JP6357855B2 - Composite material having high water and oil repellency and method for producing the same - Google Patents

Description

  The present invention relates to a composite material that can maintain high water and oil repellency for a long period of time and can maintain its function even when wrinkles occur on the surface due to external damage, and a method for producing the same.

  As one of the technology for enhancing the functionality of the material surface, there is an artificial water / oil repellency technology for the material surface. If water and oil repellency can be imparted to a solid surface, for example, if it is an outer wall of an automobile body or a building, it prevents dirt and scale from adhering to rainwater and muddy water, and if it is a window glass, visibility due to an antifogging effect It can be expected to have an effect of waterproofing and antifouling for clothing, prevention of icing and snowing for signs and antennas, and prevention of fingerprint adhesion for touch panels such as mobile phones.

  The wettability to a solid surface generally depends on the chemical factor (surface tension) and geometric factor (surface roughness) of the solid surface. In order to produce a water / oil repellent surface, it is first necessary to reduce the surface tension of the solid. In addition, by imparting a concavo-convex structure to the solid surface, it becomes possible to further improve the water and oil repellency. For example, Non-Patent Document 1 discloses an example in which water and oil repellency is imparted by coating with polyethylene terephthalate (PTFE). Non-Patent Document 2 discloses an example in which water- and oil-repellency is achieved by chemically adsorbing an adsorptive organic alkyl molecule having a small surface tension on a smooth glass surface. In Non-Patent Document 3, anisotropic ion etching of a silicon substrate is used to build a shape called a reentrant structure on the surface, and then the surface is chemically adsorbed with an adsorbing fluorine-based organic alkyl molecule. An example of water and oil repellency is disclosed. Non-patent documents 1 and 2 are the effects of chemical factors (surface tension), and Non-patent document 3 is the best use of the effects of both chemical factors (surface tension) and geometric factors (surface roughness). It was proposed for the purpose. In contrast, in Non-Patent Document 4, the surface structure of a silicon substrate that has been roughened in advance is transferred to an epoxy resin, whereby a columnar structure (width 300 nm, height 500 nm or 5 μm) has an uneven structure arranged at intervals of about 1 to 2 μm, and then fluorine-based organic alkyl molecules, which are adsorbing organic molecules, are chemically bonded to the substrate surface of the uneven structure to form an organic molecule intermediate layer. In addition, there has been proposed a method in which water and oil repellency is exhibited by a structure in which a liquid fluorine-based lubricant having a viscosity is applied. In this proposal, the surface shape (geometric factor) plays a role of holding a fluorine-based lubricant layer having fluidity on the surface of the substrate, and an organic material in which fluorine-based organic alkyl molecules are chemically bonded to the surface of the substrate. By forming the molecular intermediate layer, the outflow of the fluorine-based lubricant from the substrate surface is suppressed by intermolecular attractive force. High water and oil repellency is aimed at manifesting only by chemical factors. Unprecedented high water and oil repellency due to the small surface tension derived from the fluorocarbon chain and the effect of vibration of molecules derived from the liquid. In addition, it is disclosed that even if wrinkles occur on the surface due to external damage, a fluorine-based lubricant flows into the wrinkles and self-healing properties that maintain water and oil repellency performance are exhibited.

Supervised by Takaomi Satokawa, "Latest Fluoropolymer Coating Technology", Epotech Co., Ltd., issued in April 1989 P. E. Hintze, L. M. Calle, Electrochim. Acta, 51, (2006), 1761. A. Tuteja, W. Choi, M. L. Ma, J. M. Mabry, G. H. McKinley, R. E. Cohen, Proc. Natl. Acad. Sci., U. S. A., 105, (2008), 18200. T. Wong, S. H. Kang, S. K. Y. Tang, E. J. Smythe, B. D. Hatton, A. Grinthal, J. Aizenberg, Nature, 477, (2011), 443-447.

  However, all the cases introduced in Non-Patent Documents 1 to 4 have insufficient water and oil repellency, insufficient sustainability to maintain water and oil repellency over a long period of time, or external damage. When wrinkles occur on the surface, the water / oil repellency self-healing performance was not at a satisfactory level.

  For example, in Non-Patent Document 1, polyethylene terephthalate (PTFE) can be expected to have water repellency, but often has low oil repellency, and it is based on polyethylene terephthalate (PTFE) due to pinholes generated during film formation. It has been found that the adhesiveness with the metal plate decreases and peels. Non-Patent Document 2 solves this problem by introducing chemical bonds to secure the adhesion between the substrate and the coating layer, and Non-Patent Document 3 is based on a plan to further enhance its water and oil repellency. An uneven structure has been introduced on the surface of the material, but its water and oil repellency depends on organic alkyl molecules fixed to the surface of the substrate by chemical bonds, so it is repellent when wrinkles occur on the surface due to external damage. Since the function of self-repairing the water / oil repellency performance is not secured, it is inevitable that the performance deteriorates. Non-Patent Document 4 expresses high water and oil repellency and self-healing function that can maintain it, but because of the large uneven structure of the base material, it has a fluid fluorine system that is held on the surface of the base material. The function of holding the lubricant layer by the organic molecular intermediate layer was not sufficiently high, and the durability for stably exhibiting the water and oil repellency performance over a long period of time was not sufficient.

  As described above, for the purpose of developing high water and oil repellency and self-repairing properties, as in Non-Patent Document 4, a substrate having an uneven surface, a fluid liquid fluorine-based lubricant layer, and those Although a structure composed of an organic molecular intermediate layer that binds to each other has been proposed as well, in order to obtain a metal plate with high durability of this function, a columnar structure (see FIG. 1) ( A structure with a concavo-convex structure with a width of 300 nm and a height of 500 nm or 5 μm) arranged at intervals of 1 to 2 μm is further refined to a concavo-convex structure of about 10 to 300 nm as shown in FIG. It was speculated that improving the function of holding a sufficient amount of a fluorine-based lubricant capable of expressing the function on the surface of the substrate was one of the solutions, but the metal substrate surface was processed into such a fine pore structure, An organic molecular intermediate layer as described above is formed and coated thereon, and a fluorine-based lubricant is further formed thereon. It is difficult to find a specific method that can be used to form the material, and industry development is considering application studies such as anti-icing using the characteristics of the surface with the fluorine-based lubricant layer held as the outermost layer, and different substrate materials. Proceeded to study on the manifestation of effects in Japan.

  Establishing a technology to form an organic molecular intermediate layer in the microporous structure of the substrate has been realized in order to improve the durability of high water and oil repellency and self-healing properties, even though it was supposed to be a solution. The present inventor has examined the reason why no specific method has been proposed. When the pores on the surface of the metal plate are made finer, the adsorbing organic molecules forming the organic molecule intermediate layer enter the fine pores. It became difficult to form an organic molecular intermediate layer inside the pores. As a result, the fluorine-based lubricant formed on the organic molecular intermediate layer does not sufficiently penetrate into the pores, so that self-repairability and sustainability cannot be improved.

  The present inventor has examined in detail the reason why it is difficult to form an organic molecule intermediate layer in the pores. The adsorbing organic layer is formed when the organic molecule intermediate layer is formed by chemical adsorption between the adsorbing organic molecule and the substrate. It has been found that this is due to molecular self-condensation. The adsorptive organic molecules used to form the organic molecular interlayer are hydrolyzed by a small amount of water and adsorbed by dehydration condensation with hydroxyl groups on the surface of metal materials and metal oxides. Also self-condensate to form a polymer. Therefore, even if the adsorptive organic molecule has a size that can penetrate into the micropores with a single molecule, it cannot penetrate into the micropores when it becomes a polymer, and precipitates as an aggregate outside the micropores. It is difficult to form an organic molecular interlayer in the pores. For these reasons, producing a metal material having micropores holding a fluorine-based lubricant layer via an organic molecular intermediate layer is limited to a surface structure with an uneven size as in Non-Patent Document 4. It was.

  Therefore, the present inventor considered that it is important to suppress the self-condensation of the adsorptive organic molecules and reduce the formation of the polymer in order to solve this problem. It is found that organic silanes that are commonly used tend to form polymers, but self-condensation tends to be difficult to occur when adsorbing organic molecules containing phosphorus functional groups such as phosphoric acid and phosphonic acid are used. It was.

  However, agglomeration cannot be prevented simply by forming an organic molecular intermediate layer with adsorbing organic molecules having phosphorus functional groups, and it is important to remove adsorbed water on the surface of metal materials, which causes self-condensation. I found out. Although adsorbed water exists on the surface of metal or metal oxide material, the amount of adsorbed water in metal materials with fine pores is larger than that on a smooth surface because adsorbed water is also present in the fine pores. It is considered that promotes hydrolysis of the adsorptive organic molecule, and as a result, promotes formation of a polymer and precipitation as an aggregate. By removing adsorbed water on the surface of metal materials and using an adsorbing organic molecule containing a phosphorus-based functional group for the formation of an organic molecule intermediate layer, the formation of aggregates due to self-condensation of the adsorbing organic molecule is suppressed. Furthermore, it has been found that an organic molecular intermediate layer can be formed in the fine pores, and the fluorine-based lubricant can be retained in the fine pores. By the means described above, the present inventor has solved the problems that cannot be achieved by those skilled in the art, and has arrived at the present invention.

  Further, the present inventors have found that there are pore diameter ranges, pore lengths, and porosities of specific micropores for exhibiting self-repairability and sustainability.

The gist of the present invention is as follows.
(1) A composite material having a fine lubricant and a fluorine-based lubricant layer through an organic molecular intermediate layer on the surface of a metal material that does not contain moisture, and the pore size of the fine pore is 10 nm or more than or equal to 300 nm and hole length is at 100 nm or more, and the organic molecule intermediate layer has a fluoroalkyl chain or an alkyl chain, of the absorptive organic molecules with phosphonic acid group or phosphoric acid group at one end, a layer with the phosphonic acid group or the surface of the metallic material having the fine pores and the phosphate group is formed by reaction and the fluorine-based lubricant layer is perfluoroalkyl ether or perfluoroalkyl amine or A composite material characterized by being a perfluorocarbon.
(2) The composite material according to claim 1, wherein the pore length of the micropore is 1 μm or more and 50 μm or less.
(3) The composite material according to any one of claims 1 and 2 , wherein the metal material having fine pores has a porosity of 10% or more and 40% or less.
(4) absorptive organic molecule forming organic molecule intermediate layer is a composite material according to claim 1 having a fluoroalkyl chain having 6 or more carbon atoms which have a phosphonic acid group or phosphoric acid group .
(5) After forming fine pores on the metal material surface and removing moisture from the metal material surface by heating and drying at 100 ° C. or more and 300 ° C. or less in an air or dry gas atmosphere, a phosphonic acid group or phosphoric acid An alkyl molecule or a fluoroalkyl molecule having a group is formed on the surface of the metal material via the phosphonic acid group or the phosphoric acid group , and an organic molecular intermediate layer is formed on the surface of the metal material, and a perfluoroalkyl ether, perfluoroalkylamine, or perfluoroalkyl is further formed. A method for producing a composite material in which a fluorine-based lubricant composed of carbon is coated on the metal material.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the metal material excellent in the self-healing performance which maintains high water-oil-repellency with respect to a wrinkle, and maintains wettability over a long term.

A schematic diagram of the prior art is shown. The schematic diagram of this invention is shown. An appearance photograph (with a white pattern by an aggregate) of a metal material in which an organic molecular intermediate layer is formed on a surface having fine pores is shown. An appearance photograph (no white pattern due to aggregates) of a metal material in which an organic molecular intermediate layer is formed on a surface having micropores is shown.

  The present invention is described in detail below.

  The present invention is a metal material having fine pores that hold a fluorine-based lubricant layer through an organic molecular intermediate layer, and maintains high water and oil repellency for a long period of time. Further, wrinkles occur on the surface due to external damage. However, it has the feature that the function can be maintained.

<Metal material>
As the metal material of the present invention, any metal material that can form a fine pore structure on the surface can be used. Although not specifically limited, for example, as commercially available general metal materials, cold-rolled steel sheets specified in JIS G 3141, stainless steel sheets such as SUS304 and SUS430, aluminum and aluminum such as JIS H 4000 Examples include alloy plates and titanium plates such as JIS H 4600. In particular, steel materials, aluminum, and titanium are preferable because a fine pore structure can be formed by utilizing anodization (porous chemical conversion).

<Organic molecular interlayer>
The organic molecular intermediate layer in the present invention increases the affinity with the fluorine-based lubricant layer, so that when the droplet comes into contact with the fluorine-based lubricant layer from the outside, the fluorine-based lubricant layer is more than the droplet. By preferentially wetting the substrate surface through the organic molecular intermediate layer, it plays the role of preventing the outflow of the fluorine-based lubricant layer. At that time, the smaller the surface tension of the organic molecular intermediate layer and the higher the density of the organic molecular intermediate layer corresponding to the uneven structure on the surface of the base material, the easier the fluorine-based lubricant layer is held on the surface of the base material. This is because the smaller the surface tension, the higher the affinity with the fluorine-based lubricant layer than the adhering droplets, and the organic molecule intermediate layer uniformly coats the substrate surface. This is because it becomes difficult to be affected by the tension. For this reason, the organic molecular intermediate layer of the metal plate of the present invention has a fine chain of linear or branched (branched) molecules having a fluoroalkyl chain or an alkyl chain as a main chain and having a phosphorus functional group at one end. It is a layer formed by chemically bonding to the surface of a metal material having phosphine via a phosphorus functional group.

  The organic molecule intermediate layer preferably binds the adsorbing organic molecules at a high density even on the surface of the metal material or inside the micropores formed on the surface of the metal material. Is preferably a compound that is less likely to self-condense before bonding to the metal plate surface and less likely to aggregate. From this viewpoint, the functional group of the adsorptive organic molecule that binds to the metal material is a phosphorus-based functional group such as phosphoric acid or phosphonic acid. If it is a phosphorus functional group, it becomes easy to avoid the self-condensation and aggregation before couple | bonding with the metal plate surface. Moreover, if it is a phosphorus functional group, it can fix | immobilize by a covalent bond by the dehydration condensation reaction with the hydroxyl group on the metal material surface. Such bonds are stronger than physical bonds, and the fluorine-based lubricant layer can be stably held in the microstructure and on the surface thereof. Organosilanes are common except for phosphorus functional groups, but organic silanes are highly reactive with water, and molecules tend to self-condensate, so they tend to be condensed. For this reason, in the structure having fine pores, the inside of the pores cannot be uniformly coated, and is easily deposited as a condensate on the pores, so that a self-repairing action and sustainability for soot cannot be obtained.

In addition, the organic molecular interlayer of the present invention plays a role of holding the fluorine-based lubricant layer in the micropores and on the surface of the metal material by intermolecular interaction, so that the main chain of the adsorptive organic molecule is in contact with the fluorine-based lubricant. It is a fluoroalkyl chain or an alkyl chain with high affinity. The number of carbon atoms in the main chain alkyl chain is not particularly limited, but is preferably 6 or more. If it is less than 6, the ratio of the hydrophilic phosphorus functional group to the organic molecular chain length increases, so that the surface tension increases and the retention of the fluorine-based lubricant layer tends to weaken, which is not preferable. In addition, since the intermolecular interaction between the organic molecule intermediate layer and the fluorine-based lubricant layer increases as the surface tension of the adsorptive organic molecule decreases, one end of the adsorptive organic molecule opposite to the phosphorus functional group is It preferably has a trifluoromethyl group or a methyl group. The surface tension of the trifluoromethyl group (CF _3- ) is 6 mN m ^-1 , and the surface tension of the methyl group (CH _3- ) is 22 mN m ^-1 . The surface tension of -CF ₂ -CF _2- is 18 mN m ^-1 and the surface tension of -CH ₂ -CH _2- is 31 mN m ^-1 . Therefore, a more preferable adsorptive organic molecule has a phosphorus functional group, one end on the opposite side is a trifluoromethyl group (CF _3- ), and consists of a fluoroalkyl chain (-CF ₂ -CF _2- ). Examples thereof include perfluoroalkyl phosphonic acid (polyfluoroalkyl phosphonic acid) and perfluoroalkyl phosphoric acid (polyfluoroalkyl phosphoric acid), which are organic fluorine molecules. For example, the following compounds are exemplified when specifically shown. 1H, 1H ', 2H, 2H'-Perfluorododecyl-1-phosphonic acid, 1H, 1H', 2H, 2H'-Perfluorodecyl-1-phosphonic acid, 1H, 1H ', 2H, 2H'-Perfluorooctyl-1-phosphonic acid , 1H, 1H ', 2H, 2H'-perfluorododecyl phosphate, 1H, 1H', 2H, 2H'-perfluorodecylphosphate, 1H, 1H ', 2H, 2H'-perfluorooctyl phosphate, n-Octadecylphosphonic acid, n-Tetradecylphosphonic acid, n -Dodecylphosphonic acid, n-Decylphosphonic acid, n-Octylphosphonic acid, n-Hexylphosphonic acid, Octadecyl dihydrogen phosphate, Tetradecyl dihydrogen phosphate, Mono-n-dodecyl phosphate, Decyl hydrogen phosphate, Octyl dihydrogen phosphate, Hexyl dihydrogen phosphate.

<Fluorine-based lubricant layer>
The fluorine-based lubricant layer in the present invention is held on the surface of a metal material having an organic molecular intermediate layer and not only continuously exhibits high water and oil repellency to droplets coming into contact with the outside, but also on the surface of the substrate. Even when wrinkles occur, it is necessary for the fluorine-based lubricant to penetrate into the wrinkles to maintain water and oil repellency. As a characteristic required for the realization, the fluorine-based lubricant layer needs to have a low surface tension. The water / oil repellency with droplets coming into contact with the outside increases as the surface tension of the lubricant layer decreases. In addition, since the fluorine-based lubricant layer is a viscous liquid, the outermost surface can be smooth and can vibrate at a molecular level, so that uniform wetting without depending on the part and high water / oil repellency are possible. Moreover, since it has fluidity | liquidity, even if wrinkles generate | occur | produce, it can penetrate | invade into a collar part and self-restoration property is also attained. However, it is also required that the fluorine-based lubricant does not mix with the droplets that come into contact. In order to satisfy these characteristics, the fluorine-based lubricant layer in the present invention is a liquid perfluoroalkyl ether, perfluoroalkylamine, or perfluorocarbon having a fluorocarbon as a main component and low volatility. If it is these, it will not mix with the droplet adhering to a base material, but it is hold | maintained also on the base-material surface by the organic molecule intermediate | middle layer of a low surface tension. Furthermore, since it is a viscous liquid, not only self-healing property for wrinkles is realized, but also high water and oil repellency can be obtained by reducing the affinity with attached droplets by vibration at the molecular level.

Fluorine-based lubricants generally decrease in volatility when the molecular weight increases, but the viscosity increases. Conversely, when the molecular weight decreases, the volatility increases, but the viscosity decreases. In the perfluoroalkyl compound in the present invention such as perfluoroalkyl ether and perfluoroalkylamine, the average molecular weight is preferably 500 or more and 11,000 or less. If it is less than 500, the volatility tends to be high and the sustainability tends to be insufficient, and if it exceeds 11000, the viscosity tends to be high. This is to be seen. At this time, the volatilization rate of the fluorine-based lubricant is not particularly limited, but in the case of a general fluorine-based lubricant such as the above-mentioned perfluoroalkyl ether, an organic molecular intermediate layer is formed on the micropores. The evaporation loss of the fluorine-based lubricant layer before and after evaporation when holding a metal material holding the fluorine-based lubricant layer in an electric furnace at 66 ° C for 1 hour in the open air is 50 gm ^-2 The following is preferred. For example, in the ASTM standard, the evaporation loss of the fluorine-based lubricant per 22 hours at 66 ° C. in ASTM D972-02 (2003) corresponds to about 2% or less by weight.

When wrinkles occur on the surface of the base material, the microporous structure of the buttock and the structure of the organic molecular intermediate layer are destroyed, but the fluorine-based lubricant held in the vicinity of the buttock penetrates into the buttock and By covering, self-repairing properties are manifested. The fluorine-based lubricant, for example, DuPont Co. Krytox (R) (GPL 100, 101, 102, 103, 104), 3M Co. ^{Fluorinert TM (FC-70, 43} , 40) are preferably exemplified The

<Pore diameter of fine pore structure>
The average pore diameter of the fine pore structure formed in the metal plate of the present invention affects the holding force of the fluorine-based lubricant layer in the pores by the organic molecular intermediate layer formed in the fine pores. If the pore diameter is too large, the intermolecular force of the organic molecular intermediate layer formed on the surface of the fine pores to the fluorine-based lubricant tends to be small, and the dissipation of the fluorine-based lubricant tends to increase. On the other hand, when the pore diameter is small, the binding force of the fluorine-based lubricant layer by the organic molecular intermediate layer is increased, and a sufficient effect of the fluorine-based lubricant layer cannot be obtained. The average pore diameter of the present invention is 10 nm or more and 300 nm or less.

  If it is less than 10 nm, the proportion of the fluorine-based lubricant restrained by the organic molecular interlayer due to intermolecular interaction increases, and the mobility of the fluorine-based lubricant tends to be impaired, and the surface is wrinkled due to external damage. There is a tendency that sufficient self-repairability is not obtained. Also, it is difficult to form the organic molecular intermediate layer uniformly according to the present invention. Above 300 nm, the proportion of fluorine-based lubricants constrained by the organic molecular interlayer due to intermolecular interaction decreases, and the dissipation of fluorine-based lubricants from the pores increases, stabilizing water and oil repellency. It becomes difficult to maintain. More preferably, it is 50 nm or more and 200 nm or less. Within this range, the intermolecular interaction can maintain the binding force of the organic molecular intermediate layer and the fluidity of the fluorine-based lubricant. Even if wrinkles occur, the function can be maintained. Here, the average pore diameter means an average value of pore diameters measured for 10 or more holes observed in an arbitrary field of view in surface SEM (scanning electron microscope) observation of a fine pore structure.

<Porosity of microporous structure>
The average porosity in the microporous structure formed in the metal plate of the present invention is the area ratio (%) of micropores per apparent area of the metal plate, but the amount of fluorine-based lubricant retained on the metal material. Affect. That is, when the pore length of the fine pore structure is in a preferable range, the amount of fluorine-based lubricant retained on the substrate surface can be increased as the porosity increases. Therefore, the average porosity of the present invention is preferably 10% or more and 40% or less. Within this range, while maintaining the strength of the microporous structure, the effect of improving the retention of the fluorine-based lubricant layer due to the surface roughness caused by geometric factors can be obtained. If it is less than 10%, since the ratio of the smooth portion of the metal plate is large, the self-repairing property against wrinkles tends to be low, which is lower than the allowable value capable of realizing the present invention. On the other hand, if it exceeds 40%, it becomes difficult to form a fine structure substantially, and the strength of the pore structure also decreases. For example, when forming a microporous structure by anodic oxidation, the pores are closely packed, but if it exceeds 40%, the pores are bonded to each other or the pore walls are missing, resulting in high mechanical durability. Lower. More preferably, it is 20% or more and 30% or less. If it is this range, the intensity | strength of a base material can be kept at a high level, and it is easy to make industrially. Here, the average porosity refers to the area ratio of pores (porosity) in the plane of the metal plate per field of view measured in 10 arbitrary fields of view in the surface SEM (scanning electron microscope) observation of the microporous structure. ) Is the average value.

<Hole length of fine pore structure>
The average pore length of the microporous structure formed in the metal plate of the present invention affects the maintenance of the microporous structure against soot generated on the substrate surface and the amount of fluorine-based lubricant retained. In other words, if the hole length is large, even if wrinkles occur on the surface of the metal material due to external factors, there is a higher possibility that a fine hole structure will remain under the wrinkles, and it is necessary to maintain self-repairability. A fluorine-based lubricant can be supplied. On the other hand, if the pore length is too small, the fine pore structure having the organic molecular intermediate layer is lost due to soot, and the underlying metal material is exposed, so that the self-repairing effect is reduced. The average pore length of the present invention is 100 nm or more and 50 μm or less.

  If it is less than 100 nm, the damage to the micropore structure on the soot is large, and the amount of fluorine-based lubricant that can be retained in the pores is not large, so that the self-repairability is insufficient. If it exceeds 50 μm, the effect of improving the water / oil repellency and self-healing performance by increasing the hole length will be saturated, which is not economical. More preferably, it is 1 μm or more and 50 μm or less. Within this range, it is possible to achieve both economic efficiency while maintaining high self-repairability and long-term stability against wrinkles. The average hole length of the present invention means an average value of hole lengths measured for 20 or more holes observed in an arbitrary field of view in cross-sectional SEM (scanning electron microscope) observation of a micropore structure.

<Method for forming micropores>
There are no particular limitations on the method of forming the micropores, and any dry process, wet process, top-down process, or bottom-up process can be used as long as the above-described micropore structure can be formed on the surface of the metal material. It doesn't matter. Examples of these include anodic oxidation (porous chemical conversion), photolithography, ion etching, chemical etching, electrolytic etching, and the like. In addition, a metal material having a metal oxide or metal hydroxide including a natural oxide film on the surface of the metal material, or a metal oxide or metal hydroxide is formed on the surface in the process of forming a microporous structure. Are also included in the present invention.

<Moisture removal method>
In the present invention, when the organic molecular intermediate layer is formed on the surface of the metal material having a microporous structure, it is essential to remove moisture from the substrate surface. If moisture remains on the surface of the substrate, including inside the micropores, self-condensation of the adsorptive organic molecules is promoted, and not only aggregates are formed on the surface of the substrate, but also a uniform organic in the micropores. Formation of the molecular interlayer is inhibited. Further, in the case of a metal material having a hydrated oxide formed on the surface, moisture may be released by heating or the like, and the adsorbing organic molecules may cause aggregation.

  A method for removing moisture is not particularly limited, and examples thereof include heating, decompression, and humidity control. For example, when heating in an electric furnace, the heating temperature is preferably 100 ° C. or higher and 300 ° C. or lower. If it is this temperature, the water | moisture content on a board | substrate surface will evaporate and there will be no influence on a base material. The heating time is preferably 1 hour or longer. Below 100 ° C., the adsorbed water evaporates, but its speed is slow and needs to be maintained for a long time, which is not economical. Above 300 ° C, the microporous structure formed by anodic oxidation may cause some cracks due to thermal oxidation. In addition, reducing the pressure or heating in dry air is also a means for promoting dehydration. Other than heating, there is a method of removing surface adsorbed water in the micropores by depressurization with a vacuum dryer, oxygen plasma cleaning, ozone plasma cleaning, or vacuum ultraviolet light irradiation. The method using plasma cleaning or vacuum ultraviolet light not only removes moisture on the surface, but also is advantageous in the formation of a more uniform organic molecular intermediate layer because it decomposes organic substances adhering to the surface and generates surface hydroxyl groups. .

<Formation method of organic molecular intermediate layer>
The method for forming the organic molecular intermediate layer is not particularly limited, and there are two methods, a liquid phase method and a gas phase method. For example, in the liquid phase method, the substrate can be formed by immersing it in an organic solvent in which the adsorptive organic molecules are dissolved. Furthermore, after immersion, in order to make a base material react with an unreacted adsorptive organic molecule, it may heat. On the other hand, in the vapor phase method, for example, there is a method in which an adsorbing organic molecule and a metal substrate are placed in a closed container and heated for a predetermined time to react the vaporized adsorbing organic molecule with the substrate. In both the liquid phase method and the gas phase method, the hydroxyl group on the substrate surface reacts with the adsorbing organic molecules, and the adsorbing organic molecules self-assemble on the substrate surface to form an organic molecular layer. At this time, the organic molecular film to be formed is easily affected by moisture. This is because the adsorptive organic molecules are hydrolyzed by a small amount of water, and the adsorbing organic molecules self-condense with each other. To form a uniform organic molecule intermediate layer, only water removal of the metal material is required. In addition, it is desirable to use a dehydrated organic solvent in the liquid phase method or to keep the inside of the sealed container at a low humidity in the gas phase method under conditions where the amount of water in the reaction field is controlled. . It is important to manage moisture until the organic molecular intermediate layer is formed on the surface of the microporous structure.

<Method for forming fluorine-based lubricant layer>
The formation method of the fluorine-based lubricant layer is not particularly limited, but it may be supported on the surface of the base material by applying the fluorine-based lubricant to the surface of the fine pore structure on which the organic molecular intermediate layer is formed. If the surface tension on the surface of the metal material is reduced by the organic molecular intermediate layer, the fluorine-based lubricant can easily penetrate into the surface of the microporous structure by capillary action. Examples of methods for applying to the entire surface of the base material include using a bar coater, roll coater, and brush, including techniques such as dropping a fluorine-based lubricant onto a substrate and immersing a metal material in the fluorine-based lubricant. Techniques. When the fluorine-based lubricant has a high viscosity and it is difficult for the lubricant to permeate the entire surface of the substrate, it is also effective to promote the permeation of the fluorine-based lubricant into the micropores by reducing the pressure.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

<Type of metal plate>
Metal materials include aluminum plate (purity 99.99%, 300 μm thickness), titanium plate (purity 99.5%, 500 μm thickness), iron plate (purity 99.99%, 200 μm thickness), stainless steel plate (SUS304, SUS430, 50 μm thickness) ) Was used after ultrasonic degreasing treatment in acetone.

<Preparation method of micropore structure>
Micropores were formed on the surface of the metal material by anodic oxidation (porous formation) or electrolytic etching, and a platinum plate was used as the counter electrode (cathode).
In the case of anodizing, the aluminum plate is subjected to constant voltage electrolysis in the range of 10-200 V in a 0.3 mol dm ^-3 oxalic acid aqueous solution at 15 ° C or in a 0.3 mol dm ^-3 phosphoric acid aqueous solution at 15 ° C. A fine pore structure of oxide was formed on the surface. Thereafter, the pore size was controlled by immersing and chemically dissolving the metal material in a 5 wt% phosphoric acid aqueous solution at 30 ° C. In the case of electrolytic etching, a constant current of 0.2 A cm ^-2 in a mixed solution of hydrochloric acid (0.23 mol dm ^-3 ), sulfuric acid (1.88 mol dm ^-3 ) and aluminum ion (0.37 mol dm ^-3 ) at 80 ° C. Electrolysis was performed to form a microporous structure on the substrate surface.
The titanium plate was subjected to constant potential electrolysis in a range of 3-120 V in a glycerin solution containing 0.6 mol dm ^-3 potassium hydrogen phosphate and 0.2 mol dm ^-3 potassium phosphate at 160 ° C.
The iron plate was subjected to constant potential electrolysis in the range of 10-150 V by adding water in the range of 0.1-0.5 mol dm ^-3 in an ethylene glycol solution containing 0.1 mol dm ^-3 ammonium fluoride at 20 ° C. .
The stainless steel plate was subjected to constant potential electrolysis in the range of 0.1 to 0.5 mol dm ⁻³ in an ethylene glycol solution containing 0.1 mol dm ⁻³ ammonium fluoride and in the range of 10 to 150 V.
The electrolyzed aluminum plate, titanium plate, iron plate, and stainless steel plate were immediately washed with water and dried.

<Determination of pore diameter, pore length, porosity>
The pore diameter, pore length, and porosity of the fine pore structure were measured with a scanning electron microscope (JEOL, JSM-6500F), and measured with a surface or cross-sectional observation of 1000 to 50,000 times. As the pore diameter of the fine pore structure formed by anodization, the average value of pore diameters measured in nm units was calculated for 20 or more pores observed in an arbitrary field of view in surface SEM observation. The pore length was obtained by calculating the average value of pore lengths measured in nm units for 20 or more pores observed in an arbitrary field of view in cross-sectional SEM observation, and rounding off to the first digit. The porosity was calculated from the average value of the area occupied by the micropores per field, which was measured in 10 arbitrary fields during surface SEM observation. For the pore diameter of the micropore structure formed by electrolytic etching, an average value of pore diameters measured in nm units for 100 or more pores observed in an arbitrary field of view in surface SEM observation was calculated. The pore length was obtained by calculating the average value of pore lengths measured in nm units for 100 or more pores observed in an arbitrary field of view in cross-sectional SEM observation, and rounding off to the first digit. The porosity was calculated from the average value of the area occupied by the micropores per field, which was measured in 10 arbitrary fields during surface SEM observation.

<Moisture removal from substrate>
The metal material with a microporous structure was heated at 80, 100, 200, 300, 350 ° C for 1 hour in air or nitrogen (dew point -70 ° C or less, flow rate 5 L / min) atmosphere to remove moisture. .
Alternatively, a plasma cleaner (manufactured by Harrick Plasma, PDC-32G) was used for 1 minute or longer, and then plasma cleaning was performed for 5 minutes.

<Formation of organic molecular interlayer>
The organic molecule intermediate layer was formed by immersing the metal material for one day in a dehydrated ethanol solution in which the adsorbing organic molecules were dissolved. Adsorbable organic molecules include n-dodecylphosphonic acid, 1H, 1H ', 2H, 2H'-perfluorodecyl-1-phosphonic acid, 1H, 1H', 2H, 2H'-perfluorodecyl phosphate, 1H, 1H ', 2H, 2H' Each of -perfluorododecyl-1-phosphonic acid was dissolved in a dehydrated ethanol solution at a concentration of 1 wt%. After immersion, it was washed with dehydrated ethanol and dried with warm air. For comparison, the metal material similarly heat-dried was also immersed in a hexane solution in which 1 wt% of n-octyltriethoxysilane was dissolved for one day. After immersion, the substrate was washed with hexane and then heat-treated at 150 ° C. for 1 hour in a drying furnace to remove the remaining solvent.

<Formation of fluorine-based lubricant layer>
For the fluorine-based lubricant layer, commercially available fluorine-based solvents such as Krytox 100 and Krytox 103 manufactured by DuPont, or Fluorinert FC-70 and FC-43 manufactured by 3M were used. A small amount of the fluorine-based lubricant was dropped on the surface of a metal material having a fine pore structure in which an organic molecular intermediate layer was formed with a micropipette, and then spread over the entire surface of the sample with a brush.

<Precipitation of aggregates by self-condensation of adsorptive organic molecules>
In order to investigate the precipitation of aggregates due to self-condensation of adsorptive organic molecules in the formation of the organic molecular intermediate layer, evaluation test 1 was conducted. When aggregates are deposited, it is known that a white pattern is generated on the surface of the metal material on which the organic molecule intermediate layer is formed. Whether or not moisture is removed from the metal material having micropores, and the type of adsorptive organic molecules (Table 1) evaluated the effect of sucrose on the formation of organic molecular interlayers. As a result, when the adsorptive organic molecule that forms the organic molecule intermediate layer is organosilane, even if it is chemically adsorbed on the surface of the metal material having micropores, a white pattern is observed on the surface, and the aggregate of the organosilane molecule is a metal Produced on the material (Experiment No. 1-7). In addition, even when the adsorptive organic molecule is an organic phosphonic acid, a white pattern was confirmed on a part of the surface when the appropriate substrate drying treatment was not performed (Experiment No. 8-14) ( (Figure 3). On the other hand, when water is removed from a metal material with fine pores by drying in a dry nitrogen atmosphere or at 100-300 ° C in the air, white patterns are observed by visual observation even if adsorbing organic molecules are formed. (Experiment No. 15-21, 25-30, 34-36) (FIG. 4). However, when the heating temperature was less than 100 ° C., a white pattern was observed, and when the heating temperature exceeded 300 ° C., cracks were sometimes observed in the film. (Experiment No. 22-24, 31-33). In addition to removing moisture by heat drying, even when the substrate having micropores was processed by plasma cleaning, no white pattern was observed on the surface when the organic molecular intermediate layer was formed (Experiment No. 37- 39). However, the effect of generating surface hydroxyl groups by plasma cleaning could not be confirmed in this evaluation test. From the above, if organic alkyl molecules having phosphorus functional groups are used as the adsorbing organic molecules and the metal material having fine pores is appropriately dried, the generation of aggregates can be suppressed and the organic molecule intermediate layer can be suppressed. It was found that can be formed.

<About self-healing and sustainability>
Table 2 shows the self-healing properties and sustainability of metal materials in which organic molecular interlayers are formed under conditions that allow organic molecular interlayers to form without agglomeration in Evaluation Test 1 and then a fluorine-based lubricant layer is formed. Therefore, the results of the evaluation tests 2 to 4 are shown. Here, the evaluation test 2 is for confirming the self-repairing property when a cutting knife is cut with a cutter knife into a metal material holding a fluorine-based lubricant layer on a fine hole through an organic molecular intermediate layer. If self-healing properties are manifested, the water and oil repellency is maintained by the penetration of the fluorine-based lubricant into the buttocks. Evaluation test 3 confirms self-healing properties in the same way as evaluation test 2, but the self-healing properties were investigated under conditions more severe than evaluation test 2 by increasing the area of the buttocks by the wear test. Is. Evaluation test 4 was conducted to investigate the dissipation and evaporation of the fluorine-based lubricant layer when a metal material was immersed in high-temperature water in order to confirm the durability of the water / oil repellent effect.

  From Table 2, when the pore diameter of the micropore is 10 nm or more and 300 nm or less and the pore length is 100 nm or more, the scores for the evaluation tests 2 to 4 are all 2 or more (Experiment No. 41-42, 44 -47). In particular, when the pore diameter of the fine pore structure was 50 nm or more and 300 nm or less, the score was 3 for water droplets in Evaluation Test 2. However, even if the pore diameter was 50 nm or more, when the pore length was 100 nm or less, the scores for evaluation tests 3 and 4 were both 1 (experiment No. 43). In addition, evaluation tests 3 and 4 were rated 1 even when the pore diameter was 10 nm or less (Experiment No. 40), and evaluation tests 2 and 3 were rated 2 or more when the pore diameter was more than 300 nm. Then, it was rated 1 for oil droplets (Experiment No. 48). This tendency was observed when the microporous structure was formed by electrolytic etching instead of anodic oxidation (Experiment No. 49), and the same tendency was observed when the metal substrate was an iron-based metal or titanium (Experiment No. 50-61). Fluorine-based lubricants were confirmed to be self-healing and durable even in perfluoroamines, perfluorocarbons, and perfluoroethers with different viscosities and volatility (Experiment No. 62-70).

  In addition, when the pore length exceeds 1 μm, the score of evaluation test 2 is 4 or more, and when the porosity is 10% or more and 40% or less, the score for water droplets in evaluation test 3 is 4 or more (experimental). No.71-77). This is because the porosity is in the proper range and the pore length increases, so that the amount of fluorine-based lubricant retained on the surface of the base material has increased, and even if wrinkles occur, micropores remain in the lower part. This is presumed to be due to high self-healing properties.

  When the porosity was 10% or more and 40% or less and the pore length was less than 1 μm, the score for water drops in Evaluation Test 2 and Evaluation Test 3 was 3 or more (Experiment No. 79-82). Furthermore, when the porosity is 20% or more and 30% or less, the score for rapeseed oil in Evaluation Test 3 is 3 or more, and the score in Evaluation Test 3 is higher than when the porosity is less than 10% and more than 40%. (Experiment No. 80-81). In this range of porosity, the amount of fluorine-based lubricant on the base material increases while maintaining the strength of the base material, so that repair by oozing out of the fluorine-based lubricant to the buttocks was easily performed. It is estimated to be.

<Adsorptive organic molecules forming the organic molecular interlayer>
Table 3 shows the results when fluorinated organic phosphonic acid or phosphoric acid is used as the adsorptive organic molecule forming the organic molecular interlayer. Since the organic molecular intermediate layer was fluorinated, the score in Evaluation Test 4 was 4 or more (Experiment No. 84-92). This is presumably because the retention of the fluorine-based lubricant increased due to an increase in the physical interaction with the fluorine-based lubricant layer. In addition, when the fluorine-based lubricant forming the fluorine-based lubricant layer is a perfluoroalkyl ether having lower volatility, the scores in the evaluation test 4 are all 5. This is thought to be due to a decrease in loss due to dissipation and evaporation of the fluorine-based lubricant.

<Method and Evaluation Method of Evaluation Test 1> (Table 1)
Evaluation test 1 is an investigation of the precipitation of aggregates due to self-condensation of adsorptive organic molecules in the formation of an organic molecule intermediate layer. When aggregates are deposited, a white pattern is formed on the surface of the metal material on which the organic molecule intermediate layer is formed. About the influence of the presence or absence of moisture removal on the metal material with micropores and the type of adsorbing organic molecules investigated. The presence or absence of aggregates was evaluated by visually observing the surface of the metal material on which the organic molecular intermediate layer was formed. Score 3 was accepted.
Score 3: No spotted pattern on the substrate surface Score 2: Spotted pattern appears on the substrate surface Score 1: Spotted pattern appears on the entire surface

<Method and judgment method of evaluation test 2> (Tables 2 and 3)
In the evaluation test 2, in order to confirm the self-healing property of the metal material holding the fluorine-based lubricant layer on the micropores having a pore length of 1 μm or more and 50 μm or less via an organic molecular intermediate layer, a scissor flaw is used. The water and oil repellency when put in was investigated. In evaluation test 2, a grid-like cut was made on a metal material surface with a cutter knife at a 1 mm square interval and a cut depth in the range of about 0.001 mm to 0.005 mm, and then water or rapeseed oil was micropipetted on the cut. 10 μL was added dropwise. Then, using a contact angle meter (Kyowa Interface Chemical Co., Ltd., DM-301), tilt the metal material by 1 degree with respect to the horizontal direction, measure the angle when the droplet starts to move on the metal material surface, The self-healing property of the water and oil repellency of the produced material was evaluated. A score of 2 or higher was accepted.
Score 5: 5 ° or less Score 4: Over 5 °, 10 ° or less Score 3: Over 10 °, 20 ° or less Score 2: Over 20 °, 45 ° or less Score 1: Over 45 °

<Method and evaluation method of Evaluation Test 3> (Tables 2 and 3)
Evaluation test 3 is a sliding test to confirm the self-healing property of the metal material holding the fluorine-based lubricant layer on the micropores with a porosity of 10% or more and 40% or less via the organic molecular intermediate layer. The self-healing property was investigated under conditions more severe than those in the evaluation test 2 by increasing the area of the buttocks. Evaluation test 3 uses a wear tester (CSM, TRB-S-DU-0000) on a metal material surface, SUS304 ball, ball size 6 mmφ, load 1 N, travel distance 5 m, 10 mm s ^{− The} metal material surface was worn by reciprocating at a speed of ¹ for 500 seconds, and then 10 μL of water or rapeseed oil was dropped onto the worn part with a micropipette. Then, using a contact angle meter (Kyowa Interface Chemical Co., Ltd., DM-301), tilt the metal material by 1 degree with respect to the horizontal direction, measure the angle when the droplet starts to move on the metal material surface, The self-healing property of the water and oil repellency of the produced material was evaluated. A score of 2 or higher was accepted.
Score 5: 5 ° or less Score 4: Over 5 °, 10 ° or less Score 3: Over 10 °, 20 ° or less Score 2: Over 20 °, 45 ° or less Score 1: Over 45 °

<Method and judgment method of evaluation test 4> (Tables 2 and 3)
Evaluation test 4 is a water repellent when immersed in high-temperature water in order to confirm the durability of the metal material holding the fluorine-based lubricant layer on the micropores through the organic molecular interlayer of various materials. The oil repellency was investigated. In evaluation test 4, the surface of the metal material was immersed in water heated to 50 ° C. for 5 minutes, and then 10 μL of water or rapeseed oil was dropped on the metal material with a micropipette. Then, using a contact angle meter (Kyowa Interface Chemical Co., Ltd., DM-301), tilt the metal material by 1 degree with respect to the horizontal direction, and measure the angle when the droplet starts to move on the metal material surface. Then, the sustainability of the water / oil repellency of the produced material was evaluated. A score of 2 or higher was accepted.
Score 5: 5 ° or less Score 4: Over 5 °, 10 ° or less Score 3: Over 10 °, 20 ° or less Score 2: Over 20 °, 45 ° or less Score 1: Over 45 °

Claims (5)

A composite material having a fine lubricant and a fluorine-based lubricant layer through an organic molecular intermediate layer on the surface of a metal material that does not contain moisture, and the pore diameter of the fine pore is 10 nm or more and 300 nm or less and hole length is at 100 nm or more, and the organic molecule intermediate layer has a fluoroalkyl chain or an alkyl chain, of the absorptive organic molecules with phosphonic acid group or phosphoric acid group at one end, the phosphonic acid a layer and the base or the surface of the metal material having the fine pores and the phosphate group is formed by reaction and the fluorine-based lubricant layer is in the perfluoroalkyl ether or perfluoroalkyl amine or a perfluorocarbon A composite material characterized by being.   2. The composite material according to claim 1, wherein the pore length of the micropore is 1 μm or more and 50 μm or less. Composite material according to the any of claims 1-2 porosity is 10% to 40% of a metal material having fine pores. Absorptive organic molecule forming organic molecule intermediate layer is a composite material according to claim 1 having a fluoroalkyl chain having 6 or more carbon atoms which have a phosphonic acid group or phosphoric acid group. Micropores are formed on the surface of the metal material, and after removing moisture on the surface of the metal material by heating and drying at 100 ° C. or more and 300 ° C. or less in air or a dry gas atmosphere, it has a phosphonic acid group or a phosphoric acid group . An alkyl molecule or a fluoroalkyl molecule is formed on the surface of the metal material via the phosphonic acid group or the phosphoric acid group , and further comprises perfluoroalkyl ether, perfluoroalkylamine, or perfluoroalkylcarbon. A method for producing a composite material in which a fluorine-based lubricant is coated on the metal material.