JP2006256308A - Laminate for laser marking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate for laser marking useful as a means for applying display, for example, to the surface of a sheetlike molded product comprising a thermoplastic resin by skillfully utilizing a thermoplastic polymer composition for laser marking, improved in its slip properties in a manufacturing process and solved in its blocking problem when stored by a sheet-fed system. <P>SOLUTION: In the laminate for laser marking comprising laminating a B-layer at least on one side of an A-layer, the A-layer is a layer which is marked by at least two different hues by irradiating the A-layer with at least two laser beams having different energies and formed from the thermoplastic polymer composition for multicolor forming laser marking which satisfies (1) a chromatic colorant, a black substance disappearing or discoloring upon the reception of a laser beam and a thermoplastic polymer are contained in the following ratio and (2) the content of the chromatic colorant is 0.001-3 pts.wt. and the content of the black substance is 0.01-2 pts.wt. per 100 pts.wt. of the thermoplastic polymer and the B-layer is formed from a transparent thermoplastic resin and the light transmittance thereof as a single layer is 70% or above. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminate for laser marking.

  Conventionally, for example, when displaying (characters, figures, symbols, combinations thereof, etc.) on the surface of a thermoplastic resin sheet-like molded product such as a prepaid card, printing means such as silk printing is employed. However, in the case of using printing means, it is necessary to create a plate for each display. Therefore, the cost is high and a long production time is required. In addition, defective products caused by plate displacement or printing ink bleeding at the time of printing. Has a serious drawback in that it is difficult to recycle and must be discarded.

  On the other hand, recently, a thermoplastic polymer composition for laser marking has been proposed, in which multicolor marking can be applied to the resin surface by laser light irradiation. In particular, in recent years, techniques for diversifying the color of marking have also been developed. For example, a laser beam is applied to a molded article containing a substance that changes color or loses its color due to absorption of laser light and a dye substance that is not easily affected by laser light. There is also proposed a method of irradiating (see Patent Documents 1 and 2). Then, a so-called thick product such as a household product, an electrical product, or an OA device is molded from the thermoplastic polymer composition for laser marking, and a display is imprinted on the surface of the product by a laser marking device.

JP-A-6-297828 JP-A-8-127175

  An object of the present invention is to provide a laser marking laminate useful as a means for displaying on the surface of a thermoplastic resin sheet-shaped molded article by skillfully using a thermoplastic polymer composition for laser marking, for example. It is in.

  As a result of repeated studies, the inventors of the present invention have made a transparent thermoplastic resin as a welding means if a laser marking thermoplastic polymer composition and a transparent thermoplastic resin are laminated to form a laminate for laser marking. Since it can be utilized, the present inventors have come up with the idea that the above-mentioned laminate with the marking can be easily attached to the surface of a thermoplastic resin sheet-like molded product.

  The present invention has been completed based on the above idea, and the gist thereof is a laminate for laser marking in which a B layer is laminated on at least one side of an A layer, and the A layer has different energy. It was formed with a thermoplastic polymer composition for multicolor laser marking that satisfies the following (1) and (2), which is marked in two or more different color tones by irradiating two or more laser beams having The layer B is a laminate for laser marking, which is formed of a transparent thermoplastic resin and has a light transmittance of 70% or more in a single layer.

(1) A chromatic colorant, a black substance that disappears or discolors itself by receiving laser light, and a thermoplastic polymer are contained in the following proportions.
(2) When the thermoplastic polymer is 100 parts by weight, 0.001 to 3 parts by weight of the chromatic colorant and 0.01 to 2 parts by weight of the black substance are contained.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body for laser markings useful as a means to display on the surface of the sheet-like molded article of a thermoplastic resin, for example can be provided.

  Hereinafter, the present invention will be described in detail. In the laminate for laser marking of the present invention (hereinafter simply referred to as a laminate), the B layer is laminated on at least one surface of the A layer, and the A layer is irradiated with two or more laser beams having different energies. Is formed with a specific multicolor laser marking thermoplastic polymer composition (a) marked in two or more different color tones, and the B layer is transparent with a light transmittance of 70% or more in a single layer It is formed with a thermoplastic resin (b).

<Thermoplastic polymer composition for multicolor laser marking (a)>
In the present invention, the thermoplastic polymer composition for multicolor laser marking (a) is a thermoplastic polymer composition that is marked in two or more different colors by irradiating two or more laser beams having different energies. Point to.

  In the present invention, the thermoplastic polymer composition (a) includes a chromatic colorant, a black substance that disappears or changes its color when receiving laser light, and a thermoplastic polymer. The content of the chromatic colorant is 0.001 to 3 parts by weight when the thermoplastic polymer is 100 parts by weight, and the content of the black substance is 100 parts by weight of the thermoplastic polymer. When used, a thermoplastic polymer composition of 0.01 to 2 parts by weight is used.

  The color development mechanism of the multicolor laser marking by the thermoplastic polymer composition (a) has not been clarified, but is generally presumed to be based on the following phenomenon. The color development mechanism of the multicolor laser marking according to the present invention is not limited to the following mechanism.

  When the laminate of the present invention containing the above thermoplastic polymer composition (a) in one layer is irradiated with laser light, depending on the energy of the laser light, degradation of the chromatic colorant, such as disappearance of the black material, discoloration, Spattering occurs. Here, in the portion where the vaporization or discoloration of the black material is generated, the color of the material other than the black material appears stronger than the portion where the black material is relatively not generated. Furthermore, the portion where the chromatic colorant is decomposed, scattered or the like becomes a color having a lower density of the color derived from the chromatic colorant or white than the portion where the chromatic colorant is not generated. Since the degree of color change varies depending on the difference in energy of the irradiated laser beam, it is considered that marking is performed in two or more different color tones by irradiating two or more laser beams having different energies. In addition, the chromatic colorant in the present invention usually causes decomposition, scattering, etc. at a higher energy than the energy that vaporizes, discolors, and the like of the black substance.For example, for a molded product exhibiting a black or dark background color, When irradiated with low-energy laser light, the irradiated portion develops a color in which the influence of the substance derived from the chromatic colorant appears strongly (hereinafter also simply referred to as “color derived from the chromatic colorant”). When a high-energy laser beam is irradiated, it is possible to obtain each marking in which the irradiated portion is colored in a color having a reduced color density derived from the chromatic colorant. As described above, it is considered that marking can be performed in two or more different color tones other than the black or dark color which is the color (ground color) of the unirradiated portion of the laser light.

1. Chromatic colorant for multicolor laser marking:
The chromatic colorant in the present invention may be any colorant as long as it does not interfere with the excellent performance of the multicolor laser marking in the present invention, but the colorant is 360 ° C. or higher and 590 ° C. by differential thermal analysis. It has an exothermic peak in the following range. The lower limit temperature of the exothermic peak range is more preferably 380 ° C, particularly preferably 400 ° C, and the upper limit temperature is more preferably 585 ° C. If the temperature is too low, the color marking derived from the chromatic colorant tends to become unclear when irradiated with low energy laser light. On the other hand, if the temperature is too high, the marking of the color having a lowered color density derived from the chromatic colorant tends to become unclear when irradiated with high energy laser light. The measurement conditions for differential thermal analysis are as described in the reference examples.

  The chromatic colorant in the present invention may be any substance as long as the exothermic peak by differential thermal analysis is in the above-mentioned temperature range, and laser marking of two or more different colors can be performed on the laminate of the present invention by laser light irradiation. . Moreover, if the range of the exothermic peak is in the above range, two or more chromatic colorants may be used in combination. The color of the chromatic colorant in the present invention may be any color such as red, yellow, blue, purple, and green as long as it is other than black and white. A pigment or a dye may be used.

  Examples of chromatic colorants whose exothermic peaks by differential thermal analysis are in the above temperature range are shown below. An example of the color of each colorant is shown in parentheses. Pigment or dye having a phthalocyanine skeleton (blue to green), pigment or dye having a diketopyrrolopyrrole skeleton (orange to red), pigment or dye having a dioxazine skeleton (purple), pigment or dye having a quinacridone skeleton (orange to Purple), pigment or dye having a quinophthalone skeleton (yellow to red), pigment or dye having anthraquinone skeleton (yellow to blue), pigment or dye having a perylene skeleton (red to purple), pigment or dye having a perinone skeleton (Orange to red), pigment or dye having a metal complex skeleton (yellow to purple), indanthrone pigment (blue to green), triallyl carbonium pigment (blue), monoazo pigment (yellow to green), Disazo pigments (yellow to green), isoindolinone pigments (yellow to purple), thioindigo pigments (red to purple), anthrapyridone dyes ( Color), and the like. Among these, the composition (molded article) has at least one skeleton selected from a phthalocyanine skeleton, a diketopyrrolopyrrole skeleton, a dioxazine skeleton, a quinacridone skeleton, a quinophthalone skeleton, an anthraquinone skeleton, a perylene skeleton, a metal complex skeleton, and the like. When a chromatic colorant is included, markings of two or more different tones including a color derived from the chromatic colorant are clearly formed on the surface of a composition (molded product) that exhibits a black or dark ground color. This is preferable because it can be performed. Among them, chromatic colorants having at least one skeleton selected from a phthalocyanine skeleton, a diketopyrrolopyrrole skeleton, a dioxazine skeleton, a quinacridone skeleton, a quinophthalone skeleton, a perylene skeleton, and a metal complex skeleton are more preferable, and a phthalocyanine skeleton, a diketo A chromatic colorant having at least one skeleton selected from a pyrrolopyrrole skeleton and a dioxazine skeleton is particularly preferable. Specific examples are given below.

1-1. Chromatic colorant having a phthalocyanine skeleton:
Examples of the chromatic colorant having the phthalocyanine skeleton include compounds represented by the following general formula (1).

  The chromatic colorant having the phthalocyanine skeleton is a pigment or a dye. In the above general formula (1), M is preferably copper (Cu), aluminum (Al), zinc (Zn), tin (Sn) or two hydrogen atoms, copper (Cu), aluminum (Al). Alternatively, zinc (Zn) is more preferable, and copper (Cu) or aluminum (Al) is particularly preferable. In addition, when M is a metal, you may have ligands, such as a halogen atom and OH.

In the general formula ^{(1), R} 1 ~R ¹⁶ is a hydrogen atom; a fluorine, chlorine, bromine, halogen atom such as iodine; sulfonic acid amide group _{(-SO 2 NHR), - SO} 3 - · NH 3 A substituent such as R ⁺ (wherein R is an alkyl group having 1 to 20 carbon atoms) is preferable, and a plurality of adjacent Rs out of R ^{1 to} R ¹⁶ are connected to form an aromatic ring. Groups are also preferred. Particularly preferred is a hydrogen atom or a sulfonic acid amide group.

  As the chromatic colorant having the phthalocyanine skeleton, preferred specific structures are listed in the following (1) to (6). Of these, (1), (3) and (4) are particularly preferred.

(1) A copper phthalocyanine pigment in which M in the general formula (1) is Cu and R ^{1 to} R ¹⁶ are hydrogen atoms (the following formula (2)).

The crystal of the copper phthalocyanine pigment may be α type or β type. The average secondary particle diameter of the β-type copper phthalocyanine pigment is generally more than 20 μm and not more than 30 μm. In the present invention, the upper limit is preferably 20 μm, more preferably 10 μm, and the lower limit is 1 μm. . The average secondary particle size can be confirmed with a laser scattering particle size distribution measuring device or the like.

(2) A halogen-containing copper phthalocyanine pigment in which M in the general formula (1) is Cu, and R ^{1 to} R ¹⁶ are each independently a hydrogen atom or a halogen atom. The halogen atom is preferably a chlorine atom or a bromine atom.

(3) M in the general formula (1) is Cu, and 4 to 8, preferably 4 of R ^{1 to} R ¹⁶ are the sulfonic acid amide group or —SO ₃ — · NH ₃ R described above. ⁺ , A solvent-soluble copper phthalocyanine dye, preferably a sulfonic acid amide. The structure of a particularly preferred solvent-soluble copper phthalocyanine dye is shown in the following general formula (3).

In the general formula (3), it is particularly preferable that each R is independently an alkyl group having 4 to 8 carbon atoms.

(4) An aluminum phthalocyanine pigment in which M in the above general formula (1) is Al and R ^{1 to} R ¹⁶ are hydrogen atoms. Al preferably has —OH or —Cl as a ligand, and more preferably has —OH. A particularly preferred aluminum phthalocyanine pigment structure is shown in the following formula (4).

(5) A tin phthalocyanine pigment in which M in the general formula (1) is Sn, and R ^{1 to} R ¹⁶ are each independently a hydrogen atom or a halogen atom.

(6) A zinc phthalocyanine pigment in which M in the general formula (1) is Zn, and R ^{1 to} R ¹⁶ are each independently a hydrogen atom or a halogen atom. The structure of the zinc phthalocyanine pigment is shown in the following general formula (5).

As the zinc phthalocyanine pigment, a zinc phthalocyanine pigment in which R ^{1 to} R ¹⁶ in the general formula (5) are all hydrogen atoms is particularly preferable.

1-2. Chromatic colorant having a diketopyrrolopyrrole skeleton:
Examples of the chromatic colorant having a diketopyrrolopyrrole skeleton include compounds represented by the following general formula (6), and the colorant is usually a pigment.

The aromatic ring constituting Ar and Ar ′ may be any ring as long as it has aromaticity, but is usually an aromatic ring consisting of a 5- or 6-membered monocyclic ring or a 2-6 condensed ring. Yes, it may contain heteroatoms such as O, S, N and the like. Specifically, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, pyridine ring, thiophene ring, pyrrole ring, furan ring, benzothiophene ring, benzofuran ring, benzopyrrole ring, imidazole ring, quinoline ring, isoquinoline A ring, a carbazole ring, a thiazole ring, a dibenzothiophene ring, and the like. Among these, a 6-membered ring is preferable, a 6-membered single ring is more preferable, and a benzene ring is particularly preferable.

The aromatic ring preferably has a substituent, and preferred substituents include a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, an amino group, —NHCOR ¹ , —COR ¹ and -COOR ¹ (wherein R ¹ is an alkyl group having 1 to 12 carbon atoms or a (hetero) aryl group having 12 or less carbon atoms), among which a halogen atom, particularly a chlorine atom is preferable.

1-3. Chromatic colorant having a dioxazine skeleton:
Examples of the chromatic colorant having a dioxazine skeleton include compounds containing a skeleton represented by the following general formula (7), and the colorant is usually a pigment.

  The colorant containing this skeleton may be a compound having a substituent or a compound having no substituent, but is preferably a compound having a substituent. The structure of the compound having a substituent is represented, for example, by the following general formula (8).

[Wherein, R ^{17 to} R ²² are each independently a halogen atom, —NHCOR ¹ (wherein R ¹ is an alkyl group having 1 to 12 carbon atoms or a (hetero) aryl group having 12 or less carbon atoms) And an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms. ]

The chromatic colorant having the dioxazine skeleton described above preferably has substituents R ¹⁷ and R ¹⁸ in the general formula (8). R ¹⁷ and R ¹⁸ are preferably a halogen atom or —NHCOR ^{1, and} more preferably —NHCOR ¹ . R ^{19 to} R ²² are preferably a halogen atom, —NHCOR ¹ , an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, or the like, and an alkoxyl group having 1 to 12 carbon atoms or —NHCOR ¹ is Further preferred.

1-4. Chromatic colorant having a quinacridone skeleton:
Examples of the chromatic colorant having a quinacridone skeleton include compounds containing a skeleton represented by the following general formula (9), and the colorant is usually a pigment.

  The colorant containing this skeleton may be a compound having a substituent or a compound having no substituent, but the structure of the compound having a substituent is represented by, for example, the following general formula (10).

In the above general formula (10), substituent ^is preferably linked to position of R 23 ^{to R 26.} Preferable substituents include halogen atoms or alkyl groups having 1 to 12 carbon atoms.

1-5. Chromatic colorant having a quinophthalone skeleton:
Examples of the chromatic colorant having a quinophthalone skeleton include compounds containing a skeleton represented by the following general formula (11), and the colorant is a pigment or a dye.

  The colorant containing this skeleton may be a compound having a substituent or a compound having no substituent, but the structure of the compound having a substituent is represented by, for example, the following general formula (12).

[Wherein R ^{27 to} R ³⁰ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms or a group containing a ring structure, and R ³¹ Is a hydrogen atom, a halogen atom, an alkoxyl group having 1 to 12 carbon atoms, an aryloxy group having 5 to 12 carbon atoms, a heteroaryloxy group having 1 to 12 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, or 5 carbon atoms. a 12 arylthio group or a heteroarylthio group having 1 to 12 carbon ^{atoms, R 32} is a hydrogen atom or a hydroxyl ^group, R 33 ^{to R 36} are each independently a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, -COOR ¹ or -CONR ¹² (where, ^{R 1} is 1 alkyl group carbon atoms or from 1 to 12 carbon atoms It is the following (hetero) aryl group.) Is. R ²⁸ and R ²⁹ , R ³¹ and R ³² , R ³³ and R ³⁴ , R ³⁴ and R ³⁵ , and R ³⁵ and R ³⁶ may be connected to each other to form a ring. ]

In said general formula (12), when R < ²⁷ > -R < ³⁰ > is group containing a ring structure, as this group, the substituent represented by the following general formula (13) is mentioned.

The structure of the colorant when R ²⁷ in the general formula (12) is a substituent represented by the general formula (13) is shown below as a general formula (14).

As a chromatic colorant having a quinophthalone skeleton represented by the general formula (14), R ^{28 to} R ³⁰ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms. A compound that is an alkoxyl group, R ³¹ and R ³² are hydrogen atoms, and R ^{33 to} R ³⁶ are halogen atoms is preferable. More preferred colorants are R ²⁸ and R ²⁹ are hydrogen atoms or halogen atoms, R ^{30 to} R ³² are hydrogen atoms, R ^{33 to} R ³⁶ are halogen atoms, and X ^{5 to} X ⁸ are It is a compound that is a halogen atom. This colorant is usually a pigment. Particularly preferred colorants are R ²⁸ and R ²⁹ are hydrogen atoms, R ^{30 to} R ³² are hydrogen atoms, R ^{33 to} R ³⁶ are halogen atoms (X ^{9 to} X ¹² ), and X ⁵ to X ⁸ is a compound which is a halogen atom (see the following general formula (15)).

In the above general formula ^{(12), R 27} and ^{R 30} is a hydrogen atom ^{and R28} and ^{R 29} is a halogen atom, an alkyl group or alkoxyl group having 1 to 12 carbon atoms having 1 to 12 carbon atoms ( The following general formula (16)) is usually a dye.

[Wherein, R ²⁸ and R ²⁹ are each independently a halogen atom, an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms, and R ³¹ is a hydrogen atom, a halogen atom, or a carbon atom. C1-C12 alkoxyl group, C5-C12 aryloxy group, C1-C12 heteroaryloxy group, C1-C12 alkylthio group, C5-C12 arylthio group, or C1-C1 a 12 a heteroarylthio ^{group, R 32} is a hydrogen atom or a hydroxyl ^group, R 33 ^{to R 36} are each independently a hydrogen atom, a halogen atom, a carboxyl group, an alkyl having 1 to 12 carbon atoms group, an alkoxyl group having 1 to 12 carbon ^atoms, -COOR 1, -CONR ¹² (where, ^{R 1} is from 1 to 12 carbon atoms alkyl group or having 12 or less carbon (hetero) aryl It is the is.). R ²⁸ and R ²⁹ , R ³¹ and R ³² , R ³³ and R ³⁴ , R ³⁴ and R ³⁵ , and R ³⁵ and R ₃₆ may be connected to each other to form a ring. ]

1-6. Chromatic colorant having anthraquinone skeleton:
Examples of the chromatic colorant having an anthraquinone skeleton include compounds containing a skeleton represented by the following general formula (17). The colorant may be a compound containing only one of the following skeletons or a compound containing two or more.

  As the colorant, a compound represented by the following general formula (18), a compound containing a plurality of the skeletons, and a compound having an amino group are preferable, and a compound having two anthraquinone skeletons and two amino groups is preferable. Particularly preferred. The compound represented by the following general formula (18) is usually a yellow to blue dye.

[Wherein, R ^{37 to} R ⁴⁴ are each independently a hydrogen atom, a halogen atom, an amino group, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, or an aryl group having 5 to 5 carbon atoms. 12 aryl group, heteroaryl group having 1-12 carbon ^{atoms, -NHR 1, -NR 12, -OR} 1, -SR 1, -COOR 1 or -NHCOR ¹ (where, ^{R 1} is 1 to 12 carbon atoms Or a (hetero) aryl group having 12 or less carbon atoms. ]

  Examples of the compound having two anthraquinone skeletons and two amino groups include compounds represented by the following general formula (19) and structural formula (20). These compounds are usually blue pigments.

[Wherein, R ⁴⁵ and R ⁴⁶ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 5 to 12 carbon atoms, a heteroaryl group having 1 to 12 carbon atoms, or 2 carbon atoms. An alkylcarbonyl group having 13 carbon atoms, an arylcarbonyl group having 6-13 carbon atoms, or a heteroarylcarbonyl group having 2-13 carbon atoms. ]

  In the compound represented by the structural formula (20), the hydrogen atom bonded to the aromatic ring may be substituted with a halogen atom or the like.

1-7. Chromatic colorant having a perylene skeleton:
Examples of the chromatic colorant having the above-described perylene skeleton include compounds represented by the following general formula (21), and the colorant is usually a pigment.

[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 5 to 12 carbon atoms, a heteroaryl group having 1 to 12 carbon atoms, or —COR ^1. Or —COOR ¹ (wherein R ¹ is an alkyl group having 1 to 12 carbon atoms and a (hetero) aryl group having 12 or less carbon atoms). ]

Represented by the aforementioned general formula (21), the chromatic coloring agent having a perylene ^skeleton, colorants ^{R 47} and ^{R 48} is an alkyl group having 1 to 12 carbon atoms are preferred, 1 to 3 carbon atoms More preferred are colorants that are alkyl groups.

1-8. Chromatic colorant having a metal complex skeleton:
Examples of the chromatic colorant having a metal complex skeleton include compounds in which metal ions are coordinated to an organic dye skeleton. Examples of the organic dye skeleton include those having an azo group, those having an azomethine group, and the like, and may have a hydroxyl group, an amino group, an imino group, or the like at the ortho or peri position of the azo group or azomethine group. Examples of metal ions include copper, nickel, cobalt, and zinc ions.

2. Black material for multicolor laser marking:
The black substance is not particularly limited as long as it is extinguished or discolored by receiving laser light. That is, the color of the irradiated portion of the laser beam in the laminate of the present invention is such that the influence of the color of the substance other than the black substance appears strongly, for example, by itself disappearing or changing color due to the energy of the laser beam. Any black material can be used. Note that “disappearance” of the black substance described above means that the black substance does not exist due to vaporization, volatilization or decomposition, and “discoloration” means that at least a part or all of the substance is a color different from that before light reception due to decomposition or the like. (Preferably white) (for example, black → light blue or white). Further, “black” of the black substance is a dark color including black, for example, red-black (brown-black), green-black, blue-black, purple-black, gray- Includes black colors such as black.

  As the black material described above, for example, an RSM30D type “RSM30D type” manufactured by Roffin Basel is used for a black test piece consisting of only 100 parts by weight of polymethyl methacrylate and 0.1 part by weight of a black material, and an output of 31 A, frequency When the laser beam with a wavelength of 5.5 kHz and a wavelength of 1,064 nm is irradiated, it is preferable that the irradiated portion changes color to a color other than white or black.

  The above-mentioned black substance may be an inorganic substance or an organic substance, and may be a pigment or a dye, and may further contain a compound or a mineral that is not included in these, as long as the excellent effects of the present invention are not impaired. The above black materials may be used alone or in combination of two or more. Examples of the black material include inorganic pigments such as carbon black, titanium black, and black iron oxide, graphite, activated carbon, and the like. Of these, a material that is easily foamed by laser light irradiation, which will be described later, such as carbon black, titanium black, and black iron oxide is preferably the main component, and in particular, a material that has carbon black as the main component is preferable.

Examples of carbon black include acetylene black, channel black, and furnace black. The lower limit of the average particle size of the carbon black is preferably 0.1 nm, more preferably 1 nm, particularly preferably 5 nm, most preferably 10 nm, and the upper limit is preferably 1,000 nm, more preferably 500 nm, especially Preferably it is 100 nm, most preferably 80 nm. The lower limit of the nitrogen adsorption specific surface area of the above carbon black is preferably from ^{1 m} 2 / g, more preferably ^{5 m} 2 / g, particularly preferably ^{10 m} 2 / g, and most preferably ^{20 m} 2 / g, the upper limit , preferably 1,0000m ² / g, more preferably 5,000 m ² / g, particularly preferably 2,000 m ² / g, and most preferably 1,500 m ² / g.

  When the thermoplastic polymer composition for multicolor laser marking used in the present invention (a) contains carbon black, it is known that when irradiated with laser light, the laser light is absorbed and vaporized. . When carbon black is vaporized and disappears, the color of the laser light irradiation part is less or no affected by the color derived from carbon black (black or dark color), and the thermoplastic polymer composition for multicolor laser marking (a) The influence of the color derived from components other than carbon black contained becomes strong, that is, the color is derived from a chromatic colorant.

  Titanium black is generally obtained by reducing titanium dioxide. The lower limit of the average particle diameter of the titanium black is preferably 0.01 μm, more preferably 0.05 μm, particularly preferably 0.1 μm, and the upper limit is preferably 2 μm, more preferably 1.5 μm, particularly preferably. Is 1.0 μm, most preferably 0.8 μm.

  It is known that the above-described titanium black changes to white titanium dioxide when irradiated with laser light. Therefore, as in the case of irradiating a composition containing carbon black with laser light, the color of the irradiated portion is reduced or eliminated, and the color is derived from a chromatic colorant.

Black iron oxide is generally an oxide of iron represented by Fe ₃ O ₄ or FeO · Fe ₂ O ₃ . The lower limit of the average particle diameter of the black iron oxide is preferably 0.01 μm, more preferably 0.05 μm, particularly preferably 0.1 μm, most preferably 0.3 μm, and the upper limit is preferably 2 μm, It is preferably 1.5 μm, particularly preferably 1.0 μm, and most preferably 0.8 μm.

  It is known that the above-described black iron oxide changes to reddish white when irradiated with laser light. Therefore, as in the case of irradiating the composition containing carbon black or titanium black with laser light, the color of the irradiated part is reduced or eliminated, and the color is derived from the chromatic colorant.

3. Multicolor laser marking polymer:
This polymer may be any polymer as long as it does not hinder multicolored color development by laser light irradiation. Accordingly, it is preferable to include a polymer such as thermoplasticity, thermosetting property, light (including electron beam in addition to visible light to ultraviolet light) curing property, and room temperature curing property. These may be any of resin, elastomer, polymer alloy, rubber and the like. Moreover, even if it uses by 1 type in the above-mentioned, you may use in combination of 2 or more types including the combined use of the other polymer which does not belong to these. The above-mentioned “curing” polymer includes an oligomer that becomes a polymer after curing.

  In addition, the timing of curing of the above-described curable polymer or the like is not particularly limited, and a film or sheet (hereinafter, referred to as “polyethylene”) using the thermoplastic polymer composition for multicolor laser marking used in the present invention (a). When both are collectively referred to as a molded product), the molded product may be irradiated with a laser beam or the like. Incidentally, the above-mentioned curable polymer and the like are the time of kneading with the chromatic colorant, the black substance, etc. in the present invention, the time when the thermoplastic polymer composition for multicolored laser marking (a) is used, and the molding It may not be hardened at the time of manufacture. In this case, an uncured polymer, oligomer, etc. will be indicated.

  Examples of the thermoplastic resin include polystyrene, styrene / acrylonitrile copolymer, styrene / maleic anhydride copolymer, (meth) acrylic acid ester / styrene copolymer, ABS resin and other styrene resins; rubber reinforced thermoplastic resin; Olefin resins such as polyethylene, polypropylene, ionomer, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, cyclic olefin copolymer, chlorinated polyethylene, etc .; polyvinyl chloride, ethylene / vinyl chloride polymer, polychlorinated Vinyl chloride resins such as vinylidene; acrylic resins such as (co) polymers using one or more (meth) acrylic esters such as polymethyl methacrylate (PMMA); polyamide 6, polyamide 6,6, polyamide Polyamide-based resin (PA) such as 6, 12; Polyester resins such as terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate; polyacetal resin (POM); polycarbonate resin (PC); polyarylate resin; polyphenylene ether; polyphenylene sulfide; polytetrafluoroethylene, polyfluoride Fluorine resins such as vinylidene; liquid crystal polymers; imide resins such as polyimide, polyamideimide, and polyetherimide; ketone resins such as polyetherketone and polyetheretherketone; sulfone resins such as polysulfone and polyethersulfone; urethane Resin; Polyvinyl acetate; Polyethylene oxide; Polyvinyl alcohol; Polyvinyl ether; Polyvinyl butyral; Phenoxy resin; Photosensitive resin; Chick, and the like. These may be used alone or in combination of two or more. Of these, rubber-reinforced thermoplastic resins, acrylic resins, polyamide resins (PA), polyacetal resins (POM), and urethane resins are preferable. The above-mentioned “rubber reinforced thermoplastic resin” is a rubber reinforced copolymer resin obtained by polymerizing a vinyl monomer in the presence of a rubbery polymer, or the rubber reinforced copolymer resin and a vinyl resin. It consists of a mixture with a monomeric (co) polymer.

Thermoplastic elastomers include olefin elastomers; diene elastomers; styrene elastomers such as styrene / butadiene / styrene block copolymers; polyester elastomers; urethane elastomers; vinyl chloride elastomers; polyamide elastomers; Is mentioned. These may be used alone or in combination of two or more.
Examples of the polymer alloy include PA / rubber reinforced thermoplastic resin, PC / rubber reinforced thermoplastic resin, PBT / rubber reinforced thermoplastic resin, PC / PMMA, and the like. These may be used alone or in combination of two or more.

  Rubbers include natural rubber, isoprene rubber, butadiene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, chloroprene rubber, butyl rubber, ethylene / propylene rubber, acrylic rubber, urethane rubber, chlorinated polyethylene, silicone rubber, epichlorohydrin rubber, fluorine Examples thereof include rubber and polysulfide rubber. These may be used alone or in combination of two or more.

  Examples of curable polymers such as thermosetting, photocurable, and room temperature curable polymers include acrylic resins (including acrylic polymers having an epoxy group), epoxy resins, phenolic resins, unsaturated polyester resins, and alkyds. Resins, melamine resins, urethane resins, urea resins, silicone resins, polyimide resins, bismaleimide / triazine resins, furan resins, xylene resins, guanamine resins, dicyclopentadiene resins, and the like. These may be used alone or in combination of two or more. These resins may contain a curing agent or the like, or may be composed only of a self-crosslinking polymer. Of these, an acrylic polymer having an epoxy group is preferred.

  In addition, when the above-described polymer includes a polymer that is easily foamed by receiving laser light, multicolor coloring by laser light irradiation becomes clearer. Therefore, when the above-mentioned polymer is irradiated with laser light having an output of 31 A, a frequency of 5.5 kHz, and a wavelength of 1,064 nm, using the above-mentioned “RSM30D type” on a test piece made of only the polymer, A polymer in which the foamed state is observed with an electron microscope in the cross section of the irradiated part is preferable.

  When the laminate of the present invention is irradiated with laser light and the irradiated part becomes a foamed part, depending on the behavior of the chromatic colorant during laser light irradiation, the laser light irradiated part (foamed part) and its surroundings are not irradiated. The difference in refractive index from the portion increases, and the marking becomes clearer. For example, when the chromatic colorant is decomposed or scattered by a high-energy laser beam, the color of the white color or the color derived from the colorant is reduced. ) And the surrounding non-irradiated part is large, so that a clearer marking is formed.

  Among the above-mentioned polymers, (1) rubber reinforced thermoplastic resin using methyl methacrylate as a monomer component, (2) polymethyl methacrylate (PMMA), 30% by weight or more of methyl methacrylate monomer unit An acrylic resin such as a copolymer, (3) a polyacetal resin, and (4) a polyamide resin such as a polyamide resin are easy to foam and are preferable.

  The rubber-reinforced thermoplastic resin preferred in the present invention is a rubber-reinforced copolymer resin (A1) obtained by polymerizing the vinyl monomer (b1) in the presence of the rubbery polymer (a), or the rubber In a mixture of the reinforced copolymer resin (A1) and the (co) polymer (A2) of the vinyl monomer (b2), the rubber reinforced copolymer resin (A1) or the (meth) acrylic acid ester alone in the mixture Among the components other than the rubbery polymer (a), the monomer unit amount is preferably 30% by weight or more, more preferably 40% by weight or more, and further preferably 50% by weight or more. If it is out of this range, a clear marking may not be easily obtained.

As described above, it is preferable to use a (meth) acrylic acid ester for the formation of the rubber-reinforced copolymer resin (A1) and the (co) polymer (A2) of the vinyl monomer (b2). In the presence of the rubbery polymer (a), a vinyl monomer containing a (meth) acrylic acid ester (
From the rubber-reinforced copolymer resin (A1) obtained by polymerizing b1) or a mixture of the rubber-reinforced copolymer resin (A1) and the (co) polymer (A2) of the vinyl monomer (b2) The rubber-reinforced copolymer resin is particularly preferable. When the vinyl monomer (b1) is polymerized in the presence of the rubber polymer (a), the vinyl polymer (b1) is usually graft-polymerized to the rubber polymer. A mixture of the component and the (co) polymer component of the vinyl monomer (b1) which is not grafted is obtained.

  Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, and isobutyl acrylate. Acrylates such as amyl acrylate, hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, benzyl acrylate; methyl methacrylate, Ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, amyl methacrylate, methacrylic acid Hexyl methacrylate n- octyl, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate, and methacrylic acid esters of benzyl methacrylate. These compounds may be used alone or in combination of two or more. Of these compounds, methyl methacrylate is particularly preferred.

  Examples of the rubber polymer (a) include polybutadiene, butadiene / styrene copolymer, butadiene / acrylonitrile copolymer, styrene / butadiene / styrene block copolymer, styrene / isoprene / styrene block copolymer, isobutylene / Polymers such as isoprene copolymers; Hydrogenated products of these polymers; Butyl rubbers; Ethylene / α-olefin copolymers; Ethylene / α-olefin / non-conjugated diene copolymers; Silicone rubbers; Acrylic rubbers It is done. These polymers may be used alone or in combination of two or more.

  The vinyl monomer (b1) used for forming the rubber-reinforced copolymer resin (A1) includes an aromatic vinyl compound, a vinyl cyanide compound, a maleimide compound, etc. in addition to the (meth) acrylic acid ester. But you can. Moreover, you may use the vinyl type compound which has functional groups, such as an epoxy group, a hydroxyl group, a carboxyl group, an amino group, and an oxazoline group, as needed. These compounds may be used alone or in combination of two or more.

  The vinyl monomer (b2) used for the formation of the above (co) polymer (A2) includes the above (meth) acrylic acid ester; aromatic vinyl compound; vinyl cyanide compound; maleimide compound. A vinyl compound having a functional group such as an epoxy group, a hydroxyl group, a carboxyl group, an amino group, or an oxazoline group; These compounds may be used alone or in combination of two or more. In addition, as for the above-mentioned vinyl monomer (b1) and vinyl monomer (b2), the same monomer may be used in the same amount or in different amounts, and different types of monomers are used. May be.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, ethylstyrene, vinyltoluene, vinylxylene, methyl-α-methylstyrene, t-butylstyrene, divinylbenzene, 1, Chlorinated styrene such as 1-diphenylstyrene, N, N-diethyl-p-aminomethylstyrene, N, N-diethyl-p-aminoethylstyrene, vinylnaphthalene, vinylpyridine, monochlorostyrene, dichlorostyrene; monobromostyrene, Brominated styrene such as dibromostyrene; monofluorostyrene and the like. These compounds may be used alone or in combination of two or more. Of these, styrene, α-methylstyrene, and p-methylstyrene are preferable.

  Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like. These compounds may be used alone or in combination of two or more. Of these, acrylonitrile and methacrylonitrile are preferred.

  As maleimide compounds, maleimide, N-methylmaleimide, N-butylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-hydroxyphenyl) maleimide, N-cyclohexylmaleimide, α, Examples include β-unsaturated dicarboxylic acid imide compounds. These compounds may be used alone or in combination of two or more. The maleimide compound unit may be introduced into the above-described polymer by copolymerization of maleic anhydride and then imidization.

  Examples of the vinyl compound having the above functional group include glycidyl methacrylate, glycidyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, N, N-dimethylaminomethyl acrylate, N , N-dimethylaminomethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, acrylamide, vinyl oxazoline and the like. These compounds may be used alone or in combination of two or more.

Of the vinyl monomer (b1) used for the formation of the rubber-reinforced copolymer resin (A1) or the vinyl monomer (b2) used for the formation of the (co) polymer (A2). The amounts used (all in weight units) are as follows.
(1) When an aromatic vinyl compound is used, the lower limit of the amount used with respect to the total amount of the vinyl monomer is preferably 5, more preferably 10, particularly preferably 20, and the upper limit is preferably 100, 80 is preferable.

(2) When a vinyl cyanide compound is used, the lower limit of the amount used with respect to the total amount of the vinyl monomer is preferably 1, more preferably 3, particularly preferably 5, and the upper limit is preferably 50, Preferably 40, particularly preferably 35.

(3) When (meth) acrylic acid ester is used, the lower limit of the amount used relative to the total amount of vinyl monomer is preferably 1, more preferably 5, and the upper limit is preferably 100, more preferably 95. And particularly preferably 90.

(4) When using a maleimide compound, the lower limit of the amount used with respect to the total amount of the vinyl monomer is preferably 1, more preferably 5, the upper limit is preferably 70, more preferably 60, Particularly preferred is 55.

(5) When using a vinyl compound having a functional group, the lower limit of the amount used with respect to the total amount of the vinyl monomer is preferably 0.1, more preferably 0.5, and particularly preferably 1, the same upper limit. Is preferably 30, more preferably 25. It is preferable that the amount of the vinyl monomer used is in the above-mentioned range since the effect of the monomer used is sufficiently exhibited.

  The rubber-reinforced copolymer resin (A1) can be produced by a method using emulsion polymerization, solution polymerization, bulk polymerization, or the like, in the presence of the rubbery polymer (a). it can. Of these, emulsion polymerization is preferred. In the case of producing by emulsion polymerization, a polymerization initiator, a chain transfer agent (molecular weight regulator), an emulsifier, water and the like are used.

  The method for using the vinyl monomer (b1) in emulsion polymerization of the vinyl monomer (b1) in the presence of the rubber polymer (a) is usually as follows. In the present invention, the method of using the vinyl monomer (b1) when polymerizing the vinyl monomer (b1) in the presence of the rubbery polymer (a) is not limited to this method of use. In the reaction system, the vinyl monomer (b1) may be added all at once in the presence of the total amount of the rubbery polymer (a), or may be added in portions or continuously. Moreover, you may add the whole quantity or one part of rubber-like polymer (a) in the middle of superposition | polymerization.

  As the above-mentioned polymerization initiator, organic hydroperoxides represented by cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide and the like, sugar-containing pyrophosphate prescription, sulfoxylate prescription and the like are representative. Redox compounds in combination with reducing agents, or persulfates such as potassium persulfate, peroxides such as benzoyl peroxide (BPO), lauroyl peroxide, t-butyl peroxylaurate, t-butyl peroxymonocarbonate These may be used alone or in combination of two or more. The addition to the reaction system may be performed all at once or continuously. In addition, the usage-amount of this polymerization initiator is 0.1-1.5 weight% normally with respect to the whole quantity of the above-mentioned vinylic monomer (b1), Preferably it is 0.2-0.7 weight%. is there.

  Examples of the chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan; Examples include α-methylstyrene dimers, which may be used alone or in combination of two or more. The amount of the chain transfer agent used is usually 0.05 to 2.0% by weight with respect to the total amount of the vinyl monomer (b1).

  Examples of the above-mentioned emulsifiers include higher alcohol sulfates, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; aliphatic sulfonates such as sodium lauryl sulfate; higher aliphatic carboxylates; anionic interfaces such as rosinate Nonionic surfactants such as activator; polyethylene glycol alkyl ester type; alkyl ether type and the like. These may be used alone or in combination of two or more. The usage-amount of this emulsifier is 0.3 to 5.0 weight% normally with respect to the whole quantity of the above-mentioned vinylic monomer (b1).

  The latex obtained by emulsion polymerization is usually purified by coagulation with a coagulant to make the polymer component into powder, and then washing and drying. Examples of the coagulant include inorganic salts such as calcium chloride, magnesium sulfate, magnesium chloride, and sodium chloride; inorganic acids such as sulfuric acid and hydrochloric acid; organic acids such as acetic acid and lactic acid. A known method can be applied to the production method by solution polymerization or bulk polymerization.

  The graft ratio of the graft polymer contained in the rubber-reinforced copolymer resin (A1) described above (weight ratio of the vinyl monomer (b1) grafted to the rubbery polymer (a)) is preferably 10 to 200%. More preferably, it is 15 to 150%, particularly preferably 20 to 100%. If the graft ratio of the graft polymer is too low, the impact strength may be reduced. Moreover, when too high, workability will be inferior.

  Here, the graft ratio is xg of rubber component in 1 g of rubber-reinforced copolymer resin (A1), 1 g of rubber-reinforced copolymer resin (A1) is acetone (however, acrylic rubber as rubbery polymer (a)) Is used, it is a value calculated | required by following Formula, when insoluble content at the time of making it melt | dissolve in acetonitrile is used as yg.

  The graft ratio (%) is determined by the kind and amount of a polymerization initiator, a chain transfer agent, an emulsifier, a solvent, etc., and also a polymerization time, a polymerization temperature, etc. By changing, it can be easily controlled.

  The above (co) polymer (A2) can be obtained, for example, by bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization or the like.

  The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the acetone-soluble component of the (co) polymer (A2) is preferably from the viewpoint of a balance between physical properties of molding processability and impact resistance. 1 to 1.0 dl / g, more preferably 0.15 to 0.7 dl / g. The intrinsic viscosity [η] can be controlled by adjusting the production method, like the rubber-reinforced copolymer resin (A1). Further, the intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the acetone-soluble component of the rubber-reinforced thermoplastic resin is preferably 0.1 from the viewpoint of the balance between physical properties of molding processability and impact resistance. It is -0.8 dl / g, More preferably, it is 0.15-0.7 dl / g.

  The above rubber-reinforced thermoplastic resins may be used alone or in combination of two or more. Examples of preferred embodiments of the rubber-reinforced thermoplastic resin described above are shown in (1) to (4) below.

(1) A rubber-reinforced copolymer resin obtained by polymerizing a monomer containing methyl methacrylate in the presence of a rubbery polymer.

(2) A rubber-reinforced thermoplastic resin obtained by combining the above (1) and a (co) polymer obtained by polymerizing a monomer containing methyl methacrylate.

(3) A rubber-reinforced thermoplastic resin obtained by combining the above (1) and a (co) polymer obtained by polymerizing a monomer containing an aromatic vinyl compound and a vinyl cyanide compound.

(4) A rubber-reinforced copolymer resin obtained by polymerizing a monomer containing an aromatic vinyl compound and a vinyl cyanide compound without using methyl methacrylate in the presence of a rubbery polymer, and methacrylic acid A rubber-reinforced thermoplastic resin combined with a (co) polymer obtained by polymerizing a monomer containing methyl.

  When the polymer in the present invention mainly contains the above-described rubber-reinforced thermoplastic resin, a composition giving a molded article having excellent impact resistance can be obtained. When the polymer in the present invention contains the above-mentioned rubber-reinforced thermoplastic resin, the lower limit of the content of rubbery polymer (a) in the polymer (all units are% by weight) is preferably 0.5. More preferably 1, particularly preferably 3, most preferably 5, and the upper limit is preferably 60, more preferably 40, and particularly preferably 35. If the content of the rubbery polymer (a) is too small, the impact resistance of the molded product tends to be inferior, and if it is too much, the hardness and rigidity tend to be inferior.

As the polymer in the present invention, the above rubber-reinforced thermoplastic resin may be used alone or in combination with other polymers. Other polymers include polycarbonate resins, polyester resins, polyamide resins and other thermoplastic resins; acrylic resins (including acrylic polymers having an epoxy group), epoxy resins, phenolic resins, unsaturated polyester resins Examples thereof include thermosetting resins such as resins, alkyd resins, melamine resins, urethane resins, and urea resins. These other polymers may be used alone or in combination of two or more.

  In addition, a preferable acrylic resin in the present invention is a (co) polymer formed from a monomer containing a (meth) acrylic acid ester. As the (meth) acrylic acid ester, the rubber reinforcement described above is used. It is preferable to contain the (meth) acrylic acid ester used for forming the thermoplastic resin. Examples of other monomers include aromatic vinyl compounds; vinyl cyanide compounds; maleimide compounds; vinyl compounds having functional groups such as epoxy groups, hydroxyl groups, carboxyl groups, amino groups, and oxazoline groups. Therefore, as the above-mentioned acrylic resin, a resin obtained using a monomer containing methyl methacrylate is particularly preferable, and a (co) polymer containing 30% by weight or more of a methyl methacrylate monomer unit, polymethacrylic acid, Methyl acid (PMMA) and the like are preferable.

  A copolymer comprising 30 to 80% by weight of methyl methacrylate, 20 to 50% by weight of (meth) acrylic acid ester other than methyl methacrylate, and 0 to 50% by weight of other vinyl monomers is also preferable. As a commercial product of a methyl methacrylate / butyl acrylate / styrene soft copolymer, there is “Parapellet SA-N” (trade name) manufactured by Kuraray Co., Ltd.

  The weight average molecular weight in terms of polystyrene by gel permeation chromatography (GPC) of the above acrylic resin is not particularly limited, but is preferably 50,000 to 500,000, more preferably 70,000 to 400,000, particularly preferably. Is 80,000-300,000.

  In addition, the polyacetal resin preferable in the present invention is not particularly limited as long as it is a polymer compound having an oxymethylene group (—CH 2 O—) as a main structural unit. The polyacetal resin may be any of a polyoxymethylene homopolymer, a copolymer (including a block copolymer) containing other structural units in addition to an oxymethylene group, and a terpolymer. It may have a branched or crosslinked structure. Moreover, this polyacetal resin may have functional groups, such as a carboxyl group and a hydroxyl group. Furthermore, the polyacetal resin may be used alone or in combination of two or more.

  In addition, the polyamide resin preferable in the present invention is not particularly limited as long as it is a polymer compound having an acid amide bond (—CO—NH—) in the main chain.

  As the above-mentioned polyamide resin, nylon 4, 6, 7, 8, 11, 12, 6.6, 6.9, 6.10, 6.11, 6.12, 6T, 6 / 6.6, 6 / 12, 6 / 6T, 6T / 6I and the like. The terminal of the polyamide resin may be sealed with carboxylic acid, amine or the like. The above polyamide resins may be used alone or in combination of two or more.

  Further, the polyurethane resin preferable in the present invention is not particularly limited as long as it is a polymer compound having a urethane bond (—NH—COO—) in the main chain. The polyurethane resin is usually obtained by reacting diol and diisocyanate.

  As described above, as the laser marking polymer in the present invention, a thermoplastic polymer and a thermosetting polymer can be used in combination. In this case, the heat for the thermoplastic polymer content of 100 parts by weight is used. The lower limit of the content of the curable polymer is preferably 0.01 parts by weight, more preferably 0.05 parts by weight, particularly preferably 0.1 parts by weight, and the upper limit is preferably 20 parts by weight, The amount is preferably 10 parts by weight, particularly preferably 5 parts by weight. By setting the content of the thermosetting polymer to the above, the marking portion is not discolored (including fading), and a clear color development is maintained for a long period of time, so that the shape of the marking portion tends to be more stable. In the case where the thermoplastic polymer and the thermosetting polymer are used in combination, in the thermoplastic polymer composition (a) for multicolor laser marking used in the present invention, the thermosetting polymer is in a connected state. It may be included or may be contained in a dispersed state as small pieces such as particles.

4). Thermoplastic polymer composition for multicolor laser marking:
The resin composition (a) for multicolor laser marking used in the present invention contains the above-mentioned chromatic colorant, black material and polymer in predetermined amounts, and has different energy for the composition. By irradiating two or more laser beams, two or more different color tones are marked.

  In order to obtain a clear marking, the thermoplastic polymer composition (a) for multicolor laser marking used in the present invention has the composition of the above-described components in the following ranges. That is, when it is 100 parts by weight of the polymer, the content of the chromatic colorant is 0.001 to 3 parts by weight, and the content of the black substance is 0.01 to 2 parts by weight. The lower limit of the content of the chromatic colorant is preferably 0.002 parts by weight, particularly preferably 0.005 parts by weight, and the upper limit is preferably 1 part by weight, particularly preferably 0.8 parts by weight. . If there is too much content of the above-mentioned chromatic colorant, it will be difficult to obtain white marking, etc., and it will be difficult to distinguish between high-energy laser light irradiation parts and low-energy laser light irradiation parts due to high-energy laser light irradiation. Prone. On the other hand, when the amount is too small, it becomes difficult to distinguish between the low-energy laser light irradiation and the unirradiated portion, such as difficult to obtain a color marking derived from the chromatic colorant.

  The lower limit of the black substance content is preferably 0.03 parts by weight, particularly preferably 0.05 parts by weight, and the upper limit is preferably 1 part by weight, particularly preferably 0.8 parts by weight. . When there is too much content of the above-mentioned black substance, a laser beam irradiation part will be too black and it will become difficult to identify the marking by laser beam irradiation. In addition, when using a curable polymer as the above-mentioned polymer, a raw material component shall be adjusted so that "the polymer after hardening is 100 weight part".

  The ground color of the thermoplastic polymer composition (a) for multicolor laser marking used in the present invention is black or dark because the chromatic colorant, black substance, etc. are dispersed in the above polymer. Presents a color. In the present invention, by further including a white material such as a white material, the brightness of the ground color can be adjusted and the whiteness of the color developed during laser marking can be improved. In the latter case, for example, it is possible to improve the whiteness of a white color developed by laser light irradiation or a color having a reduced color density derived from the colorant used in the present invention.

  As the above-mentioned white-based material, any white-based material may be used as long as it does not significantly hinder the excellent performance of the multicolor coloring marking according to the present invention, such as making it very difficult to identify the marking according to the present invention. For example, titanium dioxide, zinc oxide, zinc sulfide, barium sulfate and the like can be mentioned. These may be used alone or in combination of two or more.

  The average particle size of the white substance is not particularly limited, but is usually 0.1 to 3.0 μm, preferably 0.1 to 2.0 μm, and more preferably 0.1 to 1.0 μm. The content of the white substance is preferably 0.001 to 1 part by weight, more preferably 0.001 to 0.5 part by weight, and still more preferably 0.001 to 100 parts by weight of the polymer. -0.1 parts by weight. If the content is too large, markings with good contrast may not be obtained. On the other hand, if the content is too small, the degree of freedom of the ground color after molding may be limited.

  The thermoplastic polymer composition for multi-color laser marking used in the present invention (a) is an ultraviolet absorber, an antioxidant, an anti-aging agent, an antistatic agent, a flame retardant, depending on the purpose and application. You may contain additives, such as a weathering agent, a plasticizer, a filler, a lubricant, an antibacterial agent, a hydrophilicity imparting agent, a decorating agent, and a light-colored colorant. In particular, when each contains a predetermined amount of antistatic agent, flame retardant, filler, antibacterial agent, decorating agent, etc., not only a clear colored marking is obtained, but also the desired function is exhibited at a high level. A molded product to be maintained can be obtained.

  The thermoplastic polymer composition (a) for multicolor laser marking used in the present invention is prepared by, for example, charging the above-described components into various extruders, Banbury mixers, kneaders, rolls, and the like and kneading them. Obtainable. As a kneading method, each component may be added all at once or may be kneaded by a multistage addition method.

  By the way, in the above (rubber-reinforced) acrylic thermoplastic resin composition, when a polycarbonate resin is contained, a peculiar pearl luster is inevitably generated due to a difference in refractive index between the acrylic resin and the polycarbonate resin. Such pearly luster is not preferable when white is expressed in the black matrix color. Therefore, in the present invention, the phosphoric acid ester described in Japanese Patent Application No. 2004-267602 as a compatibilizing agent for the polycarbonate resin (A) and the acrylic resin (B) in order to prevent the above pearly luster. It is recommended to use the system compound (C).

  The “phosphate ester compound (C)” is the following (C-1) and / or the following (C-2).

<Transparent thermoplastic resin (b)>
The resin used for the transparent thermoplastic resin (b) is not particularly limited as long as it is a transparent thermoplastic resin having a light transmittance of 70% or more in a single layer having a thickness used as a laminate. Methyl) methacrylate resin, polycarbonate resin, polyolefin resin and the like. Of these, polyester resins are preferred.

  The light transmittance is measured using a spectrophotometer “V-570” manufactured by JASCO Corporation and using a light beam having a wavelength in the range of 200 to 1,100 nm. In the present invention, the light transmittance of 70% or more means that the light transmittance is 70% or more when measured with a light beam having at least one wavelength in the above range. The light transmittance is preferably 80% or more, more preferably 90% or more. When the light transmittance is less than 70%, the color developability by laser marking is poor.

  As the polyester resin, a polyester resin in which 50 mol% or more of all dicarboxylic acid components are composed of a terephthalic acid component and 50% or more of all diol components are composed of an ethylene glycol component is suitable.

Examples of dicarboxylic acid components other than terephthalic acid include phthalic acid, isophthalic acid, 4
, 4′-diphenyldicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and other aromatic dicarboxylic acids One or more of aliphatic dicarboxylic acids such as acids, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid and diglycolic acid Is mentioned.

  Examples of diol components other than ethylene glycol include propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol and other aliphatic diols, 1,2-cyclohexane. Alicyclic diols such as diol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, pyrocatechol, resorcinol, hydroquinone, 4,4′-dihydroxybiphenyl, 2,2 -Bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4 β- hydroxyethoxy phenyl) one or two or more aromatic diols of sulfone, and the like.

  Further, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid. Monofunctional components such as benzoylbenzoic acid, trifunctional or polyfunctional components such as trimellitic acid, trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, etc. May be used as a copolymerization component.

  Among them, isophthalic acid is used as the dicarboxylic acid component other than the terephthalic acid component, and 1,4-cyclohexanedimethanol (hereinafter abbreviated as 1,4-CHDM) is used as the diol component other than ethylene glycol. Further, terephthalic acid is the main component as the dicarboxylic acid component, ethylene glycol and 1,4-CHDM are the main components as the diol component, and the 1,4-CHDM ratio in the total diol component is the total diol component A polyester resin that is 15 to 50 mol% is particularly suitable, and examples of such a polyester resin include “EASTAR PETG Copolymerester 6663” (trade name) manufactured by Eastman Chemical Co., Ltd. In addition, the main component said here shows that it is 85 mol% or more in each component, Preferably it is 90 mol% or more.

  The transparent thermoplastic resin (b) is preferably subjected to an antiblocking treatment. The anti-blocking treatment is achieved by roughening using inert particles. And the roughening using an inert particle is dried after apply | coating an inert particle containing coating liquid to the method which mix | blends an inert particle with a transparent thermoplastic resin (b) in a manufacturing process of a laminated body, or a laminated body. Any of the methods may be used. However, in the case of the former method, the effect of improving the slipperiness in the production process of the laminate is remarkable.

  Examples of the inert particles include silicon oxide, titanium oxide, zeolite, silicon nitride, boron nitride, celite, alumina, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, calcium phosphate, lithium phosphate, phosphorus Examples thereof include magnesium oxide powder, lithium fluoride, kaolin, talc, and crosslinked polymer fine powder as described in JP-B-59-5216.

  The average particle diameter of the inert particles is usually 1.0 to 10 μm, preferably 2.0 to 6.0 μm. When the average particle size is less than 1.0 μm, the effect of improving slipperiness is not sufficient, and when it exceeds 10 μm, the transparency of the transparent thermoplastic resin layer is impaired. The content of inert particles is usually 0.05 to 2.0% by weight, preferably 0.1 to 1.5% by weight, and more preferably 0.2 to 1.0% by weight. When the content is less than 0.05% by weight, the effect of improving slipperiness is not sufficient, and when it exceeds 2.0% by weight, the transparency of the transparent thermoplastic resin layer is impaired.

  As a method of blending the inert particles into the transparent thermoplastic resin layer, any currently known method can be employed. For example, it can be added during polymerization, mixed with a transparent thermoplastic resin after polymerization using a blender, or a master batch with a high concentration of inert particles can be prepared, diluted and mixed into a transparent thermoplastic resin. Can be blended.

  In addition to the above-mentioned inert particles, an antistatic agent, a stabilizer, a lubricant, an ultraviolet absorber, and various additives can be added to the transparent thermoplastic resin layer as long as the slipperiness and transparency are not impaired. I can do it. Furthermore, a lubricant such as an antistatic agent, silicone, or wax can be applied to the surface of the transparent thermoplastic resin layer. By applying the lubricant, high blocking resistance is imparted in combination with the roughening using the inert particles. That is, the problem of blocking when stored as a single wafer is solved all at once.

A suitable example of the lubricant is dimethylsiloxane. Usually, dimethylsiloxane is used as an emulsion, and is used as an emulsion having a solid concentration of 1 to 5% by weight at a rate of 1 to 5 ml / m ² .

<Laminate>
The laminate of the present invention has a basic layer structure in which a B layer is laminated on at least one surface of an A layer, and the A layer / B layer is formed. Other layer configurations include B layer / A layer / B layer. In such a three-layer configuration, the two B layers may be formed of different types of transparent thermoplastic resins (b). Further, other layer configurations include B layer / A layer / C layer or B layer / A layer / C layer / B layer. The C layer can be formed of a resin excellent in light resistance such as polymethyl methacrylate (PMMA). The laminated body of the preferable other aspect of this invention has the layer structure which consists of B layer / A layer / C layer.

  Although the manufacturing method of the laminated body of this invention is not specifically limited, Usually, a coextrusion method is employ | adopted. For example, after each resin is dried by a conventional method, it is supplied to a separate extruder and extruded from a multi-manifold die or a feed block die at a predetermined temperature, and is usually adjusted to 0 to 80 ° C., preferably 10 to 50 ° C. A laminated sheet is formed by cooling and solidifying on a casting drum. At this time, it is preferable that one or more touch rolls are provided in the vicinity of the casting drum, and the touch rolls are used as pressing rolls when forming a sheet from the viewpoint of obtaining a laminate having a uniform thickness. By attaching a vent port to the extruder, the drying process can be omitted or the drying time can be shortened.

  The melting temperature of the thermoplastic polymer composition (a) for multicolor laser marking is usually 200 to 260 ° C. The melting temperature of the transparent thermoplastic resin (b) varies depending on the type of resin. In the case of a polyester resin, it is usually 240 to 310 ° C. In the case of polycarbonate resin, it is usually 280 to 320 ° C, in the case of polyethylene resin, it is usually 180 to 220 ° C, and in the case of PMMA, it is usually 260 to 320 ° C.

  The thickness of each layer is usually controlled by adjusting the amount of molten resin discharged from each extruder. The thickness of each layer in the above layer structure varies depending on the use mode of the laminate (film use or sheet use). The thickness of the A layer is usually 40 to 50 mm, and the thickness of the B and C layers is 5 to 5 mm. The ratio of the thickness of the A layer to the total thickness of the laminate is usually 90 to 95%.

  In the case of applying a lubricant such as an antistatic agent, silicone, wax or the like to the surface of the laminate obtained as described above, after treatment with an anti-blocking agent coating device provided in the downstream of the casting drum, for example, After being dried for 5 to 30 seconds in a dryer maintained at 20 to 70 ° C., it is supplied to a cutting device while being kept horizontal by a guide roll so as not to curl. Cut to size and stacked. The laminate of sheet products obtained in this way is shipped after being packaged.

  Moreover, the laminated body of this invention can be manufactured by the dry lamination method and the apply | coating method other than said coextrusion method. For example, in the case of the coating method, a film or sheet corresponding to the A layer is produced, and a coating layer is formed on the surface of the film or sheet so as to correspond to the B layer or the C layer. Moreover, in the dry laminating method or the coating method, the portion corresponding to the A layer can be a molded product other than a film or a sheet.

  That is, the thermoplastic polymer composition for multi-color laser marking used in the present invention (a) itself or further mixed with other polymers, and then injection molding, extrusion molding, hollow molding, compression molding Further, a molded product having a predetermined shape can be obtained by a molding method such as sheet extrusion, vacuum molding, foam molding, or blow molding. The shape of such a molded product can be selected from various shapes depending on the purpose, application, etc., and if the laser beam can be irradiated, the marked portion has a flat surface, a curved surface, and an uneven surface having a corner. Etc. The above-mentioned molded article contains at least a polymer, a chromatic colorant, and a black substance, and the background color is usually a black or dark color.

<Multicolor laser marking method>
By irradiating the laminate of the present invention with two or more laser beams having different energies, two or more different color tone markings can be formed. In general, the “energy” of a laser beam depends on the irradiation condition of the laser beam. Specifically, by changing the type, wavelength, pulse width, frequency, output, irradiation time, irradiation area, distance and angle from the light source to the laminate, irradiation method, etc. The laser light can be “having different energy” when irradiated with laser light. Specifically, not only when laser beams having different wavelengths are used, but also when other irradiation conditions such as irradiation time are different using laser beams having the same wavelength, different energies can be obtained. In addition, with the same irradiation conditions, the energy for the object to be irradiated is different in the case of one-time irradiation and in the case of two-time irradiation. In this case, the latter having a longer irradiation time is “higher energy”.

  In addition, “two or more laser beams having different energies” in the present invention refers to two or more laser beams having different degrees of damage to an irradiated object. When all of the above irradiation conditions are the same, the damage given to the irradiated object is different between the case where the irradiation is performed once and the case where the irradiation is performed in a plurality of times. 2 or more laser beams having “ In other words, even if the total energy to be applied is the same, if the irradiated object receives more damage than irradiated twice, the former is set to “high energy”.

  In the laser marking method according to the present invention, the laser beam irradiated on the laminate may be performed under any irradiation condition as long as the excellent performance of the multicolor laser marking according to the present invention is not significantly impaired. The irradiation method may be either a scanning method or a mask method, and two or more laser beams having different energies may be irradiated simultaneously or may be irradiated one by one. Moreover, as a laser beam irradiation device, a general laser marking device or the like can be used. The apparatus is usually equipped with a laser oscillator, a laser modulator, a handling unit, a controller, etc., and laser light oscillated from the laser oscillator is pulse-modulated by the laser modulator and irradiated on the surface of the laminate. Marking is formed. In laser marking, two or more laser beams having different energies may be irradiated with one device, or a plurality of devices may be used. As an apparatus capable of two-wavelength laser marking, for example, a laser marking system “RSM50D type”, “RSM30D type” manufactured by Roffin Basel, Inc. can be used.

The laser beam used in the present invention may be any of gas, solid, semiconductor, dye, excimer and free electron, but preferably has a wavelength in the range of 100 to 2,000 nm. In the present invention, for example, the numbers indicating the “wavelength” of laser light such as 1,064 nm and 532 nm all mean the center wavelength, and normally include an error of ± 3%.

  Examples of the gas laser include a helium / neon laser, a rare gas ion laser, a helium / cadmium laser, a metal vapor laser, and a carbon dioxide laser. Examples of the solid laser include a ruby laser, a neodymium laser, and a wavelength tunable solid laser. The semiconductor laser may be inorganic or organic, and examples of the inorganic semiconductor laser include GaAs / GaAlAs, InGaAs, and InP. A semiconductor laser-excited solid laser such as Nd: YAG, Nd: YVO4, or Nd: YLF can also be used. The laser beams exemplified above may be used alone or in combination of two or more.

  According to the multicolor laser marking according to the present invention, when the laminate of the present invention is irradiated with laser light, the color of the material other than the black material appears strongly in the portion where the black material has changed (disappeared, discolored, etc.). The portion where the change (decomposition, scattering, etc.) of the chromatic colorant occurs becomes a color with a reduced color density derived from the chromatic colorant or white. If the energy of the laser beam is low, the black material will disappear due to vaporization, volatilization, complete decomposition, etc .; or at least a part or all of the black material will remain there, and the discoloration will be different from the original black due to decomposition, etc. As a result, the laser beam irradiation section develops a color derived from the chromatic colorant. When the energy of the laser beam is further increased, the change of the chromatic colorant contained in the thermoplastic polymer composition (a) for multicolor laser marking used in the present invention is usually changed as described above. Therefore, the high-energy laser beam irradiation section develops a white color or a color with a reduced color density derived from a chromatic colorant.

An example of a coloring method by laser light irradiation will be briefly described with reference to the drawings. However, the multicolor coloring laser marking method according to the present invention is not limited thereto.
The laminated body (1) of the present invention is irradiated with laser beams having two different energies at different positions ([I] in FIG. 1). At this time, laser beam irradiation may be performed simultaneously or separately. The irradiated portion of the low energy laser light is marked with a color derived from the chromatic colorant ((3a) in FIG. 1), while the irradiated portion of the high energy laser light is white or chromatic colorant. Is marked ((3b) in FIG. 1) ([II] in FIG. 1). In the above manner, a laminate (1) (a laminate with multicolor marking) marked in two different color tones can be obtained.

  In addition, by irradiating the laminate (1) of the present invention with a low-energy laser beam, a marking area of a color derived from a chromatic colorant having a large area is formed. Furthermore, by further irradiating with laser light, the irradiated portion can be marked with white or a color with a reduced color density derived from a chromatic colorant (see FIG. 2). That is, FIG. 2 was formed by further irradiating a laser beam inside the marking portion ((3a)) of a color derived from a chromatic colorant formed by irradiation with a low-energy laser beam. 2 shows a laminate (1) (a laminate with multicolor marking) marked in two different colors having a marking portion (3b) of a color with a reduced color density derived from white or a chromatic colorant. . According to this method, the marking portion (3a) of the color derived from the chromatic colorant and the marking portion (3b) of the color having a reduced color density derived from white or the chromatic colorant are adjacent to each other. Laser marking can be realized. Incidentally, the energy of the laser light irradiated for the second time may be the same as or different from the first time, and is not particularly limited.

When two-color clear marking is obtained by the multicolor laser marking method according to the present invention, it is usually a chromatic colorant that causes low-energy laser light to significantly lose the color derived from the black material. The color of origin may be clear. Moreover, the high energy laser light is so good that the density of the color derived from the chromatic colorant is remarkably lowered.

  When obtaining a clear marking of three or more colors by the color-developing laser marking method according to the present invention, the A layer may be applied to a laminate containing only one kind of chromatic colorant, or the A layer has Although it may be performed on a laminate containing two or more coloring agents, the latter is preferable in that a clearer marking can be easily formed.

  A simple method for obtaining laser beams having different energies is to use laser beams having different wavelengths. For example, when the multicolor laser marking according to the present invention is clearly performed by laser light irradiation having different wavelengths, the difference in wavelength of each laser light is preferably 100 nm or more, more preferably 200 nm or more, and particularly preferably 500 nm. That's it. The upper limit is usually 1,500 nm.

  When the chromatic colorant used in the present invention, that is, the chromatic colorant having an exothermic peak by differential thermal analysis in the temperature range of 360 ° C. or higher and 590 ° C. or lower is used, the chromatic colorant is irradiated with two laser beams having different wavelengths. In order to clearly form a marking of a color derived from a chromatic colorant and a marking of a color having a reduced color density derived from white or a chromatic colorant, a laser beam having a wavelength of 1,064 nm and a wavelength of 532 nm It is preferable to use the laser beam. That is, the color derived from the chromatic colorant was irradiated with the laser beam having a wavelength of 1,064 nm, and the white color or the color having a reduced color density derived from the chromatic colorant was developed by the laser beam irradiation with the wavelength of 532 nm. Suitable for forming clear markings.

  The “color derived from the chromatic colorant” obtained by the laser marking method according to the present invention mainly refers to a color obtained as a result of the disappearance or discoloration of the black material by laser light irradiation. Specifically, (a) the color of the chromatic colorant itself used in the present invention (hereinafter simply referred to as “coloring of the present invention” appears when the influence of the color of the black material is reduced by the disappearance, discoloration, etc. of the black material. (B) The color of the colorant of the present invention is blackish (the color of the colorant of the present invention + the color of the black material, the color of the colorant of the present invention + the color of the black material is changed). Color), (c) a color in which the color tone of the chromatic colorant used in the present invention is changed, and (d) a color in which the above color (c) is blackish.

  Further, the “color having a reduced color density derived from the chromatic colorant” obtained by the laser marking method according to the present invention is the above-mentioned “color having a reduced density of the color derived from the chromatic colorant”. Say. The color is a color obtained as a result of mainly changing the chromatic colorant by laser light irradiation. Specifically, the color of the chromatic colorant is affected by decomposition, scattering, etc. of the chromatic colorant. In addition to the colors that appear as the colors become smaller, colors that change color tone due to discoloration of the chromatic colorant used in the present invention are also included. The “color having a reduced color density derived from the chromatic colorant” is more preferable as it is closer to white because it is easier to distinguish from the “color derived from the chromatic colorant” described above.

  The above-mentioned “white” obtained by the laser marking method according to the present invention is mainly based on the color of the polymer itself contained in the thermoplastic polymer composition (a) for multicolor coloring laser marking used in the present invention. Not only pure white, but also white colors mixed with other colors are included. Furthermore, in addition to this color, when the composition (a) contains titanium black as a black substance, the color derived from the titanium dioxide after being changed to titanium dioxide by irradiation with laser light, or the A mixed color of the color and the color of the polymer, a color derived from a white material or the like blended as necessary, or a mixed color of the color and the color of the polymer. When the polymer contained in the thermoplastic polymer composition for multicolor laser marking (a) is easily foamed by receiving laser light, the color development in the irradiated portion of the high energy laser light is more white. Get higher.

  The whiteness of the above “white” can be evaluated according to JIS K7105. The whiteness means the degree of whiteness of the color, and is evaluated by the reflectance when a certain amount of light is irradiated onto the object. The reflectance can be measured with a hunter whiteness meter or the like. Here, the reflectance varies depending on the type (wavelength, etc.) of light to be irradiated. In the case of a hunter whiteness meter, measurement is performed with blue light that is the three primary colors of light. The whiteness (%) of the white marking obtained in the laminate (1) of the present invention can be represented by the ratio of the intensity of magnesium oxide to the reflected light. Although the whiteness measured by human vision may not always match the whiteness measured by the whiteness meter, the white marking obtained in the laminate (1) of the present invention appears white to human eyes even when the whiteness is low. That's fine. However, the standard of whiteness is preferably 55 to 100%, more preferably 60 to 100%, still more preferably 70 to 100%, and particularly preferably 80 to 100%.

<Laminated body with multicolor laser marking>
The laminate marked with two or more different colors of the present invention (hereinafter also referred to simply as “laminate with multicolor marking of the present invention”) is composed of two or more laser beams having different energies. Is obtained by irradiation.

  The unmarked part (laser beam non-light-receiving part) in the A layer in the multilayer body with multicolor marking of the present invention is composed of a polymer, a chromatic colorant, a black substance and the like. Further, in the light-receiving portion of the low energy laser light (for example, laser light having a wavelength of 1064 nm), the black material has disappeared or changed color (whitening or the like), and the chromatic colorant remains as it is. Furthermore, the light-receiving part of higher energy laser light (for example, laser light having a wavelength of 532 nm) exhibits a color in which the density of the color derived from white or its chromatic colorant is reduced. Vaporized or whitened, and some of the chromatic colorants may remain, but hardly exist. This is because the chromatic colorant is decomposed or scattered by laser light.

  In addition, depending on the kind of polymer which comprises A layer in the laminated body with a multicolor marking of this invention, the marking part may be foaming. In particular, when using a polyacetal resin, a styrene resin using methyl methacrylate as the monomer component, or a rubber-reinforced thermoplastic resin using methyl methacrylate as the monomer component, the foamed marking portion should be used. Can do.

  In the laminate with multicolor marking of the present invention, the marking portion (laser light receiving portion) by laser light may be deformed depending on the type of polymer of the A layer, the type of black substance, and the like. That is, there are cases where foaming, expansion, or the like occurs in the light receiving portion due to laser light irradiation, resulting in a convex portion, or shrinkage or the like, resulting in a concave portion.

  The laminate with multicolor marking of the present invention can be used for various applications. In particular, the B layer in the laminate functions as a laminate layer when bonded to other articles, and can be used as an adhesive coating layer or a fusion layer. Therefore, the laminated body of the present invention can be used as an advertising plate by being attached to the rear part of a driver's seat of a taxi, for example, in addition to a prepaid card.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. In addition, the measuring method of the physical property used in the following examples is as follows. In the examples, “%” and “parts” are based on weight unless otherwise specified.

<1. Test method>
(1) Exothermic peak temperature of chromatic colorant:
About the below-mentioned coloring agent, the exothermic peak temperature was measured by the differential thermal analysis. The measuring apparatus is “TG-DTA320 type (horizontal furnace)” manufactured by Seiko Denshi. 3 mg of the sample was uniformly and densely packed into a dish-shaped container made of aluminum having a diameter of 5 mm and a height of 2.5 mm, and the temperature rising rate was 10 ° C./min, and measurement was performed in air at a flow rate of 200 ml / min. The temperature calibration in the measuring apparatus was performed using indium and tin. The weight was calibrated using a weight at room temperature, and further using calcium oxalate. The exothermic peak temperature was determined by the peak top in the temperature rise curve. The temperature rise curve of the colorant is shown in FIG. 3 for the following colorant C-1. Table 7 shows the results of the exothermic peak temperature of each colorant.

(2) Evaluation method of laminate sheet:
(I) Light transmittance of surface layer:
A film having the same thickness as the surface layer was prepared, and measurement was performed using a spectrophotometer “V-570” manufactured by JASCO Corporation with a light beam having a wavelength of 600 nm.

(Ii) Seat appearance evaluation:
The appearance of a sheet having a width of 1000 mm and a length of 5 m obtained by an extruder was visually observed and evaluated according to the following criteria.

(Iii) Evaluation of chromatic color development:
As a laser marking device, Lofine Basel “Power Line-E” (1064 nm type) is used, and a sheet is formed under the conditions of an output of 24.0 to 30.0 A, a frequency of 4.0 to 13.0 kHz, and a scanning speed of 400 mm / s. The color was developed and visually observed and evaluated according to the following criteria.

(Iv) White color development evaluation:
As a laser marking device, Lofine Basel “Power Line-E” (1064 nm type) is used, and a sheet is formed under the conditions of an output of 24.0 to 30.0 A, a frequency of 4.0 to 13.0 kHz, and a scanning speed of 400 mm / s. The color was developed and visually observed and evaluated according to the following criteria.

(V) Surface smoothness evaluation:
A tactile sensation was evaluated on a sheet having a width of 1000 mm and a length of 5 m obtained by an extruder, and evaluated according to the following criteria.

(Vi) Chemical resistance evaluation:
After 1 ml of ethanol (first grade) was soaked in gauze and the marking portion having white color or black color was reciprocated 200 times with a load of 1 kg, the appearance of the surface layer was visually observed and evaluated according to the following criteria. The time required for one round trip was set to 10 seconds.

(Vi) Method for measuring the dynamic friction coefficient (μd):
Two laminates are stacked on a smooth glass plate by laminating two laminates described later cut to a width of 15 mm and a length of 150 mm, placing a rubber plate thereon, and further placing a load thereon. The contact pressure was 2 g / cm ^2, and the laminate was slid at a speed of 20 mm / min to measure the friction force. The coefficient of friction at the point of sliding 5 mm was defined as the dynamic coefficient of friction (μd). A friction measuring instrument “TR-2” manufactured by Toyo Seiki Co., Ltd. was used as the measuring instrument.

(Vii) Heat sealability:
Two laminates described later are stacked, and both outer surfaces are sandwiched between protective Teflon (registered trademark) sheets having a thickness of 100 μm, and a bar sealer is used under conditions of a temperature of 140 ° C., a pressure of 5 kg / cm ² , and a time of 10 seconds. And heat sealed. Next, the Teflon (registered trademark) sheet was removed, and a strip-shaped sample for measuring the T-shaped peel strength was cut out so that the width of the heat seal portion was 15 mm. The T-shaped peel strength was measured using a tensile tester under the conditions of a temperature of 30 ° C. and a relative humidity of 50% under a distance between chucks of 100 mm and a tensile speed of 300 mm / min. The measurement was repeated 5 times, and the average value was taken as the peel strength.

(Viii) Endurance test evaluation of the laser marking surface:
The laminated body described later is subjected to laser marking treatment, a keystroke test is repeatedly performed 1 million times with a load of 2 kg on the treated surface (length 30 mm, width 30 mm), and the appearance evaluation after the test is visually observed. It was evaluated with.

<3. Materials used>
(A) Materials used for the intermediate layer:
(A-1) Rubber-reinforced acrylic graft copolymer:
Polybutadiene rubber content 30% by weight, styrene content 16% by weight, methyl methacrylate content 49% by weight, acrylonitrile content 5% by weight, graft rate 65%, acetone soluble [η] (Value measured at ° C) 0.48 dl / g rubber reinforced acrylic graft copolymer

(A-2) Acrylic copolymer:
Acrylic copolymer having a styrene content of 21% by weight, a methyl methacrylate content of 72% by weight, an acrylonitrile content of 7% by weight and a [η] (value measured at 30 ° C. using a methyl ethyl ketone solvent) of 0.49 dl / g

(A-3) Styrene copolymer:
An styrene copolymer having a styrene content of 60% by weight and an acrylonitrile content of 40% by weight and a [η] (value measured at 30 ° C. using a methyl ethyl ketone solvent) of 0.52 dl / g

(A-4) Black substance (carbon black):
“Mitsubishi Carbon # 45” manufactured by Mitsubishi Chemical Corporation

(B) Material used for surface layer:
(B-1) Polyethylene terephthalate resin:
"EASTAR PETG Copolymerester 6673" manufactured by Eastman Chemical Company

(B-2) Polyethylene terephthalate resin:
"UNIPET RT523" manufactured by Nihon Unipet Corporation

(B-3) Polycarbonate resin:
“NOVAREX 7022A” manufactured by Mitsubishi Engineering Plastics

(B-4) Acrylic resin:
“Acrypet VH001” manufactured by Mitsubishi Rayon Co., Ltd.

(B-5) White polyethylene terephthalate resin:
A polyethylene terephthalate resin “UNIPET RT523” manufactured by Nippon Unipet Co., Ltd. was mixed with an anatase-type titanium oxide having an average particle size of 0.3 μm in an amount of 3% by weight as titanium oxide, and a twin-screw extruder with an inner diameter of 30 mm was used. It was prepared by melt kneading at a cylinder temperature of 270 ° C.

(C) Chromatic colorant:
The following (C-1) to (C-14) were used as chromatic colorants. These exothermic peak temperatures are shown in Table 8. Moreover, the temperature rising curve of (C-1) is shown in FIG.

(C-1) Copper phthalocyanine pigment:
A β-type copper phthalocyanine pigment (the following formula (30)) having an average secondary particle size of 7.1 μm measured by a laser scattering particle size distribution analyzer was used.

<4. Preparation of pellets for use in the intermediate layer>
(A-1), (A-2), (A-3), (A-4) and (C) shown in Table 9 below were charged into a mixer and mixed. Subsequently, this mixture was melt-kneaded using an extruder with an inner diameter of 50 mm at a cylinder temperature of 190 to 260 ° C. to obtain pellets (1) to (3).

Examples 1-12 and Comparative Examples 1-7:
120mmφ twin screw extruder with vent port (for layer A) and 65mmφ twin screw extruder with vent port (for layer B) for each material of intermediate layer (A layer) and surface layer (B layer) shown in Tables 10-12 Supplied to. Furthermore, in the extruder for layer B, a master batch in which 5% by weight of amorphous silica (average particle size 4 μm) was mixed with the polyethylene terephthalate resin (B-1), and the particle concentration after mixing was layer B. It supplied so that it might become 0.2 weight% with respect to the material to form.

  The temperature of each material of an intermediate | middle layer (A layer) and surface layer (B layer) was 250 degreeC, both were extruded from T-die with a feed block, and it cooled rapidly on the casting drum of temperature 40 degreeC. By controlling the discharge amount of each extruder, a laminate of two types and three layers (B / A / B) having a B layer thickness of 20 μm and an A layer thickness of 260 μm was obtained. Equivalent to 13% of the thickness).

Next, an aqueous solution obtained by diluting a dimethylsiloxane emulsion having a solid content concentration of 30% by weight to 3% by weight was applied to the surface of the above laminate in an amount of ² ml / m ^2, and then dried and fixed. Cut to length to obtain a sheet. The obtained laminate sheet was evaluated by the method described above, and the results are shown in Tables 10-12.

  Examples 1 to 12 are multicolor color-developing laminates according to the present invention, and have target performances in terms of appearance, laser colorability, surface smoothness resistance, and chemical resistance. On the other hand, Comparative Example 1 uses a material that is not specified in the present invention for the surface layer, and is inferior in laser colorability, surface smoothness, chemical resistance, coefficient of dynamic friction, and durability of the laser marking treated surface. Comparative Example 2 uses a material other than that of the present invention for the surface layer, and is inferior in laser color development, surface smoothness, and adhesiveness. Comparative Example 3 uses a material outside the scope of the present invention as the material of the intermediate layer, and is inferior in laser color development. Comparative Examples 4 to 7 use a colorant outside the scope of the invention as a chromatic colorant, and are inferior in laser color development.

It is explanatory drawing which shows the laser marking method in this invention. It is explanatory drawing of an example of the laminated body with a multicolor marking of this invention. It is explanatory drawing of the exothermic peak temperature of a copper phthalocyanine pigment.

Explanation of symbols

1: Laminated body 2: A layer 3a formed with a thermoplastic polymer composition for multicolor laser marking. Chromatic marking part 3b: White marking part 4: B layer formed with a transparent thermoplastic resin.

Claims (8)

A laminate for laser marking in which a B layer is laminated on at least one side of the A layer, and the A layer is marked in two or more different colors by irradiating two or more laser beams having different energies. It is a layer formed of a thermoplastic polymer composition for multicolor laser marking that satisfies the following (1) and (2), and the B layer is a single layer formed of a transparent thermoplastic resin. A layered product for laser marking, wherein the layer has a light transmittance of 70% or more.
(1) A chromatic colorant, a black substance that disappears or discolors itself by receiving laser light, and a thermoplastic polymer are contained in the following proportions.
(2) When the thermoplastic polymer is 100 parts by weight, 0.001 to 3 parts by weight of the chromatic colorant and 0.01 to 2 parts by weight of the black substance are contained.   The laminate according to claim 1, wherein the thermoplastic polymer constituting the thermoplastic polymer composition for multicolor laser marking of the A layer is a copolymer in which a (meth) acrylic acid ester is copolymerized.   The laminate according to claim 2, wherein the copolymer is a rubber-reinforced graft copolymer.   The laminate according to any one of claims 1 to 3, wherein the transparent thermoplastic resin of the B layer is a polyester resin.   The laminate according to any one of claims 1 to 4, wherein the transparent thermoplastic resin of the B layer is subjected to an antiblocking treatment.   The laminate according to claim 5, wherein the polyester resin is a polyester resin in which a ratio of 1,4-cyclohexanedimethanol in all diol components is 15 to 50 mol% with respect to all diol components.   It is a film or a sheet form, The laminated body in any one of Claims 1-6.   The laminate according to any one of claims 1 to 7, wherein a multicolor display is applied by laser light irradiation.