Laser color developing multilayer film, laminate for plastic card and laminate for electronic passport having the multilayer film, passport etc. having the multilayer film, and method of using the multilayer film as passport etc.

Abstract

Provided is a newly constructed laser color-developing multilayer film, wherein the contrast between the printed portion and the portion other than the printed portion is higher than before, the laser color-developing multilayer film having at least two layers, a layer (A) and a color-developing layer (B), wherein the layer (A) comprises an amorphous aromatic polyester resin and an antioxidant, wherein the content of the antioxidant is 0.05 to 4 parts by weight relative to 100 parts by weight of the amorphous aromatic polyester resin, and the color-developing layer (B) comprises a polycarbonate resin and a laser color-developing agent, wherein the laser color-developing agent is a metal oxide, and the content of the antioxidant in the color-developing layer (B) is less than 0.05 parts by weight relative to 100 parts by weight of the polycarbonate resin.

Description

Technical Field

[0001] The present invention relates to a laser color developing multilayer film, a laminate for plastic cards and an electronic passport comprising the multilayer film, a passport etc. comprising the multilayer film, and a method of using the multilayer film as a passport etc. Background Art

[0002] Credit cards, cash cards, ID cards, label cards, insurance cards, etc. are made by overlapping multiple card sheets, heating and fusing the sheets using a vacuum press, and then punching them out using a punching machine to make them into a card shape. Such cards are irradiated with lasers to mark text, barcodes, etc. For example, instead of printing barcodes, facial photos, etc., the personal number, batch number, or personal information, facial photos, etc. of the card are written on the card using YAG lasers, etc. If information is written on the card using lasers, etc., it is possible to prevent personal information from disappearing due to wear and tear or degradation over time. In addition, marking using lasers can be performed in a simple process, so the industrial value is also high and has attracted much attention.

[0003] For these laser-marked cards, the contrast between the printed portion and the portion other than the printed portion must be high so that clear characters, symbols, and images can be obtained. These characteristics are also important in preventing tampering and forgery of the card.

[0004] Patent Document 1 describes a transparent laser marking multilayer sheet having at least three layers including a skin layer and a core layer. In the transparent laser marking multilayer sheet of Patent Document 1, as described in the examples, the core layer is formed by adding a color developer (carbon black) and an antioxidant to polycarbonate.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-194757 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] An object of the present invention is to provide a laser color developing multilayer film having a new structure, which has a higher contrast between a printed portion and a portion other than the printed portion than conventional films.

[0010] Solutions for solving problems

[0011] In order to solve the above-mentioned problems, the present inventors found the following matters.

[0012] (1) The metal oxide used as the laser developer reacts with the antioxidant, so the laser developer turns black, which affects the color tone of the film.

[0013] (2) In order to prevent the above situation, the content of the antioxidant in the color-developing layer (B) (it is necessary to make the color-developing layer (Y)) below a prescribed value, and preferably zero;

[0014] (3) In order to prevent the ester exchange reaction at the interface between layer (A) and color-developing layer (B) (the interface between layer (X) and color-developing layer (Y)), an antioxidant (and / or an ester exchange inhibitor) must be added to layer (A) (layer (X)).

[0015] As a result of intensive studies on these matters, the present inventors have accomplished the following.

[0016] The present invention discloses a laser color developing multilayer film as a first embodiment, which has at least two layers of a layer (A) and a color developing layer (B).

[0017] The layer (A) comprises an amorphous aromatic polyester resin and an antioxidant, wherein the content of the antioxidant is 0.05 to 4 parts by mass based on 100 parts by mass of the amorphous aromatic polyester resin.

[0018] The color developing layer (B) comprises a polycarbonate resin and a laser color developing agent, wherein the laser color developing agent is a metal oxide, and the content of the antioxidant in the color developing layer (B) is less than 0.05 parts by mass based on 100 parts by mass of the polycarbonate resin.

[0019] In the first embodiment, the content of the laser color developer per unit area is preferably 135 μg / cm 2 above.

[0020] In the first embodiment, the content of the laser color developer per unit area is preferably 135 to 250 μg / cm 2 .

[0021] In the first aspect, it is preferred that the color development layer (B) does not contain an antioxidant.

[0022] In the first aspect, the metal oxide is preferably a bismuth-based metal oxide.

[0023] In the first aspect, the antioxidant is preferably dibutylhydroxytoluene and / or a trialkyl phosphite.

[0024] The laser color developing multilayer film of the first embodiment preferably has a total light transmittance of 84% or more.

[0025] In the first aspect, the color development layer (B) preferably has a thickness of 50 μm or more and 200 μm or less.

[0026] In the first aspect, it is preferred that a sublimation type thermal transfer image receiving layer (C) is further provided on at least one surface of the laser color developing multilayer film.

[0027] The present invention discloses a laminate for plastic cards as a second embodiment, which comprises the laser color developing multilayer film of the first embodiment.

[0028] The present invention discloses a laminate for an electronic passport as a third embodiment, which comprises the laser color developing multilayer film of the first embodiment.

[0029] The present invention discloses a laser color developing multilayer film as a fourth embodiment, which is used for passports, IC cards, magnetic cards, driver's licenses, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration cards, vehicle inspection certificates, label cards, prepaid cards, cash cards and credit cards. The laser color developing multilayer film has at least two layers of a layer (X) and a color developing layer (Y).

[0030] One of the layer (X) and the color development layer (Y) contains a polyester resin as a resin component, and the other layer contains a polycarbonate resin as a resin component,

[0031] The layer (X) contains an antioxidant and / or an ester exchange inhibitor, and the content of the antioxidant and / or the ester exchange inhibitor is 0.01 parts by mass or more based on 100 parts by mass of the resin component.

[0032] The color developing layer (Y) contains a laser color developing agent, and the laser color developing agent is a metal oxide. The content of the antioxidant in the color developing layer (Y) is less than 0.1 parts by mass based on 100 parts by mass of the resin component.

[0033] In the fourth aspect, the content of the antioxidant and / or transesterification inhibitor in the layer (X) is preferably 0.05 to 4 parts by mass based on 100 parts by mass of the resin component.

[0034] In the fourth aspect, it is preferred that the color development layer (Y) does not contain an antioxidant.

[0035] In the fourth aspect, the metal oxide is preferably an oxygen-deficient type.

[0036] In the fourth aspect, the metal oxide is preferably a bismuth-based metal oxide.

[0037] In the fourth aspect, it is preferred that the layer (X) contains a polyester resin, and the color development layer (Y) contains a polycarbonate resin.

[0038] In the fourth aspect, the polyester-based resin is preferably an amorphous polyester-based resin.

[0039] The present invention discloses a passport, IC card, magnetic card, driver's license, residence permit, qualification certificate, employee card, student card, personal number card, seal registration certificate, vehicle inspection certificate, label card, prepaid card, cash card and credit card as the fifth mode, which has the laser color-rendering multilayer film of the fourth mode.

[0040] The present invention discloses, as the sixth method, a method of using the laser color-developing multilayer film of the fourth method as a passport, IC card, magnetic card, driver's license, residence permit, qualification certificate, employee ID card, student ID card, personal number card, seal registration certificate, vehicle inspection certificate, label card, prepaid card, cash card and credit card.

[0041] In addition, the present invention discloses the application of the laser color-rendering multilayer film of the fourth mode as a passport, IC card, magnetic card, driver's license, residence permit, qualification certificate, employee ID card, student ID card, personal number card, seal registration certificate, vehicle inspection certificate, label card, prepaid card, cash card and credit card as the seventh mode.

[0042] Effects of the Invention

[0043] In the laser color developing multilayer film of the present invention, the content of the antioxidant in the color developing layer (B) (color developing layer (Y)) is limited to a specified value or less, thereby suppressing the coloring of the entire film and improving the contrast between the printed portion and the portion other than the printed portion. In addition, by adding an antioxidant (and / or an ester exchange inhibitor) to layer (A) (layer (X)), an ester exchange reaction at the interface between layer (A) and color developing layer (B) (the interface between layer (X) and color developing layer (Y)) can be prevented, foaming can be prevented, and the visual recognition of the printed portion can be well maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 (a) and (b) are schematic diagrams showing the layer structure of the laminate for plastic cards.

[0045] Figure 2 (a) and (b) are schematic diagrams showing the layer structure of the laminate for electronic passport. DETAILED DESCRIPTION

[0046] Hereinafter, a laser color developing multilayer film, a laminate for plastic card, a laminate for electronic passport, a passport, etc., and a method of using the multilayer film as a passport, etc., as an example of an embodiment of the present invention will be described. However, the protection scope of the present invention is not limited to the embodiments described below.

[0047] The present invention will be described in detail below. It should be noted that the description "a to b" indicating a numerical range means "a or more and b or less" unless otherwise specified, and includes the meanings of "preferably greater than a" and "preferably less than b".

[0048] In addition, when the upper limit and the lower limit of the numerical range in this specification are slightly outside the numerical range specified in the present invention, as long as the same effects as those in the numerical range are achieved, they are included in the equivalent range of the present invention.

[0049] It should be noted that the "coloring" in the present invention only requires that there is a clear visual difference between the uncolored part and the colored part, and does not need to have color. Therefore, the "coloring" in the present invention also includes achromatic colors such as black and gray.

[0050] <Laser color developing multilayer film of the first embodiment>

[0051] The laser color-developing multilayer film of the first embodiment comprises at least two layers of a layer (A) and a color-developing layer (B). Each layer will be described below.

[0052] (Layer(A))

[0053] The layer (A) contains an amorphous aromatic polyester-based resin and an antioxidant.

[0054] ·Amorphous aromatic polyester resin

[0055] The amorphous aromatic polyester resin may be a substantially amorphous polyester resin. As substantially amorphous (including low-crystalline) polyester resins, there can be used: polyester resins that do not show a clear crystal melting peak when heated by differential scanning calorimetry (DSC); polyester resins that have crystallinity but a slow crystallization rate and do not become highly crystalline when a film is made by an extrusion film-making method; and polyester resins that have crystallinity but a crystal melting heat (ΔHm) as low as 10 J / g or less when heated by differential scanning calorimetry (DSC). That is, the amorphous aromatic polyester resin in the present invention also includes "crystalline aromatic polyester resins in an amorphous state".

[0056] As the resin component used in layer (A), the above-mentioned amorphous aromatic polyester resin is preferably used as the main component. Here, "main component" means that the total mass of the resin component of layer (A) is taken as the reference (100 mass%), and contains 55 mass% or more, preferably 70 mass% or more, more preferably 90 mass% or more, and further preferably 95 mass% or more. The upper limit is 100 mass%.

[0057] The substantially non-crystalline aromatic polyester resin of layer (A) is preferably a copolyester containing terephthalic acid as the main dicarboxylic acid component and 20 mol% to 80 mol% of 1,4-cyclohexanedimethanol (1,4-CHDM) and 20 mol% to 80 mol% of ethylene glycol as the main diol component, from the perspective of easy availability of raw materials. It should be noted that terephthalic acid as the main dicarboxylic acid component as the raw material for producing polyester may be dimethylterephthalic acid.

[0058] Here, the "main component" in the dicarboxylic acid component means that terephthalic acid is contained in an amount of 70 mol% or more, preferably 80 mol% or more, and more preferably 98 mol% or more, based on the entire amount of the dicarboxylic acid component (100 mol%). In addition, the "main component" in the diol component means that 1,4-CHDM and ethylene glycol are contained in an amount of preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, based on the entire amount of the diol component (100 mol%).

[0059] When the amount of 1,4-CHDM in the diol component is greater than the lower limit, the characteristics of the crystalline resin are suppressed and the adhesiveness becomes good. On the contrary, when the amount of 1,4-CHDM is less than the upper limit, the crystallinity is still suppressed, which is preferred.

[0060] In the copolyester resin within this composition range, in the composition in which 1,4-CHDM is about 30 mol% of the diol component, no crystallization behavior is confirmed in the DSC (differential scanning calorimeter) measurement, and it is known to show complete amorphousness. As the completely amorphous polyester resin, PETG resin can be cited. As PETG resin, for example, "Eastar GN001" manufactured by Eastman Chemical Company can be cited. PETG resin is used for many purposes, and from the perspective of establishing a stable supply system of raw materials, it is particularly preferred as a resin component that becomes the main body of layer (A) of the present invention.

[0061] However, the present invention is not limited thereto, and Eastman Chemical Company's "PCTG·5445" (a copolymerized polyester resin in which the dicarboxylic acid component is terephthalic acid, about 60 mol% of the diol component is 1,4-CHDM, and about 40 mol% is ethylene glycol) which shows crystallinity under specific conditions but can be handled as an amorphous resin under normal extrusion film-making conditions may also be used. In addition, neopentyl glycol copolymerized PET resins which do not show crystallinity (for example, "Cosmostar·SI-173" manufactured by Toyobo Co., Ltd.); low crystallinity PET resins such as PET resins obtained by copolymerizing diethylene glycol, PET resins obtained by copolymerizing isophthalic acid, PBT resins with low crystallinity, etc., which have a structure that hinders crystallization by introducing various copolymerization components, may also be used as substantially amorphous polyester resins that form the main body of layer (A). Furthermore, among the polyester resins exemplified above, polyester resins obtained by replacing part or all of terephthalic acid with naphthalene dicarboxylic acid are also amorphous and can be used in the same manner.

[0062] Antioxidants

[0063] As the antioxidant, for example, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. can be used. Among them, phenolic antioxidants and phosphorus antioxidants are preferred. The antioxidant can be used by mixing two or more. By using two or more antioxidants, the molecular weight reduction and yellowing of the resin during extrusion film making can be effectively suppressed. In addition, by using two or more antioxidants, the stability during extrusion film making and the long-term stability as a molded product (film, laminate) can also be taken into account.

[0064] Examples of the phenolic antioxidant include α-tocopherol, 4-methoxyphenol, 4-hydroxyphenyl (meth)acrylate, β-tocopherol, 2,6-di-tert-butylphenol, 2,6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol (butylated hydroxytoluene, BHT), and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate stearyl. Among them, 2,6-di-tert-butyl-4-methylphenol (butylated hydroxytoluene, BHT) is preferred.

[0065] Examples of the phosphorus-based antioxidant include tris(2,5-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris[2,4-bis(1,1-dimethylpropyl)phenyl] phosphite, tris(mono- or di-tert-butylphenyl) phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-di-tridecylphosphite), cycloneopentanylatetetraylbis(2,6-di-tert-butyl-4-methylphenylphosphite), tris(nonylphenyl) phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane, and tristearylphosphite and other trialkylphosphites. Among them, tristearylphosphite and other trialkylphosphites are preferred.

[0066] Examples of the sulfur-based antioxidant include thiodipropionic acid, dilauryl thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl thiodipropionate, distearyl β,β'-thiodibutyrate, thiobis(β-naphthol), thiobis(N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and nickel dibutyldithiocarbamate.

[0067] The content of the antioxidant in layer (A) is preferably 0.05 to 4 parts by mass, more preferably 0.07 to 3 parts by mass, and further preferably 0.08 to 2 parts by mass, based on 100 parts by mass of the amorphous aromatic polyester resin.

[0068] The antioxidant has the effect of inhibiting the transesterification reaction of polyester and polycarbonate. Thus, the layer (A) contains the above-mentioned prescribed amount of antioxidant, so that the foaming caused by the transesterification reaction at the interface between the layer (A) and the color-developing layer (B) can be inhibited. In addition, the antioxidant also has the effect of preventing the film itself from yellowing. From the aspect of suitably exerting this effect, the content of the antioxidant is preferably above the above lower limit, and from the aspect of saturation of this effect, it is preferably set to below the above upper limit.

[0069] In addition, various additives or general-purpose resins may be added to layer (A) in appropriate amounts within the range that does not impair its properties or in order to further improve the physical properties beyond the purpose of the present invention. Examples of additives include: heat stabilizers, process stabilizers, ultraviolet absorbers, light stabilizers, matting agents, impact modifiers, processing aids, metal deactivators, residual polymerization catalyst deactivators, antibacterial / antifungal agents, antistatic agents, lubricants, flame retardants, fillers and other commonly used resin materials, as well as commercially available products for polyester resins such as carbodiimide-based, epoxy-based terminal carboxylic acid end-capping agents, or hydrolysis-proof agents. These may also be added in amounts commonly used depending on the purpose of use.

[0070] As the general-purpose resin, it is preferable to use a resin other than the above-mentioned amorphous aromatic polyester-based resin and having compatibility with the amorphous aromatic polyester-based resin.

[0071] It is optional to add coloring pigments or dyes to layer (A). However, the purpose of the present invention is to visually recognize the high-contrast printing of the color-developing layer (B) through the substantially transparent layer (A), and therefore, it is preferred not to add coloring pigments or the like to layer (A) to reduce the visual recognition.

[0072] (Color layer (B))

[0073] The color developing layer (B) contains a polycarbonate resin and a laser color developing agent.

[0074] Polycarbonate resin

[0075] The polycarbonate resin in the color developing layer (B) is not limited, and bisphenol polycarbonate can be suitably used. Bisphenol polycarbonate refers to a structural unit derived from diol, wherein 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% or more is bisphenol. Bisphenol polycarbonate can be a homopolymer or a copolymer. In addition, bisphenol polycarbonate can be a branched structure, a linear structure, and further a mixture of a branched structure and a linear structure.

[0076] The bisphenol polycarbonate used in the present invention can be produced by any known method such as the phosgene method, the transesterification method, and the pyridine method. As an example, a method for producing a polycarbonate resin by the transesterification method will be described below.

[0077] The transesterification method is a production method in which bisphenol and a carbonic acid diester are added to a basic catalyst, and an acidic substance is further added to neutralize the basic catalyst to carry out melt transesterification polycondensation.

[0078] As a representative example of bisphenol, it is preferable to use 2,2-bis(4-hydroxyphenyl)propane, that is, bisphenol A. In addition, a part or all of bisphenol A may be replaced with other bisphenols.

[0079] Specific examples of bisphenols include 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 1,1-bis(4-hydroxyphenyl)-1-phenylethane (bisphenol AP), 2,2-bis(4-hydroxyphenyl)hexafluoropropane (bisphenol AF), 2,2-bis(4-hydroxyphenyl)butane (bisphenol B), bis(4-hydroxyphenyl)diphenylmethane (bisphenol BP), 2,2-bis(3-methyl-4-hydroxyphenyl)propane (bisphenol C), 1,1-bis(4-hydroxyphenyl)ethane (bisphenol E), bis(4-hydroxyphenyl)methane (bisphenol F), 2,2 -Bis(4-hydroxy-3-isopropylphenyl)propane (bisphenol G), 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (bisphenol M), bis(4-hydroxyphenyl)sulfone (bisphenol S), 1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (bisphenol P), 5,5'-(1-methylethylidene)-bis[1,1'-(biphenyl)-2-ol]propane (bisphenol PH), 1,1-bis(4-hydroxyphenyl)3,3,5-trimethylcyclohexane (bisphenol TMC) and 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z), etc.

[0080] On the other hand, representative examples of carbonic acid diesters include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-tolyl carbonate, dinaphthyl carbonate, bis(biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate, etc. Among them, diphenyl carbonate is particularly preferably used.

[0081] From the perspective of the balance between mechanical properties and molding processability, the mass average molecular weight of the bisphenol polycarbonate used in the present invention is generally in the range of 10000 to 100000, preferably 30000 to 80000. It should be noted that in the present invention, only one bisphenol polycarbonate may be used alone, or two or more bisphenol polycarbonates may be mixed and used.

[0082] Laser color developer

[0083] In the present invention, as a laser color developer, at least a metal oxide is contained. As a metal oxide, there is no limitation as long as it has a laser color development effect, for example, iron oxide, copper oxide, zinc oxide, tin oxide, cobalt oxide, nickel oxide, bismuth oxide, indium oxide, antimony oxide, tungsten oxide, neodymium oxide, mica, hydrotalcite, montmorillonite, bentonite, etc. Among them, from the viewpoint of laser color development effect and cost, it is preferred to use bismuth oxide, a metal oxide containing bismuth and at least one metal selected from Zn, Ti, Al, Zr, Sr and Nb, and more preferably bismuth oxide. Bismuth oxide is well colored even in a small amount, so the effect of the present invention can be fully exerted without damaging the transparency of the color development layer (B).

[0084] The content of the metal oxide as a laser color developing agent in the color developing layer (B) is preferably 135 μg / cm2 per unit area of ​​the laser color developing multilayer film. 2 More preferably 135 μg / cm 2 Above and 250μg / cm 2 Below, more preferably 140 μg / cm 2 Above and 245 μg / cm 2 By making the content of the metal oxide above the above lower limit, the printability can be improved, and by making it below the above upper limit, the transparency of the film can be improved. Here, when the color development layer (B) contains a metal oxide that does not have laser color development ability, the above content value is not included.

[0085] The average particle size of the metal oxide is preferably 10 μm or less, more preferably 5 μm or less. As long as the particle size is 10 μm or less, there is no concern that the transparency is greatly reduced. Here, the particle size refers to the median particle size (d50) obtained by the laser diffraction / scattering method. The lower limit of the average particle size of the metal oxide is not limited, but from the viewpoint of printing performance, it is preferably 0.05 μm or more.

[0086] Examples of commercially available metal oxides include trade names "42-903A" and "42-920A" manufactured by Tokan Material Technology Co., Ltd.

[0087] The color developing layer (B) may also contain laser color developing agents other than metal oxides in addition to the metal oxides as the laser color developing agents mentioned above. Here, the laser color developing agent is not particularly limited as long as it has the function of releasing heat by irradiation of laser light, and may be a so-called self-coloring type color developing agent that develops color by irradiation of laser light, or it may not develop color by itself. The laser color developing agent releases heat, thereby carbonizing at least the surrounding forming materials, and presenting the desired print in the color developing layer (B). If a self-coloring laser color developing agent is further used, the color development of the laser color developing agent is coordinated with the color development caused by the carbide produced by the carbonization of the forming materials of the film, and the color is deep, and a print with excellent visual recognition can be presented. In the case of coloring by the laser color developing agent, its color is not particularly limited. From the viewpoint of visual recognition, it is preferred to use a laser color developing agent that can develop a dark color including black, navy blue, and brown.

[0088] As specific examples of laser color developers other than metal oxides, as metal systems, for example, metals such as iron, copper, zinc, tin, gold, silver, cobalt, nickel, bismuth, antimony, and aluminum, and metal salts such as ferric chloride, ferric nitrate, ferric phosphate, copper chloride, copper nitrate, copper phosphate, zinc chloride, zinc nitrate, zinc phosphate, nickel chloride, nickel nitrate, bismuth subcarbonate, and bismuth nitrate as their salts can be cited. In addition, as metal hydroxide systems, for example, magnesium hydroxide, lanthanum hydroxide, nickel hydroxide, and bismuth hydroxide can be cited. In addition, as metal boride systems, for example, zirconium boride, titanium boride, and lanthanum boride can be cited. In addition, as dye systems, for example, leuco dyes such as fluorescein systems, phenothiazine systems, spiropyran systems, triphenylisophthalic acid lactone systems, and rhodamine lactam systems can be cited.

[0089] The laser color developing agents other than the above metal oxides may be used alone or in combination of two or more. Among the above, hexaborides of rare earth elements have near-infrared absorption capability, and lanthanum hexaboride is preferred because of its excellent laser absorption efficiency.

[0090] When the laser color developer is in the form of particles of a metal compound other than a metal oxide, the average particle size is preferably 10 μm or less, more preferably 5 μm or less. If the particle size is 10 μm or less, there is no concern that the transparency will be significantly reduced.

[0091] It should be noted that when a laser color developer other than a metal oxide is added, the total amount of the metal oxide and the laser color developer other than the metal oxide is preferably not more than the upper limit of the content per unit area mentioned above. In this way, the transparency of the color development layer (B) can be prevented from being reduced.

[0092] Antioxidant content

[0093] The content of the antioxidant in the color developing layer (B) is preferably less than 0.05 parts by mass, and more preferably less than 0.02 parts by mass, relative to 100 parts by mass of the polycarbonate resin. Thus, the transparency of the color developing layer (B) can be prevented from being reduced. In addition, when the transparency of the color developing layer (B) is emphasized, it is preferred that the color developing layer (B) does not contain an antioxidant. It should be noted that in the present invention, "does not contain an antioxidant" means that it does not substantially contain an antioxidant, and when an antioxidant is not intentionally mixed, it also includes a solution containing an antioxidant as an inevitable impurity.

[0094] The present inventors have conducted studies and found that the metal oxide (eg, bismuth oxide) as a laser color developer interacts with the antioxidant, which may explain why the color tone of the sheet becomes black as follows.

[0095] It is known that oxygen-deficient bismuth oxide has good laser color rendering properties, but the inventors have conducted research and found that the color of oxygen-deficient bismuth oxide itself changes depending on the degree of oxygen deficiency. In other words, it is known that oxygen-deficient bismuth oxide (general formula: Bi2O (3-x) , wherein 0.01≤x≤0.3), as the degree of oxygen deficiency x gradually approaches 0.3, bismuth oxide itself will be colored black to gray. In addition, it is expected that the antioxidant increases the oxygen deficiency by reducing the oxygen-deficient bismuth oxide. From this point of view, the inventors have found that the transparency of the color-developing layer (B) can be maintained by limiting the content of the antioxidant in the color-developing layer (B).

[0096] In addition, from the perspective of laser color development, it is preferred that the degree of oxygen deficiency x be less than 0.01. During extrusion film formation, the laser color developer is oxidized over time, so from the perspective of ensuring a predetermined amount of defects, the color development layer (B) may contain an antioxidant in advance within the upper limit of the present invention.

[0097] From the viewpoint of laser color development, it is preferred to use an oxygen-deficient metal oxide as the laser color developing agent. Examples of the oxygen-deficient metal oxide other than the oxygen-deficient bismuth oxide include zinc oxide and tin oxide.

[0098] (Layer composition)

[0099] The layer structure of the laser color-developing multilayer film as the first mode is not particularly limited as long as it has at least layer (A) and color-developing layer (B). For example, there can be a two-layer structure of layer (A) / color-developing layer (B) and a three-layer structure of layer (A) / color-developing layer (B) / layer (A).

[0100] Sublimation thermal transfer image receiving layer (C)

[0101] The laser color developing multilayer film of the first mode may have a sublimation type thermal transfer image receiving layer (C) on at least one side of the multilayer film. The sublimation type thermal transfer image receiving layer (C) is used as the image receiving layer when printing a face photograph or the like in full color and vividly. The image receiving layer is applied to improve the affinity between the printing ink and the sheet surface so that printing can be performed more vividly. It should be noted that examples of the layer structure at this time include: sublimation type thermal transfer image receiving layer (C) / layer (A) / color developing layer (B), layer (A) / color developing layer (B) / sublimation type thermal transfer image receiving layer (C), sublimation type thermal transfer image receiving layer (C) / layer (A) / color developing layer (B) / layer (A), sublimation type thermal transfer image receiving layer (C) / layer (A) / color developing layer (B) / layer (A), sublimation type thermal transfer image receiving layer (C) / layer (A) / color developing layer (B) / layer (A) / sublimation type thermal transfer image receiving layer (C).

[0102] The sublimation thermal transfer image receiving layer (C) may be a conventionally known one, for example, a varnish having a resin as a main component that is easy to transfer or dye a colorant and adding various additives such as a release agent as needed.

[0103] The easily dyeable resin used in the sublimation type thermal transfer image receiving layer (C) can be: polyolefin resins such as polypropylene, halogenated resins such as polyvinyl chloride and polyvinylidene chloride, vinyl resins such as polyvinyl acetate and polyacrylate and their copolymers, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymers of olefins such as ethylene and propylene and other vinyl monomers, monomers or mixtures of ionomers, cellulose derivatives, etc., among which polyester resins and vinyl resins are preferred.

[0104] The sublimation type thermal transfer image receiving layer can be formed by dissolving and dispersing the above resin in an organic solvent, water or the like and then applying the solvent. The organic solvent is not particularly limited and methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, ethyl acetate, cyclohexane, acetone, tetrahydrofuran, or a mixed solvent thereof can be used.

[0105] As additives, stabilizers such as epoxy compounds, ultraviolet absorbers for improving weather resistance, defoamers for improving coating suitability, surfactants, and the like can be used as appropriate.

[0106] In order to prevent the image receiving layer from being thermally fused to the thermal transfer sheet during image formation, a release agent may be mixed into the sublimation type thermal transfer image receiving layer (C). As the release agent, silicone oil, phosphate plasticizer, or fluorine compound may be used, with silicone oil being preferred. The amount of the release agent added is preferably 2 to 30 parts by weight relative to 100 parts by weight of the resin forming the image receiving layer. Instead of adding the release agent to the material mixed with the image receiving layer, a release agent layer may be laminated on the surface of the image receiving layer. Furthermore, other additives such as fluorescent bleaching agents may be added to the image receiving layer as needed.

[0107] In addition, an adhesion coating layer may be appropriately provided between the sublimation type thermal transfer image receiving layer (C) and the layer (A) or the color developing layer (B). Functions of the adhesion coating layer include solvent resistance, barrier properties, adhesive properties, white imparting properties, hiding properties, cushioning properties, antistatic properties, etc.

[0108] In addition, the adhesion coating layer can be formed by dispersing an antistatic conductive material, such as conductive needle crystals (those formed by treating the surface of needle crystals such as potassium titanate, titanium oxide, aluminum borate, silicon carbide, and silicon nitride with a conductive agent) in a binder formed of a thermoplastic resin. By imparting antistatic properties, it is possible to prevent conveying failures such as double-feeding when supplying a thermal transfer image receiving sheet to a thermal transfer printer.

[0109] The sublimation type thermal transfer image receiving layer (C) is usually provided on the surface of the laser color developing multilayer film (the side that becomes the visual recognition side when stacked as a card). The sublimation type thermal transfer image receiving layer (C) can be formed by coating a film on at least one side of the laser color developing multilayer film having the layer (A) and the color developing layer (B) and performing a drying process. As the coating method, a conventionally known method can be adopted.

[0110] Layer thickness

[0111] The thickness of the laser color-developing multilayer film of the first embodiment is not particularly limited, and the thickness of layer (A) is preferably 1 to 50 μm. If the thickness of layer (A) is within the above range, the role of protecting the color-developing layer (B) can be fully exerted. The lower limit of the thickness of layer (A) is more preferably 5 μm or more, and further preferably 10 μm or more. On the other hand, the upper limit is more preferably 45 μm or less, and further preferably 40 μm or less.

[0112] In addition, the thickness of the color developing layer (B) is preferably 50 to 200 μm. If the thickness of the color developing layer (B) is within the above range, laser printing with excellent color development can be performed. The lower limit of the thickness of the color developing layer (B) is more preferably 60 μm or more, and further preferably 70 μm or more. On the other hand, the upper limit is more preferably 180 μm or less, and further preferably 160 μm or less.

[0113] (Properties of laser color-developing multilayer films)

[0114] Total light transmittance

[0115] The laser color developing multilayer film preferably has high transparency, and the total light transmittance according to JIS K7105 is preferably 84% or more, more preferably 85% or more, further preferably 86% or more, and most preferably 88% or more. By improving the transparency of the laser color developing multilayer film, the contrast between the portion other than the printed portion in the color developing layer (B) and the printed portion can be improved.

[0116] Film colorability (L*)

[0117] The lightness L* is measured on a calibrated white plate using a spectrophotometer (model: CM-2500d, manufactured by Konica Minolta) as an index of film colorability. The larger the L*, the closer the film is to transparency. L* is preferably 92 or more, more preferably 95 or more.

[0118] <First embodiment of the method for producing a laser color developing multilayer film>

[0119] As the first method of forming a laser color developing multilayer film, for example, there are the following methods: a method of melt extrusion molding and laminating the resin composition forming each layer in a manner of a desired thickness (coextrusion method); a method of forming each layer into a film with a desired thickness and laminating it; or a method of melt extrusion to form a plurality of layers and laminating a separately formed film thereon, etc. Among them, lamination by melt extrusion molding is preferred from the aspects of productivity and cost.

[0120] Specifically, the resin compositions constituting each layer are prepared separately, or formed into pellets as needed, and are respectively put into each hopper of a multilayer T-die extruder connected to a T-die. Further, melting is performed at a temperature range of 200 to 300° C., and multilayer T-die melt extrusion molding is performed. Then, cooling and solidification are performed on a cooling roller or the like. In this way, a multilayer film can be formed. It should be noted that the multilayer film for laser printing disclosed in the present invention can be formed by a known method and is not limited to the above method.

[0121] <Second Embodiment of Laminated Body for Plastic Card>

[0122] The second embodiment of the laminate for plastic card comprises the laser color developing multilayer film of the first embodiment. In addition, the second embodiment of the laminate for plastic card of the present invention preferably comprises the laser color developing multilayer film of the first embodiment as a surface material. Examples of plastic cards include: ID cards such as driver's licenses, insurance cards, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration cards, cash cards, credit cards, label cards, IC cards, magnetic cards, vehicle inspection certificates, prepaid cards, etc.

[0123] Specifically, as the structure of the laminate for plastic card of the second embodiment, it is preferable that Figure 1 A three-layer laminate 20A composed of a laser color developing multilayer film 1 / a core sheet 2 / a laser color developing multilayer film 1, or Figure 1 The five-layer laminate 20B shown in (b) is composed of protective layer 4 / laser color developing multilayer film 1 / core sheet 2 / laser color developing multilayer film 1 / protective layer 4.

[0124] The core sheet 2 is preferably a sheet formed by laminating at least one layer of sheets by melt extrusion molding, preferably with polycarbonate resin and / or amorphous aromatic polyester resin as the main component, and containing at least one colorant of 1% by mass relative to 100% by mass of the resin of the main component. The total thickness of the core sheet 2 is preferably 400 to 700 μm. For the colorant of the core sheet, as white pigments, titanium oxide, barium oxide, zinc oxide can be mentioned, as yellow pigments, iron oxide, titanium yellow can be mentioned, as red pigments, iron oxide can be mentioned, and as blue pigments, cobalt blue ultramarine can be mentioned. However, in order to improve the contrast, it is preferably a light coloring and light color system. Among the above colorants, it is more preferred to add a colorant of a resin such as a white dye or pigment with a conspicuous contrast.

[0125] The protective layer 4 is a layer for suppressing the foaming of the laser printed part due to the laser energy irradiation, so-called "expansion". The resin used in the protective layer 4 is not particularly limited, and a highly transparent resin is preferred, for example, polycarbonate resin, amorphous aromatic polyester resin, a mixture of polycarbonate resin and amorphous aromatic polyester resin, etc.

[0126] <Laminate for electronic passport of the third aspect>

[0127] The laminate for electronic passport of the third aspect comprises the laser color developing multilayer film of the first aspect. In addition, the laminate for electronic passport of the third aspect of the present invention preferably comprises the laser color developing multilayer film of the first aspect as a surface material.

[0128] Specifically, as the structure of the laminate for electronic passport of the third embodiment, it is preferable that Figure 2A five-layer laminate 10A consisting of laser color developing multilayer film 1 / core sheet 2 / hinge sheet 3 / core sheet 2 / laser color developing multilayer film 1 as shown in (a), or Figure 2 The seven-layer laminate 10B shown in (b) is composed of protective layer 4 / laser color developing multilayer film 1 / core sheet 2 / hinge sheet 3 / core sheet 2 / laser color developing multilayer film 1 / protective layer 4.

[0129] The hinged sheet 3 in the laminated body for electronic passport of the third mode is a sheet for taking on the following functions: (1) the text, figure, mark or information written by laser marking on the laser color developing multilayer film; (2) the information such as images and text printed by printing on the core sheet; and (3) various information stored in the storage medium such as IC chip, i.e., the sheet provided for storing various information, i.e., the so-called input sheet provided with IC chip, etc., is firmly bound to the cover of the passport and other visa sheets. Therefore, it is preferred to have strong heat welding property, moderate flexibility, heat resistance in the heat welding process, etc. For example, when the hinged sheet 3 is sewn and bound to the cover (of the passport), etc., in most cases, the tearing and tensile strength of the sewing part are excellent, and the hinge part has light resistance and heat resistance. Furthermore, sometimes it is also required to have resistance to repeated bending, in other words, excellent hinge characteristics. Therefore, as a hinged sheet 3 that meets this purpose, the following raw materials are suitable.

[0130] The hinged sheet 3 that plays such a role is preferably a sheet formed of at least one selected from thermoplastic polyester resin, thermoplastic polyester elastomer, thermoplastic polyamide resin, thermoplastic polyamide elastomer, thermoplastic polyurethane resin, and thermoplastic polyurethane elastomer. In addition, the hinged sheet 3 is also preferably a fabric of polyester resin and / or polyamide resin, or a laminated sheet including the aforementioned fabric and a sheet formed of at least one selected from thermoplastic polyester resin, thermoplastic polyester elastomer, thermoplastic polyamide resin, thermoplastic polyamide elastomer, thermoplastic polyurethane resin, and thermoplastic polyurethane elastomer.

[0131] The core sheet 2 is the same as described above except that the total thickness is preferably 50 to 200 μm. The protective layer 4 is the same as described above.

[0132] <Laser color-developing multilayer film of the fourth aspect>

[0133] The laser color-developing multilayer film of the fourth embodiment of the present invention is a laser color-developing multilayer film, which is used for passports, IC cards, magnetic cards, driver's licenses, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration cards, vehicle inspection certificates, label cards, prepaid cards, cash cards and credit cards. It is a laser color-developing multilayer film having at least two layers of a layer (X) and a color-developing layer (Y), one of the aforementioned layer (X) and the aforementioned color-developing layer (Y) contains a polyester resin as a resin component, and the other layer contains a polycarbonate resin as a resin component,

[0134] The layer (X) contains an antioxidant and / or an ester exchange inhibitor, and the content of the antioxidant and / or the ester exchange inhibitor is 0.01 parts by mass or more based on 100 parts by mass of the resin component.

[0135] The color developing layer (Y) contains a laser color developing agent, and the laser color developing agent is a metal oxide. The content of the antioxidant in the color developing layer (Y) is less than 0.1 parts by mass based on 100 parts by mass of the resin component.

[0136] In the laser color-developing multilayer film of the fourth mode, as long as one of the layer (X) and the color-developing layer (Y) contains a polyester resin as a resin component and the other layer contains a polycarbonate resin as a resin component, the layer (X) may contain a polyester resin and the color-developing layer (Y) may contain a polycarbonate resin, or conversely, the layer (X) may contain a polycarbonate resin and the color-developing layer (Y) may contain a polyester resin.

[0137] Among them, from the viewpoint of preventing coloration of the entire multilayer film and improving the contrast between the printed portion and the portion other than the printed portion, it is preferred that the layer (X) contains a polyester resin and the color development layer (Y) contains a polycarbonate resin.

[0138] (Polyester resin)

[0139] The polyester resin is not particularly limited and may include crystalline or amorphous aliphatic polyester resins, crystalline or amorphous alicyclic polyester resins, and crystalline or amorphous aromatic polyester resins. Among them, amorphous aromatic polyester resins are preferably used from the perspectives of transparency and cost.

[0140] As the amorphous aromatic polyester-based resin, the same as that used in the layer (A) of the laser color developing multilayer film of the first embodiment can be used.

[0141] (Polycarbonate resin)

[0142] As the polycarbonate resin, the same polycarbonate resin as that used in the color developing layer (B) of the laser color developing multilayer film of the first embodiment can be used.

[0143] (Layer(X))

[0144] The layer (X) contains an antioxidant and / or an interesterification inhibitor in addition to the above-mentioned resin component.

[0145] Antioxidants

[0146] As the antioxidant, the same antioxidant as that used in the laser color developing multilayer film of the first embodiment can be used.

[0147] ·Transesterification inhibitors

[0148] The transesterification inhibitor is not particularly limited as long as it can inhibit the transesterification reaction between the polyester resin and the polycarbonate resin, and includes phosphorous acid, phosphoric acid, phosphite, phosphate ester, and metal salts thereof. Among them, phosphate ester compounds are preferred, and organic phosphate ester compounds are particularly preferred.

[0149] The organophosphate compound has a partial structure in which 1 to 3 alkoxy groups or aryloxy groups are bonded to the phosphorus atom. It should be noted that these alkoxy groups and aryloxy groups may be further bonded to a substituent. Preferably, the metal salt of the organophosphate compound is a metal salt, and more preferably, at least one metal selected from the group consisting of Ia, IIa, IIb, IIIa and IIIb of the periodic table, among which magnesium, barium, calcium, zinc and aluminum are further preferred, and magnesium, calcium or zinc is particularly preferred.

[0150] In the present invention, it is preferred to use an organic phosphate compound represented by any one of the following general formulas (1) to (5), more preferably an organic phosphate compound represented by any one of the following general formulas (1) to (4), and even more preferably an organic phosphate compound represented by the following general formula (1) or (2). Two or more organic phosphate compounds may be used in combination.

[0151]

[0152] In the general formula (1), R 1 ~R 4 Each independently represents an alkyl group or an aryl group. 1 Represents an alkaline earth metal or zinc.

[0153]

[0154] In the general formula (2), R 5 represents an alkyl or aryl group, M 2 Represents an alkaline earth metal or zinc.

[0155]

[0156] In the general formula (3), R 6 ~R 11 Each independently represents an alkyl group or an aryl group.3 It represents a metal atom that becomes a trivalent metal ion.

[0157]

[0158] In the general formula (4), R 12 ~R 14 Each independently represents an alkyl group or an aryl group. 4 represents a metal atom that becomes a trivalent metal ion, and two M 4 They may be the same or different.

[0159] O=P(OH) n (OR 15 ) 3-n (15)

[0160] In the general formula (5), R 15 represents an alkyl group or an aryl group. n represents an integer of 0 to 2. It should be noted that when n is 0 or 1, 2 or 3 R 15 Can be the same or different.

[0161] In the general formulas (1) to (5), R 1 ~R 15 It is usually an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. From the viewpoints of thermal stability, chemical resistance, and heat and moisture resistance, an alkyl group having 2 to 25 carbon atoms is preferred, and an alkyl group having 6 to 23 carbon atoms is most preferred. Examples of the alkyl group include octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, hexadecyl, and octadecyl. In addition, M in the general formula (1) and (2) 1 、M 2 Preferably zinc, M in the general formula (3) and (4) 3 、M 4 Aluminum is preferred.

[0162] Preferred specific examples of the organic phosphate compound include bis(acid distearyl phosphate) zinc salt as the compound of general formula (1), acid monostearyl phosphate zinc salt as the compound of general formula (2), tri(acid distearyl phosphate) aluminum salt as the compound of general formula (3), salt of one acid monostearyl phosphate and two acid monostearyl phosphate aluminum salts as the compound of general formula (4), acid monostearyl phosphate, acid distearyl phosphate, etc. as the compound of general formula (5). Among them, bis(acid distearyl phosphate) zinc salt and acid monostearyl phosphate zinc salt are more preferred. They can be used alone or as a mixture.

[0163] As the organic phosphate compound, zinc salts of stearyl acid phosphates such as bis(distearyl acid phosphate) zinc salts as zinc salts of the organic phosphate compound represented by the general formula (1) and monostearyl acid phosphate zinc salts as zinc salts of the organic phosphate compound represented by the general formula (2) are preferably used, from the viewpoints of having a very high transesterification inhibitory effect, good thermal stability during molding, excellent moldability, the ability to set the temperature of the extruder etc. at a high level and stable molding, and excellent hydrolysis resistance and impact resistance. Examples of these commercially available products include "JP-518Zn" manufactured by Johoku Chemical Industry Co., Ltd.

[0164] In addition, organic phosphite compounds and organic phosphonite compounds can also be used. Preferred examples of the organic phosphite compounds include compounds represented by the following general formula (6).

[0165] R 16 OP (OR 17 ) (OR 18 ) (6)

[0166] (In general formula (6), R 16 , R 17 and R 18 are hydrogen atoms, alkyl groups having 1 to 30 carbon atoms, or aryl groups having 6 to 30 carbon atoms, R 16 , R 17 and R 18 At least one of them is an aryl group having 6 to 30 carbon atoms. )

[0167] Examples of the organic phosphite compound include triphenyl phosphite, tris(nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris(2-ethylhexyl) phosphite, tritridecyl phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl monotridecyl phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetratridecyl pentaerythritol tetraphosphite, hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl ditridecyl phosphite), tetratridecyl 4, 4'-isopropylidene diphenyl diphosphite, bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, dilaurylpentaerythritol diphosphite, distearylpentaerythritol diphosphite, tris(4-tert-butylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, etc. Among them, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred.

[0168] Preferred examples of the organic phosphite compound include compounds represented by the following general formula (7).

[0169] R 19 -P(OR 20 ) (OR 21 ) (7)

[0170] (In general formula (7), R 19 , R 20 and R 21 are hydrogen atoms, alkyl groups having 1 to 30 carbon atoms, or aryl groups having 6 to 30 carbon atoms, R 19 , R 20 and R 21 At least one of them is an aryl group having 6 to 30 carbon atoms. )

[0171] Examples of the organic phosphite compound include tetrakis(2,4-di-isopropylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-n-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphite, and tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite. Phenyl diphosphite, tetrakis(2,6-di-isopropylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,6-di-n-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphite and tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphite, etc.

[0172] The content of the antioxidant and / or transesterification inhibitor in the layer (X) is 0.01 parts by mass or more, preferably 0.05 parts by mass or more and 4 parts by mass or less, more preferably 0.07 parts by mass or more and 3 parts by mass or less, and further preferably 0.08 parts by mass or more and 2 parts by mass or less, relative to 100 parts by mass of the above-mentioned resin component. It should be noted that the antioxidant and the transesterification inhibitor may be used alone or in combination.

[0173] Antioxidants and transesterification inhibitors have the effect of suppressing the transesterification reaction of polyester resin and polycarbonate resin. Thus, by containing the above-mentioned prescribed amount of antioxidants and / or transesterification inhibitors in layer (X), the foaming caused by the transesterification reaction at the interface of layer (X) and color developing layer (Y) can be suppressed. In addition, antioxidants and transesterification inhibitors also have the effect of preventing the yellowing of the film itself. From the aspect of suitably exerting this effect, the content of antioxidants and / or transesterification inhibitors is preferably above the above-mentioned lower limit, and from the aspect of saturation of this effect, it is preferably set to below the above-mentioned upper limit.

[0174] The aspect that various additives or general-purpose resins, or coloring pigments and dyes may be added to the layer (X) is the same as that of the laser color developing multilayer film of the first embodiment.

[0175] (Color layer (Y))

[0176] The color developing layer (Y) contains a laser color developing agent in addition to the above-mentioned resin component.

[0177] Laser color developer

[0178] The laser color developing agent is the same as that in the color developing layer (B) of the laser color developing multilayer film of the first embodiment.

[0179] ·Content of laser developer

[0180] The content of the laser color developing agent per unit area of ​​the laser color developing multilayer film is also the same as the content in the color developing layer (B) of the laser color developing multilayer film of the first embodiment.

[0181] Antioxidant content

[0182] The content of the antioxidant in the color developing layer (Y) is less than 0.1 parts by mass, preferably less than 0.07 parts by mass, more preferably less than 0.05 parts by mass, and further preferably less than 0.02 parts by mass, relative to 100 parts by mass of the polycarbonate resin. This can prevent the reduction of the transparency of the color developing layer (Y) and the coloring of the film. In addition, when the transparency of the color developing layer (Y) and the coloring prevention are emphasized, the color developing layer (Y) preferably does not contain an antioxidant.

[0183] (Layer composition)

[0184] The layer structure of the laser color-developing multilayer film as the fourth mode is not particularly limited as long as it has at least layer (X) and color-developing layer (Y). For example, it can be a two-layer structure of layer (X) / color-developing layer (Y) or a three-layer structure of layer (X) / color-developing layer (Y) / layer (X).

[0185] Sublimation thermal transfer image receiving layer (C)

[0186] The laser color developing multilayer film of the fourth embodiment may include a sublimation type thermal transfer image receiving layer (C) on at least one side of the multilayer film. The sublimation type thermal transfer image receiving layer (C) is the same as that of the laser color developing multilayer film of the first embodiment.

[0187] (use)

[0188] As the uses of the fourth mode of laser color-developing multilayer film, there are: passports, IC cards, magnetic cards, driver's licenses, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration certificates, vehicle inspection certificates, label cards, prepaid cards, cash cards and credit cards.

[0189] <Method of using the laser color developing multilayer film of the fourth aspect>

[0190] The laser color developing multilayer film of the fourth mode can be used as a passport, IC card, magnetic card, driver's license, residence permit, qualification certificate, employee ID, student ID, personal number card, seal registration card, vehicle inspection certificate, label card, prepaid card, cash card and credit card. As described in the second and third modes, it can be combined with a core sheet, hinge sheet and other sheets required for new uses to form a laminate suitable for each use, so that it can be used for various uses.

[0191] Example

[0192] Hereinafter, although an Example and a comparative example are shown, this invention is not limited thereto at all.

[0193] <Materials>

[0194] The materials used in each of the Examples and Comparative Examples are as follows.

[0195] (Amorphous aromatic polyester resin (PETG))

[0196] As PETG, GN001 (manufactured by Eastman Chemical Company) was used.

[0197] (Polycarbonate resin (PC))

[0198] As PC, Novarex 7027 (manufactured by Mitsubishi Engineering-Plastics Corporation) was used.

[0199] (Antioxidant)

[0200] As the phenolic antioxidant, butylated hydroxytoluene (BHT) was used.

[0201] As the phosphorus-based antioxidant, tristearyl phosphite was used.

[0202] (Laser color developer)

[0203] As a laser color developer, bismuth oxide (average particle size: 1 μm, specific gravity: 8.9 g / cm 3 ).

[0204] In the following examples and comparative examples, the layer (A) of the first embodiment corresponds to the layer (X) of the fourth embodiment, and the color development layer (B) of the first embodiment corresponds to the color development layer (Y) of the fourth embodiment.

[0205] <Example 1>

[0206] As layer (A), 0.08 parts by mass of a phenolic antioxidant and 0.08 parts by mass of a phosphorus antioxidant were dry-blended with respect to 100 parts by mass of PETG, and extruded at 240° C. from two 3-layer manifold nozzles using an extruder as the first and third layers (two outer layers).

[0207] As the color development layer (B), 0.30 parts by mass of a laser color developer was dry-blended with 100 parts by mass of PC and extruded from the above-mentioned nozzle of the extruder at 240° C. as a second layer (intermediate layer).

[0208] The extruded film was quenched on a casting roll at about 80° C. to obtain a multilayer film having a layer (A) of 20 μm, a color-developing layer (B) of 90 μm, and a total thickness of 130 μm.

[0209] <Example 2>

[0210] A multilayer thin film was obtained in the same manner as in Example 1 except that the amount of the laser color developer in the color developing layer (B) was changed to 0.23 parts by mass.

[0211] <Example 3>

[0212] A multilayer thin film was obtained in the same manner as in Example 1 except that the amount of the laser color developer in the color developing layer (B) was changed to 0.19 parts by mass.

[0213] <Example 4>

[0214] A multilayer film was obtained in the same manner as in Example 1 except that the amount of the laser color developer in the color developing layer (B) was 0.19 parts by mass, the thickness of the layer (A) was 14 μm, and the thickness of the color developing layer (B) was 102 μm.

[0215] <Example 5>

[0216] A multilayer film was obtained in the same manner as in Example 4 except that the amount of phenolic antioxidant and phosphorus antioxidant in layer (A) was 0.05 mass parts and the amount of laser color developer in color developing layer (B) was 0.16 mass parts.

[0217] <Example 6>

[0218] A multilayer thin film was obtained in the same manner as in Example 4 except that 0.01 parts by mass of a phenolic antioxidant and 0.01 parts by mass of a phosphorus antioxidant were further added to the color development layer (B).

[0219] <Example 7>

[0220] On one side of the multilayer film of Example 1, a sublimation type thermal transfer image receiving layer (C) obtained by mixing a vinyl chloride / vinyl acetate copolymer and a MEK / cyclohexane mixed solvent at a mass ratio of copolymer: mixed solvent of 20:80 was provided so as to have a thickness of 2 μm after drying.

[0221] <Example 8>

[0222] As layer (A), 0.08 parts by mass of a phenolic antioxidant and 0.08 parts by mass of a phosphorus antioxidant were dry-blended with respect to 100 parts by mass of PETG, and extruded at 240° C. from two 3-layer manifold nozzles using an extruder as the first and third layers (two outer layers).

[0223] As the color development layer (B), 0.30 parts by mass of a laser color developer was dry-blended with 100 parts by mass of PC and extruded from the above-mentioned nozzle of the extruder at 240° C. as a second layer (intermediate layer).

[0224] The extruded film was quenched on a casting roll at about 80°C to obtain a multilayer film having a layer (A) of 23 μm, a color-developing layer (B) of 104 μm, and a total thickness of 150 μm.

[0225] <Example 9>

[0226] A multilayer film was obtained in the same manner as in Example 8 except that the laser developer was used in 0.19 parts by mass in the color developing layer (B), the thickness of layer (A) was 11 μm, the color developing layer (B) was 78 μm, and the total thickness was 100 μm.

[0227] <Comparative Example 1>

[0228] PETG was used as the layer (A), and was extruded at 240° C. from two types of three-layer manifold nozzles using an extruder as the first layer and the third layer (two outer layers).

[0229] In addition, as the color development layer (B), 0.05 mass parts of laser color developer, 0.12 mass parts of phenolic antioxidant and 0.12 mass parts of phosphorus antioxidant were dry-blended with respect to 100 mass parts of PC, and extruded from the above-mentioned nozzle of the extruder at 240°C as the second layer (intermediate layer).

[0230] The extruded film was quenched on a casting roll at about 80° C. to obtain a multilayer film having a layer (A) of 12.5 μm, a color-developing layer (B) of 25 μm, and a total thickness of 50 μm.

[0231] <Comparative Example 2>

[0232] A multilayer thin film was obtained in the same manner as in Comparative Example 1 except that the thickness of the layer (A) was 25 μm, the thickness of the color-developing layer (B) was 50 μm, and the total thickness was 100 μm.

[0233] <Comparative Example 3>

[0234] PETG was used as the layer (A), and was extruded at 240° C. from two types of three-layer manifold nozzles using an extruder as the first layer and the third layer (two outer layers).

[0235] In addition, as the color development layer (B), 0.19 mass parts of laser color developer, 0.08 mass parts of phenolic antioxidant and 0.08 mass parts of phosphorus antioxidant were dry-blended with respect to 100 mass parts of PC, and extruded from the above-mentioned nozzle of the extruder at 240°C as the second layer (intermediate layer).

[0236] The extruded film was quenched on a casting roll at about 80°C to obtain a multilayer film having a layer (A) of 14 μm, a color-developing layer (B) of 102 μm, and a total thickness of 130 μm.

[0237] <Comparative Example 4>

[0238] PETG was used as the layer (A), and was extruded at 240° C. from two types of three-layer manifold nozzles using an extruder as the first layer and the third layer (two outer layers).

[0239] As the color development layer (B), 0.15 parts by mass of a phenolic antioxidant and 0.15 parts by mass of a phosphorus antioxidant were dry-blended with respect to 100 parts by mass of PC and extruded from the above-mentioned nozzle of the extruder at 240° C. as a second layer (intermediate layer).

[0240] The extruded film was quenched on a casting roll at about 80° C. to obtain a multilayer film having a layer (A) of 25 μm, a color-developing layer (B) of 50 μm, and a total thickness of 100 μm.

[0241] <Comparative Example 5>

[0242] A multilayer thin film was obtained in the same manner as in Comparative Example 4 except that no antioxidant was added to the color development layer (B).

[0243] <Evaluation>

[0244] The following evaluations were performed on the multilayer films obtained in the above-mentioned Examples and Comparative Examples.

[0245] (Laser color development dose per unit area)

[0246] The laser color developing dose per unit area was calculated using the following formula.

[0247] Laser color development dose per unit area (μg / cm 2 ) = specific gravity of laser developer (μg / cm 3 )×mass ratio of the laser developer in the layer containing the laser developer (%)×thickness of the layer containing the laser developer (cm),

[0248] For example, in the case of Example 1, calculation is performed as follows.

[0249] 8.9×10 6 (Specific gravity) × 0.003 (Mass ratio) × 90 × 10 -4 (Thickness) = 240.3

[0250] (Thin film foaming)

[0251] The produced multilayer film was visually observed and the presence or absence of bubbles was evaluated based on the following criteria.

[0252] ○: No bubbles in the multi-layer film

[0253] ×: Bubbles are visible in the multilayer film

[0254] (Thin film colorability (L*))

[0255] The chromaticity L* of the produced multilayer film was measured on a calibrated white plate using a spectrophotometer (model: CM-2500d, manufactured by Konica Minolta Co., Ltd.) and it was determined that L* was preferably 92 or more, more preferably 95 or more.

[0256] (Transparency (total light transmittance))

[0257] The total light transmittance was measured using a haze meter (model: TC-HIIIDPK, manufactured by Tokyo Denshoku Co., Ltd.) in accordance with JIS K7105.

[0258] It is judged that the total light transmittance is preferably 84% or more, more preferably 85% or more.

[0259] (Printability (reflection density value))

[0260] The card made of the multilayer film was laser printed at 51 μm / step×80% using CLM-20 manufactured by Nidec Copal Corporation, and the reflection density was measured using eXact manufactured by X-Rite Co. It was determined that the reflection density was preferably 1.4 or more, more preferably 1.5 or more.

[0261] It should be noted that the card is obtained as follows: a multilayer film and a chip with a thickness of 280 μm (PETG: titanium oxide = 88:12 by mass ratio) are overlapped in the order of multilayer film / chip / chip / multilayer film, and then the obtained stack is punched into a card shape using a 120°C hot press.

[0262] [Table 1]

[0263]

[0264] Industrial Applicability

[0265] The laser color-developing multilayer film of the present invention can improve the contrast between the printed part and the parts other than the printed part. Therefore, it can be used as a constituent material for laminated bodies for plastic cards such as driver's licenses, insurance cards, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration cards, cash cards, credit cards, label cards, IC cards, magnetic cards, vehicle inspection certificates, prepaid cards, etc., which need to be prevented from tampering and forgery, or as a constituent material for laminated bodies for passports.

[0266] Description of Reference Numerals

[0267] 1: Laser color rendering multilayer film

[0268] 2: Core sheet

[0269] 3: hinged piece

[0270] 4: Protective layer

[0271] 20A, 20B: Laminated body for plastic card

[0272] 10A, 10B: Laminated body for electronic passport

Claims

1. A laser color developing multilayer film comprising at least two layers of a layer (A) and a color developing layer (B), The layer (A) comprises an amorphous aromatic polyester resin and an antioxidant, wherein the content of the antioxidant is 0.05 to 4 parts by mass based on 100 parts by mass of the amorphous aromatic polyester resin. The color developing layer (B) comprises a polycarbonate resin and a laser color developing agent, the laser color developing agent is a metal oxide, and the color developing layer (B) does not contain an antioxidant. The metal oxide is a bismuth-based metal oxide, The content of the laser developer per unit area is 135-250 μg / cm 2 .

2. The laser color rendering multilayer film according to claim 1, wherein: The metal oxide is an oxygen-deficient bismuth-based metal oxide.

3. The laser color rendering multilayer film according to claim 1, wherein: The antioxidant is butylated hydroxytoluene and / or trialkyl phosphite.

4. The laser color rendering multilayer film according to claim 1, wherein the total light transmittance is greater than 84%. 5 . The laser color-developing multilayer film according to claim 1 , wherein the brightness L* measured on a calibrated white plate using a spectrophotometer is 92 or more.

6. The laser color rendering multilayer film according to claim 1, wherein: The color development layer (B) has a thickness of 50 μm or more and 200 μm or less.

7. The laser color rendering multilayer film according to claim 1, wherein: A sublimation type thermal transfer image receiving layer (C) is also provided on at least one surface of the laser color developing multilayer film. 8 . A laminate for plastic cards, comprising the laser color developing multilayer film according to claim 1 . 9 . A laminate for an electronic passport, comprising the laser color developing multilayer film according to claim 1 .

10. A laser color developing multilayer film, which is used for passports, IC cards, magnetic cards, driver's licenses, residence permits, qualification certificates, employee cards, student cards, personal number cards, seal registration cards, vehicle inspection certificates, label cards, prepaid cards, cash cards and credit cards, and which is a laser color developing multilayer film having at least two layers of a layer (X) and a color developing layer (Y), One of the layer (X) and the color development layer (Y) contains a polyester resin as a resin component, and the other layer contains a polycarbonate resin as a resin component, The layer (X) contains an antioxidant and / or an ester exchange inhibitor, wherein the content of the antioxidant and / or the ester exchange inhibitor is 0.01 parts by mass or more relative to 100 parts by mass of the resin component. The color developing layer (Y) contains a laser color developing agent, the laser color developing agent is a metal oxide, and the color developing layer (Y) does not contain an antioxidant. The metal oxide is a bismuth-based metal oxide, The content of the laser developer per unit area is 135-250 μg / cm 2 .

11. The laser color rendering multilayer film according to claim 10, wherein: The content of the antioxidant and / or transesterification inhibitor in the layer (X) is 0.05 to 4 parts by mass based on 100 parts by mass of the resin component.

12. The laser color rendering multilayer film according to claim 10, wherein: The metal oxide is oxygen-deficient.

13. The laser color rendering multilayer film according to any one of claims 10 to 12, wherein: The metal oxide is an oxygen-deficient bismuth-based metal oxide.

14. The laser color rendering multilayer film according to any one of claims 10 to 12, wherein: The layer (X) comprises a polyester resin, and the color development layer (Y) comprises a polycarbonate resin.

15. The laser color rendering multilayer film according to any one of claims 10 to 12, wherein: The polyester-based resin is an amorphous polyester-based resin.

16. A passport, an IC card, a magnetic card, a driver's license, a residence permit, a qualification certificate, an employee card, a student card, a personal number card, a seal registration card, a vehicle inspection certificate, a label card, a prepaid card, a cash card and a credit card, which has the laser color-rendering multilayer film according to any one of claims 10 to 15.

17. A method of using the laser color-developing multilayer film described in any one of claims 10 to 15 as a passport, IC card, magnetic card, driver's license, residence permit, qualification certificate, employee ID, student ID, personal number card, seal registration certificate, vehicle inspection certificate, label card, prepaid card, cash card and credit card.

Images