JP2006058869A - Label for laser welding and composite molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin label which can be stuck to a resin molding according to a convenient method without using a adhesive. <P>SOLUTION: A label for laser transmission welding label comprises at least a resin layer and is a resin label for being bonded to a resin molding according to laser welding, wherein the resin layer exhibits a permeability of 20% or higher for laser beams, having an oscillation wavelength within a range of 740 to 1,100 nm wavelength, exhibiting total light transmittance (measured in compliance with ASTM D1003) of 50% or below for visible light, and has light-scattering properties. The resin layer can be constituted of a thermoplastic resin, and the thermoplastic resin may have compatibility with resins constituting the resin molding. The label may be one, capable of concealing the resin molding and may be colored with a colorant, etc. Further, a composite molding such as toner cartridge may be formed, by bonding the label to the resin molding according to laser welding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a label useful for sticking or joining a resin molded product by laser welding, and a composite molded product in which the label is joined (or stuck) to the resin molded product.

  Conventionally, in a molded product such as a resin molded product, a label is used in which printing is performed on one surface and a release paper is bonded to the other surface via an adhesive. However, in such a method, many steps are required for producing the label, and the affixing operation to the molded product requires the release paper to be peeled and aligned, which is very complicated. In addition, in order to recycle a molded product to which a label is attached, it is necessary to peel off the label, which is difficult to recycle.

  Therefore, a molded product that can be easily reused or reused even if a label is attached has been studied. For example, in Japanese Patent Laid-Open No. 2000-43177 (Patent Document 1), a display label made of a material compatible with a molding resin material is attached to a resin molded product main body (such as an upper cover of a toner magazine) with a weak adhesive. A recyclable resin molded product that is detachably attached to (1) is disclosed.

  JP-A-8-340182 (Patent Document 2) discloses a product having a recyclable part made of a thermoplastic resin, made of a thermoplastic resin compatible with the part, and attached to the part. And a decal (sheet-like piece) on which a mark indicating that the part can be reprocessed without peeling from the part is displayed, and a display member (sheet-like member) on which the meaning of the mark is displayed ) Are disclosed. Patent Document 2 discloses that a front door and a decal of a copying machine are bonded by heat fusion or an adhesive.

  In JP-A-10-119169 (Patent Document 3), a recyclable article having a first article and a second article joined to the article via an adhesive, the first article The second article and the second article are composed of mutually compatible thermoplastic resins, and the adhesive strength to the first article is reduced by applying heat and / or electromagnetic waves (such as ultraviolet rays) as the adhesive. A recyclable article using an adhesive having the following is disclosed.

  In Japanese Patent Laid-Open No. 11-109831 (Patent Document 4), a plurality of items such as constituent material names of components constituting the image forming apparatus and reusability as components are selected, and these items are collected together. An image forming apparatus with a recycle display in which a display unit for display is formed in a target part is disclosed. In addition, it is also disclosed that a display unit is formed by attaching a sheet member to a component made of resin. In addition, in patent document 4, there is no description about the detail of the sticking method.

  Japanese Unexamined Patent Publication No. 2000-66607 (Patent Document 5) discloses an external cover for recycling, in which an external cover provided in an apparatus has a peelable transparent film attached to an external surface portion of an external cover base. Yes. Further, in Patent Document 5, the material of the transparent film and the material of the exterior cover base may be compatible with each other, and when an adhesive is used for bonding, the material of the transparent film And the material of the exterior cover base and the adhesive are disclosed to be compatible with each other.

  However, when an adhesive or a pressure-sensitive adhesive is used, it is necessary to peel off the label from the molded product prior to recycling, and the adhesive tends to remain on the surface of the molded product, and the quality of the recycled product also deteriorates. Moreover, when affixing a label by heat fusion or the like, it is difficult to align the same as in the case of using an adhesive, and it may melt to the surrounding resin and impair the appearance of the molded product. It is difficult to apply to shaped molded products.

  Japanese Patent Application Laid-Open No. 2003-181931 (Patent Document 6) discloses a very thin transparent film (infrared ray) which absorbs laser light between adjacent transparent resin members which are non-absorbable with respect to laser light and thermoplastic. A method for laser joining of a thermoplastic transparent resin member is disclosed in which a plurality of transparent resin members are subjected to surface polymerization with an absorbing transparent film) interposed therebetween and welded by irradiating the surface of the outer transparent resin member with laser light. ing. It is also disclosed that a pigment or dye exhibiting absorbency with respect to infrared rays but exhibiting transparency with respect to visible light may be added to the transparent film. However, in Patent Document 6, since a transparent resin member is used, the base cannot be effectively concealed when used as a label. On the other hand, if the label is concealed with the label, the laser beam cannot be transmitted effectively, and the bonding strength tends to be lowered.

JP 2001-198982 A (Patent Document 7) discloses a decorative transparent resin panel provided with a colored layer having a laser light transmittance of 70.0 to 100% and a total light transmittance of 60% or less. Is placed on a colored resin molded product having a laser light transmittance of 0 to 10%, and irradiated with laser light from the colored layer of the decorative transparent resin panel to color the back surface of the decorative transparent resin panel. A method for producing a decorated plastic molded product is disclosed in which a decorative transparent resin panel and a colored resin molded product are welded and integrated by welding the interface of the surface of the resin molded product. However, Patent Document 7 does not describe a label characteristic that can efficiently adjust the degree of hiding the resin molded product as a base (hiding characteristic) without impairing the laser weldability.
JP 2000-43177 A (Claim 1 and paragraph number [0026]) JP-A-8-340182 (Claims 1 and 2, and paragraph numbers [0002], [0026], and [0033]) JP-A-10-119169 (Claim 1, paragraph number [0046]) JP-A-11-109831 (Claims 3 and 8) JP 2000-66607 A (Claims 1, 3 and 6) JP 2003-181931 A (Claims 1 and 2, paragraph number [0018]) JP 2001-199882 A (Claim 1)

  Accordingly, an object of the present invention is to provide a resin label that can be easily bonded to a resin molded product without impairing the laser weldability, and that can effectively conceal the resin molded product as a base, and the resin label. The object is to provide a composite molded product joined to a resin molded product.

  Another object of the present invention is to provide a resin label and a composite molded product that can be firmly bonded to a resin molded product without using an adhesive or the like and have excellent recyclability.

  Still another object of the present invention is to be able to easily join a resin molded product by laser light irradiation regardless of whether or not the resin molded product to be bonded can absorb the laser beam. It is an object of the present invention to provide a resin label and a composite molded product that can effectively conceal the above.

  Another object of the present invention is to form an absorption part capable of absorbing laser light on the surface to be bonded to the label of the resin molded product that is to be bonded, and to effectively conceal the ground by laser light irradiation. An object of the present invention is to provide a composite molded product that can easily bond a resin label to a resin molded product.

  As a result of intensive investigations to achieve the above-mentioned problems, the present inventors have used a resin label having specific transmission characteristics with respect to laser light and visible light. By using laser welding, the function as a label is not impaired. The present invention was completed by finding that it can be easily joined to a resin molded product.

  That is, the laser welding label of the present invention is a resinous label for attaching to a resin molded product by laser welding at least, and in the resin layer, within a wavelength range of 740 to 1100 nm. The transmittance for laser light having an oscillation wavelength is 20% or more (for example, about 20 to 100%), and the total light transmittance for visible light in accordance with ASTM D1003 is 50% or less (for example, about 0 to 50%). It is. The resin layer has light scattering properties and has a haze value of 70% or more in accordance with ASTM D1003.

  The label may have a thickness of about 50 μm to 5 mm. The resin constituting the resin layer may usually be a thermoplastic resin. The thermoplastic resin may have compatibility with the resin constituting the resin molded product.

  The resin layer of the label may be capable of concealing the resin molded product, and is colored chromatic (for example, yellow, orange, red, blue, etc.) or achromatic (for example, white, gray, black, etc.). May be. The color density of the resin layer can be selected as desired. For example, a white colorant and a chromatic colorant can be combined.

  A label constituted by a resin layer alone can transmit laser light, and such a label may be referred to as a laser transmission welding label.

  The label of the present invention may have a printed layer having a display function on the surface. The print layer may be composed of a colorant that is transparent to laser light. In the printed layer, a plurality of such colorants may be combined.

  The label of the present invention may be composed of the resin layer and an absorbing portion that is formed on one surface of the resin layer and can absorb laser light. Such a label can be welded by irradiating it with a laser beam by bringing the absorbent portion side into contact with a resin molded product to be bonded. In addition, the label having the absorbing portion can be easily joined to the resin molded product regardless of the type of the resin molded product, and the range of selection of the resin molded product is widened. In addition, the said absorption part may be an absorption layer which can absorb the laser beam formed in one surface of the resin layer. The thickness of the absorption layer may be about 1 to 40 μm. The absorption layer may be formed of a coating film (coating layer) containing a laser light absorber, for example, formed by application of a coating agent (ink, paint, etc.) containing a laser light absorber. It may be a coating film.

  The present invention also includes a composite molded product in which a resin molded product and the label are joined by laser welding. The resin molded product may be a resin molded product in which an absorption part capable of absorbing laser light is formed on at least a part of a surface (bonded surface or welded surface) to be welded with a label of the resin molded product. Good. When such a resin molded product is used, the label and the resin molded product can be welded by irradiating the laser beam by bringing the absorbing portion side into contact with a laser welding label (for example, a laser transmission welding label). The absorption part may be an absorption layer capable of absorbing laser light formed on a bonded surface of a resin molded product. The thickness of such an absorption layer may be about 1 to 40 μm. The absorption layer may be formed of a coating film (coating layer) containing a laser light absorber, for example, formed by application of a coating agent (ink, paint, etc.) containing a laser light absorber. It may be a coating film.

  The composite molded article is suitable for uses such as consumables that can be recycled, particularly for use in which used products are returned to materials and reused, for example, toner cartridges used in laser printers, small copiers, etc. is there.

  Since the resin label of the present invention is at least composed of a resin layer having specific transmission characteristics with respect to laser light, the resin label can be easily bonded to an object to be bonded without impairing laser weldability. Furthermore, since the resin label has a specific transmission characteristic with respect to visible light, it does not impair the function as a label, and for example, effectively hides a base (bonded body (resin molded product), etc.). You can also In addition, since the label of the present invention can be bonded to the object to be bonded by laser welding, it can be firmly bonded or stuck to the object to be bonded without using an adhesive or the like, and can be recycled. Also excellent. Further, in a label having an absorption part (such as an absorption layer) capable of absorbing laser light on one surface of the resin layer, regardless of whether the resin molded product to be bonded can absorb laser light or not. Using the laser light transmittance of the resin layer and the laser light absorbability of the absorption part, the absorption part side can be brought into contact with the object to be bonded and easily stuck or bonded by laser light irradiation. In addition, since the resin layer has specific transmission characteristics with respect to visible light, it is possible to effectively conceal the base (absorbing part and bonded object).

  Or, for resin molded products where an absorption part (absorption layer) capable of absorbing laser light is formed on the surface with the resin molded product, contact the laser welding label that can effectively conceal the absorption part and the substrate. Thus, it can be easily applied or bonded by laser light irradiation.

[Laser welding label]
The laser welding label of the present invention is composed of at least a resin layer (laser light transmission layer) having specific transmission characteristics for laser light, and may be composed of (i) a resin layer alone, (ii) ) A resin layer and an absorption part (such as an absorption layer) capable of absorbing a laser beam formed on one surface of the resin layer may be used. Moreover, in order to provide a display function (or identification function), at least the surface of the laser welding label may be printed. Such a printed label is also included in the present invention.

(Resin layer)
The resin (or base resin) constituting the resin layer is not particularly limited as long as it can transmit laser light, and various thermoplastic resins can be used. Even a crystalline resin is an amorphous resin. May be. Examples of the thermoplastic resin include styrene resin, acrylic resin (for example, poly (meth) acrylic acid alkyl ester such as polymethyl methacrylate, polyacrylonitrile, etc.), olefin resin (polyethylene, polypropylene, ethylene-propylene copolymer). Olefins such as homo- or copolymers), vinyl resins (vinyl chloride resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, etc.), thermoplastic polyesters system resin (poly C _2-4 alkylene terephthalate, poly C _2-4 alkylene naphthalate, these copolyesters, polyarylate, liquid crystal polyester), polyamide resins (polyamide 6, polyamide 66, polyamide 610, polyamide 11, polyamide 12, polyamide 612, polyamide 6/66, polyamide 6/11, etc.), polycarbonate resins (bisphenol polycarbonates such as bisphenol A polycarbonate, hydrogenated bisphenol polycarbonates, etc.), polyphenylene oxide resins and the like. .

  Examples of the styrene resin include polystyrene (GPPS, etc.), styrene-acrylic copolymer (styrene-methyl methacrylate copolymer, styrene- (meth) acrylic acid copolymer, styrene-acrylonitrile copolymer (AS resin). )), Styrene-diene or olefin copolymer [styrene-butadiene-styrene (SBS) block copolymer, styrene-isoprene-styrene (SIS) block copolymer, etc.], rubber-containing styrene resin [impact resistance , Polystyrene (HIPS), acrylonitrile-butadiene rubber-styrene resin (ABS resin), methyl methacrylate-butadiene rubber-styrene resin (MBS resin), methyl methacrylate-styrene resin (MS resin), and the like.

  Among these thermoplastic resins, from the viewpoint of strength as a label and light scattering properties, crystalline resins (polyamide, crystalline polyester, etc.), non-crystalline resins, polystyrene (GPPS, etc.), rubber reinforced resins (for example, It is preferable to use rubber-containing styrene resin (for example, ABS resin, styrene-diene or olefin copolymer).

  The said thermoplastic resin can be used individually or in combination of 2 or more types. When a plurality of resins are used in combination, the combination of the resins may be the same system or depending on the type of the resin and the absorber constituting the bonded body (or the bonded body), unless the laser weldability and moldability are impaired. A combination of resins of different systems may be used. In addition, it is preferable that resin which comprises a resin layer has compatibility with the resin which comprises the resin molded product which is a to-be-joined body, and / or the resin contained in an absorber.

  The resin constituting the resin layer is not particularly limited as long as it can transmit a laser beam, and may be transparent, translucent, or opaque. Further, the resin may be a resin composition further containing a colorant. Even a transparent resin can effectively function as a label by using a colorant in combination.

  The resin layer of the resin label may be translucent or opaque, and the transmittance for laser light is, for example, 20% or more (for example, about 20 to 100%) depending on the oscillation wavelength of the laser light to be used. I just need it. In this specification, “transmittance to laser light of 20% or more” means that a laser beam selected from laser beams having an oscillation wavelength within a wavelength range of 740 to 1100 nm (preferably wavelengths of 740 to 1064 nm). It is sufficient that the transmittance is 20% or more with respect to the wavelength, and the transmittance is not necessarily 20% or more with respect to the entire wavelength range. The transmittance of the resin layer with respect to laser light is preferably 25% or more (about 25 to 100%), more preferably 30% or more (about 30 to 100%). Moreover, even if the laser light transmittance of the resin layer is about 20 to 70%, the label can be efficiently welded.

  When the resin layer is composed of a resin composition containing the colorant, the colorant may be a chromatic or achromatic colorant that can transmit laser light (or a colorant that is non-absorbable with respect to laser light). Can be used. Examples of the colorant include white dyes and pigments (for example, inorganic pigments such as titanium white, calcium carbonate, zinc oxide, zinc sulfide, and lithopone), yellow pigments (for example, cadmium yellow (cadmium yellow), chrome yellow (chrome yellow ), Zinc chromate, inorganic pigments such as ocher, organic pigments such as Hansa Yellow, Benzidine Yellow, and Pigment Yellow], orange pigments, red pigments [for example, red lip pigments, amber, cadmium red (fire red), red lead (Inorganic pigments such as lead trioxide, Komyotan), organic pigments such as permanent red, lake red, watch chan red, brilliant carmine 6B], blue pigments [eg, bitumen, ultramarine, cobalt blue (tenal blue) Inorganic pigments such as, organic pigments such as phthalocyanine blue], green pigments [eg, chrome green Which inorganic pigments, organic pigments such as phthalocyanine green], azo dyes, azo metal-containing dyes, naphthol azo dyes, azo lake dyes, azomethine dyes, anthraquinone dyes, quinacridone dyes, Dioxazine dyes, diketopyrrolopyrrole dyes, anthrapyridone dyes, isoindolinone dyes, indanthrone dyes, perinone dyes, perylene dyes, indigo dyes, thioindigo Examples thereof include organic dyes such as dyes, quinophthalone dyes, quinoline dyes, benzimidazolone dyes, and triphenylmethane dyes. In addition, as the black colorant, a known or commercially available laser-absorbing black dye / pigment can be used. Such black colorants are available from, for example, “eBINDTW-817OC”, “eBINDTW-8012”, “eBINDTW-8620C”, “eBINDTW-8630C”, “eBINDTW-8400C”, “eBINDTW” from Orient Chemical Industries, Ltd. -8950C "," eBINDTW-8200 "," eBINDTW-8300 "," eBINDTW-8250C ", etc., and can be used preferably.

  As the colorant, the dyes and pigments exemplified above may be used alone, or a plurality of colorants may be used in combination to adjust to a desired color tone. For example, using a subtractive color mixing method, a plurality of colorants having different hues (for example, three primary colors) may be combined to color the resin (for example, colored black), a white colorant, and a chromatic color. It is also possible to combine with other colorants. The colorant may have a light scattering property, and when such a colorant (for example, a pigment such as titanium oxide) is used, the light scattering property can be imparted to the label, and the resin molded product serving as the base is effective. Can also be hidden.

  In addition, the color of the resin layer is not particularly limited, and the base (the resin molded product and / or the absorption part that is a bonded body) may be concealed as necessary. A color that can be clearly distinguished may be employed for the color of the object to be joined, or a similar color may be employed. Such a label may be colored chromatic (for example, yellow, orange, red, blue, etc.) or achromatic (for example, white, gray, black, etc.).

  The ratio of the colorant is not particularly limited, but can be appropriately selected according to the kind of the resin or the colorant, the oscillation wavelength of the laser beam, the color of the bonded body, and the like, for example, 0.0001 with respect to 100 parts by weight of the resin. It may be about 10 to 10 parts by weight, preferably 0.001 to 7 parts by weight, and more preferably about 0.01 to 5 parts by weight.

  Since the resin layer of the resin label effectively conceals the base (resin molded product), the total light transmittance with respect to visible light based on ASTM D1003 is, for example, 50% or less (about 0 to 50%), preferably May be 30% or less (about 0 to 30%), more preferably 20% or less (about 0 to 20%).

  Further, the resin layer of the resin label has a haze value (calculated as diffuse transmittance / total light transmittance, which is a haze value) measured in accordance with ASTM D1003 of 70% or more (for example, 70 to 100). %), Preferably 80% or more (for example, about 80 to 100%), more preferably about 90 to 100%. The resin layer having such a haze value also has a light scattering property, and can effectively conceal the base without impairing the laser weldability.

  If necessary, the resin layer may contain other additives such as a compatibilizer, a flame retardant, a filler (glass fiber, carbon fiber, metal filler, etc.), a stabilizer (antioxidant, etc.), a lubricant, a dispersant, A foaming agent, an antibacterial agent, etc. may be included.

(Absorption part)
The absorbing portion only needs to be able to absorb the laser beam and weld the resin label to the object to be bonded. The absorber for the laser beam is spread or applied to one surface of the resin layer (the laser beam absorber You may form by making it adhere by application | coating etc. of a dispersion liquid or a solution. The absorber is usually a laser light absorber and a resin (in addition to the resin exemplified in the section of the resin layer, a conventional resin used in a coating agent such as an ink or a paint (for example, a ketone resin or a terpene resin) Etc.) in many cases. In a label having such an absorption part, the absorption part side can be brought into contact with a resin molded product, and welding can be performed by laser light irradiation.

  The distribution form of the absorbing portion is not particularly limited, and may be distributed in a uniform or non-uniform layer shape on one surface of the resin layer, or may be wholly or partially on one surface of the resin layer. A distributed distribution may be used. In addition, the absorbing portion may be distributed in a specific shape, for example, a linear shape, a curved shape, a circular shape, a polygonal shape, or the like, and a shape (for example, a plurality of parallel lines, a lattice, etc.) that matches the irradiation position of the laser beam. Shape). Of these dispersed forms, usually, a layered absorber (absorbing layer) is often formed on one surface of the resin layer. The absorption layer should just contain the said laser beam absorber, and can be normally comprised with the resin composition containing the said laser beam absorber and resin (base resin). Further, the absorption layer may be a coating film containing the laser light absorber.

  The laser light absorber can be selected according to the wavelength of the laser light, and an inorganic or organic dye / pigment having absorption in the wavelength region of the laser light can be used. Usually, carbon black (for example, acetylene black, lamp black, thermal black) , Furnace black, channel black, ketjen black, etc.), titanium black, black iron oxide, aniline black and other pigments (black pigments), nigrosine, phthalocyanine, porphyrin, cyanine compounds, perylene, quaterrylene, metal complexes, Dyes such as azo dyes, anthraquinones, squaric acid derivatives, and immonium dyes can be used. These laser light absorbers can be used alone or in combination of two or more. The average particle diameter of the pigment can be selected from a wide range of, for example, about 10 nm to 3 μm (preferably 10 nm to 1 μm). The primary particle size of carbon black may be, for example, about 10 to 100 nm, preferably about 15 to 90 nm. In the absorption layer composed of the resin composition, the ratio of the laser light absorber is 0.1 to 10 parts by weight, preferably 0.3 to 7 parts by weight, more preferably 0, relative to 100 parts by weight of the base resin. It may be about 5 to 5 parts by weight. The absorption layer may contain the laser light absorber as a colorant, and may further contain another colorant (such as an inorganic or organic dye / pigment).

  In the absorption part (absorption layer) constituted by the resin composition, the base resin preferably has compatibility with the resin constituting the joined body and / or the resin constituting the resin layer. Preferred base resins are crystalline resins (polyamide, crystalline polyester, ketone resin, etc.), and noncrystalline resins are polystyrene (GPPS), rubber-reinforced resins (for example, rubber-containing styrene resins such as ABS resin, styrene- Diene or olefin copolymer).

  The thickness of the absorption layer can be selected within a range that does not impair the bondability to the bonded body, and may be, for example, 0.5 to 50 μm, preferably 1 to 40 μm, and more preferably about 2 to 30 μm. The thickness ratio of the absorption layer to the resin layer is, for example, absorption layer / resin layer = 0.001 / 100 to 20/100, preferably 0.005 / 100 to 15/100, more preferably 0.01 / 100 to 10. It may be about / 100.

  Moreover, an absorption part (or absorption layer) may contain the other additive illustrated by the term of the said resin layer as needed.

  In the present invention, the label constituted by the resin layer alone can transmit laser light as a whole label, and can usually be welded to a resin molded product capable of absorbing laser light by laser light irradiation. Further, in a label composed of a resin layer and an absorption part, laser light transmitted through the resin layer is absorbed by the absorption part, and can be joined to a resin molded product to be joined on the absorption part side of the label. . Therefore, the label having the absorbing portion can be easily and efficiently bonded to the bonded object regardless of the laser light absorbability of the bonded object.

  In addition, since the resin label of the present invention has at least a resin layer having specific transmission characteristics with respect to laser light and visible light and having specific light scattering characteristics, the label surface side (viewing side in particular) ), It is possible to achieve both laser weldability and underlying concealment without providing a colored layer.

  The thickness of the resin layer or label (for a label having an absorption layer, the total thickness of the resin layer and the absorption layer) is, for example, 50 μm to 5 mm, preferably 70 μm to 3 mm (for example, 100 μm to 1 mm), more preferably It can be selected from a range of about 150 μm to 1 mm (for example, 510 μm to 1 mm), particularly about 200 to 900 μm (for example, 550 to 900 μm). In the case of a resin label composed of a resin layer alone, the opacity of the label can be adjusted by the thickness of the label (resin layer) as long as it does not inhibit the transmission of laser light.

  The label thickness may be uniform or non-uniform throughout the label. Moreover, the label may have irregularities or holes in part, the label surface may be curved, or at least part of the surface may be inclined. The label is usually in the form of a sheet or film (or plate) in many cases.

  In addition, the shape (planar shape) of the laser welding label is not particularly limited, and for example, a polygonal shape (triangular shape, quadrangular shape, trapezoidal shape, etc.), a circular shape, an elliptical shape, a straight line and It may be various shapes surrounded by a curve (for example, shapes imitating various tangible objects such as block arrows, star shapes, donut shapes, etc.).

  The resin layer (or a single-layer structure label composed of the resin layer alone) and the absorption layer composed of the resin composition have each component (for example, resin, colorant, laser light absorption) tailored to each request. Additives, additives, etc.) are mixed by a conventional mixing method using an extruder, kneader, mixer, roll, etc. (for example, melt kneading), and a conventional molding method such as extrusion molding, injection molding, compression molding, It can usually be obtained by molding into a sheet or film (or plate) by blow molding or the like. Further, the sheet-like molded body may be processed into a desired shape by processing such as die cutting and cutting, if necessary.

  In addition, a resin label having a laminated structure of a resin layer and an absorbent layer is produced by a conventional method for producing a laminated film, for example, a lamination method, a coextrusion method (coextrusion T die molding method, coextrusion circular die molding method, It can be prepared by a method such as an extrusion hollow molding method) or a coating method.

  In the laminating method, the resin layer molded by the molding method and the absorbent layer can be prepared by laminating by a conventional laminating method such as heat lamination or dry lamination.

  In the coextrusion method, the resin composition constituting each layer can be prepared by co-extrusion using a general-purpose die with a feed block or a multi-manifold die. For example, each resin composition is supplied to an extruder. Then, it can be prepared by melting and stirring, joining the resin composition layers in a die, laminating them, and extruding them from the die.

  In the coating method, a coating liquid is prepared by dissolving or suspending a resin composition constituting one of the resin layer and the absorption layer in a solvent, and this coating liquid is molded by the other (for example, the molding method exemplified above). Sheet or film-like resin layer) by conventional casting or coating methods such as roll coater, air knife coater, blade coater, rod coater, bar coater, comma coater, gravure coater, silk screen coater method, etc. It can be prepared by coating and drying. Moreover, you may apply a coating liquid to the surface of the other resin layer by spray coating. Examples of the solvent include aromatic hydrocarbons such as toluene; nitriles such as acetonitrile; amides such as dimethylformamide; sulfoxides such as dimethyl sulfoxide; alcohols (alkanols such as ethanol; aralkyl alcohols such as benzyl alcohol); glycol solvents; An ester solvent; or an organic solvent such as a mixed solvent thereof can be used. Either the resin layer or the absorbent layer may be formed by a coating method, but usually a film or sheet-like resin layer is often coated with a coating solution of the resin composition constituting the absorbent layer.

  In the coating method, a coating film (coating layer) is formed by applying a coating agent (ink and / or paint) containing a laser light absorber to at least a part of one surface of the resin layer. Also good. Such a coating agent is usually a laser light absorber, a conventional component used in inks or paints, for example, a solvent (such as the above-mentioned solvent), a resin component (in addition to the above-exemplified resin, a ketone). Resin, terpene resin, etc.) and additives (organic acids such as oleic acid) are often included.

  Note that characters and images can be printed (including copying and transfer) on at least the surface of the resin label by a conventional method. Moreover, you may form the said character, an image, etc. on the label surface using the coloring agent which can permeate | transmit a laser beam (for example, the coloring agent illustrated by the term of the said resin layer). Moreover, you may make it function as a label by providing an unevenness | corrugation (for example, Braille etc.) etc. on the surface.

(printing)
The printing (printing section) applied to at least the surface of the laser welding label may have a display function (or identification function), and has an identifier (a point, a symbol, a character, a symbol, or a character string) having a specific shape. , Barcode, figure, image, etc.) or simple coloration (coloring having a color classification function, etc.). The printing part may be formed on the entire label surface or a part thereof. In the label having the absorbing portion, the printing portion is formed on at least the front surface (viewing surface) of the label, and the absorbing portion is formed on the back surface (welded surface) of the label.

  The printing part is usually formed in a layer on the label surface, and such a printing part may be referred to as a printing layer. The printing part (or printing layer) can be usually formed by utilizing a conventional printing method such as a label printing method. For example, the printing portion (printing layer) may be formed on the label by pressing the thermal head against the ink ribbon and heating the ink ribbon. The printing part (or printing layer) may be formed on at least the surface of the label prior to laser welding, or may be formed simultaneously with laser welding (for example, the printing part simultaneously with welding by laser light irradiation). May be formed).

  The printing part (printing layer) usually contains chromatic or achromatic colorants (dyes, pigments, compounding colorants, etc.), etc., but is transparent to laser light from the viewpoint of laser weldability. The colorant which has is preferable.

  As the colorant having transparency to laser light, the dyes and pigments exemplified in the section of the resin layer can be used. Such colorants may be used singly, or a combination of a plurality of colorants having transparency to laser light may be used as necessary from the viewpoint of laser light transmittance and display or discrimination.

[Composite molded product]
In the composite molded product of the present invention, a resin molded product that is an object to be bonded and the resin label are bonded by laser welding.

  The resin constituting the resin molded product is not particularly limited, and various thermoplastic resins exemplified in the section of the label can be used. It is preferable to form a resin molded product with a resin compatible with the resin constituting the label. The resin constituting the label and the resin constituting the joined body may be a combination of the same type or the same type of resin, or a combination of alloys (or blends) containing the same type or the same type of resin. Also good.

  The bonded body may contain an absorber for laser light (such as the laser light absorber exemplified in the section of the absorber) depending on the type of label. That is, the joined body to be joined to the label composed of the resin layer alone is only required to absorb the laser beam and be welded to the resin label, and usually (i) an absorbent for the resin and the laser beam. Or (ii) a resin molded body in which an absorption part (such as an absorption layer) capable of absorbing a laser beam is formed on at least a part of the bonded surface. The latter resin molded product may be either laser-absorbing or non-absorbing. Moreover, the to-be-joined body joined with the label comprised by the resin layer and the absorption part (absorption layer) may be any of a laser beam absorptivity and a non-absorbability, and may contain a laser beam absorber. , May not be contained. In addition, the to-be-joined body (or resin or resin composition which comprises a to-be-joined body) may contain the said laser beam absorber as a coloring agent. The distribution form of the laser light absorber in the bonded body is not particularly limited, and may be distributed uniformly throughout the bonded body or may be distributed unevenly (for example, locally distributed on the surface). However, it is often distributed at least on the surface to be joined (or the surface to be welded). In addition, the laser light absorber may be distributed in a uniform or non-uniform layer shape over the entire surface to be bonded, or may be distributed in whole or in part on the surface to be bonded.

  The ratio of the laser light absorber is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight (for example, 0.3 to 4 parts by weight) with respect to 100 parts by weight of the resin constituting the joined body. More preferably, it may be about 0.5 to 3 parts by weight.

  To-be-joined body (or resin or resin composition which comprises to-be-joined body) contains the usual coloring agent (Coloring agents (other coloring agents) other than the said laser beam absorber, for example, commercially available coloring agents etc.). May be. By appropriately selecting the type and ratio of the colorant and / or the laser light absorber, the color tone of the bonded body can be adjusted to a desired color tone. The type of such other colorant is not particularly limited, and various inorganic or organic dyes / pigments used for resin coloring, such as white dyes / pigments (titanium white), yellow dyes / pigments (benzidine yellow, etc.) , Orange dyed pigments (such as Hansa Yellow), red pigments (such as lake red), blue pigments (such as phthalocyanine blue), green pigments (such as phthalocyanine green), etc. May be. The ratio of the colorant is not particularly limited, and may be, for example, about 0.001 to 10 parts by weight, preferably about 0.01 to 5 parts by weight with respect to 100 parts by weight of the resin.

  The absorption part (or absorption layer) can be formed in the same manner as the absorption part described in the section of the label. The thickness of the absorbent layer can also be selected from the same range as the thickness of the absorbent layer exemplified in the section of the label. The absorber may be distributed in a specific shape, for example, a linear shape, a curved shape, a circular shape, a polygonal shape, or the like, or a shape (for example, a plurality of parallel lines, a lattice, etc.) that matches the irradiation position of the laser beam. Shape).

  The resin molded product can be molded by a conventional method, for example, a mixing method and a molding method similar to the method exemplified in the section of the label. The shape of the resin molded product is not particularly limited as long as it has at least a part of a contact surface (such as a flat surface) sufficient to affix or join a resin label, and is a two-dimensional shape (for example, plate shape) or a three-dimensional shape. The target shape may be sufficient.

  There are no particular restrictions on the resin molded product to be joined, such as home or office automation (OA) devices such as computers, word processors, printers, copiers, fax machines, telephones, mobile devices (cell phones, portable information). Equipment (terminals, PDAs, etc.) and home appliances (TVs, VCRs, DVD (Digital Versatile Disc) players, air conditioners, refrigerators, washing machines, etc.) components (housing, case, cover, door, cartridge) (Ink cartridges, toner cartridges, etc.)), as well as various molded products such as automobile parts, household goods, and building materials.

  The composite molded product can be manufactured by bonding a resin molded product as a bonded body and a resin label by laser welding. For example, a composite molded product can be bonded by partially melting the interface between the resin molded product and the resin label by bringing the resin molded product and the resin label into surface contact with each other and irradiating laser light. By bringing the surfaces into close contact and cooling, the two are joined and integrated. In the case of a resin label having an absorption portion, the label and the resin molded product are arranged so that the absorption portion side comes into contact with the resin molded product, laser light is irradiated from the resin layer side, and the absorption portion or its peripheral portion is At least partially melted to join the label and the resin molded product.

  As a laser light source used for laser welding, for example, a solid laser (Nd: YAG excitation, semiconductor laser excitation, etc.), a semiconductor laser (650 to 980 nm), as long as absorption to the resin layer of the resin label is suppressed. Tunable diode lasers (630 to 1550 nm), titanium sapphire lasers (Nd: YAG excitation, 690 to 1000 nm), and the like can be used. Among these laser light sources, a laser light source having an oscillation wavelength in a longer wavelength range (approximately 740 to 1600 nm (for example, about 740 to 1100 nm)) than visible light is usually used.

  In the present invention, since the resin label and the molded product are both joined by laser welding without using an adhesive or the like, it is not necessary to peel the label from the molded product even when it is recycled. Further, the bonding strength can be adjusted by adjusting the intensity of the laser beam, the irradiation time (exposure amount, etc.), and the bonding strength can be reduced with a relatively small exposure amount, for example. Therefore, if necessary, the label can be peeled off from the resin molded product and recycled. Moreover, since the resin label has a specific transmission characteristic with respect to laser light and visible light, the laser weldability is not impaired, and if necessary, the underlying molded product can be concealed as a label. The function is also excellent. In particular, it is optimal to use the toner cartridge as a composite molded product.

  The resin label of the present invention is useful for presenting information by being easily joined to component parts of various devices, resin molded products, and the like. Composite molded products in which resin labels are joined to resin molded products are, for example, household or office automation (OA) equipment such as computers, word processors, printers, copiers, fax machines, telephones, mobile devices, etc. In addition to the components (housing, case, cover, door, cartridge, etc.) constituting various home appliances, it is useful as various resin molded products such as automobile parts, household items, and building materials.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Examples 1 to 12 and Comparative Example 1
(1) Production of labels Sheets A to M having thicknesses shown in Table 1 were produced using the resins and colorants shown in Table 1. Table 1 shows the results of evaluating the total light transmittance, haze value, and laser light transmittance of the obtained sheet. The obtained sheet was cut into a size of 20 mm × 60 mm in length to produce a label.

(2) Laser welding Black impact colored polystyrene (HIPS) (carbon black (CB) content 0.5 wt%) and black colored acrylonitrile-styrene-butadiene (ABS) resin (carbon black (CB) content 0.5 wt%) was used to mold a molded product sample (length 100 mm × width 100 mm × thickness 2 mm). Place the label created in the above step (1) on this molded product sample, and place a transparent glass plate on top of this label as a weight. Fine device 120W laser welder (semiconductor laser, wavelength 940 nm) Both were welded (welding condition I: output 5 W, scanning speed 45 mm / second, welding condition II: output 5 W, scanning speed 15 mm / second). The results are shown in Table 2. The label concealment property was confirmed visually. As the HIPS and ABS resins, the same resins as the HIPS and ABS used in the production of the sheet were used. Moreover, in Examples 1-4, 12 and Comparative Example 1, the said HIPS molded product was used, and in Examples 5-11, the ABS molded product was used.

a) Evaluation of welding ○: No scars or laser scanning traces were observed on the appearance, and they were welded cleanly and accurately. Δ: Scanning marks of the koge and laser were observed on the appearance, but they were welded ×: No welding was observed b ) Weld strip peel test ○: Attempt to peel off label edge by hand, but does not peel off because it is firmly welded ×: Easy to peel off when trying to peel label edge by hand −: Weld C) Concealability ○: The base (and the absorption layer) cannot be seen ×: The base (and the absorption layer) can be seen.

Example 13
(1) Preparation of label with absorbent layer formed On a resin layer having the same composition as sheet C in Table 1 by a multilayer extrusion method, 100 parts by weight of HIPS and carbon black (CB) containing masterbatch (large) A label having a two-layer structure in which an absorption layer having a thickness of 10 μm including 2 parts by weight of PS-M SSC 98H 822D black) manufactured by Nissei Kagaku Kogyo Co., Ltd. was produced. The thickness of the resin layer was set to 339 μm like the sheet C. In this example, the sheet constituting the resin layer is referred to as “sheet C” for convenience. For the total light transmittance, haze value, and laser light transmittance of the resin layer, the transmittance of the sheet C can be referred to.

(2) Laser Welding The label and the object to be joined were welded in the same manner as in Example 3 except that HIPS was used instead of the carbon black-containing HIPS of Example 3 as the object to be joined. Table 3 shows the results of the welding evaluation and the peel test of the weld piece under each condition.

Example 14
(1) Production of label with absorbent layer formed On the sheet C (resin layer) in Table 1, a HIPS film (thickness 20 μm, absorbent layer) containing carbon black (CB) was heat laminated to form a two-layer structure. A label was made.

(2) Laser welding In addition to the carbon black (CB) -containing HIPS of Example 3 being used as the joined body, the label and the joined body were welded in the same manner as in Example 3 except that HIPS was used. Table 3 shows the results of the welding evaluation and the peel test of the weld piece under each condition.

Example 15
(1) Production of Label with Absorbing Layer Formed Polystyrene (GPPS) colored black with 5% by weight of carbon black (CB) was dissolved in toluene to prepare a coating solution. On the label formed of the sheet C, a coating solution was coated with a Mayer bar so that the thickness after drying was 3 μm, and dried to prepare a label having a two-layer structure. In addition, as GPPS, the same resin as GPPS used in preparation of the sheet A or B was used.

(2) Laser welding The label and the object to be bonded were welded in the same manner as in Example 3 except that HIPS was used instead of the carbon black (CB) -containing HIPS of Example 3 as the object to be bonded. Table 3 shows the results of the welding evaluation and the peel test of the weld piece under each condition.

Example 16
(1) Preparation of Coating Agent for Absorbing Layer (Absorbing Ink) All the following components were mixed at 40 ° C., uniformly dissolved, and filtered to prepare a coating agent.

Absorbing ink composition:
Nigrosine dye (manufactured by Orient Chemical Industry Co., Ltd., trade name “Nigrosine Base EX”) 6 parts by weight Ethanol 69 parts by weight Benzyl alcohol 5 parts by weight Oleic acid 10 parts by weight Ketone resin (Akegawa Chemical Industries, Ltd. “Ketone Resin K-” 90 ") 10 parts by weight
(2) Production of label with absorbent layer formed The coating agent (absorbing ink) is applied onto the label formed with sheet C with a bar coder so that the thickness after drying is 10 μm and dried. Thus, a two-layer structure label was produced.

(3) Laser welding The label and the object to be joined were welded in the same manner as in Example 3 except that HIPS was used instead of the carbon black (CB) -containing HIPS of Example 3 as the object to be joined. Table 3 shows the results of the welding evaluation and the peel test of the weld piece under each condition.

Example 17
(1) Manufacture of a bonded body on which an absorbing layer is formed Absorbing ink similar to that in Example 16 on one surface of a bonded body similar to that in Example 10 so that the thickness after drying is 10 μm. The absorbent layer was formed by applying with a coder and drying.

(3) Laser welding As in the case of Example 3, except that the bonded body having the absorption layer is used instead of the carbon black (CB) -containing HIPS of Example 3, the label and the bonded body are bonded. Was welded. The results are shown in Table 3.

Example 18
(1) Preparation of colored ink for printing layer All the following components are mixed at 40 ° C, dissolved uniformly, and filtered to give colored ink (blue ink) that is transparent to laser light. Prepared.

Colored ink composition:
Ditryl guanidine salt of CIAcid Blue 80 (anthraquinone acid dye) 8 parts by weight Ethanol 72 parts by weight Benzyl alcohol 14 parts by weight Terpene resin (“YS Resin TO” manufactured by Yashara Chemical Co., Ltd.) 3 parts by weight Ketone resin (Arakawa Chemical Industries, Ltd.) ) "Ketone resin K-90") 3 parts by weight
(2) Production of label The character string “LABEL” as shown in FIG. 1 was printed on the surface (one surface) of the label formed with the sheet C using the blue ink prepared above by a label printing apparatus. .

(3) Laser welding In the same manner as in Example 3, a molded product sample (length 100 mm × width 100 mm × thickness 2 mm) was formed using HIPS colored in black (carbon black (CB) content 0.5% by weight). . Place the label created in the above step (2) on this molded product sample, and place a transparent glass plate on top of this label as a weight. Fine device 120W laser welder (semiconductor laser, wavelength 940 nm) Was used to irradiate the entire surface of the label with laser light to weld them together (welding condition (i): output 5 W, scanning speed 45 mm / second, welding condition (ii): output 5 W, scanning speed 15 mm / second)). . The results are shown in Table 3. Even after the laser irradiation, the character string “LABEL” on the surface of the label could be visually recognized in vivid blue without burning.

Example 19
(1) Preparation of colored ink for printing layer All the following components are mixed at 40 ° C, dissolved uniformly, and filtered to give colored ink (black ink) that is transparent to laser light. Prepared.

Colored ink composition:
Black transparent colorant (trade name eBIND LTW8170C manufactured by Orient Chemical Co., Ltd.) 5 parts by weight Ethanol 75 parts by weight Benzyl alcohol 14 parts by weight Terpene resin ("YS Resin TO" manufactured by Yasuhara Chemical Co., Ltd.) 3 parts by weight Ketone resin (Arakawa Chemical) Industrial Co., Ltd. “Ketone Resin K-90”) 3 parts by weight
(2) Production of label The character string “LABEL” as shown in FIG. 1 is printed on the surface (one surface) of the label formed with the sheet C using the black ink prepared in the above step (1) by a label printing apparatus. Was printed.

(3) Laser welding In the same manner as in Example 3, a molded product sample (length 100 mm × width 100 mm × thickness 2 mm) was formed using HIPS colored in black (carbon black (CB) content 0.5% by weight). . Place the label created in the above step (1) on this molded product sample, and place a transparent glass plate on top of this label as a weight. Fine device 120W laser welder (semiconductor laser, wavelength 940 nm) Was used to irradiate almost the entire surface of the label with laser light (welding condition (i): output 5 W, scanning speed 45 mm / second, welding condition (ii): output 5 W, scanning speed 15 mm / second). ). The results are shown in Table 3. Even after the laser irradiation, the character string “LABEL” on the surface of the label could be visually recognized in vivid black without burning.

  As is clear from the table, the label of the example was firmly welded to the resin molded product without using an adhesive, and it was difficult to peel the label and the resin molded product by hand. . On the other hand, in the comparative example, the label and the resin molded product were not welded. In addition, when the labels of Examples 1 to 12 and Comparative Example 1 were visually confirmed, the bases were effectively concealed. Moreover, when the label of Examples 13-19 was confirmed visually, both the black absorption layer and the foundation | substrate were effectively concealed.

  (1) In the sheets of Examples and Comparative Examples, the following resins and colorants were used.

(i) Resin Using the white impact-resistant polystyrene (HIPS) shown in Table 1 and, if necessary, polystyrene (GPPS) and a titanium oxide-containing resin master batch, labels having thicknesses shown in the table were produced. Table 1 shows the results of evaluating the total light transmittance, haze value, and laser light transmittance of the obtained label.

(i-1) HIPS: white impact-resistant polystyrene [made by Toyo Styrene Co., Ltd., trade name “E640”]
(i-2) GPPS: Polystyrene [made by Toyo Styrene Co., Ltd., trade name “HRM63C”]
(i-3) ABS: Acrylonitrile-styrene-butadiene resin [manufactured by Nippon A & L Co., Ltd., trade name “ST-55”]
(i-4) PBT: Polybutylene terephthalate [a product manufactured by Wintech Polymer Co., Ltd., “FP700”]
(ii) Colorant
(ii-1) MB1: Titanium oxide-containing resin master batch [manufactured by Sankyo Chemical Industry Co., Ltd., trade name “SCPSM 41919 White (Z)]]
(ii-2) MB2: Titanium oxide-containing resin master batch [manufactured by Polycol Kogyo Co., Ltd., trade name “ESHWMD 17266 0025PM”]
(ii-3) Titanium oxide: manufactured by Ishihara Sangyo Co., Ltd., trade name “R830”
(ii-4) Zinc sulfide: manufactured by SACHTLEBEN CHEMIE, trade name “SACHTOLI TH HD-S”
(ii-5) Yellow pigment (CIPIGMENT YELLOW 93 (disazo dye), manufactured by Dainichi Seika Kogyo Co., Ltd., trade name “CHROMOFINE YELLOW 5930”)
(2) The light transmittance of the label was measured as follows.

(i) Total light transmittance and haze value Based on ASTM D1003, total light transmittance (%) and haze value (%) were measured. As a measuring device, TC-H3DPK manufactured by Nippon Denshoku Industries Co., Ltd. was used.

(ii) Laser beam transmittance A set of 60 φ integration balls for ultraviolet-visible-near infrared region is placed in a spectrophotometer (U-3410, manufactured by Hitachi, Ltd.), and a test piece is set to set a wavelength λ = 808. , 840, 940 and 1064 nm.

FIG. 1 is a top view of the labels produced in Examples 18 and 19.

Claims (16)

  A resin label which is composed of at least a resin layer and is attached to a resin molded product by laser welding, wherein the resin layer has a transmittance of 20 for laser light having an oscillation wavelength in a wavelength range of 740 to 1100 nm. %, The total light transmittance for visible light in accordance with ASTM D1003 is 50% or less, the haze value in accordance with ASTM D1003 is 70% or more, and has a light scattering property.   The label according to claim 1, which has a thickness of 50 μm to 5 mm.   2. The label according to claim 1, wherein the resin constituting the resin layer is a thermoplastic resin.   The label according to claim 1, comprising a resin layer alone.   The label according to claim 1, wherein the resin layer is made of a thermoplastic resin, and the thermoplastic resin is compatible with a resin constituting the resin molded product.   The label according to claim 1, wherein the resin layer is capable of concealing the resin molded product and is colored chromatic or achromatic.   The label according to claim 1, wherein a printed layer having a display function is formed on the surface.   The label according to claim 7, wherein the printed layer is composed of a colorant that is transparent to laser light.   A label formed of a resin layer and an absorption part formed on one surface of the resin layer and capable of absorbing laser light, wherein the absorption part side is brought into contact with a resin molded product, and a laser is formed. The label according to claim 1, which can be welded by light irradiation.   The label according to claim 9, wherein the absorbing portion is an absorbing layer capable of absorbing laser light formed on one surface of the resin layer, and the thickness of the absorbing layer is 1 to 40 μm.   The label according to claim 9 or 10, wherein the absorption part is an absorption layer capable of absorbing laser light, and the absorption layer is formed of a coating film containing a laser light absorber.   A composite molded product in which a resin molded product and the label according to any one of claims 1 to 11 are joined by laser welding.   An absorption part capable of absorbing laser light is formed on at least a part of the surface to be joined of the resin molded product. The absorption part side is brought into contact with the label, and the label and the resin molded product are bonded by laser welding. The composite molded article according to claim 12, which is bonded.   The composite molded article according to claim 13, wherein the absorption part is an absorption layer capable of absorbing laser light, and the thickness of the absorption layer is 1 to 40 μm.   The composite molded article according to claim 13 or 14, wherein the absorption part is an absorption layer capable of absorbing laser light, and the absorption layer is formed of a coating film containing a laser light absorber.   The composite molded article according to any one of claims 12 to 15, wherein the resin molded article is a toner cartridge.

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