JP2011025461A - Thin layer laminated sheet for laser marking, and laser marking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated sheet for laser marking which can be suitably used as label or others, for example, does not damage appearance when marking because the outer face layer is not removed by a laser beam, has a good contrast between printing parts and not printing parts (base parts), and can clearly mark characters, signals or others. <P>SOLUTION: The thin layer laminated sheet for laser marking has a thin layer laminated body with a thickness of 150 μm or more comprising a laser marking sheet layer and a transparent or colored auxiliary layer arranged in one face of the laser marking sheet layer, and is characterized in that the laminated body is constituted of a predetermined transparent laser marking sheet layer A with a thickness of 30 to 80 μm and a predetermined colored layer B with a thickness of 30 to 80 μm or a predetermined transparent protecting layer C and a predetermined colored laser marking sheet layer D with a thickness of 30 to 80 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thin-layer laminate sheet for laser marking and a laser marking method. More specifically, since the outer surface layer is not removed by the laser beam, the appearance is not damaged during marking, the surface is smooth, and the contrast between the printed part and the non-printed part (fabric part) is good. The present invention relates to a laminate sheet for laser marking and a laser marking method that can clearly mark characters, symbols, and the like and can be suitably used, for example, as a label.

  Currently, labels displaying production lots and the like are used in almost every field of industry. Conventionally, since this label has been manufactured by printing, a plurality of labels on which the same display is printed are manufactured together. That is, printing a different display for each sequentially manufactured label is not performed because it is necessary to replace the printing plate every time the display is changed, and the replacement work takes time.

  In order to produce a label by printing, specifically, the ink is transferred to the printing plate using a printing machine, the printing plate ink is printed on the base material, and then a label-shaped cutting die is used. Die cutting was done. In such a case, a printing press, a printing plate, and ink are required for each printing color, and a punching die is required for each label. For this reason, there are problems that enormous types of inks, printing plates, and punching dies are required depending on the type of display, and it takes time to manage and store these.

  Therefore, in recent years, in order to solve the above problems, labels (laser marking sheets) that are printed (marked) by laser marking have been developed. Specifically, the laser marking sheet includes a light-reflective metal plate and a light-absorbing colored layer provided on the metal plate, and irradiates the colored layer with a laser beam, thereby There is known a technique in which a colored layer is removed to expose a metal plate portion for marking (for example, see Patent Document 1).

  Since a desired display is printed on such a laser marking sheet by removing the colored layer with a laser beam, an arbitrary pattern can be easily formed with high work efficiency. In addition, a different display can be printed for each label. Furthermore, there is an advantage that a printing machine, a huge amount of ink, a printing plate, and a cutting die are not required.

  However, the laser marking sheet described in Patent Document 1 has a problem that it takes time to form the colored layer in addition to the need to previously form the colored layer. Moreover, since a light-reflective metal plate is used, there is a problem that the sheet becomes expensive. Further, since the surface has irregularities, it is difficult to remove the dirt due to the dirt entering the irregularities, and the function as a label is greatly deteriorated.

  In addition, as a sheet for laser marking, a sheet capable of displaying multiple colors has been reported (for example, see Patent Document 2). In addition to the advantages of the laser marking sheet described in Patent Document 1, the label described in Patent Document 2 has an advantage that a light-absorbing colored layer and a light-reflecting metal plate are not used.

  However, since the label described in Patent Document 2 needs to form many layers having different colors, its manufacturing method is complicated, and in order to obtain a predetermined color, a laser beam is used. However, it is necessary to engrave finely even a layer having a predetermined color (that is, an unnecessary layer is shaved with a laser beam), and there is a problem that it takes a lot of time for marking.

  Here, in recent years, there has been an increasing demand for prevention of counterfeiting and modification of various parts such as electrical and electronic equipment parts. From the viewpoint of satisfying such demands, the above-mentioned laser marking sheet has a multicolor It is not important to be able to display, and it is required that a personal name, a symbol, a character, a photograph, and the like can be clearly marked with good contrast. Furthermore, good productivity is also required.

  As such a sheet, specifically, for a laser marking comprising a surface layer made of a transparent thermoplastic resin and an inner layer made of a thermoplastic resin composition containing an energy absorber that absorbs a laser beam and a colorant. A thin-layer laminate sheet has been reported (see, for example, Patent Document 3).

  Further, an inner layer composed of a thermoplastic resin and a thermoplastic resin composition containing an energy absorber that absorbs a laser beam, a transparent thermoplastic resin disposed on one surface of the inner layer, and mica or A transparent first surface layer made of a thermoplastic resin composition containing carbon black, and a transparent second surface layer made of the thermoplastic resin composition disposed on the other surface of the inner layer. In addition, a thin laminate sheet for laser marking in which the composition ratio of the thicknesses of the first surface layer, the inner layer, and the second surface layer is a predetermined ratio has also been reported (for example, see Patent Document 4).

JP-A-5-333784 JP 2004-85827 A JP 2002-273732 A Japanese Patent No. 3889431

  The thin-layer laminate sheet for laser marking described in Patent Documents 3 and 4 is not printed by removing the outer surface layer (colored layer) with a laser beam, so that the appearance is not damaged during marking (printing). There is an advantage that the contrast between the printed portion and the non-printed portion (texture portion) is good, and the surface smoothness is good. Furthermore, the laser-marking thin-layer laminate sheet or the laser-marking thin-layer laminate sheet and the thermoplastic resin sheet (for example, PETG sheet, ABS resin sheet, etc.) are excellent in heat-fusibility and laser beam irradiation. With laser marking, the printability is sufficient to print characters and numbers.

  However, even in the thin-layer laminate sheet for laser marking described in Patent Documents 3 and 4, in particular, the inner layer described above (a layer that can be marked by a laser beam (hereinafter sometimes referred to as “laser marking layer”)) Is thin (specifically, less than 100 μm), the contrast between the printed portion and the non-printed portion is not yet sufficient, and the above contrast is excellent, and the display of characters, numbers, etc. can be clearly marked The development of a thin laminate sheet for laser marking has been eagerly desired.

  The present invention has been made to solve the above-described problems of the prior art, and since the outer surface layer is not removed by the laser beam, the appearance is not damaged during the marking, and the surface smoothness is eliminated. Excellent anti-counterfeiting and anti-counterfeiting performance, good contrast between printed part and non-printed part (material color), and can mark clear characters, symbols, images, etc. efficiently, such as laser marking labels The present invention provides a thin laminate sheet for laser marking, a laser marking label, and a laser marking method that can be suitably used as a material.

  According to the present invention, the following thin-layer laminate sheet for laser marking, a laser marking label, and a laser marking method are provided.

[1] A thin layered laminate sheet for laser marking comprising a laser marking sheet layer and a transparent or colored auxiliary layer disposed on one surface of the laser marking sheet layer, and comprising a laminate having a thickness of 150 μm or less. The laminate is composed of a transparent laser marking sheet layer A and a colored sheet layer B, or a transparent protective layer C and a colored laser marking sheet layer D, and the transparent laser marking sheet layer A is thick. The transparent laser marking sheet layer A having a single layer or a thickness of 30 to 80 μm is composed of a transparent polycarbonate-containing resin (1-1) mainly composed of a polycarbonate resin, and the polycarbonate-containing resin (1 -1) Transparent containing 0.0005 to 1 part by mass of energy absorber with respect to 100 parts by mass The multilayer transparent laser marking sheet layer A is a transparent sheet including a skin layer (a) and a core layer (a), and the skin layer (a) is a structural unit derived from terephthalic acid ( A-1), a structural unit (A-2) derived from ethylene glycol, and a structural unit (A-3) derived from 1,4-cyclohexanedimethanol, and a structural unit derived from ethylene glycol ( The content ratio ((A-2) / (A-3)) of the structural unit (A-3) derived from A-2) and the 1,4-cyclohexanedimethanol is 90/10 to 30/70 in molar ratio. A transparent amorphous polyester-containing resin (2-1) containing a copolymerized amorphous polyester resin as a main component,
The said core layer (a) is 0.0005-1 mass with respect to 100 mass parts of transparent polycarbonate containing resin (1-2) which has a polycarbonate resin as a main component, and the said polycarbonate containing resin (1-2). The ratio of the thickness of the core layer (a) to the total thickness of the skin layer (a) and the core layer (a) is 40 to 80%.

  The colored sheet layer B is a single layer or a multilayer having a thickness of 30 to 80 μm, and the single colored sheet layer B is a structural unit derived from terephthalic acid (B-1) or a structural unit derived from ethylene glycol. (B-2) and the structural unit (B-3) derived from 1,4-cyclohexanedimethanol, and the structural unit (B-2) derived from the ethylene glycol and the 1,4-cyclohexanedimethyl The main component is a copolymerized amorphous polyester resin in which the content ratio ((B-2) / (B-3)) of the structural unit (B-3) derived from methanol is 90/10 to 30/70 in molar ratio. The transparent amorphous polyester-containing resin (2-2) and the amorphous polyester-containing resin (2-2) 100 parts by mass are composed of a sheet containing 1 part by mass or more of a colorant. ,

  The multilayer colored sheet layer B is a sheet including a skin layer (b) and a core layer (b), and the skin layer (b) is composed of structural units derived from terephthalic acid (C-1), ethylene glycol. The structural unit (C-2) derived from 1,4-cyclohexanedimethanol and the structural unit (C-2) derived from the ethylene glycol are contained. Copolymerized amorphous polyester in which the content ratio of structural units (C-3) derived from 4-cyclohexanedimethanol ((C-2) / (C-3)) is 90/10 to 30/70 in molar ratio A transparent amorphous polyester-containing resin (2-3) containing a resin as a main component is contained, and the core layer (b) is a transparent polycarbonate-containing resin (1-3) containing a polycarbonate resin as a main component. ),as well as The core layer with respect to the total thickness of the skin layer (b) and the core layer (b), comprising 1 part by mass or more of a colorant with respect to 100 parts by mass of the polycarbonate-containing resin (1-3). The thickness ratio of (b) is 40-80%,

  The transparent protective layer C is a single layer or a multilayer that protects one surface of the colored laser marking sheet layer D, and the colored laser marking sheet layer D includes a skin layer (c) and a core layer (c). The skin layer (c) is derived from a structural unit (D-1) derived from terephthalic acid, a structural unit (D-2) derived from ethylene glycol, and 1,4-cyclohexanedimethanol. Containing the structural unit (D-3), the content ratio of the structural unit (D-2) derived from the ethylene glycol and the structural unit (D-3) derived from the 1,4-cyclohexanedimethanol ((D− 2) / (D-3)) contains a transparent amorphous polyester-containing resin (2-4) mainly composed of a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70. thing And the core layer (c) is 0.001 to 3 parts by mass with respect to 100 parts by mass of the polycarbonate-containing resin (1-4) and the polycarbonate-containing resin (1-4). The ratio of the thickness of the core layer (c) to the total thickness of the skin layer (c) and the core layer (c) is as follows. A thin laminate sheet for laser marking that is 40-80%.

[2] The single layer transparent laser marking sheet layer A is 0.01 to 3 parts by mass of lubricant and 0.1 to 5 parts by mass of oxidation with respect to 100 parts by mass of the polycarbonate-containing resin (1-1). At least one selected from the group consisting of an inhibitor, 0.1 to 5 parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and 0.1 to 5 parts by weight of a light stabilizer. Furthermore, the said transparent laser marking sheet layer A of a multilayer is 0.01-3 with respect to 100 mass parts of said non-crystalline polyester containing resin (2-1) in the said skin layer (a). Parts by weight lubricant, 0.1-5 parts by weight antioxidant, 0.1-5 parts by weight anti-coloring agent, 0.1-5 parts by weight UV absorber, and 0.1-5 parts by weight Further containing at least one selected from the group consisting of: In layer (a), with respect to 100 parts by mass of the polycarbonate-containing resin (1-2), 0.01 to 3 parts by mass of a lubricant, 0.1 to 5 parts by mass of an antioxidant, Or further containing at least one selected from the group consisting of 5 parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and 0.1 to 5 parts by weight of a light stabilizer, or In the skin layer (a), with respect to 100 parts by mass of the amorphous polyester-containing resin (2-1), 0.01 to 3 parts by mass of a lubricant, 0.1 to 5 parts by mass of an antioxidant, It further contains at least one selected from the group consisting of 0.1 to 5 parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and 0.1 to 5 parts by weight of a light stabilizer. In addition, in the core layer (a), 100 parts by mass of the polycarbonate-containing resin (1-2) 0.01 to 3 parts by weight of a lubricant, 0.1 to 5 parts by weight of an antioxidant, 0.1 to 5 parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and The thin-layer laminate sheet for laser marking according to [1], further containing at least one selected from the group consisting of 0.1 to 5 parts by mass of a light stabilizer.

[3] The transparent protective layer C is composed of a transparent laminate sheet or a transparent protective coat, and the transparent laminate sheet and the colored laser marking sheet layer D are bonded to each other with ethylene vinyl acetate or an acrylic adhesive. The thin-layer laminate sheet for laser marking according to [1] or [2].

[4] The energy absorber contained in the laminate is carbon black having an average particle diameter of 1 to 120 nm and a dibutyl phthalate oil absorption of 60 to 170 ml / 100 g. The thin-layer laminate sheet for laser marking as described.

[5] The thin-layer laminate sheet for laser marking according to any one of [1] to [4], and an adhesive layer formed on one surface of the thin-layer laminate sheet for laser marking. Laser marking label.

[6] A laser beam is irradiated from the transparent laser marking sheet layer A or the transparent protective layer C side of the thin layered laminate sheet for laser marking provided in the laser marking label according to [5]. Laser marking method for printing on laser marking labels.

  The thin laminate sheet for laser marking according to the present invention does not remove the outer surface layer with a laser beam, and therefore does not damage the appearance during marking, has excellent surface smoothness, anti-counterfeiting performance, and printing. The contrast between the portion and the non-printing portion is good, and there is an effect that clear characters, symbols, images and the like can be efficiently marked.

  Since the laser marking label of the present invention does not remove the outer surface layer with a laser beam, it does not damage the appearance during marking, has excellent surface smoothness, anti-counterfeiting performance, and printed and non-printed parts. The contrast of the image is good, and clear characters, symbols, images and the like can be efficiently marked.

  Since the laser marking method of the present invention does not remove the outer surface layer with a laser beam, it does not damage the appearance during marking, has excellent surface smoothness, anti-counterfeiting and anti-counterfeiting performance, and printed and non-printed parts. The contrast of the image is good, and clear characters, symbols, images and the like can be efficiently marked.

  Hereinafter, although the form for implementing this invention is demonstrated, this invention is not limited to the following embodiment. That is, it is understood that modifications and improvements as appropriate to the following embodiments are also within the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Thin layer laminate sheet for laser marking:
The thin laminate sheet for laser marking of the present invention comprises a laser marking sheet layer and a transparent or colored auxiliary layer disposed on one surface of the laser marking sheet layer, and has a thickness of 150 μm or less. A thin-layer laminate sheet for laser marking comprising the laminate comprising a transparent laser marking sheet layer A and a colored sheet layer B, or a transparent protective layer C and a colored laser marking sheet layer D It is.

  The transparent laser marking sheet layer A is a single layer or a multilayer having a thickness of 30 to 80 μm, and the single layer transparent laser marking sheet layer A is a transparent polycarbonate-containing resin (1-1) mainly composed of a polycarbonate resin, And it consists of a transparent sheet | seat containing 0.0005-1 mass part energy absorber with respect to 100 mass parts of polycarbonate containing resin (1-1).

  The multilayer transparent laser marking sheet layer A is a transparent sheet including a skin layer (a) and a core layer (a), and the skin layer (a) is a structural unit derived from terephthalic acid (A-1), Containing a structural unit (A-2) derived from ethylene glycol and a structural unit (A-3) derived from 1,4-cyclohexanedimethanol, and a structural unit (A-2) derived from ethylene glycol and 1 , 4-cyclohexanedimethanol content ratio ((A-2) / (A-3)) of the structural unit (A-3) is 90/10 to 30/70 in molar ratio. A transparent amorphous polyester-containing resin (2-1) containing a polyester resin as a main component is contained, and the core layer (a) is a transparent polycarbonate-containing resin (1) containing a polycarbonate resin as a main component. 2) and the polycarbonate-containing resin (1-2) with respect to 100 parts by mass, 0.0005 to 1 part by mass of energy absorber is contained, and the total of the skin layer (a) and the core layer (a) The ratio of the thickness of the core layer (a) to the thickness of 40 to 80%.

  The colored sheet layer B is a single layer or a multilayer having a thickness of 30 to 80 μm, and the single colored sheet layer B is a structural unit derived from terephthalic acid (B-1) or a structural unit derived from ethylene glycol (B -2) and a structural unit (B-3) derived from 1,4-cyclohexanedimethanol, derived from a structural unit (B-2) derived from ethylene glycol and 1,4-cyclohexanedimethanol A transparent composition mainly comprising a copolymerized amorphous polyester resin in which the content ratio ((B-2) / (B-3)) of the structural unit (B-3) is 90/10 to 30/70 in molar ratio. It consists of a sheet | seat containing 1 mass part or more of coloring agents with respect to 100 mass parts of non-crystalline polyester containing resin (2-2) and this non-crystalline polyester containing resin (2-2).

  The multilayer colored sheet layer B is a sheet including a skin layer (b) and a core layer (b), and the skin layer (b) is derived from a structural unit (C-1) derived from terephthalic acid and ethylene glycol. Containing the structural unit (C-2) and the structural unit (C-3) derived from 1,4-cyclohexanedimethanol, the structural unit (C-2) derived from ethylene glycol and 1,4-cyclohexanedi The main component is a copolymerized amorphous polyester resin in which the content ratio ((C-2) / (C-3)) of the structural unit (C-3) derived from methanol is 90/10 to 30/70 in molar ratio. A transparent amorphous polyester-containing resin (2-3), and the core layer (b) is a transparent polycarbonate-containing resin (1-3) mainly composed of a polycarbonate resin, and polycarbonate. Including The resin (1-3) contains 1 part by weight or more of a colorant with respect to 100 parts by weight of the core layer (b) relative to the total thickness of the skin layer (b) and the core layer (b). The ratio is 40-80%.

  The transparent protective layer C is a single layer or a multilayer that protects one surface of the colored laser marking sheet layer D.

  The colored laser marking sheet layer D includes a skin layer (c) and a core layer (c). The skin layer (c) is composed of a structural unit (D-1) derived from terephthalic acid, a structural unit (D-2) derived from ethylene glycol, and a structural unit derived from 1,4-cyclohexanedimethanol ( D-3) content ratio of structural unit (D-2) derived from ethylene glycol and structural unit (D-3) derived from 1,4-cyclohexanedimethanol ((D-2) / (D -3)) contains a transparent amorphous polyester-containing resin (2-4) mainly composed of a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70. The core layer (c) absorbs 0.001 to 3 parts by mass of energy with respect to 100 parts by mass of the transparent polycarbonate-containing resin (1-4) and polycarbonate-containing resin (1-4) mainly composed of polycarbonate resin. And a ratio of the thickness of the core layer (c) to the total thickness of the skin layer (c) and the core layer (c) is 40 to 80%.

  The thin layered laminate sheet for laser marking having the above-described configuration is not damaged in appearance at the time of marking because the laser marking sheet layer is not removed by the laser beam. In addition, since the surface portion is removed and no marking is performed, the surface smoothness and the anti-counterfeiting performance are excellent. In addition, the laser marking sheet layer and the auxiliary layer combine to obtain a good contrast between the printed portion and the non-printed portion, so that clear characters, symbols, images, etc. can be printed efficiently. As described above, the thin laminate sheet for laser marking according to the present invention has the above-described effects despite its thickness being 150 μm or less, and further, since the thickness is sufficiently thin, It can be suitably used for a label on which a lot or the like is displayed.

  As described above, since the thickness of the thin laminate sheet for laser marking of the present invention is 150 μm or less, it can be suitably used as a material for sheets such as labels and label-type tags. Among these, it is preferable to use as a sheet for labels.

  The laser marking sheet layer is a layer that is marked with a laser beam and the surface portion is not removed at that time. Either a transparent or colored sheet may be used, and this laser marking sheet is a sheet on which a desired character, symbol, image, or the like is marked when a laser beam is irradiated so that the irradiated portion is colored.

  The auxiliary layer is a transparent or colored layer disposed on one side of the laser marking sheet layer. By providing such an auxiliary layer, even if the thickness is 150 μm or less, the auxiliary layer is not Good contrast in the printed part can be obtained. And if it is a transparent auxiliary layer, it will be falsified and counterfeited in order to effectively protect its surface without degrading the clarity of characters, symbols, images etc. marked on the colored laser marking sheet layer A laminate sheet having excellent prevention performance can be obtained. Moreover, when it is a colored auxiliary layer, it is possible to obtain a laminate sheet having a better contrast between the printed portion and the non-printed portion.

  The thickness of the laminar laminate sheet for laser marking is 150 μm or less, preferably 60 to 140 μm, more preferably 80 to 120 μm from the viewpoint of use as a label sheet. When the thickness is more than 150 μm, the rigidity of the sheet becomes too large, and when used for a label, the label may be easily peeled off when attached to a curved surface, etc. Will not work.

  Hereinafter, one embodiment of the thin-layer laminate sheet for laser marking of the present invention will be described.

  In the thin-layer laminate sheet for laser marking according to this embodiment, the laminate constituting the thin-layer laminate sheet for laser marking has a thickness of 30 to 80 μm and a transparent laser marking sheet layer A (laser marking sheet layer). It is a laminate formed by laminating 30 to 80 μm colored sheet layer B (auxiliary layer), and has a total thickness of 150 μm or less. The thin laminate sheet for laser marking having such a configuration has an advantage that the contrast between the printed portion and the non-printed portion is particularly good while the laser marking layer is thin (specifically, less than 100 μm). .

[1-1] Transparent laser marking sheet layer A:
The transparent laser marking sheet layer A (hereinafter sometimes referred to as “transparent laser marking sheet A”) is a transparent laser marking sheet (laser marking layer). When the body sheet is used for a label or the like, the transparent laser marking sheet A is positioned on the surface side of the colored sheet layer B (hereinafter sometimes referred to as “colored sheet B”), and displays characters and the like It becomes a surface.

  The transparent laser marking sheet A is a single layer or a multilayer, and the thickness thereof needs to be 30 to 80 μm as described above, and preferably 40 to 60 μm. If the thickness is less than 30 μm, there is a problem that the color developability by laser marking is lowered. On the other hand, if it exceeds 80 μm, there is a problem that the thickness of the entire laminate is too thick and the rigidity of the label is increased.

  The transparency of the transparent laser marking sheet A is not limited as long as characters marked on the transparent laser marking sheet A appear clearly due to the contrast with the colored sheet B, but the total light transmittance is preferably 70% or more. And more preferably 85% or more.

  In this specification, the total light transmittance is a value measured in accordance with JIS-K7105. The measurement of the total light transmittance is, for example, a haze meter (trade name: “NDH 2000” manufactured by Nippon Denshoku Industries Co., Ltd.). ), A spectrophotometer (trade name “EY7000” manufactured by Macbeth Co., Ltd.) and the like.

[1-1-1] Single-layer transparent laser marking sheet layer A:
The single-layer transparent laser marking sheet layer A (hereinafter sometimes referred to as “single-layer transparent laser marking sheet A”) is a transparent polycarbonate-containing resin (1-1) mainly composed of a polycarbonate resin, and It consists of a transparent sheet | seat containing 0.0005-1 mass part energy absorber with respect to 100 mass parts of this polycarbonate containing resin (1-1). Such a single-layer sheet is excellent in laser color development (black color development). In particular, when compared with a label for printing or the like (that is, a label in which an ink layer is attached only on the surface), the laser-marked thin layered laminate sheet of the present invention is colored by the transparent laser marking sheet A. Therefore, the marking portion is excellent in wear resistance.

  As the polycarbonate resin in the polycarbonate-containing resin (1-1), those having a melt volume rate of 2 to 30 are preferable. When the melt volume rate is less than 2, the mechanical properties are excellent and the sheet has excellent toughness, but the melt extrusion moldability may be inferior. On the other hand, if the melt volume rate is more than 30, the melt extrusion moldability is excellent, but the toughness of the sheet may be inferior. In the present specification, “melt volume rate” is a value measured in accordance with ISO 1133 (JIS K7210) using a “melt indexer” manufactured by Leo Lab.

  Specific examples of the polycarbonate resin satisfying the melt volume rate in the above range include “Taflon A2600” and “A2200” manufactured by Idemitsu Kosan Co., Ltd., “Panlite L-1225Y” and “L-1300Y” manufactured by Teijin Chemicals. And so on.

  The polycarbonate-containing resin (1-1) can be mixed with other components in addition to the polycarbonate resin as long as the performance is not impaired. Examples of other components include polyarylate that is excellent in compatibility with a polycarbonate resin.

  The content ratio of the polycarbonate resin in the polycarbonate-containing resin (1-1) is preferably 50 to 100% by mass, and 80 to 100% by mass with respect to the total amount of the polycarbonate-containing resin (1-1). Is more preferable. When the content ratio is less than 50% by mass, strength characteristics such as impact strength of the transparent laser marking sheet A are deteriorated, so that the transparent laser marking sheet A may be easily cracked during production. When a label manufactured using the transparent laser marking sheet A is attached to a curved surface, the label may easily crack.

  The energy absorber is a compound that absorbs a laser beam, converts the light into heat energy, carbonizes the polycarbonate resin with the generated heat, and performs black printing (marking). As the energy absorber, for example, at least one selected from the group of carbon black, metal oxide, metal sulfide, and metal nitride can be used.

  Carbon black is classified into furnace black, channel black, thermal black, etc. depending on its production method, and acetylene black, ketjen black, oil black, gas black, etc. depending on the raw material. Can be used. The average particle diameter is preferably 1 to 120 nm, more preferably 3 to 100 nm, and particularly preferably 5 to 80 nm. If the average particle size of the carbon black is less than 1 nm, heat generation due to laser irradiation is small and the color developability may be poor. On the other hand, if it exceeds 120 nm, too much heat is generated by the irradiation of the laser beam, the resin may be discolored by this heat, and the contrast of the coloring portion may be lowered. Here, the “average particle diameter” in the present specification is an average of measured values obtained by measuring the diameters of a plurality of particles with a transmission electron microscope.

  The energy absorber used for the thin-layer laminate sheet for laser marking of the present invention is preferably a carbon black with a dibutyl phthalate oil absorption of 60 to 170 ml / 100 g, and a dispersion of less than 60 ml / 100 g. May be worse. On the other hand, if it is more than 170 ml / 100 g, there is a risk of poor incompatibility.

  As metal oxides, metal sulfides, and metal nitrides, various metal oxides, sulfides, and nitrides can be used, and composite metal oxides and the like can also be suitably used. Examples of the metal forming the metal oxide include zinc, magnesium, aluminum, iron, titanium, silicon, antimony, tin, copper, manganese, cobalt, bismuth, vanadium, niobium, molybdenum, ruthenium, tungsten, palladium, silver, Platinum etc. are mentioned. Further, examples of the composite metal oxide include ITO, ATO, AZO and the like. Examples of the metal sulfide include zinc sulfide and cadmium sulfide. Examples of the metal nitride include titanium nitride.

  Thus, as the energy absorber, carbon black, titanium black, metal oxide, and composite metal oxide can be suitably used, and these can be used alone or in combination.

  In the case of the single layer transparent laser marking sheet A, the addition amount (blending amount) of the energy absorber is 0.0005 to 1 part by mass with respect to 100 parts by mass of the polycarbonate-containing resin (1-1). It is preferable that it is 0.001-0.1 mass part, and it is still more preferable that it is 0.001-0.01 mass part. When the amount of the energy absorber is less than 0.0005 parts by mass, a sufficient contrast cannot be obtained because heat generation due to laser beam irradiation is small. On the other hand, if it exceeds 1 part by mass, the energy absorption amount of the laser beam is excessive, resulting in a decrease in contrast and a decrease in transparency.

  In addition to the polycarbonate-containing resin (1-1) and the energy absorber, the single-layer transparent laser marking sheet A contains additives such as a lubricant, an antioxidant, an anti-coloring agent, an ultraviolet absorber, and a light stabilizer. be able to. These can be used alone or in combination.

  When using the said additive, 0.01-3 mass parts lubricant, 0.1-5 mass parts antioxidant, 0.1-5 with respect to 100 mass parts of polycarbonate containing resin (1-1). It is preferable to further contain at least one selected from the group consisting of parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and 0.1 to 5 parts by weight of a light stabilizer. By further containing each component under such conditions, there are advantages that the stability of the resin at the time of melt extrusion molding is improved and that the deterioration with time at the time of actual use is suppressed.

  Examples of the lubricant include fatty acid esters, fatty acid amides, and fatty acid metal salts.

  Examples of fatty acid esters include butyl stearate, cetyl palmitate, stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, montan wax acid ester, wax ester, dicarboxylic acid ester, and complex ester. Examples of fatty acid amides include stearic acid amide and ethylene bisstearyl amide. Examples of the fatty acid metal salt include calcium stearate, magnesium stearate, zinc stearate, aluminum stearate, barium stearate and the like.

  As described above, the content of the lubricant is preferably 0.01 to 3 parts by mass, and preferably 0.05 to 0.5 parts by mass. If the content is less than 0.01 parts by mass, the effect of improving the stability of the resin during molding may not be sufficiently obtained. On the other hand, if it exceeds 3 parts by mass, the resin is highly slippery and slips in the extrusion molding machine during molding, which may make sheet molding difficult.

  As antioxidant, a phenolic antioxidant etc. can be mentioned, for example. Examples of the phenol-based antioxidant include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 3 -5-di-t-butyl-4-hydroxytoluene; pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- ( 3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2- tert-butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4- Tylphenyl acrylate, 2,6-di-tert-butyl-4- (N, N-dimethylaminomethyl) phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2′- Methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-methylenebis (2,6-di-tert-butylphenol), 2 , 2′-methylenebis (4-methyl-6-cyclohexylphenol), 2,2′-dimethylene-bis (6-α-methyl-benzyl-p-cresol), 2,2′-ethylidene-bis (4,6 -Di-tert-butylphenol), 2,2'-butylidene-bis (4-methyl-6-tert-butylphenol) Lumpur),

  4,4′-butylidenebis (3-methyl-6-tert-butylphenol), triethylene glycol-N-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, 1,6- Hexanediol bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis [2-tert-butyl-4-methyl 6- (3-tert-butyl-5-methyl-) 2-hydroxybenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1, -dimethylethyl} -2 , 4,8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (6-tert-butyl-m-crezo ), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3,5-di-tert-butyl) -4-hydroxybenzyl) sulfide, 4,4'-di-thiobis (2,6-di-tert-butylphenol), 4,4'-tri-thiobis (2,6-di-tert-butylphenol), 2, 2-thiodiethylenebis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) -6- (4-hydroxy-3 ′, 5 '-Di-tert-butylanilino) -1,3,5-triazine,

  N, N′-hexamethylenebis- (3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N, N′-bis [3- (3,5-di-tert-butyl-4- Hydroxyphenyl) propionyl] hydrazine, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxyphenyl) isocyanurate, tris (3,5-di-tert-butyl-4-hydroxy) Benzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4 tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris 2 [3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate , Tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane and the like.

  Among these, n-octadecyl-3- (3,5-di-tert-butyl-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert- Butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionyloxymethyl] methane is preferred, and n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate is more preferred. In addition, the said phenolic antioxidant can be used individually by 1 type or in combination of 2 or more types.

  Examples of the coloring inhibitor include phosphite compounds. Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite Phyto, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, tris (diethylphenyl) phosphite, tris (Di-iso-propylphenyl) phosphite, tris (di-n-butylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2,6- -Tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-) Methylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite Phyto, dicyclohexyl pentaerythritol diphosphite, etc. are mentioned.

  Other phosphite compounds that react with dihydric phenols and have a cyclic structure can also be used. For example, 2,2′-methylenebis (4,6-di-tert-butylphenyl) (2,4-di-tert-butylphenyl) phosphite, 2,2′-methylenebis (4,6-di-tert- Butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite, 2,2′-methylenebis (4-methyl-6-tert-butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite 2,2′-ethylidenebis (4-methyl-6-tert-butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite.

  Among these, tris (2,4-di-tert-butylphenyl) phosphite is preferable. In addition, a coloring inhibitor can be used individually by 1 type or in combination of 2 or more types. Moreover, you may use together with a phenolic antioxidant.

  Antioxidants and anti-coloring agents can be used to suppress problems such as the thermal oxidation reaction of the polycarbonate resin in the melt-extrusion molding process and thermal discoloration resulting therefrom. It is preferable that it is 1-5 mass parts. If the content is less than 0.1 parts by mass, these effects may not be sufficiently obtained. On the other hand, if it exceeds 5 parts by mass, problems such as occurrence of bleeding of the antioxidant and the coloring agent are likely to occur, which is not preferable.

  Examples of the ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, 2 -(2'-hydroxy-3 ', 5'-bis (α, α'-dimethylbenzyl) phenylbenzotriazole, 2,2'methylenebis [4- (1,1,3,3-tetramethylbutyl) -6 -(2H-benzotriazol-2-yl) phenol], condensation with methyl-3- [3-tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenylpropionate-polyethylene glycol Examples thereof include benzotriazole compounds typified by products such as 2- (4,6-diphenyl-1,3,5-trimethyl). Azin-2-yl) -5-hexyloxyphenol, 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hexyloxyphenol, etc. Hydroxyphenyltriazine compounds, and 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2′-m-phenylenebis (3,1-benzoic acid). And cyclic imino ester compounds such as 2,2′-p, p′-diphenylenebis (3,1-benzoxazin-4-one).

  Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2 , 2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2 , 3,4-Butanetetracarboxylate, poly {[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2, 6,6-tetramethylpiperidyl) imino] hexamethylene [(2,2,6,6-tetramethylpiperidyl) imino]}, polymethylpropyl 3-oxy- [4- (2,2,6,6-tetra Methyl) pipette Jiniru] can be exemplified hindered amine represented by a siloxane. Such a light stabilizer has an advantage of exhibiting better performance in terms of weather resistance and the like when used in combination with an ultraviolet absorber or, in some cases, various antioxidants.

  The contents of the ultraviolet absorber and the light stabilizer are each preferably 0.1 to 5 parts by mass, and if the content is less than 0.1 parts by mass, the effect may not be sufficiently obtained. There is a risk of problems such as light resistance deterioration and discoloration associated therewith. On the other hand, if it exceeds 5 parts by mass, problems such as the occurrence of bleeding of ultraviolet absorbers and light stabilizers are likely to occur, which is not preferable.

  The single-layer transparent laser marking sheet A can be obtained, for example, by obtaining a kneaded product containing the above components and molding the obtained kneaded product by melt extrusion molding. In addition, as described above, the transparent laser marking sheet A is preferably mat-processed after being formed by melt extrusion molding. By this mat processing, the average roughness (Ra of at least one surface of the transparent laser marking sheet A) ) Is preferably 0.1 to 5 μm. In particular, when the average roughness (Ra) of the surface on the colored sheet B side is less than 0.1 μm, bubbles are sufficiently removed when both sheets (the transparent laser marking sheet A and the colored sheet B) are heat-sealed. There is a risk of disappearing. On the other hand, if it exceeds 5 μm, it is not preferred because there is a possibility that the heat-fusibility is lowered. Here, in this specification, the average roughness (Ra) is a value measured by “Tarisurf” manufactured by Taylor Hobson.

[1-1-2] Multilayer transparent laser marking sheet layer A:
The multilayer transparent laser marking sheet layer A (hereinafter sometimes referred to as “multilayer transparent laser marking sheet A”) is a transparent sheet including a skin layer (a) and a core layer (a). (A) is a structural unit derived from terephthalic acid (A-1), a structural unit derived from ethylene glycol (A-2), and a structural unit derived from 1,4-cyclohexanedimethanol (A-3). Content ratio of structural unit (A-2) derived from ethylene glycol and structural unit (A-3) derived from 1,4-cyclohexanedimethanol ((A-2) / (A-3)) Contains a transparent amorphous polyester-containing resin (2-1) mainly composed of a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70. And a core layer (a) is 0.0005-1 with respect to 100 mass parts of transparent polycarbonate containing resin (1-2) which has polycarbonate resin as a main component, and this polycarbonate containing resin (1-2). It contains an energy absorber in part by mass, and the ratio of the thickness of the core layer (a) to the total thickness of the skin layer (a) and the core layer (a) is 40 to 80%. When this multi-layer transparent laser marking sheet A is irradiated with laser light, the energy absorber that has passed through the skin layer (a) and dispersed in the core layer (a) absorbs the energy of the laser beam to generate black color. On the other hand, the skin layer (a) is smooth because it does not easily cause the change. And there exists an advantage that it is excellent in abrasion resistance resulting from having this skin layer (a).

  As described above, the multilayer transparent laser marking sheet A is not particularly limited as long as it is a transparent sheet comprising a skin layer (a) and a core layer (a). For example, the skin layer (a) and the core layer (a) may each have one layer, and these may be arranged in a stacked state, or the skin layer (a) may be a first layer. It consists of a plurality of layers having a skin layer (a-1) and a second skin layer (a-2), and the first skin layer (a-1) is laminated on one surface side of the core layer (a). Arranged in a state where the second skin layer (a-2) is laminated on the other surface side (ie, the first skin layer (a-1) / core layer (a)) / A laminate comprising the second skin layer (a-2)).

  Examples of the copolymerized amorphous polyester resin contained in the skin layer (a) include “Easter GN071” manufactured by Eastman Chemical Co., Ltd.

  Specifically, the content of the copolymerized amorphous polyester resin is preferably 50 to 100% by mass, and preferably 80 to 100% by mass with respect to the total amount of the amorphous polyester-containing resin (2-1). More preferably. If the content is less than 50% by mass, printability and heat-fusibility may be deteriorated.

  As the polycarbonate resin in the polycarbonate-containing resin (1-2) contained in the core layer (a), the same resin as the polycarbonate resin in the polycarbonate-containing resin (1-1) can be used at the same ratio.

  Content of the energy absorber contained in a core layer (a) is 0.0005-1 mass part with respect to 100 mass parts of polycarbonate containing resin (1-2), and 0.001-0.1 mass. Parts, preferably 0.001 to 0.01 parts by mass. When the amount of the energy absorber is less than 0.0005 parts by mass, a sufficient contrast cannot be obtained because heat generation due to laser beam irradiation is small. On the other hand, if it exceeds 1 part by mass, the energy absorption amount of the laser beam is excessive, resulting in a decrease in contrast and a decrease in transparency.

  Further, in the multilayer transparent laser marking sheet A, as in the case of the single-layer transparent laser marking sheet A, at least one of the skin layer (a) and the core layer (a) is provided with a lubricant, an antioxidant, and an anti-coloring agent. Additives such as an agent, an ultraviolet absorber, and a light stabilizer can be contained, and these can be used alone or in combination.

  Specifically, the multilayer transparent laser marking sheet A has a lubricant of 0.01 to 3 parts by mass with respect to 100 parts by mass of the amorphous polyester-containing resin (2-1) in the skin layer (a). From 0.1 to 5 parts by weight of antioxidant, 0.1 to 5 parts by weight of coloring inhibitor, 0.1 to 5 parts by weight of UV absorber, and 0.1 to 5 parts by weight of light stabilizer The core layer (a) further contains at least one selected from the group consisting of 0.01 to 3 parts by mass of a lubricant with respect to 100 parts by mass of the polycarbonate-containing resin (1-2), 0.1 From the group consisting of -5 parts by weight of antioxidant, 0.1-5 parts by weight of coloring inhibitor, 0.1-5 parts by weight of UV absorber, and 0.1-5 parts by weight of light stabilizer. At least one selected from the above, or in the skin layer (a), an amorphous polyester 0.01 to 3 parts by mass of lubricant, 0.1 to 5 parts by mass of antioxidant, 0.1 to 5 parts by mass of anti-coloring agent with respect to 100 parts by mass of resin (2-1); While further containing at least one selected from the group consisting of 1 to 5 parts by weight of an ultraviolet absorber and 0.1 to 5 parts by weight of a light stabilizer, the core layer (a) contains a polycarbonate-containing resin ( 1-2) 0.01-3 parts by mass of lubricant, 0.1-5 parts by mass of antioxidant, 0.1-5 parts by mass of anti-coloring agent, 0.1-5 parts per 100 parts by mass It is preferable to further contain at least one selected from the group consisting of parts by mass of an ultraviolet absorber and 0.1 to 5 parts by mass of a light stabilizer.

  Further, as described above, the ratio of the thickness of the core layer (a) to the total thickness of the skin layer (a) and the core layer (a) needs to be 40 to 80%, and is 60 to 75%. Preferably there is. When the ratio of the thickness of the core layer (a) is less than 40%, in addition to being inferior in laser colorability, strength and heat resistance are not sufficient. On the other hand, if it exceeds 80%, for example, a multilayer transparent laser marking sheet A composed of the first skin layer (a-1) / core layer (a) / second skin layer (a-2) is formed. In this case, it is difficult to uniformly form the skin layers (a) (first skin layer (a-1) and second skin layer (a-2)) disposed on both sides of the core layer (a). Become.

  The multilayer transparent laser marking sheet A is obtained by, for example, obtaining each composition (kneaded material) for constituting the core layer (a) and the skin layer (a), and using each obtained kneaded material with two extruders. Can be obtained by melt coextrusion with a T die, and the multilayer transparent laser marking sheet A can be matted with a mat roll immediately after coming out of the T die.

[1-2] Colored sheet layer B:
The colored sheet B (auxiliary layer) is a single layer or a multilayer having a thickness of 30 to 80 μm. The single-layer colored sheet B is composed of a structural unit derived from terephthalic acid (B-1), a structural unit derived from ethylene glycol (B-2), and a structural unit derived from 1,4-cyclohexanedimethanol. The content ratio ((B-2) / () of the structural unit (B-3) containing (B-3) and derived from ethylene glycol and the structural unit (B-3) derived from 1,4-cyclohexanedimethanol. B-3)) a transparent amorphous polyester-containing resin (2-2) mainly comprising a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70, and the amorphous The polyester-containing resin (2-2) is a sheet containing 1 part by mass or more of a colorant with respect to 100 parts by mass. By providing such a colored sheet B, there is an advantage that a good contrast between the printed portion and the non-printed portion of the transparent laser marking sheet A is obtained, and the printed portion becomes clear.

  As a copolymerization non-crystalline polyester resin in non-crystalline polyester containing resin (2-2), the brand name "Easter GN071" by Eastman Chemical Co., etc. can be mentioned, for example.

  Specifically, the content of the copolymerized amorphous polyester resin is preferably 50 to 100% by mass, and preferably 80 to 100% by mass with respect to the total amount of the amorphous polyester-containing resin (2-2). More preferably. If the content is less than 50% by mass, printability and heat-fusibility may be deteriorated.

  The non-crystalline polyester-containing resin (2-2) can further contain a polycarbonate resin in addition to the copolymer non-crystalline polyester resin. That is, as the non-crystalline polyester-containing resin (2-2), a mixture (alloy) of a copolymer non-crystalline polyester resin and a polycarbonate resin can also be suitably used, and the mass ratio of the polycarbonate resin in the alloy is 0. It is preferably less than ˜50% by mass, more preferably less than 40% by mass, and particularly preferably less than 30% by mass. If the mass ratio of the polycarbonate resin is 50% by mass or more, printability, adhesiveness, and heat fusion with the transparent laser marking sheet A may be deteriorated.

  Examples of the colorant include inorganic pigments, organic pigments, dyes, and the like. Examples of inorganic pigments include white pigments, yellow pigments, red pigments, and blue pigments. Examples of white pigments include titanium oxide, barium sulfate, zinc sulfide, and zinc oxide. Examples of yellow pigments include iron oxide and titanium yellow. Examples of red pigments include iron oxide. Examples of blue pigments include cobalt blue and ultramarine blue. Examples of the organic pigment include monoazo, condensed azo, anthraquinone, disazo, heterocycle, quinacridone, anthraquinone, perylene, monoazo, phthalocyanine, and phthalocyanine. Examples of the dye include monoazo, anthraquinone, disazo, heterocycle, anthraquinone, perinone, thioindigo, disazo, anthraquinone and the like.

  Any of these colorants can be appropriately selected and used, but the purpose of using the colored sheet B is to sharpen a printed portion such as characters generated by laser coloring of the transparent laser marking sheet A, Considering that the color of the printed portion is specifically black, it is preferably a white or light-colored color with which a good contrast can be obtained with respect to this black, and in particular, a white color is preferable.

  As described above, the blending amount of the colorant needs to be 1 part by mass or more and 1 to 10 parts by mass with respect to 100 parts by mass of the non-crystalline polyester-containing resin (2-2). Is preferred. When the blending amount is less than 1 part by mass, the contrast between the printed part and the non-printed part cannot be obtained sufficiently. Moreover, there exists a possibility that a physical property may fall that it is more than 10 mass parts.

  The single-layer colored sheet B can be obtained, for example, by obtaining a kneaded product containing the above-described components and molding the obtained kneaded product by melt extrusion molding.

  The multilayer colored sheet B is a sheet including a skin layer (b) and a core layer (b). As long as the multilayer colored sheet B is a sheet including a skin layer (b) and a core layer (b), the laminated structure is not particularly limited. For example, the skin layer (b) and the core layer (b) may each have one layer, and these may be arranged in a stacked state, or the skin layer (b) may be a first layer. It consists of a plurality of layers having a skin layer (b-1) and a second skin layer (b-2), and the first skin layer (b-1) is laminated on one surface side of the core layer (b). Arranged in a state where the second skin layer (b-2) is laminated on the other surface side (ie, the first skin layer (b-1) / core layer (b) / A laminate comprising the second skin layer (b-2)).

  The skin layer (b) of the multilayer colored sheet B contains the non-crystalline polyester-containing resin (2-3) described above, and is a copolymerized amorphous material in the non-crystalline polyester-containing resin (2-3). As the polyester resin, those similar to the copolymerized amorphous polyester resin in the amorphous polyester-containing resin (2-1) can be used at the same ratio.

  As described above, the core layer (b) of the multilayer colored sheet B is composed of a transparent polycarbonate-containing resin (1-3) mainly composed of a polycarbonate resin, and 100 parts by mass of the polycarbonate-containing resin (1-3). On the other hand, it contains 1 part by mass or more of a colorant. As the polycarbonate resin in the polycarbonate-containing resin (1-3) contained in the core layer (b), the same resin as the polycarbonate resin in the polycarbonate-containing resin (1-1) can be used at the same ratio. Moreover, the said coloring agent contained in a core layer (b) can use the thing similar to the coloring agent contained in the single colored sheet B mentioned above with the same compounding quantity.

  The thickness of the colored sheet B is required to be 30 to 80 μm and preferably 30 to 60 μm in both cases of a single layer and a multilayer. If the thickness is less than 30 μm, sufficient contrast between the printed portion and the non-printed portion cannot be obtained. On the other hand, when it exceeds 80 μm, the thickness of the entire laminate sheet is increased and the rigidity becomes too large, and therefore, when the obtained label is applied to a curved surface or the like, it is peeled off (does not sufficiently function as a label).

  Further, as described above, the ratio of the thickness of the core layer (b) to the total thickness of the skin layer (b) and the core layer (b) needs to be 40 to 80%, and is 60 to 75%. Preferably there is. When the ratio of the thickness of the core layer (b) is less than 40%, in addition to inferior laser color developability, strength and heat resistance are not sufficient. On the other hand, when it exceeds 80%, for example, when a laminate composed of the first skin layer (b-1) / core layer (b) / second skin layer (b-2) is molded, the core layer It becomes difficult to uniformly form the skin layers (b) (first skin layer, second skin layer (b-2)) disposed on both sides of (b).

  The multilayer colored sheet B can be obtained, for example, by a method of melt coextrusion with a T die using an extruder in the same manner as the multilayer transparent laser marking sheet A.

[1-3] Formation of thin laminate sheet for laser marking:
The thin laminate sheet for laser marking of this embodiment can be obtained by laminating the transparent laser marking sheet A and the colored sheet B by a conventionally known method. Specifically, in a state where the transparent laser marking sheet A and the colored sheet B are laminated, an adhesive such as an acrylic adhesive is applied in advance to one surface of the transparent laser marking sheet A by heat fusion with a pressure / heating roller. (It is generally applied so as to form a layer having a thickness of about 5 to 30 μm), and can be obtained by adhering to each other by pressurization or heating / pressurization.

  Next, another embodiment of the thin laminate sheet for laser marking of the present invention will be described.

  The thin laminate sheet for laser marking of this embodiment is a laminate obtained by laminating a transparent protective layer C (auxiliary layer) and a colored laser marking sheet layer D (laser marking sheet layer) having a thickness of 30 to 80 μm. The total thickness is 150 μm or less. The transparent protective layer C of the laminated sheet for laser marking having such a configuration is a layer for protecting the colored laser marking sheet layer D. Further, the energy absorbing agent dispersed in the colored laser marking sheet layer D is irradiated with a laser beam and absorbs the energy of the laser beam, and the visibility of the colored printed portion (marking portion) is also improved by the transparent protective layer C. Furthermore, there is an advantage that the marking portion is excellent in smoothness, abrasion resistance, and chemical resistance. Moreover, when forming the printing layer by printing on the surface of the colored laser marking sheet layer D entirely or partially, the transparent protective layer C can be used for the purpose of protecting the printing layer.

[2-1] Transparent protective layer C:
The transparent protective layer C is a transparent single layer or multilayer that protects one surface of the colored laser marking sheet layer D. The transparent protective layer C is not particularly limited as long as it is such a layer. Specifically, the transparent protective layer C is preferably composed of a transparent laminate sheet or a transparent protective coat film.

  The transparent laminate sheet is a sheet containing at least one selected from the group consisting of a polyester resin, a polypropylene resin, a nylon resin, and a polyethylene vinyl alcohol resin. Such a transparent laminate sheet is advantageous in that it is excellent in transparency and excellent in scratch resistance, abrasion resistance, chemical resistance, water resistance, weather resistance, discoloration resistance, and the like. And as for a transparent laminate sheet, it is preferable to use what has already apply | coated ethylene vinyl acetate or acrylic adhesive on the single side | surface (colored laser marking sheet layer D side surface). That is, it is preferable that the transparent laminate sheet and the colored laser marking sheet layer D are bonded to each other with ethylene vinyl acetate or an acrylic adhesive.

  The thickness of the transparent laminate sheet is preferably 10 to 50 μm, and more preferably 15 to 35 μm. When the thickness is less than 10 μm, handling at the time of lamination may be difficult (productivity may be insufficient), and production is difficult and very expensive, and there is a possibility that it cannot be used widely. On the other hand, if it exceeds 50 μm, the laminate has a high rigidity, and there is a possibility that a problem of peeling off with time may occur when the laminate is attached to a curved surface.

  The transparent protective coating film can be formed using various protective coating agents as materials, and examples of the protective coating agent include water-based and solvent-based ones. Examples of the solvent-based ones include thermosetting acrylic hard coating agents, UV curable acrylic hard coating agents, acrylic urethane reactive coating agents, and organic / inorganic hybrid coating agents. The transparent protective coating film can be formed, for example, by applying a water-based or solvent-based coating agent on the surface of the colored laser marking sheet layer D in the form of a film. Among the coating agents, a curable coating agent such as UV curing or thermosetting is preferably used from the viewpoint that a transparent protective coating film having good solvent resistance and scratch resistance can be formed.

  Specific examples of the protective coating agent for forming the transparent protective coating film include a UV curable and thermosetting hard coating agent manufactured by Momentive Performance Materials, and a one-component room temperature curable hard coating manufactured by Nittobo. Examples thereof include a coating agent “SSG”.

  The film thickness of the transparent protective coating film is preferably 0.1 to 20 μm, and more preferably 0.1 to 10 μm. If the film thickness is less than 0.1 μm, the film thickness becomes too thin, and the performance as a transparent protective coating film (for example, scratch resistance, abrasion resistance, solvent resistance, etc.) may not be sufficiently exhibited. is there. On the other hand, when the thickness is more than 20 μm, when the transparent protective coating film contracts, the label (laminate) may largely warp toward the transparent protective coating film, which may make it difficult to use as a label. In addition, when the warped label is affixed to an object, particularly when it is affixed to a curved object, the label may peel off over time.

  The transparency of the transparent protective layer C is not limited as long as characters marked on the colored laser marking sheet layer D can be clearly observed, but the total light transmittance is preferably 80% or more.

[2-2] Colored laser marking sheet layer D:
The colored laser marking sheet layer D (hereinafter sometimes referred to as “colored laser marking sheet D”) includes a skin layer (c) and a core layer (c), and includes a skin layer (c) and a core layer ( The laminated structure is not particularly limited as long as it is a multilayer sheet containing c). For example, each of the skin layer (c) and the core layer (c) may have a single layer, and these may be arranged in a stacked state, or the skin layer (c) may be a first layer. It consists of a plurality of layers having a skin layer (c-1) and a second skin layer (c-2), and the first skin layer (c-1) is laminated on one surface side of the core layer (c). Arranged in a state where the second skin layer (c-2) is laminated on the other surface side (ie, the first skin layer (c-1) / core layer (c)) / Laminate comprising the second skin layer (c-2)).

  As described above, the skin layer (c) of the colored laser marking sheet D contains a transparent amorphous polyester-containing resin (2-4) containing a copolymerized amorphous polyester resin as a main component, The core layer (c) has an energy of 0.001 to 3 parts by mass with respect to 100 parts by mass of the transparent polycarbonate-containing resin (1-4) mainly composed of a polycarbonate resin and the polycarbonate-containing resin (1-4). It contains an absorbent and a coloring agent of 1 part by mass or more. Since the colored laser marking sheet D having such a configuration contains the energy absorber only in the core layer (c), the skin layer (c) is not marked. Therefore, there is an advantage that the smoothness of the surface (skin layer (c)) is excellent.

  The copolymerized amorphous polyester resin in the non-crystalline polyester-containing resin (2-4) contained in the skin layer (c) is a copolymer non-crystalline property in the non-crystalline polyester-containing resin (2-1). The thing similar to a polyester resin can be used in the same ratio.

  Moreover, the polycarbonate resin in the polycarbonate-containing resin (1-4) contained in the core layer (c) can be the same as the polycarbonate resin in the polycarbonate-containing resin (1-1) at the same ratio. . Moreover, the said coloring agent contained in this core layer (c) can use the thing similar to the coloring agent contained in the single colored sheet B mentioned above by the same compounding quantity.

  The compounding amount of the energy absorber in the colored laser marking sheet D is 0.001 to 3 parts by mass and 0.001 to 1 part by mass with respect to 100 parts by mass of the polycarbonate-containing resin (1-4). Is preferable, and it is still more preferable that it is 0.001-0.5 mass part. When the amount of the energy absorber is less than 0.001 part by mass, heat generation due to laser beam irradiation is small, so that sufficient contrast cannot be obtained. On the other hand, if it exceeds 3 parts by mass, the amount of energy absorbed by the laser beam becomes excessive, resulting in a decrease in contrast.

  The ratio of the thickness of the core layer (c) to the total thickness of the skin layer (c) and the core layer (c) needs to be 40 to 80%, and preferably 60 to 75%. When the ratio of the thickness of the core layer (c) is less than 40%, in addition to being inferior in laser colorability, strength and heat resistance are not sufficient. On the other hand, when it exceeds 80%, for example, when a laminate comprising the first skin layer (c-1) / core layer (c) / second skin layer (c-2) is molded, the core layer It becomes difficult to uniformly form the skin layers (c) (first skin layer (c-1) and second skin layer (c-2)) located on both sides of (c).

[2-3] Formation of thin laminate sheet for laser marking:
The thin laminate sheet for laser marking of this embodiment can be obtained by laminating by a conventionally known method. Specifically, when the transparent protective layer C is composed of a transparent laminate sheet, an acrylic adhesive is applied to one side of the transparent laminate sheet so as to have a thickness of 5 to 30 μm, and then acrylic adhesive is used. The colored laser marking sheet D is disposed on the surface side on which the agent is applied, and these can be obtained by pressurizing or heating and pressurizing and bonding them. The adhesive is not limited to the above acrylic adhesive, and various adhesives can be used. In addition to the acrylic adhesive, ethylene vinyl acetate is preferably used.

[3] Laser marking label:
The laser marking label of the present invention comprises the thin laminate sheet for laser marking of the present invention and an adhesive layer formed on one surface of the thin laminate sheet for laser marking. With such a structure, the outer surface layer is not removed by the laser beam, so that the appearance is not damaged during marking, the surface is smooth, and the anti-counterfeiting performance is excellent. The contrast of the printed part is good, and clear characters, symbols, images, etc. can be marked efficiently.

[3-1] Adhesive layer:
The adhesive layer is formed on one surface of the thin laminate sheet for laser marking. A label can be attached to the adherend by the adhesive layer.

  Examples of the material of the adhesive layer include acrylic, polyester, polyamide, styrene, and olefin adhesives. Among these, an acrylic pressure-sensitive adhesive is preferable from the viewpoint of excellent adhesiveness and versatility.

  Although there is no restriction | limiting in particular in the thickness of an adhesion layer, For example, it is preferable that it is 1-30 micrometers, and it is still more preferable that it is 5-20 micrometers.

  As described above, since the adhesive layer is for attaching a laser marking label comprising a thin laminate sheet for laser marking to an adherend, the lowermost layer (one of the thin laminate sheets for laser marking) Formed on the surface side).

  The label is generally commercialized with a release paper disposed on the adhesive layer. And when affixing a label to a to-be-adhered body, after peeling off this release paper from an adhesion layer, it affixes an adhesion layer to a to-be-adhered body, and is used. As the release paper, those used in conventional labels can be appropriately selected and used.

  The laser marking label of the present invention is produced, for example, after the thin layer laminate sheet for laser marking of the present invention is produced, and then on one side of the laminate sheet, that is, the colored sheet marking layer B or the colored laser marking sheet layer D side. An adhesive is applied to the surface to form an adhesive layer. Thereafter, a laser marking label is produced by attaching (laminating) release paper to the adhesive layer. In addition, application | coating of an adhesive and sticking (lamination) of release paper can be performed using the general purpose apparatus conventionally used.

[4] Laser marking method:
One embodiment of the laser marking method of the present invention is the transparent sheet side of the thin layered laminate sheet for laser marking provided in the laser marking label of the present invention, specifically, the transparent laser marking sheet layer A and the colored sheet layer B. In the laminated body consisting of the above, a laser beam is irradiated from the transparent protective layer C side and the laser marking label A is printed on the laminated body composed of the transparent laser marking sheet layer A side and the transparent protective layer C and the colored laser marking sheet layer D. According to such a method, the outer surface layer is not removed by the laser beam, that is, the appearance is not damaged at the time of marking. Therefore, the surface smoothness and the anti-counterfeiting performance are excellent, and the printed portion and the non-printed portion are not printed. The contrast of the portion is good, and clear characters, symbols, images, etc. can be marked efficiently.

Examples of the laser beam include gas lasers such as He—Ne laser, Ar laser, CO ₂ laser, and excimer laser, solid lasers such as YAG and YVO ₄ , semiconductor lasers, and dye lasers, but YAG, YVO _{4 and the} like. The solid laser is preferable.

  The laser beam may be single mode or multi-mode, and the beam diameter can be 20 to 100 μm. However, in the single mode, the beam diameter is 20 to 40 μm, and good print quality can be obtained. preferable.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples and a comparative example. In the following examples and comparative examples, “parts” and “%” mean parts by mass and mass% unless otherwise specified. In addition, various evaluations and measurements in Examples and Comparative Examples were performed by the following methods.

[1] Transparency of transparent sheet:
The total light transmittance of the transparent laser marking sheet A or the transparent protective layer C was measured using a spectrophotometer (trade name “EY7000” manufactured by Macbeth Co.). The measured value was evaluated according to the following criteria. Hereinafter, the transparent laser marking sheet A or the transparent protective layer C may be referred to as a transparent sheet.
A: Total light transmittance of 80% or more,
○: Total light transmittance of 60% or more and less than 80%,
X: The total light transmittance is less than 60%.

[2] Peel strength:
A release agent is applied to one end of a laminate sheet composed of a laser marking sheet layer and an auxiliary layer, sandwiched between two chrome-plated steel sheets, and then pressed at a press temperature of 80 ° C. using a vacuum press machine (manufactured by Nissei Plastic Industries). After preheating for ² seconds, it was held at 150 ° C. and an actual surface pressure of 12 kgf / cm ^{2 for} 90 seconds. Then, after cooling to room temperature, the laminate sheet was taken out and manually peeled off from the part where the release agent was applied. The heat-fusibility between the laminates at this time was evaluated according to the following criteria.
A: No peeling and excellent heat fusion property
○: A small part can be peeled but sheet destruction occurs (material destruction).
Δ: Peelable with a considerable force,
×: Whole surface peeling,
XX: Peeling after heating press or peeling of entire surface with very little force.

[3] Laser marking property:
About the laminated sheet for laser marking, laser marking property was evaluated using Nd · YVO ₄ laser (trade name “LT-100SA” manufactured by Laser Technology, trade name “RSM103D” manufactured by Lofincinal). Specifically, marking is performed on the laminate sheet for laser marking at a laser irradiation rate of 400 mm / second, the image clarity and the surface of the marking portion (printed portion) are visually observed, and evaluated according to the following criteria. did. The case where no color was developed is indicated by “XX”.
A: Excellent sharpness, no abnormalities such as blistering in the laser beam irradiation part,
○: Sharpness is good, there is no abnormality such as blistering of the laser beam irradiation part,
Δ: Insufficient sharpness or slight bulge in the laser beam irradiated part,
X: Vividness is poor or the swelling of the laser beam irradiation part is large.

[4] Contrast property:
While printing an image on the laser marking sheet layer, the above-mentioned [3] laser marking property process was performed on a part different from the printed part to mark the image. Then, the contrast of the image by laser marking and the contrast of the image by printing were evaluated visually. The evaluation criteria are shown below.
○: There is no change in the sharpness and visibility of the image by laser marking and the image by printing,
Δ: The sharpness and visibility of the image by laser marking and the image by printing are lowered.
X: The sharpness and visibility of the image by laser marking and the image by printing deteriorate.

[5] Abrasion resistance:
Evaluation was performed as follows using the laminate sheet for laser marking obtained in the above [4] evaluation of contrast. First, the marking part irradiated with the laser beam was rubbed with # 00 steel wool (load 500 g) 50 times (25 reciprocations) using a rubbing tester (Imoto Seisakusho), and the state before and after the test was visually evaluated. The evaluation criteria are shown below.
◎: Marking part is not abnormal, there is no change in image clarity and visibility,
○: Marking part is scraped, but image clarity and visibility are good.
Δ: Sharpening of the marking part is progressing, and the sharpness and visibility of the image are reduced.
X: The marking portion is greatly scraped, and the sharpness and visibility of the image are remarkably lowered.

(Example 1) A laminate comprising a single-layer transparent laser marking sheet A [1] / single-layer colored sheet B [1]:
First, a polycarbonate resin as the polycarbonate-containing resin (1-1) (trade name "TARFLON FN2500A" produced by Idemitsu Kosan Co., melt volume rate ⁼ 8 cm 3 / 10min) used, the polycarbonate-containing resin (1-1) To 100 parts of the laser beam 0.0015 part of carbon black (Mitsubishi Chemical # 10, average particle size 75 nm, DBP oil absorption 86 ml / 100 g) is blended as an energy absorber that absorbs water, and (n-octadecyl-3) as a phenol-based antioxidant 0.1 parts of-(3,5-di-t-butyl-4-hydroxyphenyl) propionate ("Irganox 1076" manufactured by Ciba Specialty Chemicals) and 2- (2 ' -Hydroxy-3 ', 5'-di-t-butylphenyl) -5 0.2 parts of chlorobenzotriazole (trade name “Tinuvin 327”, manufactured by Ciba Specialty Chemicals) and 0.1 part of “Rikestar EW-440A” manufactured by Riken Vitamin Co., Ltd. as a lubricant, A single layer transparent laser marking sheet A [1] is formed by mat processing so that the total thickness of the sheet is 50 μm and the average surface roughness (Ra) on both sides is 0.5 to 1.8 μm by T-die melt extrusion molding. It produced (it describes as "laser marking sheet A (1)" in Table 1).

  Next, an amorphous polyester resin (trade name “Easter GN071” manufactured by Eastman Chemical Co., EG / CHDM = 70/30 mol%) is used as the amorphous polyester-containing resin (2-2). 100 parts of polyester-containing resin (2-2) is blended with 0.3 parts by weight of calcium stearate and 5 parts of titanium oxide as a lubricant, and the total thickness of the sheet is 50 μm and the average surface roughness of both sides is obtained by T-die melt extrusion. Matting was performed so that (Ra) was 0.5 to 1.8 μm to produce a single-layer colored sheet B [1] (in Table 1 and Table 2, referred to as “colored sheet B (1)”). .

Next, the produced transparent laser marking sheet A [1] and the colored sheet B [1] are laminated to form a laminate, and then sandwiched between two chrome-plated steel plates, using a vacuum press machine (manufactured by Nissei Plastic Industry). After preheating for 90 seconds at a press temperature of 80 ° C., the substrate was held for 90 seconds at 150 ° C. and an actual surface pressure of 12 kgf / cm ² . Thereafter, after cooling to room temperature, a thin laminate sheet for laser marking was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Example 2) A laminate comprising a single-layer transparent laser marking sheet A [1] / single-layer colored sheet B [2]:
First, a polycarbonate resin and an amorphous polyester resin similar to those used in Example 1 were mixed at a mass ratio of 70/30 to obtain a resin alloy, and a phenolic antioxidant was added to 100 parts of the obtained resin alloy. As a lubricant, 0.1 part of (n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (“Irganox 1076” manufactured by Ciba Specialty Chemicals)) was used as a lubricant. Vitamin's “Rikestar EW-440A” was mixed with 0.1 part and 5 parts of titanium oxide, and the total thickness was 50 μm and the average surface roughness (Ra) on both sides was 0.00 by T-die melt extrusion. Matting was carried out so that the thickness became 5 to 1.8 μm to prepare a single-layer colored sheet B [2] (in Table 1, referred to as “colored sheet B (2)”).

  Next, a transparent laser marking sheet A [1] was prepared in the same manner as in Example 1, and the transparent laser marking sheet A [1] and the single-layer colored sheet B [2] thus prepared were used. Similarly, a thin laminate sheet for laser marking was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Example 3) Laminate comprising a single-layer transparent laser marking sheet A [1] / multi-layer colored sheet B [3]:
First, a multilayer composed of a skin layer (b) and a core layer (b) (skin layers (b) (first skin layer (b-1) and second skin layer (b -2)), a three-layer colored sheet B was prepared. That is, as the resin constituting the skin layer (b) (non-crystalline polyester-containing resin (2-3)), the same non-crystalline polyester resin as used in Example 1 was used. 100 parts of calcium stearate 0.3 parts by mass as a lubricant was blended to obtain a skin layer constituting material. Further, as the resin (polycarbonate-containing resin (1-3)) constituting the core layer (b), the same polycarbonate resin as that used in Example 1 was used, and phenolic antioxidant was added to 100 parts of this polycarbonate resin. As a lubricant, 0.1 part of (n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (“Irganox 1076” manufactured by Ciba Specialty Chemicals), Riken Vitamin The core layer constituent material was obtained by blending 0.1 part of “Riquester EW-440A” manufactured by the company and 10 parts of titanium oxide, and then by T-die melt extrusion using the skin layer constituent material and the core layer constituent material. The total thickness is 50 μm (first skin layer (b-1) (10 μm) / core layer (b) (30 μm) / second skin layer (b-1) (1 μm) layer structure (core layer (b) thickness ratio 60%)), and mat processing is performed so that the average surface roughness (Ra) of both surfaces is 0.5 to 1.8 μm. Sheet B [3] was prepared (in Table 1, referred to as “colored sheet B (3)”).

  Next, a transparent laser marking sheet A [1] was produced in the same manner as in Example 1, and Example 1 was used using the produced transparent laser marking sheet A [1] and the multilayer colored sheet B [3]. Similarly, a thin laminate sheet for laser marking was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Example 4) Laminated body composed of multilayer transparent laser marking sheet A [2] / single-layer colored sheet B [1]:
First, a multilayer composed of a skin layer (a) and a core layer (a) (skin layers (a) (first skin layer (a-1), second skin layer (a 2)) A transparent laser marking sheet A having 3 layers) was prepared. That is, the non-crystalline polyester resin similar to that used in Example 1 was used as the resin constituting the skin layer (a) (non-crystalline polyester-containing resin (2-1)). To 100 parts, 0.3 parts by mass of calcium stearate as a lubricant was blended to obtain a core layer constituting material.

  Further, as the resin constituting the core layer (a) (polycarbonate-containing resin (1-2)), the same polycarbonate resin as that used in Example 1 is used, and 100 parts of this polycarbonate resin absorbs laser light. Carbon black (Mitsubishi Chemical # 10, average particle diameter 75 nm, DBP oil absorption 86 ml / 100 g) is blended in 0.0015 parts by mass as an absorber, and (n-octadecyl-3- ( 0.1 part of 3,5-di-t-butyl-4-hydroxyphenyl) propionate ("Irganox 1076" manufactured by Ciba Specialty Chemicals) and 2- (2'-hydroxy) as an ultraviolet absorber -3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole (trade name “Thi Bin 327 ", manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.2 parts, and as a lubricant, Riken Vitamin Co., Ltd." Rikester EW-440A "0.1 parts was blended to obtain a core layer constituent material. Then, using the skin layer constituting material and the core layer constituting material, the skin layers (a) (first skin layer (a-1), second skin) of the front and back surfaces of the core layer (a) are formed by T-die melt extrusion molding. The thickness of the skin layer (a-2)) is the same, and the total thickness of the sheet is 50 μm (first skin layer (a-1) (9 μm) / core layer (a) (32 μm) / second skin. The layer structure of layer (a) (9 μm) (the thickness ratio of core layer (a) is 64%)), and mat processing is performed so that the average surface roughness (Ra) of both surfaces is 0.5 to 1.8 μm. Thus, a multi-layer transparent laser marking sheet A [2] was prepared (in Table 1, “Laser marker”). Referred to as the King sheet A (2) ").

  Next, a single-layer colored sheet B [1] was produced in the same manner as in Example 1, and the produced single-layer colored sheet B [1] and the multilayer transparent laser marking sheet A [2] were used. A thin laminate sheet for laser marking was obtained in the same manner as in Example 1 (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Example 5) Laminate comprising transparent protective layer C (transparent laminate sheet) / multilayer colored laser marking sheet D [1]:
First, a multilayer composed of a skin layer (c) and a core layer (c) (skin layers (c) (first skin layer (c) and second skin layer (c)) on both sides of the core layer (c), respectively) 3 layers) colored laser marking sheet D was prepared. That is, as the resin constituting the skin layer (c) (non-crystalline polyester-containing resin (2-4)), the same non-crystalline polyester resin as used in Example 1 was used. To 100 parts, 0.3 parts by mass of calcium stearate as a lubricant was blended to obtain a skin layer constituting material.

  Further, as the resin constituting the core layer (c) (polycarbonate-containing resin (1-4)), the same polycarbonate resin as that used in Example 1 is used, and 100 parts of this polycarbonate resin absorbs laser light. Carbon black (Mitsubishi Chemical # 10, average particle size 75 nm, DBP oil absorption 86 ml / 100 g) is blended in 0.004 parts by mass as an absorber, and (n-octadecyl-3- ( “RIQUESTER EW-440A” manufactured by Riken Vitamin Co., Ltd. using 0.1 part of 3,5-di-t-butyl-4-hydroxyphenyl) propionate (“Irganox 1076” manufactured by Ciba Specialty Chemicals) as a lubricant. 0.3 parts and 10 parts of titanium oxide were blended to obtain a core layer constituent material. The skin layer constituting material and the core layer constituting material have the same thickness of the skin layers (c) (first skin layer (c), second skin layer (c)) of the front and back surfaces of the core layer (c). The total thickness of the sheet is 50 μm (layer configuration of the first skin layer (c) (9 μm) / core layer (c) (32 μm) / second skin layer (c) (9 μm) (core layer (c) And a matte processing so that the average surface roughness (Ra) of both surfaces is 0.5 to 1.8 μm to produce a multi-layer colored laser marking sheet D [1] ( In Table 1, it is described as “laser marking sheet D (1)”).

  Next, as a transparent protective layer C, a PET laminate film (thickness 50 μm, described as “laminate sheet C” in Tables 1 and 2) manufactured by Tokyo Laminex Co., Ltd., and a multilayered colored laser marking sheet D [1] thus produced were used. The thin-layer laminate sheet for laser marking was obtained in the same manner as in Example 1 (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Example 6) Laminated body composed of transparent protective layer C (transparent protective coat film) / multilayer colored laser marking sheet D [1]:
First, in the same manner as in Example 5, a multilayer colored laser marking sheet D [1] was produced. Next, instead of the PET laminate film of Example 5, a UV curable hard coat agent “UVHC7000” manufactured by Momentive Performance Materials Co., Ltd. was used so that the film thickness after drying and curing was 4 to 5 μm. After applying to the colored laser marking sheet D [1], it was cured at 5 KJ / m ² in a nitrogen atmosphere to form a transparent protective coating film (indicated as “coat layer C” in Table 1). In this way, a thin laminate sheet for laser marking was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 1.

(Comparative Example 1) Laminated body composed of multi-layer transparent laser marking sheet A [3] / single-layer colored sheet B [1]:
First, a multi-layered transparent laser marking sheet A [3] composed of a skin layer and a core layer (three layers each having a skin layer disposed on both sides of the core layer) was produced. That is, as the resin constituting the skin layer, the same amorphous polyester resin as used in Example 1 was used, and 100 parts of this amorphous polyester resin was mixed with 0.3 part of calcium stearate as a lubricant. A skin layer constituting material was obtained.

  Further, as the resin constituting the core layer, the same polycarbonate resin as that used in Example 1 was used, and 100 parts of the polycarbonate resin was carbon black (Mitsubishi Chemical # 10, average particle as an energy absorber that absorbs laser light). (Diameter 75 nm, DBP oil absorption 86 ml / 100 g) 0.0015 parts by mass and as a phenolic antioxidant (n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate ("Irganox 1076" manufactured by Ciba Specialty Chemicals) 0.1 part, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chloro as an ultraviolet absorber Benzotriazole (trade name “Tinubin 327”, manufactured by Ciba Specialty Chemicals) Parts and, as a lubricant, Riken Vitamin Co., Ltd. "Rikesuta EW-440A" 0.1 parts by blending, to obtain a core layer-forming material.

  Thereafter, the skin layer material and the core layer material were subjected to T-die melt extrusion, and the thickness of the skin layers on the front and back of the core layer was the same, and the total thickness of the sheet was 50 μm (skin layer (17 μm) / core layer (16 μm) / skin layer (17 μm) layer structure (core layer thickness ratio 32%)), and mat processing is performed so that the average surface roughness (Ra) of both surfaces is 0.5 to 1.8 μm. A multi-layer transparent laser marking sheet A [3] was prepared (indicated as “laser marking sheet A (3)” in Table 2).

  Next, a single-layer colored sheet B [1] was produced in the same manner as in Example 1, and the produced single-layer colored sheet B [1] and the multilayer transparent laser marking sheet A [3] were used. A thin laminate sheet for laser marking was obtained in the same manner as in Example 1 (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 2.

(Comparative Example 2) Laminate comprising transparent protective layer C / multilayer colored laser marking sheet D [2]:
First, a multilayer laser marking sheet D composed of a skin layer and a core layer (three layers each having a skin layer disposed on both sides of the core layer) was prepared. That is, as the resin constituting the skin layer, the same amorphous polyester resin as used in Example 1 was used, and 100 parts of this amorphous polyester resin was mixed with 0.3 part of calcium stearate as a lubricant. A skin layer constituting material was obtained.

  Further, as the resin constituting the core layer, the same polycarbonate resin as that used in Example 1 was used, and 100 parts of this polycarbonate resin was subjected to (n-octadecyl-3- (3,5) as a phenolic antioxidant. -Di-t-butyl-4-hydroxyphenyl) propionate ("Irganox 1076" manufactured by Ciba Specialty Chemicals) 0.1 parts, "Rikestar EW-440A" 0.1 parts manufactured by Riken Vitamin Co., Ltd. as a lubricant Then, 10 parts of titanium oxide was blended to obtain a core layer constituent material, and then the skin layer constituent material and the core layer constituent material were the same in the thickness of the skin layers on the front and back of the core layer, The thickness is 50 μm (skin layer (3 μm) / core layer (44 μm) / skin layer (3 μm) layer structure (core layer thickness ratio 88%)). Matt processing was performed so that the surface roughness (Ra) was 0.5 to 0.8 μm, and a multilayer colored laser marking sheet D [2] was prepared (in Table 2, “laser marking sheet D (2)”). Write down).

  Next, as a transparent protective layer C, a thin film layer for laser marking was used in the same manner as in Example 1, using a PET laminate film (thickness 50 μm) manufactured by Tokyo Laminex, and the multilayered colored laser marking sheet D [2] produced. A laminate sheet was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 2.

(Comparative Example 3) Laminated body comprising transparent protective layer C / multilayer colored laser marking sheet D [3]:
First, a multilayer laser marking sheet D composed of a skin layer and a core layer (three layers each having a skin layer disposed on both sides of the core layer) was prepared. That is, as the resin constituting the skin layer, the same amorphous polyester resin as used in Example 1 was used, and 100 parts of this amorphous polyester resin was mixed with 0.3 part of calcium stearate as a lubricant. A skin layer constituting material was obtained.

  Further, as the resin constituting the core layer, the same polycarbonate resin as that used in Example 1 was used, and 100 parts of this polycarbonate resin was subjected to (n-octadecyl-3- (3,5) as a phenolic antioxidant. -Di-t-butyl-4-hydroxyphenyl) propionate ("Irganox 1076" manufactured by Ciba Specialty Chemicals) 0.1 parts, "Rikestar EW-440A" 0.1 parts manufactured by Riken Vitamin Co., Ltd. as a lubricant Then, 10 parts of titanium oxide was blended to obtain a core layer constituent material, and then the skin layer constituent material and the core layer constituent material were the same in the thickness of the skin layers on the front and back of the core layer, The thickness is 50 μm (skin layer (20 μm) / core layer (10 μm) / skin layer (20 μm) layer structure (core layer thickness ratio 20%)), both sides Matt processing was performed so that the average surface roughness (Ra) was 0.5 to 1.8 μm to produce a multi-layer colored laser marking sheet D [3] (in Table 2, “laser marking sheet D (3)”) ).

  Next, as a transparent protective layer C, a thin film layer for laser marking was used in the same manner as in Example 1 using a PET laminate film (thickness 50 μm) manufactured by Tokyo Laminex, and the multilayered colored laser marking sheet D [3] produced. A laminate sheet was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 2.

(Comparative Example 4) Laminated body comprising transparent protective layer C / single-layer colored sheet B [1]:
Laser marking in the same manner as in Example 1 using a PET laminate film (thickness 50 μm) manufactured by Tokyo Laminex as a transparent protective layer C and a single-layer colored sheet B [1] produced in the same manner as in Example 1. A thin-layer laminate sheet was obtained (sheet thickness 100 μm). Each said evaluation was performed about the obtained thin layer laminated sheet for laser marking. The evaluation results are shown in Table 2.

  As is clear from Table 1 and Table 2, the sheets of Examples 1 to 5 are superior to the sheets of Comparative Examples 1 to 4, respectively, in terms of sheet transparency and adhesion between the two layers after lamination, and It has excellent laser marking properties and abrasion resistance of the marking portion.

  In addition, although the sheet | seat of Example 5 is a little inferior in laser marking property compared with the sheet | seat of Examples 1-4, when it uses as a label for laser marking, it fully responds to the request | requirement as a label. The wear resistance was the best.

  The sheets of Examples 1 to 4 are excellent in laser marking properties. Here, although it is a little inferior in abrasion resistance as compared with the sheet of Example 5, when used as a label for laser marking, it can sufficiently satisfy the demand as a label.

  Therefore, the thin laminate sheet for laser marking of the present invention is capable of preventing counterfeiting and tampering while ensuring productivity even when used as a label for laser marking. It was confirmed that it was able to sufficiently meet market demands.

  On the other hand, the sheet of Comparative Example 1 was inferior in laser marking properties and inferior in contrast properties because the thickness ratio of the marking layer of the transparent laser marking sheet A [3] was 32%.

  Since the sheet of Comparative Example 2 has a thin skin layer of the multilayer colored laser marking sheet D [2] (that is, the core layer is thick (core layer thickness ratio 80%)), the adhesiveness to the transparent protective layer C Was insufficient. Therefore, blisters were generated due to heat generation during laser beam irradiation.

  The sheet of Comparative Example 3 was inferior in laser marking property because the core layer of the multilayer colored laser marking sheet D [3] was thin.

  In the sheet of Comparative Example 4, neither the transparent protective layer C nor the single-layer colored sheet B [1] had laser marking performance, did not develop color at all, and laser marking was impossible.

  The thin-layer laminate sheet for laser marking of the present invention is a thin film (total thickness less than 150 μm), has excellent laser marking properties, and has high contrast between a printed portion and a non-printed portion, and has clear characters, symbols, An image is obtained. Moreover, since the adhesiveness between lamination | stacking is excellent, the blister resulting from the heat_generation | fever of the irradiation part of a laser beam is hard to generate | occur | produce. Furthermore, it has heat resistance, bendability, and wear resistance, and is particularly excellent in prevention of tampering and forgery and can be suitably used as a material for a label for laser marking. The laser marking label of the present invention can be used as a label displaying production lots and the like used in almost every field of industry. The laser marking method of the present invention can be employed as a marking method for a label for laser marking on which a production lot or the like is displayed.

Claims (6)

A laser marking sheet layer and a transparent or colored auxiliary layer disposed on one surface of the laser marking sheet layer, and a thin layered laminate sheet for laser marking comprising a laminate having a thickness of 150 μm or less, ,
The laminate is composed of a transparent laser marking sheet layer A and a colored sheet layer B, or a transparent protective layer C and a colored laser marking sheet layer D,
The transparent laser marking sheet layer A is a single layer or a multilayer having a thickness of 30 to 80 μm,
The single layer of the transparent laser marking sheet layer A has a ratio of 0.1 to 100 parts by mass of the transparent polycarbonate-containing resin (1-1) having a polycarbonate resin as a main component and the polycarbonate-containing resin (1-1). It consists of a transparent sheet containing 0005 to 1 part by mass of an energy absorber,
The multilayer transparent laser marking sheet layer A is a transparent sheet including a skin layer (a) and a core layer (a),
The skin layer (a) includes a structural unit (A-1) derived from terephthalic acid, a structural unit (A-2) derived from ethylene glycol, and a structural unit derived from 1,4-cyclohexanedimethanol (A -3), the content ratio of the structural unit (A-2) derived from ethylene glycol and the structural unit (A-3) derived from 1,4-cyclohexanedimethanol ((A-2) / ( A-3)) contains a transparent amorphous polyester-containing resin (2-1) based on a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70,
The said core layer (a) is 0.0005-1 mass with respect to 100 mass parts of transparent polycarbonate containing resin (1-2) which has a polycarbonate resin as a main component, and the said polycarbonate containing resin (1-2). The ratio of the thickness of the core layer (a) to the total thickness of the skin layer (a) and the core layer (a) is 40 to 80%.
The colored sheet layer B is a single layer or a multilayer having a thickness of 30 to 80 μm,
The single colored sheet layer B is a structural unit derived from terephthalic acid (B-1), a structural unit derived from ethylene glycol (B-2), and a structural unit derived from 1,4-cyclohexanedimethanol. The content ratio ((B-2) of the structural unit (B-3) which contains (B-3) and is derived from the ethylene glycol and the structural unit (B-3) derived from the 1,4-cyclohexanedimethanol. / (B-3)) is a transparent amorphous polyester-containing resin (2-2) mainly composed of a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70, and It consists of a sheet containing 1 part by mass or more of a colorant with respect to 100 parts by mass of the crystalline polyester-containing resin (2-2),
The multilayer colored sheet layer B is a sheet including a skin layer (b) and a core layer (b),
The skin layer (b) is composed of a structural unit (C-1) derived from terephthalic acid, a structural unit (C-2) derived from ethylene glycol, and a structural unit derived from 1,4-cyclohexanedimethanol (C -3), the content ratio of the structural unit (C-2) derived from ethylene glycol and the structural unit (C-3) derived from 1,4-cyclohexanedimethanol ((C-2) / ( C-3)) contains a transparent amorphous polyester-containing resin (2-3) mainly comprising a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70,
The core layer (b) is colored in an amount of 1 part by mass or more with respect to 100 parts by mass of the transparent polycarbonate-containing resin (1-3) mainly composed of a polycarbonate resin and the polycarbonate-containing resin (1-3). The ratio of the thickness of the core layer (b) to the total thickness of the skin layer (b) and the core layer (b) is 40 to 80%.
The transparent protective layer C is a single layer or a multilayer that protects one surface of the colored laser marking sheet layer D,
The colored laser marking sheet layer D includes a skin layer (c) and a core layer (c),
The skin layer (c) is composed of a structural unit (D-1) derived from terephthalic acid, a structural unit (D-2) derived from ethylene glycol, and a structural unit derived from 1,4-cyclohexanedimethanol (D -3), the content ratio of the structural unit (D-2) derived from ethylene glycol and the structural unit (D-3) derived from 1,4-cyclohexanedimethanol ((D-2) / ( D-3)) contains a transparent amorphous polyester-containing resin (2-4) based on a copolymerized amorphous polyester resin having a molar ratio of 90/10 to 30/70,
The core layer (c) is 0.001 to 3 parts by mass with respect to 100 parts by mass of the transparent polycarbonate-containing resin (1-4) having the polycarbonate resin as a main component and the polycarbonate-containing resin (1-4). The ratio of the thickness of the said core layer (c) with respect to the total thickness of the said skin layer (c) and the said core layer (c) which contains an energy absorber and 1 mass part or more of coloring agents is 40-. A thin layered sheet for laser marking that is 80%. The single transparent laser marking sheet layer A is 0.01 to 3 parts by mass of a lubricant, 0.1 to 5 parts by mass of an antioxidant with respect to 100 parts by mass of the polycarbonate-containing resin (1-1). It further contains at least one selected from the group consisting of 0.1 to 5 parts by weight of an anti-coloring agent, 0.1 to 5 parts by weight of an ultraviolet absorber, and 0.1 to 5 parts by weight of a light stabilizer. And
In the skin layer (a), the multilayer transparent laser marking sheet layer A comprises 0.01 to 3 parts by mass of a lubricant with respect to 100 parts by mass of the amorphous polyester-containing resin (2-1). 0.1 to 5 parts by weight of antioxidant, 0.1 to 5 parts by weight of coloring inhibitor, 0.1 to 5 parts by weight of UV absorber, and 0.1 to 5 parts by weight of light stabilizer. At least one selected from the group, or 0.01 to 3 parts by mass of a lubricant in the core layer (a) with respect to 100 parts by mass of the polycarbonate-containing resin (1-2); 1-5 parts by weight of antioxidant, 0.1-5 parts by weight of coloring inhibitor, 0.1-5 parts by weight of UV absorber, and 0.1-5 parts by weight of light stabilizer Or at least one selected from the above, or in the skin layer (a), 0.01 to 3 parts by mass of lubricant, 0.1 to 5 parts by mass of antioxidant, and 0.1 to 5 parts by mass of anti-coloring agent for 100 parts by mass of crystalline polyester-containing resin (2-1) And further containing at least one selected from the group consisting of 0.1 to 5 parts by mass of an ultraviolet absorber and 0.1 to 5 parts by mass of a light stabilizer, and in the core layer (a), For 100 parts by mass of the polycarbonate-containing resin (1-2), 0.01 to 3 parts by mass of a lubricant, 0.1 to 5 parts by mass of an antioxidant, 0.1 to 5 parts by mass of an anti-coloring agent, The thin layered laminate for laser marking according to claim 1, further comprising at least one selected from the group consisting of 0.1 to 5 parts by weight of an ultraviolet absorber and 0.1 to 5 parts by weight of a light stabilizer. Body sheet.   The transparent protective layer C is composed of a transparent laminate sheet or a transparent protective coat, and the transparent laminate sheet and the colored laser marking sheet layer D are bonded to each other with ethylene vinyl acetate or an acrylic adhesive. 3. A thin-layer laminate sheet for laser marking according to 1 or 2.   The laser marking according to any one of claims 1 to 3, wherein the energy absorbent contained in the laminate is carbon black having an average particle diameter of 1 to 120 nm and a dibutyl phthalate oil absorption of 60 to 170 ml / 100 g. Thin layer laminate sheet.   A laser marking label comprising: the thin layered laminate sheet for laser marking according to any one of claims 1 to 4; and an adhesive layer formed on one surface of the thin layered laminate sheet for laser marking.   A laser beam is applied to the laser marking label from the transparent laser marking sheet layer A or the transparent protective layer C side of the laminar laminate sheet for laser marking provided in the laser marking label according to claim 5. Laser marking method for printing.