecular weight of SiO _2. .

Synthesis example 1
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel was charged with 400 parts of water, and the temperature was raised to 80 ° C. while purging with nitrogen. An aqueous initiator solution in which 0.4 part of ammonium persulfate is dissolved in 200 parts of water, 60 parts of methacrylic acid as an unsaturated carboxylic acid, 77.4 parts of n-butyl methacrylate as an unsaturated carboxylic acid ester, and acrylic acid 2 -Put 65.6 parts of ethylhexyl, 200 parts of water, and 15 parts of a reactive surfactant "Latemul (registered trademark) S-180" (manufactured by Kao Corporation) and emulsify the pre-emulsion into separate dropping funnels. It was dripped simultaneously over 1 hour. After completion of the dropwise addition, the mixture was aged at 80 ° C. for 1 hour, cooled to 40 ° C., and then filtered through a 150 mesh wire netting. 1 was obtained.

Synthesis example 2
A copolymer emulsion No. 1 was prepared in the same manner as in Synthesis Example 1 except that the unsaturated carboxylic acid ester was only 140 parts of ethyl acrylate. 2 was obtained.

Synthesis example 3
A copolymer emulsion No. 1 was prepared in the same manner as in Synthesis Example 2 except that 40 parts of methacrylic acid and 150 parts of ethyl acrylate were used. 3 was obtained.

Synthesis example 4
A copolymer emulsion No. 1 was prepared in the same manner as in Synthesis Example 2 except that 80 parts of methacrylic acid and 130 parts of ethyl acrylate were used. 4 was obtained.

Synthesis example 5
A copolymer emulsion No. 1 was prepared in the same manner as in Synthesis Example 4 except that 90 parts of methacrylic acid was used. 5 was obtained.

Synthesis Example 6
A copolymer emulsion No. 1 was prepared in the same manner as in Synthesis Example 3 except that 30 parts of methacrylic acid was used. 6 was obtained.

Synthesis example 7
Emulsion polymerization was carried out in the same manner as in Synthesis Example 2. After aging for 1 hour at 80 ° C., about 10 parts of a 50% aqueous solution of triethylamine was gradually added dropwise until the pH reached 6, and aging was continued for 30 minutes. Thereafter, the mixture was cooled and filtered in the same manner as in Synthesis Example 1, and the copolymer emulsion No. 7 was obtained.

Synthesis example 8
A copolymer emulsion No. was prepared in the same manner as in Synthesis Example 2 except that 180 parts of methacrylic acid and 20 parts of ethyl acrylate were changed. 8 was obtained.

  The composition and properties of each copolymer are summarized in Table 1.

Experimental example 1
Emulsified solution No. of the copolymer produced in Synthesis Examples 1-8. 1-8, colloidal silica having a particle size of 40-50 nm (“Snowtex (registered trademark) OL”; manufactured by Nissan Chemical Industries), spherical polyethylene wax having an average particle size of 1 μm (“Chemipearl (registered trademark) W— 700 ”; softening point 132 ° C .; manufactured by Mitsui Chemicals, Inc.), spherical polyethylene wax having an average particle diameter of 0.6 μm (“ Chemipearl (registered trademark) W-900 ”; softening point 132 ° C .; manufactured by Mitsui Chemicals), Surface treatment composition No. 1-8 were prepared. The blending ratio was a solid content ratio of 85% for the copolymer, 10% for the silica, and 5% for the wax mixture. In the wax mixture, the same amount (50% each) of wax having an average particle diameter of 1 μm and 0.6 μm was used.

0.5 mm thick JIS: 1 type pure titanium plate, JIS: 2 types pure titanium plate, electrogalvanized steel sheet (plating adhesion amount: 20 g / m ^{2 on} each side; EG), hot dip galvanized steel sheet (plating adhesion amount; One side of 60 g / m ² each; GI) was used as the original plate. In the laboratory roll coater, each surface treatment composition No. 1-8 were apply | coated to the front and back, and it dried at the exit side plate | board temperature of 120 degreeC of a hot-air drying furnace, and manufactured the alkali-soluble lubrication metal plate with a film adhesion amount of 1.0 g / m < ² >.

  Table 2 shows the results of the titanium plate. Experiment No. 1 is an example in which only press oil was applied to JIS: Class 1 pure titanium plate. 2 is an example in which only press oil is applied to a JIS: type 2 pure titanium plate. Experiment No. Nos. 3 to 10 are examples using a JIS: type 2 pure titanium plate as an original plate. 3-No. 6 is an example of the present invention, Experiment No. 7 to 10 are comparative examples.

Table 3 shows the results of EG and GI. Experiment No. 11 and 15 are examples using only press oil. Nos. 12 and 16 are examples of press molding after placing a polyethylene sheet (thickness 20 μm; a plastic bag manufactured by Nippon Sanipack Co., Ltd.) on a metal plate during press molding. Experiment No. 13-14 and 17-18 are examples of the present invention, and others are comparative examples.

Experimental example 2
The ratio of 85% copolymer, 10% silica, and 5% wax mixture was not changed, and the ratio of the wax having an average particle diameter of 1 μm and the wax having an average particle diameter of 0.6 μm in the wax mixture was changed as shown in Table 4. Copolymer emulsion No. Each surface treatment composition was applied and dried on a JIS: type 2 pure titanium plate having a plate thickness of 0.5 mm in the same manner as in Experimental Example 1 except that only 1 was used to obtain an alkali-soluble lubricating metal plate. . The evaluation results are shown in Table 4.

Experimental example 3
The amount of addition of the wax mixture (mixture of 50:50 wax having an average particle diameter of 1 μm and a wax having an average particle diameter of 0.6 μm) was changed as shown in Table 5 without changing the silica 10%. In addition, the amount of the copolymer was changed according to the amount of addition of the wax mixture so that the total amount of the copolymer, silica and wax mixture was 100%. Each surface treatment composition was applied and dried on a JIS: type 2 pure titanium plate having a plate thickness of 0.5 mm in the same manner as in Experimental Example 1 except that only 1 was used to obtain an alkali-soluble lubricating metal plate. . The evaluation results are shown in Table 5.

Experimental Example 4
Copolymer emulsion No. No. 1 was used, and the surface treatment composition was prepared without changing the ratio of 85% copolymer, 10% silica, and 5% wax mixture (or a mixture of wax and fluorine-based lubricant). At this time, the wax or the fluorine-based lubricant was used by mixing 50% of a large average particle size and a small one. The types of wax and fluorine-based lubricant are shown below. All Chemipearls are spherical polyethylene waxes.
a: “Chemipearl (registered trademark) W-700” (average particle size 1 μm; softening point 132 ° C .; manufactured by Mitsui Chemicals, Inc.)
b: “Chemipearl (registered trademark) W-900” (average particle size 0.6 μm; softening point 132 ° C .; manufactured by Mitsui Chemicals, Inc.)
c: “Chemipearl (registered trademark) W-300” (average particle size 3 μm; softening point 132 ° C .; manufactured by Mitsui Chemicals, Inc.)
d: “Chemipearl (registered trademark) W-500” (average particle diameter 2.5 μm; softening point 113 ° C .;
(Mitsui Chemicals)
e: “Chemipearl (registered trademark) WF-640” (average particle size 1.0 μm; softening point 113 ° C .; manufactured by Mitsui Chemicals, Inc.)
f: “Chemipearl (registered trademark) W-950” (average particle size 0.6 μm; softening point 113 ° C .; manufactured by Mitsui Chemicals, Inc.)
g: Fluorine-based lubricant “KTL500F” (average particle size 0.49 μm (actual value); melting point 310 ° C .; manufactured by Kitamura Co., Ltd.)
h: Fluorine-based lubricant “PTFE 31-JR” (average particle size 0.2 to 0.25 μm; melting point 327 ° C .; manufactured by Mitsui DuPont Fluorochemical Co., Ltd.)

Further, the coating amount was changed between 0.5 and 2.0 g / m ² as shown in Table 6. Except for these conditions, in the same manner as in Experimental Example 1, each surface treatment composition was applied to a JIS: type 2 pure titanium plate having a plate thickness of 0.5 mm and dried to obtain an alkali-soluble lubricating metal plate. The evaluation results are shown in Table 6.

In addition, the film thickness (μm) in Table 6 is an approximate value obtained by converting the film adhesion amount (g / m ² ) by the following formula. Since 10% of colloidal silica having a specific gravity of 2.2 and 90% of resin and wax having a specific gravity of 1.0 were contained in the film, the following equation was used.

Experimental Example 5
Copolymer emulsion No. No. 1 was used, the wax mixture (50:50 mixture of wax having an average particle diameter of 1 μm and wax having an average particle diameter of 0.6 μm) was changed to 5%, and the types and addition amounts of silica were changed as shown in Table 7. did. In addition, the amount of the copolymer was changed according to the amount of silica added so that the total amount of the copolymer, silica and wax mixture was 100%, and the other conditions were the same as in Experimental Example 1. Each surface treatment composition was applied to a JIS: 2 type pure titanium plate having a plate thickness of 0.5 mm and dried to obtain an alkali-soluble lubricating metal plate. The evaluation results are shown in Table 7.

The colloidal silica used is as follows.
I: “Snowtex (registered trademark) OL” (pH 2 to 4; particle size 40 to 50 nm; manufactured by Nissan Chemical Industries, Ltd.)
II: “Snowtex (registered trademark) O” (pH 2 to 4; particle size 10 to 20 nm; manufactured by Nissan Chemical Industries, Ltd.)
III: “Snowtex (registered trademark) OUP” (pH 2 to 4; particle size 40 to 100 nm;
(Manufactured by Nissan Chemical Industries)
IV: “Snowtex (registered trademark) AK” (pH 4-6; particle size 10-20 nm; manufactured by Nissan Chemical Industries, Ltd.)
V: "Snowtex (registered trademark) 20L" (pH 9.5 to 11.0; particle size 40 to 50 nm; manufactured by Nissan Chemical Industries, Ltd.)

The alkali-soluble lubricating metal plate of the present invention has a lubrication film excellent in press formability and alkali film-removing property. Also, excellent press formability could be imparted. Moreover, since the lubricating film of the present invention is excellent in alkali de-filming property, it can be easily removed by alkali degreasing treatment after press molding and does not hinder the coating property in the subsequent electrodeposition coating. Therefore, the alkali-soluble lubricating metal plate of the present invention is suitable for application in the field where severe forming is performed, and is particularly suitable for the heat exchange part of a plate heat exchanger. In addition, the present invention can be applied to various uses such as home appliances, building materials, and moving medium materials such as ships and automobile parts.

Claims (10)

A metal plate provided with an alkali-soluble lubricating film obtained from a surface treatment composition,
The surface treatment composition includes a structural unit (A-1) derived from an α, β-ethylenically unsaturated carboxylic acid and a structural unit (A-2) derived from an α, β-ethylenically unsaturated carboxylic acid ester. Copolymer (A) synthesized from a monomer component containing, colloidal silica (B) having a particle diameter of 40 to 50 nm, and spherical polyethylene wax having a volume average particle diameter in the range of 0.9 μm to 1.4 μm And a spherical polyethylene wax having a volume average particle diameter in the range of 0.45 μm to 0.8 μm, and has one peak in the range of 0.9 μm to 1.4 μm. multimodal excellent press formability and alkaline coating removal property, characterized in that those comprising a particle size distribution wax mixtures consisting of only wax mixture showing a a (C) there is one peak in the range of 8μm Alkali-soluble lubricant metal plate was.   The wax mixture (C) is a total of a spherical polyethylene wax having a volume average particle size in the range of 0.9 μm to 1.4 μm and a spherical polyethylene wax having a volume average particle size in the range of 0.45 μm to 0.8 μm. 2. The alkali-soluble lubricating metal plate according to claim 1, comprising 100 to 50% by mass of spherical polyethylene wax having a volume average particle diameter in the range of 0.45 μm to 0.8 μm in 100% by mass.   The softening points of spherical polyethylene wax having a volume average particle diameter of 0.9 μm to 1.4 μm and spherical polyethylene wax having a volume average particle diameter of 0.45 μm to 0.8 μm are both 113 to 132 ° C. The alkali-soluble lubricating metal plate according to claim 1 or 2.   Both the static friction coefficient and the dynamic friction coefficient on the surface of the alkali-soluble lubricating film are 0.15 or less, and the value when the dynamic friction coefficient is subtracted from the static friction coefficient is -0.02 to +0.02. The alkali-soluble lubricating metal plate according to any one of claims 1 to 3.   When the total amount of the copolymer (A), the colloidal silica (B) and the wax mixture (C) is 100% by mass, the surface treatment composition is 70 to 90% by mass of the copolymer (A), colloidal The alkali-soluble lubricating metal plate according to any one of claims 1 to 4, comprising 5 to 20% by mass of silica (B) and 3.5 to 10% by mass of the wax mixture (C).   The structural unit (A-1) derived from the α, β-ethylenically unsaturated carboxylic acid of the copolymer (A) is a structural unit derived from methacrylic acid, and the α, β-ethylenically unsaturated carboxylic acid Derived from α, β-ethylenically unsaturated carboxylic acid in a total of 100% by mass of derived structural unit (A-1) and structural unit (A-2) derived from α, β-ethylenically unsaturated carboxylic acid ester The alkali-soluble lubricating metal plate according to claim 1, wherein the constituent unit (A-1) is 20 to 40% by mass.   The alkali-soluble lubricating metal plate according to any one of claims 1 to 6, wherein the copolymer (A) has an acid value of 150 mgKOH / g or more. Alkali-soluble lubricating metal sheet according to any one of claims 1 to 7 attached amount of the alkali-soluble lubricating film is 0.6~1.5g / m ^2.   A method for producing an alkali-soluble lubricating metal plate according to any one of claims 1 to 8, wherein the surface treatment composition according to claim 1 is applied to the metal plate, and then the plate temperature is 100 to 130. A method for producing an alkali-soluble lubricating metal plate excellent in press formability and alkali film-removing property, characterized by drying at ° C.   The method for producing an alkali-soluble lubricating metal plate according to claim 9, wherein the metal plate is a pure titanium plate or a titanium alloy plate.