White laminated polyester film

Abstract

The objective is to provide a laminated white polyester film that possesses properties such as adhesion of the coating layer to the substrate layer, adhesion to UV inks, stampability, and writeability. The solution is a white laminated polyester film having a coating layer composed of a coating layer forming composition on at least one side of a white polyester resin layer. The coating layer forming composition includes a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and an additive (D). The smoothness of the coating layer surface, measured using a Wang Yan smoothness meter, satisfies Equations 1, 2, and 3. 50≦P1≦150 (Equation 1) 50≦P6≦150 (Equation 2) P1 / P6≦1.8 (Equation 3) (Where P1 (mmH2O) represents the measured value of the Wang Yan smoothness when the coating layer is formed 1 hour after the preparation of the aforementioned coating layer forming composition, and P6 (mmH2O) represents the measured value of the Wang Yan smoothness when the coating layer is formed 6 hours after the preparation of the aforementioned coating layer forming composition.)

Description

Technical Field

[0001] This invention relates to a white laminated polyester film useful as various labels and cards, shipping documents, printer recording paper, etc., and to a white laminated polyester film having properties of coating adhesion to coatings, printability / adhesion to UV inks, stamping (imprinting) properties, and writeability. Prior Technology

[0002] [Background Technology] Compared to natural paper, white laminated polyester film not only has superior water resistance, moisture absorption dimensional stability, flatness, gloss and clarity of printed materials, but also excellent mechanical strength. Therefore, it is widely used as a synthetic paper to replace natural paper in fields such as packaging paper, labels, maps, posters, business cards and other cards, delivery slips, and recording paper for various printers.

[0003] For example, Patent Document 1 discloses a toner printing recording material having a toner easy-adhesion layer on a substrate layer. [Previous Technical Documents] [Patent Literature]

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-246750 Summary of the Invention

[0005] [The problem the invention aims to solve] In the recording material shown in Patent Document 1, many particles are used to give it writeability. Because many particles are used, there is a tendency to generate particle aggregates.

[0006] In recent years, the image quality of electronic devices has improved, placing even greater demands on the clarity of printed materials. If the recording material shown in Patent Document 1 is used for printing, the appearance clarity may be compromised due to the convex defects originating from particle aggregation. However, the applications of white laminated polyester films have broadened, and a single film is required to have both imprinting and writing properties, as well as good adhesion to various inks and toners; the addition of particles is therefore indispensable.

[0007] Furthermore, compositions that form coating layers using many particles are prone to producing particle agglomerates. Therefore, in industries such as manufacturing, it is ideal to continuously prepare the compositions for forming coating layers and form the coating film. Consequently, processing methods that store pre-prepared compositions and then perform coating film formation are not suitable, and there is also the problem of poor productivity due to the need to suppress agglomerate formation during coating film formation.

[0008] This invention was made against the backdrop of related prior art. Specifically, the object of this invention is to provide a laminated white polyester film that possesses imprinting and writing properties, adaptability to various inks and toners, and the ability to suppress protruding particles while also maintaining a clear appearance. Furthermore, this invention can suppress protruding particles and form a good coating even when there is a time difference between the preparation of the coating composition and the coating process. [Methods used to solve problems]

[0009] That is, the present invention comprises the following components.

[0010] [1] A white laminated polyester film, It has a coating layer composed of a coating layer forming composition on at least one side of the white polyester resin layer. The aforementioned coating layer composition includes a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and additives (D), and The smoothness of the aforementioned coating surface, as measured by the Wang Yan-style smoothness meter, satisfies Equations 1, 2, and 3.

[0011] 50≦P1≦150 (Equation 1) 50≦P6≦150 (Equation 2) P1 / P6≦1.8 (Equation 3) (In the formula, P1(mmH2O) represents the measured smoothness value of Wang Yanshi at the time of coating layer formation, 1 hour after the aforementioned coating layer composition was prepared.) P6 (mmH2O) represents the measured smoothness value of the coating layer at the time of coating layer formation, 6 hours after the preparation of the aforementioned coating layer composition.

[0012] [2] The white laminated polyester film described in [1] contains a polycarbonate structure and a branched structure of a urethane resin, and the content of the urethane resin having a polycarbonate structure and a branched structure in 100% by mass of all solid components of the coating layer forming composition is 3 to 12% by mass.

[0013] [3] The white laminated polyester film as described in [1] or [2] contains two or more types of inorganic particles (B), namely particles (B1) with an average particle size of 0.1 μm or more and less than 1.0 μm and particles (B2) with an average particle size of 1.0 μm or more and less than 10.0 μm, and the blending amount of B1 and B2 has the following relationship: B1 / B2 = 0.1 to 4.0; the content of inorganic particles (B) in the total solid components of the coating layer is 30 to 70% by mass.

[0014] [4] The white laminated polyester film described in any of [1] to [3], wherein the aforementioned functional resin composition (C) is a compound comprising at least one of polyester resin, acrylic / styrene copolymer resin and polymeric antistatic agent, and the content of functional resin (C) in all solid components of the coating layer is 15 to 50% by mass.

[0015] [5] The white laminated polyester film described in any of [1] to [4], wherein the aforementioned polymeric antistatic agent is a resin having at least a sulfonate.

[0016] [6] The white laminated polyester film described in any of [1] to [5], wherein the aforementioned sulfonate is an alkali metal sulfonate.

[0017] [7] The white laminated polyester film described in any of [1] to [6], wherein the surface resistivity (logΩ / □) of the coating layer of the aforementioned white laminated polyester film at 23°C and 65%RH is 14 or less.

[0018] [8] The white laminated polyester film described in any of [1] to [7] wherein the content of the aforementioned additive (D) in the total solid components of the coating layer is more than 0.01% by mass and less than 1.00% by mass. [9] The white laminated polyester film described in any of [1] to [8], wherein the aforementioned additive (D) contains an antifoaming agent as additive D1.

[0019]

[10] The white laminated polyester film described in any of [1] to [9], wherein the aforementioned additive (D) includes a mineral oil-based defoamer as additive D1. [Effects of the Invention]

[0020] The white laminated polyester film of this invention can improve the adhesion of the coating layer to the substrate layer and improve the adhesion of the coating layer to printing inks, such as UV printing inks. Furthermore, even after long-term processing, there are few protrusions due to particle aggregation, which can maintain excellent appearance clarity and also have imprintability and writeability. Implementation

[0021] [The form in which the invention is carried out] The present invention will now be described in detail.

[0022] This invention relates to a white laminated polyester film. It has a coating layer composed of a coating layer forming composition on at least one side of the white polyester resin layer. The aforementioned coating layer forming composition comprises a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and an additive (D), and The smoothness of the aforementioned coating surface, as measured by the Wang Yan-style smoothness meter, satisfies Equations 1, 2, and 3.

[0023] 50≦P1≦150 (Equation 1) 50≦P6≦150 (Equation 2) P1 / P6≦1.8 (Equation 3) (In the formula, P1(mmH2O) represents the measured smoothness value of Wang Yanshi at the time of coating layer formation, 1 hour after the aforementioned coating layer composition was prepared.) P6 (mmH2O) represents the measured smoothness value of the coating layer at the time of coating layer formation, 6 hours after the preparation of the aforementioned coating layer composition.

[0024] If this invention is applicable, it can impart excellent writeability to recording materials. For example, during writing, it can suppress damage and surface collapse caused by pressure from writing instruments. Furthermore, it has excellent abrasion resistance. It can further suppress ink bleeding during stamping, and in post-stamping and post-writing operations, it can suppress ink back-slipping and dirt accumulation on easily adhered surfaces, thus exhibiting excellent stamping and writeability. Moreover, in addition to exhibiting excellent writeability for various writing instruments such as ballpoint pens and pencils, it can ensure that the written text remains for a long time.

[0025] Furthermore, in addition to satisfying the requirements of imprintability, writeability, and adhesion to various inks and toners, the present invention also exhibits excellent adhesion between the coating layer and the substrate, which can suppress damage to the coating layer itself.

[0026] Furthermore, even after prolonged processing, it can suppress unevenness and defects originating from particle aggregates, thus maintaining excellent appearance clarity.

[0027] For example, because the present invention can suppress protruding foreign matter in particles, a good coating film can be formed even if there is a time difference between the preparation of the composition of the coating layer and the coating, thereby reducing the amount of waste in the composition of the coating layer.

[0028] (White polyester resin layer) The white polyester resin layer involved in this invention may be, for example, a polyester resin layer.

[0029] In this invention, the polyester resin constituting the polyester resin layer (also referred to as the polyester film substrate) includes, in addition to polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, and polypropylene terephthalate, a copolymer polyester resin obtained by replacing a portion of the diol component or dicarboxylic acid component of the aforementioned polyester resin with a copolymer component as follows. Examples of copolymer components include, for example, diol components such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, and polyolefin diol, and dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, sodium isophthalate, and 2,6-naphthalenedicarboxylic acid.

[0030] In this invention, the polyester resin suitable for use as a polyester film substrate is mainly selected from polyethylene terephthalate, polyethylene terephthalate, polyethylene butylene terephthalate, and polyethylene 2,6-naphthalenedicarboxylate. Among these polyester resins, polyethylene terephthalate is the most suitable from the perspective of balancing physical properties and cost. Furthermore, the polyester film substrate made of these polyester resins is preferably a biaxially oriented polyester film, which can improve chemical resistance, heat resistance, mechanical strength, etc.

[0031] The catalyst used for polycondensation in the manufacture of polyester resins is not particularly limited, but antimony trioxide is suitable due to its low cost and excellent catalytic activity. Furthermore, germanium compounds or titanium compounds are also preferred. Further preferred polycondensation catalysts include those containing aluminum and / or its compounds with phenolic compounds, those containing aluminum and / or its compounds with phosphorus compounds, and those containing aluminum salts of phosphorus compounds.

[0032] The polyester film used in this invention is preferably a biaxially aligned film from the perspective of practicality, such as strength and toughness.

[0033] The polyester film substrate can be either a single layer or a laminated structure, but a preferred embodiment is an A / B / A layer laminated structure, where layer A contains inorganic particles and layer B contains micropores. By placing the layer containing inorganic particles in layer A, which is the surface layer, the film's slip properties, i.e., maneuverability and concealment, can be improved. By making only the inner layer B contain micropores, the film's cushioning properties and surface strength can be ensured. The method of forming the laminated structure is not particularly limited, but from the viewpoint of manufacturing stability and processing costs, co-extrusion is preferred.

[0034] Furthermore, the polyester film used as the white polyester resin layer in this invention can be a single-layer structure or a multi-layer structure, but preferably, some or all of its layers are opaque. The optical density, representing the opacity of the polyester film, is 0.3 or higher, preferably 0.3 to 4.0, and particularly preferably 0.5 to 3.0. If the optical density is lower than 0.3, the printing effect will be unclear and poor when printing is performed on the surface of the obtained polyester coated film. Furthermore, if the optical density is 4.0 or lower, even better printing results can be expected.

[0035] The method for obtaining the optical density within the aforementioned range is not particularly limited, but it can be achieved by including inorganic particles or a thermoplastic resin incompatible with the polyester resin in the polyester resin. The content of these particles is not particularly limited, but in the case of inorganic particles, it is preferably 5-35% by weight, and more preferably 8-25% by weight, relative to the generated polyester. On the other hand, in the case of containing an incompatible thermoplastic resin, it is preferably 5-35% by weight, and more preferably 8-28% by weight, relative to the polyester. Furthermore, when both inorganic particles and a thermoplastic resin incompatible with the polyester resin are used, from the perspective of film strength, toughness, and film formation stability, the total amount is preferably 40% by weight or less relative to the polyester film.

[0036] The inorganic particles that may be contained in the white polyester resin layer are not particularly limited, but are preferably inorganic particles with an average particle size of 0.1 to 4.0 μm, and particularly preferably inorganic particles with an average particle size of 0.3 to 1.5 μm. Specifically, white pigments such as titanium dioxide, barium sulfate, calcium carbonate, and zinc sulfide are preferred, and these may also be mixed in. Furthermore, inorganic particles commonly found in films, such as silicon dioxide, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconium oxide, tungsten oxide, lithium fluoride, calcium fluoride, and calcium sulfate, may also be used.

[0037] Furthermore, while not specifically limited to thermoplastic resins incompatible with polyester resins, examples of resins that can be mixed with polyethylene terephthalate resins include polystyrene resins, polyethylene resins, polypropylene resins, polymethylpentene resins and other polyolefin resins, acrylic resins, phenoxy resins, polyphenylene oxide resins, and polycarbonate resins. Moreover, these thermoplastic resins can be mixed or modified. They can also be used in combination with the aforementioned inorganic particles. Furthermore, various whitening agents can be added as needed.

[0038] Furthermore, the polyester film used in this invention is preferably a polyester film containing micro-voids with an apparent density of 0.3~1.3 g / cm3.

[0039] In terms of balancing cushioning and surface peel strength, polyester films containing micro-voids are preferably those with a void stacking density of 0.20 voids / μm or higher, more preferably 0.25 voids / μm or higher, and even more preferably 0.30 voids / μm or higher. As a result, the obtained polyester coated films exhibit excellent print clarity and processing characteristics during printing. Here, the void stacking density (voids / μm) is defined by the formula: number of voids in the film thickness direction (voids) / film thickness (μm). From the perspective of void performance efficiency, the upper limit of this void stacking density is preferably 0.80 voids / μm, and even more preferably 0.55 voids / μm. Methods for adjusting this density to the above range include, but are not limited to, adjusting the amount or type of incompatible thermoplastic resin, viscosity, etc., using methods such as changing the screw shape of the extruder or setting a static mixer in the molten resin flow channel.

[0040] These polyester films containing micropores are particularly useful because the micropores in the film cause light scattering at the interface with the polyester matrix, thus increasing opacity and reducing the addition of the aforementioned inorganic particles. Furthermore, the presence of micropores makes the substrate film itself lighter, simplifying operation and resulting in significant economic benefits such as reduced raw material and transportation costs.

[0041] Regarding the method for obtaining such a polyester film containing micro-voids, known methods such as the following methods can be used: for a thermoplastic polyester resin as a matrix, a thermoplastic resin incompatible with the polyester resin as described above is compounded, so that the incompatible resin microparticles are dispersed in the polyester resin to obtain a sheet, and the sheet is extended at least in the uniaxial direction, thereby creating voids around the aforementioned incompatible resin microparticles.

[0042] Furthermore, the thickness of the obtained polyester film containing micro-voids is preferably 5 to 300 μm. In particular, the thickness of the polyester film containing micro-voids with a void stacking density of 0.20 voids / μm or higher is preferably 20 to 300 μm, and more preferably 40 to 250 μm.

[0043] The whiteness required for printing materials can be expressed using color values. Specifically, the L value (lightness index) is a measure of brightness; the higher the value, the whiter the material. Furthermore, a high b value (b-value) strengthens the yellow tint, while a low value strengthens the blue tint. In other words, a high L value and a low b value result in high whiteness, or a visually strong white tone. This improves the clarity during printing.

[0044] To improve adhesion to the coating layer, a corona treatment layer and / or an easy-bond layer may be provided on the surface of the substrate film, which is a white polyester resin layer. The method for forming the easy-bond layer is generally a coating method, specifically including gravure coating, kiss coating, immersion coating, spray coating, curtain coating, air knife coating, blade coating, and reverse roll coating. Regarding the timing of coating, any method can be used, such as coating before film stretching, coating after longitudinal stretching, or coating on the surface of the film after alignment treatment. However, for improving coating adhesion, the best method is an inline coating method where, after applying a coating liquid to at least one side of the substrate film stretched in the uniaxial direction using the aforementioned coating methods, it is further stretched in a direction perpendicular to the previous uniaxial stretching method.

[0045] The resin used for the easy-bonding layer is preferably composed of one, two, or three of the following: acrylic, polyester, and ethyl carbamate. A crosslinking agent may also be included in the coating composition for the easy-bonding layer, if necessary.

[0046] (Coating layer) The present invention relates to a white polyester resin layer having at least one side of a coating layer forming composition comprising a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and an additive (D).

[0047] Because of the coating layer of the present invention, the laminated polyester film of the present invention can possess all of the following properties: adhesion to the white polyester resin layer (substrate layer), adhesion to UV ink, stamping properties, writing properties, and printing clarity.

[0048] Furthermore, the thermosetting resin composition (A) contains at least a urethane resin having a polycarbonate structure and a branched structure, and the content of the aforementioned urethane resin having a polycarbonate structure and a branched structure in 100% by mass of all solid components of the coating layer forming composition is 3 to 12% by mass.

[0049] The coating layer is believed to be formed by the cross-linking of thermosetting resin composition (A), inorganic particles (B), functional resin composition (C), and additives (D) through a cross-linking agent, followed by curing. However, since it is difficult to represent the cross-linked chemical structure itself, it is presented as a coating layer consisting of thermosetting resin composition (A), inorganic particles (B), functional resin composition (C), and additives (D) that is then cured. The coating layer can be applied to both sides of the polyester film, or it can be applied to only one side of the polyester film, while a different type of resin coating layer is applied to the other side.

[0050] The following is a detailed explanation of the composition of the coating layer.

[0051] (Thermosetting resin composition (A)) The thermosetting resin composition (A) comprises, for example, an urethane resin having a polycarbonate structure and a branched structure. Due to the presence of such a thermosetting compound, the adhesion of the coating layer to the substrate layer can be improved, and the adhesion of the coating layer to printing inks, such as UV printing inks, can also be improved. Furthermore, excellent imprinting and writing properties can be achieved. In particular, in this invention, it is presumed that high smoothness is derived, for example, through the interaction between the additive (D) described later and the thermosetting resin composition (A) (e.g., the thermosetting compound described in this specification).

[0052] The urethane resin of this invention is preferably, for example, having urethane bond portions and branched structures derived from polycarbonate polyol and polyisocyanate components, and may further include chain elongating agents as needed. The branched structure referred to herein is a structure suitably introduced by having three or more terminal functional groups in any of the aforementioned raw material components constituting the molecular chain, thereby forming a branched molecular chain structure after synthesis and polymerization.

[0053] The urethane resin with a polycarbonate structure in this invention, based on its branched structure, preferably has a lower limit of 3 terminal functional groups in its molecular chain, and more preferably 4. If there are 3 or more, the coating strength of the coating layer can be improved. The urethane resin with a polycarbonate structure in this invention, based on its branched structure, preferably has an upper limit of 6 terminal functional groups in its molecular chain. If there are 6 or fewer, it is preferable that the resin can be stably dispersed in an aqueous solution. Since the resin can be dispersed in an aqueous solution, the environmental impact can be reduced.

[0054] When synthesizing and polymerizing the polycarbonate-structured urethane resin of the present invention, the lower limit of the mass ratio of polycarbonate polyol to polyisocyanate (mass of polycarbonate polyol / mass of polyisocyanate) is preferably 0.5, more preferably 0.6, further preferably 0.7, particularly preferably 0.8, and most preferably 1.0. A ratio of 0.5 or higher improves adhesion to UV inks. When synthesizing and polymerizing the polycarbonate-structured urethane resin of the present invention, the upper limit of the mass ratio of polycarbonate polyol to polyisocyanate is preferably 3.0, more preferably 2.2, further preferably 2.0, particularly preferably 1.7, and most preferably 1.5. A ratio of 3.0 or lower improves the film strength of the coating layer.

[0055] Regarding the polycarbonate polyol component used for synthesizing and polymerizing the polycarbonate-structured urethane resin of the present invention, it is preferable to use an aliphatic polycarbonate polyol with excellent heat resistance and hydrolysis resistance. Examples of aliphatic polycarbonate polyols include aliphatic polycarbonate diol and aliphatic polycarbonate triol, and aliphatic polycarbonate diol may be used suitably. For the purpose of synthesizing and polymerizing the urethane resin having a polycarbonate structure in this invention, examples of aliphatic polycarbonate diols include those obtained by reacting one or more diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentanediol, diethylene glycol, and dipropylene glycol with carbonates such as dimethyl carbonate, ethylene carbonate, and phosgene.

[0056] Regarding the average molecular weight of the polycarbonate polyols mentioned above in this invention, it is preferably 1000-3000. More preferably 1200-2900, and most preferably 1500-2800. If it is above 1000, the ink adhesion can be improved, which is preferable. If it is below 3000, the coating strength of the coating layer can be improved, and damage caused by the pressure of writing instruments can be suppressed.

[0057] Regarding the polyisocyanates used in the synthesis and polymerization of the polycarbonate-structured urethane resins of this invention, examples include: aromatic aliphatic diisocyanates such as xylylene diisocyanate, isoflavone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate, or polyisocyanates formed by pre-addition of these compounds with trimethylolpropane, etc. Using the aforementioned aromatic aliphatic diisocyanates, aliphatic diisocyanates, or aliphatic diisocyanates is preferable as it avoids yellowing. Furthermore, it does not form an excessively rigid coating, thus mitigating stress caused by the thermal shrinkage of the polyester film substrate, resulting in better adhesion.

[0058] Examples of chain elongating agents include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; polyols such as glycerin, trimethylolpropane, and neopentyl tetrol; and ethylenediamine, hexamethylenediamine, and piperazine. Diamines, monoethanolamine and diethanolamine, thiodiglycols, or water.

[0059] In order to form a branched structure in the urethane resin, the following method can be preferred: after setting an appropriate temperature and time to react the aforementioned polycarbonate polyol component, polyisocyanate, and chain elongator, a compound having a hydroxyl group or isocyanate group with three or more functions is added, and the reaction is further carried out.

[0060] Specific examples of compounds having three or more functional hydroxyl groups include caprolactone triol, glycerol, trimethylolpropane, glycerol, hexanetriol, 1,2,3-hexanetriol, 1,2,3-pentanetriol, 1,3,4-hexanetriol, 1,3,4-pentanetriol, 1,3,5-hexanetriol, 1,3,5-pentanetriol, and polyether triols. Regarding the aforementioned polyether triols, examples include compounds obtained by using one or more of the following as initiators: glycerol, trimethylolpropane, or other alcohols, or compounds having three active hydrogen atoms, such as diethylenetriamine, as initiators, and then performing addition polymerization on one or more monomers such as ethylene oxide, propylene oxide, butane oxide, amylene oxide, glycidyl ether, methyl glycidyl ether, tributyl glycidyl ether, and phenyl glycidyl ether.

[0061] Specifically, a compound having three or more isocyanate groups can be a polyisocyanate compound having at least three or more isocyanate (NCO) groups in one molecule. Examples of isocyanate compounds with three or more functions in this invention include: biuret forms, urate forms, and adducts obtained by modifying isocyanate monomers such as aromatic diisocyanates, aliphatic diisocyanates, arylaliphatic diisocyanates, and alicyclic diisocyanates having two isocyanate groups.

[0062] Examples of aromatic diisocyanates include 1,3-phenyl diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, and 4,4'-diphenyl ether diisocyanate.

[0063] Examples of aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-endenylpropyl diisocyanate, 2,3-endenylbutyl diisocyanate, 1,3-endenylbutyl diisocyanate, dodecanethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0064] Examples of aryl aliphatic diisocyanates include phenyl dimethyl diisocyanate, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylphenyl dimethyl diisocyanate, and 1,3-tetramethylphenyl dimethyl diisocyanate.

[0065] Alicyclic diisocyanates include, for example, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI, isoflavone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,4-bis(isocyanate methyl)cyclohexane, etc.

[0066] A biuret is a self-condensing compound formed by the self-condensation of isocyanate monomers, such as the biuret of hexamethylene diisocyanate.

[0067] Urea esters are trimers of isocyanate monomers, such as trimers of hexamethylene diisocyanate, isoflavone diisocyanate, and toluene diisocyanate.

[0068] An adduct is a compound with three or more functions, formed by reacting the aforementioned isocyanate monomer with a compound containing low-molecular-weight active hydrogen with three or more functions. Examples include compounds obtained by reacting trimethylolpropane with hexamethylene diisocyanate, compounds obtained by reacting trimethylolpropane with toluene diisocyanate, compounds obtained by reacting trimethylolpropane with phenyl diisocyanate, and compounds obtained by reacting trimethylolpropane with isoflavone diisocyanate.

[0069] Regarding chain elongating agents with three or more functional groups, the above-mentioned chain elongating agents, such as trimethylolpropane and neopentyl tetrol, are alcohols with three or more hydroxyl groups.

[0070] To impart water dispersibility to urethane resins, (copolymerized) sulfonic acid (salt) groups or carboxylic acid (salt) groups can be introduced into the urethane molecular backbone. For maintaining moisture resistance, the introduction of weakly acidic carboxylic acid (salt) groups is suitable. Alternatively, nonionic groups such as polyoxyalkylene groups can also be introduced.

[0071] To introduce carboxylic acid (salt) groups into urethane resins, polyol compounds containing carboxylic acid groups, such as dimethylolpropionic acid and dimethylolbutyric acid, which are polyol components, are introduced as copolymerizing agents, and neutralization is achieved by using a salt-forming agent. Specific examples of salt-forming agents include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, and tri-n-butylamine, as well as N-methylamines. porphyrin, N-ethyl N-alkyl phyllates, etc. Phosphates, N-dimethylethanolamine, N-diethylethanolamine, and other N-dialkylalkanolamines. These can be used alone or in combination of two or more.

[0072] To impart water dispersibility, when using a polyol compound with a carboxylic acid (salt) group as a copolymer component, if the total polyisocyanate content of the urethane resin is set to 100 moles, the mole percentage of the polyol compound with a carboxylic acid (salt) group in the urethane resin is preferably 3 to 60 moles, more preferably 5 to 40 moles. A mole percentage of 3 moles or more provides better water dispersibility. Furthermore, a mole percentage of 60 moles or less maintains water resistance and provides better resistance to damp heat.

[0073] The urethane resin of the present invention is preferably one that has a terminal isocyanate structure to improve its strength. The terminal isocyanate structure may also be included in the branched structure.

[0074] The lower limit of the boiling point of the isocyanate-terminated capping agent for the urethane resin is preferably 150°C, more preferably 160°C, further preferably 180°C, particularly preferably 200°C, and most preferably 210°C. The higher the boiling point of the capping agent, the more its volatilization is suppressed, even during the drying step after coating or the film-forming step in online coating methods, and the more it suppresses the formation of minor coating surface unevenness. The upper limit of the boiling point of the capping agent is not specifically limited, but from a productivity perspective, it is considered to be around 300°C. Since boiling point is related to molecular weight, it is preferable to use a capping agent with a larger molecular weight to increase the boiling point of the capping agent; the molecular weight of the capping agent is preferably 50 or higher, more preferably 60 or higher, and further preferably 80 or higher.

[0075] The upper limit of the dissociation temperature of the capping agent is preferably 180°C, more preferably 160°C, further preferably 150°C, and most preferably 120°C. The capping agent dissociates from its functional groups due to heating during the drying step after coating or during the film-forming step in online coating methods, generating regenerated isocyanate groups. Therefore, the crosslinking reaction proceeds, and adhesion is improved. When the dissociation temperature of the capping isocyanate is below the above-mentioned temperature, the dissociation of the capping agent proceeds sufficiently, thus adhesion, especially resistance to damp heat, becomes good.

[0076] Regarding the end-capping agents used in the end-capping isocyanate of this invention, those with a dissociation temperature below 120°C and a boiling point above 150°C include bisulfite compounds such as sodium bisulfite; pyrazole compounds such as 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 4-nitro-3,5-dimethylpyrazole; active methylene compounds such as malonate (dimethyl malonate, diethyl malonate, di-n-butyl malonate, and di-2-ethylhexyl malonate); and methyl ethyl ketone. Triazole compounds such as 1,2,4-triazole are also suitable. Among these, pyrazole compounds are preferred in terms of resistance to damp heat and yellowing.

[0077] Of the total solid components (100% by mass) of the coating layer forming composition, 3-12% by mass comprises an urethane resin having a polycarbonate structure and a branched structure. Preferably, it is 4-11.5% by mass, more preferably 4.5-11% by mass. If it contains 3% or more by mass, the adhesion to UV printing inks and the hardness of the coating layer become good. Furthermore, if it is 12% or less by mass, the adhesion to the substrate film and the stamping properties are improved, which is preferable.

[0078] In this invention, in particular, by including a polycarbonate structure and a branched structure of urethane resin within such a range, the coating layer can obtain a film strength that can withstand various writing forms, further suppress bleeding during stamping, and suppress ink backing and dirt on easily adhered surfaces during stamping and writing operations.

[0079] Although the mechanism is not analyzed here, the printability tends to be improved because the polycarbonate and branched structure of the urethane resin exceeds 4% by mass.

[0080] Furthermore, the thermosetting resin composition (A) can be used in combination with urethane resins having polycarbonate and branched structures to include thermosetting acrylic resins. Azoline compounds, melamine compounds, carbodiimide compounds, epoxy resins, ester resins, alkyd resins, and urethane resins other than the aforementioned urethane resins. From the perspective of improving surface hardness, acrylic resins are preferred. Azoline compounds, melamine compounds, and carbodiimide compounds. Acrylic resins are preferred. Azoline compounds, melamine compounds, and carbodiimide compounds are particularly well-suited for use. Among the zozoline compounds, melamine compounds, and carbodiimide compounds, melamine compounds are preferred.

[0081] Examples of thermosetting acrylic resins include those with hydroxyl, hydroxymethyl, hydroxyethyl, hydroxybutyl, alkoxymethyl, alkoxyethyl, alkoxybutyl, epoxy, imino, etc., in the main chain and / or side chains, but are not limited to these.

[0082] So-called thermosetting type Azoline compounds are compounds that have intramolecular properties Compounds containing an oxazolinyl group, particularly preferably compounds containing an oxazolinyl group. Polymers with zoline groups can be polymerized by containing addition polymerizable elements. It is made by polymerizing a zolyl monomer alone or with other monomers. It exhibits addition polymerization properties. Monomers with an oxazolinyl group include 2-vinyl-2- Azoline, 2-vinyl-4-methyl-2- Azoline, 2-vinyl-5-methyl-2- Azoline, 2-isopropenyl-2- Azazoline, 2-isopropenyl-4-methyl-2- Azazoline, 2-isopropenyl-5-ethyl-2- Azoline, etc., may be used in mixtures of one or more of these. Among these, 2-isopropenyl-2- Azoline is also readily available and suitable for industrial applications. Other monomers, as long as they can react with monomers containing addition polymerization properties, are also suitable. There are no restrictions on the monomers used for copolymerization of zolyl monomers. Examples include: alkyl methacrylates (in terms of alkyl groups, these include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tributyl, 2-ethylhexyl, cyclohexyl) and other methacrylates; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and their salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; and (meth)acrylamide, N-alkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide, etc. Unsaturated amides such as acrylamide (in terms of alkyl groups, these include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tributyl, 2-ethylhexyl, cyclohexyl, etc.); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogenated α,β-unsaturated monomers such as vinyl chloride and vinylidene chloride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene, etc., can be used. Furthermore, a catalyst can be used to enhance reactivity.

[0083] The aforementioned melamine compound refers to a compound containing a melamine backbone. Examples include: alkylolized melamine derivatives; compounds obtained by partially or completely etherifying an alcohol with an alkylolized melamine derivative; and mixtures thereof. For the alcohol used in etherification, methanol, ethanol, isopropanol, n-butanol, isobutanol, etc., are suitable. Furthermore, the melamine compound can be a monomer, a polymer of two or more monomers, or a mixture thereof. Moreover, compounds containing a portion of melamine co-condensed with urea, etc., can also be used, and a catalyst can be used to enhance the reactivity of the melamine compound.

[0084] Thermosetting carbodiimide compounds can be synthesized using conventional techniques, generally through the condensation reaction of diisocyanate compounds. The diisocyanate compounds are not particularly limited; both aromatic and aliphatic compounds can be used. Examples include toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenyl diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isoflavone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate. Catalysts may also be used to enhance reactivity.

[0085] Of the total solid components (100% by mass) of the coating layer forming composition, the aforementioned thermosetting resin composition (A) preferably contains 4 to 27% by mass. If it is 4% by mass or more, there is no risk of inorganic particle shedding, which is preferable. Furthermore, if it is 4% by mass or more, the coating layer hardens sufficiently and has good abrasion resistance. If it is 27% or less, adhesion to the substrate film can be maintained, which is preferable.

[0086] (Inorganic particles (B)) Examples of inorganic particles (B) used in the coating layer in this invention include silicon dioxide, kaolin, talc, calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, and titanium oxide, but are not limited to these. Among these, silicon dioxide and calcium carbonate are particularly preferred.

[0087] These inorganic particles are preferably a combination of two or more types: particles with an average particle size of 0.1 μm to less than 1.0 μm (B1) and particles with an average particle size of 1.0 μm to less than 10.0 μm (B2). By combining particles within the above range, the surface roughness and maximum protrusion height of the coating layer can be adjusted to the desired range.

[0088] Regarding the mass ratio of B1 to B2, a B1 / B2 ratio of 0.1 to 4.0 is preferred, and a further preferred ratio of 0.2 to 3.5 is preferred. If the B1 / B2 ratio is within the range of 0.1 to 4.0, the surface roughness and maximum protrusion height are adjusted to the desired range, resulting in good imprintability and writeability. Furthermore, if the B1 / B2 ratio is within the range of 0.2 to 3.5, the imprintability and writeability become more clearly readable. The shape of the particles used is not particularly limited; any shape such as spherical, blocky, rod-shaped, or flat can be used. Furthermore, there are no particular restrictions on their hardness, specific gravity, color, etc.

[0089] While it should not be interpreted as a specific theory, the use of particles, by maintaining a B1 to B2 mass ratio within this range, allows for a difference in strength compared to films formed solely from resin, for example. Furthermore, it can suppress breakage and surface denting caused by pressure from writing instruments during writing. Moreover, it exhibits excellent abrasion resistance.

[0090] In a single sample, the mass ratio of B1 to B2 can be greater than 1.0 and less than 4.0, or greater than 1.0 and less than 3.5. Because the amount of particles (B1) is greater than the amount of particles (B2), good writeability can be imparted to the recording material.

[0091] While it shouldn't be interpreted as a specific theory, by maintaining a B1 to B2 mass ratio within this range, ink drying and adhesion can be achieved in a shorter time. For example, it can further suppress ink bleeding during stamping and inhibit ink backing and staining of easily adhered surfaces during stamping and writing, resulting in excellent stamping and writing properties. Furthermore, in addition to exhibiting excellent writing properties for various writing instruments such as ballpoint pens and pencils, it allows the written text to remain for a long time.

[0092] Inorganic particles (B) can also be surface-treated using organic compounds or silicon compounds having an organic moiety within the molecule. In particular, when using non-water-soluble media, it is suitable to use inorganic particles (B) that have already undergone surface treatment with organic materials.

[0093] Inorganic particles (B) can also be used in conjunction with organic particles. Examples of organic particles include benzoguanidine particles, cross-linked polystyrene particles, and cross-linked acrylic particles.

[0094] The content of inorganic particles (B) in the total solid components of the coating layer is preferably 30-70% by mass. If it is below 30% by mass, the sealability will deteriorate, and if it is above 70% by mass, there is a concern about particle shedding.

[0095] Furthermore, when particles (B1) and (B2) are included together, the total number of these particles falls within the aforementioned range. For example, the content of inorganic particles (B) is 35-65% by mass.

[0096] In a single-state sample, particles (B1) and (B2) can each contain multiple particles within a range that meets the specified particle size and other conditions. For example, particle (B1) can contain particles of different sizes within the range of (B1).

[0097] Inorganic particles (B) can be directly added to a coating obtained by adjusting the thermosetting resin composition (A), the functional resin composition (C), and the aqueous medium. However, in order to eliminate coarse inorganic particles and obtain the desired dispersed particle size, it is preferable to perform a dispersion step after adding the inorganic particles. Furthermore, it is even more preferable to first prepare a master batch of inorganic particles in order to obtain the desired dispersed particle size in a short time. Examples of methods for dispersing inorganic particles include ball mills, sand mills, grinding mills, roller mills, agitators, colloid mills, ultrasonic homogenizers, homogenizers, dissolvers, bead mills, wet jet mills, paint shakers, butterfly mixers, planetary mixers, and Henschel mixers. Regarding the average particle size after dispersion, the 50% volume average diameter (Dv50) is preferably 0.05~0.5 μm. If Dv50 is below 0.05 μm, Ra and S will become too small. Furthermore, if Dv50 is above 0.5 μm, Ra will become too large.

[0098] (Functional Resin Composition (C)) The functional resin composition (C) used in this invention completes the task of supplementing the properties of the thermosetting resin composition (A), such as improving printability, stampability, and mechanical strength. That is, in this invention, the effects of the thermosetting resin composition (A) can be achieved by including both the thermosetting resin composition (A) and the functional resin composition (C).

[0099] The functional resin composition (C) can be selected within a range that does not hinder the effect achieved by the thermosetting resin composition (A), and examples include polyester resin, polyurethane resin, polystyrene resin, and acrylic resin. Furthermore, these resins can be used in combination, or copolymers of these resins can be used. Mixtures with other resins can also be used. Examples include urethane / acrylic copolymer resin and acrylic / styrene copolymer resin. Other examples of the functional resin composition (C) include polymeric antistatic agents. From the viewpoint of improving the adhesion between the film and the coating layer, polyester resin is preferred. Furthermore, from the viewpoint of improving adhesion to UV inks and toner, acrylic / styrene copolymer resin is preferred. In other cases, to impart antistatic properties to the film, a polymeric antistatic agent is preferred as the functional resin composition (C). Because it possesses antistatic properties, it can prevent overlapping transmission (re-transmission) during printing and prevent the adhesion of foreign objects, dust, etc., so it is superior.

[0100] For example, the content of functional resin (C) in the total solid components of the coating layer is 15-50% by mass, or 20-45% by mass. By containing polyester resin in such an amount, the adhesion between the coating layer and the substrate layer can be improved. Furthermore, ideally, the resin composition should contain the most polyester resin.

[0101] (Polyester resin) The polyester resin used to form the coating layer in this invention can be linear, but it is more preferably a polyester resin composed of dicarboxylic acids and diols with branched structures. The dicarboxylic acids referred to herein include, in addition to terephthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid. Furthermore, the so-called branched glycols are diols having branched alkyl groups, such as 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2-butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, and 2,2-di-n-hexyl-1,3-propanediol.

[0102] The polyester resin contains, preferably, at least 10 mol% of the glycol component of the aforementioned preferred form, and more preferably at least 20 mol% of the total glycol composition. If the content is less than 10 mol%, the crystallinity becomes high, which may sometimes reduce the adhesion of the coating layer. The upper limit of the total glycol content is preferably less than 80 mol%, and more preferably 70% by mass. If it is more than 80 mol%, the concentration of oligomers as byproducts increases, which may sometimes affect the transparency of the coating layer. Regarding the glycol component other than the aforementioned compounds, ethylene glycol is preferred. If in small amounts, diethylene glycol, propylene glycol, butanediol, hexanediol, or 1,4-cyclohexanediethanol may also be used.

[0103] Regarding the dicarboxylic acid that forms a component of the aforementioned polyester resin, terephthalic acid or isophthalic acid is preferred. More preferably, in addition to the aforementioned dicarboxylic acid, 5-sulfonoisophthalic acid, etc., can be copolymerized in a range of 1 to 10 mol% to impart water dispersibility to the copolymer polyester resin. Examples include sulfonoterephthalic acid, 5-sulfonoisophthalic acid, and 5-sodium sulfonoisophthalic acid. Polyester resins containing dicarboxylic acids with a naphthalene skeleton can also be used, but to suppress the reduction in adhesion to UV printing inks, the proportion of such dicarboxylic acids is preferably less than 5 mol% of the total carboxylic acid content, or it may be omitted.

[0104] For example, in the case of a coating containing polyester resin, the content of functional resin (C) in the total solid components of the coating layer is 15-50% by mass, or 15-30% by mass. By containing polyester resin in such an amount, the adhesion between the coating layer and the substrate layer can be improved.

[0105] (Acrylic / styrene copolymer resin) The acrylic / styrene copolymer resin used in this invention is a polymer in which acrylic monomers and styrene monomers are alternately or randomly contained in the constituent units. Preferably, this acrylic / styrene copolymer resin contains 0.1% to 15% by mass of the total solid content of the coating layer composition out of 100% by mass. More preferably, it contains 3% to 15% by mass. If it is 0.1% by mass or more, the adhesion to UV inks and toners is improved, which is preferable. Furthermore, if it is 3% by mass or more, the adhesion to UV inks and toners is further improved, which is preferable. Furthermore, if it is 15% by mass or less, the adhesion to the coating, as well as the imprintability and antistatic properties, are not deteriorated, which is preferable.

[0106] (Polymer-type antistatic agent) The so-called polymeric antistatic agents used in this invention are polymeric compounds formed by introducing hydrophilic units into the molecule as conductive units. Depending on the conductive units (hydrophilic units) introduced, they are classified into nonionic polymeric antistatic agents (polyether ester amide system, ethylene oxide-epimerol system, polyether ester system), anionic polymeric antistatic agents (polystyrene sulfonic acid system), and cationic polymeric antistatic agents (acrylate polymer system containing quaternary ammonium salt groups).

[0107] In this invention, anything known can be used as long as the water dispersibility of the aforementioned thermosetting resin composition (A), the aforementioned inorganic particles (B), and the aforementioned other functional resin composition (C) is maintained. From the viewpoint of maintaining the water dispersibility of the aforementioned resins and particles, a polystyrene sulfonate-based polymeric antistatic agent is preferred.

[0108] The aforementioned polystyrene sulfonic acid-based polymeric antistatic agent is preferably a sulfonate, for example, an alkali metal salt of sulfonate. Examples include ammonium ions (quaternary ammonium ions) or metal ions such as lithium, sodium, potassium, and calcium. From the viewpoint that the antistatic properties can be maintained even after the heating / drying process of the coating, the aforementioned metal ions are preferred.

[0109] The aforementioned antistatic agent preferably contains 4% by mass or more of the total solid components of the coating layer composition within 100% by mass. More preferably, it contains 5% by mass or more. If it is 4% by mass or more, the desired antistatic properties can be achieved. If it is 5% by mass or more, the desired antistatic properties can be achieved more stably.

[0110] Preferably, the antistatic agent comprises 20% by mass or less, for example, 15% by mass or less, of the total solid components of the coating layer. This allows for the adhesion between the coating layer and the ink, and between the coating layer and the substrate layer, without hindering the adhesion of other resins.

[0111] (Additive D) The additive (D) used in this invention, by being added to the coating layer forming composition, accomplishes the task of suppressing the formation of convex defects originating from particle aggregates on the surface after the coating layer is formed, for example, achieving improved appearance clarity during printing.

[0112] While not to be limited to a specific theory, in this invention, particularly because inorganic particles (B) and additives (D) are included together in the coating layer forming composition, protruding foreign matter of the particles can be suppressed, and a good coating film can be formed even if there is a time difference between the preparation of the coating layer forming composition and the coating. As a result, the appearance clarity of the coating layer surface can be maintained.

[0113] In this specification, the "time difference between the preparation of the coating layer forming composition and the coating" is generally within one week, for example, within three days or within 24 hours. The inventors have discovered that in the composition comprising components (A) to (C) of this invention, by further including additive (D), and more preferably additive (D) including an antifoaming agent as additive D1, the generation of convex defects originating from particle aggregates can be effectively suppressed.

[0114] In the past, the technique sought to improve the printability of inks by creating a certain degree of surface roughness on the surface layer to be printed. However, in recent years, there has been a trend to use materials with reduced environmental impact in printing inks, toners, and ink ribbons, resulting in changes in their viscosity and drying properties.

[0115] Therefore, they are also seeking technologies that improve printability using mechanisms different from those of the past.

[0116] Therefore, the inventors attempted to improve the printability of printing inks by deriving a coating layer (printing layer) with higher smoothness, and thus completed the present invention. They discovered that the improvement in smoothness is particularly due to the inclusion of inorganic particles (B) and additives (D) together in the coating layer forming composition, which suppresses the protrusions of the particles, enabling the formation of a good coating film even with a time difference between the preparation of the coating layer forming composition and the coating process.

[0117] Additives (D) can be selected within the range that do not hinder the effects achieved by the thermosetting resin composition (A) and the functional resin composition (C), and examples include defoamers, inorganic particle dispersants, and leveling agents. Furthermore, these additives can also be used in combination.

[0118] The occurrence of convex defects originating from particle agglomerates is quite diverse. For example, particle agglomerates can form during the mixing of resin and particles when forming a coating composition. Additionally, particle agglomerates can form during drying after the coating composition has been applied to a substrate. Furthermore, many particle agglomerates are known to form in this invention, particularly due to foaming during stirring when forming the coating composition or during processing and subsequent drying at the air interface without the foaming disappearing. To suppress these particle agglomerates formed during air interface drying due to foaming, it is preferable to add an antifoaming agent.

[0119] In addition, to suppress particle agglomerates formed between mixed resins and particles, it is preferable to add an inorganic particle dispersant, and to suppress particle agglomerates formed during coating drying, it is preferable to use a leveling agent.

[0120] (Additive D1: Defoamer) In this invention, defoamers used for the coating layer forming composition include mineral oil-based defoamers, silicone-based defoamers, and surfactant-based defoamers. These defoamers can also be used in combination. To improve the defoaming effect near the gas-liquid interface, mineral oil-based defoamers or silicone-based defoamers are preferred. Since the coating layer forming composition is aqueous, mineral oil-based defoamers are more preferably used to suppress the occurrence of missed coating or to prevent poor adhesion of the surface coating ink.

[0121] The content of the aforementioned defoamer in the total solid components of the coating layer is preferably 0.01% by mass or more and 1.00% by mass or less. More preferably, it is 0.05% by mass or more and 0.85% by mass or less. Even more preferably, it is 0.10% by mass or more and 0.75% by mass or less. If it is 0.01% by mass or more, it will exert a defoaming effect, and the generated bubbles will disappear, which can suppress the formation of particle agglomerates and result in good print clarity, so it is preferred. If it is 1.00% by mass or less, it can suppress the formation of coating pinholes (hajiki) caused by the defoamer and poor adhesion of the surface-coated ink, so it is preferred.

[0122] (Additive D2: Inorganic particle dispersant) In this invention, the inorganic particle dispersant used to form the coating layer composition is not particularly limited. Commonly used dispersants include anionic surfactants, cationic surfactants, nonionic surfactants, and polymeric dispersants. It can also be added from the viewpoint of suppressing particle aggregation during formulation.

[0123] The content of additive D in the total solid components of the coating layer is preferably 0.01% by mass or more and 1.20% by mass or less. For example, 0.05% by mass or more and 1.00% by mass or less, more preferably 0.05% by mass or more and 0.85% by mass or less. Further preferably 0.10% by mass or more and 0.75% by mass or less. If it is 0.01% by mass or more, it will exert the effects of defoamer and inorganic particle dispersant, which can suppress the formation of particle agglomerates and improve printing clarity, so it is preferred. If it is 1.00% by mass or less, it can suppress the formation of coating pinholes and poor adhesion of surface-coated ink, so it is preferred. In the case where multiple additives (D) are included in the present invention, the mixture can be prepared in such a way that the total amount of these components is within the above-mentioned range. For example, if an defoamer is included as additive D1 and an inorganic particle dispersant is included as additive D2, it is ideal that the amount of defoamer as additive D1 is more than the amount of inorganic particle dispersant as additive D2. By leveraging the relationship between defoamers and inorganic particle dispersants, protruding foreign matter in the particles can be suppressed, and a good coating film can be formed even if there is a time difference between the preparation of the composition and the coating.

[0124] The prepared coating, comprising a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and additives (D), can be applied to a substrate film using the aforementioned coating method and is not particularly limited. For example, it can be either an online coating method or an offline coating method.

[0125] The drying / curing temperature after coating is preferably 100°C or higher and below 200°C. A temperature above 100°C prevents insufficient drying / curing and also prevents adhesion caused by insufficient curing of the thermosetting resin composition (A), therefore, a temperature above 100°C is preferred. Furthermore, a temperature below 200°C prevents the substrate film from shrinking or deforming due to heat, allowing drying while maintaining planarity, therefore, a temperature below 200°C is preferred. The drying / curing time is preferably 1 second or higher and below 180 seconds. A time of 1 second or higher prevents insufficient drying and also prevents adhesion caused by insufficient curing of the thermosetting resin composition (A), therefore, a time of 1 second or higher is preferred. From a productivity perspective, a time below 180 seconds helps control costs, therefore, a time below 180 seconds is preferred.

[0126] The thickness of the surface coating after drying / hardening is preferably 2 to 20 μm. A thickness of 2 μm or more ensures sufficient absorption of ink after stamping, so a thickness of 2 μm or more is preferred. A thickness of 20 μm or less maintains the strength of the surface coating and prevents powder shedding, so a thickness of 20 μm or less is preferred.

[0127] In one state sample, the surface resistivity (logΩ / □) of the coating layer of the white laminated polyester film at 23°C and 65%RH is 14 or less, for example, 13.5 or less, or 13 or less.

[0128] Within this range, in addition to preventing the overlapping and transfer of the film during printing, it is also possible to prevent toner from scattering during printing.

[0129] Furthermore, the surface resistivity (logΩ / □) can be 7 or higher, for example, 7.5 or higher, or 8 or higher.

[0130] Even if the surface resistivity is low, there is no particular problem. However, by keeping the film within this range, it is possible to effectively prevent the overlapping and transfer of the film and the scattering of toner, and to suppress the amount of antistatic agent, which will reduce production costs.

[0131] The surface resistivity of the coating layer of a white laminated polyester film can be determined using known methods.

[0132] To maintain the adhesion of printing inks, the penetration of stamping inks, and the clarity of the printed matter, the surface of the white laminated polyester film with the coating layer ideally needs to maintain an appropriate roughness. For example, P1 (mmH2O) is defined as the smoothness measured at the time of coating layer formation, one hour after the coating layer composition is prepared. A smoothness P1 (mmH2O) of 50 mmH2O or more and 150 mmH2O is preferred. More preferably, it is 60 mmH2O or more and 140 mmH2O, and even more preferably, it is 70 mmH2O or more and 130 mmH2O. A smoothness of 50 mmH2O or more is preferred because it does not compromise the clarity of the printed matter. Furthermore, a smoothness of 150 mmH2O or less is preferred because it improves the adhesion of printing inks and the penetration of stamping inks. The smoothness value of this Wang Yan formula can be adjusted by combining various conditions related to this invention, such as the particle size of inorganic particles B, the ratio of B1 to B2, the amount of additive D, or the composition of additive D.

[0133] In this invention, P1(mmH2O) can be represented as: 50≦P1≦150 (Equation 1).

[0134] For example, P6 (mmH2O) is defined as the measured value of the smoothness of the coating layer at the time of formation, 6 hours after the composition of the coating layer is made. The smoothness P6 (mmH2O) is preferably 50 mmH2O or more and 150 mmH2O or less. More preferably, it is 60 mmH2O or more and 140 mmH2O or less, and even more preferably, it is 70 mmH2O or more and 130 mmH2O or less. If it is 50 mmH2O or more, it is preferable because it does not impair the clarity of the printed material. Furthermore, if it is 150 mmH2O or less, the adhesion of the printing ink and the penetration of the stamping ink are improved, which is also preferable. This smoothness value can be adjusted by combining various conditions related to this invention, such as the particle size of inorganic particles B, the ratio of B1 to B2, the amount of additive D, or the composition of additive D.

[0135] In this invention, P6 (mmH2O) can be represented as: 50≦P6≦150 (Equation 2).

[0136] Furthermore, the present invention can suppress protruding foreign matter in particles, and can form a good coating film even if there is a time difference between the preparation of the composition and the coating.

[0137] The coating layer forming composition of the present invention is envisioned to be a composition that can be processed for a long time, maintaining the clarity of the printed matter even after processing for 6 hours. One reason why prolonged processing can impair the clarity of the printed matter is the convex defects of particle agglomerates. The occurrence of convex defects can be expressed as (the measured value of Wang Yan's smoothness when forming the coating layer 1 hour after the coating layer forming composition is made) / (the measured value of Wang Yan's smoothness when forming the coating layer 6 hours after the coating layer forming composition is made).

[0138] For example, if the value of (the measured smoothness of the coating layer at the time of coating layer formation 1 hour after the coating layer is formed) / (the measured smoothness of the coating layer at the time of coating layer formation 6 hours after the coating layer is formed), i.e., (P1 / P6), shows a value greater than 1.0, it indicates that the smoothness of the coating layer at the time of coating layer formation 6 hours after the coating layer is formed is coarser than that at the time of coating layer formation 1 hour after the coating layer is formed, indicating that the convex defect system has increased.

[0139] In this invention, the value of (the measured smoothness of the coating layer at the time of forming the coating layer 1 hour after the formation of the coating layer composition) / (the measured smoothness of the coating layer at the time of forming the coating layer 6 hours after the formation of the coating layer composition), i.e., (P1 / P6), is preferably 1.8 or less. More preferably, it is 1.5 or less, and even more preferably, it is 1.2 or less. If it is 1.8 or less, as mentioned above, since fewer convex defects are generated, the appearance clarity of the printed matter is maintained, which is preferable. The lower limit value of (P1 / P6) may also be 0, but for example, it may be 0.1 or more, or 0.2 or more.

[0140] Furthermore, in this invention, the relationship (P1 / P6) can be expressed as: P1 / P6≦1.8 (Equation 3).

[0141] Hereinafter, the present invention is a white laminated polyester film, the surface smoothness of which, according to the Wang Yan-style smoothness meter, satisfies Equations 1, 2, and 3.

[0142] 50≦P1≦150 (Equation 1) 50≦P6≦150 (Equation 2) P1 / P6≦1.8 (Equation 3) With these features, the present invention can suppress protruding foreign matter of particles while maintaining the ink permeability and adhesion to UV inks, stamp inks, writing inks, etc., and can form a good coating film even when there is a time difference between the preparation of the composition of the coating layer and the coating.

[0143] The white laminated polyester film of this invention can be used for applications such as: insurance cards, qualification certificates, licenses, student IDs, medical cards, business cards and other card types, business labels and other label applications, shipping documents, printer paper, labels, etc.

[0144] Furthermore, the inks that can be applied to white laminated polyester films are not particularly limited, and can include, for example, UV-curable inks, oil-based inks, water-based inks, pencil inks, etc. [Example]

[0145] Secondly, the present invention will be described in detail using examples and comparative examples, but the present invention is not limited to the following examples. First, the evaluation method used in the present invention will be described below.

[0146] (1) Wang Yan's smoothness Using a No. 2040-C Oken-type Smoothness and Air Permeability Tester manufactured by Kumagai Riki Industrial Co., Ltd., according to JIS-P8155-2010, the Oken-type smoothness (mmH2O) of the coating layer side of a white laminated polyester film was measured.

[0147] (2) Adhesion to the coating On the coated layer of a white laminated polyester film, a 24mm wide and 50mm long celluloid adhesive tape (CT405AP-24) made by NICHIBAN was cut and applied completely to the ink layer surface using a handy rubber roller, ensuring no air gets trapped. The celluloid adhesive tape was then peeled off vertically, and the area of ​​residual coating layer within the 24mm × 50mm region was observed and judged according to the following criteria.

[0148] ◎: The remaining area of ​​the coating layer is over 99% of the total area. ○: The remaining area of ​​the coating layer is more than 90% but less than 99% of the total area. △: The remaining area of ​​the coating layer is more than 70% but less than 90% of the total area. ×: The remaining area of ​​the coating layer is less than 70% of the total area. (3) Printability of UV inks UV ink [T&K TOKA (stock), trade name "BEST CURE UV161 Blue S"] was applied to the coating layer of a white laminated polyester film and printed using a central impression printing press. After metering the ink using an anilox roller with an aperture volume of 11 cm³ / m², the ink was transferred to the entire film and then to the film. The ink transferred to the film was cured using a 160 W / cm metal halide UV lamp. The time from ink transfer to UV light irradiation was 0.94 seconds. The ink surface of the printed test pieces was observed using a HIROX RH-2000 digital microscope at 50x magnification under side illumination. The visual observation results under the digital microscope and the appearance of the printed surface were visually evaluated, and the clarity of the appearance was judged according to the following criteria.

[0149] ◎: The number of missing areas on the surface is less than 5, and the printing system is clear.

[0150] ○: There are 5 or more but less than 10 missed areas on the observation surface, but they cannot be visually identified.

[0151] △: There are more than 10 but less than 20 missed areas on the observation surface, but they cannot be visually identified.

[0152] Or, within an area of ​​A4, one or more missed coatings originating from additive D can be visually identified.

[0153] ×: If there are more than 20 instances of missed coating on the observation surface, the missed coating can also be visually identified on the surface.

[0154] (2) Adhesion to UV ink On a white laminated polyester film coating layer, UV ink [T&K TOKA (stock), trade name "BEST CURE UV161 Blue S"] was used for printing on a central roller printing press. After metering the ink using an anilox roller with an aperture volume of 11 cm³ / m², full-page transfer was performed, followed by film transfer. The ink transferred to the film was cured with a 160 W / cm metal halide UV lamp. The time from ink transfer to UV light irradiation was 0.94 seconds. Then, using NICHIBAN celluloid adhesive tape (CT405AP-24), a 24 mm wide and 50 mm long section was cut and applied completely to the ink layer surface by hand with a rubber roller, ensuring no air contamination. The celluloid adhesive tape was then peeled off vertically, and the area of ​​residual printed layer in the 24 mm × 50 mm region was observed and judged according to the following criteria.

[0155] ◎: The remaining area of ​​the printed layer is over 99% of the total area. ○: The remaining area of ​​the printed layer is more than 90% but less than 99% of the total area. △: The remaining area of ​​the printed layer is more than 70% but less than 90% of the total area. ×: The remaining area of ​​the printed layer is less than 70% of the total area. (3) Imprintability of the coating layer On a coated layer of white laminated polyester film, use Shachihata Xstanper Name 9 (pigment-based ink: XLR-9N) to stamp the text and let it stand for 1 minute. Then, gently rub the stamped area with Kimwipes and observe the degree of scratches on the text, judging it according to the following criteria.

[0156] ○: No scratches occurred at all △: Scratches have appeared, but the text is still legible. × : Difficult to read text (4) The writeability of the coating layer Write on the coated layer of white laminated polyester film using a Jetstream SXN-150-07 ballpoint pen (refill: SXR-7) and let it rest for 1 minute. Then, gently rub the writing area with Kimwipes, observe the degree of smudges, and judge according to the following criteria.

[0157] ○: No scratches occurred at all △: Scratches have appeared, but the text is still legible. × : Difficult to read text (5) Printability of LBP toner Using an ApeosPort-V C3376 from FUJI XEROX Corporation, arbitrary patterns were printed on the coating layer of a white laminated polyester film. The toner surface of the printed test pieces was observed using a HIROX RH-2000 digital microscope at 50x magnification under side illumination. The visual observations under the digital microscope and the appearance of the printed surface were compared, and the clarity of the appearance was judged according to the following criteria.

[0158] ◎: No missing areas on the printing surface; the printing system is clear.

[0159] ○: Less than 10 areas of missed coating occur on the observation surface, but they are not visually identifiable.

[0160] △: There are more than 10 but less than 20 missed areas on the observation surface, but they cannot be visually identified.

[0161] Or, within an area of ​​A4, one or more missed coatings originating from additive D can be visually identified.

[0162] ×: More than 20 instances of missed coating occur on the observed surface, and the missed coating can also be visually identified on the surface.

[0163] (6) LBP toner setting properties Using a FUJI XEROX ApeosPort-V C3376 printer, an arbitrary pattern was printed onto the coated layer of a white laminated polyester film. Then, using NICHIBAN celluloid adhesive tape (CT405AP-24), a 24mm wide and 50mm long section was cut and applied completely to the ink layer surface using a hand-held rubber roller, ensuring no air contamination. The celluloid adhesive tape was then peeled off vertically, and the area of ​​residual printed layer within the 24mm x 50mm region was observed and judged according to the following criteria.

[0164] ○: The residual toner on the surface coating of the film is more than 90% of the area. △: The residual toner on the surface coating of the film is above 70% and below 90% of the area. ×: The residual toner on the surface coating of the film is less than 70% of the area. (5) Printability of heat transfer ink belt Using a heat transfer ink ribbon (Ricoh B-110C resin type black) mounted on a Bon Denki BLP-323, arbitrary barcode patterns were printed on the coated layer of a white laminated polyester film. The barcode patterns on the printed test pieces were observed using a HIROX RH-2000 digital microscope at 50x magnification under side illumination. The visual observations under the digital microscope and the appearance of the printed surface were compared, and the clarity of the appearance was judged according to the following criteria.

[0165] ◎: No missing areas on the printing surface; the printing system is clear.

[0166] ○: Less than 10 areas of missed coating occur on the observation surface, but they are not visually identifiable.

[0167] △: There are more than 10 but less than 20 missed areas on the observation surface, but they cannot be visually identified.

[0168] Or, within an A4 area, one or more missed coatings originating from additive D can be visually identified.

[0169] ×: More than 20 instances of missed coating occur on the observed surface, and the missed coating can also be visually identified on the surface.

[0170] (5) Adhesion to the heat transfer ink tape Using a heat transfer ink tape (Ricoh B-110C resin type black), mounted on a Bon Denki BLP-323, an arbitrary barcode pattern was printed on a white laminated polyester film coating. Then, using NICHIBAN celluloid adhesive tape (CT405AP-24), a 24mm wide and 50mm long section was cut and applied completely to the ink layer surface using a hand-held rubber roller, ensuring no air ingress. The celluloid adhesive tape was then peeled off vertically, and the area of ​​residual printed layer within the 24mm x 50mm region was observed and judged according to the following criteria.

[0171] ◎: The remaining area of ​​the printed layer is over 99% of the total area. ○: The remaining area of ​​the printed layer is more than 90% but less than 99% of the total area. △: The remaining area of ​​the printed layer is more than 80% but less than 90% of the total area. ×: The remaining area of ​​the printed layer is more than 70% but less than 80% of the total area. (7) Dusting property The dust shedding property was evaluated using a dust shedding vibration friction tester (manufactured by Yamaguchi Scientific Industries Co., Ltd.). Black backing paper (manufactured by GA board-FS, Y-me, and Takeo Co., Ltd.) was used at the contact area between the load head and the film. The load on the head was set to 200gf / 25mm2 (5mm×5mm) [0.0785MPa]. The condition of the black backing paper after the film was rubbed against the load head for 3 round trips was visually evaluated using 5 limit samples. A result of 3 or higher was considered acceptable.

[0172] (8) Surface resistivity of the coating layer After placing the white laminated polyester film in a gas environment of 23°C and 65%RH for 24 hours, the surface resistivity (logΩ / □) of the coating layer was measured using a surface resistivity measuring device (Mitsubishi Yuka Co., Ltd., Hiresta-IP) under the same gas environment with an applied voltage of 500V for 10 seconds.

[0173] (9) Mirror gloss of the coating layer surface of white laminated polyester film The measurements were performed according to Method 3 (60-degree specular gloss) as described in JIS-Z8741.

[0174] (10) Surface roughness (Ra), maximum protrusion height (Rz) Ra and Rz were measured using the formulas according to ISO 4287:1997, specifically the arithmetic mean roughness and the maximum protrusion height. A VK-X100 laser microscope (manufactured by Keyence) was used for the measurements. Four random points were measured within a 250μm × 250μm square, and the average value was taken as the surface roughness or maximum protrusion height (unit: μm).

[0175] [Thermosetting Resin Composition (A)] (Polymerization of urethane resin A-1 with a polycarbonate structure) In a four-necked flask equipped with a stirrer, a Deutsche condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 25 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 5 parts by mass of dimethylolpropionic acid, 52 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2600, 6 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution reached the specified amine equivalent. Next, 18 parts by mass of a polyisocyanate compound with a triisocyanate structure (manufactured by Asahi Kasei Chemicals, Durnate TPA, 3-functional) using hexamethylene diisocyanate as a raw material was added, and the mixture was stirred at 75°C for 1 hour under a nitrogen atmosphere to confirm that the reaction solution reached the specified amine equivalent. Subsequently, the temperature of the reaction solution was lowered to 50°C, and 8 parts by mass of methyl ethyl ketone oxime were added dropwise. After cooling the reaction solution to 40°C, 5.17 parts by mass of triethylamine were added to obtain a polyurethane prepolymer solution. Next, in a reaction vessel equipped with a high-speed homogenizer, 450 g of water was added and the temperature adjusted to 25°C. The polyurethane prepolymer solution was then added while stirring for 2000 min⁻¹ to achieve water dispersion. Subsequently, under reduced pressure, a 35% by mass water-dispersible polyurethane resin solution (A-1) was prepared by removing acetone and a portion of the water.

[0176] • Melamine resin A-2 (Amidia (registered trademark) M-3, manufactured by DIC, solid content 80% by weight) • Carbodiimide resin A-3 (Carbodilite (registered trademark) V-10, manufactured by Nisshin Spinning Co., Ltd., solid content 40% by weight), ·Including Azoline-based resin A-4 (Epocros (registered trademark) WS-300, manufactured by Nippon Shokubai Co., Ltd., solid content 10% by mass) [Inorganic particles B1]: • Calcium carbonate B-1 (HAKUENKA (registered trademark) Pz, manufactured by Shiraishi Calcium Co., Ltd., 100% by weight of solids, average particle size 0.2 μm) • Calcium carbonate B-2 (Brilliant (registered trademark)-15, manufactured by Shiraishi Calcium, average particle size 0.15 μm, solids content 100% by mass) • Calcium carbonate B-3 (Tunex (registered trademark) E, manufactured by Shiraishi Calcium, average particle size 0.5 μm, solids content 100% by mass) [Inorganic particles B2]: Silicon dioxide B-4 (Sylysia 440, manufactured by Fuji Silysia Chemical Co., Ltd., average particle size 6.2 μm, solids content 100% by mass) • Silicon dioxide B-5 (Sylysia 450 (registered trademark), manufactured by Fuji Silysia Chemical Co., Ltd., average particle size 8.0 μm, solids content 100% by mass) [Functional Resin Composition (C)]: • Styrene-acrylic resin C-1 (Saibinooru (registered trademark) EK215, manufactured by SAIDEN CHEMICAL, solid content 25% by mass) • Polyester resin C-2 (Vylonal (registered trademark) MD1200, manufactured by Toyobo Co., Ltd., solid content 34% by mass) • High molecular weight antistatic agent C-3 (EL polymer WS-52R, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content 10% by mass) • High molecular weight antistatic agent C-4 (Fujistat YE910, manufactured by Fujichemical, 15% by mass solid content) • High molecular weight antistatic agent C-5 (Fujistat YE125, manufactured by Fujichemical Corporation, solid content 25% by mass) [Additive D1] • Mineral oil-based defoamer D-1 (Olfine AF-300, manufactured by Nissin Chemical Industry Co., Ltd., 90% solids by mass) • Mineral oil-based defoamer D-2 (SN Deformer 777, manufactured by SAN NOPCO, 96% solids by mass) Silicone-based defoamer D-3 (BYK-024, manufactured by BYK Corporation, 96% solids by mass) [Additive D2] Inorganic particle dispersant D-4 (ALON T-50, manufactured by Dong-A Synthetic Co., Ltd., solid content 40% by mass) Inorganic particle dispersant D-5 (Poise 521, manufactured by Kao Corporation, solid content 40% by mass) (Substrate film) •Crisper (registered trademark) K1211: White polyester film with voids, manufactured by Toyobo Co., Ltd., single-sided corona treatment / single-sided untreated, apparent density 1.1 g / cm3, Ra=0.1μm, Rz=3μm, S=2μm (Ra, Rz, S are data of the corona-treated surface) •Crisper (registered trademark) K2323: A white polyester film with voids, manufactured by Toyobo Co., Ltd., easy to bond on both sides, apparent density 1.1 g / cm3, Ra=0.3μm, Rz=7μm, S=2μm (Ra, Rz, and S are essentially the same on both surfaces). (Example 1) (Preparation of coating layer forming composition 1) Coating layer forming composition 1 with the following composition was prepared. Since the coating layer forming composition was used 1 hour after preparation and 6 hours after preparation, it was divided into 2 parts after preparation. From the preparation of the coating layer forming composition to its use, a dissolver (type: CA30, manufactured by Yinghong Precision Machinery Co., Ltd.) was used for stirring at a rotation speed of 200 rpm.

[0177] (Coating layer composition 1) 44.15 parts by weight of water 2.29 parts by weight of urethane resin A-1 3.67 parts by weight of melamine resin A-2 Calcium carbonate B-1 3.08 parts by weight Calcium carbonate B-2 6.15 parts by weight Calcium carbonate B-4 4.43 parts by weight Styrene-acrylic resin C-1 5.60 parts by weight Polyester resin C-2 15.81 parts by weight Polymer-type antistatic agent C-3 14.75 parts by weight Mineral oil-based defoamer D-1 0.09 parts by weight (Coating and drying of the substrate film) Using a 50 μm thick polyester synthetic paper Crisper K1211 as the substrate film, a coating layer composition 1 was formed on the corona-treated surface of K1211 by using a reverse gravure to achieve a coating layer thickness of 10 μm after drying. The coating was dried at 180°C for 20 seconds. The white laminated polyester film described in Example 1 was coated one hour after the coating layer composition was formed and six hours after the coating layer composition was formed to form a coating layer.

[0178] (Examples 2-22, Comparative Example 1) Examples 2-22 and Comparative Example 1 were coated and dried / cured in the same manner as in Example 1, except that the substrate film, coating composition, coating surface and thickness after drying were changed as shown in Tables 1 and 2, to obtain white laminated polyester films.

[0179] In Tables 1 and 2, the composition ratios of the thermosetting resin component A, inorganic particles B, functional resin component C, and additive D in the coating layer forming composition are expressed as the mass parts of each solid component when the overall solid content ratio is set to 100. The actual coating layer forming composition is formulated by adding water to achieve an overall solid content ratio of 25%.

[0180] The following table presents the blending amount and various physical properties of each component.

[0181] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Coating layer formation Composition (composition) The ratio is based on the proportions of each solid component. (in units of mass) Composition number 1 2 3 4 5 6 7 8 5 9 10 11 12 thermosetting resin composition A Carbamate A-1 3.2 7.9 7.9 7.9 7.9 7.9 7.9 7.9 7.9 5.2 7.9 7.9 7.9 melamine A-2 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 Carbodiimide A-3 8.8 zoline A-4 8.8 Inorganic particles B1 Small particles B-1 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 12.3 B-2 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 24.6 B-3 Inorganic particles B2 large particles B-4 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 B-5 17.7 Functional resins Composition C Styrene Acrylic C-1 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 Polyester C-2 21.5 16.8 16.8 17.1 16.6 16.8 17.1 16.2 16.6 19.3 16.6 16.6 25.4 polymeric Antistatic agent C-3 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 C-4 C-5 Additive D1 Mineral oil-based defoamers D-1 0.35 0.35 0.35 0.35 0.05 0.8 0.35 0.35 0.35 0.35 0.35 D-2 0.35 Silicone-based defoamers D-3 0.1 Additive D2 Inorganic particle dispersants D-4 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 D-5 0.2 0.2 0.2 0.2 0.2 0.2 0.2 total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Original film K1211 K1211 K1211 K1211 K1211 K1211 K1211 K1211 K2323 K1211 K1211 K1211 K1211 Coated surface Corona face Corona face Corona face Corona face Corona face Corona face Corona face Corona face Easy to connect face Corona face Corona face Corona face Corona face Coating thickness (μm) 10 10 10 10 10 10 10 10.0 10.0 10.0 10.0 10.0 10.0 Thermosetting resin (A) content (mass %) 12.0 16.7 16.7 16.7 16.7 16.7 16.7 16.7 16.7 14.0 16.7 16.7 7.9 Inorganic particle (B) content (mass%) 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 Functional resin (C) content (mass %) 33.0 28.3 28.3 28.6 28.1 28.3 28.6 27.7 28.1 30.8 28.1 28.1 36.9 Additive (D) content (mass %) 0.4 0.4 0.4 0.1 0.6 0.4 0.1 1.0 0.6 0.6 0.6 0.6 0.6 Carbamate polycarbonate structure have have have have have have have have have have have have have Branching structure have have have have have have have have have have have have have B1 / B2 ratio (%) 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08 2.08

[0182] [Table 2] Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 Example 21 Example 22 Comparative Example 1 Coating layer composition (The composition ratio is expressed as the mass parts of each solid component.) Composition number 13 14 15 16 17 18 19 20 twenty one twenty two thermosetting resins Composition A Carbamate A-1 7.9 7.9 7.9 7.9 7.9 7.9 7.9 3.2 3.2 3.2 melamine A-2 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 Carbodiimide A-3 zoline A-4 Inorganic particles B1 Small particles B-1 12.3 12.3 19.1 5.5 10.2 14.7 12.3 12.3 12.3 B-2 24.6 24.6 24.6 27.4 10.7 21.3 29.5 24.6 24.6 24.6 B-3 12.3 Inorganic particles B2 large particles B-4 17.7 17.7 17.7 8.1 38.4 14.1 21.3 17.7 17.7 17.7 B-5 Functional resins Composition C Styrene Acrylic C-1 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 Polyester C-2 25.4 16.6 16.6 16.6 16.6 25.6 5.7 20.2 21.5 21.9 Antistatic agent C-3 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 C-4 5.9 C-5 5.9 Additive D1 Mineral oil-based defoamers D-1 0.35 0.35 0.35 0.35 0.35 0.35 0.35 1.5 D-2 Silicone-based defoamers D-3 0.2 Additive D2 Inorganic particle dispersants D-4 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 D-5 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Original film K1211 K1211 K1211 K1211 K1211 K1211 K1211 K1211 K1211 K1211 Coated surface Corona face Corona face Corona face Corona face Corona face Corona face Corona face Corona face Corona face Corona face Coating thickness (μm) 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10 10 10 Thermosetting resin (A) content (mass %) 7.9 16.7 16.7 16.7 16.7 16.7 16.7 12.0 12.0 12.0 Inorganic particle (B) content (mass%) 54.6 54.6 54.6 54.6 54.6 45.6 65.5 54.6 54.6 54.6 Functional resin (C) content (mass %) 36.9 28.1 28.1 28.1 28.1 37.1 17.2 31.7 33.0 33.4 Additive (D) content (mass %) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 1.7 0.4 0.0 Carbamate polycarbonate structure have have have have have have have have have have Branching structure have have have have have have have have have have B1 / B2 ratio (%) 2.08 2.08 2.08 5.74 0.42 2.23 2.08 2.08 2.08 2.08

[0183] The evaluation results of each embodiment and comparative example are presented in Tables 3 and 4. The white laminated polyester film taken 1 hour after the start of coating was used only for the Wang Yanshi smoothness test, while the white laminated polyester film taken 6 hours after the start of coating was used for other evaluations.

[0184] [Table 3] Example 1 2 3 4 5 6 7 8 9 10 11 12 13 Wang Yan's smoothness P1 (mmH2O) 80 85 82 74 101 90 90 120 90 97 92 89 65 Wang Yan's smoothness P6 (mmH2O) 60 62 66 50 100 86 62 110 88 99 99 83 50 P1 / P6 1.3 1.4 1.2 1.5 1.0 1.0 1.5 1.1 1.0 1.0 0.9 1.1 1.3 Coating close contact ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ UV ink printability ○ ○ ○ △ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ○ UV ink sealing ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ Stamping ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Writing characteristics ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Toner printability ○ ○ ○ △ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ○ Toner setting properties ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Thermal stamp printing performance ○ ○ ○ △ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ○ Heat-transfer ink band closeness ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ Dust-shedding property 5 5 5 4 5 5 5 5 5 5 5 5 5 AS property (LogΩ / □) 11.6 11.0 12.5 11.6 11.0 11.9 11.0 9.8 11.6 11.6 11.9 11.5 11.8 60-degree specular gloss (%) 1.8 1.8 1.9 1.9 1.8 1.8 2.0 1.8 1.9 1.9 2.1 1.7 1.9 85-degree specular gloss (%) 3.4 3.4 3.5 3.3 4.2 4.0 3.3 5.3 3.9 3.6 3.9 3.7 3.3 Surface roughness (Ra, μm) 1.1 1.1 1.2 1.1 1.1 1.2 1.2 1.2 1.2 1.2 1.1 1.1 1.7 Maximum protrusion height (Rz, μm) 11.2 10.3 12.5 11.3 11.6 12.6 12.3 12.2 12.2 11.5 10.2 12.4 17.8

[0185] [Table 4] Example Comparative example 14 15 16 17 18 19 20 twenty one twenty two 1 Wang Yan's smoothness P1 (mmH2O) 91 100 97 140 65 122 70 101 101 64 Wang Yan's smoothness P6 (mmH2O) 62 102 94 100 50 121 68 103 103 29 P1 / P6 1.5 1.0 1.0 1.4 1.3 1.0 1.0 1.0 1.0 2.2 Coating tight ◎ ◎ ◎ ◎ ○ ◎ ◎ ○ ○ △ UV ink printability ○ ◎ ◎ △ △ ○ ○ △ △ × UV ink sealing ◎ ◎ ◎ ◎ ○ ◎ ◎ ○ ○ △ Stamping ○ ○ ○ △ △ ○ ○ ○ ○ ○ Writing characteristics ○ ○ ○ △ ○ ○ ○ ○ ○ ○ Toner printability ○ ◎ ◎ △ △ ○ ○ △ △ × Toner setting properties ○ ○ ○ ○ △ ○ ○ ○ ○ △ Heat transfer ink ribbon printability ○ ◎ ◎ △ △ ○ ○ △ △ × Thermal transfer ink ribbon adhesion ◎ ◎ ◎ ◎ ○ ◎ ◎ ○ ○ △ Powder shedding 5 5 5 5 3 5 3 5 5 2 AS property (LogΩ / □) 11.7 11.0 13.4 12.3 12.2 11.9 11.5 13.7 13.7 11.3 60-degree specular gloss (%) 2.0 2.0 2.0 1.8 2.1 2.1 1.7 1.9 1.9 1.9 85-degree specular gloss (%) 3.3 4.0 3.8 4.4 3.2 4.1 3.3 4.1 4.1 3.1 Surface roughness (Ra, μm) 1.1 1.2 1.0 0.9 1.3 1.1 1.1 1.1 1.1 1.2 Maximum protrusion height (Rz, μm) 10.9 12.3 12.2 10.1 14.2 10.2 12.4 11.0 11.0 12.1

[0186] In Examples 1 to 22, the coating is well-adhesive and has good adhesion for various printing processes. It also has both stamping and writing properties. Furthermore, due to the presence of additive D, the smoothness P1 and P6 of the Wang Yan type and the P1 / P6 index for generating protrusions meet the desired range, indicating that the clarity of the printed appearance is also good.

[0187] On the other hand, in Comparative Example 1, since additive D was not added, the smoothness P1 and P6 of Wang Yan's method, and the P1 / P6 index which is the indicator of the generation of protrusions, were outside the expected range. It can be seen that the appearance clarity after printing deteriorated and misprints occurred. Furthermore, it can be seen that the increase of protrusions caused powdering and reduced printing adhesion.

[0188] [Potential for industrial application] According to the present invention, a laminated white polyester film can be provided, which has the properties of adhesion of the coating layer to the substrate layer, adhesion to UV ink, imprintability, and writeability.

[0189] According to the present invention, a laminated white polyester film can be provided, which can improve the adhesion of the coating layer to the substrate layer, the adhesion of the coating layer to printing ink, such as UV printing ink, and has fewer protrusions due to particle aggregation even after long-term processing, can maintain excellent appearance clarity, and has stampability and writeability.

Claims

1. A white laminated polyester film having a coating layer composed of a coating layer forming composition on at least one side of a white polyester resin layer, the coating layer forming composition comprising a thermosetting resin composition (A), inorganic particles (B), a functional resin composition (C), and an additive (D), wherein the thermosetting resin composition (A) contains an aminocarbamate resin having a polycarbonate structure and a branched structure, and the aminocarbamate resin accounts for 3-12% by mass of 100% of the total solid components of the coating layer forming composition; the additive (D) is at least one selected from defoamers, inorganic particle dispersants, and leveling agents; and the smoothness of the surface of the coating layer, according to a Wang Yan smoothness meter, satisfies Equations 1, 2, and 3: 50≦P1≦150 (Equation 1) 50≦P6≦150 (Equation 2) P1 / P6≦1.8 (Equation 3) (In the formula, P1(mmH2O) represents the measured value of Wang Yan's smoothness when the coating layer is formed 1 hour after the coating layer composition is made, and P6(mmH2O) represents the measured value of Wang Yan's smoothness when the coating layer is formed 6 hours after the coating layer composition is made).

2. The white laminated polyester film of claim 1, wherein the inorganic particles (B) comprise two or more types of particles (B1) with an average particle size of 0.1 μm or more and less than 1.0 μm, and particles (B2) with an average particle size of 1.0 μm or more and less than 10.0 μm, and the blending amounts of B1 and B2 have the following relationship: B1 / B2 = 0.1 to 4.0; the content of inorganic particles (B) in the total solid components of the coating layer is 30 to 70% by mass.

3. The white laminated polyester film of claim 1, wherein the functional resin composition (C) is a compound comprising at least one selected from polyester resin, acrylic / styrene copolymer resin, and polymeric antistatic agent, and the content of functional resin (C) in the total solid components of the coating layer is 15 to 50% by mass.

4. The white laminated polyester film of claim 3, wherein the polymeric antistatic agent is a resin having at least a sulfonate.

5. The white laminated polyester film of claim 4, wherein the sulfonate is an alkali metal sulfonate.

6. The white laminated polyester film of claim 1, wherein the surface resistivity (logΩ / □) of the coated layer of the white laminated polyester film at 23°C and 65%RH is 14 or less.

7. The white laminated polyester film of claim 1, wherein the content of the additive (D) in the total solid components of the coating layer is more than 0.01% by mass and less than 1.20% by mass.

8. The white laminated polyester film of claim 1, wherein the additive (D) comprises an antifoaming agent as additive D1.

9. The white laminated polyester film of claim 1, wherein the additive (D) comprises a mineral oil-based defoamer as additive D1.