Manufacturing method of laminated film

Abstract

[Problem] To provide a layered film which satisfactorily repels both water and oil and has excellent transparency and an efficient production method for the layered film. [Solution] A layered film which comprises a resinous substrate film and, formed thereon, a coating layer comprising a polyester resin A and fine particles C, the surfaces of which have been hydrophobized, and which has a haze of 10% or less and a water slippage angle of 10 degrees or larger but smaller than 70 degrees; and a method for producing the layered film, the method comprising superposing a coating layer using a coating fluid containing a specific solvent.

Description

[Technical Field]

[0001] The present invention relates to a laminated film and a method for producing the same, and more particularly to a laminated film that is water-repellent and oil-repellent and has excellent transparency, and an efficient method for producing the same. [Background technology]

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

[0003] Conventionally, methods for producing films with excellent water- and oil-repellency have been known, using silica fine particles with voids or fine particles that form aggregates to form voids (see, for example, Patent Documents 1 and 2).However, coating methods for imparting water- and oil-repellency to the film surface generally have the problem of low adhesion to the substrate, and the coating layer easily falling off, making it difficult to achieve both sufficient water- and oil-repellency and adhesion to the substrate.

[0004] In addition, conventional coating layers tend to become cloudy, making it difficult to maintain the transparency of the film itself. As such, it has been difficult to achieve both sufficient water and oil repellency and high transparency. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-106507 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-272198 Summary of the Invention

[0006] The present invention has been made in view of the problems of the conventional art, and an object of the present invention is to provide a laminated film that exhibits good liquid repellency to both water and oil and has excellent transparency, and an efficient method for producing the same. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have found that the above problems can be solved by the following means, and have arrived at the present invention. That is, the present invention has the following configuration. 1. A laminated film having a coating layer on a resin substrate film containing polyester resin A and fine particles C whose surface has been hydrophobized, and having a haze value of 10% or less and a water sliding angle of 10 degrees or more but less than 70 degrees. However, at least a part of the solvent B contained in the coating liquid for forming a coating layer, which contains the polyester resin A and the fine particles C whose surfaces have been hydrophobized, satisfies the following condition. The dispersion term, polarization term, and hydrogen bond term of the polyester resin A are δd1, δp1, and δh1, respectively, and the interaction radius is R0. The dispersion term, polarization term, and hydrogen bond term of the HSP value of the solvent B are δd2, δp2, and δh2, respectively. The dispersion term, polarization term, and hydrogen bond term of the HSP value of the hydrophobically treated microparticles C are δd3, δp3, and δh3, respectively, and the interaction radius is R1. The distance relationship between the substances is expressed by the following equations (1) and (2). Relationship between the distance between the HSP values ​​of the polyester resin A and the solvent B (R A-B ) 2 =4(δd2-δd1) 2 +(δp2-δp1) 2 +(δh2-δh1) 2 ···(1) Relationship between the distance between the HSP values ​​of the particles C whose surfaces have been hydrophobized and the solvent B (R C-B ) 2 =4(δd2-δd3) 2 +(δp2-δp3)2 +(δh2-δh3) 2 ···(2) In this case, the relative energy difference (RED), which is an index representing the affinity of the solvent B to the polyester resin A and the fine particles C whose surfaces have been hydrophobized, is expressed by the formulas (3) and (4), respectively. For example, the distance R between the HSP values ​​of the polyester resin A and the solvent B is A-B is equal to the radius of the Hansen melting sphere of the polyester resin A (RED) AB =1. Relative Energy Difference (RED) AB =(R A-B ) / R0···(3) Relative Energy Difference (RED) CB =(R C-B ) / R1···(4) Solvent B, whose HSP value is within the range satisfying formula (5), was used as the solvent for polyester resin A and for surface-hydrophobized fine particles C. The solvent may be a single solvent or a mixed solvent of multiple substances. (R A-B ) / R0≦1.5 and (R C-B ) / R1≦0.75 (5) 2. The laminated film according to claim 1, wherein the contact angle of the coating layer surface with decane is 40 degrees or more. 3. A laminate film according to claim 1 or 2, in which the atomic composition ratio is determined in a region 10 nm deep from the surface of the coating layer by measurement using an X-ray photoelectron spectroscopy (ESCA), and the ratio of fluorine atoms is 20 at% or more. 4. The laminated film according to any one of the above items 1 to 3, wherein the average primary particle diameter of the fine particles C whose surfaces have been hydrophobized is 30 nm to 500 nm. 5. The laminate film according to any one of items 1 to 4 above, wherein the resin substrate film is a polyethylene terephthalate film or a polyethylene naphthalate film. 6. A method for producing a laminated film having a coating layer on a resin substrate film containing polyester resin A and fine particles C whose surfaces have been hydrophobized, wherein the haze value of the laminated film is 10% or less, the water sliding angle is 10 degrees or more and less than 70 degrees, and in preparing a coating liquid for forming the coating layer, solvent B used at least when mixing polyester resin A and fine particles C whose surfaces have been hydrophobized satisfies the following conditions: The dispersion term, polarization term, and hydrogen bond term of the polyester resin A are δd1, δp1, and δh1, respectively, and the interaction radius is R0. The dispersion term, polarization term, and hydrogen bond term of the HSP value of the solvent B are δd2, δp2, and δh2, respectively. The dispersion term, polarization term, and hydrogen bond term of the HSP value of the hydrophobically treated microparticles C are δd3, δp3, and δh3, respectively, and the interaction radius is R1. The distance relationship between the substances is expressed by the following equations (1) and (2). Relationship between the distance between the HSP values ​​of the polyester resin A and the solvent B (R A-B ) 2 =4(δd2-δd1) 2 +(δp2-δp1) 2 +(δh2-δh1) 2 ···(1) Relationship between the distance between the HSP values ​​of the particles C whose surfaces have been hydrophobized and the solvent B (R C-B ) 2 =4(δd2-δd3) 2 +(δp2-δp3) 2 +(δh2-δh3) 2 ···(2) In this case, the relative energy difference (RED), which is an index representing the affinity of the solvent B to the polyester resin A and the fine particles C whose surfaces have been hydrophobized, is expressed by the formulas (3) and (4), respectively. For example, the distance R between the HSP values ​​of the polyester resin A and the solvent B is A-B is equal to the radius of the Hansen melting sphere of the polyester resin A (RED) AB =1. Relative Energy Difference (RED) AB =(R A-B ) / R0···(3) Relative Energy Difference (RED) CB =(R C-B ) / R1···(4) Solvent B, whose HSP value falls within the range satisfying formula (5), is used as the solvent for polyester resin A and surface-hydrophobized fine particles C. The solvent may be a single solvent or a mixed solvent of multiple substances. (R A-B ) / R0≦1.5 and (R C-B ) / R1≦0.75 (5) [Effects of the Invention]

[0008] The laminate film of the present invention exhibits high droplet removal properties by using a polyester resin as the binder resin forming the coating layer and incorporating surface-hydrophobized microparticles into the coating layer. Furthermore, by using a solvent with good affinity for the polyester resin when mixing the surface-hydrophobized microparticles, the transparency of the substrate film is maintained, making it possible to provide a laminate film with excellent transparency. Furthermore, the present invention also makes it possible to provide an efficient method for producing the laminate film. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention provides a laminated film having excellent liquid repellency on the surface of a coating layer and excellent transparency.

[0010] (Resin substrate film) The laminated film of the present invention has a resin substrate film. The material of this resin substrate film is not particularly limited, but a resin film is preferred from the viewpoint of handling properties such as flexibility. Examples of resins 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; and polyurethane resins. Examples of suitable resins include cellulose-based resins such as cellulose acetate and ethyl cellulose, aromatic hydrocarbon polymers such as polyarylates, aramids, polycarbonates, polyphenylene sulfides, polyphenylene oxides, polysulfones, polyethersulfones, polyetheretherketones, polyetherimides, polyimides, polyamideimides, polybenzimidazoles, polybenzoxazoles, and polybenzothiazoles, fluorine-based resins such as polytetrafluoroethylene and polyvinylidene fluoride, epoxy resins, phenolic resins, novolac resins, and benzoxazine resins. Among these, films made of polyester resins or acrylate resins are preferred from the viewpoints of transparency and dimensional stability. Specific examples of polyester resins include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred from the viewpoint of physical properties, and polyethylene terephthalate is particularly preferred from the viewpoint of balancing physical properties and cost.

[0011] The resin substrate film may be a single layer, or may have two or more layers laminated thereto. When two or more layers are laminated, films of the same or different types may be laminated. A resin composition may also be laminated on the resin substrate film. Furthermore, various additives may be contained in the resin substrate film as needed, as long as the effects of the present invention are achieved. Examples of additives include antioxidants, light stabilizers, antigelling agents, organic wetting agents, antistatic agents, UV absorbers, surfactants, etc. When the resin substrate film is composed of two or more layers, additives may also be contained in each layer depending on its function. In order to improve the handling properties, such as slipperiness and windability, of the resin substrate film, inactive particles may be contained in the resin substrate film.

[0012] In the present invention, the thickness of the resin substrate film is not particularly limited, but is preferably 5 μm or more and 300 μm or less, more preferably 10 μm or more and 280 μm or less, and even more preferably 12 μm or more and 260 μm or less. A thickness of 5 μm or more makes it easy to apply the coating layer when laminating it, and a thickness of 300 μm or less is advantageous in terms of cost.

[0013] The surface of the resin substrate film may be untreated, or may be subjected to a surface treatment such as plasma treatment, corona treatment or flame treatment, or may be coated with a primer layer.

[0014] (Fine particles C with hydrophobic surface treatment) The laminated film of the present invention has a coating layer on a resin substrate film directly or via another layer, and the coating layer contains fine particles C whose surfaces have been hydrophobized. Hereinafter, fine particles whose surfaces have been hydrophobized may be referred to as surface-modified fine particles, but there is no significant difference between the two terms. The type of fine particles is not particularly limited. For example, at least one type of fine particle, such as silica (silicon dioxide), alumina, titania, or zirconia, can be used. These fine particles may be synthesized via any compound, or known or commercially available fine particles may be used. Silica (silicon dioxide) fine particles are particularly preferred because they are easily surface-treated as described below.

[0015] The fine particles C have a hydrophobic surface, but the method of treatment is not particularly limited, and may be, for example, hydrophilic oxide fine particles whose surfaces have been modified. That is, hydrophilic oxide fine particles may be surface-modified with any reagent such as a silane coupling agent, and the surface may be treated.

[0016] For the hydrophobic treatment of fine particles, such as silica fine particles, surface treatment with various known reagents, such as silicone oil, silane coupling agents, and silazanes, is preferred. From the viewpoint of achieving excellent water and oil repellency, it is particularly preferred to introduce fluorine-based functional groups, such as 1H,1H,2H,2H-perfluorooctyl, 1H,1H,2H,2H-perfluorodecyl, 1H,1H,2H,2H-perfluorohexyl, and 3,3,3-trifluoropropyl, alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and octyl, alkenyl, alkynyl, vinyl, cyclohexyl, styryl, phenyl, and trimethylsilyl groups, onto the surface. Among these, oxide fine particles having 1H,1H,2H,2H-perfluoroalkyl groups introduced therein are preferred, as they exhibit superior water and oil repellency, and silica fine particles having 1H,1H,2H,2H-perfluorooctyl groups introduced therein are particularly preferred.

[0017] In the present invention, when the atomic composition ratio is determined in a region 10 nm deep from the surface of the coating layer by measurement using an X-ray photoelectron spectroscopy (ESCA), the ratio of fluorine atoms is preferably 20 at% or more from the viewpoint of water and oil repellency. More preferably, it is 25 at% or more, and particularly preferably, it is 30 at% or more. The ratio of fluorine atoms is preferably high, but may be 50 at% or less.

[0018] The primary particle diameter of the fine particles C in the present invention is preferably 5 nm to 2 μm, more preferably 20 nm to 1.5 μm, even more preferably 30 nm to 1 μm, and most preferably 30 nm to 500 nm. A diameter of 5 nm or more is preferred because it facilitates the formation of irregularities on the surface of the coating layer and makes it easier to increase the contact angle (described below). On the other hand, a diameter of 2 μm or less is preferred because it reduces the likelihood of fine particles falling off the coating layer and also facilitates maintaining the transparency of the resin substrate film. In the present invention, the average primary particle diameter can be determined based on the results of morphological observation using a microscope such as a scanning electron microscope or a transmission electron microscope. Specifically, the average diameter of 20 fine particles randomly selected in these microscope observations is taken as the average diameter of the primary particles. The average primary particle diameter of irregularly shaped fine particles can be calculated as the circle-equivalent diameter. The circle-equivalent diameter is calculated by dividing the area of ​​the observed fine particles by π, calculating the square root, and then multiplying it by two.

[0019] In the present invention, the coating layer of the laminate film preferably includes a coating layer containing polyester resin A and fine particles C whose surface has been hydrophobized. The coating layer may be the only coating layer containing polyester resin A and fine particles C whose surface has been hydrophobized, or may include other coating layers, resulting in two or more coating layers being laminated. When two or more coating layers are laminated, it is preferable that the coating layer containing polyester resin A and fine particles C whose surface has been hydrophobized be the outermost coating layer from the viewpoints of water and oil repellency and stain resistance. The composition of the coating layer (sometimes referred to as the first coating layer) located between the resin substrate film and the coating layer containing polyester resin A and fine particles C whose surface has been hydrophobized can be selected taking into consideration the adhesion between the resin substrate film and the coating layer containing polyester resin A and fine particles C whose surface has been hydrophobized. The first coating layer preferably does not impair the transparency of the laminate film.

[0020] (binder resin) The binder resin used to form the coating layer in the present invention is not particularly limited as long as it is a component that can adhere well to the resin substrate film. For example, polyester resin, acid-modified polyolefin resin, polyurethane resin, epoxy resin, acrylic resin, etc. are preferably used. Furthermore, from the viewpoint of adhesion to the resin substrate film, it is preferable to use a polyester resin or acid-modified polyolefin resin for the first coating layer, and from the viewpoint of improving liquid repellency and maintaining film transparency, it is preferable to use a polyester resin for the second coating layer. In the present invention, such polyester resins may be referred to as polyester resin A.

[0021] There are no particular limitations on the polyester resin A that is preferably used as the binder resin for the coating layer, but polyester resins such as those in the Vylon (registered trademark) series manufactured by Toyobo Co., Ltd. are preferably used.

[0022] The binder resin may be used after being mixed with a curing agent to crosslink it, and the curing agent used is preferably isocyanate, epoxy, melamine, or carboxylic acid, more preferably epoxy or melamine, which allows the formation of a coating layer containing fine particles C whose surface has been hydrophobized while maintaining the transparency of the resin substrate film.

[0023] (Other components in the coating layer) The coating layer of the present invention may contain components other than the above-mentioned fine particles C whose surfaces have been hydrophobized. Specific examples include 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.

[0024] (Coating layer structure) The total thickness of the coating layer is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 30 nm or more, and particularly preferably 50 nm or more, from the viewpoint of satisfactory adhesion between the coating layer and the resin substrate film. Also, taking into consideration the transparency and economic efficiency of the coating layer, the total thickness of the coating layer is preferably 3 μm or less, more preferably 2 μm or less, even more preferably 1.5 μm or less, and particularly preferably 1.2 μm or less.

[0025] The solid content of the coating liquid is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and even more preferably 1.5% by mass to 10% by mass. This range is preferred because the irregularities of the fine particles are easily exposed on the coating surface and the coating properties are also good.

[0026] The mixing ratio of the fine particles to the binder resin (binder resin:fine particles) is preferably in the range of 90:10 to 5:95, more preferably 70:30 to 5:95, and even more preferably 50:50 to 5:95. Within the above range, the fine particles are preferable because they have irregularities on the surface but are unlikely to fall off the binder.

[0027] (Hansen Solubility Parameter: HSP) The Hansen solubility parameter (HSP) is a vector parameter obtained by dividing the Hildebrand solubility parameter into three cohesive energy components: London dispersion force, dipole-dipole force, and hydrogen bonding force. In this specification, the component of the HSP corresponding to the London dispersion force is referred to as the dispersion term (hereinafter also referred to as "δd"), the component corresponding to the dipole-dipole force is referred to as the polar term (hereinafter also referred to as "δp"), and the component corresponding to the hydrogen bonding force is referred to as the hydrogen bonding term (hereinafter also referred to as "δh"). Because the HSP is a vector quantity, it is known that there are very few pure substances with exactly the same value. Furthermore, databases have been established for the HSPs of commonly used substances. Therefore, those skilled in the art can obtain the HSP value of a desired substance by referring to these databases. Even for substances whose HSP values ​​are not registered in databases, those skilled in the art can calculate the HSP value from their chemical structure using computer software such as Hansen Solubility Parameters in Practice (HSPiP). Alternatively, for a substance for which HSP values ​​are not registered, dissolution tests can be performed using multiple solvents with known HSP values, and the resulting solubilities can be entered into HSPiP to determine the HSP value. In the case of a mixture of multiple substances, the HSP value of the mixture is calculated as the sum of the values ​​obtained by multiplying the HSP values ​​of each component substance by the volume ratio of that substance to the entire mixture. For details on HSP values, see, for example, Hiroshi Yamamoto, S. Abbott, C.M. Hansen, Chemical Industry, March 2010 issue. For details on HSP, see, for example, Hiroshi Yamamoto, S. Abbott, C.M. Hansen, Chemical Industry, April 2010 issue. The HSP value of polyester resin A, which is the binder resin in this specification, and its interaction radius R0 with solvent B were determined using the dissolution test method described in S. Abbott, C.M. Hansen, Chemical Industry, March 2010 issue and Hiroshi Yamamoto, S. Abbott, C.M. Hansen, Chemical Industry, April 2010 issue. Since the dissolution test method cannot be applied to fine particles C whose surfaces have been hydrophobically treated, the HSP value of fine particles C whose surfaces have been hydrophobically treated and its interaction radius R1 with solvent B were determined using the sedimentation test method described below. The Hansen solubility parameters of various resins and fine particles vary depending on the monomer structure, molecular weight, molecular weight distribution, crystallinity, surface modification rate, etc. The interaction radius R0 indicates the distance from the center coordinate where the target substance is soluble when the coordinate of the solubility parameter (HSP) of the target substance in Hansen space is taken as the center coordinate. The interaction radius R0 is usually determined by conducting a solubility test in which the target substance is dissolved in various solvents with determined HSP. Specifically, when the coordinates of the Hansen solubility parameters of all solvents used in the solubility test are plotted in Hansen space, a sphere (dissolution sphere) is found where the coordinates of the solvent that dissolved the target substance are inside the sphere and the coordinates of the solvent that did not dissolve the target substance are outside the sphere, and the radius of this dissolution sphere is taken as the interaction radius R0 of the target substance.

[0028] Generally, the distance R between the Hansen solubility parameter of substance X and the Hansen solubility parameter of substance Y is X - Y satisfies the following relation (6): X , δp X and δh X are the dispersion term, the polarization term, and the hydrogen bond term of the Hansen solubility parameter of substance X, respectively. Y , δp Y and δh Y denote the dispersion term, polarization term, and hydrogen bonding term of the Hansen solubility parameter of substance Y, respectively. (R X-Y ) 2 =4(δd Y -δd X ) 2+(δp Y -δp X ) 2 +(δh Y -δh X ) 2 ···(6)

[0029] Generally, the relative energy difference (RED), which is an index showing the affinity between substances X and Y, is expressed by the following general formula (7) when both substances are dissolved in a solvent. Relative Energy Difference (RED) XY =(R X-Y ) / R0···(7) In the present invention, the distance Ra-b between the Hansen solubility parameter of polyester resin A and the Hansen solubility parameter of solvent B has the relationship of the following formula (1): where δd1, δp1, and δh1 represent the dispersion term, polarization term, and hydrogen bond term of the Hansen solubility parameter of polyester resin A, respectively. Also, δd2, δp2, and δh2 represent the dispersion term, polarization term, and hydrogen bond term of the Hansen solubility parameter of solvent B, respectively. (R A-B ) 2 =4(δd2-δd1) 2 +(δp2-δp1) 2 +(δh2-δh1) 2 ···(1)

[0030] In addition, the relative energy difference (RED) is an index showing the affinity between the polyester resin A and the solvent B in the present invention. AB is expressed by the following general formula (3): In this case, for example, the distance R between the HSP values ​​of polyester resin A and solvent B is A-B When is equal to the radius of the Hansen melting sphere of polyester resin A (RED) AB =1. Relative Energy Difference (RED) AB =(R A-B ) / R0···(3)

[0031] (Sedimentation test method) The dissolution test method is a suitable method for determining the HSP value of resins and solvents, but since microparticles do not dissolve in solvents, a different method is required to determine their HSP value. In this invention, the sedimentation test method was used to determine the HSP value of microparticles C whose surfaces have been hydrophobized. The specific examination procedure is as follows.

[0032] First, the computer software HSPiP is used to confirm the HSP value of the compound used to modify the surface of hydrophobized microparticle C. At this time, if the site that bonds with the silica particle is a polar functional group, confirming the HSP value with a structure converted to a non-polar functional group will make it easier to appropriately select the test solvent later. Next, using the HSP values ​​of the confirmed modified compounds as a reference, select 10 or more solvents to be used in the sedimentation test. At this time, selecting solvents with different HSP values ​​so that there is as little bias as possible in the Hansen space will allow for more accurate estimation of the HSP value. Also, by obtaining a fairly appropriate estimate of the HSP value in the previous step, it will be possible to select test solvents based on the estimated HSP value. 0.1 g of hydrophobically treated microparticles C was weighed out and placed in a sample bottle, and 10 ml of the test solvent selected using the method described above was added. Then, ultrasonic waves were applied for 5 minutes in an ultrasonic cleaner, and the same treatment was carried out for each sample bottle using any dispersion solvent. After ultrasonic irradiation, the sample was left to stand at room temperature for 1 hour, and then the dispersion state was visually judged and scored. The criteria for scoring are as follows: 1. Particles are uniformly dispersed 2. Particles are dispersed uniformly, but there is very little settling. 3. Most of the particles are uniformly dispersed, but 20-50% settle. 4. Some particles are dispersed, but 50-80% settle. 5. Some particles are dispersed, but more than 80% have settled. 6. Particles have completely settled These results are input into the computer software HSPiP, and only score 1 is defined as being inside the Hansen sphere, thereby determining the HSP value of the microparticle and the Hansen sphere.

[0033] (Solvent B) The solvent used when mixing polyester resin A and hydrophobically treated microparticles C can be a single solvent or a mixture of multiple solvents. However, using a solvent with a high affinity for polyester resin A and hydrophobically treated microparticles C results in a more transparent film. The HSP value can be used as a reference for determining the affinity between polyester resin A and hydrophobically treated microparticles C and solvent B. The distance between the HSP values ​​of hydrophobically treated microparticles C and solvent B is expressed by the following equation (2), where the dispersion term, polarization term, and hydrogen bond term of the Hansen solubility parameters for the HSP value of hydrophobically treated microparticles C are δd3, δp3, and δh3, respectively, and the interaction radius is R1. The interaction radius R1 of the hydrophobically treated microparticles is calculated by inputting the results of a sedimentation test into HSPiP. (R C-B ) 2 =4(δd2-δd3) 2 +(δp2-δp3) 2 +(δh2-δh3) 2 ···(2) At this time, the relative energy difference (RED) is an index that indicates the affinity of solvent B to particle C whose surface has been hydrophobized. CB is expressed by equation (4). Relative Energy Difference (RED) CB =(R C-B ) / R1···(4)

[0034] In the present invention, solvent B, whose HSP value is within the range satisfying relational expression (5), was used as the solvent for polyester resin A and for fine particles C, the surfaces of which were hydrophobically treated. Solvent B may be a single solvent or a mixed solvent of multiple substances. (R A-B ) / R0≦1.5 and (R C-B ) / R1≦0.75 (5)

[0035] For example, (R A-B Examples of solvents that satisfy the condition (R ) / R ≦ 1.5 include 2-cyclopentyl alcohol, ethylene dibromide, 1,4-dioxane, 1,2-ethanedithiol, and 2-methyl-1-butanol. C-B Examples of solvents that satisfy the relationship (R ) / R1≦0.75 include 1-chloro-2-butene, ethyl bromide, 1-chlorohexane, methyl ethyl ketone, and methyl isobutyl ketone. In addition, a mixed solvent may be used, and (R A-B When the mixed solvents satisfying (R ) / R0≦1.5 are expressed as a mass blending ratio, examples include methyl ethyl ketone:1,4-dioxane=1:9 to 9:1, 1,4-dioxane:acetone=1:9 to 9:1, toluene:methyl ethyl ketone=0:10 to 9:1, dimethyl cellosolve:n-butyl acetate=1:9 to 9:1, and acetone:methyl isobutyl ketone=1:9 to 9:1. C-B When mixed solvents that satisfy the relationship ) / R1≦0.75 are expressed as a mass blending ratio, examples include 1-chloro-2-butene:bromotrichloromethane=5:5 to 10:0, 2-chlorobutane:o-difluorobenzene=1:9 to 9:1, 1-chlorohexane:3-ethoxypropionaldehyde=3:7 to 10:0, toluene:methyl ethyl ketone=0:10 to 5:5, and methyl ethyl ketone:cyclohexane=4:6 to 10:0. (R A-B ) / R0≦1.5 and (R C-B Solvents that satisfy the formula (1) / R1≦0.75, expressed as mass ratios, include xylene:methyl ethyl ketone = 1:9 to 5:5, toluene:methyl ethyl ketone = 0:10 to 5:5, acetonitrile:cyclohexane = 2:8 to 6:4, and methyl ethyl ketone:cyclohexane = 4:6 to 10:0. Relative Energy Difference (RED) AB The value of is preferably 1.5 or less, more preferably 1.0 or less, and most preferably 0.5 or less. (RED) AB The value of is preferably small, but may be 0.1 or more. (RED) CBThe value is preferably 0.75 or less, more preferably 0.5 or less, and most preferably 0.4 or less. (RED) CB The value of is preferably small, but may be 0.1 or more.

[0036] In the present invention, in preparing a coating liquid for forming a coating layer containing polyester resin A and surface-hydrophobized fine particles C, it is preferable from the viewpoint of the transparency of the laminate film that solvent B used at least during mixing of polyester resin A and surface-hydrophobized fine particles C satisfies the above-mentioned conditions. Therefore, while it is not necessary for all of the solvents contained in the intermediate solutions and suspensions prepared in the process up to the preparation of the coating liquid for the coating layer of the laminate film to satisfy the above-mentioned conditions, it is more preferable from the viewpoint of the transparency of the laminate film that all of the solvents contained in the intermediate solutions and suspensions prepared in the process up to the preparation of the coating liquid for the coating layer of the laminate film satisfy the above-mentioned conditions. Furthermore, it is particularly preferable from the viewpoint of the transparency of the laminate film that all of the solvents contained in the intermediate solutions and suspensions prepared in the process up to the preparation of the coating liquid for the coating layer of the laminate film satisfy the above-mentioned conditions and are solvents of the same composition.

[0037] Furthermore, in the drying step after coating, it is preferable to completely remove the solvent, and in consideration of the heat resistance of the substrate film, it is preferable to use a solvent with a boiling point of 150° C. or less.

[0038] (Primary particle diameter of fine particles C with hydrophobic surface treatment) It can be determined by observing the morphology using a microscope such as a scanning electron microscope or a transmission electron microscope. Specifically, the average diameter of 20 particles randomly selected during the microscope observation is taken as the average primary particle diameter.

[0039] (transparency) In the present invention, it is preferable that the transparency of the resin substrate film is maintained even after a coating layer is provided to form a laminate film, and the haze value is preferably 10% or less, more preferably 9% or less. A small haze value is preferable, but the haze value is usually 0.1% or more.

[0040] (liquid repellency) The water / oil repellency and liquid repellency of the laminated film according to the present invention can be evaluated by known methods. Specifically, oil repellency can be evaluated primarily by measuring the contact angle using decane, specifically n-decane. In the present invention, the contact angle with decane is preferably 40 degrees or more, more preferably 50 degrees or more. The larger the contact angle with decane, the better, and there is no particular upper limit, but in reality, the upper limit is about 150 degrees. A contact angle with decane of 40 degrees or more is preferred from the viewpoint of imparting oil repellency capable of suppressing oil stains, etc., and a contact angle of 50 degrees or more is more preferred from the viewpoint of exhibiting oil repellency equivalent to or better than that of conventional fluororesin sheets.

[0041] (Dynamic liquid repellency) The dynamic liquid repellency of the laminated film of the present invention can be evaluated by the following two methods: measuring the sliding angle of the laminated film and evaluating the mass change rate after immersion in oil. In the present invention, the sliding angle measurement is mainly used.

[0042] (Sliding angle measurement) The sliding angle can be measured by a known method. In the present invention, the preferred range of the sliding angle of water is preferably 10 degrees or more and less than 70 degrees. A sliding angle of 10 degrees or more and less than 70 degrees is preferred because the droplets slide down without being pinned on the substrate. Furthermore, a state in which no trace of the droplet remains after sliding down is preferred because this can be said to be a state in which the droplets have been completely removed. A more preferred angle is 10 degrees or more and 50 degrees or less.

[0043] (1) Hansen Solubility Parameter (HSP) and Interaction Radius The dispersion term (δd2), polarization term (δp2), and hydrogen bond term (δh2) of the HSP value of solvent B used in the examples and comparative examples described below were determined by referring to constants registered in publicly known databases.

[0044] The dispersion term (δd1), polarization term (δp1), and hydrogen bond term (δh1) of the HSP value of polyester resin A used as a binder were calculated by conducting a dissolution test using a solvent with known HSP.

[0045] The dispersion term (δd3), polarization term (δp3), and hydrogen bond term (δh3) of the HSP values ​​of fluorine-modified silica particles, which are fine particles C with hydrophobic surfaces, were calculated by conducting a sedimentation test using a solvent with known HSP properties.

[0046] (Laminated film manufacturing process) The coating method for producing the laminate film of the present invention is not particularly limited. For example, the film 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 in these coating methods is not particularly limited, but an organic solvent with good affinity with the binder resin must be appropriately selected. These solvents may be used alone or in combination. The content of the hydrophobic surface-treated microparticles relative to the solvent can be selected at any ratio that results in a uniform dispersion. The drying method after coating can be either natural drying or heat drying, but heat drying is preferred from the perspective of industrial production. The drying temperature is not particularly limited as long as it does not affect the components contained in the resin substrate film or coating layer. However, a temperature of 150°C or less is generally preferred, and a temperature between 50°C and 140°C is more preferred. The drying method is not particularly limited, and known methods for drying films, such as a hot plate or hot air oven, can be used. The drying time can be appropriately selected depending on other conditions such as the drying temperature, as long as it does not affect the components contained in the resin substrate film or coating layer. The coating process may be a so-called offline coating method, which is carried out in a separate process after the production of the resin substrate film, or a so-called in-line coating method, in which a coating liquid is applied to an unstretched sheet or a uniaxially stretched film during the production process of the resin substrate film, and the film is stretched in at least one direction. [Example]

[0047] The present invention will be further explained below with reference to specific examples, but the present invention is not limited to these examples. First, the evaluation methods employed in the present invention will be explained.

[0048] <Evaluation method> The evaluations in the examples and comparative examples were carried out by the following measurement methods.

[0049] (Hansen Solubility Parameter (HSP) value and interaction radius) The dispersion term (δd2), polarization term (δp2), and hydrogen bond term (δh2) of the HSP values ​​of the solvents used in the examples and comparative examples were determined by referring to constants registered in publicly known databases.

[0050] The dispersion term (δd1), polarization term (δp1), and hydrogen bond term (δh1) of the HSP value of RV280, a binder resin corresponding to polyester resin A in the present invention, were calculated by conducting a dissolution test using a solvent with known HSP properties.

[0051] The dispersion term (δd3), polarization term (δp3), and hydrogen bond term (δh3) of the HSP values ​​of silica microparticles corresponding to the microparticles C whose surfaces have been hydrophobized in the present invention were calculated by conducting a sedimentation test using a solvent with known HSP properties.

[0052] Then, the following formula: (Ra-b) 2 =4(δd2-δd1) 2 +(δp2-δp1) 2 +(δh2-δh1) 2 (Rc-b) 2 =4(δd3-δd1) 2 +(δp3-δp1) 2 +(δh3-δh1) 2 [In the above formula, δd1 is the dispersion term of the HSP of the binder resin, δp1 is the polarization term of the HSP of the binder resin, δh1 is the hydrogen bond term of the HSP of the binder resin, δd2 is the dispersion term of the HSP of the solvent, δp2 is the polarization term of the solvent HSP, δh2 is the hydrogen bond term of the solvent HSP, δd3 is the dispersion term of the HSP of silica particles, δp3 is the polarization term of the HSP of silica particles, δh3 is the hydrogen bond term of the HSP of silica particles, Ra-b is the distance between the HSP values ​​of the binder resin and the solvent in the HSP space, and Rc-b is the distance between the HSP values ​​of the silica fine particles and the solvent in the HSP space. The distance "Ra-b" between the HSP values ​​of the binder resin and the solvent, and the distance "Rc-b" between the HSP values ​​of the silica fine particles and the solvent were calculated.

[0053] The interaction radius (R0) of the binder resin was calculated by inputting the results of the dissolution test into HSPiP. The interaction radius (R1) of the silica microparticles was calculated by inputting the results of the sedimentation test into HSPiP.

[0054] (Contact angle measurement) The contact angle of the coating layer surface of the prepared laminated film with respect to the solvent was measured. A contact angle meter DM-501 manufactured by Kyowa Interface Science Co., Ltd. was used for the contact angle measurement. n-Decane was used as the measurement solvent. The contact angle of n-Decane (hereinafter sometimes abbreviated as DCA) was measured after 10 seconds from the application of a 1.8 μL droplet of n-Decane.

[0055] (Sliding angle measurement) For the sliding angle measurement, a laminated film cut into a strip of approximately 2 cm x 5 cm was used. Measurements were performed using a fully automatic contact angle meter DMo-701 from Kyowa Interface Science Co., Ltd., using a water volume of 30 μL. The sliding angle was determined as the stage tilt angle at the point where the droplet had moved 30 dots.

[0056] (Measurement of the mean diameter of primary particles) The average primary particle diameter of the hydrophobized surface microparticles was determined by observation using a scanning electron microscope or a transmission electron microscope. Specifically, the average diameter of 20 microparticles randomly selected during these microscopic observations was taken as the average primary particle diameter. The average primary particle diameter of irregularly shaped microparticles can be calculated as the equivalent circle diameter. The equivalent circle diameter is calculated by dividing the area of ​​the observed microparticles by π, calculating the square root, and then multiplying it by two.

[0057] (Fluorine atom ratio at a depth of 10 nm from the coating layer surface) The fluorine atom ratio on the surface of the coating layer can be calculated from the results of measurements using an X-ray photoelectron spectroscopy (ESCA). The composition was analyzed in a region 10 nm deep from the surface of the coating layer of the laminated film. The apparatus used was K-Alpha+ (manufactured by Thermo Fisher Scientific). Details of the measurement conditions are shown below. During analysis, background was removed by the Shirley method. The surface composition ratio was calculated as the average value of the measurement results at three or more locations. Measurement conditions Excitation X-ray: Monochromated AlKα line X-ray output: 12kV, 6mA Photoelectron escape angle: 90 degrees Spot size: 400μmΦ Pass energy: 50eV Step: 0.1eV

[0058] (HAZE value) The haze value was measured using a haze meter NDH 5000 manufactured by Nippon Denshoku Industries Co., Ltd. Measurements were taken at three points on a 50 mm x 80 mm coating film, and the average value was calculated.

[0059] The reagents used in the examples and comparative examples are listed below. Vylon (registered trademark) RV280 (polyester resin manufactured by Toyobo) MS-001 (Methylated melamine resin manufactured by Sanwa Chemical) p-Toluenesulfonic acid monohydrate (Nacalai Tesque, crosslinking catalyst)

[0060] <Production Example of Polyester Resin Solution A-1> 10 parts by mass of Vylon (registered trademark) RV280 (polyester resin manufactured by Toyobo), 57 parts by mass of toluene, and 133 parts by mass of methyl ethyl ketone were added to a sample bottle and stirred at room temperature for 1 hour to prepare polyester resin solution A-1 (solid content concentration 5% by mass).

[0061] Thereafter, polyester solutions A-2 to A-6 were prepared in the same manner as polyester resin solution A-1, except that the solvent was changed as shown in Table 1.

[0062] [Table 1]

[0063] <Production Example of Polyester Resin Solution B-1> 100 parts by mass of polyester solution A-1, 1.5 parts by mass of toluene, 3.5 parts by mass of methyl ethyl ketone, 0.5 parts by mass of melamine resin MS-001 as a crosslinking agent, and 0.01 parts by mass of paratoluenesulfonic acid (PTS) as a crosslinking catalyst were added to a sample bottle and stirred at room temperature for 5 minutes to prepare polyester resin solution B-1 (solids concentration 5% by mass).

[0064] Thereafter, polyester resin solutions B-2 to B-6 were prepared in the same manner as polyester resin solution B-1, except that the solvent was changed as shown in Table 1.

[0065] [Table 2]

[0066] <Method for synthesizing silica particle dispersion C-1> 100 parts by weight of tetraethoxysilane and 429 parts by weight of ethanol were mixed in reaction vessel 1. 179 parts by weight of ethanol, 13 parts by weight of aqueous ammonia (25%), and 37 parts by weight of deionized water were mixed in reaction vessel 2, and the contents of reaction vessel 2 were then transferred dropwise to reaction vessel 1. The mixture was added dropwise over 10 minutes to prevent a rapid reaction. After the addition was completed, the reaction solution was left at 20°C for 48 hours. The ammonia and water were then distilled off to produce a silica microparticle dispersion (average primary particle diameter 70 nm). Next, 1136 parts by weight of ethanol, 11.4 parts by weight of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, and 3.8 parts by weight of aqueous ammonia (25%) were added to the silica microparticle dispersion and heated at 65°C for 2 days to produce silica microparticle dispersion D-1 modified with 1H,1H,2H,2H-perfluorooctyl groups. To confirm the solids concentration of the silica microparticle dispersion, 5 grams of the silica microparticle dispersion was weighed into an aluminum cup (1.3 grams) and heated in an oven at 150°C for more than 24 hours to remove the residual solvents, ethanol and water. The aluminum cup weighed 1.4 grams after removal, so the solids content in 5 grams of silica microparticle dispersion was calculated to be 0.1 grams, and the solids concentration of the silica microparticle dispersion was confirmed to be 2% by mass. When preparing the coating solution, the ethanol was removed from the silica microparticle dispersion and an equal amount of a mixed solvent of toluene:methyl ethyl ketone = 3:7 (mass ratio) was added to prepare a toluene / methyl ethyl ketone dispersion.

[0067] Thereafter, silica fine particle dispersions C-2 to C-6 were prepared in the same manner as silica fine particle dispersion C-1, except that the solvent was changed as shown in Table 3.

[0068] [Table 3]

[0069] <Production example of coating liquid D-1> Coating liquid D-1 (solid content concentration 2% by mass) was prepared by adding 40 parts by mass of polyester resin solution A-1 (solid content concentration 5% by mass), 100 parts by mass of silica microparticle dispersion C-1 (solid content concentration 2% by mass), 74 parts by mass of a mixed solvent of toluene:methyl ethyl ketone = 3:7 (mass ratio), 0.2 parts by mass of crosslinker MS-001 (solid content concentration 10% by mass), and 0.004 parts by mass of catalyst p-toluenesulfonic acid (solid content concentration 100% by mass) to a sample bottle and mixing them.

[0070] Hereinafter, coating solutions D-2 to D-6, mainly for the second coating layer, were prepared in the same manner as coating solution D-1, except that the respective substances were blended as shown in Table 4.

[0071] [Table 4]

[0072] <Preparation of laminated film> Example 1 Polyester resin solution B-2 was applied to the corona-treated surface of Toyobo Ester (registered trademark) film (product number: E5100, thickness: 75 μm), which is a polyethylene terephthalate (hereinafter sometimes referred to as PET film), using bar coater #5, and then dried at 110°C for 1 minute to produce a first coating layer (the first coating layer had a thickness of 0.6 μm after drying). Subsequently, coating liquid D-1, prepared by the method described in the coating liquid production example above, was applied using bar coater #3, and then dried at 130°C for 1 minute to produce a second coating layer, thereby obtaining a laminated film (the second coating layer had a thickness of 0.14 μm after drying).

[0073] Thereafter, laminated films of Examples 2 to 5 were obtained in the same manner as in Example 1, except that the coating liquid to be applied was changed as shown in Table 5.

[0074] (Comparative Example 1) Polyester solution B-1 (solid content 5% by mass) was applied to the corona-treated surface of PET film E5100 using bar coater #5, and then dried at 110° C. for 1 minute to obtain a laminated film.

[0075] (Comparative Example 2) A laminated film of Comparative Example 2 was obtained in the same manner as in Example 1, except that the coating liquid for the first coating layer was changed to B-5 and the coating liquid for the second coating layer was changed to D-5.

[0076] (Comparative Example 3) A laminated film of Comparative Example 3 was obtained in the same manner as in Example 1, except that the coating liquid for the first coating layer was changed to B-6 and the coating liquid for the second coating layer was changed to D-6.

[0077] [Table 5] [Industrial Applicability]

[0078] The present invention provides a laminated film that has excellent water and oil repellency and stain resistance. The laminated film of the present invention also has excellent transparency and is useful for applications such as packaging, coating, industrial use, and release materials.

Claims

1. A method for producing a laminated film having a coating layer on a resin substrate film, the coating layer containing polyester resin A and fine particles C whose surfaces have been hydrophobized, wherein the haze value of the laminated film is 10% or less, the water sliding angle is 10 degrees or more and less than 70 degrees, and in preparing a coating liquid for forming the coating layer, solvent B used at least when mixing polyester resin A and fine particles C whose surfaces have been hydrophobized satisfies the following conditions: The dispersion term, polarization term, and hydrogen bond term of the polyester resin A are respectively represented by δd １ , δp １ , δh １ , the interaction radius is R ０ The dispersion term, polarization term, and hydrogen bond term of the HSP value of the solvent B are respectively δd ２ , δp ２ , δh ２ The dispersion term, polarization term, and hydrogen bond term of the HSP value of the particle C whose surface has been hydrophobized are respectively δd ３ , δp ３ , δh ３ , the interaction radius is R １ In this case, the distance relationship between the substances is expressed by the following formulas (1) and (2). Relationship between the distance between the HSP values ​​of the polyester resin A and the solvent B (R Ａ－Ｂ ) ２ =4(δd ２ -δd １ ) ２ +(δp ２ -δp １ ) ２ +(δh ２ -δh １ ) ２ ・・・(1) Relationship between the distance between the HSP values ​​of the particles C whose surfaces have been hydrophobized and the solvent B (R Ｃ－Ｂ ) ２ =4(δd ２ -δd ３ ) ２ +(δp ２ -δp ３ ) ２ +(δh ２ -δh ３ ) ２ ・・・(2) In this case, the relative energy difference (RED), which is an index representing the affinity of the solvent B to the polyester resin A and the fine particles C whose surfaces have been hydrophobized, is expressed by the formulas (3) and (4), respectively. For example, the distance R between the HSP values ​​of the polyester resin A and the solvent B is Ａ－Ｂ is equal to the radius of the Hansen melting sphere of the polyester resin A (RED) ＡＢ =1. Relative Energy Difference (RED) ＡＢ = (R Ａ－Ｂ ) / R ０ ...(3) Relative Energy Difference (RED) ＣＢ = (R Ｃ－Ｂ ) / R １ ...(4) Solvent B having an HSP value within the range satisfying formula (5) is used as a solvent for polyester resin A and surface-hydrophobized fine particles C. The solvent may be a single solvent or a mixed solvent of multiple substances. (R Ａ－Ｂ ) / R ０ ≦1.5 and (R Ｃ－Ｂ ) / R １ ≦0.75 (5)

2. 2. The method for producing a laminated film according to claim 1, wherein the contact angle of the surface of the coating layer with decane is 40 degrees or more.

3. 3. The method for producing a laminated film according to claim 1, wherein the atomic composition ratio in a region 10 nm deep from the surface of the coating layer is determined by measurement using an X-ray photoelectron spectroscopy (ESCA), and the ratio of fluorine atoms is 20 at % or more.

4. 3. The method for producing a laminated film according to claim 1, wherein the average primary particle diameter of the fine particles C having hydrophobic surfaces is 30 nm to 500 nm.

5. 3. The method for producing a laminated film according to claim 1, wherein the resin substrate film is a polyethylene terephthalate film or a polyethylene naphthalate film.

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