Resin composition, resin sheet, multilayer body, and card

Abstract

The present invention provides a resin composition capable of producing a thin resin sheet having excellent light-shielding properties and excellent laminating properties, as well as a resin sheet, a multilayer body, and a card using the resin composition. The present invention provides a resin composition comprising 25 to 79.5 parts by mass of a polycarbonate resin, 0.5 to 40 parts by mass of a polyester, and 20 to 50 parts by mass of titanium oxide.

Description

Technical Field

[0001] The present invention relates to a resin composition, a resin sheet, a multilayer body and a card. Background Art

[0002] Currently, cards using resin sheets or multilayer bodies including resin sheets are being used for security cards such as ID cards, e-passports, and contactless IC cards.

[0003] Among them, as an example of the layer structure of a security card, Figure 1 The multilayer body shown. Figure 1 In (A) and (B), 10 represents a multilayer body, 11 represents a covering layer (transparent resin sheet), and 12 and 13 represent white core layers. The multilayer body 10 sometimes also includes a laser marking layer, etc. In addition, an IC chip or antenna is usually installed in the layer or between the layers of the white core layers 12 and 13. Moreover, by using the white core layers 12 and 13 with shielding properties, it is possible to form a structure in which the IC chip or antenna cannot be seen from the outside of the card. These layers ( Figure 1 (A)) is formed into a multilayer body ( Figure 1 (B) Such a security card is described in Patent Document 1, for example.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 163889 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] In recent years, research has also been conducted on security cards having transparent windows. Figure 2 An example of a security card (multi-layer body) with a transparent window is shown. Figure 2 In (A) to (C), 20 represents a security card (multi-layer body), 21 represents a cover layer (transparent resin sheet), 22 represents a white core layer, 23 represents a transparent resin sheet, and 24 represents a transparent window. The transparent window 24 is provided on the security card for the purpose of, for example, preventing forgery or improving the appearance design, and is a transparent window portion of a portion of the card surface into which the card is introduced. As a method for manufacturing a multi-layer body having a transparent window 24, there is a method of providing an opening portion (an area where the white core layer does not exist) 25 in the white core layer 22 when stacking the layers. Figure 2 (A)) is a method of bonding the layers by heat pressing. By doing so, during heat pressing, a portion of the transparent resin of the cover layer (transparent resin sheet) 21 or the transparent resin sheet 23 flows into the above-mentioned opening 25 ( Figure 2 (B)), forming a transparent window 24 ( Figure 2 (C)). When manufacturing a transparent window by this method, in order to allow the transparent resin to fully fill the opening 25, the white core layer 22 needs to be thinned. However, it was found that when the white core layer 22 is thinned, the light shielding property originally required by the white core layer 22 is deteriorated. In particular, in order to provide the transparent window 24, the layer adjacent to the white core layer 22 cannot be Figure 2 The white core layer (the layer shown in the figure 23) must be a transparent resin sheet 23. This means that if the light-shielding properties of the white core layer 22 deteriorate, the IC chip or antenna installed inside the security card (multi-layer body) will also be visible. Therefore, a thin resin sheet with excellent shielding properties is required. Furthermore, this thin resin sheet must be able to laminate with the aforementioned transparent resin sheet.

[0009] The present invention aims to solve the above-mentioned technical problems and to provide a resin composition capable of providing a thin resin sheet having excellent light shielding performance and excellent lamination performance, as well as a resin sheet, a multilayer body and a card using the resin composition.

[0010] Technical solutions to technical problems

[0011] The inventors of the present invention have conducted research to solve the above technical problems and found that the above technical problems can be solved by the following technical solutions.

[0012] <1> A resin composition comprising 25 to 79.5 parts by mass of a polycarbonate resin, 0.5 to 40 parts by mass of a polyester, and 20 to 50 parts by mass of titanium oxide.

[0013] <2> The resin composition according to <1>, wherein the glass transition temperature of the resin composition measured by the method (DSC) specified in JIS K7121:1987 is 100 to 155°C.

[0014] <3> The resin composition according to <1> or <2>, wherein the melt volume flow rate (MVR) of the resin composition measured in accordance with JIS K7210 is 2.0 to 50.0 cm 3 / 10min.

[0015] <4> The resin composition according to any one of <1> to <3>, wherein the polycarbonate resin has a viscosity average molecular weight of 20,000 to 35,000.

[0016] <5> The resin composition according to any one of <1> to <4>, further comprising a colorant other than titanium oxide at a ratio of 5 to 150 ppm by mass.

[0017] <6> The resin composition according to <5>, wherein the other colorant includes a colorant having a maximum absorption in the wavelength range of 450 to 650 nm.

[0018] <7> The resin composition according to <5>, wherein the other colorant contains carbon black.

[0019] <8> The resin composition according to <5> or <6>, wherein the other colorant includes a dye.

[0020] <9> The resin composition according to any one of <1> to <8>, further comprising an antioxidant at a ratio of 0.01 to 0.2% by mass.

[0021] <10> The resin composition according to any one of <1> to <9>, further comprising an antistatic agent.

[0022] <11> The resin composition according to any one of <1> to <10>, wherein the polyester comprises an aliphatic polyester, and the content of the aliphatic polyester is 1 to 9 parts by mass.

[0023] <12> The resin composition according to <11>, wherein the aliphatic polyester includes a structural unit derived from a lactone compound.

[0024] <13> The resin composition according to <11>, wherein the aliphatic polyester comprises polycaprolactone.

[0025] <14> The resin composition according to any one of <1> to <10>, wherein the polyester comprises an aromatic polyester, and the content of the aromatic polyester is 10 to 40 parts by mass.

[0026] <15> The resin composition according to any one of <1> to <14>, which is used for a card.

[0027] <16> A resin sheet formed from the resin composition according to any one of <1> to <15>.

[0028] <17> The resin sheet according to <16>, having a thickness of 20 to 200 μm.

[0029] <18> The resin sheet according to <16> or <17>, wherein the total light transmittance is 0 to 20%.

[0030] <19> The resin sheet according to any one of <16> to <18>, wherein T×t is 200 to 750, assuming that the total light transmittance of the resin sheet is T% and the thickness is t μm.

[0031] <20> The resin sheet according to any one of <16> to <19>, wherein the surface roughness Ra of at least one surface of the resin sheet is 0.4 to 3.0 μm.

[0032] <21> The resin sheet according to any one of <16> to <20>, wherein the surface roughness Ra of the first surface of the resin sheet is 0.4 to 3.0 μm, and the surface roughness of the second surface is 0.1 to 2.5 μm smaller than the surface roughness of the first surface.

[0033] <22> The resin sheet according to any one of <16> to <21>, wherein the sheet surface 1m 2 The number of foreign particles with a size of 0.5 mm or more, obtained by averaging the lengths of the long sides and the short sides, was 0 to 10 when observed under a microscope.

[0034] <23> A multilayer body comprising the resin sheet according to any one of <16> to <22>.

[0035] <24> The multilayer body as described in <23>, which contains at least two resin sheets described in any one of <16> to <22>, and in the cross-sectional direction of the above-mentioned multilayer body, two of the above-mentioned resin sheets are located in symmetrical positions with respect to the center plane of the above-mentioned cross-section in a direction perpendicular to the thickness direction.

[0036] <25> The multilayer body according to <23> or <24>, wherein at least one of the intermediate layer sheets constituting the multilayer body is the resin sheet according to any one of <16> to <22>, and has at least one opening within the surface of the sheet.

[0037] <26> The multilayer body according to any one of <23> to <25>, wherein the multilayer body has a structure in which the resin sheet according to any one of <16> to <22>, a transparent resin sheet, and the resin sheet according to any one of <16> to <22> are stacked in this order.

[0038] <27> The multilayer body according to any one of <23> to <26>, wherein the surface roughness Ra of both surfaces of the multilayer body is 0.1 to 3.5 μm.

[0039] <28> The multilayer body according to any one of <23> to <27>, wherein the total thickness of the multilayer body is 0.2 to 2.0 mm.

[0040] <29> The multilayer body according to any one of <23> to <28>, wherein at least one layer of the multilayer body contains a laser color forming agent.

[0041] <30> The multilayer body according to any one of <23> to <29>, further comprising a layer containing a colorant that emits visible light when irradiated with ultraviolet rays or infrared rays.

[0042] <31> The multilayer body according to <30>, further comprising a layer containing a colorant that emits visible light having a wavelength different from that of the colorant that emits visible light when irradiated with ultraviolet rays or infrared rays.

[0043] <32> A card comprising the resin sheet according to any one of <16> to <22> or the multilayer body according to any one of <23> to <31>.

[0044] <33> The card according to <32>, which is a security card.

[0045] Effects of the Invention

[0046] The present invention can provide a resin composition capable of obtaining a thin resin sheet having excellent light shielding performance and excellent lamination performance, as well as a resin sheet, a multilayer body, and a card using the resin composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram showing an example of the layer structure of a conventional security card.

[0048] Figure 2 This is a schematic diagram showing an example of the layer structure of a security card (multi-layer body) having a transparent window.

[0049] Figure 3 This is a schematic diagram for explaining the layer structure of a security card (multi-layer body) having a transparent window.

[0050] Figure 4 It is a schematic diagram showing the size of the multilayer body having a transparent window (opening) produced in the example. DETAILED DESCRIPTION

[0051] A specific embodiment (hereinafter referred to as "this embodiment") will be described in detail below. Note that the following this embodiment is merely an example for explaining the present invention, and the present invention is not limited to this embodiment.

[0052] In addition, in this specification, "to" is used to mean that the numerical values ​​described before and after it are included as the lower limit and the upper limit.

[0053] In this specification, various physical property values ​​and characteristic values ​​are values ​​at 23°C unless otherwise specified.

[0054] In this specification, "sheet" and "multilayer body" refer to a thin and substantially flat formed body relative to its length and width, and also include "film". In addition, "sheet" in this specification can be a single layer or a multilayer, preferably a single layer.

[0055] In addition, in this specification, "mass parts" means the relative amount of a component, and "mass %" means the absolute amount of a component.

[0056] The resin composition of this embodiment is characterized by containing 25 to 79.5 parts by mass of a polycarbonate resin, 0.5 to 40 parts by mass of a polyester, and 20 to 50 parts by mass of titanium oxide. This composition can provide a thin resin sheet having excellent light shielding properties and excellent lamination properties.

[0057] In other words, by creating an extremely thin resin sheet from a resin composition with an increased titanium oxide content, a resin sheet with excellent obscuring properties and transparent window formability can be obtained. As a result, even when used in the white core layer of a security card with a transparent window, it can effectively conceal an IC chip or the like contained within the security card. Furthermore, in this embodiment, by adding a polyester, a resin composition with excellent lamination properties can be obtained.

[0058] Polycarbonate resin

[0059] The resin composition of this embodiment contains a polycarbonate resin. The polycarbonate resin serves as a matrix of the resin sheet.

[0060] The polycarbonate resin is not particularly limited as long as it is a resin containing a carbonate bond and an -[O-R-OCO]- structural unit (R is a hydrocarbon group (for example, an aliphatic group, an aromatic group, or a group containing both an aliphatic group and an aromatic group, and a group having a linear structure or a branched structure)) in the main chain of the molecule, and various polycarbonate resins can be used.

[0061] In this embodiment, aromatic polycarbonate resins are preferred, and bisphenol polycarbonate resins are more preferred. Bisphenol polycarbonate resins refer to polycarbonate resins in which 80 mol% or more, preferably 90 mol% or more, of the structural units constituting the polycarbonate resin are carbonate structural units derived from bisphenol (preferably bisphenol A) and / or its derivatives.

[0062] The bisphenol polycarbonate resin is preferably a bisphenol A polycarbonate resin.

[0063] The molecular weight of the polycarbonate resin is not particularly limited. Generally, the viscosity-average molecular weight, calculated from the solution viscosity measured at 25°C using dichloromethane as a solvent, is preferably 20,000 or greater. Furthermore, the viscosity-average molecular weight is preferably 35,000 or less, more preferably 32,000 or less, even more preferably 29,000 or less, further preferably 25,000 or less, and may be 23,000 or less. Using such a polycarbonate resin promotes uniform dispersion of the raw materials of the resin composition during melt extrusion, effectively suppressing the occurrence of white streaks. More specifically, by setting the viscosity-average molecular weight above the lower limit, the viscosity during melt mixing can be increased, tending to improve the uniform dispersion of the raw materials of the resin composition within the extruder, and tending to reduce the occurrence of foreign matter caused by poor mixing of the raw materials. Furthermore, by setting the viscosity-average molecular weight below the upper limit, moldability tends to be improved.

[0064] In the present embodiment, two or more polycarbonate resins having different viscosity average molecular weights may be mixed and used. In this case, a polycarbonate having a viscosity average molecular weight outside the above-described suitable range may be mixed.

[0065] The viscosity average molecular weight [Mv] is the intrinsic viscosity [η] (unit: dL / g) at 25°C, obtained using dichloromethane as the solvent and an Ubbelohde viscometer. From the Schnell viscosity formula, η = 1.23 × 10 －4 Mv 0.83 The intrinsic viscosity [η] refers to the specific viscosity [η] when measuring the concentration [C] (g / dL) of each solution. sp ], the value calculated by the following formula.

[0066]

[0067] In addition, details of the polycarbonate resin can be referred to paragraphs 0011 to 0020 of Japanese Patent Application Laid-Open No. 2012-144604 and paragraphs 0014 to 0035 of Japanese Patent Application Laid-Open No. 2019-002023 without departing from the gist of the present embodiment, and these contents are incorporated into the present specification.

[0068] The resin composition of the present embodiment preferably contains the polycarbonate resin in a ratio of 25 to 79.5% by mass in the resin composition, and more preferably contains the polycarbonate resin in a ratio of 40 to 75% by mass.

[0069] The resin composition of the present embodiment may contain only one polycarbonate resin or two or more polycarbonate resins. When containing two or more polycarbonate resins, the total amount is preferably within the above range.

[0070] <Polyester>

[0071] The resin composition of the present embodiment may contain polyester. The resin composition of the present embodiment can improve the lamination properties of the resin sheet by containing polyester.

[0072] The type of polyester is not particularly limited, and may be an aliphatic polyester or an aromatic polyester containing an aromatic ring.

[0073] In this embodiment, the type of aliphatic polyester is not particularly limited, but it preferably contains structural units derived from lactone compounds. Such aliphatic polyesters have extremely low glass transition points and excellent compatibility with polycarbonate resins. Therefore, even a small amount of addition can achieve good lamination properties and effectively suppress degradation of the chemical and mechanical properties of the polycarbonate resin. In this embodiment, the proportion of structural units derived from lactone compounds in the aliphatic polyester is preferably 70 mol% or greater, more preferably 80 mol% or greater, even more preferably 90 mol% or greater, further preferably 95 mol% or greater, and even more preferably 99 mol% or greater, based on the total structural units excluding terminal groups.

[0074] Examples of the lactone compound include ε-caprolactone, β-propiolactone, and δ-valerolactone, with ε-caprolactone being preferred. Furthermore, a copolymer of two or more of these lactone compounds may be used.

[0075] The aliphatic polyester used in the present embodiment is preferably polycaprolactone.

[0076] The weight-average molecular weight of the aliphatic polyester compound used in this embodiment is preferably 5,000 to 90,000. It is more preferably 7,000 to 60,000, even more preferably 8,000 to 40,000, and even more preferably 8,000 to 12,000. By setting the weight-average molecular weight above the lower limit, film formability tends to be further improved. Furthermore, by setting the weight-average molecular weight below the upper limit, lamination properties tend to be further improved. The weight-average molecular weight is a polystyrene-equivalent value measured by GPC (gel permeation chromatography).

[0077] When the resin composition of the present embodiment contains an aliphatic polyester, it is preferably contained in a ratio of 0.5% by mass or more in the resin composition, more preferably contained in a ratio of 1.0% by mass or more, and even more preferably contained in a ratio of 2% by mass or more. The resin composition of the present embodiment preferably contains the aliphatic polyester in a ratio of 9% by mass or less in the resin composition, more preferably contained in a ratio of 8% by mass or less, even more preferably contained in a ratio of 7% by mass or less, and may also be 5% by mass or less, or 3% by mass or less. By setting it above the lower limit, there is a tendency for the laminating property to be improved. By setting it below the upper limit, there is a tendency for the moldability during the resin sheet molding to be further improved.

[0078] In the present embodiment, the type of aromatic polyester is not particularly limited, and is preferably a polyester (PCTG) containing structural units derived from terephthalic acid, structural units derived from ethylene glycol, and structural units derived from cyclohexanedimethanol. The above-mentioned polyester (PCTG) is a thermoplastic resin with excellent compatibility with polycarbonate resin, and the reduction in the durability of the polycarbonate resin due to addition is less. By using this polyester, a resin composition having excellent durability in addition to lamination properties can be obtained. The above-mentioned polyester (PCTG) is a polyester obtained by replacing a part of the ethylene glycol in the raw material monomer of polyethylene terephthalate with cyclohexanedimethanol. In the present embodiment, when the total of the structural units derived from ethylene glycol and the structural units derived from cyclohexanedimethanol is 100 mol%, the proportion of the structural units derived from cyclohexanedimethanol is preferably 50 mol% or more and less than 100 mol%, more preferably 60 to 90 mol%. Without departing from the scope of the present embodiment, PCTG may contain raw material monomers other than the structural units derived from terephthalic acid, the structural units derived from ethylene glycol, and the structural units derived from cyclohexanedimethanol. In the present embodiment, the total of the structural units derived from terephthalic acid, the structural units derived from ethylene glycol, and the structural units derived from cyclohexanedimethanol in PCTG preferably accounts for 90 mol% or more of the total structural units excluding the terminal groups, more preferably 95 mol% or more, and even more preferably 99 mol% or more.

[0079] The intrinsic viscosity (IV value measured by a capillary viscometer: ISO 1628-1 1998) of the aromatic polyester compound used in this embodiment is preferably 0.5 to 1.0, more preferably 0.6 to 0.9, and particularly preferably 0.7 to 0.8. Within the above range, film formability tends to be further improved.

[0080] When the resin composition of the present embodiment contains an aromatic polyester, it is preferably contained in a ratio of 10% by mass or more in the resin composition, more preferably in a ratio of 15% by mass or more, and even more preferably in a ratio of 20% by mass or more. The resin composition of the present embodiment preferably contains the aromatic polyester in a ratio of 40% by mass or less in the resin composition, more preferably in a ratio of 35% by mass or less, and even more preferably in a ratio of 30% by mass or less. By setting the value above the lower limit, lamination properties can be improved. By setting the value below the upper limit, there is a tendency for the formability during sheet molding to be further improved.

[0081] Titanium oxide

[0082] The resin composition of this embodiment contains titanium oxide. By containing titanium oxide, a resin sheet having excellent shielding properties can be provided.

[0083] As the titanium oxide used in the present embodiment, a wide range of titanium oxides that can be incorporated into a resin sheet can be adopted.

[0084] In the present embodiment, titanium oxide is preferably rutile titanium oxide. By using rutile titanium oxide, the decomposition of polycarbonate resin can be suppressed. In addition, the surface of titanium oxide is preferably treated with a surface treatment agent. That is, it is preferred that a layer (especially an organic layer) formed by a surface treatment agent is provided on the surface of the titanium oxide. By setting it to this structure, titanium oxide is easily dispersed in the polycarbonate resin, and a resin sheet with a more excellent appearance can be obtained. Moreover, the decomposition of the polycarbonate resin during melt extrusion can be effectively suppressed. The surface treatment agent can exemplify a polymer, preferably a siloxane compound, particularly preferably hydrogen methyl siloxane, dimethyl siloxane, etc. The surface treatment agent can be physically adsorbed on the titanium oxide surface or chemically bonded.

[0085] Furthermore, titanium oxide may have an oxide layer between the titanium oxide and the layer formed by the surface treatment agent. The oxide layer helps maintain the granular shape and inhibits resin decomposition. Examples of the oxide layer include aluminum oxide layers, silicon dioxide layers, and zirconium oxide layers. The oxide layer may be a single layer or may have multiple layers.

[0086] The titanium oxide used in this embodiment is preferably in a granular form.

[0087] The average primary particle size of titanium oxide is preferably 100 nm or more, more preferably 150 nm or more, even more preferably 180 nm or more, and may be 220 nm or more. Furthermore, the average primary particle size of titanium oxide is preferably 500 nm or less, more preferably 400 nm or less, even more preferably 350 nm or less, and may be 300 nm or less, or 260 nm or less. By setting the average primary particle size of titanium oxide within this range, there is a tendency for shielding performance to be further improved.

[0088] The average primary particle size of titanium oxide is measured as described in Examples below.

[0089] The resin composition of this embodiment preferably contains titanium oxide at a ratio of 20 to 50% by mass, more preferably 25 to 45% by mass, and even more preferably 25 to 35% by mass. By setting the ratio above the lower limit, the shielding properties of the resulting resin sheet tend to be further improved. By setting the ratio below the upper limit, the generation of white streaks in the resulting resin sheet can be effectively suppressed, and film formability tends to be further improved.

[0090] <Blending ratio of polycarbonate resin, polyester, and titanium oxide>

[0091] The resin composition of this embodiment contains 25 to 79.5 parts by mass of a polycarbonate resin, 0.5 to 40 parts by mass of a polyester (the content of aliphatic polyester is preferably 0.5 to 9 parts by mass, and the content of aromatic polyester is preferably 10 to 40 parts by mass), and 20 to 50 parts by mass (preferably 22 parts by mass or more, more preferably 25 parts by mass or more, and preferably 40 parts by mass or less, more preferably 38 parts by mass or less, and even more preferably 35 parts by mass or less) of titanium oxide. Furthermore, an antioxidant, other colorants, an antistatic agent, and other ingredients may also be included. By setting such a blending ratio, a resin sheet with excellent shielding properties and lamination properties can be obtained.

[0092] The first embodiment of the resin composition of this embodiment has a blending ratio of 41 to 79.5 parts by mass (preferably 58 to 73 parts by mass) of a polycarbonate resin, 20 to 50 parts by mass (preferably 25 to 35 parts by mass) of titanium oxide, and 0.5 to 9 parts by mass (preferably 1 part by mass or greater, more preferably 1.5 parts by mass or greater, even more preferably 2.0 parts by mass or greater, and preferably 9 parts by mass or less, more preferably 7 parts by mass or less, even more preferably 5 parts by mass or less, or 3 parts by mass or less) of a polyester (preferably an aliphatic polyester). Resin sheets obtained from a resin composition having such a blending ratio are suitable for use in reflective sheets, card products, and the like.

[0093] A second embodiment of the blending ratio of the resin composition of this embodiment is as follows: it contains 25 to 70 parts by mass (preferably 35 to 60 parts by mass) of polycarbonate resin, 20 to 50 parts by mass (preferably 25 to 35 parts by mass) of titanium oxide, and 10 to 40 parts by mass (preferably 20 parts by mass or more and preferably 30 parts by mass or less) of polyester (preferably aromatic polyester). The resin sheet obtained from the resin composition with such a blending method is suitable for use in the white core layer of a card with a transparent window. In particular, in the resin composition of this embodiment, due to the high dispersibility of titanium oxide, even an extremely thin resin sheet can achieve sufficient shielding properties, which is preferred.

[0094] The resin composition of the present embodiment preferably satisfies the above ratio when the total of the polycarbonate resin, titanium oxide, and polyester is 100 parts by mass.

[0095] In the resin composition of this embodiment, the total amount of polycarbonate resin, polyester, and titanium oxide preferably accounts for 90% by mass or more of the resin composition, more preferably 95% by mass or more, and may account for 98% by mass or more. The upper limit is 100% by mass or less.

[0096] In the resin composition of this embodiment, the difference between the polycarbonate resin content and the titanium oxide content (polycarbonate resin content - titanium oxide content) is preferably 10 parts by mass or more and preferably 59.5 parts by mass or less. Within this range, the film moldability tends to be further improved.

[0097] And, in the resin combination of present embodiment, the content of polycarbonate resin is preferably more than the content of polyester, preferably more than 1 mass part. In addition, the upper limit value of the difference between the content of polycarbonate resin and the content of polyester is below 76 mass parts. By being within such a range, there is a tendency to maintain the physical properties and light shielding performance of polycarbonate higher and obtain a resin combination with thin and more excellent laminating performance.

[0098] In the resin composition of the present embodiment, only one type of each of the polycarbonate resin, polyester, and titanium oxide may be used, or two or more types may be used. When two or more types are used, the total amount is preferably within the above range.

[0099] <Other colorants>

[0100] The resin composition of this embodiment may also contain a colorant other than titanium oxide. By adding other colorants, the resin composition can be given a slight color, which tends to improve the appearance (design) of the resin sheet. It can also further improve light shielding performance.

[0101] Examples of the other colorants include inorganic pigments, organic pigments, and organic dyes.

[0102] Examples of the inorganic pigments include sulfide pigments such as carbon black, cadmium red, and cadmium yellow; silicate pigments such as ultramarine; oxide pigments such as zinc white, iron red, chromium oxide, iron black, titanium yellow, zinc-iron brown, titanium cobalt green, cobalt green, cobalt blue, copper-chromium black, and copper-iron black; chromate pigments such as chrome yellow and molybdenum orange; and ferrocyanide pigments such as Prussian blue.

[0103] Examples of organic pigments and organic dyes include phthalocyanine dyes or pigments such as copper phthalocyanine blue and copper phthalocyanine green; azo dyes or pigments such as nickel azo yellow; condensed polycyclic dyes or pigments such as thioindigo, pyrene, perylene, quinacridone, dioxazine, isoindolinone, and quinophthalone; and anthraquinone, heterocyclic, and methyl-based dyes or pigments.

[0104] Specific examples of the aforementioned other colorants include those with a maximum absorption in the wavelength range of 450 to 650 nm. By incorporating a colorant with a maximum absorption in the wavelength range of 450 to 650 nm that effectively absorbs light near the wavelength of 550 nm, which is the peak wavelength for human perception, the shielding properties of the resin sheet can be improved.

[0105] Another example of an embodiment in which the other colorant is a dye is mentioned. Examples of the dye include colorants having maximum absorption in the wavelength range of 450 to 650 nm.

[0106] Furthermore, as a specific example of the other colorant, the carbon black mentioned above can also be mentioned. By adding carbon black, the light shielding performance of the resin sheet can be further improved.

[0107] When the resin composition of this embodiment contains other colorants, their content in the resin composition is preferably 5 mass ppm or more, more preferably 7 mass ppm or more, even more preferably 10 mass ppm or more, further preferably 15 mass ppm or more, and may be 20 mass ppm or more. The upper limit of the content of these other colorants is preferably 150 mass ppm or less, more preferably 120 mass ppm or less, even more preferably 100 mass ppm or less, and even more preferably 80 mass ppm or less. Within this range, the appearance of the resulting resin sheet tends to be further improved, and the light-shielding performance tends to be further enhanced.

[0108] The resin composition of the present embodiment may contain only one other colorant or two or more. When containing two or more, the total amount is preferably within the above range.

[0109] <Various additives>

[0110] The resin composition of the present embodiment may further contain various additives.

[0111] The resin composition of the present embodiment preferably contains an antioxidant. The resin composition of the present embodiment preferably contains an antioxidant in a ratio of 0.01 to 0.2% by mass in the above-mentioned resin composition, and more preferably contains it in a ratio of 0.02 to 0.1% by mass. By containing an antioxidant, thermal decomposition during processing can be suppressed, and there is a tendency to prevent color change or prevent melt viscosity from decreasing. As an antioxidant, its type is not particularly limited, and phosphites and phosphonites can be exemplified, preferably phosphites. The antioxidant can refer to the records of paragraphs 0059 to 0061 of Japanese Patent Application Publication No. 2018-090677, and these contents are introduced into this specification.

[0112] The resin composition of this embodiment also preferably contains an antistatic agent. The resin composition of this embodiment preferably contains an antistatic agent in a ratio of 0.01 to 1.5% by mass of the resin composition, and more preferably 0.1 to 0.8% by mass. Using such an antistatic agent in this range tends to further improve dust resistance and transportability.

[0113] The antistatic agent is not particularly limited in type, and examples thereof include phosphonium salt compounds. Specific examples of the antistatic agent include phosphonium salt compounds described in Japanese Patent Application Laid-Open No. 2016-108424 and International Publication No. 2020 / 122055, the contents of which are incorporated herein.

[0114] The resin composition of the present embodiment may also contain other ingredients other than those mentioned above. Other ingredients include at least one additive selected from a heat stabilizer, a flame retardant, a flame retardant auxiliary, an ultraviolet absorber, and a release agent. In addition, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiviral agents, etc. may also be added without significantly damaging the desired physical properties.

[0115] The content of the other components in the resin composition of the present embodiment, if contained, is, for example, 0.001 mass % or more, and for example, 5.0 mass % or less, preferably 3.0 mass % or less, and more preferably 1.0 mass % or less, based on the mass of the resin composition.

[0116] <Physical Properties of Resin Composition>

[0117] The glass transition temperature of the resin composition of this embodiment, as measured by the method specified in JIS K7121:1987 (DSC), is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, and may be 125°C or higher. By exceeding this lower limit, the durability of the resin composition tends to be further improved. Furthermore, the glass transition temperature is preferably 155°C or lower, more preferably 150°C or lower, even more preferably 148°C or lower, further preferably 145°C or lower, even more preferably 140°C or lower, and even more preferably 135°C or lower. By exceeding this upper limit, moldability at lower temperatures can be achieved.

[0118] The resin composition of the present embodiment preferably has a melt volume flow rate (MVR) value of 2.0 cm2 as measured at 300° C. and a load of 1.2 kgf in accordance with JIS K7210. 3 / 10min or more, more preferably 3.0cm 3 / 10min or more, more preferably 5.0cm 3 / 10min or more, more preferably 8.0cm 3 / 10min or more, more preferably 10.0cm 3 / 10min or more, more preferably 12.0cm 3By exceeding the above lower limit, the uniform dispersion of the raw materials of the resin composition in the extruder can be improved, and there is a tendency to further reduce foreign matter caused by poor mixing of the raw materials. In addition, the upper limit of the above MVR is preferably 50.0 cm 3 / 10min or less, more preferably 40.0cm 3 / 10min or less, more preferably 35.0cm 3 / 10min or less, more preferably 30.0cm 3 / 10min or less, more preferably 25.0cm 3 / 10min or less, can also be 19.0cm 3 / 10min or less, 16.0cm 3 When the above upper limit is not more than the above upper limit, the film forming efficiency tends to be further improved.

[0119] The glass transition temperature and melt volume flow rate were measured according to the description in the examples described below.

[0120] <Physical Properties of Resin Sheets>

[0121] The resin sheet of this embodiment is a resin sheet formed from a resin composition. The resin sheet of this embodiment is preferably used as a constituent layer of a card. That is, the resin composition of this embodiment is suitable as a resin composition for cards.

[0122] In the resin sheet of this embodiment, the lower limit of its thickness is preferably 20 μm or more, more preferably 25 μm or more. Furthermore, the upper limit of the thickness is preferably 200 μm or less, more preferably 180 μm or less, even more preferably 150 μm or less, further preferably 120 μm or less, further preferably 110 μm or less, even more preferably 100 μm or less, and even more preferably 80 μm or less. It may also be 70 μm or less or 60 μm or less. By exceeding the lower limit, there is a tendency for the light shielding performance of the resin sheet to be further improved. By exceeding the upper limit, the formability of the multilayer sheet having a transparent window structure can be further improved.

[0123] The resin sheet of this embodiment preferably has less foreign matter. Specifically, in the sheet surface 1m 2The number of foreign matters with a size of 0.5 mm or more, obtained by averaging the lengths of the long sides and the short sides observed under a microscope, is preferably 0 to 10, more preferably 0 to 5, and even more preferably 0 to 3. In this embodiment, in order to improve the light shielding property of the resin sheet, it is necessary to contain titanium oxide at a high concentration. On the other hand, as described above, when titanium oxide is contained at a high concentration and an extremely thin resin sheet is made, sometimes there will be an area on the resin sheet with low shielding performance that is elongated along the sheet winding direction, which appears to be locally bright and strip-shaped, resulting in poor appearance called "white stripes". In this embodiment, by limiting the number of foreign matters with a diameter of 0.5 mm or more among the foreign matters contained in the resin sheet to below the above range, the occurrence of white stripes can be more effectively suppressed.

[0124] Methods for reducing the number of foreign matter particles with a particle size of 0.5 mm or greater include using a polycarbonate resin with a viscosity-average molecular weight of 20,000 to 35,000 (particularly 25,000 or less, and more preferably 23,000 or less). Other methods include pulverizing or surface-treating titanium oxide. Furthermore, it is preferable to keep the extrusion conditions (melt temperature, screw configuration, screw speed, and discharge rate) during melt kneading within appropriate ranges.

[0125] The number of foreign matter was measured according to the method described in the examples below.

[0126] The resin sheet of this embodiment preferably has excellent light-shielding properties. Specifically, the total light transmittance T is preferably 20% or less, preferably 15% or less, more preferably 12% or less, and even more preferably 10% or less. The lower limit of the total light transmittance is preferably 0%, but may be 1% or greater. The total light transmittance T is measured according to the method described in the Examples below.

[0127] The resin sheet of this embodiment preferably has a total light transmittance of T% and a thickness of tμm, T×t, of 200 or greater, more preferably 210 or greater, even more preferably 220 or greater, further preferably 230 or greater, and even more preferably 240 or greater. By exceeding this lower limit, light shielding properties and moldability tend to be well-balanced. The upper limit is preferably 750 or less, more preferably 740 or less, further preferably 730 or less, further preferably 720 or less, and even more preferably 710 or less. By exceeding this upper limit, light shielding properties and moldability tend to be well-balanced.

[0128] In the resin composition of the present embodiment, the surface roughness Ra of the face of at least one side is preferably more than 0.4 μm, more preferably more than 0.5 μm, more preferably more than 0.7 μm, and can also be more than 0.9 μm, more than 1.1 μm. By being above the above lower limit, there is a tendency that the handling and lamination of the sheet material become more excellent. In addition, the upper limit of the surface roughness Ra of the face of at least one side is preferably less than 3.0 μm, more preferably less than 2.5 μm, and can also be less than 2.0 μm, less than 1.8 μm, or less than 1.5 μm. By being below the above upper limit, there is a tendency that printing clarity further improves.

[0129] In this embodiment, the surface roughness Ra of one side of the resin sheet is preferably within the above range (0.4 μm to 3.0 μm), and the surface roughness of the other side is preferably 0.4 μm to 1.9 μm. This configuration allows for more effective transportability and lamination of the resin sheet.

[0130] In addition, the resin sheet of this embodiment preferably has a surface roughness Ra of the first surface within the above range (0.4 μm to 3.0 μm), and a surface roughness of the second surface that is 0.1 to 2.5 μm (preferably 0.1 to 0.5 μm, more preferably 0.15 to 0.35 μm) less than the surface roughness of the first surface. By having such a structure, there is a tendency for the sheet's handling and lamination properties to be further improved.

[0131] The surface roughness Ra is measured according to the description in the examples described below.

[0132] <Method for producing resin sheet>

[0133] The manufacture method of the resin sheet of the present embodiment can adopt the known method that resin combination is processed into sheet.Specifically can illustrate extrusion molding, solution casting molding, preferably extrusion molding.As the example of extrusion molding, can cite the following method, the pellets, thin slice or powder of the resin combination of the present embodiment are put into extruder and are melted, rubbed, afterwards extruded from T die etc., the obtained semi-molten sheet is pressed with roller clamp, while cooling, solidifying, thereby forming sheet.

[0134] <Multilayered body>

[0135] The multilayer body of this embodiment comprises the resin sheet of this embodiment. It is particularly preferred that at least one of the intermediate layer sheets of the multilayer body of this embodiment be the resin sheet of this embodiment, and that the sheet have at least one opening within its surface. Such an opening can be used, for example, as a transparent window in a security card. Furthermore, because the resin sheet of this embodiment is extremely thin and has excellent light-shielding properties, even a multilayer body having a transparent window can achieve sufficient light-shielding properties.

[0136] The multilayer body of this embodiment preferably includes at least two resin sheets of this embodiment, and in the cross-sectional direction of the multilayer body, the two resin sheets are located at symmetrical positions with respect to the center plane of the cross section in the direction perpendicular to the thickness direction. Particularly preferably, in the thickness direction of the cross-sectional thickness of the multilayer body of this embodiment, in a mode in which the resin sheet of this embodiment does not exist, the two resin sheets are located at symmetrical positions with respect to the center plane of the cross section in the direction perpendicular to the thickness direction. An example of such a multilayer body is Figure 3 The composition shown. Figure 3 (A) is a view when viewed from the cross-sectional direction (thickness direction) of the multilayer body, and (B) is a view when viewed from the surface (sheet surface of the resin sheet) of the multilayer body. Figure 3 In FIG. 1 , 30 represents a multilayer body, 31 represents a cover layer (transparent resin sheet), 32 represents a white core layer (resin sheet of this embodiment), 33 represents a transparent window (opening), and 34 represents a transparent core layer (transparent resin sheet). Figure 3 The line AA indicated by a dotted line in (A) corresponds to the position of the center plane of the cross section of the multilayer body in a direction perpendicular to the thickness direction. Figure 3 The multilayer body shown has a transparent window (opening) 33 in a region where the white core layer (resin sheet of this embodiment) does not exist in the cross-sectional direction of the multilayer body. Moreover, the white core layer (resin sheet of this embodiment) 32 and the transparent window (opening) 33 are oriented with the center plane ( Figure 3 The two components are located symmetrically with respect to a surface through which a dotted line AA passes.

[0137] In addition, Figure 3 In the multilayer body shown, Figure 3 When the multilayer body shown in (A) is observed in cross-section, only the white core layer 32 appears white. When the multilayer body shown in (B) is observed in the surface direction, the entire body except the transparent window 33 appears white due to the white core layer 32.

[0138] Figure 3 In the multilayer body shown, the transparent window 33 can be produced by laminating the cover layer 31, the white core layer 32, the transparent core layer 34, the white core layer 32, and the cover layer 31 and then hot pressing them. In other words, the transparent window is formed when a portion of the transparent resin sheet enters (fills) the portion (opening) between the cover layer 31 and the transparent core layer 34 during hot pressing. Of course, the multilayer body of this embodiment can also be produced by other methods without departing from the scope of the present embodiment.

[0139] On the other hand, the transparent resin sheet constituting the cover layer 31 and the transparent core layer 34 is formed from a composition containing a thermoplastic resin, for example, a resin composition obtained by removing titanium oxide from the resin composition used to form the resin composition of this embodiment. Therefore, an example of the transparent resin sheet is a polycarbonate resin sheet.

[0140] in addition, Figure 3 The multilayer body shown has a structure in which the resin sheet (white core layer) 32 of this embodiment, the transparent core layer (transparent resin sheet) 34, and the resin sheet (white core layer) 32 of this embodiment are stacked in sequence (preferably continuously), but forms other than this are not excluded.

[0141] Furthermore, the multilayer body of this embodiment is not limited to Figure 3 The layer structure shown. Therefore, Figure 3 The multilayer body shown can of course also contain other layers without departing from the spirit of the present invention.

[0142] The multilayer body of this embodiment preferably contains a laser coloring agent in at least one layer. The layer containing the laser coloring agent is preferably used as a laser marking layer. Such a layer containing the laser coloring agent is preferably provided on the outside of the resin sheet of this embodiment. That is, it can be provided on the outside of the resin sheet. Figure 3 The white core layer 32 is positioned closer to the surface. The laser coloring agent is preferably a black coloring agent, more preferably carbon black. Alternatively, a metal oxide laser marking agent may be used. Details of the laser marking layer can be found in Japanese Patent Application Laid-Open No. 2020-75487, which is incorporated herein by reference.

[0143] Alternatively, the multilayer body of this embodiment may include a layer containing a colorant that emits visible light when irradiated with ultraviolet or infrared light. By providing such a layer, the multilayer body can be used as a security card capable of verifying authenticity. Specifically, a card that emits light when irradiated with a predetermined light source can be identified as authentic.

[0144] In this embodiment, a configuration may also be provided in which a layer containing a colorant that, upon exposure to ultraviolet or infrared light, emits visible light of a wavelength different from that of the colorant emitting the aforementioned visible light can be included. In this case, the layer containing the colorant emitting the aforementioned visible light and the layer containing the colorant emitting visible light of a wavelength different from that of the colorant emitting the aforementioned visible light can be separate layers or the same layer. In other words, this embodiment also includes a configuration in which two or more colorants emitting visible light of mutually different wavelengths are included in the same layer.

[0145] In the multilayer body of this embodiment, the layer containing the colorant emitting visible light is preferably provided on the outer side of the resin sheet of this embodiment. Figure 3The white core layer 32 is closer to the surface side.

[0146] Regarding the layer containing a colorant that emits visible light, reference can be made to the description of Japanese Patent Application Laid-Open No. 2020-75487, the contents of which are incorporated herein.

[0147] The multilayer body of this embodiment preferably has a surface roughness Ra of 0.1 μm or greater, more preferably 0.5 μm or greater. By exceeding this lower limit, the handling and laminating properties of the multilayer body tend to be further improved. Furthermore, the upper limits of the surface roughness Ra of each of the two surfaces of the multilayer body are preferably 3.5 μm or less, more preferably 3.2 μm or less. By exceeding this upper limit, printing clarity tends to be further improved.

[0148] The thickness of the multilayer body of this embodiment can be appropriately determined depending on the intended use, with the total thickness preferably being 0.2 mm or greater, and more preferably 0.3 mm or greater. By exceeding this lower limit, it is easier to incorporate IC chips and antennas. Furthermore, the upper limit of the total thickness is preferably 2.0 mm or less, and more preferably 1.0 mm or less. By exceeding this upper limit, card storage capacity tends to be further improved.

[0149] In the method for manufacturing the multilayer body of the present embodiment, in addition to the above-mentioned hot pressing of each constituent layer, adhesives etc. can also be utilized to improve the adhesion between each layer without departing from the scope of the present embodiment. In addition, each layer can also be made into a sheet by coextrusion.

[0150] <Application>

[0151] The following describes the uses of the resin sheet and the multilayer body of the present embodiment. The resin sheet and / or the multilayer body of the present embodiment is preferably used for a card containing the same.

[0152] The card is preferably a security card. Examples of the security card in this embodiment include an identity card (ID card), a passport, a driver's license, a bank card, a credit card, a social security card, and other identity cards.

[0153] In the present embodiment, the description in paragraphs 0048 to 0059 of Japanese Patent Application Laid-Open No. 2016-108424 and the description in paragraphs 0075 to 0088 of Japanese Patent Application Laid-Open No. 2015-168728 may be referred to without departing from the gist of the present invention, and the contents may be incorporated into the present specification.

[0154] Example

[0155] The present invention is further described in detail below with reference to the following examples. The materials, usage amounts, ratios, treatment contents, and treatment operations shown in the following examples can be appropriately modified without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0156] When the measuring instruments used in the examples are difficult to obtain due to discontinuation of sales or the like, measurements can be performed using other instruments having equivalent performance.

[0157] 1. Raw Materials: Polycarbonate Resin

[0158] S-3000F: bisphenol A polycarbonate resin, IUPILON (registered trademark), viscosity average molecular weight Mv 21,000, manufactured by Mitsubishi Engineering-Plastics Corporation.

[0159] Titanium oxide

[0160] PFC317: rutile titanium oxide particles whose surfaces were sequentially treated with silica, alumina, and siloxane, manufactured by Ishihara Sangyo Co., Ltd., with an average primary particle size of 0.24 μm (240 nm).

[0161] PFC310: rutile titanium oxide particles whose surfaces were sequentially treated with silica, alumina, and siloxane, manufactured by Ishihara Sangyo Co., Ltd., with an average primary particle size of 0.20 μm (200 nm).

[0162] <<Method for measuring average primary particle size>>

[0163] Titanium oxide was sputtered using a sputtering device. The target material was Pt, and the coating time was 30 seconds. The titanium oxide that had undergone the above sputtering treatment was observed and photographed using a field emission scanning electron microscope. The observation was carried out under the conditions of accelerating voltage: 5kV and observation magnification: 35,000 times. Using image analysis software, the sum of the major and minor diameters of the titanium oxide was measured from the obtained image, and the value obtained by dividing their sum by 2 was used as the particle size. The particle size was measured for 50 or more particles, and the average value was calculated.

[0164] The measurement was performed by three experts in the same manner, and the average value thereof was determined as the average primary particle size.

[0165] The sputtering apparatus used was E-1030 manufactured by Hitachi High-Technologies Corporation. The field emission scanning electron microscope used was FE-SEM (SU8220, manufactured by Hitachi High-Technologies Corporation). The image analysis software used was WinROOF 2013 (manufactured by Mitani Shoji Co., Ltd.).

[0166] <Polyester>

[0167] H1P: polycaprolactone (PCL), PLACCEL (registered trademark) manufactured by Daicel Corporation, weight average molecular weight: 10,000.

[0168] J2003: Polyester composed of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol (PCTG), SK Chemicals, intrinsic viscosity 0.75.

[0169] <Antioxidants>

[0170] AS2112: manufactured by ADEKA Corporation, tris(2,4-di-tert-butylphenyl) phosphite.

[0171] S-9228PC: manufactured by Dover Chemical Co., Ltd., Doverphos S-9228PC, bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0172] Antistatic Agents

[0173] Trihexyltetradecylphosphonium bis(trifluoromethanesulfonyl)amide: manufactured by MERCK, CAS No. 460092-03-9.

[0174] <Other colorants>

[0175] Carbon black M280: manufactured by CABOT, MONARCH280.

[0176] Dye 1: Macrolex Blue RR, a colorant having a maximum absorption in the wavelength range of 450 to 650 nm.

[0177] Dye 2: Macrolex Violet 3R, a colorant having a maximum absorption in the wavelength range of 450 to 650 nm.

[0178] 2. Examples 1 to 17 and Comparative Examples 1 to 3

[0179] <Manufacturing of resin pellets>

[0180] The components were blended using a drum so as to have the compositions shown in Tables 3 to 6 below (the contents in each table are expressed in parts by mass), fed from the root of a twin-screw extruder (manufactured by Nippon Steel Works, Ltd., TEX30α), and melt-kneaded at a barrel temperature of 240°C to produce pellets of the embodiments and comparative examples.

[0181] <Melt Volume Flow Rate (MVR) of Resin Composition>

[0182] The melt volume flow rate is measured in accordance with JIS K7210.

[0183] Specifically, the melt volume flow rate (unit: cm) was measured based on the amount of resin extruded per 10 minutes from a standard die provided at the bottom of the cylinder under a load of 1.2 kgf at 300°C. 3 / 10min).

[0184] <Glass transition temperature of resin composition>

[0185] The glass transition temperature is measured by the method specified in JIS K7121:1987 (DSC).

[0186] Specifically, using a differential scanning calorimeter under a nitrogen atmosphere, approximately 10 mg of a sample was heated from 30°C to 260°C at a heating rate of 20°C / minute. After maintaining the temperature for 5 minutes, the sample was cooled to 30°C at a rate of 30°C / minute. The sample was maintained at 30°C for 10 minutes, and then the temperature was increased to 260°C at a rate of 10°C / minute. The glass transition temperature (unit: °C) was determined based on the extrapolated glass transition onset temperature calculated from the DSC curve obtained during the second heating step.

[0187] As the differential scanning calorimeter, a differential scanning calorimeter EXSTARDSC7020 manufactured by Hitachi High-Technologies Corporation was used.

[0188] <Manufacturing of resin sheets>

[0189] Using the obtained pellets, a resin sheet was produced by the following method.

[0190] A T-die melt film forming extruder, comprised of a twin-screw extruder with a barrel diameter of 32 mm and a screw L / D (length / diameter) ratio of 31.5, was used to form a resin sheet with a width of 300 mm from the pellets at a rate of 20 kg / h and a screw speed of 200 rpm. The barrel and T-die temperatures were set at 240°C. The extruded molten sheet was sandwiched between a first cooling roll made of silicone rubber with a diameter of 250 mm and a ten-point average roughness Rzjis (JIS B0601:2013) of 21 μm and a second cooling roll made of metal with a diameter of 250 mm and an embossed ten-point average roughness Rzjis (JIS B0601:2013) of 18 μm. The embossed sheet was then passed through a third cooling roll made of metal with a mirror finish and taken up by a take-up roll, thereby forming a resin sheet having the thickness (average thickness) shown in Tables 3 to 6. At this time, the temperature of the first cooling roller was set to 50°C, the temperature of the second cooling roller was set to 100°C, and the temperature of the third cooling roller was set to 100°C.

[0191] <Manufacturing of laminating sheets>

[0192] A laminating sheet having an average thickness of 200 μm was prepared by the same method as that for producing the above-mentioned resin sheet using polycarbonate resin pellets E-2000 manufactured by Mitsubishi Engineering-Plastics Corporation.

[0193] Next, the surface of the obtained laminating sheet facing the embossed metal second cooling roll having a diameter of 250 mm and a ten-point average roughness Rzjis (JIS B0601:2013) of 18 μm was designated as surface A.

[0194] <Number of foreign matter>

[0195] The size of the cut sheet is 1m 2 A resin sheet was irradiated with S-Light from a distance of 60 cm perpendicular to the sheet surface. The surface opposite the irradiated surface was visually inspected. The length of foreign particles was measured using a microscope, and the number of foreign particles 0.5 mm or larger, calculated by averaging the lengths of the long and short sides, was determined. Five experts evaluated the results, and the average value (rounded to the nearest decimal point) was calculated.

[0196] S-Light irradiation was performed using equipment manufactured by Nippon Technology Center Co., Ltd. The microscope used was ECLIPSE LV100ND manufactured by Casio Corporation.

[0197] Surface roughness of resin sheet (Ra)

[0198] The surface roughness of the obtained resin sheet was measured at three random locations on the surface according to ISO 4287:1997 (measurement conditions: λc 0.8, λs 2.5), and the surface roughness (Ra) was calculated by taking the average of the three locations. The unit is μm.

[0199] The measurement was performed using a small surface roughness measuring machine SURFTEST SJ-210 manufactured by Mitutoyo Corporation.

[0200] <Shielding performance>

[0201] <<Measurement of total light transmittance>>

[0202] The total light transmittance was measured in accordance with ISO-13468-1 (measurement conditions: D65 light source, 10° field of view).

[0203] The haze meter HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd. was used for the measurement.

[0204] The unit of total light transmittance is %.

[0205] <<T×t>>

[0206] The product (T×t) of the total light transmittance (T) (unit: %) and the thickness (t) of the resin sheet (unit: μm) is calculated. Adjusting this value within the range of 200 to 750 will yield a multilayer body that achieves both good formability of the transparent window structure and good light shielding performance.

[0207] Transparent window size change rate

[0208] like Figure 4 The resin sheets obtained in each of the Examples and Comparative Examples were punched out to produce sheets having rectangular openings measuring 25 mm wide by 15 mm long. Laminating sheets cut into 150 mm by 110 mm rectangular shapes were laminated on both sides of the sheets, with surface A contacting the resin sheets. Lamination was performed under the conditions shown in Table 1.

[0209] For lamination, a tabletop card laminator OLA6E manufactured by OASYS was used.

[0210] [Table 1]

[0211]

[0212] The dimensional change rate of the transparent window longitudinal length before and after lamination (100(15-L) / 15) (unit: %) was calculated from the minimum value (L) (unit: mm) of the transparent window longitudinal length after lamination.

[0213] When making a transparent window, if the white core layer is thin, a portion of the transparent resin component of the laminating sheet will flow into the opening, resulting in a good appearance. Conversely, if the white core layer is thick, insufficient laminating sheet (transparent resin component) can flow in, resulting in bubbles in the transparent window or depressions on the surface. There are also cases where the white core layer itself flows in to fill the opening, making the transparent window smaller. Small dimensional changes in the transparent window mean that a transparent window with excellent appearance can be obtained.

[0214] <Lamination performance>

[0215] The resin sheets and laminating sheets obtained in the respective Examples and Comparative Examples were punched out into rectangles of 150 mm x 110 mm.

[0216] The punched laminating sheet was laminated on both surfaces of the resin sheet so that the surface A of the laminated sheet came into contact with the resin sheet obtained in each example or comparative example, and laminated under the conditions shown in Table 1 under heating and pressure to obtain a multilayer body.

[0217] Among them, the Ra of the surface A (the inner side of the multilayer body) was 0.99 μm.

[0218] The Ra of the multilayer body surface when laminated from top to bottom using 0.75 mm thick mirror SAS boards was 0.32 μm. Furthermore, the Ra of the multilayer body surface when laminated with Optilam, a release paper manufactured by Ahlstrom-Munksjo, sandwiched between the mirror SAS boards and the resin sheet was 2.17 μm.

[0219] For lamination, a tabletop card laminator OLA6E manufactured by OASYS was used.

[0220] [Table 2]

[0221]

[0222] The laminating properties of the obtained multilayer body were evaluated as follows: Evaluation was performed by five experts using a majority vote.

[0223] A: No appearance defects such as bubbles and poor adhesion were observed visually.

[0224] B: Other than the above A. For example, appearance defects such as bubbles and poor adhesion were observed visually.

[0225] <White Path>

[0226] The size of the cut sheet is 1m 2 The resin sheet was irradiated with S-Light manufactured by Japan Technology Center Co., Ltd. from a distance of 60 cm in the vertical direction of the sheet surface of the resin sheet. The side opposite to the irradiated side was visually observed, and the linear appearance defects with the longest part of more than 2 mm were regarded as "white stripes", and the number of white stripes was calculated.

[0227] The evaluation was conducted by 5 experts, and the average value (rounded off to the first decimal place) was calculated.

[0228] <Surface resistivity>

[0229] The antistatic properties of the resin composition of Example 14 were evaluated as follows.

[0230] The resin sheet to be measured was left at 23°C and 50% relative humidity for 24 hours or longer. A DC voltage of 1000 V was then applied for 300 seconds using a resistivity meter to measure surface resistivity (unit: Ω / sq.) at five locations, and the average value was calculated.

[0231] The surface resistivity of the resin sheet of Example 14 was 1.3×10 13 Ω / sq., and the surface resistivity of the back side is 2.0×10 13 Ω / sq.

[0232] The surface resistivity was measured using HIRESTA UP MCP-HT450 (manufactured by Mitsubishi Chemical ANALYTECH Corporation) with a URS probe.

[0233] [Table 3]

[0234]

[0235] [Table 4]

[0236]

[0237] [Table 5]

[0238]

[0239] [Table 6]

[0240]

[0241] Explanation of symbols

[0242] 10, 20, 30: multilayer body (security card); 11, 21, 31: covering layer (transparent resin sheet); 12, 22, 32: white core layer; 13: core layer; 23: transparent resin sheet; 24: transparent window; 25: opening (area where the white core layer does not exist); 33: transparent window (opening); 34: transparent core layer (transparent resin sheet).

Claims

1. A resin composition, characterized in that: The polycarbonate resin, titanium oxide and polyester are each 100 parts by mass, and the polycarbonate resin, titanium oxide and polyester are each 25 to 79.5 parts by mass, 0.5 to 40 parts by mass and 20 to 50 parts by mass, respectively. The content of titanium oxide in the resin composition is 20 to 50% by mass. The resin composition further contains a colorant other than titanium oxide at a ratio of 5 to 150 ppm by mass. The other colorant includes at least one of a colorant having a maximum absorption in the wavelength range of 450 to 650 nm and carbon black.

2. The resin composition according to claim 1, wherein: The glass transition temperature of the resin composition measured by DSC according to the method specified in JIS K7121:1987 is 100 to 155°C.

3. The resin composition according to claim 1 or 2, wherein: The melt volume flow rate (MVR) of the resin composition measured according to JIS K7210 is 2.0 to 50.0 cm 3 / 10min.

4. The resin composition according to claim 1 or 2, wherein: The viscosity average molecular weight of the polycarbonate resin is 20,000 to 35,000.

5. The resin composition according to claim 1 or 2, wherein: The resin composition contains a coloring agent other than the titanium oxide at a ratio of 10 to 80 ppm by mass.

6. The resin composition according to claim 1 or 2, wherein: The other colorant is a colorant having a maximum absorption in the wavelength range of 450 to 650 nm.

7. The resin composition according to claim 1 or 2, wherein: The other colorant is carbon black.

8. The resin composition according to claim 1 or 2, wherein: The other colorant includes a dye having a maximum absorption in the wavelength range of 450 to 650 nm.

9. The resin composition according to claim 1 or 2, wherein: The resin composition further contains an antioxidant at a ratio of 0.01 to 0.2% by mass.

10. The resin composition according to claim 1 or 2, wherein: Also contains antistatic agent.

11. The resin composition according to claim 1 or 2, wherein: The polyester includes an aliphatic polyester, and the content of the aliphatic polyester is 1 to 9 parts by mass.

12. The resin composition according to claim 11, wherein: The aliphatic polyester includes a structural unit derived from a lactone compound.

13. The resin composition according to claim 11, wherein: The aliphatic polyester comprises polycaprolactone.

14. The resin composition according to claim 1 or 2, wherein: The polyester includes an aromatic polyester, and the content of the aromatic polyester is 10 to 40 parts by mass.

15. The resin composition according to claim 1 or 2, wherein: It is used for cards.

16. A resin sheet, characterized in that: The resin composition is formed from the resin composition according to any one of claims 1 to 15.

17. The resin sheet according to claim 16, wherein: The thickness is 20 to 200 μm.

18. The resin sheet according to claim 16 or 17, wherein: The total light transmittance is 0 to 20%.

19. The resin sheet according to claim 16 or 17, wherein: When the total light transmittance of the resin sheet is T% and the thickness is t μm, T×t is 200 to 750.

20. The resin sheet according to claim 16 or 17, wherein: The surface roughness Ra of at least one surface of the resin sheet is 0.4 to 3.0 μm.

21. The resin sheet according to claim 16 or 17, wherein: The surface roughness Ra of the first surface of the resin sheet is 0.4 to 3.0 μm, and the surface roughness of the second surface is 0.1 to 2.5 μm smaller than the surface roughness of the first surface.

22. The resin sheet according to claim 16 or 17, wherein: On the sheet surface 1m 2 The number of foreign particles with a size of 0.5 mm or more, obtained by averaging the lengths of the long sides and the short sides, was 0 to 10 when observed under a microscope.

23. A multilayer body, characterized in that: A resin sheet according to any one of claims 16 to 22.

24. The multilayer body according to claim 23, wherein: The multilayer body comprises at least two resin sheets according to any one of claims 16 to 22, wherein the two resin sheets are located symmetrically with respect to a center plane of the cross section in a direction perpendicular to the thickness direction.

25. The multilayer body according to claim 23 or 24, characterized in that: At least one of the intermediate layer sheets constituting the multilayer body is the resin sheet according to any one of claims 16 to 22, and has at least one opening within the surface of the sheet.

26. The multilayer body according to claim 23 or 24, characterized in that: The multilayer body has a structure in which the resin sheet according to any one of claims 16 to 22, a transparent resin sheet, and the resin sheet according to any one of claims 16 to 22 are sequentially stacked.

27. The multilayer body according to claim 23 or 24, characterized in that: The surface roughness Ra of both surfaces of the multilayer body is 0.1 to 3.5 μm.

28. The multilayer body according to claim 23 or 24, characterized in that: The total thickness of the multilayer body is 0.2 to 2.0 mm.

29. The multilayer body according to claim 23 or 24, characterized in that: At least one layer of the multilayer body contains a laser color forming agent.

30. The multilayer body according to claim 23 or 24, characterized in that: It further comprises a layer containing a colorant that emits visible light when irradiated with ultraviolet rays or infrared rays.

31. The multilayer body according to claim 30, wherein: The invention further comprises a layer containing a colorant that emits visible light having a wavelength different from that of the colorant that emits visible light when irradiated with ultraviolet rays or infrared rays.

32. A card, characterized in that: The resin sheet according to any one of claims 16 to 22 or the multilayer body according to any one of claims 23 to 31 is included.

33. The card according to claim 32, wherein: It is a secure card.

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