Multilayer film

Abstract

[Problem] To provide a film which exhibits both good water repellency and good oil repellency, while maintaining adhesion to a resin base film. [Solution] A multilayer film which comprises a coating layer on a resin base film, said coating layer containing a binder resin and fine particles that have hydrophobized surfaces, wherein if the thickness of the coating layer is divided into 100 equal parts, and the interface between the resin base film and the coating layer is taken as 0, while the outermost surface of the coating layer is taken as 100, the fine particles that have hydrophobized surfaces are unevenly distributed in the parts 30 to 100.

Description

Technical Field

[0001] The present invention relates to a laminated film. More specifically, it relates to a coated laminated film having water and oil repellency.

Background Art

[0002] Materials that exhibit water and oil repellency on the surface are industrially important in fields where antifouling properties are required. To achieve antifouling properties, it is necessary to reduce the interaction between contaminants and the material surface, and generally, this is usually achieved by making the material surface water-repellent or oil-repellent.

[0003] Conventionally, methods for producing films with excellent water and oil repellency by using silica fine particles having voids or by using fine particles having voids by forming aggregates are known (see, for example, Patent Documents 1 and 2). However, generally, coating methods for imparting water and oil repellency to the film surface have a problem that the adhesiveness to the substrate is low and the coating layer easily peels off, and it has been difficult to achieve both sufficient water and oil repellency and adhesion to the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] The present invention has been made in view of such problems of the prior art. That is, an object of the present invention is to provide a film that exhibits good physical properties in both water repellency and oil repellency while maintaining adhesion to a resin substrate film. [[ID=Z41]]

Means for Solving the Problems

[0006] As a result of intensive studies to achieve such an object, the present inventors have found that the above problems can be solved by the means shown below, and have reached the present invention. That is, the present invention comprises the following configurations. 1. A laminated film having a coating layer containing a binder resin and fine particles whose surfaces are hydrophobized on a resin base film, wherein the thickness of the coating layer is divided into one hundred equal parts, and when the interface between the resin base film and the coating layer is 0 and the outermost surface of the coating layer is 100, the laminated film in which the fine particles whose surfaces are hydrophobized are unevenly distributed only in the 30 to 100 parts. 2. The laminated film according to the first item above, wherein the resin base film is a polyethylene terephthalate film or a polyethylene naphthalate film. 3. The laminated film according to the first or second item above, wherein the average primary particle diameter of the fine particles whose surfaces are hydrophobized is 30 nm to 1 μm. 4. The laminated film according to any one of the first to third items above, wherein the binder resin is an acid-modified polyolefin resin or a polyester resin.

Effect of the Invention

[0007] The laminated film of the present invention shows high water and oil repellency by unevenly distributing many fine particles having hydrophobized surfaces on the surface side of the coating layer, and shows adhesion between the coating layer and the resin base film.

Mode for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in detail. The present invention provides a laminated film having excellent water and oil repellency on the surface of the coating layer and adhesion between the coating layer and the resin base film.

[0009] (Resin Base Film) The laminated film in the present invention has a resin base film. The material of this resin base film is not particularly limited, but a resin film is preferable from the viewpoint of handleability such as flexibility. Examples of the resin constituting the resin film include polyolefins such as polyethylene, polypropylene, polystyrene, and diene polymers; polyesters such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 6,6, nylon 6,10, and nylon 12; acrylate resins such as polymethyl methacrylate, polymethacrylic acid esters, polymethyl acrylate, and polyacrylic acid esters; polyacrylic acid resins, polymethacrylic acid resins, polyurethane resins, cellulose resins such as cellulose acetate and ethyl cellulose; aromatic hydrocarbon polymers such as polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyimide, polyamideimide, polybenzimidazole, polybenzoxazole, and polybenzothiazole; fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride; epoxy resins, phenol resins, novolak resins, benzoxazine resins, and the like. Among these, from the viewpoints of transparency and dimensional stability, a film made of a polyester resin or an acrylate resin is preferable. Specific examples of the polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among these, from the viewpoint of physical properties, polyethylene terephthalate and polyethylene naphthalate are preferable, and from the viewpoint of the balance between physical properties and cost, polyethylene terephthalate is particularly preferable.

[0010] The resin base film may be a single layer or may have two or more layers laminated. When two or more layers are laminated, the same or different films can be laminated. Also, a resin composition may be laminated on the resin base film. Furthermore, within the range where the effects of the present invention are achieved, various additives can be contained in the resin base film as necessary. Examples of the additives include antioxidants, light-resistant agents, anti-gelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, and the like. When the resin base film is composed of two or more layers, additives can also be contained according to the functions of each layer. In order to improve the handling properties such as the slipperiness and winding property of the resin base film, inert particles may be contained in the resin base film.

[0011] In the present invention, the thickness of the resin base film is not particularly limited, but it is preferably 5 μm or more and 300 μm or less. More preferably, it is 10 μm or more and 280 μm or less, and even more preferably, it is 12 μm or more and 260 μm or less. When it is 5 μm or more, it is easy to coat during the lamination of the coating layer, and when it is 300 μm or less, it is advantageous in terms of cost.

[0012] As the surface of the resin base film, it may be used untreated, but those subjected to surface treatments such as plasma treatment, corona treatment, flame treatment, or those coated with a primer layer can also be used.

[0013] (Fine particles with a hydrophobized surface) The laminated film in the present invention has a coating layer directly on the resin base film or via another layer, and the coating layer contains fine particles with a hydrophobized surface. The type of the fine particles is not particularly limited. For example, at least one of silica (silicon dioxide), alumina, titania, zirconia, etc. can be used. These may be synthesized via any compound, or known or commercially available ones may be used. In particular, silica (silicon dioxide) fine particles are preferable because the surface hydrophobization described later is easy.

[0014] The microparticles have a hydrophobized surface, but the method of hydrophobization is not particularly limited. For example, they may be those obtained by hydrophobizing hydrophilic oxide microparticles by surface treatment. That is, the surface of the hydrophilic oxide microparticles can be treated with an arbitrary reagent such as a silane coupling agent, and those with hydrophobized surfaces can be used.

[0015] As the method for hydrophobizing microparticles typified by silica microparticles, surface treatment with various known reagents such as silicone oil, silane coupling agents, and silazanes is preferably used. In particular, from the viewpoint of exhibiting excellent water and oil repellency, a fluorine-based functional group typified by a 1H,1H,2H,2H-perfluorooctyl group, 1H,1H,2H,2H-perfluorodecyl group, 1H,1H,2H,2H-perfluorohexyl group, 3,3,3-trifluoropropyl group, etc., an alkyl group typified by a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, octyl group, etc., an alkenyl group, an alkynyl group, a vinyl group, a cyclohexyl group, a styryl group, a phenyl group, a trimethylsilyl group, etc. are more preferably introduced. Among these, hydrophobic oxide microparticles having a trimethylsilyl group introduced are preferred, and hydrophobic silica having a trimethylsilyl group introduced is particularly preferred because they exhibit more excellent water and oil repellency.

[0016] The primary particle diameter of the fine particles in the present invention is preferably 5 nm or more and 2 μm or less, more preferably 20 nm or more and 1.5 μm or less, and even more preferably 30 nm or more and 1 μm or less. When it is 5 nm or more, it becomes easy to form irregularities on the surface layer of the coating layer, and it is preferable because it is easy to increase the contact angle described later. On the other hand, when it is 2 μm or less, it is preferable because it is difficult for the fine particles to fall off from the coating layer, and it is also preferable because it is easy to maintain the transparency of the resin base film. In the present invention, the size of the primary particle average diameter can be determined from the results of morphological observation by a microscope using a scanning electron microscope, a transmission electron microscope, or the like. Specifically, in these microscopic observations, the average of the diameters of 20 arbitrarily selected fine particles is taken as the primary particle average diameter. The primary particle average diameter of amorphous fine particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the area of the observed fine particles by π, calculating the square root, and multiplying by 2.

[0017] In the present invention, as an index of the modification rate by the functional group having water / oil repellency on the surface of the fine particles whose surface is hydrophobized, the measurement result by an X-ray photoelectron spectrometer (ESCA) can be used. Specifically, the atomic composition ratio can be determined for a depth region of about 10 nm, and comparison can be made for the ratio of a specific atom constituting the functional group having water / oil repellency, for example, a carbon atom. In the present invention, from the viewpoint of exhibiting excellent water / oil repellency, for example, in the case of hydrophobic silica into which a trimethylsilyl group is introduced, the ratio of carbon atoms is preferably 8 at% or more.

[0018] (Binder resin) The binder resin in the present invention is not particularly limited as long as it can be well adhered to the resin base film. For example, it is preferable to use a polyester resin, an acid-modified polyolefin resin, a polyurethane resin, an epoxy resin, an acrylic resin, etc. Further, from the viewpoint of adhesion to the resin base film, it is preferable to use a polyester resin or an acid-modified polyolefin resin for the first coating layer, and it is particularly preferable to use a polyester resin, an acid-modified polyolefin resin, or an acrylic silicone resin for the second coating layer from the viewpoint of preventing a decrease in water and oil repellency.

[0019] As the acid-modified polyolefin resin, those in which at least a part is a polyolefin or an unsaturated carboxylic acid-modified polyolefin are preferable, more preferably unsaturated carboxylic acid-modified polypropylene or unsaturated carboxylic acid-modified polyethylene, and most preferably unsaturated carboxylic acid-modified polypropylene.

[0020] As the unsaturated carboxylic acid, maleic acid, fumaric acid, acrylic acid, methacrylic acid, and acid anhydrides thereof are preferable, and maleic anhydride and maleic acid are most preferable. It can be said that a coating layer having high adhesion to the resin base film can be formed by these.

[0021] The acid value of the acid-modified polyolefin resin is preferably 2 mgKOH / g or more and 35 mgKOH / g or less, more preferably 5 mgKOH / g or more and 35 mgKOH / g or less, and still more preferably 5 mgKOH / g or more and 25 mgKOH / g or less. When the acid value of the acid-modified polyolefin resin is 2 mgKOH / g or more, the adhesion to the resin or the resin base film is good, and when the acid value is 35 mgKOH / g or less, the water and oil repellency of the resin itself is utilized for the liquid repellency of the coating layer, which is preferable. [[ID=%13]]

[0022] The polyester resin used as the binder resin of the coating layer is not particularly limited, but polyester resins of the BYRON (registered trademark) series manufactured by Toyobo Co., Ltd. are preferably used.

[0023] The binder resin may be used after being mixed with a curing agent to crosslink it, and the curing agent used is preferably an isocyanate-based compound, an epoxy-based compound, a melamine-based compound, or a carboxylic acid, more preferably an epoxy-based compound or a melamine-based compound, which makes it possible to form a coating layer containing silica fine particles while maintaining the transparency of the resin substrate film.

[0024] (Other components in the coating layer) The coating layer of the present invention may contain components other than the above-mentioned fine particles, such as binder components, antioxidants, curing agents, light resistance agents, antigelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, etc., and these components can be appropriately contained as needed.

[0025] (Coating layer structure) In the present invention, when the thickness of the coating layer is divided into 100, with the interface between the resin substrate film and the coating layer being 0 and the outermost surface of the coating layer being 100, it is preferable that the fine particles with hydrophobic surfaces are unevenly distributed only in the portion from 30 to 100. The portion is more preferably 40 or more, and even more preferably 50 or more. A portion of 30 or more is preferable because it improves the adhesion between the coating layer and the resin substrate film.

[0026] Dividing the thickness of a coating layer into 100 equal parts, with the interface between the resin substrate film and the coating layer as 0 and the outermost surface of the coating layer as 100, the method for distributing the hydrophobic surface particles only in the 30-100 part is not particularly limited, but examples include providing a coating layer (hereinafter referred to as the first coating layer) without hydrophobic surface particles on the resin substrate film directly or via another layer, and then laminating a coating layer (hereinafter referred to as the second coating layer) with hydrophobic surface particles on the first coating layer, and adjusting the sum of the thicknesses of the other layers and the first coating layer to be 30% or more of the total coating layer thickness. While the upper limit of the 30-100 part is of course 100, the lower limit is preferably 90 or less, and more preferably 80 or less, to prevent the hydrophobic surface particles from falling off.

[0027] Incidentally, the thickness of the entire coating layer is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 30 nm or more, and particularly preferably 50 nm or more from the viewpoint of satisfying the adhesion between the coating layer and the resin base film. Further, the thickness of the entire coating layer is preferably 3 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less, and particularly preferably 1.2 μm or less in consideration of water and oil repellency on the surface of the coating layer, economy, etc.

[0028] The solid content of the coating liquid is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and still more preferably 3% by mass or more and 10% by mass or less. Being within the above range is preferable because the unevenness of the fine particles is likely to appear on the coating surface layer and the coatability is also good.

[0029] The range of the mixing ratio of the fine particles to the binder resin (binder resin: fine particles) is preferably 90:10 to 5:95, more preferably 70:30 to 5:95, and still more preferably 50:50 to 5:95. Being within the above range is preferable because the unevenness of the fine particles appears on the surface but a state where the fine particles are less likely to fall off from the binder can be formed.

[0030] (Solvent) The solvent used for coating is not particularly limited. For example, organic solvents such as water, alcohols, ketones, normal hexane, cyclohexane, toluene, butyl acetate, and glycols are preferable, organic solvents such as toluene, cyclohexane, and hexane are more preferable, and toluene is most preferable. With these, the solubility of the binder resin is high and a uniform coating liquid can be prepared.

[0031] (Primary particle diameter of fine particles with hydrophobized surface) It can be determined from the results of morphological observation by a microscope using a scanning electron microscope, a transmission electron microscope, or the like. Specifically, the average diameter of 20 randomly selected particles in these microscope observations is defined as the primary particle average diameter.

[0032] (Method for measuring acid value) The acid value (mgKOH / g-resin) in the present invention is the amount of KOH required to neutralize 1 g of acid-modified polyolefin, and was measured according to the test method of JIS K0070 (1992). Specifically, after dissolving 1 g of acid-modified polyolefin in 100 g of xylene whose temperature was adjusted to 100 °C, titration was performed with a 0.1 mol / L potassium hydroxide ethanol solution [trade name “0.1 mol / L ethanolic potassium hydroxide solution”, manufactured by Wako Pure Chemical Industries, Ltd.] using phenolphthalein as an indicator at the same temperature. At this time, the amount of potassium hydroxide required for titration was converted to mg to calculate the acid value (mgKOH / g).

[0033] (Water and oil repellency) The water and oil repellency of the laminated film according to the present invention can be evaluated by known methods. Specifically, the water repellency can be evaluated by measuring the contact angle using water, and the oil repellency can be evaluated by measuring the contact angle using iodine methane. The preferable range of the contact angle with respect to water in the present invention is 100 degrees or more, more preferably 120 degrees or more. The larger the contact angle with respect to water, the better, and the upper limit is not particularly limited, but in reality, it is about 170 degrees. When the contact angle with respect to water is 100 degrees or more, it is preferable because it exhibits excellent water repellency. When it is 120 degrees or more, it is more preferable because it exhibits water repellency equal to or higher than that of conventional fluororesin sheets typified by polytetrafluoroethylene (PTFE). Further, the preferable range of the contact angle of iodine methane in the present invention is 60 degrees or more, more preferably 90 degrees or more. The larger the contact angle of iodine methane, the better, and the upper limit is not particularly limited, but in reality, it is about 160 degrees. When the contact angle of iodine methane is 60 degrees or more, it is preferable from the viewpoint that it can impart oil repellency capable of suppressing oil stains and the like. When it is 90 degrees or more, it is more preferable because it exhibits oil repellency equal to or higher than that of conventional fluororesin sheets.

[0034] (Manufacturing process of laminated film) In the production of the laminated film of the present invention, the coating method is not particularly limited. For example, it can be produced according to known methods such as roll coating, gravure coating, bar coating, doctor blade coating, spin coating, spray coating, and brush coating. The solvent used when coating by these methods is not particularly limited, and for example, water, alcohols, ketones, normal hexane, cyclohexane, toluene, butyl acetate, organic solvents such as glycols can be appropriately selected and used. These solvents may be used alone or in combination of a plurality. The content of the fine particles whose surface is hydrophobized with respect to the solvent can be selected at any ratio that can obtain a uniform dispersion. The method of drying after coating may be either natural drying or heat drying, but from the viewpoint of industrial production, heat drying is more preferable. The drying temperature is not particularly limited as long as it does not affect the components contained in the resin base film or the coating layer, but usually 150 ° C or lower is preferable, and 50 ° C or higher and 140 ° C or lower is more preferable. The drying method is not particularly limited, and known methods for drying the film such as a hot plate or a hot air oven can be used. The drying time is appropriately selected according to other conditions such as the drying temperature, but it may be within a range that does not affect the components contained in the resin base film or the coating layer. Further, the coating step may be a so-called offline coating method in which it is performed in a separate step after the formation of the resin base film, or a so-called inline coating method in which a coating liquid is applied to an unstretched sheet or a uniaxially stretched film in the production process of the resin base film and stretched at least in one axial direction.

Example

[0035] Hereinafter, the present invention will be further described with specific examples, but the present invention is not limited to the aspects of these examples. First, the evaluation method adopted in the present invention will be described.

[0036] (Contact angle measurement) The contact angle with respect to the solvent was measured for the surface of the coating layer of the fabricated laminated film. For the contact angle measurement, a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd. was used. Pure water and diiodomethane were used as the measurement solvents. The contact angle of water (hereinafter sometimes abbreviated as WCA) was measured 10 seconds after dropping 1.8 μL of water droplets. The contact angle of diiodomethane (hereinafter sometimes abbreviated as DCA) was measured 10 seconds after dropping 0.9 μL of diiodomethane droplets.

[0037] (Adhesion measurement) The adhesion between the film and the coating layer was determined by a visual test using cellophane tape. A cellophane tape with a width of 24 mm was attached to the coating surface, strongly pressed with a finger, and then the presence or absence of peeling of the coating layer was visually confirmed when it was peeled off forcefully.

[0038] (Measurement of the average primary particle diameter) The average primary particle diameter of the hydrophobicized fine particles was determined from the results of observations using a scanning electron microscope or a transmission electron microscope. Specifically, the average of the diameters of 20 randomly selected fine particles in these microscope observations was taken as the average primary particle diameter. The average primary particle diameter of amorphous fine particles can be calculated as the equivalent circular diameter. The equivalent circular diameter is a value obtained by dividing the area of the observed fine particles by π, calculating the square root, and doubling the result.

[0039] (ESCA measurement of hydrophobicized fine particles) A dispersion of hydrophobicized fine particles was dropped onto a clean aluminum foil, dried, and a thin film of hydrophobicized fine particles was formed on the aluminum foil. At this time, it was dried promptly so as not to cause surface contamination as much as possible, and sampled immediately for surface composition analysis. The apparatus used was K-Alpha [[ID=2l]] + (manufactured by Thermo Fisher Scientific). The details of the measurement conditions are shown below. In addition, background removal was performed by the Shirley method during the analysis. The surface composition ratio was taken as the average value of the measurement results at three or more sites where Al of the resin base film was not detected. ·Measurement conditions Excitation X-ray: Monochromatized AlKα ray X-ray output: 12 kV, 6 mA Photoelectron emission angle: 90 degrees Spot size: 400 μmΦ Pass energy: 50 eV Step: 0.1 eV

[0040] The following are the reagents used during the examination of the examples. · BYRON (registered trademark) RV280 (polyester resin manufactured by Toyobo Co., Ltd.) [[ID=I8]]· SIMAC (registered trademark) US-350 (acrylic silicone resin manufactured by Toagosei Co., Ltd., solid content concentration 30% by mass) · MS-001 (methylated melamine resin manufactured by Sanwa Chemical Co., Ltd.) · YD128 (epoxy resin manufactured by Nippon Steel Chemical & Material Co., Ltd.) · TETRAD (registered trademark)-X (polyfunctional epoxy resin manufactured by Mitsubishi Gas Chemical Co., Inc.) · MILLIONATE (registered trademark) MR-001 (isocyanate-based crosslinking agent manufactured by Tosoh Corporation) · KS-1260 (butyltin dilaurate manufactured by Sakai Chemical Industry Co., Ltd.)

[0041] <Production Example of Acid-Modified Polyolefin> To a 1 L autoclave, 100 parts by mass of polypropylene, 150 parts by mass of toluene, 8.5 parts by mass of maleic anhydride, and 4 parts by mass of di-tert-butyl peroxide were added. After heating to 140 °C, the mixture was further stirred for 1 hour. After completion of the reaction, the reaction solution was poured into a large amount of methyl ethyl ketone to precipitate the resin. This resin was further washed several times with methyl ethyl ketone to remove unreacted maleic anhydride. By drying the obtained resin under reduced pressure, maleic anhydride-modified polypropylene (acid value 12.7 mgKOH / g, weight average molecular weight 60,000, Tm 80 °C), which is an acid-modified polyolefin, was obtained.

[0042] <Production Example of Acid-Modified Polyolefin Solution A-1> Weighed 10 parts by mass of the acid-modified polyolefin into a reaction vessel, added 90 parts by mass of toluene thereto, and stirred for 1 hour or more to obtain an acid-modified polyolefin solution A-1 with a solid content concentration of 10% by mass.

[0043] <Production Example of Acid-Modified Polyolefin Solution A-2> Added 23 parts by mass of the acid-modified polyolefin solution A-1, 27 parts by mass of toluene, 0.2 part by mass of YD128 as a crosslinking agent, and 0.02 part by mass of TETRAD (registered trademark)-X as a crosslinking catalyst to a sample bottle, and stirred at room temperature for 5 minutes to obtain an acid-modified polyolefin solution A-2 with a solid content concentration of 5% by mass.

[0044] <Production Example of Polyester Solution B-1> Added 20 parts by mass of BYRON (registered trademark) RV280 (polyester resin manufactured by Toyobo Co., Ltd.), 90 parts by mass of toluene, and 90 parts by mass of methyl ethyl ketone to a sample bottle, and stirred at room temperature for 1 hour to prepare a polyester solution B-1 (solid content concentration: 10% by mass).

[0045] <Production Example of Polyester Solution B-2> Added 23 parts by mass of the polyester solution B-1, 27 parts by mass of toluene, 0.2 part by mass of melamine resin MS-001 as a crosslinking agent, and 0.02 part by mass of p-toluenesulfonic acid (PTS) as a crosslinking catalyst to a sample bottle, and stirred at room temperature for 5 minutes to prepare a polyester solution B-2 (solid content concentration: 5% by mass).

[0046] <Production Example of Silicone Resin Solution C-1> Added 100 parts by volume of CIMAC (registered trademark) US-350, 100 parts by mass of toluene, and 100 parts by mass of methyl ethyl ketone to a sample bottle, and stirred at room temperature for 1 hour to prepare a silicone resin solution C-1 (solid content concentration: 10% by mass).

[0047] <Synthesis Method of Silica Fine Particle Dispersion D-1> 100 parts by mass of tetraethoxysilane and 439 parts by mass of ethanol were mixed in the reaction vessel 1. After mixing 179 parts by mass of ethanol, 13 parts by mass of aqueous ammonia (25%), and 26 parts by mass of deionized water in the reaction vessel 2, the content of the reaction vessel 2 was dropped and transferred to the reaction vessel 1. At this time, in order to prevent a rapid reaction, it was dropped over 10 minutes. After the dropping was completed, the reaction solution was left standing at 20 °C for 48 hours. Then, ammonia and water were distilled off to prepare a silica fine particle dispersion (average primary particle diameter: 35 nm). Then, 150 parts by mass of hexamethyldisilazane was added and heated at 65 °C for 2 days to prepare a silica fine particle dispersion D-1 modified with trimethylsilyl groups. In order to confirm the solid content concentration of the silica fine particle dispersion, 5 grams of the silica fine particle dispersion was weighed into an aluminum cup (1.3 grams), and ethanol and water as residual solvents were removed by heating in an oven at 150 °C for 24 hours or more. When the aluminum cup after the removal was weighed, it was 1.55 grams. Therefore, the solid content in 5 grams of the silica fine particle dispersion could be calculated as 0.25 grams, and the solid content concentration of the silica fine particle dispersion was confirmed to be 5% by mass. Then, when preparing the coating solution, ethanol in the silica fine particle dispersion was removed and the same amount of toluene as the removed ethanol was added, and it was carried out as a toluene dispersion. The result of the ESCA analysis of the silica fine particles surface-modified with trimethylsilyl groups was that C (carbon atom) was 8.5 at%.

[0048] <Synthesis method of fine particle dispersion D-2> 100 parts by mass of tetraethoxysilane and 49 parts by mass of ethanol were mixed in the reaction vessel 1. 60 parts by mass of ethanol, 13 parts by mass of aqueous ammonia (25%), and 536 parts by mass of deionized water were mixed in the reaction vessel 2, and then the content of the reaction vessel 2 was dropped into the reaction vessel 1 and transferred. At this time, in order to prevent a rapid reaction, the dropping was carried out over 30 minutes. After the dropping was completed, the reaction solution was left at 20 °C for 48 hours. Then, ammonia and water were distilled off to prepare a silica fine particle dispersion (average primary particle diameter: 800 nm). Then, 150 parts by mass of hexamethyldisilazane was added and heated at 65 °C for 2 days to prepare a silica fine particle dispersion D-2 modified with trimethylsilyl groups. In order to confirm the solid content concentration of the silica fine particle dispersion, 5 grams of the silica fine particle dispersion was weighed into an aluminum cup (1.3 grams), and ethanol and water of the residual solvent were removed by heating in an oven at 150 °C for 24 hours or more. When the aluminum cup after the removal was weighed, it was 1.55 grams. Therefore, the solid content in 5 grams of the silica fine particle dispersion could be calculated to be 0.25 grams, and the solid content concentration of the silica fine particle dispersion was confirmed to be 5% by mass. Then, when preparing the coating liquid, ethanol in the silica fine particle dispersion was removed, and toluene in the same amount as the removed ethanol was added, and it was carried out as a toluene dispersion. The result of the ESCA analysis of the silica fine particles surface-modified with trimethylsilyl groups was that C (carbon atom) was 9.0 at%.

[0049] <Production Example of Coating Liquid E-1> 40 parts by mass of an acid-modified polyolefin solution A-1 (solid content concentration: 10% by mass), 40 parts by mass of a silica fine particle dispersion D-1 (solid content concentration: 5% by mass), 44 parts by mass of toluene, 0.2 parts by mass of an epoxy curing agent YD128 (solid content concentration: 100% by mass), and 0.02 parts by mass of a catalyst TETRAD-X (solid content concentration: 100% by mass) were added to a sample bottle and mixed to prepare a coating liquid E-1 (solid content concentration: 5% by mass).

[0050] Hereinafter, coating liquids E-2 to E-12 for the second coating layer were mainly prepared in the same manner as the coating liquid E-1 except that each substance was blended as shown in Table 1. Table 1 shows the compositions of the coating liquids E-1 to E-12.

[0051]

Table 1

[0052] <Production of Coating Film> (Example 1) On the corona-treated surface of a film of polyethylene terephthalate (hereinafter sometimes referred to as PET film), Toyobo Estar (registered trademark) film (product number: E5100, thickness: 75 μm), polyester solution B-2 was applied using a bar coater #5, and then dried at 120 °C for 10 minutes to produce a first coating layer (the film thickness after drying of the first coating layer was 0.6 μm). Thereafter, coating solution E-1 prepared by the method described in the production example of the above coating solution was applied with a bar coater #5, and then dried at 110 °C for 60 minutes to produce a second coating layer, thereby obtaining a coating film (the film thickness after drying of the second coating layer was 0.6 μm).

[0053] (Examples 2 to 18) Hereinafter, by changing the coating solutions of the first coating layer and the second coating layer and the film thicknesses after drying of both coating layers as shown in Table 2, coating films of Examples 2 to 18 were obtained.

[0054] (Example 19) A coating film of Example 19 was obtained in exactly the same manner as in Example 1, except that the resin base film to be used was changed to Teonex (registered trademark) film (product number: Q51, thickness 38 μm) which is a film made of polyethylene naphthalate.

[0055] (Comparative Example 1) On the corona-treated surface of PET film E5100, acid-modified polyolefin solution A-2 was applied using a bar coater #5, and then dried at 120 °C for 1 minute to obtain a coating film.

[0056] (Comparative Example 2) After applying the coating liquid E-2 used in Example 2 onto the corona-treated surface of the PET film E5100 with a bar coater #5, the coated film was obtained by drying at 110°C for 60 minutes.

[0057] (Comparative Example 3) A coated film was obtained in the same manner as in Example 1 except that the film thicknesses of the first coating layer and the second coating layer after drying were changed as described in Table 2. The evaluation results of each example and comparative example are summarized in Table 2.

[0058]

Table 2

Industrial Applicability

[0059] According to the present invention, it is possible to provide a laminated film having excellent water and oil repellency and exhibiting antifouling properties. The laminated film according to the present invention can be applied to uses such as packaging, coating, and release materials, and is useful.

Claims

1. A laminated film having a coating layer containing a binder resin and silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups on a resin base film, wherein the total thickness of the coating layer is 3 μm or less, and the coating layer has a first coating layer having no silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups directly on the resin base film or via another layer, and a second coating layer having silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups on the first coating layer, and the silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups have a carbon atom ratio of 8 at% or more in a depth region of 10 nm by an X-ray photoelectron spectrometer (ESCA). When the thickness of the coating layer is divided into one hundred equal parts, with the interface between the resin base film and the coating layer being 0 and the outermost surface of the coating layer being 100, the laminated film in which the silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups are unevenly distributed only in the 30 - 100 part.

2. The laminated film according to claim 1, wherein the resin base film is a polyethylene terephthalate film or a polyethylene naphthalate film.

3. The laminated film according to claim 1 or 2, wherein the average primary particle diameter of the silica fine particles whose surface is hydrophobized by introducing trimethylsilyl groups is 30 nm to 1 μm.

4. The laminated film according to any one of claims 1 to 3, wherein the binder resin is an acid-modified polyolefin resin or a polyester resin.

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