JP6988491B2 - Laminated film and its manufacturing method - Google Patents

Description

The present invention relates to a laminated film having a resin layer on at least one surface of a thermoplastic resin film and a method for producing the same.

In recent years, with the spread of touch panels, the development of materials having a conductive function using metals such as indium tin oxide (ITO) and silver and carbon nanotubes (CNT) has been actively carried out. Among them, metal nanoparticles and CNTs are stable against heat and chemicals, and can be dispersed in water and various solvents by using a dispersant, so they are being actively studied as coating materials. ing.
In order to utilize the characteristics of metal nanoparticles and CNTs by coating, it is necessary to form a conductive network of metal nanoparticles and CNTs on the substrate. Therefore, the base material is required to have excellent coatability without repelling or uneven coating of the coating liquid containing conductive metal nanoparticles (conductive metal ink) or the coating liquid containing CNT (CNT dispersion). .. Further, as the required characteristics of the conductive film, the adhesiveness between the thermoplastic resin film as the base material and the conductive layer and the moisture-resistant heat adhesiveness are required. Therefore, in order to produce a film having excellent conductivity, an undercoat layer having excellent coatability and adhesion to a thermoplastic resin film is required for conductive metal inks and CNT dispersions. ..
For example, Patent Document 1 describes a technique relating to a polyester film for an inkjet printer, which has excellent adhesion to ink and weather resistance as an ink image receiving layer. Further, Patent Document 2 describes a film for an inkjet printer that has both adhesion to ink and water resistance. Further, in Patent Document 3, although the use is different, the structure is similar to that of Patent Document 1 and Patent Document 2, and the adhesiveness to the metal oxide is achieved by the coating film composed of the binder resin and the inert particles.

Japanese Patent Application Laid-Open No. 2003-7191 Japanese Unexamined Patent Publication No. 11-321074 Japanese Patent Application Laid-Open No. 2003-12841

However, in Patent Document 1, since the surface energy of the coating film is high, it is difficult to form an appropriate conductive network due to the aggregation of metal nanoparticles and CNTs when the conductive metal ink or the CNT dispersion is applied, and it is also moisture resistant. Thermal adhesion and water resistance tend to decrease. In Patent Document 2, the particle size of the inorganic particles contained in the ink receiving layer is large, and it is difficult to apply the inorganic particles to the optical film application in terms of transparency. Further, since the hydrophobic binder is used, the moisture resistance and heat adhesion and the water resistance are good, but contrary to Patent Document 1, the coating property of the conductive metal ink or the CNT dispersion is deteriorated. Patent Document 3 does not disclose technology relating to coatability with conductive metal inks or CNT dispersions because it is intended for packaging material applications, and is presumed to have the same surface energy as Patent Document 1 from the coating film composition, and has moisture and heat adhesion resistance. It is considered that the water resistance is likely to decrease.

The present invention has the following configuration. That is,
[I] A laminated film having a resin layer (X) containing a resin (B) having an alkyl group having 12 or more carbon atoms on at least one surface of the thermoplastic resin film, and the following (1) to ( 6 ). Laminated film, which meets
(1) The surface roughness Ra (center line average roughness) of the resin layer (X) is 5 nm or more and 100 nm or less.
(2) The surface energy of the resin layer (X) is 30 mN / m or more and 45 mN / m or less.
(3) The water contact angle of the resin layer (X) is 65 ° or more and 110 ° or less.
(4) The resin layer (X) contains the inorganic particles (A) and the polyester resin (C) having a hydrophilic functional group.
(5) The thermoplastic resin film is a polyester film.
(6) The resin (B) having an alkyl group having 12 or more carbon atoms is an acrylic resin having an alkyl group having 12 or more carbon atoms in a side chain.
[ II ] The laminated film according to [I] , wherein the inorganic particles (A) are colloidal silica.
[ III ] The laminated film according to [I] or [II] , wherein the surface zeta potential of the resin layer (X) is -50 mV or more and -10 mV or less.
[ IV ] The laminated film according to any one of [I] to [III ], which is used by further providing a processed layer on the surface of the resin layer (X) .
[ V ] The laminated film according to any one of [I] to [IV ] used as an undercoat film for a conductive coating material.
[ VI ] The resin layer (X) is formed from a coating composition containing inorganic particles (A), a resin (B) having an alkyl group having 12 or more carbon atoms, and a polyester resin (C) having a hydrophilic functional group. The polyester resin (C) having a hydrophilic functional group is synthesized from a dicarboxylic acid component raw material and a diol component raw material, and the dicarboxylic acid component raw material is a dicarboxylic acid having a sulfonic acid base and / or its own. ester-forming derivatives, 1 to 25 mol% including at least one selected from polyvalent carboxylic acid and / or an ester-forming derivative thereof having three or more carboxylate with respect to the total dicarboxylic acid component material [I] ~ The laminated film according to any one of [V],
[VII] the resin layer on at least one surface of the thermoplastic resin film (X) is provided a method for producing a laminated film which satisfies the following (1) to (3),
A coating composition containing inorganic particles (A), a polyester resin having a hydrophilic functional group (C), and a resin having an alkyl group having 12 or more carbon atoms (B ) was applied to at least one surface of the thermoplastic resin film. after heating, by stretching, seen including a step of allowed to form the resin layer (X),
The thermoplastic resin film is a polyester film.
A method for producing a laminated film, wherein the resin (B) having an alkyl group having 12 or more carbon atoms is an acrylic resin having an alkyl group having 12 or more carbon atoms in a side chain.
(1) The surface roughness Ra (center line average roughness) of the resin layer (X) is 5 nm or more and 100 nm or less.
(2) The surface energy of the resin layer (X) is 30 mN / m or more and 45 mN / m or less.
(3) The water contact angle of the resin layer (X) is 65 ° or more and 110 ° or less .
[VIII] wherein the polyester resin having a hydrophilic functional group (C) is synthesized from a dicarboxylic acid ingredient material and a diol component material, the dicarboxylic acid component raw material, dicarboxylic acids having a sulfonic acid salt, a dicarboxylic having a sulfonic acid salt At least one selected from an acid ester-forming derivative, a polyvalent carboxylic acid having three or more carboxylic acid bases, and an ester-forming derivative of a polyvalent carboxylic acid having three or more carboxylic acid bases, can be used as a whole dicarboxylic acid component raw material. method for producing a laminated film according to a polyester resin [VII] produced from raw materials including 1 to 25 mol% with respect to a.

The laminated film of the present invention relates to a laminated film having a resin layer having excellent adhesiveness to a thermoplastic resin film and particularly exhibiting excellent coatability when a CNT dispersion dispersed in an aqueous solvent is applied.

Hereinafter, the laminated film having the resin layer (X) containing the resin (B) having an alkyl group having 12 or more carbon atoms of the present invention will be described in detail.

(1) Resin layer (X) and laminated film The laminated film of the present invention has a resin layer (X) containing a resin (B) having an alkyl group having 12 or more carbon atoms on at least one surface of the thermoplastic resin film. It is a laminated film. The resin layer (X) of the present invention needs to have a surface roughness Ra (center line average roughness) of 5 nm or more and 100 nm or less, and more preferably 10 nm or more and 30 nm or less. When the surface roughness Ra (center line average roughness) is 5 nm or more, the surface area of the resin layer (X) containing the resin (B) having an alkyl group having 12 or more carbon atoms becomes large, and thus the conductivity described later. When a metal ink or a CNT dispersion is applied, the area that spreads wet can be increased and the coatability can be stabilized. Further, when the surface roughness Ra (center line average roughness) of the resin layer (X) is 5 nm or more, the CNT dispersant is adsorbed in the gaps between the surface irregularities of the resin layer and the irregularities between the inorganic particles (A). It is possible to develop good coatability. On the other hand, since the surface roughness Ra (center line average roughness) of the resin layer (X) is 100 nm or less, the resin layer (X) is not scraped when the conductive metal ink or the CNT dispersion is applied. Stable coatability can be maintained. On the other hand, if the surface roughness Ra (center line average roughness) of the resin layer (X) is larger than 100 nm, the resin layer (X) will be scraped off when the CNT dispersion is applied, and the transparency of the film will be reduced. It gets worse and the haze of the laminated film gets worse (rises).

The method for reducing the surface roughness Ra (center line average roughness) of the resin layer (X) of the present invention to 5 nm or more and 100 nm or less is not particularly limited, but for example, the inorganic particles (A) described later are used as a coating composition. Or a polyester resin (C) having at least two or more hydrophilic functional groups having different glass transition temperatures (Tg) is contained in the coating composition, and the coating composition is coated, heated and stretched on a thermoplastic resin film. Examples thereof include a method of forming a resin layer (X).

Further, the resin layer (X) of the present invention needs to have a surface energy of 30 mN / m or more and 45 mN / m or less, more preferably 35 mN / m or more and 40 mN / m or less. When the surface energy of the resin layer (X) is 30 mN / m or more, when the conductive metal ink or the CNT dispersion is applied, the application can be applied without repelling. On the other hand, since the surface energy of the resin layer (X) is 45 mN / m or less, when the conductive metal ink or the CNT dispersion is applied and the solvent is dried, the metal nanoparticles or the CNTs are formed on the resin layer (X). ) Appropriately aggregates to form a conductive network, so that good conductivity can be obtained.

Further, the resin layer (X) of the present invention needs to have a water contact angle of 65 ° or more and 110 ° or less, more preferably 80 ° or more and 100 ° or less. By setting the water contact angle of the resin layer (X) to 65 ° or more, when the conductive metal ink or the CNT dispersion is applied and the solvent is dried, the metal nanoparticles and the CNT are contained in the resin layer (X). By appropriately aggregating and forming a conductive network, not only good conductivity can be obtained, but also under high temperature and high humidity such as 60 ° C. and 90% RH, the resin layer (X) can be obtained. It is possible to suppress a decrease in moisture resistance and heat adhesion due to swelling and moisture absorption. On the other hand, by setting the water contact angle of the resin layer (X) to 110 ° or less, when the conductive metal ink or the CNT dispersion described later is applied onto the resin layer (X), the resin layer (X) becomes. In addition to the effect of surface roughness Ra (center line average roughness), it is possible to stably apply the CNT dispersion without coating repellent or coating unevenness.

The laminated film of the present invention preferably has a haze of 3.0% or less. It is more preferably 2.0% or less, still more preferably 1.5% or less. When coating unevenness or cracks occur in the resin layer (X), the transparency of the film deteriorates (haze increases). Further, when the resin layer (X) of the present invention contains the inorganic particles (A), the transparency of the film deteriorates (the haze increases) when the inorganic particles (A) aggregate. Further, when the polyester resin (C) having at least two or more hydrophilic functional groups having different Tg is used as the coating composition constituting the resin layer (X), the polyester resins may be incompatible with each other. When agglomeration or coating unevenness or cracks occur in the resin layer (X), the transparency of the film deteriorates (haze increases). Therefore, by setting the haze of the laminated film to 3.0% or less, the above-mentioned effect of the present invention can be exhibited in the resin layer (X). Further, when the haze of the laminated film is 3.0% or less, when it is used as an undercoat film for a conductive coating, it can be preferably used for applications requiring transparency such as a touch panel and electronic paper.

Taking advantage of its characteristics, the laminated film of the present invention is preferably used by further providing a processed layer on the surface of the resin layer (X). When a processed layer is provided on the surface of the resin layer (X), the laminated film of the present invention can stabilize the coatability of the processed layer, suppress repelling and coating unevenness of the paint, and form a stable layer. Is. Therefore, in particular, the laminated film of the present invention can be suitably used as an undercoat film for a conductive coating material. In the present invention, the conductive coating material means a metal nanoparticles exhibiting conductivity, a conductive metal ink in which metal oxide nanoparticles are dispersed in a solvent, a CNT dispersant, a CNT dispersion composed of a solvent, and the like. .. The conductive film coated with the conductive paint can be used as an electrode for a touch panel, electronic paper, or the like. The characteristics required for an undercoat film for a conductive paint are transparency, adhesiveness to a thermoplastic resin film as a base material, and moisture-resistant heat-adhesiveness.

Further, the undercoat film for the conductive paint also needs to have the applicability of the conductive paint. When a conductive paint is applied to the surface of a general thermoplastic resin film (for example, polyethylene terephthalate film), the conductive paint repels on the thermoplastic resin film or causes coating unevenness. If the conductive paint is not applied stably, the conductivity of the conductive coat layer is lowered. Further, the conductive paint often contains a dispersant for the purpose of dispersing the conductive material such as CNT in the paint, but since the dispersant is generally an insulating substance, the conductive paint is uniformly applied. Otherwise, the conductivity of the conductive layer may be reduced. By having the resin layer (X) having excellent coatability on the thermoplastic resin film, the laminated film of the present invention can suppress the repelling and coating unevenness of the conductive paint and form a stable conductive layer. .. Therefore, the laminated film of the present invention satisfies the above-mentioned required characteristics of the undercoat film for conductive coating materials. Therefore, the laminated film of the present invention can be suitably used as an undercoat film for a conductive coating material.

Further, the resin layer (X) of the laminated film of the present invention preferably has a surface zeta potential of −50 mV or more and −10 mV or less. More preferably, it is -50 mV or more and -20 mV or less. By setting the surface zeta potential of the resin layer (X) to -10 mV or less, the surface of the resin layer (X) is made polar, and the above-mentioned repelling and coating unevenness of the conductive paint are suppressed to form a uniform conductive layer. It is possible to make it. On the other hand, when the voltage is -50 mV or higher, it is possible to impart adhesiveness and moisture-resistant heat-adhesiveness between the thermoplastic resin film as a base material and the resin layer (X).

The method for adjusting the surface zeta potential of the resin layer (X) to -50 mV or more and -10 mV or less is not particularly limited. As a method of adjusting the surface zeta potential, the resin layer (X) is subjected to physical treatment such as discharge treatment such as corona treatment and plasma treatment and frame treatment, and chemical treatment such as acid treatment and alkali treatment to perform a resin layer (X). Anionic functional groups such as carboxyl groups and hydroxyl groups are introduced on the surface of X), and hydroxyl groups described later are added to a part or all of the surface of the inorganic particles (A) contained in the resin layer (X). Examples include the use of inorganic particles (AD) having the contained acrylic resin (D). A method of using inorganic particles (AD) having an acrylic resin (D) containing a hydroxyl group described later on a part or all of the surface of the inorganic particles (A) contained in the resin layer (X), a resin layer (X). ) Is subjected to discharge treatment such as corona treatment and plasma treatment because the surface zeta potential can be easily adjusted to -50 mV or more and -10 mV or less.
In the laminated film of the present invention, it is preferable that at least one surface layer is a resin layer (X).

(2) Inorganic particles (A)
The resin layer (X) of the present invention contains inorganic particles (A) . In particular, it is preferable that the inorganic particles (A) are contained in an amount of 3% by mass or more and 30% by mass or less with respect to the entire resin layer (X). The inorganic particles referred to in the present invention are particles made of a compound other than an organic compound, which has a covalent bond and whose smallest unit is a molecule composed of two or more kinds of atoms. Therefore, in the present invention, the metal oxide particles are included in the inorganic particles, but the metal particles are not included. By including the inorganic particles (A) in the coating composition forming the resin layer (X) in the above range, the resin layer (X) can obtain good coatability. The composition of the inorganic particles (A) that can be used in the present invention includes, for example, silica, colloidal silica, alumina, ceria, kaolin, talc, mica, calcium carbonate, barium sulfate, carbon black, zeolite, titanium oxide, and various metal oxidations. Fine particles made of material are preferable. In particular, inorganic colloidal particles are preferable, and colloidal silica is particularly preferable, from the viewpoints of particle hardness, heat resistance, and alkali adhesion resistance. Further, it is preferable that the -SiOH group and the -OH- ion are present on the surface of the colloidal silica and the electric double layer is formed in a negatively charged state. For example, the "Snowtex (registered trademark)" series manufactured by Nissan Chemical Industries, Ltd. and the "Cataroid (registered trademark)" series manufactured by JGC Catalysts and Chemicals Co., Ltd. are preferably used. When the above-mentioned colloidal silica is used as the inorganic particles (A), the inorganic particles (A) are well dispersed in the resin layer (X), and the surface roughness Ra (center line average roughness) of the resin layer (X) is obtained. Can be 100 nm or less.

The average primary particle size of the inorganic particles (A) is preferably 15 nm or more and 80 nm or less. When the average primary particle size of the inorganic particles (A) is less than 15 nm, the surface roughness Ra (center line average roughness) of the resin layer (X) becomes 5 nm or less, and the surface becomes too smooth, which will be described later. When a metallic metal ink or a CNT dispersion is applied, good coatability may be exhibited. When the average primary particle size of the inorganic particles (A) exceeds 80 nm, the surface roughness Ra (center line average roughness) of the resin layer (X) becomes 100 nm, and a conductive metal ink or a CNT dispersion is applied. At that time, the resin layer (X) may be scraped off. In addition, the transparency of the laminated film deteriorates. The average primary particle size in the present invention represents the particle size obtained by the measuring method described later.

(3) Resin having an alkyl group having 12 or more carbon atoms (B)
The resin (B) having an alkyl group having 12 or more carbon atoms in the present invention needs to have an alkyl group having 12 or more carbon atoms. The coating composition forming the resin layer (X) preferably contains 5% by mass or more and 25% by mass or less, and more preferably 8% by mass or more and 16% by mass or less.

By containing the resin (B) having an alkyl group having 12 or more carbon atoms in the resin layer (X) of the present invention, the surface energy of the resin layer (X) is 45 mN / m or less and the water contact angle is 65 ° or more. When a conductive metal ink or CNT dispersion is applied and the solvent is dried, the metal nanoparticles and CNTs appropriately aggregate in the resin layer (X) to form a conductive network. Therefore, good conductivity can be obtained. It is more preferable that the resin (B) has an alkyl group having 16 or more and 40 or less carbon atoms.

Resin where the number of carbon atoms of the present invention has 12 or more alkyl groups (B) is an acrylic resin having an alkyl group of 12 or more carbon atoms in the side chain. The acrylic resin having an alkyl group having 12 or more carbon atoms in the side chain is specifically an acrylic resin synthesized from an acrylic monomer having an alkyl group having 12 or more carbon atoms in the side chain or an alkyl group having 12 or more carbon atoms. Examples thereof include an acrylate compound of an acrylic monomer having a side chain and an acrylic monomer copolymerizable with the acrylic monomer. By setting the number of carbon atoms to 12 or more, a sufficient hydrophobic effect can be exhibited. The upper limit of the number of carbon atoms of the alkyl group is not particularly limited, but it is preferable that the number of carbon atoms is 25 or less because it is easy to produce.

(4) Polyester resin (C) having a hydrophilic functional group
The laminated film of the present invention has a coating composition in which the resin layer (X) contains inorganic particles (A), a resin (B) having an alkyl group having 12 or more carbon atoms, and a polyester resin (C) having a hydrophilic functional group. It is preferably a layer formed from an object. In the present invention, the polyester resin (C) having a hydrophilic functional group is a polyester resin obtained by using a dicarboxylic acid component raw material and a diol component raw material, and has a hydrophilic functional group at the end or side chain of the polyester resin. The polyester resin to have is shown. By using a polyester resin having a hydrophilic functional group, the hydrophilicity of the polyester resin can be enhanced, and the solubility or dispersibility in an aqueous solvent can be improved. Examples of the hydrophilic functional group include a sulfonic acid base and a carboxylic acid base. In order to contain a hydrophilic functional group in the polyester resin (C), it has a dicarboxylic acid having a sulfonic acid base, a diol and an ester-forming derivative thereof (a compound containing a sulfonic acid base), and three or more carboxylic acid bases. It can be obtained by using a polyvalent carboxylic acid and an ester-forming derivative thereof (a compound containing a trivalent or higher valent carboxylic acid base) as a raw material for a polyester resin.

Further, in the present invention, as the polyester resin (C) having a hydrophilic functional group, it is preferable to use two or more kinds of polyester resins having different Tg. In particular, when the difference in Tg of the polyester resin is 10 ° C. or higher, the surface of the resin layer (X) is uneven due to the difference in stretchability due to the difference in Tg by applying, heating and stretching on the thermoplastic resin film. The surface roughness Ra (center line average roughness) of the resin layer (X) can be 5 nm or more and 100 nm or less.

Examples of the dicarboxylic acid containing a sulfonic acid base and its ester-forming derivative include sulfoterephthalic acid, 5-sulfoisophthalic acid, 5-sodium sulfoisophthalic acid, 4-sulfoisophthalic acid, and alkali metal salts thereof and alkaline soil. Similar metal salts and ammonium salts can be used, but the present invention is not limited thereto.

Examples of the compound containing a polyvalent carboxylic acid base having a valence of 3 or more include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, and trimesin. Acids, 1,2,3,4-butanetetracarboxylic acids, 1,2,3,4-pentanetetracarboxylic acids and their alkali metal salts, alkaline earth metal salts and ammonium salts can be mentioned. It is not limited to these.

As the carboxylic acid component constituting the polyester resin, aromatic, aliphatic, alicyclic dicarboxylic acids, trivalent or higher valent carboxylic acids, and ester-forming derivatives thereof can be used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 5-sodium sulfoisophthalic acid, 1,4-naphthalenedicarboxylic acid, and ester-forming derivatives thereof. Can be used.

The content of the polyester resin (C) having a hydrophilic functional group in the coating composition of the present invention is preferably 60% by mass or more and 90% by mass or less, more preferably 90% by mass or less, based on the entire coating composition. It is 70% by mass or more and 85% by mass or less. If the content of the polyester resin (C) having a hydrophilic functional group is less than 60% by mass, good coatability cannot be obtained. The reason for this is that if the content of the polyester resin (C) having a hydrophilic functional group is small, the film-forming property when forming the resin layer (X) containing a large amount of the inorganic particles (A) is lowered, and the resin Not only cracks are generated in the layer (X), but also the inorganic particles (A) are scraped off when the conductive metal ink or the CNT dispersion is applied on the resin layer (X) and fall off from the resin layer (X). I presume that it will end up. On the other hand, even if the polyester resin (C) having a hydrophilic functional group exceeds 90% by mass, similarly good coatability cannot be obtained. The reason for this is that if the content of the polyester resin (C) having a hydrophilic functional group is too large, the content of the resin layer (X) of the inorganic particles (A) becomes relatively small, and the inorganic particles ( It is presumed that most of A) is buried in the polyester resin (C) having a hydrophilic functional group, and the surface roughness Ra (center line average roughness) of the resin layer (X) becomes 5 nm or less. ing. The polyester resin (C) having a hydrophilic functional group is synthesized from a dicarboxylic acid component raw material and a diol component raw material, and the dicarboxylic acid component raw material is a dicarboxylic acid having a sulfonic acid base and an ester of a dicarboxylic acid having a sulfonic acid base. At least one selected from a forming derivative, a polyvalent carboxylic acid having three or more carboxylic acid bases, and an ester-forming derivative of a polyvalent carboxylic acid having three or more carboxylic acid bases is 1 for the entire dicarboxylic acid component raw material. Polyester resin produced from a raw material containing ~ 25 mol% The polyester resin (C) having a hydrophilic functional group is synthesized from a dicarboxylic acid component raw material and a diol component raw material, and the dicarboxylic acid component raw material has a sulfonic acid base. At least selected from a dicarboxylic acid, an ester-forming derivative of a dicarboxylic acid having a sulfonic acid base, a polyvalent carboxylic acid having three or more carboxylic acid bases, and an ester-forming derivative of a polyvalent carboxylic acid having three or more carboxylic acid bases. It is preferable that one kind is 1 to 25 mol% with respect to the whole dicarboxylic acid component raw material. A dicarboxylic acid having a sulfonic acid base which is a hydrophilic functional group, an ester-forming derivative of a dicarboxylic acid having a sulfonic acid base, a polyvalent carboxylic acid having three or more carboxylic acid bases, and a polyvalent acid having three or more carboxylic acid bases. By setting at least one selected from the ester-forming derivatives of carboxylic acid to 1 mol% or more, it is possible not only to impart hydrophilicity to the polyester resin (C) containing a hydrophilic functional group, but also to make it an aqueous solvent. It can be dissolved or dispersed. Further, by reducing the content of the compound containing a sulfonic acid base which is a hydrophilic functional group and a polyvalent carboxylic acid base of trivalent or higher to 25 mol% or less, the polyester resin (C) which stably contains a hydrophilic functional group can be obtained. It can be produced by copolymerization.

As the glycol component of the polyester resin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol and the like are used. be able to.

The polyester resin (C) having a hydrophilic functional group can be produced, for example, as follows. For example, it is produced by subjecting a compound containing a dicarboxylic acid component, a glycol component, a sulfonic acid base or a polyvalent carboxylic acid base having a valence of 3 or more to an esterification reaction or an ester exchange reaction, followed by a polycondensation reaction. After the first step of esterifying reaction or ester exchange reaction between the dicarboxylic acid component and the glycol component, a compound containing a sulfonic acid base or a trivalent or higher polyvalent carboxylic acid base is added to the first step. It can be produced by a method or the like produced by a second-stage step of subjecting the reaction product to a polycondensation reaction. At this time, as the reaction catalyst, for example, an alkali metal, an alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, a titanium compound and the like can be used.

The polyester resin (C) having a hydrophilic functional group obtained by the above production method is dispersed or dissolved in a solvent to prepare a coating composition. Examples of the means for dispersing or dissolving the polyester resin (C) in an aqueous solvent include a method of dissolving or dispersing the polyester resin (C) in an aqueous solution of an alkaline compound such as aqueous ammonia, sodium hydroxide, potassium hydroxide, and various amines with stirring. .. In this case, a water-soluble organic solvent such as methanol, ethanol, isopropanol, butyl cellosolve, or ethyl cellosolve may be used in combination.

As a more preferable effect, the resin layer (X) of the laminated film of the present invention is also excellent in suppressing triboelectric charging when in contact with a metal roll. Due to this effect, an increase in the film potential during transportation in the post-processing process is suppressed, so that not only foreign matter entrainment can be suppressed, but also coating unevenness of the post-processing layer can be suppressed. In particular, this effect is suitable when the laminated film of the present invention is used as an undercoat film for a conductive coating material. When used as an undercoat film for a conductive paint, since the paint itself has a conductive material, it has not been conventionally considered that the processability is deteriorated by charging. However, the conductive paint often contains a dispersant for the purpose of dispersing a conductive material such as CNT in the paint, but since the dispersant is generally an insulating substance, it is triboelectricly charged by contact with a metal roll. It was found that when the film was applied to the film in which the above was generated, uneven coating may become a problem. As a result of diligent studies by the present inventors, it has been clarified that the above-mentioned problems can be solved by using the laminated film of the present invention as an undercoat film for a conductive coating material. As a preferable mode for exhibiting this effect, the resin layer (X) in contact with the metal roll has inorganic particles (A), a resin (B) having an alkyl group having 12 or more carbon atoms, and a hydrophilic functional group. It may contain a polyester resin (C).

(5) Thermoplastic Resin Film The thermoplastic resin film used in the laminated film of the present invention is a film formed of a thermoplastic resin. It is a general term for films that are melted or softened by heat, and is not particularly limited. Examples of thermoplastic resins include polyester resins, polypropylene resins, polyolefin resins such as polyethylene films, polylactic acid resins, polycarbonate resins, acrylic resins such as polymethacrylate resins and polystyrene resins, polyamide resins such as nylon resins, and polyvinyl chloride resins. Examples thereof include polyurethane resin, fluororesin, and polyphenylene resin. The thermoplastic resin used for the thermoplastic resin film may be a monopolymer or a copolymer polymer. Moreover, you may use a plurality of resins.

Typical examples of these thermoplastic resin films are polyester films, polyolefin films such as polypropylene films and polyethylene films, polylactic acid films, polycarbonate films, acrylic films such as polymethacrylate films and polystyrene films, polyamide films such as nylon, and poly. Examples thereof include vinyl chloride film, polyurethane film, fluorofilm, and polyphenylene sulfide film.

Of these, polyester films, polypropylene films, polyamide films and the like are preferable in terms of mechanical properties, dimensional stability, transparency and the like, and polyester films are particularly preferable in terms of mechanical strength and versatility.

Therefore, in the present invention, the polyester resin constituting the polyester film which is particularly preferably used as the thermoplastic resin film will be described in detail below.

First, polyester is a general term for polymers whose main chain is an ester bond, and is ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate. , Ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate and the like, and one having at least one constituent as a main constituent can be preferably used. Although only one of these constituents may be used or two or more thereof may be used in combination, ethylene terephthalate is particularly preferable when comprehensively judging quality, economy and the like. That is, in the present invention, it is preferable to use polyethylene terephthalate as the thermoplastic resin used for the thermoplastic resin film. Further, when heat or shrinkage stress acts on the thermoplastic resin film, polyethylene-2,6-naphthalate having excellent heat resistance and rigidity is particularly preferable. These polyesters may further contain a part of other dicarboxylic acid components and diol components, preferably 20 mol% or less.

The ultimate viscosity (measured in o-chlorophenol at 25 ° C.) of the polyester resin forming the thermoplastic resin film of the laminated film of the present invention described above is preferably 0.4 to 1.2 dl / g, more preferably 0. A range of 5.5 to 0.8 dl / g is suitable for carrying out the present invention.

The polyester film using the polyester is preferably biaxially oriented. The biaxially oriented polyester film is generally a polyester sheet or film in an unstretched state, which is stretched about 2.5 to 5 times in the longitudinal direction and the width direction orthogonal to the longitudinal direction, respectively, and then heat-treated to crystallize. Orientation is completed and shows a biaxial orientation pattern by wide-angle X-ray diffraction. If the thermoplastic resin film is not biaxially oriented, the thermal stability of the conductive film, particularly dimensional stability and mechanical strength, is insufficient, and the flatness is poor, which is not preferable.

Further, in the thermoplastic resin film, various additives such as antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, etc. Antistatic agents, nuclear agents and the like may be added to such an extent that the characteristics are not deteriorated.

The thickness of the thermoplastic resin film is not particularly limited and is appropriately selected depending on the intended use and type, but is usually preferably 10 to 500 μm, more preferably 38, from the viewpoint of mechanical strength and handleability. It is ~ 250 μm, most preferably 75 ~ 150 μm. Further, the thermoplastic resin film may be a composite film produced by coextrusion, or may be a film obtained by laminating the obtained films by various methods.

(6) Method for Forming Resin Layer (X) In the present invention, the resin layer (X) has the above-mentioned resin (B) having an alkyl group having 12 or more carbon atoms , inorganic particles (A), and a hydrophilic functional group. A coating composition containing a polyester resin (C) having ..

Further, in the present invention, it is preferable to use an aqueous solvent as the solvent. This is because the use of an aqueous solvent can suppress rapid evaporation of the solvent in the drying step, can form a uniform resin layer, and is excellent in terms of environmental load.

Here, the aqueous solvent is soluble in water or water and alcohols such as methanol, ethanol, isopropyl alcohol and butanol, ketones such as acetone and methyl ethyl ketone, and glycols such as ethylene glycol, diethylene glycol and propylene glycol. It refers to a mixture of an organic solvent in an arbitrary ratio. This is because the use of an aqueous solvent can suppress rapid evaporation of the solvent in the drying step, can form a uniform resin layer, and is excellent in terms of environmental load.

As a method for applying the coating composition to the thermoplastic resin film, either an in-line coating method or an off-coating method can be used, but the in-line coating method is preferable.

The in-line coating method is a method of applying in the process of manufacturing a thermoplastic resin film. Specifically, it refers to a method in which a thermoplastic resin is melt-extruded and then applied at an arbitrary stage from biaxial stretching to heat treatment and winding, and is usually obtained by melt-extruding and quenching. An amorphous unstretched (unaligned) thermoplastic resin film (A film), followed by a longitudinally stretched (uniaxially oriented) thermoplastic resin film (B film), or a further stretched in the width direction. It is applied to any of the biaxially stretched (biaxially oriented) thermoplastic resin films (C film) before the heat treatment.

In the present invention, the coating composition is applied to any of the above-mentioned A film, B film, or C film thermoplastic resin film before the crystal orientation is completed, and then the thermoplastic resin film is uniaxially or biaxially applied. It is preferable to adopt a method of stretching the film and heat-treating it at a temperature higher than the boiling point of the solvent to complete the crystal orientation of the thermoplastic resin film and providing a composition layer. According to such a method, the film formation of the thermoplastic resin film and the coating and drying of the coating composition (that is, the formation of the composition layer) can be performed at the same time, which is advantageous in terms of manufacturing cost. In addition, it is easy to make the thickness of the resin layer thinner in order to perform stretching after coating.

Among them, a method of applying a coating composition to a film (B film) uniaxially stretched in the longitudinal direction, then stretching in the width direction, and heat-treating is excellent. Compared to the method of biaxial stretching after coating on an unstretched film, the number of stretching steps is one less, so that defects and cracks in the resin layer are less likely to occur due to stretching, and a resin layer having excellent transparency and smoothness can be formed. Because.

On the other hand, the offline coating method is a film forming step on a film or A film after the A film is stretched uniaxially or biaxially and heat-treated to complete the crystal orientation of the thermoplastic resin film. This is a method of applying a coating composition in a separate step.

In the present invention, the resin layer is preferably provided by the in-line coating method because of the various advantages described above.

Therefore, the best method for forming the resin layer in the present invention is a method of applying an aqueous coating composition using an aqueous solvent onto a thermoplastic resin film by an in-line coating method and drying the mixture. .. More preferably, it is a method of in-line coating the coating composition on the B film after uniaxial stretching.

(7) Method for preparing a coating composition using an aqueous solvent The coating composition using an aqueous solvent contains the substances (A), (B) and (C) having water dispersibility or water solubility, and the aqueous solvent. Can be produced by mixing and stirring in any order at a desired solid content weight ratio. As a method of mixing and stirring, the container can be shaken by hand, a magnetic stirrer or a stirring blade can be used, ultrasonic irradiation, vibration dispersion and the like can be performed.

If necessary, various additives such as a cross-linking agent, a lubricant, an inorganic particle, an organic particle, a surfactant, and an antioxidant are added to the extent that the characteristics of the resin layer (X) provided by the coating composition are not deteriorated. You may.

In particular, a compound (E) selected from a melamine compound, an oxazoline compound, and a carbodiimide compound can be contained. The mass of the compound (E) is 20% by mass or less so as not to deteriorate the characteristics of the resin layer (X) when the total mass of (A), (B) and (C) is 100% by mass. Is preferable.

The melamine compound that can be used in the present invention needs to have at least one triazine ring and one or more methylol groups in one molecule. Specifically, as the melamine compound, a compound obtained by dehydrating and condensing a methylol melamine derivative obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol or the like as a lower alcohol to etherify them is preferable.

Examples of the methylolated melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine.

The oxazoline compound is not particularly limited as long as it has at least one oxazoline group or an oxazoline group per molecule, but an addition-polymerizable oxazoline group-containing monomer is preferable, 2-vinyl-2-oxazoline, 2-vinyl-. 4-Methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl -2-Oxazoline can be mentioned.

The carbodiimide compound is not particularly limited as long as it has at least one carbodiimide structure represented by the following formula (1) per molecule, but is 2 in one molecule in terms of moisture resistance and heat adhesion. Polycarbodiimide compounds having one or more are particularly preferred. In particular, a polymer-type isocyanate compound having a plurality of carbodiimide groups at the end or side chain of a polymer such as a polyester resin or an acrylic resin can be preferably used because the hardness of the resin layer is improved and the oligomer precipitation inhibitory property is improved.
−N = C = N− Equation (1)
Known techniques can be applied to the production of the carbodiimide compound, and it is generally obtained by polycondensing the diisocyanate compound in the presence of a catalyst. As the diisocyanate compound as a starting material of the polycarbodiimide compound, aromatic, aliphatic, alicyclic diisocyanates and the like can be used, and specifically, toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and cyclohexane diisocyanate can be used. , Isophorone diisocyanate, dicyclohexyldiisocyanate and the like can be used. Further, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound to the extent that the effect of the present invention is not lost, a surfactant may be added, or polyalkylene oxide, a quaternary ammonium salt of dialkylaminoalcohol, or hydroxy may be added. Hydrophilic monomers such as alkyl sulfonates may be added or used.

(8) Coating method As the coating method of the coating composition on the thermoplastic resin film, any known coating method, for example, a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a blade coating method, or the like is used. be able to.

(9) Method for Producing Laminated Film Next, the method for producing the laminated film of the present invention will be described by taking as an example a case where a polyethylene terephthalate (hereinafter abbreviated as PET) film is used as a thermoplastic resin film. It is not limited to this. First, the PET pellets are sufficiently vacuum-dried, then supplied to an extruder, melt-extruded into a sheet at about 280 ° C., and cooled and solidified to prepare an unstretched (unoriented) PET film (A film). This film is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially oriented PET film (B film). The coating composition of the present invention prepared to a predetermined concentration is applied to one side of this B film. At this time, the coated surface of the PET film may be subjected to surface treatment such as corona discharge treatment before coating. By performing a surface treatment such as a corona discharge treatment, the wettability of the coating composition to the PET film can be improved, the repelling of the coating composition can be prevented, and a uniform coating thickness can be achieved.

After coating, the end portion of the PET film is gripped with a clip and guided to a heat treatment zone (preheating zone) at 80 to 130 ° C., and the solvent of the coating composition is dried. After drying, it is stretched 1.1 to 5.0 times in the width direction. Subsequently, the crystals are led to a heat treatment zone (heat fixing zone) at 160 to 240 ° C. and heat-treated for 1 to 30 seconds to complete the crystal orientation.

(Characteristic measurement method and effect evaluation method)
The method for measuring the characteristics and the method for evaluating the effect in the present invention are as follows.

(1) Measurement of total light transmittance and haze Prepare three (three) square laminated film samples with a side of 5 cm. The sample is then left at 23 ° C. and 50% relative humidity for 40 hours. For each sample, use the turbidity meter "NDH5000" manufactured by Nippon Denshoku Kogyo Co., Ltd., and measure the total light transmittance by JIS "Test method of total light transmittance of plastic transparent material" (K7361-1, 1997 edition). ), Haze is measured by a method according to JIS "How to obtain haze of transparent material" (K7136 2000 version). The total light transmittance and haze values of each of the three points (three) are averaged to obtain the total light transmittance and haze values of the laminated film.

(2) Measurement of average primary particle size of inorganic particles (A) First, collodion (low-nitrized nitrocellulose with a concentration of 2% by mass) is dropped on the pure water surface, and the collodion thin film developed on the water surface is made of nickel as a support film. Paste on the 400 mesh grid of. Next, the inorganic particles dispersed in the solvent are dropped onto the grid, and the solvent is dried to prepare a sample for measurement. The obtained measurement sample is observed with a TEM (transmission electron microscope: H7100FA type manufactured by Hitachi, Ltd.) at a magnification of 10,000 to 1,000,000, and 10 photographs showing the entire inorganic particles are obtained. For the 10 points (10 pieces) of inorganic particles, read the longest side (diameter if on a true sphere) of each particle, average the measured values at 10 points, and average the primary particle size of the inorganic particles. And.

(3) Measurement of Surface Roughness Ra (Center Line Average Roughness) of Resin Layer First, the surface of the resin layer (X) of the laminated film is measured using a scanning probe microscope (Shimadzu, SPM9600). The cantilever uses a non-contact mode high resonance frequency type probe (NANOSENSORS model number PPP-NCHR) in a field of view of 1 μm × 1 μm, a scanning speed of 0.5 Hz, and a range of 512 × 512 pixels. Next, the obtained data is calculated and processed based on JIS B0601 (2001) of the JIS standard, and the surface roughness Ra (center line average roughness) is calculated.

(4) Calculation of Surface Energy of Resin Layer (X) First, the laminated film was left to stand in an atmosphere at room temperature of 23 ° C. and relative humidity of 65% for 24 hours. Then, under the same atmosphere, the contact angle of each of the four solutions of pure water, ethylene glycol, formamide, and diiodomethane was measured with respect to the resin layer with a contact angle meter CA-D type (manufactured by Kyowa Interface Science Co., Ltd.). ), 5 points are measured respectively. The contact angle of each solution is the average value of the measured values of the three points excluding the maximum value and the minimum value of the measured values of the five points.

Next, using the contact angles of the obtained four types of solutions, the "solid surface free energy (γ) of the solid surface free energy (γ) is distributed into the dispersion force component (γ _S ^d ) and the polar force component (γ _S ^p ). , and separated into three components of the hydrogen bond force component (gamma _S ^h), the geometric mean method based on equation (extended Fowkes equation) "which extends the Fowkes equation, dispersion force of the present invention, polar forces, hydrogen bonding forces and The surface energy, which is the sum of the dispersion force and the polarity force, is calculated.

A specific calculation method is shown. The meaning of each symbol is described below. gamma _S ^L when a tension at the interface of solid and liquid, Equation (1) is satisfied.

gamma _S ^L: surface energy of the known solution according to the resin layer and Table 1 gamma _S: the surface energy of the resin layer gamma _L: Known in Table 1 the surface energy gamma _S ^d of a solution: the surface energy of the resin layer dispersion force component gamma _S ^p: polar force component of the surface energy of the resin layer gamma _S ^h: hydrogen bonding component of the surface energy of the resin layer gamma _L ^d: dispersion force component of the known solutions the surface energy of the in Table 1 gamma _L ^p: Table 1 polar force component of the known solutions the surface energy of the gamma _L ^h according to: hydrogen bonding component of the known solutions the surface energy of the in Table ^{_{1 γ S L = γ S +}} γ L -2 (γ ^{_{S d · γ L d) 1/2}} -2 (γ S p · γ L p) 1/2 -2 (γ S h · γ L h) 1/2 ··· equation (1).

Further, the state when the smooth solid surface and the droplet are in contact with each other at the contact angle (θ) is expressed by the following equation (Young's equation).

^{_{γ S = γ S L + γ}} L cosθ ··· equation (2).

By combining these mathematical formulas (1) and (2), the following equation is obtained.
_{^{(γ S d · γ L d}} ) 1/2 + (γ S p · γ L p) 1/2 + (γ S h · γ L h) 1/2 = γ L (1 + cosθ) / 2 ··· formula (3).

In practice, the contact angles (θ) of the four solutions of water, ethylene glycol, formamide, and diiodomethane and the surface tension components of the known solutions shown in Table 1 (γ _L ^d , γ _L ^p , γ). _L ^h ) is substituted into the equation (3), and four simultaneous equations are solved. As a result, the solid surface energy (gamma), dispersion force component (γ _S ^d), polar force component (γ _S ^p), and hydrogen bonding force component (γ _S ^h) is calculated. Incidentally, the dispersion force of the present invention corresponds to the dispersion force component (γ _{S ^d),} polar forces of the present invention corresponds to the sum of the polar force component (γ _{S ^p)} and hydrogen bond force component (γ _{S ^h).}

(5) Evaluation of CNT coatability A CNT dispersion was prepared as follows. First, 0.1 mg of CNT (straight two-walled CNT: manufactured by Science Laboratory Co., Ltd., diameter 5 nm) and sodium carboxymethyl cellulose (Sigma-Aldrich Japan Co., Ltd.) (hereinafter abbreviated as CMC-Na) as a CNT dispersant were added to 0. 25 mg and 249.65 mg of water were placed in a 50 mL sample tube to prepare a CNT dispersion, and ultrasonically irradiated for 30 minutes using an ultrasonic crusher (VCX-502 manufactured by Tokyo Rikaki Co., Ltd., output 250 W, direct irradiation). Then, a uniform CNT dispersion (CNT concentration 0.04% by mass, CNT dispersant 0.10% by mass, (B) / (A) = 2.5) is obtained.

Next, the obtained CNT dispersion is applied onto the resin layer (X) of the laminated film using a bar coat so that the coating thickness is 6 to 10 μm. Next, the laminated film sample coated with the CNT dispersion was dried for 1 minute in a hot air oven "HIGH-TEMP-OVEN PHH-200" manufactured by Espec Co., Ltd. set at 100 ° C. (air volume gauge "7") to evaluate the sample. To get.

A4 size (210 mm x 300 mm) is separately applied to the obtained laminated film sample for the total light transmittance calculated from the visual application repelling, the presence or absence of coating unevenness, and the average value of the three points obtained in (1). The total light transmittance of 10 points is randomly measured and evaluated from the laminated film sample of. As the evaluation standard, the evaluation standard "B" is judged to be good CNT coatability.
A: The total light transmittance of any of the 10 points measured at random is a difference of less than 0.7% from the average value of the 3 points obtained by (1).
B: The total light transmittance of any of the 10 points measured at random is a difference of 0.7% or more and less than 1.0% with respect to the average value of the three points obtained in (1).
C: There is a difference of 1.0% or more in the total light transmittance of any of the 10 points measured at random with respect to the average value of the three points obtained in (1).
D: Coating repellent and coating unevenness are clearly confirmed visually.

(6) Adhesiveness evaluation In accordance with JIS5600-5-6 (established in 1999), a 5 × 5 25-square cut is made on the resin layer (X) surface of the laminated film with a cut interval of 2 mm. Next, rub Nichiban 18 mm cellophane tape (registered trademark) (product number: CT-18S) firmly on the cut portion with your finger so that the cut can be seen. Then, the cellophane tape (registered trademark) is momentarily peeled off at an angle of about 60 ° with respect to the resin layer. Count the number of cells peeled off. Even if only a part of the square is peeled off, it is counted as one square. The number of evaluations is 5, and the average value is calculated. The evaluation criteria are set as follows. Evaluation criteria "B" or higher are judged to be good adhesiveness.

A: The number of squares peeled is 0 squares B: The number of squares peeled exceeds 0 squares and is 3 squares or less C: The number of squares peeled exceeds 3 squares and is 5 squares or less D: The number of squares peeled is 5 squares Exceed.

(7) Evaluation of Moisture-Resistant Heat Adhesiveness In a constant-temperature and constant-humidity layer (LU-113 manufactured by Espec Co., Ltd.) in which the laminated film was set at 60 ° C. and 90% RH by the same method as in the previous section (6), 10 days (240 hours). ) It was stored statically. After 10 days, the sample was taken out from the constant temperature and humidity layer and allowed to stand and dry for 1 hour in a normal state (23 ° C., relative humidity 50%). After static drying, the adhesiveness is evaluated by the same method as in (5). As for the evaluation criteria, the evaluation criteria "B" or higher are judged to be good adhesiveness as in (5).

A: The number of squares peeled is 0 squares B: The number of squares peeled exceeds 0 squares and is 3 squares or less C: The number of squares peeled exceeds 3 squares and is 5 squares or less D: The number of squares peeled is 5 squares Exceed.

(8) Measurement of surface zeta potential of resin layer (X) First, the laminated film is sampled to 3 cm × 1 cm so as to match the size of the cell for measuring solid surface zeta potential, and the measurement surface is the resin layer (X) surface of the laminated film. Set in a zeta potential meter (manufactured by Otsuka Electronics Co., Ltd., using ELSZ-1000, Flat Surface Cell) and water as a solvent (temperature: 25 ° C., refractive index: 1.3328, viscosity: 0.8878). The measurement was carried out three times with (cP) and the dielectric constant: 78.3), and the average value of the three times of the values calculated by the equation of Smoluchowski was taken as the value of the zeta potential.

(9) Triboelectric charging with metal rolls (slipperiness with metal plates)
The triboelectric charge with the metal roll is evaluated by the slipperiness with the metal SUS plate. The laminated film is sampled to 5 cm × 20 cm, placed so that the resin layer (X) surface is in contact with the metal SUS plate, and ^{while applying a load of 200 g / cm 2} , it slides a distance of 5 cm in length and reciprocates until it stops. Evaluate by the number of times. The measurement was performed in an environment of 23 ° C. and 50% RH. As the evaluation standard, the evaluation standard "B" is judged to have good slipperiness.

A: 10 round trips or more B: 5 round trips or more and less than 10 round trips C: 3 round trips or more and less than 5 round trips D: Less than 3 round trips.

The present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples. Hereinafter, Example 9 will be referred to as a reference example.

(Example 1)
The paint composition was adjusted as follows.
Inorganic particles (A1):
Colloidal silica "Snowtex OL" (average primary particle size 45 nm, manufactured by Nissan Chemical Industries, Ltd.)
Resin having an alkyl group having 12 or more carbon atoms (B1):
500 parts by weight of toluene, 80 parts by weight of stearylmethacrylate (18 carbon atoms in the alkyl chain), 15 parts by weight of methacrylic acid, 5 parts by weight of 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. A part and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B1) having an alkyl group having 12 or more carbon atoms.
Polysell resin (C1) having a hydrophilic functional group:
First, 50 parts by mass of terephthalic acid, 50 parts by mass of isophthalic acid, 50 parts by mass of ethylene glycol, and 30 parts by mass of neopentyl glycol are purged with nitrogen together with 0.3 parts by mass of antimony trioxide and 0.3 parts by mass of zinc acetate, which are polymerization catalysts. The polymerization reaction was carried out at 190 to 220 ° C. for 12 hours under normal pressure while removing water to obtain polyester glycol. Next, 5 parts by mass of 5-sodium sulfoisophthalic acid was charged into the obtained polyester glycol, and xylene was charged into a reactor as a solvent, and polymerization was carried out for 3 hours while distilling off xylene at 260 ° C. under a reduced pressure of 0.2 mmHg. Then, a polysell resin (C1) having a hydrophilic functional group was obtained. This polyester resin (C1) was dissolved in an aqueous solvent containing aqueous ammonia and butyl cellulose to prepare an aqueous solution.
Aqueous solvent: pure water.

The coating composition was adjusted at the ratio shown in Table 2 with the total of (A1), (B1) and (C1) described above as 100 parts by mass. Further, in order to improve the coatability on the polyester film, a fluorine-based surfactant (Plus Coat (registered trademark) RY-2 manufactured by Mutual Chemical Co., Ltd.) is applied to a total of 100 parts by mass ((A1)) of the coating composition. ) + (B1) + (C1)) to 0.03 parts by mass to make paint 1.

Next, PET pellets (extreme viscosity 0.63 dl / g) containing substantially no particles were sufficiently vacuum-dried, then supplied to an extruder, melted at 285 ° C., extruded into a sheet from a T-shaped mouthpiece, and statically charged. Using the electric cast method, the particles were wound around a mirror casting drum having a surface temperature of 25 ° C. and cooled and solidified. This unstretched film was heated to 90 ° C. and stretched 3.4 times in the longitudinal direction to obtain a uniaxially stretched film (B film). This film was subjected to corona discharge treatment in air.

Next, the paint 1 was applied to the corona discharge-treated surface of the uniaxially stretched film using a bar coat. Grasp both ends of the uniaxially stretched film coated with the paint 1 with clips to guide it to the preheating zone, set the atmosphere temperature to 75 ° C, then use a radiation heater to set the atmosphere temperature to 110 ° C, and then set the atmosphere temperature. The coating composition was dried at 90 ° C. to form a composition layer. The laminated film was continuously stretched 3.5 times in the width direction in a heating zone (stretching zone) at 120 ° C., and then heat-treated in a heat treatment zone (heat-fixing zone) at 230 ° C. for 20 seconds to complete crystal orientation. Got In the obtained laminated film, the thickness of the PET film was 100 μm. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.

(Examples 2 to 3)
Example 1 except that the mass ratio of the inorganic particles (A1) in the coating composition was changed to the mass ratio of the resin (B1) having an alkyl group having 12 or more carbon atoms and the polysell resin (C1) having a hydrophilic functional group. A laminated film was obtained in the same manner as in the above. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to a thermoplastic resin film, moisture-resistant heat-adhesiveness, CNT coating property, and alkali-adhesive resistance.

(Examples 4 to 6)
The inorganic particles (A) were changed to inorganic particles (A2): colloidal silica "cataloid SI-80P" (average primary particle size 80 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.), and (A), (B), (C). ) Was changed as shown in the table, and a laminated film was obtained in the same manner as in Example 1. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.

(Example 7)
A laminated film was obtained in the same manner as in Example 4 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B2) having an alkyl group having 12 or more carbon atoms. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.
Resin having an alkyl group having 12 or more carbon atoms (B2):
500 parts by weight of toluene, 65 parts by weight of behenyl methacrylate (22 carbon atoms in the alkyl chain), 25 parts by weight of methacrylic acid, 10 parts by weight of 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. A part and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B2) having an alkyl group having 12 or more carbon atoms.

(Example 8)
A laminated film was obtained in the same manner as in Example 1 except that the polysell resin (C) having a hydrophilic functional group was changed to the polysell resin (C2) having a hydrophilic functional group. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.
Polysell resin (C2) having a hydrophilic functional group:
First, 50 parts by mass of dimethyl 2,6-naphthalenedicarboxylate, 50 parts by mass of a compound obtained by adding 2 mol of ethylene oxide to 1 mol of bisphenol S, and 30 parts by mass of 1,3-propanediol as a polymerization catalyst are trioxidized. The mixture was charged in a nitrogen-purged reactor with 0.3 parts by mass of antimony and 0.3 parts by mass of zinc acetate, and polymerized at 190 to 220 ° C. for 12 hours under normal pressure while removing water to obtain polyester glycol. Next, 5 parts by mass of dimethyl sodium 5-sulfoisophthalate was charged into the obtained polyester glycol, and xylene was charged into the reactor as a solvent, and xylene was distilled off at 260 ° C. under a reduced pressure of 0.2 mmHg for 3 hours. Polymerization was carried out to obtain a polysell resin (C2) having a hydrophilic functional group. This polyester resin (C1) was dissolved in an aqueous solvent containing aqueous ammonia and butyl cellulose to prepare an aqueous solution.

(Example 9)
Polysell resin (C) having a hydrophilic functional group is changed to polysell resin (C1, C2) having two hydrophilic functional groups without using inorganic particles (A), and (B1) / (C1) / ( A laminated film was obtained in the same manner as in Example 1 except that the mass ratio of C2) was changed as described in the table. The characteristics of the obtained laminated film are shown in the table. The Tg of C1 was 65 ° C. and the Tg of C2 was 90 ° C. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.

(Example 10)
A laminated film was obtained in the same manner as in Example 8 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B3) having an alkyl group having 12 or more carbon atoms. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.

Resin having an alkyl group having 12 or more carbon atoms (B3):
500 parts by weight of toluene, 65 parts by weight of lauryl methacrylate (12 carbon atoms in the alkyl chain), 25 parts by weight of methacrylic acid, 10 parts by weight of 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. A part and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B3) having an alkyl group having 12 or more carbon atoms.

(Example 11)
A laminated film was obtained in the same manner as in Example 8 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B4) having an alkyl group having 12 or more carbon atoms. The characteristics of the obtained laminated film are shown in the table. It was excellent in transparency such as haze and total light transmittance, and was also excellent in adhesiveness to PET film, moisture-resistant heat-adhesiveness, and CNT coating property.

Resin having an alkyl group having 12 or more carbon atoms (B4):
500 parts by weight of toluene, 65 parts by weight of henicosyl methacrylate (21 carbon atoms in the alkyl chain), 25 parts by weight of methacrylic acid, 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. 10 parts by weight and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B4) having an alkyl group having 12 or more carbon atoms.

(Comparative Examples 1 to 3)
A laminated film was obtained in the same manner as in Example 1 except that the composition ratios of (A), (B) and (C) in the coating composition were changed as shown in the table. The characteristics of the obtained laminated film are shown in the table. In Comparative Example 1, since the amount of the inorganic particles (A) was small, the surface roughness of the resin layer (X) was lowered and the coatability of the CNT dispersion was poor. On the other hand, in Comparative Example 2, since the amount of the resin having an alkyl group having 12 or more carbon atoms is small, the surface energy of the resin layer (X) is high, and the moisture-resistant heat adhesiveness and CNT coating property of the resin layer (X) are high. It was bad. Further, in Comparative Example 3, since the amount of the polyester resin (C) having a hydrophilic functional group was further increased as compared with Comparative Example 2, the water contact angle was lowered, and the moisture-resistant heat adhesiveness of the resin layer (X) was increased. And the CNT coatability became further poor.

(Comparative Example 4)
A laminated film was obtained in the same manner as in Example 4 except that the composition ratios of (A), (B) and (C) in the coating composition were changed as shown in the table. The characteristics of the obtained laminated film are shown in the table. In Comparative Example 4, the amount of the inorganic particles (A) was large and the surface roughness of the resin layer (X) was significantly increased, but the amount of the polyester resin (C) having a hydrophilic functional group was decreased, so that the resin layer was formed. The adhesiveness and moisture-resistant heat-adhesiveness of (X) were poor, and when the CNT dispersion was applied, the inorganic particles (A) were scraped off, resulting in poor coatability.

(Comparative Example 5)
A laminated film was obtained in the same manner as in Example 8 except that the composition ratios of (A), (B) and (C) in the coating composition were changed as shown in the table. The characteristics of the obtained laminated film are shown in the table. In Comparative Example 5, the amount of the resin (B2) having an alkyl group having 12 or more carbon atoms was large, the surface energy of the resin layer (X) decreased, and the water contact angle became high, so that the resin layer (X). ) Poor adhesiveness and moisture resistance and heat adhesiveness, and when the CNT dispersion was applied, the CNT dispersion was repelled and the coatability was poor.

(Comparative Example 6)
A laminated film was obtained in the same manner as in Example 8 except that the composition ratios of (A), (B) and (C) in the coating composition were changed as shown in the table. The characteristics of the obtained laminated film are shown in the table. In Comparative Example 6, since the amount of the resin (B2) having an alkyl group having 12 or more carbon atoms was large and the water contact angle of the resin layer (X) was high, the adhesiveness and moisture resistance of the resin layer (X) were high. The thermal adhesiveness was poor, and when the CNT dispersion was applied, the CNT dispersion was repelled and the coatability was poor.

(Comparative Example 7)
A laminated film was obtained in the same manner as in Example 8 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B6) having an alkyl group having less than 12 carbon atoms. The characteristics of the obtained laminated film are shown in the table. The haze was high and defective, and the adhesiveness to the PET film, the moisture-resistant heat-adhesiveness, and the CNT coatability were inferior.

Resin having an alkyl group having less than 12 carbon atoms (B6):
500 parts by weight of toluene, 65 parts by weight of butyl methacrylate (4 carbon atoms of alkyl chain), 25 parts by weight of methacrylic acid, 10 parts by weight of 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. A part and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B6) having an alkyl group having less than 12 carbon atoms.

(Comparative Example 8)
A laminated film was obtained in the same manner as in Example 8 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B7) having an alkyl group having less than 12 carbon atoms. The characteristics of the obtained laminated film are shown in the table. Since the resin (B7) has an alkyl group having less than 12 carbon atoms, the haze is poor, and the adhesiveness to the PET film, the moisture-resistant heat adhesiveness, and the CNT coatability are inferior.

Resin having an alkyl group having less than 12 carbon atoms (B7):
In a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser, 500 parts by weight of toluene, 65 parts by weight of hydroxypropyl methacrylate (6 carbon atoms of the alkyl chain), 25 parts by weight of methacrylic acid, 10 parts by weight of 2-hydroxyethyl methacrylate. A part by weight and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B7) having an alkyl group having less than 12 carbon atoms.

(Comparative Example 9)
A laminated film was obtained in the same manner as in Example 8 except that the resin (B) having an alkyl group having 12 or more carbon atoms was changed to the resin (B8) having an alkyl group having less than 12 carbon atoms. The characteristics of the obtained laminated film are shown in the table. The haze was high and defective, and the adhesiveness to the PET film, the moisture-resistant heat-adhesiveness, and the CNT coatability were inferior.

Resin having an alkyl group having less than 12 carbon atoms (B8):
500 parts by weight of toluene, 65 parts by weight of octylmethacrylate (8 carbon atoms of alkyl chain), 25 parts by weight of methacrylic acid, 10 parts by weight of 2-hydroxyethyl methacrylate in a temperature-adjustable reactor equipped with a stirrer, thermometer and condenser. A part and 1 part of azobisisobutyronitrile were placed in a dropping device and dropped at a reaction temperature of 85 ° C. for 4 hours to carry out a polymerization reaction. Then, it was aged at the same temperature for 2 hours to complete the reaction, and a compound as a release agent (C) was obtained. The obtained compound was dissolved in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve to prepare an aqueous solution containing a resin (B8) having an alkyl group having less than 12 carbon atoms.

An undercoat film for conductive paints because it has excellent adhesion to thermoplastic resin films and moisture and heat adhesion, and exhibits good coatability for conductive materials such as conductive metal inks and CNT dispersions. It can be preferably used as an undercoat of a transparent conductive film which is a touch panel or an electronic paper member.

Claims (8)

A laminated film having a resin layer (X) containing a resin (B) having an alkyl group having 12 or more carbon atoms on at least one surface of a thermoplastic resin film, which satisfies the following (1) to (6). the film.
(1) The surface roughness Ra (center line average roughness) of the resin layer (X) is 5 nm or more and 100 nm or less.
(2) The surface energy of the resin layer (X) is 30 mN / m or more and 45 mN / m or less.
(3) The water contact angle of the resin layer (X) is 65 ° or more and 110 ° or less.
(4) The resin layer (X) contains the inorganic particles (A) and the polyester resin (C) having a hydrophilic functional group.
(5) The thermoplastic resin film is a polyester film.
(6) The resin (B) having an alkyl group having 12 or more carbon atoms is an acrylic resin having an alkyl group having 12 or more carbon atoms in a side chain. The laminated film according to claim 1 , wherein the inorganic particles (A) are colloidal silica. The laminated film according to claim 1 or 2 , wherein the surface zeta potential of the resin layer (X) is -50 mV or more and -10 mV or less. The laminated film according to any one of claims 1 to 3 , which is used by further providing a processed layer on the surface of the resin layer (X). The laminated film according to any one of claims 1 to 4 , which is used as an undercoat film for a conductive coating material. The resin layer (X) is a layer formed of a coating composition containing inorganic particles (A), a resin (B) having an alkyl group having 12 or more carbon atoms, and a polyester resin (C) having a hydrophilic functional group. The polyester resin (C) having a hydrophilic functional group is synthesized from a dicarboxylic acid component raw material and a diol component raw material, and the dicarboxylic acid component raw material has a dicarboxylic acid having a sulfonic acid base and / or an ester-forming property thereof. Any of claims 1 to 5 , which contains 1 to 25 mol% of at least one selected from a derivative, a polyvalent carboxylic acid having three or more carboxylic acid bases, and / or an ester-forming derivative thereof, in an amount of 1 to 25 mol% based on the entire dicarboxylic acid component raw material. The laminated film described in Crab. A method for producing a laminated film satisfying the following (1) to (3), wherein a resin layer (X) is provided on at least one surface of the thermoplastic resin film.
A coating composition containing an inorganic particle (A), a polyester resin (C) having a hydrophilic functional group, and a resin (B) having an alkyl group having 12 or more carbon atoms was applied to at least one surface of the thermoplastic resin film. after heating, by stretching, seen including a step of allowed to form the resin layer (X),
The thermoplastic resin film is a polyester film.
A method for producing a laminated film, wherein the resin (B) having an alkyl group having 12 or more carbon atoms is an acrylic resin having an alkyl group having 12 or more carbon atoms in a side chain.
(1) The surface roughness Ra (center line average roughness) of the resin layer (X) is 5 nm or more and 100 nm or less.
(2) The surface energy of the resin layer (X) is 30 mN / m or more and 45 mN / m or less.
(3) The water contact angle of the resin layer (X) is 65 ° or more and 110 ° or less . The polyester resin (C) having a hydrophilic functional group is synthesized from a dicarboxylic acid component raw material and a diol component raw material, and the dicarboxylic acid component raw material is a dicarboxylic acid having a sulfonic acid base and an ester of a dicarboxylic acid having a sulfonic acid base. At least one selected from a forming derivative, a polyvalent carboxylic acid having three or more carboxylic acid bases, and an ester-forming derivative of a polyvalent carboxylic acid having three or more carboxylic acid bases is 1 for the entire dicarboxylic acid component raw material. The method for producing a laminated film according to claim 7 , which is a polyester resin produced from a raw material containing ~ 25 mol% .