JP7193246B2 - Resin-laminated metal sheet and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin-laminated metal sheet and a method for manufacturing the same.

For example, as disclosed in Patent Documents 1 to 6, a resin-laminated metal plate having polymer brushes formed on the surface of the metal plate is known as a technique for improving the surface properties of the metal plate. In this technology, by covalently bonding a polymer brush resin layer to the surface of a metal plate with a high density of polymer chain units, the molecular functions of the bonded resin (polymer chains) can be maintained over a long period of time on the metal plate. It can be applied to the surface. Specifically, a resin layer is formed in which a hydrophilic or hydrophobic resin is covalently bonded to a metal plate at molecular level intervals. As a result, it is expected that self-cleaning function, lubricating function (sliding function) applying low frictional resistance, and adhesive function using strong attractive force between polymer chains will be expressed on the surface of the metal plate at a high level. .

Japanese Patent Application Laid-Open No. 2002-020894 Japanese Patent Publication No. 2004-538132 JP 2017-042415 A JP 2016-138260 A JP 2008-246992 A Japanese Patent Application Laid-Open No. 2006-307110

By the way, the resin layer is composed of a hydrophobic resin or a hydrophilic resin. When the resin layer is composed of a hydrophobic resin, the resin layer repels dirt (particularly oily dirt; the same shall apply hereinafter), thereby exerting a self-cleaning function. On the other hand, when the polymer brush is composed of a hydrophilic resin, the resin layer retains (traps) a large amount of water as water enters between the hydrophilic resin (polymer chains). As a result, the hydrophilic resin forming the resin layer rises substantially perpendicularly to the surface of the metal plate, and the contact angle with water becomes small. This realizes a high self-cleaning function. Specifically, dirt adhering to the surface of the resin layer is easily replaced with water. Therefore, dirt can be removed only with water. By forming the resin layer with a hydrophilic resin, it is often possible to exhibit a higher self-cleaning function. For this reason, a polymer brush made of a hydrophilic resin has received particular attention.

However, in the conventional technology, the hydrophilic resin is directly covalently bonded to the metal plate. Therefore, moisture contained in the resin layer directly contacts the metal surface. Therefore, when the metal plate is used for a long period of time, this moisture may corrode the surface of the metal plate. As a result, there are cases where the surface of the metal plate is destroyed and the function cannot be maintained for a long period of time.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved resin-laminated metal sheet capable of maintaining surface functions for a longer period of time. Another object of the present invention is to provide a resin-laminated metal sheet and a method for manufacturing the same.

In order to solve the above problems, according to one aspect of the present invention, a metal plate, and a hydrophobic resin film having a thickness of 1 μm to 2 mm and containing a hydrophobic resin as a matrix or continuous phase formed on the surface of the metal plate. and a hydrophilic resin layer formed on the surface of the hydrophobic resin film and containing a hydrophilic resin covalently bonded to the surface of the hydrophobic resin film.

Here, the density of the hydrophilic resin may be 0.01 strands/nm ² or more.

Hydrophilic resins may also include dipolar ion-containing resins.

Moreover, the hydrophobic resin film may contain a thermoplastic resin as the hydrophobic resin.

Further, the hydrophobic resin film may contain, as a thermoplastic resin, any one or more selected from the group consisting of polyester resin, polyvinyl chloride resin, polyolefin resin, fluororesin, and acrylic resin.

Moreover, the hydrophobic resin film may contain a thermosetting resin as the hydrophobic resin.

According to another aspect of the present invention, there is provided a method of manufacturing a resin-laminated metal sheet for manufacturing the above-described resin-laminated metal sheet, comprising the steps of forming a hydrophobic resin film, and applying light polymerization to the surface of the hydrophobic resin film. A step of forming a hydrophilic resin layer on a hydrophobic resin film by covalently bonding a hydrophilic resin by a method or a living radical polymerization method; A method for manufacturing a resin-laminated metal sheet is provided, comprising a step of laminating.

According to another aspect of the present invention, there is provided a resin-laminated metal sheet manufacturing method for manufacturing the resin-laminated metal sheet described above, comprising the steps of: laminating a hydrophobic resin film on a metal plate; and forming a hydrophilic resin layer on the hydrophobic resin film by covalently bonding the hydrophilic resin by a photopolymerization method. be.

As described above, according to the present invention, it is possible to maintain the surface function of the resin-laminated metal sheet for a longer period of time.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows schematic structure of the resin laminated metal plate which concerns on embodiment of this invention.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Overall configuration of resin laminated metal plate>
First, based on FIG. 1, the overall configuration of a resin-laminated metal sheet 1 according to this embodiment will be described. The resin-laminated metal plate 1 includes a metal plate 10 , a hydrophobic resin film 20 and a hydrophilic resin layer 30 . In other words, the hydrophobic resin film 20 is formed between the metal plate 10 and the hydrophilic resin layer 30 in this embodiment. The hydrophilic resin layer 30 is a layer that constitutes a polymer brush. Each configuration will be described in detail below.

(1-1. Configuration of metal plate)
The type of metal plate 10 is not particularly limited, and widely known metal plates can be used. Examples of the metal plate 10 include a steel plate, a stainless steel plate, an Al plate, a Cu plate, a brass plate, a Ti plate, a chrome plate, a nickel plate, a zinc plate, and a magnesium plate. Examples of steel sheets include tin plate, thin tin plated steel plate, electrolytic chromic acid treated steel plate (tin-free steel plate), steel plate for cans such as nickel plated steel plate, hot-dip galvanized steel plate, hot-dip zinc-iron alloy plated steel plate, Hot-dip zinc-aluminum-magnesium alloy plated steel plate, hot-dip aluminum-silicon alloy plated steel plate, hot-dip lead-tin alloy plated steel plate, etc. , electroplated steel sheets such as electrolytic zinc-chromium alloy plated steel sheets, cold-rolled steel sheets, and the like. The steel sheet may be coated on either one side or both sides. The steel plate may or may not be chromate-treated. However, for the purpose of preventing corrosion on the surface of the metal plate 10 and prolonging its life, it is possible that a known chromium or non-chromium rust prevention treatment (chemical conversion treatment) such as zirconia, titanium, or vanadium is applied. preferable.

(1-2. Configuration of Hydrophobic Resin Film)
A hydrophobic resin film 20 is formed on the surface of the metal plate 10 . The hydrophobic resin film 20 is a film containing a hydrophobic resin as a matrix or continuous phase. In the present embodiment, since the hydrophobic resin film 20 is interposed between the hydrophilic resin layer 30 and the metal plate 10 , even if the hydrophilic resin layer 30 retains a large amount of water, the water is absorbed by the metal plate 10 . Direct contact can be suppressed. Therefore, even if the resin-laminated metal plate 1 is used for a long period of time, the metal plate 10 is less likely to corrode.

Here, the hydrophobic resin means a resin having a water absorption rate of 5% or less when left in the air at 23° C. for 24 hours. Here, the water absorption is obtained by dividing the amount of change in mass after the resin to be measured is left under the above conditions by the mass of the resin before standing. In other words, the water absorption is the weight percent of water absorbed by the resin. When a resin film containing a resin having a water absorption rate of more than 5% as a matrix or a continuous phase is formed on the surface of the metal plate 10, the resin film has a weak barrier property against moisture. Therefore, when the resin-laminated metal plate is used for a long time, the surface of the metal plate 10 may corrode.

Examples of hydrophobic resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyester resins, polyvinyl chloride (PVC) resins, polyolefin resins, fluororesins, acrylic resins, polyamide resins, and polycarbonate resins. Examples of polyester resins include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). Examples of fluororesins include polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and the like. Examples of acrylic resins include polymethyl methacrylate (PMMA).

Examples of thermosetting resins include urethane resins, polyimide resins, silicone resins, and melamine resins. Urethane resins include, for example, polyurethane resins and acrylic urethane resins. Examples of melamine resins include, for example, polyester melamine resins. Examples of silicone resins include acrylic silicone resins and silicone rubbers.

The hydrophobic resin film 20 may be composed of one of the above-listed resins, or may be composed of a plurality of resins. Among the resins listed above, polyester resins, polyvinyl chloride resins, polyolefin resins, fluororesins, and acrylic resins are selected from the viewpoint of moisture barrier properties, adhesion to the metal plate 10, and workability of the resin-laminated metal plate 1. , urethane resins, silicone resins, and melamine resins are preferred.

The thickness of the hydrophobic resin film 20 should be 1 μm to 2 mm. If the thickness is less than 1 μm, the hydrophilic resin layer 30 has insufficient barrier properties against moisture adsorbed thereon. As a result, the surface of the metal plate 10 may corrode due to moisture. On the other hand, if the thickness is more than 2 mm, stress remains in the hydrophobic resin film 20 when the hydrophobic resin film 20 is laminated on the metal plate 10, and the hydrophobic resin film 20 is exposed during use of the resin-laminated metal plate 1. 20 may peel off from the metal plate 10 . Furthermore, when the resin-laminated metal plate 1 is processed, there is a case where the resin-laminated metal plate 1 is poorly processed due to strain caused by the springback of the hydrophobic resin film 20 .

The thickness of the hydrophobic resin film 20 is preferably 2 μm to 1 mm for the purpose of ensuring barrier properties against moisture and adhesion to the metal plate 10 . Furthermore, considering the operability when laminating the hydrophobic resin film 20 on the metal plate 10, the thickness is more preferably 4 μm or more, and from the viewpoint of reducing distortion during processing, the thickness is 400 μm or less. is more preferable.

Moreover, it is desirable that the hydrophobic resin film 20 is firmly adhered to the surface of the metal plate 10 . Specifically, when the hydrophobic resin film 20 itself is thick and strong enough to measure the peel strength, the peel strength of the hydrophobic resin film 20 laminated on the metal plate 10 is 10 N/25 mm or more. preferable. If the peel strength cannot be measured, the hydrophobic resin film 20 laminated on the metal plate 10 is cross-cut to a size of 10×10 mm, and then the cross-cut portion is peeled off with a tape. At this time, it is desirable that 80% or more of the cross-cut portions have adhesion strength of at least the level at which the tape does not peel off. If the above conditions are not satisfied, the hydrophobic resin film 20 may peel off from the metal plate 10 when the resin-laminated metal plate 1 is washed with a brush or the like for a long period of time, and the target durability may not be achieved.

The method for laminating the hydrophobic resin film 20 on the metal plate 10 is not particularly limited, and the hydrophobic resin film 20 may be laminated on the metal plate 10 by a known lamination method. For example, the hydrophobic resin film 20 is prepared in advance (that is, the hydrophobic resin is formed into a film), and this hydrophobic resin film 20 is laminated on the metal plate 10 (that is, laminated). good. At this time, the hydrophobic resin film 20 may be laminated on the metal plate 10 using an adhesive, or the hydrophobic resin film 20 may be laminated on the metal plate 10 by thermal fusion without using an adhesive. You may This method is suitable when the hydrophobic resin film 20 has self-holding properties, for example, when the hydrophobic resin is a thermoplastic resin. The hydrophobic resin film 20 may be laminated on the metal plate 10 after the hydrophilic resin layer 30, which will be described later, is formed on the hydrophobic resin film 20, or the hydrophobic resin film 20 may be laminated on the metal plate 10. A hydrophilic resin layer 30 may be formed on the hydrophobic resin film 20 after lamination.

In addition, the hydrophobic resin is made into a paint by a process such as dissolving the hydrophobic resin in a solvent or in a molten state, and the paint is applied onto the metal plate 10 by a coating method such as dip coating, roll coating, bar coating, or curtain coating. may be laminated to In this case, the hydrophilic resin layer 30 is formed on the hydrophobic resin film 20 formed on the metal plate 10 . This method is suitable when the hydrophobic resin film 20 does not have self-holding properties, for example, when the hydrophobic resin is a thermosetting resin. Alternatively, a powdered hydrophobic resin may be applied onto the metal plate 10 by baking. In this case, the hydrophilic resin layer 30 is formed on the hydrophobic resin film 20 formed on the metal plate 10 .

From the viewpoint that the hydrophobic resin film 20 and the surface of the metal plate 10 are brought into close contact with each other under the above preferable conditions with good production efficiency, a method of laminating the hydrophobic resin film 20 on the metal plate 10 by lamination, roll or curtain coating is preferable. In any case, it is preferable to activate the resin surface by a known method such as corona treatment, plasma, surface edging, etc., if necessary. Moreover, it is preferable to use an adhesive having affinity with the hydrophobic resin film 20 and the metal plate 10 . Furthermore, it is desirable that the surface of the metal plate 10 is also subjected to a known chemical conversion treatment for activation such as chromate treatment or phosphoric acid treatment.

(1-3. Configuration of hydrophilic resin layer)
The hydrophilic resin layer 30 is formed on the hydrophobic resin film 20 and covalently bonded to the surface of the hydrophobic resin film 20 (more specifically, the hydrophobic resin forming the surface of the hydrophobic resin film 20). containing volatile resins. Since the hydrophilic resin constituting the hydrophilic resin layer 30 is covalently bonded to the hydrophobic resin in this manner, the hydrophilic resin layer 30 functions as a so-called polymer brush. As a result, resin-laminated metal sheet 1 can exhibit excellent self-cleaning function, lubricating function (sliding function), adhesive function, etc. on the surface of resin-laminated metal plate 1 at a high level. In other words, the hydrophilic resin layer 30 retains a large amount of water, thereby reducing the contact angle with water. As a result, a high self-cleaning function and lubrication performance (water lubrication performance) are realized. Furthermore, the hydrophilic resin layer 30 exhibits a high adhesion function.

Here, the hydrophilic resin means a resin having a water absorption of more than 5% when left in the air at 23° C. for 24 hours. Alternatively, the hydrophilic resin may be a water-soluble resin. A water-soluble resin refers to a resin having a solubility of 0.1 g or more in 100 g of water at 25° C. and 1 bar. When the resin layer is formed on the hydrophobic resin film 20 by using a resin having a water absorption rate of 5% or less or a non-water-soluble resin, the interfacial tension between water and the resin layer is large (that is, the contact angle with water is large), and dirt (particularly oily dirt) adhering to the surface of the resin layer cannot be sufficiently replaced with water. Therefore, the self-cleaning function cannot be exhibited. Furthermore, the water cannot be sufficiently adsorbed, and the water lubrication function cannot be exhibited.

Specifically, the hydrophilic resin is a resin containing a hydrophilic monomer as a main component (for example, 50 mol % or more of all monomers constituting the hydrophilic resin are hydrophilic monomers). Specific examples of the hydrophilic resin are described below. Of course, the hydrophilic resin is not limited to these specific examples, and any resin that satisfies the above conditions (water absorption exceeds 5% when left in the atmosphere at 23 ° C. for 24 hours). may be

A hydrophilic monomer is, for example, a hydrophilic substituent-containing monomer having a hydrophilic functional group or a functional group convertible to a hydrophilic functional group. Hydrophilic substituent-containing monomers include, for example, amide groups, sulfate groups, sulfonic acid groups, carboxylic acid groups, hydroxyl groups, amino groups, amide groups, oxyethylene groups, functional groups that are precursors thereof, and the like. It is a monomer having a hydrophilic group.

In addition to the above, hydrophilic monomers include alkali metal-containing monomers (monomers containing an alkali metal in the molecule), zwitterionic monomers (zwitterionic group-containing compounds: compounds having a permanent positive charge center and a negative charge center). etc. The hydrophilic monomers listed above may be used alone or in combination of two or more.

Specific examples of hydrophilic substituent-containing monomers include (meth) acrylic acid, (meth) acrylic acid esters (methoxyethyl (meth) acrylate, alkoxyalkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate, hydroxy Examples include hydroxyalkyl (meth)acrylates such as ethyl (meth)acrylate), acrylonitrile, and monomers having a C—N bond in the molecule. Monomers having a CN bond in the molecule include (meth)acrylamide; N-alkyl-substituted (meth)acrylamide derivatives (N-ethyl (meth)acrylamide, Nn-propyl (meth)acrylamide, N-isopropyl ( alkoxyalkyl (meth)acrylamides such as meth)acrylamide, N-cyclopropyl (meth)acrylamide; N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-ethoxyethyl (meth)acrylamide; N , N-dialkyl-substituted (meth)acrylamide derivatives (N,N-dimethyl(meth)acrylamide, N,N-ethylmethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, etc.); hydroxy(meth)acrylamide; Hydroxy(meth)acrylamide derivatives (hydroxyalkyl(meth)acrylamides such as N-hydroxyethyl(meth)acrylamide); (meth)acrylamide derivatives having a cyclic group ((meth)acryloylmorpholine, etc.);

Specific examples of alkali metal-containing monomers include alkali metal acrylate salts (sodium acrylate, potassium acrylate, etc.); alkali metal methacrylate salts (sodium methacrylate, potassium methacrylate, etc.), (meth)acrylic acid amine salts; Alkali metal salts of itaconate (sodium itaconate, potassium itaconate, etc.); alkali metal 3-vinylpropionates (sodium 3-vinylpropionate, potassium 3-vinylpropionate, etc.); alkali metal vinylsulfonates (vinylsulfone) sodium phosphate, potassium vinylsulfonate, etc.); 2-sulfoethyl (meth) acrylic acid alkali metal salts (sodium 2-sulfoethyl (meth) acrylate, 2-sulfoethyl (meth) potassium acrylate, etc.); 3-sulfopropyl (meth) ) acrylic acid alkali metal salts (sodium 3-sulfopropyl (meth) acrylate, 3-sulfopropyl (meth) potassium acrylate, etc.); 2-acrylamido-2-methylpropanesulfonic acid alkali metal salts (2-acrylamide-2 -sodium methylpropanesulfonate, potassium 2-acrylamido-2-methylpropanesulfonate, etc.); alkali metal styrenesulfonate (sodium styrenesulfonate, potassium styrenesulfonate, etc.);

Specific examples of zwitterionic monomers include quaternary ammonium cations, N-alkylimidazole cations, N-alkylpyridinium cations and the like as positively charged residues, sulfate anions, phosphate anions, borate anions, carboxylates and the like as negatively charged residues. Acrylic acid ester-based monomers, methacrylic acid ester-based monomers, styryl-based monomers, (meth)acrylamide-based monomers, etc., which are contained as charge-bearing residues, can be mentioned. More specifically, 2-methacryloxyethylphosphorylcholine, a methacrylic acid ester monomer consisting of a salt of a quaternary ammonium cation and a phosphate anion, and a methacrylic acid ester monomer consisting of a salt of a quaternary ammonium cation and a sulfate anion. 3-(N-[2-methacryloyloxyethyl]-N,N-dimethylammonio)propanesulfonate, (3-(methacryloylamino)propyl) of a methacrylamide-based monomer consisting of a salt of a quaternary ammonium cation and a sulfate anion dimethyl-3-sulfopropyl)ammonium salt, 1-(3-sulfopropyl)-2-vinylpyridinium hydroxide consisting of a salt of a quaternary pyridinium cation and a sulfate anion, and the like. Also included are 2-(methacryloyloxy)ethyltrimethylammonium chloride, 2-methacryloyloxyethylphosphorylcholine, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)aminium hydroxide and the like.

Among the hydrophilic substituent-containing monomers and alkali metal-containing monomers listed above, (meth)acrylic acid, (meth)acrylic acid esters, and alkali (meth)acrylates are used from the viewpoint of obtaining excellent slidability and durability. Metal salts, (meth)acrylic acid amine salts, acrylonitrile, (meth)acrylamide, dimethyl (meth)acrylamide, diethyl (meth)acrylamide, isopropyl (meth)acrylamide, hydroxyethyl (meth)acrylamide, methoxyethyl (meth)acrylamide, Methoxymethyl (meth)acrylamide, (meth)acryloylmorpholine, 3-sulfopropyl methacrylic acid potassium salt are preferred. Further, (meth)acryloylmorpholine, methoxymethyl(meth)acrylamide, (meth)acrylamide and 2-methoxyethyl acrylate are more preferable, and methoxymethyl(meth)acrylamide and 2-methoxyethyl acrylate are particularly preferable.

Among zwitterionic monomers, 2-(methacryloyloxy)ethyltrimethylammonium chloride, 2-methacryloyloxyethylphosphorylcholine and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) are preferred from the viewpoint of affinity with water. ) aminium hydroxide is preferred. When the resin-laminated metal sheet 1 is used as a medical material or the like, 2-methacryloxyethylphosphorylcholine is preferable as the dipolar ionic monomer because of its excellent compatibility with living tissue.

Of the hydrophilic monomers listed above, the zwitterionic monomers are most preferred. Hydrophilic resins containing zwitterionic monomers, ie, zwitterion-containing resins, have a very high affinity for moisture. The hydrophilic resin that constitutes the hydrophilic resin layer 30 is not limited to these examples, and the water absorption rate when left in the atmosphere at 23 ° C. for 24 hours is more than 5%, or if it is a water-soluble resin. Just do it.

The length of the polymer chain of the hydrophilic resin is preferably 10-50000 nm, more preferably 100-50000 nm. Within this range, the longer the polymer chain, the better self-cleaning, sliding, and adhesive functions can be exhibited. Conversely, when the polymer chain length is less than 10 nm, these functions tend to be difficult to obtain. If the polymer chain length exceeds 50000 nm, further improvement of these functions cannot be expected. Furthermore, raw material costs tend to rise due to the need for expensive monomers. Furthermore, the surface pattern due to the surface treatment (that is, the formation of the hydrophilic resin layer 30) becomes visible to the naked eye, which tends to impair the appearance of the resin-laminated metal plate 1.

Here, the length of the polymer chain can be converted from the number average molecular weight of the hydrophilic resin and the size of the monomer unit. Here, it may be estimated that the monomer units are arranged in a straight line. A number average molecular weight is measured, for example by the following method. That is, the hydrophilic resin homogenate (hydrophilic resin not covalently bonded to the hydrophobic resin) that is by-produced when the hydrophilic resin layer 30 is covalently bonded to the hydrophobic resin is recovered. These by-products often have the same molecular weight as the hydrophilic resin covalently bonded to the hydrophobic resin. Number average molecular weight can be measured.

The thickness of the hydrophilic resin layer 30 is not particularly limited, but a thickness of about several tens of nanometers can sufficiently exhibit the function of the hydrophilic resin.

The density of the hydrophilic resin in the hydrophilic resin layer 30 is preferably 0.01 strands/nm ² or more. Here, the density of the hydrophilic resin means the number of hydrophilic resins bonded per unit area (nm ² ) of the surface of the hydrophobic resin film 20, and is synonymous with "graft density". The density (=graft density) of the hydrophilic resin is preferably 0.01 strands/nm ² or more, more preferably 0.02 strands/nm ² or more.

By setting the density of the hydrophilic resin to 0.01 chains/nm ² or more, an osmotic pressure is generated when the hydrophilic resin layer 30 absorbs water, and the polymer chains of the hydrophilic resin form a hydrophobic resin film. 20 extends vertically from the surface. As a result, the polymer chains have less self-entropy and less molecular motion. This improves sliding, adhesion and self-cleaning functions. This effect becomes more pronounced as the density of the hydrophilic resin increases, but when the density is 0.05 lines/nm ² or more, the above effect tends to be substantially constant. On the other hand, the density of the hydrophilic resin is preferably 0.15 strands/nm ² or less, more preferably 0.1 strands/nm ² or less, and even more preferably 0.05 strands/nm ² or less. If the density of the hydrophilic resin becomes too high, it becomes difficult for each hydrophilic resin to stretch vertically due to the excluded volume effect of the hydrophilic resin polymer chains. Furthermore, in the process (described later) of growing the hydrophilic resin on the hydrophobic resin film 20, the polymer chains of the hydrophilic resin may not grow sufficiently long. On the other hand, when the density is less than 0.01 chains/nm ² , the osmotic pressure when the hydrophilic resin layer 30 absorbs moisture is small, and the molecular motion of the hydrophilic resin chains increases. As a result, the sliding, adhesion, and self-cleaning functions may not be sufficient.

The density of the hydrophilic resin (main chain/nm ² , s) is obtained by determining the total mass (graft amount, w) of the highly hydrophilic resin formed by extending from the surface of the hydrophobic resin film by elemental analysis, etc. Using the value, the surface area (S, nm ² ) of the hydrophobic resin film 20, the number average molecular weight (Mn) of the hydrophilic resin, and Avogadro's number (Av), it is calculated from the following Equation 1.
s=(w/Mn)Av/S (Formula 1)

As a method of covalently bonding the hydrophilic resin to the hydrophobic resin starting from the surface of the hydrophobic resin film 20, the surface of the hydrophobic resin film 20 (more specifically, the surface of the hydrophobic resin film 20 is Hydrophobic resin) is graft-polymerized with a hydrophilic resin monomer (for example, the hydrophilic monomer described above) to grow a polymer chain of the hydrophilic resin (so-called Graft-from method); There is a method (so-called Graft-to method) in which a hydrophilic resin having a functional group that reacts with the surface functional group is chemically bonded (covalently bonded) to the hydrophobic resin.

The outline of the Graft-from method is as follows. First, after the polymerization initiator is covalently bonded to the surface of the hydrophobic resin film 20, the polymerization initiator on the surface of the hydrophobic resin film 20 is activated by plasma irradiation, light irradiation, heating, or the like. and. Using this active species as a starting point, the monomer of the hydrophilic resin arranged so as to be in contact with the surface of the hydrophobic resin film 20 is polymerized. According to this method, the ends of the polymer chains of the produced hydrophilic resin are covalently bonded to the surface of the hydrophobic resin film 20 .

The graft-from method includes a photopolymerization method (photograft polymerization method), a living radical polymerization method, a plasma irradiation graft polymerization method, a radiation irradiation graft polymerization method, and the like. Here, the outline of the living radical polymerization method is as follows. That is, a free radical polymerization initiator, a photopolymerization initiator, and a primitive transfer radical polymerization initiator are covalently bonded to the surface of the hydrophobic resin film 20 . Then, by treating the surface of the hydrophobic resin film 20 with plasma or electron beams, radicals, which are active species, are generated on the surface. Then, the surface of the hydrophobic resin film 20 having the active species and the monomer of the hydrophilic resin are polymerized. A graft polymer chain of the hydrophilic resin can be grown by reacting a compound having a polymerizable double bond (for example, the hydrophilic monomer described above).

In the case of the photopolymerization method, after applying a polymerization initiator to the surface of the hydrophobic resin film 20 , a hydrophilic resin monomer is arranged on the surface of the hydrophobic resin film 20 . By irradiating the surface of the hydrophobic resin film 20 with light, the polymerization initiator and the surface of the hydrophobic resin film 20 can be covalently polymerized, and then the monomers of the hydrophilic resin can be sequentially polymerized.

The Graft-from method is also described in the following known documents, and these methods can be used without particular limitation in the present embodiment. For example, Shin Kobunshi Jikkengaku 10, Kobunshi Gakkai ed., 1994, published by Kyoritsu Shuppan Co., Ltd., page 135, describes photo-graft polymerization and plasma irradiation graft polymerization as surface graft polymerization methods. Adsorption Technique Handbook, NTS Co., Ltd., supervised by Takeuchi, published in February 1999, p. JP-A-63-92658, JP-A-10-296895 and JP-A-11-119413 describe specific methods of photo-graft polymerization. The literature mentioned above, and Y.S. Ikada et al, Macromolecules vol. 19, page 1804 (1986), etc., a plasma irradiation graft polymerization method and a radiation irradiation graft polymerization method are described.

Among the above-mentioned Graft-from methods, the photopolymerization method or the living radical polymerization method is preferable because of the ease of handling of the polymerization operation, the reaction rate, and the control of the molecular weight.

Therefore, a specific example of the photopolymerization method will be described below. Of course, the photopolymerization method applicable to this embodiment is not limited to this. First, a photoactive polymerization initiator such as a radical polymerization initiator, an anionic polymerization initiator, or a cationic polymerization initiator is applied to the surface of the hydrophobic resin film 20 . Examples of photoinitiators include acetophenones such as p-tert-butyltrichloroacetophenone, 2,2'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4, ketones such as 4'-bisdimethylaminobenzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone and 2-isopropylthioxanthone; benzoin ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether and benzoin isobutyl ether and benzyl ketals such as benzyl dimethyl ketal and hydroxycyclohexylphenyl ketone. The photopolymerization initiator can be used in a state of being dissolved or dispersed in the hydrophobic resin, but it is preferably dissolved. Benzophenone compounds such as benzophenone, xanthone, and 9-fluorenone are most preferred from the viewpoint of solubility in hydrophobic resins and versatility.

Next, among the hydrophilic substituent-containing monomers, alkali metal-containing monomers, and zwitterionic monomers exemplified above, a hydrophilic monomer containing a double bond such as a vinyl monomer is applied to the surface of the hydrophobic resin film 20. . By irradiating the surface of the hydrophobic resin film 20 with ultraviolet light of 300 to 400 nm, the hydrophilic monomer is polymerized. Here, a high-pressure mercury lamp, a metal halide lamp, an LED lamp, or the like can be used as the light source. More specific light sources that can be used include a high-pressure mercury lamp, an LED with a central wavelength of 365 nm, and an LED with a central wavelength of 375 nm. As the light source, a light source capable of emitting LED light of 355 to 380 nm is more preferable. In particular, an LED having a center wavelength of 365 nm, which is close to the excitation wavelength of 366 nm of benzophenone, is preferable in terms of efficiency. If the wavelength of the light source is less than 300 nm, the molecule of the object to be modified (that is, the polymerization initiator) may be cut and damaged. For this reason, the light emitted from the light source is preferably light of 300 nm or more, and more preferably light of 355 nm or more from the viewpoint of causing very little damage to the object to be modified. On the other hand, with light exceeding 400 nm, the photopolymerization initiator is less likely to be activated and the polymerization reaction is less likely to proceed.

Next, a specific example of the living radical polymerization method will be described. Of course, the living radical polymerization method applicable to this embodiment is not limited to this. First, a radical polymerization initiator is covalently bonded to the surface of the hydrophobic resin film 20 . The surface of the hydrophobic resin film 20 is coated with the above vinyl monomer and, if necessary, a transition metal catalyst complex such as ruthenium or copper. Then, a vinyl monomer is subjected to living radical polymerization to form a hydrophilic resin layer 30 on the surface of the hydrophobic resin film 20 .

Here, a known method can be selected as the living radical polymerization method, and a nitroxide-mediated living radical polymerization method, an atom transfer radical polymerization method, a reversible addition/elimination chain transfer polymerization reaction (RAFT) method, and the like can be used. Depending on the polymerization method, hydroxylamine derivatives, organic halogen compounds such as α-chloroketone, thiocarbonyl compounds such as trithiocarbonate and dithioester, and the like can be selected as initiators. These initiators are modified so that they can be covalently bonded to the surface of the hydrophobic resin film 20 by introducing a functional group into the initiator according to the type of the hydrophobic resin. Moreover, if necessary, a functional group capable of covalently bonding with the functional group may be introduced to the surface of the hydrophobic resin film 20 as well.

A living radical polymerization method using an atom transfer radical is preferred because the radical polymerization initiator is easily modified. A more specific example of the living radical polymerization method using the atom transfer radical polymerization method is to acid bromide α-chloroketone such as α-bromoisobutyryl bromide and esterify it with hydroxyalkene. Further, this product is hydrosilylated (oxysilanized) with a silane compound to prepare a hydrosilylated atom transfer radical polymerization initiator. On the other hand, the surface of the hydrophobic resin film 20 is also cyanolized with a silane coupling agent or the like. Then, a hydrosilylated atom transfer radical polymerization initiator is applied to the surface of the hydrophobic resin film 20 to covalently bond the atom transfer radical polymerization initiator to the surface of the hydrophobic resin film 20 . After that, the above vinyl monomer is applied to the surface of the hydrophobic resin film 20 and subjected to living radical polymerization.

In both the photopolymerization method and the living radical polymerization method, the polymerization temperature, pressure and the like can be appropriately selected depending on the polymerization initiator and the type of the monomer to be polymerized. Further, after the polymerization, a hydrophilic resin homogenate that is not covalently bonded to the surface of the hydrophobic resin film 20 is produced as a by-product. Therefore, it is preferable to wash the surface of the hydrophobic resin film 20 with a solvent such as water or methanol, which is a good solvent for hydrophilic resins and a poor solvent for hydrophobic resins, to remove the hydrophilic resin homogenate.

Of the photopolymerization method and the living radical polymerization method, the photopolymerization method, which is less affected by a trace amount of ions melted from the metal plate 10 during polymerization, has milder reaction conditions, and has a higher reaction rate, is preferable. In the living radical polymerization method, if the hydrophilic resin layer 30 is grafted after the hydrophobic resin film 20 is laminated on the metal plate 10, the metal ions may be eluted from the metal plate 10 and the polymerization may be difficult to proceed.

A specific example of the Graft-to method is as follows. That is, by preparing a hydrophilic resin having a functional group that reacts with the hydrophobic resin at the end of the main chain or side chain, and chemically reacting this functional group with the functional group on the surface of the hydrophobic resin film 20, hydrophilicity can be obtained. A resin layer 30 is formed on the hydrophobic resin film 20 . The functional group that reacts with the hydrophobic resin is not particularly limited as long as it can react with the functional group on the surface of the hydrophobic resin film 20. Examples include silane coupling groups such as alkoxysilane, isocyanate groups, Examples include amino group, hydroxyl group, carboxyl group, sulfonic acid group, phosphoric acid group, epoxy group, allyl group, methacryloyl group, acryloyl group and the like.

Particularly useful hydrophilic resins having a functional group that reacts with a hydrophobic resin at the end or side chain of the main chain are those having a unit having a trialkoxysilyl group, an amino group, a carboxyl group, an epoxy group, or an isocyanate at the end or side chain. It is a hydrophilic resin.

Comparing the Graft-from method and the Graft-to method, in the Graft-to method, the polymer chains of the hydrophilic resin with increased bulk are successively covalently bonded to the surface of the hydrophobic resin film 20 to form the hydrophobic resin film. Cover 20 surfaces. The surface of the hydrophobic resin film 20 covered with such bulky polymer chains cannot further covalently bond the bulky polymer chains due to the excluded volume effect. As a result, the graft density tends to be sparse. On the other hand, in the Graft-from method, since polymerization starts from the surface of the hydrophobic resin film 20, the excluded volume effect does not occur at the initial stage of polymerization. As a result, the hydrophilic resin corresponding to the density of the base points can be covalently bonded to the surface of the hydrophobic resin film 20 . As a result, if the base points can be fixed to the surface of the hydrophobic resin film 20 at high density, the hydrophilic resin can be covalently bonded to the surface of the hydrophobic resin film 20 at high density. Therefore, the Graft-from method is preferred over the Graft-to method.

Covalent bonding of the hydrophilic resin to the surface of the hydrophobic resin film 20 can be confirmed by, for example, the following method. That is, after the hydrophilic resin is covalently bonded to the surface of the hydrophobic resin film 20, the surface of the hydrophobic resin film 20 is sufficiently coated with a solvent that is a good solvent for the hydrophilic resin and a poor solvent for the hydrophobic resin. wash. As a result, the hydrophilic resin homo-body that is not covalently bonded to the hydrophobic resin film 20 is removed. After that, by analyzing the elements in the hydrophilic resin layer 30 or the mass ratio of the elements by elemental analysis or the like, it can be confirmed that the hydrophilic resin is covalently bonded to the hydrophobic resin film 20 .

As described above, according to the present embodiment, by forming the hydrophilic resin layer 30 on the surface of the hydrophobic resin film 20, dirt (especially oily dirt) adhering to the surface of the metal plate 10 can be removed only with water. A self-cleaning function can be expressed. Furthermore, since the hydrophilic resin layer 30 retains a large amount of water, it can exhibit a high level of water lubrication. Furthermore, the hydrophilic resin layers 30 can be used as a binder to strongly bond the resin-laminated metal sheets 1 to each other. That is, a high adhesion function can also be expressed. In addition, since the hydrophilic resin constituting the hydrophilic resin layer 30 is covalently bonded to the hydrophobic resin film 20, even if the surface of the resin-laminated metal plate 1 is washed with a brush or the like, the hydrophilic resin layer 30 remains intact. These functions can be expressed for a long time without exfoliation. A hydrophobic resin film 20 exists between the surface of the metal plate 10 and the hydrophilic resin layer 30 . As a result, even if the hydrophilic resin layer 30 retains a large amount of water, the hydrophobic resin film 20 functions as a barrier layer and the surface of the metal plate 10 is less likely to corrode. Therefore, corrosion resistance can also be provided. That is, it becomes possible to maintain the surface function of the resin-laminated metal sheet for a longer period of time.

The resin-laminated metal sheet 1 according to this embodiment can be used in various fields. For example, resin-laminated metal sheets can be used as interior and exterior materials for transportation equipment such as automobiles, vehicles, and ships, transportation containers, industrial equipment, civil engineering and construction materials, sign panels, furniture, and OA equipment casings, utilizing their high self-cleaning function. It can be used for body parts, light electrical parts, housings, interior/lighting parts, ornaments, etc. Moreover, the resin-laminated metal sheet can be used for various sliding members such as gears, bearings, and rails, and for molds and the like, by making use of its high water lubrication function. Furthermore, the resin-laminated metal sheet 1 can be used for adhesive-bonded parts and the like by taking advantage of its high adhesion function.

<2. Manufacturing method of resin laminated metal plate>
Next, a method for manufacturing a resin-laminated metal sheet will be described. The following two methods are mentioned for the manufacturing method of a resin laminated metal plate.

(2-1. First method)
In the first method, first, the hydrophobic resin film 20 is produced by molding a hydrophobic resin into a film. Then, a hydrophilic resin is covalently bonded to the surface of the hydrophobic resin film 20 by the method described above. Here, the method of covalently bonding the hydrophilic resin to the surface of the hydrophobic resin film 20 is preferably the Graft-from method. Furthermore, among the Graft-from methods, the photopolymerization method and the living radical polymerization method are preferred. Furthermore, the photopolymerization method is preferable among the photopolymerization method and the living radical polymerization method. Thereby, a hydrophilic resin layer 30 is formed on the surface of the hydrophobic resin film 20 . Then, the hydrophobic resin film 20 with the hydrophilic resin layer 30 formed thereon is laminated on the metal plate 10 . A specific lamination method is as described above.

(2-2. Second method)
In the second method, the hydrophobic resin film 20 is laminated (formed) on the metal plate 10 . Here, the method of laminating the hydrophobic resin film 20 on the metal plate 10 is as described above. Then, a hydrophilic resin is covalently bonded to the surface of the hydrophobic resin film 20 by the method described above. Thereby, a hydrophilic resin layer 30 is formed on the surface of the hydrophobic resin film 20 . Here, the method of covalently bonding the hydrophilic resin to the surface of the hydrophobic resin film 20 is preferably the Graft-from method. Furthermore, among the Graft-from methods, the photopolymerization method is preferred. In the living radical polymerization method, metal ions may be eluted from the metal plate 10 during the polymerization reaction, making it difficult for the polymerization to proceed.

The resin-laminated metal sheet 1 according to this embodiment can be produced by either the first method or the second method. If the hydrophobic resin film 20 has self-holding property, both the first method and the second method can be implemented. Two methods can be implemented.

<1. Examples 1-13>
Next, an example of this embodiment will be described. In this example, the effects of this embodiment were confirmed by conducting the following tests.

(1-1. Preparation of metal plate)
As the metal plate, two types of zinc-based alloy plated steel plate with a thickness of 0.45 mm (Nippon Steel & Sumikin Superdimer (K08) (hereinafter also referred to as “SD steel plate”), hot-dip galvanized steel plate (Z18) (hereinafter, “GI Steel plate”), SUS plate (SUS430-2B, 0.6 mm thick), Al plate (A5052, 1.2 mm thick), and 0.3 mm thick titanium foil (JISH4600 standard product manufactured by Nippon Steel & Sumikin) were prepared. After subjecting these metal plates to an alkaline degreasing treatment, a chromate solution was applied to form a chromate film of about 45 mg/m ² on the metal plate surface.

(1-2. Preparation of PET film)
A PET film was prepared as an example of a hydrophobic resin film. Specifically, using a two-layer T-die, a white PBT/PET alloy layer containing 20% by mass of white pigment (PBT (Toraycon 1200S manufactured by Toray Industries) / PET (SP1344 manufactured by Unitika) = 70/30 ( Volume ratio)) and PET alloy layer (PET (SP1344 manufactured by Unitika) / VLDPE (ultra-low density polyethylene, DFDA-1137 manufactured by Dow) / compatibilizer (Bondfast 7L manufactured by Sumitomo Chemical) = 87/10/3 (volume A monochromatic film (imparted with a striped embossed pattern) was obtained. The total thickness of this monochromatic film was 100 μm, with a white PBT/PET alloy layer of 90 μm (upper layer) and a PET alloy layer of 10 μm (lower layer: layer in contact with the adhesive layer). The monochromatic film is called a white PET film. When the white PBT/PET alloy resin forming the upper layer and the PET/rubber/ionomer=87/10/3 alloy resin forming the lower layer were left in the air at 23° C. for 24 hours, the water absorption was 0.00. was 1%. Therefore, both resins are hydrophobic resins.

(1-3. Preparation of PVC film, PP film, PVF film)
As PVC film, PP (polypropylene) film, and PVF film, LE301 pattern film (100 μm thick, manufactured by Okamoto), Artbond PP film (145 μm, manufactured by Toppan Printing Co., Ltd.), Tedlar film (38 μm thick, manufactured by DuPont) prepared. The water absorption of each raw material resin was 0.5%, 0.01% and 0.4% when left in the air at 23° C. for 24 hours. Therefore, both resins are hydrophobic resins.

(1-4. Preparation of hydrophobic resin film laminated metal plate using film)
An adhesive was applied to the surface of the metal plate with a bar coater. Next, after heating the metal plate coated with the adhesive to the temperature (lamination temperature) shown in Table 1, the film was laminated and pressed. After pressurization, the metal plate was cooled to room temperature to obtain a hydrophobic resin film laminated metal plate. Eight kinds of hydrophobic resin film-laminated metal plates (1) to (8) were produced by changing the types of metal plates, films, and adhesives. Table 1 summarizes the compositions of the hydrophobic resin film laminated metal sheets (1) to (8).

In addition, a high collar manufactured by Nippon Steel & Sumikin Construction Materials Co., Ltd. was prepared. High color manufactured by Nippon Steel & Sumikin Kenzai Co., Ltd. is obtained by baking a polyester resin paint on the surface of the GI steel plate. A layered coating film was collected by edging Hicolor manufactured by Nippon Steel & Sumikin Construction Materials Co., Ltd. with hydrochloric acid, and the thickness and water absorption of the coating film were measured. As a result, the thickness of the coating film was 20 μm, and the water absorption was 0.15% when the coating film was left in the air at 23° C. for 24 hours. Therefore, HI-COLOR manufactured by Nippon Steel & Sumikin Construction Materials Co., Ltd. is a kind of hydrophobic resin film laminated metal sheet. In this example, Hi-Color manufactured by Nippon Steel & Sumikin Construction Materials Co., Ltd. was used as the hydrophobic resin film laminated metal plate (9).

(1-5. Elemental analysis of surface of hydrophobic resin laminated metal plate)
The elemental fraction in the vicinity of the surface of the hydrophobic resin film laminated metal plate was obtained by X-ray photoelectron spectroscopy (XPS, manufactured by APEX ULVAC-PHI Co., Ltd.). This result is called XPS analysis result (I).

(1-6. Preparation of resin laminated metal plate by lamination method (I))
In Examples 1 to 12, resin-laminated metal sheets were produced by lamination method (I). In the lamination method (I), a hydrophobic resin film is laminated on a metal plate in advance, and then a hydrophilic resin is covalently bonded to the surface of the hydrophobic resin film. Details will be described below.

(1-6-1. Purification of methacryloyloxyethyltrimethylammonium chloride (MTAC))
An aqueous solution of MTAC monomer was added dropwise to dehydrated tetrahydrofuran (THF) to reprecipitate the MTAC monomer. This purified the MTAC monomer.

(1-6-2. Surface purification of hydrophobic resin film laminated metal plate)
The surface of the hydrophobic resin film-laminated metal plate was washed with methanol to remove contaminants.

(1-6-3. Grafting by photopolymerization method)
An MTAC monomer was covalently bonded to the surfaces of the hydrophobic resin film laminated metal plates (1) to (9) by photopolymerization (that is, the surfaces were grafted). Specifically, the following processes were performed.

0.5 g of benzophenone was placed in a brown sample tube and dissolved in 4.5 g of acetone. The prepared solution was spin-coated on the surface (55×75 mm ² ) of the hydrophobic resin film laminated metal plate under conditions of 1,000 rpm for 1 minute. Then, 8.0 g of MTAC monomer was dissolved in 2.0 g of pure water. Then, the MTAC solution was spread over the surface of the hydrophobic resin film-laminated metal plate coated with benzophenone so that the MTAC solution sufficiently covered the surface. Then, the surface of the hydrophobic resin film laminated metal plate was irradiated with 1.5 kW ultraviolet rays (M015-L312, manufactured by Eyegraphics Co., Ltd.) for 2 minutes and 30 seconds at room temperature. As a result, polymethacryloyloxyethyltrimethylammonium chloride (PMTAC) polymer chains were covalently bonded to the surface of the hydrophobic resin film. Thus, resin-laminated metal sheets according to Examples 1 to 9 were produced. Table 2 summarizes the compositions of the resin-laminated metal sheets.

After the light irradiation, the resin-laminated metal plate was stirred in water for 5 hours to remove homo-PMTAC, which is a side reaction product, and wash it. After washing, the element fraction in the vicinity of the surface was determined by X-ray photoelectron spectroscopy (XPS) (XPS, manufactured by APEX Ulvac-Phi Co., Ltd.). This result is called XPS analysis result (II). As a result of comparing the XPS analysis results (I) and (II), the fraction of Cl and N elements due to PMTAC chains increased in (II) compared to (I). As a result, the PMTAC polymer chains could be covalently bonded to the surface of each hydrophobic resin film. Furthermore, the solubility of homo-PMTAC in 100 g of water at 25° C. and 1 bar was 0.1 g or more. Therefore, it was confirmed that the PMTAC polymer chain was a hydrophilic resin. Then, the molecular weight of the PMTAC polymer chain was measured by SEC (manufactured by Waters, SEC-MALS). As a result, Mn=1,972,000 and Mw=2,720,000. The graft density was calculated from the formula (1) using the Mn and the XPS element fraction analysis results. The result was 0.05 strands/ ^nm2 . The above formulation is for modifying a metal surface area of 55×75 mm ² with a polymer brush.

(1-6-4. Grafting of hydrophilic resin other than PMTAC)
Two new hydrophobic resin film laminated metal plates (1) were prepared, and a hydrophilic resin other than PMTAC was grafted onto the surfaces of these hydrophobic resin film laminated metal plates (1) by photopolymerization. Specifically, except for changing the monomer of the hydrophilic resin from MTAC to dihydroxypropyl methacrylate (DHMA) or 2-methacryloyloxyethylphosphorylcholine (MPC), 1-6-3. was processed in the same way as As a result, polydihydroxypropyl methacrylate (PDHMA) polymer chains or poly 2-methacryloyloxyethylphosphorylcholine (PMPC) polymer chains were covalently bonded to the surface of the hydrophobic resin film. Thus, resin-laminated metal sheets according to Examples 10 and 11 were produced. Table 2 summarizes the compositions of the resin-laminated metal sheets.

Moreover, as a result of comparing the XPS analysis results (I) and (II), it was confirmed that both the PDHMA polymer chains and the PMPC polymer chains were covalently bonded to the surface of the hydrophobic resin film. Further, the solubility of homo-PDHMA and homo-PMPC in 100 g of water at 25° C. and 1 bar was 0.1 g or more. Therefore, it was confirmed that both the PDHMA polymer chain and the PMPC polymer chain are hydrophilic resins. The graft densities of both PDHMA polymer chains and PMPC polymer chains were 0.04 to 0.06 chains/nm ² . Met.

(1-6-5. Grafting by living radical polymerization method)
A hydrophobic resin film-laminated metal plate (1) was newly prepared, and a hydrophilic resin was covalently bonded to its surface by living radical polymerization. Specifically, the following processes were performed.

23.6 ml (200 mmol) of 5-hexen-1-ol and 41.6 ml (300 mmol) of dehydrated triethylamine were added to 80 ml of dehydrated dichloromethane to prepare a first mixture. The first mixed solution was immersed in an ice bath, and a mixed solution (second mixed solution) of 70 ml of dehydrated dichloromethane and 37.1 ml (300 mmol) of α-bromoisobutyryl bromide was added dropwise to the first mixed solution, A third mixture was prepared. After dropping the second mixed liquid, the third mixed liquid was stirred in an ice bath for 6.5 hours and at room temperature for 10 hours. The precipitated salt was filtered off, and the filtrate was concentrated under reduced pressure. The concentrate was washed twice with 250 ml of 1N hydrochloric acid, twice with 250 ml of a saturated sodium bicarbonate solution, and once with 300 ml of water, and the organic layer was recovered. Magnesium sulfate was added to the collected organic layer to dry it, and the magnesium sulfate was removed by filtration. The filtrate was purified by distillation to obtain 1-(2-bromo-2-methyl)propionyloxy-5-hexene (BPH) as a colorless, transparent, highly viscous liquid. 25 ml (7.5 mol) of triethoxysilane and 0.3 ml of Karstedt's catalyst were added to 10 g (40 mmol) of the above BPH, and the mixture was stirred at 313 K for 24 hours. After completion of the reaction, unreacted triethoxysilane was distilled off under reduced pressure. The product ((2-bromo-2-methyl)propionyloxyhexyltriethoxysilane (BHE)) was purified by vacuum distillation at 150°C.

Then, 0.2 ml of 3-aminopropyltriethoxysilane (APTES) was dissolved in 20 ml of dehydrated toluene. The surface-washed hydrophobic resin film laminated metal plate (1) (10 × 40 mm) was immersed in a prepared dehydrated toluene/APTES solution and heated at 55°C for 40 hours. ). After heating, it was washed with toluene. Further, the hydrophobic resin film laminated metal plate (1) was immersed in hydrochloric acid adjusted to pH 4.5 for 24 hours to hydrolyze the alkoxy groups and convert them to cyanol. Thereafter, the hydrophobic resin film laminated metal plate (1) was washed with pure water and dried under reduced pressure.

8.9 g of ethanol and a 28% by mass aqueous ammonia solution were stirred and mixed, and the hydrophobic resin film laminated metal plate (1) prepared above (having silanolized APTES fixed on the surface) was immersed therein. 0.2 g of BHE dissolved in 8.9 g of ethanol was added dropwise to the immersed liquid while stirring. After being left at room temperature for 5 hours, the hydrophobic resin film laminated metal plate (1) was washed with ethanol and dried under reduced pressure. Thereby, the polymerization initiator (BHE) was immobilized on the surface of the hydrophobic resin film laminated metal plate (1).

Then, the hydrophobic resin film laminated metal plate (1) to which the polymerization initiator was fixed was immersed in 5 ml of a water/methanol mixed solution (1/4 by volume) in which 2.07 g of MTAC was dissolved. Furthermore, 0.1 ml of a 0.5 mol ethyl bromoisobutylate/methanol solution was added to the mixture, and argon was bubbled through the mixture for 30 minutes to remove oxygen from the mixture. Then, 34.4 mg of 2,2'-bipyridyl and 14.3 mg of copper (I) bromide were dissolved in 3 ml of methanol and freeze-degassed to remove oxygen. After freezing and degassing, 1.5 ml of the mixed liquid was added to the mixed liquid in which the hydrophobic resin film laminated metal plate (1) was immersed. Then, the mixed solution in which the hydrophobic resin film laminated metal plate (1) was immersed was heated to 333K with a bioshaker and stirred at 80 rpm for 48 hours. As a result, the PMTAC polymer chains were covalently bonded to the surface of the hydrophobic resin film-laminated metal plate (1). Thus, a resin-laminated metal sheet according to Example 12 was produced.

After heating and stirring, the resin film laminated metal plate was washed with methanol. Similar to grafting by photopolymerization, the element fraction near the surface was obtained by XPS, and the result, that is, the XPS analysis result (II) and the XPS analysis result (I) were compared. It was confirmed that it was covalently bonded to the surface of Furthermore, the molecular weight was measured from the recovered homo-PMTAC. Mn = 2,440,000, Mw = 2,533,000. Also, the grafting density was 0.02 strands/nm ² , which was smaller than that obtained by the photopolymerization method. This is presumed to be the result of the generation of deactivated raw materials due to the large number of elementary reaction steps compared to the photopolymerization method. Furthermore, covalent bonding of PMTAC to a hydrophobic resin film by this living polymerization method was effective up to a size of 10 × 40 mm, but when the scale was expanded to 55 × 75 mm ² , stable covalent bonding could not be achieved. I didn't. The reason for this is thought to be that when the scale becomes large, oxygen is mixed into the polymerization system and acts as a radical scavenger, making it impossible to graft a high molecular weight polymer chain.

(1-7. Preparation of resin laminated metal plate by lamination method (II))
In Example 13, a resin-laminated metal sheet was produced by the lamination method (II). Lamination method (II) involves forming a hydrophilic resin layer on a hydrophobic resin film and then laminating this hydrophobic resin film on a metal plate. Details will be described below.

First, the surface of the white PET film was washed with methanol. Next, the above 1-6-3. PMTAC polymer chains were covalently bonded to the surface of the white PET film by performing the same treatment. Then, the surface of the white PET film was washed with water to remove homo-PMTCA.

Then, the white PET film to which the PMTAC polymer chains were covalently bonded was laminated on the SD steel plate by the same process as the manufacturing of the hydrophobic resin film laminated metal plate (1). Thus, a resin-laminated metal sheet according to Example 13 was produced. After that, the above 1-6-3. The element fraction on the surface of the resin-laminated metal plate was obtained in the same manner as in the above. The measurement result of the element fraction, that is, the XPS analysis result (II) was compared with the XPS analysis result (I). As a result, it was confirmed that the PMTCA polymer chains were covalently bonded to the surface of the hydrophobic resin film, although the element fraction attributable to the PMTCA polymer chains was slightly lower than in Example 1. The decrease in the element fraction caused by the PMTCA polymer chains can be presumed to be due to thermal deterioration of some of the PMTCA polymer chains due to heating during lamination of the white PET film. The grafting density was 0.05 strands/ ^nm2 .

(1-8. Performance evaluation)
Next, in order to evaluate the performance of the resin-laminated metal sheets according to Examples 1 to 13, the following performance evaluation tests were conducted. Table 2 summarizes the results.

(1-8-1. Contact angle)
In order to confirm the hydrophilicity of the surface of the resin-laminated metal sheet, the contact angle of a 1 μl water droplet on the surface of the resin-laminated metal sheet under wet conditions was measured using Theta T-2000 (manufactured by Biolin Scientific). Rating ◯: 20° or less, Δ: more than 20° and 60° or less, ×: more than 60°.

(1-8-2. Evaluation of initial self-cleaning function)
A model contaminant, which is used to evaluate the antifouling properties of unit bath wall materials, was attached to the surface of a resin-laminated metal plate. The model contaminants are shown in Table 2. After standing for 1 hour, the resin-laminated metal plate was immersed in distilled water and ultrasonically cleaned for 1 minute. A quantitative comparison was made of the weight of the contaminants or the residual contact area before and after cleaning. Rating ⊚: 100% removable, ∘: 0 to 10% residual, Δ: 10 to 20% residual, ×: 30% or more residual.

(1-8-3. Evaluation of durability of self-cleaning function)
The resin-laminated metal plate was immersed in a 5% commercially available bath detergent aqueous solution and slid 10,000 times in the longitudinal direction with a nylon sponge while applying a vertical weight of 500 g. After the test, the surface of the resin-laminated metal plate was ultrasonically washed with distilled water for 5 minutes to remove the detergent. Next, the same test as for the initial self-cleaning function was conducted to evaluate the durability of the self-cleaning function.

(1-8-4. Evaluation of water lubricity)
In water, the surface of the resin-laminated metal plate was rubbed with a glass ball. The coefficient of dynamic friction at this time was measured to evaluate water lubricity. The glass ball was linearly slid at room temperature under the conditions of a vertical load of 0.49 N (137 MPa in terms of stress), a sliding speed of 10 ⁻⁵ to 10 ⁻¹ m/s, and an amplitude of 20 mm. The maximum value within this sliding speed range was adopted as the dynamic friction coefficient. Rating ⊚: coefficient of dynamic friction of 0.05 or less, ○: more than 0.05 and less than 0.08, Δ: more than 0.08 and less than 0.10, x: more than 0.1.

(1-8-5. Evaluation of corrosion durability)
A 2000-hour salt spray test was conducted using a mass % NaCl aqueous solution in accordance with the neutral salt spray test specified in JISZ2371:2000. The occurrence of corrosion after the test was visually evaluated. Rating ○: no rust, △: white rust, ×: red rust

<2. Comparative Examples 1 to 6>
In the following comparative examples, the by-product homo-PMTAC recovered in Example 1 was used as homo-PMTAC.

(2-1. Comparative Example 1)
In Comparative Example 1, the initial self-cleaning function, water lubricity, and corrosion resistance of the SD steel plate were evaluated. Initial self-cleaning capability testing indicated that none of the model contaminants could be removed with water alone. Furthermore, the coefficient of dynamic friction in water was as high as 0.45, and almost no water lubricity was observed. In the corrosion durability test, white rust occurred.

(2-2. Comparative Example 2)
In Comparative Example 2, the initial self-cleaning function of the hydrophobic resin film laminated metal plate (1) was evaluated. Only the hair cosmetics could be removed by washing with water, but the others were not.

(2-3. Comparative Example 3)
In Comparative Example 3, a metal plate was coated with a hydrophilic resin. Specifically, homo-PMTAC was dissolved in water and applied onto an SD steel plate. Then, the wet contact angle of the steel sheet surface was measured according to the above 1-8-1. was measured in the same manner as The contact angle is 78°, not sufficiently hydrophilized. It is thought that the density of the PMTAC polymer chains on the surface of the metal plate is low, and even if water molecules enter the hydrophilic resin layer composed of the PMTAC polymer chains, the osmotic pressure does not rise. As a result, the PMTAC polymer chains did not extend perpendicularly from the surface of the metal plate, and the surface was not sufficiently hydrophilized.

(2-4. Comparative Example 4)
In Comparative Example 4, a hydrophilic resin polymer brush was formed directly on the surface of the metal plate. Specifically, the surface of the SD steel plate was cyanolized by the same treatment as in Example 12. BHE was bound to this by the same treatment as in Example 12. After the BHE bonding, MTAC was grown from the surface of the steel sheet by a living radical polymerization method (specifically, by the same treatment as in Example 12). As a result, an SD steel sheet having PMTAC polymer chains covalently bonded to the surface was obtained. Next, the initial self-cleaning function and corrosion durability of the SD steel plate were evaluated. A self-cleaning function equivalent to that of Example 12 was able to be exhibited against the model contaminants at the initial stage. However, after the salt spray test, red rust occurred all over the surface. Since the hydrophilic resin polymer brush is formed directly on the surface of the metal plate, it has no barrier property against water molecules, and corrosion resistance could not be expressed.

(2-5. Comparative Example 5)
In Comparative Example 5, a hydrophilic resin was coated on a hydrophobic resin film-laminated metal plate. Specifically, homo-PMTAC dissolved in methanol was applied to the surface of the hydrophobic resin film laminated metal plate (1) and dried. After drying, the initial self-cleaning function of the hydrophobic resin-laminated metal plate coated with the hydrophilic resin was evaluated. Since the hydrophobic resin film and the hydrophilic resin polymer chains were not covalently bonded, the hydrophilic resin layer was peeled off during ultrasonic cleaning. Therefore, when the self-cleaning function of the hydrophobic resin film-laminated metal sheet was tested again (durability evaluation was performed), the self-cleaning function was lost.

(2-6. Comparative Example 6)
In Comparative Example 6, a hydrophilic resin film was formed on a metal plate, and a hydrophilic resin film was further formed thereon. Specifically, homo-PMTAC dissolved in water was bar-coated on the surface of the SD steel plate, and then vacuum-dried to form a hydrophilic resin film having a thickness of 20 μm on the SD steel plate. Then, in the same manner as in Example 1, PMTAC polymer chains were covalently bonded to the hydrophilic resin film. Corrosion durability of the resin-laminated metal sheet was evaluated. As a result, rust occurred on the entire surface of the metal plate. Corrosion durability could not be expressed because there was a hydrophilic resin film instead of a hydrophobic resin film between the hydrophilic resin layer and the metal plate.

As described above, Examples 1 to 13, which satisfy the requirements of the present embodiment, have extremely excellent surface functions and can maintain the surface functions for a longer period of time, but Comparative Examples 1 to 6 No such results were obtained.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

1 Resin laminated metal plate 10 Metal plate 20 Hydrophobic resin film 30 Hydrophilic resin layer

Claims (5)

a metal plate;
a hydrophobic resin film with a thickness of 1 μm to 2 mm formed on the surface of the metal plate and containing a hydrophobic resin as a matrix or continuous phase;
a hydrophilic resin layer formed on the surface of the hydrophobic resin film and containing a hydrophilic resin covalently bonded to the surface of the hydrophobic resin film;
A method for producing a resin-laminated metal sheet , characterized in that the hydrophilic resin has a density of 0.01 chains/nm ² or more,
a step of producing the hydrophobic resin film;
forming the hydrophilic resin layer on the hydrophobic resin film by covalently bonding a hydrophilic resin to the surface of the hydrophobic resin film by photopolymerization or living radical polymerization;
and laminating the hydrophobic resin film having the hydrophilic resin layer formed thereon on the metal plate. 2. The method of manufacturing a resin-laminated metal sheet according to claim 1, wherein the hydrophilic resin contains a dipolar ion-containing resin. 3. The method for manufacturing a resin-laminated metal sheet according to claim 1, wherein said hydrophobic resin film contains a thermoplastic resin as said hydrophobic resin. The hydrophobic resin film contains, as the thermoplastic resin, any one or more selected from the group consisting of polyester resin, polyvinyl chloride resin, polyolefin resin, fluororesin, and acrylic resin, The method for manufacturing a resin-laminated metal sheet according to claim 3. 5. The method for manufacturing a resin-laminated metal sheet according to claim 1, wherein the hydrophobic resin film contains a thermosetting resin as the hydrophobic resin.

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