JP2016215435A - Intermediate member for laser joining and joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shield light such as light from light source for backlight with a joining part, while sufficiently obtaining joining strength by an intermediate member for laser joining.SOLUTION: An intermediate member for laser joining 40 includes a front joining layer 42, a rear joining layer 43, and a substrate 41 disposed between the front joining layer 42 and the rear joining layer 43. Light transmittance at each of the substrate 41, the front joining layer 42, and the rear joining layer 43 of the intermediate member for laser joining 40 irradiated with light having a wavelength of 400 nm or more and less than 800 nm is 30% or less, and light transmittance at each of the substrate 41, the front joining layer 42, and the rear joining layer 43 of the intermediate member for laser joining 40 irradiated with laser light having a wavelength of 800 nm or more and 1,500 nm or less is 60% or more.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an intermediate member for laser bonding and a bonding method for bonding various members using laser light.

  Conventionally, laser light has been used for joining various members. When joining members using laser light, it is common for one member to be a laser light transmitting member and the other member to be a laser light non-transmitting member, as disclosed in Patent Document 1, for example. As described above, a method is known in which an intermediate member for laser bonding is provided between the first member and the second member, and the first member and the second member are bonded via the intermediate member for laser bonding.

  The intermediate member for laser bonding of Patent Document 1 has a three-layer structure including a first laser light absorption layer on the first member side, a transparent base material, and a second laser light absorption layer on the second member side. . The overall laser light absorption rate of the intermediate member for laser bonding is set to 40% or more and 60% or less, the laser light absorption rate of the first laser light absorption layer is 20% or more, and the laser of the second laser light absorption layer The light absorption rate is set to 20% or more.

  Moreover, it is disclosed that the base material of the intermediate member for laser joining of patent document 1 is an acrylic film, a PET (polyethylene terephthalate) film, or the like.

Japanese Patent Laying-Open No. 2015-6803

  In Patent Document 1, by irradiating laser light, the first laser light absorbing layer on the first member side generates heat, and the second laser light absorbing layer on the second member side also generates heat, and the amount of generated heat is balanced. Thus, the first member and the second member can be favorably joined using the intermediate member for laser joining.

  Moreover, since the base material of the intermediate member for laser joining of patent document 1 is an acrylic film, a PET film, etc., its tensile strength is high, it is excellent in die-cut property, and it is advantageous for manufacture. Furthermore, if the laser beam is irradiated again on the same part as the laser beam irradiated part at the time of bonding, the laser absorption layer can be softened and the bonding strength can be lowered, and this makes it possible to easily peel the first member. It can be easily removed from the first member and the second member without breaking if the intermediate member for laser bonding is picked and pulled with a finger, and is excellent in reworkability.

  By the way, as disclosed in Patent Document 1, when manufacturing a product having a display panel such as a mobile device or a smartphone, the display panel and the casing may be joined by an intermediate member for laser joining. Conceivable. Since the display panel is provided with a backlight, a part of the light (visible light) of the backlight light source reaches an intermediate member for laser bonding interposed between the display panel and the housing. . The intermediate member for laser bonding of Patent Document 1 has a laser light absorption rate of 20% or more in the first and second laser light absorption layers, but the overall laser light absorption rate is 60% or less, so that the backlight It can happen that the light source for light passes through the intermediate member for laser bonding and leaks from the bonded portion between the display panel and the housing, thereby degrading the display performance of the display panel.

  In particular, in the intermediate member for laser bonding disclosed in Patent Document 1, since the substrate is transparent, light leakage from the substrate cannot be avoided, and visible light cannot be blocked.

  The present invention has been made in view of such a point, and the object of the present invention is to provide light such as a light source for a backlight while ensuring sufficient bonding strength by an intermediate member for laser bonding. It is in shading.

  In order to achieve the above object, in the present invention, the visible light transmittance of each of the first bonding layer, the base material, and the second bonding layer of the intermediate member for laser beam bonding is set to 30% or less. The light transmittance was set to 60% or more.

The first invention is
It is disposed between the design layer provided on the bonding surface side of the first member having a wavelength of 800 nm to 1500 nm and having a laser beam transparency, and the second member having a laser beam impermeability of the above wavelength, and In the laser beam bonding intermediate member for bonding the first member and the second member by irradiating laser light of a wavelength,
A first bonding layer disposed adjacent to the first member;
A second bonding layer disposed adjacent to the second member;
A substrate provided between the first bonding layer and the second bonding layer,
Transmittance of light having a wavelength of 400 nm or more and less than 800 nm irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding is 30% or less,
The laser beam having the wavelength irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding has a transmittance of 60% or more.

  According to this configuration, each of the first bonding layer, the base material, and the second bonding layer of the intermediate member for laser bonding absorbs or reflects visible light having a wavelength of 400 nm or more and less than 800 nm, so that the light transmittance in that band is obtained. Is 30% or less, so that visible light having the above wavelength is effectively shielded at the joint portion between the first member and the second member. Therefore, for example, light from a backlight light source or the like is less likely to leak to the outside from the joint portion between the first member and the second member.

  On the other hand, when a laser beam having a wavelength of 800 nm or more and 1500 nm or less is irradiated, the laser beam is transmitted through the laser bonding intermediate member, so that the laser beam sufficiently reaches the laser beam non-transmitting second member. For this reason, for example, when the laser beam bonding intermediate member and the second member are overlapped and the first member is not overlapped and the laser beam is irradiated toward the laser beam bonding intermediate member, the laser beam bonding intermediate member is transmitted. The laser beam reaches the second member, and the second member sufficiently generates heat by the laser beam. This heat heats the second bonding layer of the intermediate member for laser bonding, and the interface between the second bonding layer and the second member. Is sufficiently increased, and the second bonding layer is melted or softened. Therefore, the second bonding layer of the intermediate member for laser bonding is sufficiently adhered to the second member.

  Then, after irradiating laser light for heating the design layer until the predetermined temperature does not exceed the melting and decomposition temperature of the design layer toward the design layer after overlapping the first member and the laser bonding intermediate member, The design layer generates heat. The first bonding layer of the intermediate member for laser bonding is sufficiently heated by the heat of the design layer, the temperature of the interface between the first bonding layer and the first member is sufficiently increased, and the first bonding layer is melted or softened.

  Therefore, by joining the first member and the second member using the intermediate member for laser joining, the joining strength between the first member and the second member is sufficiently increased, and sufficient waterproofness is obtained at the joined portion. It is done.

According to a second invention, in the first invention,
As a constituent component of the substrate, at least one of a urethane resin, a thermoplastic elastomer, and rubber is included.

  According to this configuration, since the cohesive force and elongation of the base material of the intermediate member for laser bonding are increased, even if the intermediate member for laser bonding is peeled off with a finger, it can be easily peeled off without being broken. Suitable.

  In addition, when non-vulcanized rubber is contained, viscoelasticity can be imparted to the base material of the intermediate member for laser bonding, so that it can sufficiently follow short-time deformation. Thereby, even when an impact is applied due to a drop or the like after joining the first member and the second member, the first member and the second member do not peel off.

According to a third invention, in the first or second invention,
It contains at least one of an organic pigment, an inorganic pigment, and a dye as a constituent component.

  According to this configuration, the intermediate member for laser bonding containing at least one of an organic pigment, an inorganic pigment, and a dye effectively absorbs or reflects visible light. Therefore, the intermediate member for laser bonding is excellent in visible light blocking properties. It becomes. On the other hand, the laser joining intermediate member transmits laser light having a wavelength of 800 nm or more and 1500 nm or less, so that sufficient joining strength between the laser joining intermediate member and the second member can be obtained and sufficient at the joining portion. Waterproofness is obtained.

According to a fourth invention, in any one of the first to third inventions,
At least one of the first bonding layer and the second bonding layer has adhesiveness.

  According to this configuration, the intermediate member for laser bonding can be attached to the first member or the second member, so that temporary fixing before bonding can be easily performed.

The fifth invention is:
For laser light bonding between a design layer provided on the bonding surface side of a first member having a laser beam transmittance of 800 nm or more and 1500 nm or less and a second member having a laser beam impermeability of the above wavelength In the joining method of arranging the intermediate member and joining the first member and the second member using the intermediate member for laser beam joining,
A first bonding layer disposed adjacent to the first member;
A second bonding layer disposed adjacent to the second member;
A substrate provided between the first bonding layer and the second bonding layer,
Transmittance of light having a wavelength of 400 nm or more and less than 800 nm irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding is 30% or less,
Laser light bonding wherein the transmittance of laser light having a wavelength of 800 nm or more and 1500 nm or less irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser light bonding is 60% or more. Prepare intermediate members for
After the second bonding layer and the second member of the intermediate member for laser beam bonding are overlapped, the second member is heated by irradiating laser light of the wavelength from the first bonding layer side, After performing the first laser light irradiation for heating the second bonding layer by the heat of the two members,
After the design layer of the first member and the first bonding layer of the intermediate member for laser beam bonding are overlapped, the laser beam having the wavelength is irradiated toward the design layer, and the melting and decomposition temperature of the design layer The design layer is heated to a predetermined temperature that does not exceed, and the second laser light irradiation is performed to heat the first bonding layer with the heat of the design layer.

  According to this configuration, since visible light is effectively blocked at the joint portion between the first member and the second member, light from, for example, a backlight light source is less likely to leak to the outside from the joint portion between the first member and the second member. .

  On the other hand, since the laser joining intermediate member transmits laser light having a wavelength of 800 nm or more and 1500 nm or less, it is possible to sufficiently increase the joining strength by using the heat generated by the second member, and also provide sufficient waterproofing at the joining portion. Sex is obtained.

  According to the first invention, the bonding strength of the first member and the second member can be sufficiently increased to ensure waterproofness, and light such as a light source for backlight can be shielded at the bonding portion. it can.

  According to the second invention, it is possible to provide an intermediate member for laser joining that has high followability to the shape of the first member and the second member, and that has a large cohesive force and elongation. Therefore, rework can also be enabled. . Moreover, since the followability with respect to a deformation | transformation is high, even if it receives an impact, it will not peel.

  According to the third aspect of the invention, visible light can be effectively absorbed or reflected and shielded from light at the joint portion.

  According to the fourth invention, the intermediate member for laser bonding can be easily temporarily fixed.

  According to the fifth invention, as in the first invention, the bonding strength between the first member and the second member can be sufficiently increased, and light such as a light source for a backlight is shielded at the bonding portion. be able to.

It is a perspective view of the joined article concerning an embodiment. It is sectional drawing of the intermediate member for laser joining which concerns on embodiment. It is a figure which shows the point which joins the intermediate member for laser joining to a back side member. It is a figure which shows the point which joins the intermediate member for laser joining to a translucent member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a joined product 1 joined by a joining method using a laser joining intermediate member 40 and a laser beam according to an embodiment of the present invention. The joined product 1 is used, for example, as a cosmetic case, housing or exterior member for electric appliances, a mobile terminal, a mobile phone, a smartphone, or the like, and a translucent member (first member) constituting the front side of the joined product 1. 1 member) 10 and a back side member (second member) 20 constituting the back side are overlapped, and a design layer 30 constituting a part of the light transmissive member 10 is formed on the back surface of the light transmissive member 10. It is provided so as to appear on the front side of the bonded product 1. Although the details will be described later, the translucent member 10 and the back side member 20 are joined by a laser joining intermediate member 40 having a three-layer structure.

  Although not shown, the translucent member 10 is provided with a display screen made up of a liquid crystal display panel or the like. In addition, a light source is provided inside the bonded product 1. Examples of the light source include a backlight light source for a liquid crystal display panel and a transmissive illumination light source for illuminating an operation button provided on a part of the translucent member 10 from the back side. The light source may be provided. The translucent member 10 may have a multilayer structure.

  The back-side member 20 is a plate-like member made of a material having a laser beam impermeability that does not transmit a laser beam having a wavelength of 800 nm to 1500 nm. The back side member 20 may have a multilayer structure. Here, the laser beam transmissivity in the present specification refers to the property of transmitting the laser beam having the above wavelength, and refers to the property of transmitting at least 15% of the laser beam as the heating source. Including those that transmit everything. Examples of the material having such properties include materials such as thin metal oxide films such as plastic, glass, and ITO. On the other hand, laser beam non-transmission means laser beam non-transmission that absorbs or reflects the laser beam having the above wavelength, and partially transmits and / or reflects the laser beam having the above wavelength as a heating source. Means the property of absorbing the rest, including those that absorb all of the laser light. Examples of the material having such properties include materials in which an organic pigment, an inorganic pigment, a dye, a reinforcing glass fiber, and the like are mixed with a resin or rubber in addition to metal and ceramics. In this embodiment, the back side member 20 is comprised with the resin material containing a color pigment and the glass fiber for reinforcement. In the description of this embodiment, laser light having a wavelength of 800 nm or more and 1500 nm or less is also referred to as infrared region laser light.

  The translucent member 10 is a plate-like member made of a material that is colorless and transparent and has a laser beam permeability that allows the laser beam having the above wavelength to pass therethrough. That is, the translucent member 10 transmits the laser beam having the wavelength as the heating source with almost no reflection or absorption, or does not melt even if the laser beam having the wavelength is partially transmitted and / or reflected. The light transmitting member 10 has a property of transmitting the remaining laser light, and the light transmitting member 10 may have a property of transmitting all of the laser light having the above wavelength.

  The translucent member 10 can be made of, for example, a thermoplastic resin, and specifically, polyethylene (HDPE, LDPE, LLDPE, VLDPE, ULDPE, UHDPE, Polyethylene), polypropylene (PP Co-Polymer, PP Homo-Polymer). , PP Ter-Polymer), polycarbonate, polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene resin (ABS), styrene acrylonitrile resin (SAN), K-resin, SBS Resin (SBS block co-polymer), PVDC resin, EVA resin, acrylic resin, butyral resin, silicone resin, polyamide (PA, PA6, PA66, PA46, PA610, PA612, PA6 / 66, PA6 / 12, PA6T, PA12, PA1212, PAMXD6), ethylenetetrafluoroethylene copolymer, liquid crystal polymer, polybutylene terephthalate, polyetheretherketone, polyetherketone, polyetherketoneketone, polymer Examples thereof include reethylene naphthalene, polyethylene terephthalate, polyimide, polyacetal, polyamideimide, polyphenylene ether, polyphenylene oxide, polyphenylene sulfide, polysulfone, polythioethylsulfone, polytetrafluoroethylene, polyethersulfone, and polyetherimide.

  In addition, it includes modified resins in which polar functional groups are chemically bonded. Specifically, acrylic acid-modified olefin resins, maleic acid-modified olefin resins, chloride-modified olefin resins (CPP, CPE), silane-modified olefin resins, ionomer resins. , Nylon-modified olefin resin, epoxy-modified resin, ethylene vinyl alcohol resin (EVOH), ethylene vinyl acetate resin, hot melt adhesive resin, and the like, and may be a mixture or combination of these and the above thermoplastic resins. .

  The translucent member 10 may be a thermoplastic elastomer, specifically, a styrene elastomer, an olefin elastomer, a polyester elastomer, a vinyl chloride elastomer, a polyamide elastomer, a polybutadiene elastomer, an isoprene elastomer, an ion cluster. And amorphous PE elastomer (product example: Mitsui / DuPont Polychemical Himiran), chlorinated PE and amorphous PE elastomer (product example: Miraplane manufactured by Mitsubishi Chemical), fluorine elastomer, polyurethane elastomer And acrylic elastomers.

  The translucent member 10 may be a thermosetting resin, and specifically includes a phenol resin, a urea resin, a melamine resin, an epoxy resin, an unsaturated polyester resin, and the like.

  Moreover, you may comprise the translucent member 10 with the composite resin made by mixing a reinforcing material and a filler with the thermoplastic resin or thermosetting resin mentioned above.

  For the above resins and elastomers, for example, thermal stabilizers, antioxidants, UV stabilizers, conductive agents, nucleating agents, mold release agents, flame retardants, antistatic agents, processing preparations, colored and functional pigments or dyes It is also possible to mix at least one selected from the group consisting of a crosslinking agent, a plasticizer and a vulcanizing agent. When mixing color pigments and dyes, the amount is set such that a predetermined laser beam transparency can be secured.

  The translucent member 10 may be made of, for example, soda lime glass, lead glass, borosilicate glass, or the like in addition to the resin. Moreover, tempered glass, laminated glass, laminated glass, etc. may be sufficient. The translucent member 10 is not limited to being colorless, and may be lightly colored as long as it has translucency so that the design layer 30 can be seen from the front side.

  Although the thickness of the back side member 20 and the translucent member 10 changes with kinds etc. of the joining article 1, it is about 0.1 mm to 3 mm.

  A design layer 30 is provided on the surface on the back side member 20 side which is the back surface of the light transmissive member 10 so that the design appears on the front side of the light transmissive member 10. The design layer 30 is made of a printed coating film formed by attaching an ink containing a dye or a pigment to the back surface of the translucent member 10. For example, when a smartphone, a tablet, or a liquid crystal television is a bonded product 1 The frame has a frame shape that is visible from the front side of the translucent member 10 like a frame portion of a panel for improving the appearance of the display screen.

  As for the curable compound of the ink constituting the design layer 30, for example, acrylate, urethane acrylate, epoxy acrylate, carboxyl group-modified epoxy acrylate, polyester acrylate, unsaturated polyester resin, copolymer acrylate, polyacryl acrylate, alicyclic An epoxy resin, a glycidyl ether epoxy resin, a vinyl ether compound, an oxetane compound, etc. are mentioned.

  Examples of the curable ink include a natural drying curing type, a thermosetting type by baking drying, a two-component reaction curing type using a curing agent, a radiation curing type cured by ultraviolet rays or an electron beam, and lacquer. There is no problem even if it is thermoplastic only under laser irradiation conditions below the melting point. The dye is not particularly limited as long as it has a laser beam impermeability of the above-mentioned wavelength, and may be a natural dye such as Akane or safflower, a synthetic dye such as a reaction, sulfurization or naphthol, or a fluorescent dye. In addition, the pigment may be any pigment that does not transmit laser light having the above wavelength. For example, inorganic pigments such as carbon black and composite oxide pigments, phthalocyanine pigments, azo pigments, lake pigments, Examples thereof include organic pigments such as cyclic pigments, and various pigments having non-transmissibility corresponding to the wavelength of the laser beam having the above wavelength can be used. An elaborate design can be obtained by forming the design layer 30 with a printed coating film. As the printing method, for example, various printing methods such as letterpress printing, intaglio printing, flexographic printing, offset printing, silk printing, gravure printing, laser printing, and ink jet printing can be used.

  Moreover, the design comprised by the design layer 30 has various forms, such as a line, a character, a figure, a symbol, a picture, a gradation pattern, the filling by a single color, or what combined these, for example. Moreover, as thickness of the design layer 30, although it is 1 micrometer or more and 50 micrometers or less, for example, it is not restricted to this range. Moreover, as the laser beam impermeability in the design layer 30, for example, the transmittance of the laser beam having the above wavelength is preferably less than 15%, and the transmittance of the laser beam having a wavelength of 800 nm to 1500 nm is preferably less than 15%. It is more preferable that The design layer 30 hardly transmits visible light.

  The design layer 30 can also be formed by, for example, depositing a vapor deposition film, a film, applying a primer, or the like other than the one formed by a printed coating film as described above. In the case of a deposited film, the design layer 30 is extremely thin. Further, the entire design layer 30 does not have to be laser-opaque, and only a part corresponding to the joint portion between the back member 20 and the translucent member 10 may be laser-opaque.

  A laser bonding intermediate member 40 is provided on the surface of the back side member 20 on the light transmitting member 10 side, and the laser bonding intermediate member 40 is adjacent to the design layer 30.

  As shown in FIG. 2, the intermediate member 40 for laser bonding includes a base material 41 made of a film or a sheet, a front side bonding layer (first bonding layer) 42, and a back side bonding layer (second bonding layer) 43. Multi-layer structure. The front side bonding layer 42 is disposed so as to be adjacent to the translucent member 10. The back side bonding layer 43 is disposed adjacent to the back side member 20. The base material 41 is provided between the front side bonding layer 42 and the back side bonding layer 43. The laser joining intermediate member 40 may have three or more layers.

  The base material 41 of the intermediate member for laser bonding 40 is made of a solid resin material such as a foamed base material that does not have closed cells, for example, a resin material such as urethane, thermoplastic elastomer, rubber, polyethylene terephthalate, polypropylene, and urethane film. For example, it can be set to 10 μm or more and 1000 μm or less.

  It is preferable that at least one of urethane resin, thermoplastic elastomer, and rubber is included as a constituent component of the base material 41. Urethane resins include ether-based, ester-based, polycaprolactone-based, and ether-based (PTMG) -based, and include thermoplastic and thermosetting urethanes. Thermoplastic elastomers include styrene elastomers, olefin elastomers, polyester elastomers, vinyl chloride elastomers, polyamide elastomers, polybutadiene elastomers, isoprene elastomers, ion clusters and amorphous PE elastomers (product examples: Mitsui DuPont Polychemical High Milan), chlorinated PE and amorphous PE elastomer (product example: Miraplane manufactured by Mitsubishi Chemical), fluorine elastomer, polyurethane elastomer, acrylic elastomer and the like. Examples of the rubber include rubbers such as isoprene, butadiene, styrene butadiene, chloroprene, nitrile, polyisobutylene, ethylene propylene, chlorosulfonated polyethylene, acrylic, and epichlorohydrin.

  When manufacturing the base material 41, the method of melt | dissolving the component of the base material 41 in a solvent can be used. In this method, the components of the substrate 41 are dissolved in an appropriate solvent, and the coloring material as a coloring material is also added to the solvent and dissolved or dispersed in the solvent, and this is applied to, for example, a release film or a plate material. Thus, the film-like substrate 41 can be obtained by evaporating the solvent.

  Further, as another method for producing the base material 41, for example, there is a method of obtaining the base material 41 by kneading the dye or pigment and the components of the base material 41 with a twin-screw extruder and extruding it into a sheet shape.

  When a film or base material 41 is obtained by applying a solution or dispersion to a release film or a plate material, the dry coating film has a limit of about 100 μm, but the thickness can be appropriately set when using a twin screw extruder. Therefore, when a thick substrate 41 is necessary, it is preferable to use a twin screw extruder.

  The urethane or rubber may be cured or vulcanized by heat. Examples of the curing agent include isocyanate, peroxide, and sulfur. These are appropriately added to a solvent, and further, a dye or pigment is dissolved or dispersed in the solvent, and this is applied to, for example, a release film or a plate material, or a sheet-like substrate 41 using a twin screw extruder. Or a film-like base material 41 is obtained, and the base material 41 is continuously cured or vulcanized, or heat-cured or vulcanized after being wound up.

  The front side bonding layer 42 of the laser bonding intermediate member 40 is bonded to the translucent member 10, while the back side bonding layer 43 is bonded to the back side member 20. The front side bonding layer 42 and the back side bonding layer 43 are integrated with the base material 41 so as not to peel from the base material 41.

  The material of the front side bonding layer 42 and the back side bonding layer 43 may be the same or different, and the thickness is both set to 100 μm, but the thickness is not limited to this, for example, 50 μm to 200 μm. The following can be set. Further, the thicknesses of the front side bonding layer 42 and the back side bonding layer 43 may be different from each other.

  Hereinafter, the front side bonding layer 42 will be described in detail. The front side bonding layer 42 is made of a hot melt material that is melted by the heat of the design layer 30 heated by the laser beam having the above-mentioned wavelength, and is a polymer substance (tackifier, rubber, elastomer) that exhibits rubber elasticity near room temperature. Among them, those having thermoplasticity are preferred. That is, as the material for the front side bonding layer 42 of the intermediate member 40 for laser bonding, any of the above-described tackifiers, thermoplastic elastomers, non-crosslinked rubbers, and the like can be used. Examples of the imparting agent include rubber, acrylic, urethane, and silicon. Examples of thermoplastic elastomers include styrene elastomers, olefin elastomers, polyester elastomers, vinyl chloride elastomers, polyamide elastomers, polybutadiene elastomers, isoprene elastomers, ion cluster and amorphous PE elastomers (product examples: Mitsui / DuPont Polychemical Himira), chlorinated PE and amorphous PE elastomer (product example: Miraplane manufactured by Mitsubishi Chemical), fluorine elastomer, polyurethane elastomer, acrylic elastomer, and the like.

  Thermoplastic elastomers and non-vulcanized rubbers are also commonly used as a base for rubber-based tackifiers, and are not particularly limited, but can be tackifiers by blending tackifiers, oils, liquid oligomers and the like.

  Further, as the material of the front side bonding layer 42, non-vulcanized rubber can also be used. For example, natural rubber, isoprene rubber, ethylene propylene diene rubber, ethylene propylene rubber, styrene butadiene rubber, butadiene rubber, chlorosulfonation Examples thereof include polyethylene rubber, isoprene rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, nitrile rubber, and hydrogenated nitrile rubber.

  Specific examples of tackifiers include rosin-based tackifier resins such as gum rosin, wood rosin, tall oil rosin and other unmodified rosins (raw rosin), and hydrogenation and disproportionation of these unmodified rosins. In addition to modified rosins modified by polymerization and the like (hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins), various rosin derivatives and the like can be mentioned. Examples of the rosin derivative include rosin ester compounds obtained by esterifying unmodified rosin with alcohols, and modified rosin esters obtained by esterifying modified rosins such as hydrogenated rosin, disproportionated rosin and polymerized rosin with alcohols. Rosin esters such as compounds; Unmodified rosin and modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acids; Unsaturated fatty acid modified rosins; Rosin esters modified with unsaturated fatty acids Unsaturated fatty acid-modified rosin esters; Unmodified rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) Carboxyl groups in unsaturated fatty acid-modified rosins and unsaturated fatty acid-modified rosin esters were reduced. Rosin alcohols; rosins such as unmodified rosin, modified rosin and various rosin derivatives Emissions such (in particular, rosin esters) and the like metal salts of. In addition, as the rosin derivative, a rosin phenol resin obtained by adding phenol to an rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermal polymerization can be used.

  Examples of terpene-based tackifier resins include terpene resins such as α-pinene polymers, β-pinene polymers, dipentene polymers, and modified terpene resins (phenol-modified, aromatic-modified, hydrogenated-modified). And modified terpene resins such as terpene-phenol resins, styrene modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, and the like.

  Examples of hydrocarbon-based tackifying resins include aliphatic hydrocarbon resins [olefins having 4 to 5 carbon atoms and dienes (olefins such as butene-1, isobutylene, pentene-1; butadiene, 1,3-pentadiene, isoprene). Polymers of aliphatic hydrocarbons such as diene etc.], aromatic hydrocarbon resins [vinyl group-containing aromatic hydrocarbons having 8 to 10 carbon atoms (styrene, vinyl toluene, α-methylstyrene) , Indene, methylindene, etc.)], and aliphatic cyclic hydrocarbon resins [so-called “C4 petroleum fraction” and “C5 petroleum fraction” after cyclization and dimerization and polymerization. Hydrocarbon resin, cyclic diene compound (cyclopentadiene, dicyclopentadiene, ethylidene norbornene, dipentene, etc.) polymer or hydrogenated product thereof, aromatic Hydrocarbon resins and alicyclic hydrocarbon resins obtained by hydrogenating aromatic rings of aliphatic / aromatic petroleum resins], aliphatic / aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic -Various hydrocarbon resins such as alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone indene resins and the like can be mentioned. Oil may be selected from paraffinic, naphthenic, and aroma types, which are broadly classified.

  The liquid oligomer is selected from acrylics, styrenes, rubbers such as polyisoprene and butadiene, polyesters, and other high-viscosity polymers having a molecular weight of about several hundred to several thousand. Others are selected from the group consisting of heat stabilizers, antioxidants, UV stabilizers, conductive agents, nucleating agents, mold release agents, flame retardants, antistatic agents, processing preparations, plasticizers and vulcanizing agents as required. It is preferable to use at least one.

  Each of the base material 41, the front-side bonding layer 42, and the back-side bonding layer 43 in the laser bonding intermediate member 40 has a visible light absorption property that absorbs visible light having a wavelength of 400 nm or more and less than 800 nm. Specifically, when visible light having a wavelength of 800 nm or more and 1500 nm or less is irradiated to each of the base material 41, the front side bonding layer 42, and the back side bonding layer 43, the visible light has a transmittance of 30% or less. And blackened.

  Each of the base material 41, the front-side bonding layer 42, and the back-side bonding layer 43 in the laser bonding intermediate member 40 has a laser beam transmittance of 60% or more when irradiated with a laser beam having a wavelength of 800 nm to 1500 nm. The components are determined so that The transmittance of the laser beam of the base material 41 may be different from the transmittance of the laser beam of the front side bonding layer 42 and the back side bonding layer 43. The laser beam transmittance of the front side bonding layer 42 and the back side bonding layer 43 may be higher or lower. The laser beam transmittance of the front side bonding layer 42 and the back side bonding layer 43 can be set to, for example, 80% or more, preferably 90% or more.

  In order to blacken the base material 41, the front side bonding layer 42, and the back side bonding layer 43 with respect to visible light, the following materials are dispersed or dissolved in each material of the base material 41, the front side bonding layer 42, and the back side bonding layer 43. It can be realized by using it alone or in combination.

  It is possible to obtain the base material 41, the front side bonding layer 42, and the back side bonding layer 43 whose light transmittance with a wavelength of 400 nm or more and less than 800 nm is 30% or less and whose light transmittance with a wavelength of 800 nm to 1500 nm is 60% or more. Examples of the organic pigment include infrared transmissive black pigments such as bisbenzofuranone pigments, azomethine pigments, and berylene pigments. Of these, bisbenzofuranone pigments are most preferred.

  Further, the base material 41, the front side bonding layer 42 and the back side bonding layer 43 having a light transmittance of 30% or less at a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more at a wavelength of 800 nm or more and 1500 nm or less are obtained. Colored organic pigments that can be used include CI Pigment Orange 2, 5, 13, 16, 31, 34, etc., CI Pigment Red 1, 2, 3, 4, 5, etc., CI Pigment Green 7, 10, 36, 37, etc. 58, etc., CI Pigment Violet 1, 19, 23, 27, 32 etc., CI Pigment Blue 1, 2, 15, 16, 22 etc. and their derivatives can be mixed and used as black.

  Further, the base material 41, the front side bonding layer 42 and the back side bonding layer 43 having a light transmittance of 30% or less at a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more at a wavelength of 800 nm or more and 1500 nm or less are obtained. Examples of black dyes that can be used include Acid Black 1, 2, 24, 48, which are acid dyes.

  Further, the base material 41, the front side bonding layer 42 and the back side bonding layer 43 having a light transmittance of 30% or less at a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more at a wavelength of 800 nm or more and 1500 nm or less are obtained. The coloring dyes that can be used include chemical structures such as pyrazole azo, anilino azo, triphenylmethane, anthraquinone, anthrapyridone, benzylidene, oxol, pyrazolotriazole azo, pyridone azo, cyanine, Phenothiazine, pyrrolopyrazole, azomethine, xanthene, phthalocyanine, benzopyran, indigo, pyromethene, triarylmethane, azomethine, berylene, perinone, quaterylene, quinophthalone dye, etc. Direct dye, basic dye , Mordant dyes, acid mordant dyes, azoic dyes, disperse dyes, oil soluble dyes, food dyes and their derivatives can be used as a mixture of two or more thereof black.

  Since the infrared laser beam having the above wavelength is long, 100 nm to 500 nm bismuth sulfide powder, 5 nm to 50 nm silver or tin, or an alloy thereof is used as the base material 41 and the front side bonding layer. It can add to the component of 42 and the back side joining layer 43, and the base material 41, the front side joining layer 42, and the back side joining layer 43 can be blackened with respect to a laser beam. Moreover, an organic pigment and a dye can be used in combination, and at least one of an inorganic pigment, an organic pigment and a dye is contained as a constituent component to obtain the base material 41, the front side bonding layer 42 and the back side bonding layer 43. be able to.

  The base material 41, the front-side bonding layer 42, and the back-side bonding layer 43 in the laser bonding intermediate member 40 reflect visible light so that the transmittance of light having a wavelength of 400 nm or more and less than 800 nm is 30% or less. Good. In order to make white having visible light reflectivity, the following materials are dispersed or dissolved in the materials of the base material 41, the front side bonding layer 42, and the back side bonding layer 43, and used alone or in combination. Can be realized.

  Obtaining a substrate 41, a front side bonding layer 42 and a back side bonding layer 43 having a light transmittance of 30% or less at a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more at a wavelength of 800 nm or more and 1500 nm or less; The white inorganic pigment that can be used is an inorganic pigment that is less susceptible to Rayleigh scattering and Mie scattering of infrared rays and reflects visible light of 400 nm or more and less than 800 nm, that is, a diameter of 100 nm to 400 nm that is a particle diameter that is 1/2 or less of the wavelength of infrared rays. Inorganic pigments containing titanium dioxide particles, magnesium oxide particles, barium sulfate particles, basic lead carbonate particles, zinc oxide particles, and the like. These inorganic pigments can be whitened by adding and dispersing in a solvent.

  The visible light transmittance of the base material 41, the front side bonding layer 42 and the back side bonding layer 43 in the intermediate member 40 for laser bonding is preferably 30% or less, more preferably 20% or less, as described above at a wavelength of 400 nm or more and less than 800 nm. . If the visible light transmittance of the laser joining intermediate member 40 is higher than 30%, the light of the backlight source inside the joined product 1 leaks from the joined portion of the translucent member 10 and the back member 20, and the liquid crystal display panel or the like However, if the visible light transmittance is 30% or less, the intermediate member 40 for laser bonding until the light from the light source inside the bonded product 1 cannot be confirmed by the user from the outside. Therefore, the display quality of the display screen is improved.

  As described above, the laser light transmittance of the base material 41, the front side bonding layer 42 and the back side bonding layer 43 in the intermediate member 40 for laser bonding is preferably 60% or more, more preferably 80% at a wavelength of 800 nm to 1500 nm. That's it. When the laser beam transmittance is less than 60%, most of the laser beam is absorbed by the laser bonding intermediate member 40, and the laser beam does not sufficiently reach the second member 20 during bonding, which will be described later. Although the laser bonding intermediate member 40 (the back side bonding layer 43) at the part in contact with the second member 20 is not sufficiently melted or softened, it is not preferable. However, by setting the amount to 60% or more, the laser beam is sufficient for the second member 20 The amount of heat generated by the second member 20 can be sufficiently secured. Thereby, since the back side joining layer 43 of the intermediate member 40 for laser joining melt | dissolves or softens sufficiently, joining strength can be raised.

  In order to disperse the organic or inorganic pigment particles in the material of the base material 41, the front side bonding layer 42 and the back side bonding layer 43 in the laser bonding intermediate member 40, a general bead mill, three roll mill, colloid mill, high-speed rotation A mill or the like can be used. In particular, in order to make infrared rays less susceptible to Rayleigh scattering and Mie scattering, it is necessary to monodisperse particles having a small particle diameter in a solvent as much as possible. In order to help the dispersion of the particles to obtain a stable dispersion state, a surfactant, a polymer resin, or the like can be used as a protective colloid. Moreover, when using a dye, it can be used by dissolving the dye in an appropriate solvent.

  The amount of pigment or dye added varies depending on the color material, but can be adjusted so that the light transmittance with a wavelength of 400 nm or more and less than 800 nm is 30% or less and the light transmittance with a wavelength of 800 nm or more and 1500 nm or less is 60% or more. Good.

  The melting temperature of the front side bonding layer 42 of the intermediate member 40 for laser bonding is set lower than the melting temperature and the decomposition temperature of the design layer 30.

  In the case where an adhesive or non-vulcanized rubber is used as the material for the front side bonding layer 42 of the intermediate member 40 for laser bonding, it is thermoplastic because it avoids a decrease in adhesion due to laser light. It is preferable.

  The front side bonding layer 42 and the back side bonding layer 43 of the laser bonding intermediate member 40 contain a tackifier. The tackifier may be contained only in the front side joining layer 42, or may be contained only in the back side joining layer 43 or both. The tackifier may not be contained in the front side bonding layer 42 and the back side bonding layer 43. Examples of the tackifier include those described above.

  By including the tackifier in the back side bonding layer 43, the surface on the back side member 20 side of the intermediate member 40 for laser bonding has adhesiveness. Moreover, the surface by the side of the translucent member 10 of the intermediate member 40 for laser joining has adhesiveness by including the tackifier in the front side joining layer 42. Therefore, the laser joining intermediate member 40 adheres to the back side member 20 and the translucent member 10. The adhesive strength of the laser joining intermediate member 40 is set so that the adhesive strength of the SUS304 plate measured on the basis of 10.4 of JIS Z0237 is 0.1 N / 25 mm or more.

  The resin composition of the front side bonding layer 42 and the design layer 30 of the intermediate member 40 for laser bonding is preferable because the closer the SP value (solubility parameter), the better the compatibility and the higher the bonding strength between them, and the back side bonding layer 43 and the back side. The closer the SP value of the resin composition of the member 20, the better the compatibility and the higher the bonding strength between them.

  Next, the manufacturing procedure of the joined product 1 will be described. First, the design layer 30 is formed on the back surface of the translucent member 10. In this step, colored ink containing a pigment is attached to the back surface of the translucent member 10 by a printing machine or the like.

  When the design layer 30 is a vapor deposition film, a vapor deposition device such as a metal is vapor deposited on the back surface of the translucent member 10 by a vapor deposition apparatus. When the design layer 30 is a film, the film is attached to the back surface of the translucent member 10. Furthermore, when the design layer 30 is used as a primer, the primer is applied to the back surface of the translucent member 10.

  The above-mentioned process is a process of providing the laser light non-transmitting design layer 30 on the translucent member 10 so that the design appears on the front side of the translucent member 10.

  In addition, the back member 20 may be irradiated with, for example, UV (ultraviolet light), EB (electron beam), ozone, or the like. By doing so, the surface of the back-side member 20 is more activated, and the adhesive force of the laser joining intermediate member 40 after the laser light irradiation can be improved.

  On the other hand, the base material 41 of the intermediate member 40 for laser bonding is applied by drying the solution or dispersion obtained as described above on a release film, a plate material or the like, or extruded using a twin screw extruder. Can be obtained. By laminating and integrating the front side bonding layer 42 and the back side bonding layer 43 on the front and back surfaces of the base material 41, the laser bonding intermediate member 40 is obtained. And the intermediate member 40 for laser joining obtained can be processed into a desired shape by die-cutting.

  Next, as shown in FIG. 3, the laser bonding intermediate member 40 is overlaid on the back side member 20 so that the back side bonding layer 43 of the laser bonding intermediate member 40 overlaps the front side of the back side member 20. At this time, since the back side bonding layer 43 of the intermediate member for laser bonding 40 has adhesiveness, the intermediate member for laser bonding 40 is temporarily fixed to the back side member 20, and the position of the intermediate member for laser bonding 40 Deviation is suppressed.

  Thereafter, as shown in FIG. 3, pressure is applied to the laser bonding intermediate member 40 with a transparent glass 100 with a separator or the like, and laser light L is emitted from the front bonding layer 42 side of the laser bonding intermediate member 40 to the laser bonding intermediate member. The member 40 is irradiated. This is the first laser light irradiation. As a device for irradiating the laser beam L, a known device can be used. As the type of the laser beam L, for example, any of a gas laser, a solid laser, a semiconductor laser, and the like may be used. The type of the laser beam L is not limited, but it is necessary to have a wavelength in an infrared region of 800 nm to 1500 nm. The type of the laser beam L can be appropriately selected according to the material, thickness, and the like of the back side member 20. Further, the laser beam L may be composed of one wavelength, or may have two or more wavelengths.

  Since the front side bonding layer 42, the base material 41, and the back side bonding layer 43 in the laser bonding intermediate member 40 have a light transmittance of 60% or more at a wavelength of 800 nm or more and 1500 nm or less, the laser light L passes through the laser bonding intermediate member 40. It penetrates and reaches the back member 20 and is absorbed. The back side member 20 that has absorbed the laser light L generates heat.

  The back side bonding layer 43 adjacent to the back side member 20 is heated most by the heat of the back side member 20 and melts or softens, and deforms and adheres along the surface of the back side member 20. Bonded to the back member 20. In FIG. 3, a portion indicated by a white circle is a portion mainly heated by the laser light L.

  Since the back side member 20 does not have the design layer 30 and there is no fear of melting or decomposition of the design layer 30, the output of the laser light L at the time of the first laser light irradiation can be set to be strong. Thereby, the back side joining layer 43 can be reliably melted or softened.

  Then, the transparent glass 100 with a separator is peeled off from the intermediate member 40 for laser joining, and the translucent member 10 is piled up on the front side joining layer 42 of the intermediate member 40 for laser joining as shown in FIG. At this time, since the front side bonding layer 42 of the intermediate member 40 for laser bonding has adhesiveness, it is possible to suppress misalignment between the light transmitting member 10 and the back side member 20 without clamping them.

  In addition, you may clamp the translucent member 10 and the back side member 20 in the thickness direction, and can suppress expansion | swelling of the translucent member 10 and the back side member 20 by the heat_generation | fever when the laser beam L is irradiated by clamping. In addition, since the generation of bubbles between the translucent member 10 and the back side member 20 can be suppressed, the reliability of bonding can be further improved.

  Then, as shown in FIG. 4, the laser beam L is irradiated toward the design layer 30 from the translucent member 10 side. This is the second laser light irradiation. The second laser beam irradiation can be performed with the same apparatus as the first laser beam irradiation. The output of the laser beam L for the second laser beam irradiation is preferably lower than the output of the laser beam L for the first laser beam irradiation, for example, about several W. The output of the laser light L at the time of the second laser light irradiation may be an output that does not cause the design layer 30 to melt or decompose by the laser light L that has passed through the translucent member 10 and reached the design layer 30. Further, the scanning speed of the laser beam L is also set to a speed at which the design layer 30 does not melt or decompose. When the joining range is wider than the irradiation diameter of the laser beam L, the laser beam L is irradiated while moving the laser light source or the object to be joined (the back member 20, the intermediate member 40, and the translucent member 10) as necessary. You may go. Moreover, the focal diameter of the laser beam L can be set wide to widen the joining range.

  The irradiated laser light L passes through the translucent member 10 and reaches the design layer 30. The laser beam L that has reached the design layer 30 is absorbed by the design layer 30 and the design layer 30 is heated. Since the output of the laser beam L is set to a low output as described above, the temperature of the design layer 30 is a temperature that does not exceed the melting or decomposition temperature of the design layer 30. In FIG. 4, a part indicated by a white circle is a part mainly heated by the laser beam L.

  The heat of the design layer 30 is transmitted to the adjacent intermediate member 40 for laser bonding. The front side bonding layer 42 of the laser bonding intermediate member 40 is heated until it reaches the melting temperature, and is melted or softened. When the front side bonding layer 42 is melted or softened, the front side bonding layer 42 is brought into close contact with the design layer 30 of the translucent member 10 and bonded. At this time, since the output of the laser beam L is set as described above, the design layer 10 does not melt or decompose.

  Part of the laser beam L (a few percent of the irradiated laser beam L) may reach the back member 20. The slight laser light L that has passed through the design layer 30 reaches the laser joining intermediate member 40. Since the back-side member 20 generates heat, the entire laser bonding intermediate member 40 is melted or softened, and is further in close contact so that the laser beam L can be used effectively.

  As described above, according to the bonding method according to the present embodiment, the laser beam L at the time of the second laser beam irradiation can be a low output of about several W, so that the translucent member 10 is damaged (burned or deformed) by heat. Can be suppressed. Therefore, the application of this bonding method is wide.

  And after the irradiation of the laser beam L is complete | finished, the intermediate member 40 for laser joining is cooled. Thereby, the intermediate member 40 for laser joining is solidified, the back side member 20 and the translucent member 10 are joined, and the joined article 1 is obtained. When the joined product 1 is viewed from the front side of the translucent member 10, the design of the design layer 30 can be seen in the back through the translucent member 10, and the design is deepened. Since the design layer 30 is not dissolved, the appearance is good.

  Moreover, when joining the translucent member 10 and the back side member 20 by irradiation of the laser beam L, it receives a thermal cycle of being cooled after being heated. At this time, stress may be generated at the bonding interface due to a difference in linear expansion coefficient between the translucent member 10 and the back member 20. In contrast, since the laser bonding intermediate member 40 contains an adhesive, urethane, rubber, elastomer, or the like, the stress at the bonding interface can be relaxed by deformation. As a result, it is possible to prevent a reduction in bonding strength and peeling. And even if it receives impacts, such as dropping, the translucent member 10 does not peel off.

  Further, in the obtained bonded product 1, stress may be generated at the bonding interface between the translucent member 10 and the back side member 20 due to thermal stress or mechanical force applied during use. The stress can be relieved by the presence of the intermediate member 40 for laser bonding. Therefore, a predetermined bonding strength can be maintained even when the bonded product 1 is used over a long period of time. Furthermore, since the solid base material 41 having a high density and having no closed cells, such as a foam base material, is used as the base material 41 of the laser joining intermediate member 40, the punchability is good. Further, the closed area is not die-cut to reduce the adhesion area and the waterproofness is not lowered. By using the solid base material 41, since the joining force is also high, joining of a punched product with a narrow line width, that is, so-called narrow frame joining can be realized. And since the intermediate member 40 for laser joining has the high light-shielding property with respect to visible light, even if there exists a light source inside the joining article 1, the light leak from a joining part can be eliminated, implement | achieving a narrow frame.

  As explained above, according to the joining method according to this embodiment, after joining the laser joining intermediate member 40 to the back-side member 20 by the first laser light irradiation, the translucent member 10 is made into the laser joining intermediate member 40. The second laser beam irradiation is repeated, and the design layer 30 is heated until the design layer 30 reaches a predetermined temperature that does not exceed the temperature at which the design layer 30 melts and decomposes so that the laser joining intermediate member 40 and the translucent member 10 are joined. I have to. Thereby, when the design layer 30 is interposed between the translucent member 10 and the back side member 20, the bonding strength between the translucent member 10 and the back side member 20 is sufficient while avoiding melting and decomposition of the design layer 30. Can be increased.

  Further, since the laser joining intermediate member 40 is adhered to the translucent member 10 and the back member 20 before the laser beam L is irradiated, the translucent member 10 and the back member 20 even when temporary fixing or the like is difficult. Can be reliably joined.

  Furthermore, since the laser joining intermediate member 40 is a hot melt material, the design layer 30 and the back side member 20 are sufficiently familiar when irradiated with the laser light L, and a strong adhesive strength is obtained.

  Further, the laser joining intermediate member 40 may be simply softened without being melted or decomposed by the heat of the design layer 30. This can be done by changing the output of the laser beam or the material of the intermediate member 40 for laser bonding. Since the intermediate member 40 can be brought into close contact with the back-side member 20 and the translucent member 10 also by softening the intermediate member 40 for laser bonding, it can be reliably bonded.

  Moreover, you may comprise the intermediate member 40 for laser joining with an adhesive tape. In this case, it is possible to suppress the presence of air bubbles at the joint portion by softening and closely contacting the intermediate member 40, and airtightness and watertightness are improved. In particular, in an adhesive tape having a narrow frame width, the effect of improving airtightness and watertightness is remarkable.

  Furthermore, even when light is generated inside the bonded product 1 such as a backlight light source, it is possible to obtain the bonded product 1 with no light leakage from the bonded portion, high display quality, and high design.

  Moreover, the joining method concerning this invention is applicable when manufacturing various joining goods besides cosmetics cases, housing use, or exterior members for electrical products such as smartphones, mobile devices, and liquid crystal televisions.

  Examples of the present invention will be described below, but the present invention is not construed as being limited to the examples.

(Preparation of base material)
A method for producing three types of base materials (first to third base materials) of the intermediate member for laser bonding will be described.

1. Production of first base material Toughtec M-1913 (SEBS styrene / ethylene / butylene / styrene block polymer) manufactured by Asahi Kasei Chemicals Co., Ltd. as a hydrogenated styrene thermoplastic elastomer is added to toluene as a solvent so that the solid content is 50%. Dissolved. To this resin solution, 0.7% by weight of the dye Acid Black 2 made by Service Chemical Inc. was added and dissolved sufficiently to obtain a black solution.

  The black solution is applied to a 38 μm-thick PET (polyethylene terephthalate) film (separator) that has been subjected to mold release treatment with an applicator to a dry film thickness of 40 μm, and dried to form a sheet-like substrate made of a black thermoplastic elastomer. A material (first base material) was obtained.

2. Preparation of the second base material After adding 10.0% by weight of the black pigment BASF IRGAPOR BK to toluene and dispersing it in the solution by hand, using the ultra-spec mill UAM-015 manufactured by Beads Mill Kogyo Co., Ltd. The fine dispersion was sufficiently performed to obtain a black pigment dispersion. Then, a black pigment dispersion and a curing agent are added to Pandex GW-1340 made by two-component curable solventless urethane DIC Corporation so that the pigment concentration is 2.0% by weight, and the black pigment is sufficiently dispersed. Was stirred as such. The separator was coated with an applicator so that the dried film was 200 μm, and heated for 1 hour with a dryer at 100 ° C. to obtain a sheet-like substrate made of black urethane.

3. Production of Third Base Material NBR JSR N2395V (acrylonitrile / butadiene copolymer rubber) manufactured by JSR Corporation and white pigment CR-58 rutile titanium dioxide manufactured by Ishihara Sangyo Co., Ltd. Particle size 0.28 μm 10.0% by weight, 0.5% by weight of sulfur was sufficiently kneaded with three rolls. This kneaded dough was placed in a stainless steel plate mold with a 300 μm spacer in between and heated at 150 ° C. for 30 minutes to obtain a vulcanized sheet-like substrate having a film thickness of 300 μm.

(Preparation of bonding layer)
Styrene / Butagen / Styrene Copolymer SBS (Kraton D-1118) 56 parts by weight, Styrene / Butagen / Styrene Copolymer (JSR TR2601) 44 parts by weight and terpene phenol resin (Yasuhara Chemical Co. YS Polystar T-115) 50 parts by weight, oil (Kuraray Co., Ltd. LBR-305) 10 parts by weight, antioxidant (Ciba Japan Co., Ltd. Irganox 1010) 1 part by weight dissolved in toluene to obtain a solid content of 40 A weight percent adhesive solution was prepared.

  0.7% by weight of a dye Acid Black 2 made by Service Chemical Inc. was added to the pressure-sensitive adhesive solution and dissolved sufficiently to obtain a black solution. And the black solution was apply | coated to the separator so that it might become a dry film thickness of 100 micrometers using the applicator, and the joining layer was obtained.

Example 1
Preparation of intermediate member for laser beam bonding A bonding layer with a separator attached to both surfaces of the first base material (thermoplastic elastomer base material) is bonded to the first base material, the front side bonding layer, and the back side bonding layer. A laminated intermediate member for laser beam bonding was obtained. The thickness of the bonding layer is as shown in Table 1.

  This laser beam bonding intermediate member was die-cut with a width of 0.5 mm so as to coincide with the design layer of the smartphone panel (translucent member), that is, the outer periphery of the so-called frame portion.

  Next, the separator of the back side joining layer was peeled off, and the back side joining layer was laminated on the black smartphone case (back side member).

  The separator of the front side bonding layer was left as it was, and a colorless and transparent glass plate having the same size as the separator was overlaid on the separator. Then, while pressing the glass plate, a semiconductor laser having a wavelength of 940 nm and a focal diameter of φ1.6 mm was irradiated toward the intermediate member for laser beam bonding under the condition of an output of 5.0 W 10 mm / sec.

  No change such as scorching or foaming was observed in the intermediate member for laser beam bonding, and the intermediate member for laser beam bonding and the casing were bonded with a sufficient bonding force.

  This is because infrared laser light passes through the intermediate member for laser light bonding and reaches the surface of the housing, the surface of the housing sufficiently generates heat, and the back side bonding layer of the intermediate member for laser light bonding that is in contact with the housing is softened or This is because it melted and adhered to the surface of the housing without any gap.

  Next, the separator of the front side bonding layer was peeled off, and the panel was overlapped and fixed so that the intermediate member for laser beam bonding and the frame portion overlapped thereon. A colorless and transparent glass plate of the same size as the panel is stacked on the panel, and the same laser beam as above is used while pressing the glass plate. The laser beam is applied to the frame under the conditions of 3.0 W and 10 mm / sec. Was irradiated. The intermediate member for laser beam joining and the panel were joined with sufficient joining force. Even if the submergence test was conducted for 30 minutes at a depth of 1 m, water did not enter the smartphone.

  Moreover, although the smart phone was dropped from the height of 1.5 m, the panel did not peel from the casing. This is because the design layer absorbs the laser beam and generates heat, and the front side bonding layer of the intermediate member for laser beam bonding that touches the panel is softened or melted so that it adheres to the panel without any gaps, and the impact energy because the base material is flexible. This is due to the fact that can be converted into heat energy.

  Next, the smartphone was turned on in a dark room and observed for light leakage. No light leakage of the backlight from the gap between the panel and the case was observed, and a good smartphone screen was obtained. This is because the dye of the base material, front side bonding layer and back side bonding layer of the intermediate member for laser beam bonding selectively absorbed visible light.

(Example 2)
Example 2 is different from Example 1 in that the base material of the intermediate member for laser bonding is the second base material (urethane base material). The front side bonding layer, the back side bonding layer, and the laser light irradiation procedure The test procedure is the same as in Example 1. The thickness of the bonding layer is as shown in Table 1.

  Even in the case of the intermediate member for laser bonding having the second base material, sufficient bonding force was obtained, and water did not enter the smartphone even when the immersion test was performed at a water depth of 1 m for 30 minutes. Moreover, although the smart phone was dropped from the height of 1.5 m, the panel did not peel from the casing. This is due to the fact that the front side bonding layer of the intermediate member for laser beam bonding in contact with the panel was softened or melted and adhered closely to the panel, and that the impact energy could be converted into thermal energy because the base material was flexible. It is.

Next, the smartphone was turned on in a dark room and observed for light leakage. No light leakage of the backlight from the gap between the panel and the case was observed, and a good smartphone screen was obtained.
This is because the dye of the bonding layer and the pigment of the base material selectively absorbed visible light.

Example 3
Example 3 is different from Example 1 in that the base material of the intermediate member for laser bonding is the third base material (rubber base material). The front side bonding layer, the back side bonding layer, and the laser light irradiation procedure The experimental procedure is the same as in Example 1. The thickness of the bonding layer is as shown in Table 1.

  Also in the case of the intermediate member for laser bonding having the third base material, sufficient bonding force was obtained, and water did not enter the smartphone even when the water immersion test was performed for 30 minutes at a water depth of 1 m. Moreover, although the smart phone was dropped from the height of 1.5 m, the panel did not peel from the casing. This is due to the fact that the front side bonding layer of the intermediate member for laser beam bonding in contact with the panel was softened or melted and adhered closely to the panel, and that the impact energy could be converted into thermal energy because the base material was flexible. It is.

Next, the smartphone was turned on in a dark room and observed for light leakage. No light leakage of the backlight from the gap between the panel and the case was observed, and a good smartphone screen was obtained.
This is because the dye of the bonding layer and the pigment of the base material selectively absorb and reflect visible light.

  Moreover, in Example 3, since the particle size of the white pigment of the rubber substrate is sufficiently smaller than the wavelength of the infrared laser light, it is not affected by Rayleigh scattering or Mie scattering. As a result, the laser beam reaches the surface of the housing without being reflected by titanium dioxide, the housing surface sufficiently generates heat, and the back side bonding layer of the intermediate member for laser light bonding contacting the housing is softened or melted. Adheres to the surface. Further, the design layer also generated heat sufficiently, and the front side bonding layer of the intermediate member for laser beam bonding was in close contact with the panel without any gap, so that sufficient bonding strength and waterproofness were obtained.

(Comparative Example 1)
38 μm transparent easy-adhesion PET (polyethylene terephthalate) film A 100 μm bonding layer with a separator was laminated on both sides of Cosmo Shine A4300 (PET substrate) manufactured by Toyobo Co., Ltd. to obtain a double-sided PSA sheet.

  Laser irradiation was performed in the same manner as in Example 1, and the same test was performed.

  About the double-sided pressure-sensitive adhesive sheet of the PET base material of Comparative Example 1, sufficient bonding strength was obtained, and water did not enter the smartphone even when a 30-minute immersion test was performed at a water depth of 1 m. However, when dropped from a height of 1.5 m, the panel and the casing slightly floated. This is due to the fact that the PET substrate was hard and could not absorb the impact sufficiently.

  Next, the smartphone was turned on in a dark room and observed for light leakage. Backlight light leaked from the gap between the panel and the case, and a good smartphone screen could not be obtained. This is because light leaked from the base material portion because the PET base material was transparent.

(Comparative Example 2)
Black pigment # 2650 manufactured by Mitsubishi Carbon Black Co., Ltd. was added to toluene in an amount of 10% by weight and dispersed by hand, followed by sufficient fine dispersion using a bead mill to obtain a black dispersion solution. Two-component curable solventless urethane A black dispersion and a curing agent were added to Pandex GW-1340 manufactured by DIC Corporation so that the black pigment concentration was 0.7% by weight, and the mixture was stirred so as to be sufficiently dispersed.

  The stirred solution was applied on the separator with an applicator so that the dry film was 200 μm, and heated with a dryer at 100 ° C. for 1 hour to obtain a black urethane substrate. A 100 μm joining layer with a separator was laminated on both sides of this urethane substrate in the same manner as in Example 1 to obtain a double-sided PSA sheet. And the laser beam was irradiated to the double-sided pressure-sensitive adhesive sheet while overlapping and clamping the casing and the double-sided pressure-sensitive adhesive sheet as in Example 1. However, since the surface of the urethane base material of the double-sided pressure-sensitive adhesive sheet was burnt and damaged, the bonding strength between the housing and the double-sided pressure-sensitive adhesive sheet was insufficient. This is due to the fact that the substrate surface absorbs all of the laser beam, the substrate surface is damaged, and the laser beam does not reach the housing, resulting in insufficient heat generation of the housing.

(Comparative Example 3)
A urethane substrate was prepared in the same manner as in Comparative Example 2. However, carbon black was made into 0.06 weight% with respect to urethane. In the same manner as in Example 1, a bonding layer was laminated on both surfaces of the urethane base material to obtain a double-sided pressure-sensitive adhesive sheet. About the double-sided adhesive sheet of a urethane base material, sufficient joining strength was obtained with respect to the housing | casing and the panel, and water did not permeate a smart phone even if the water immersion test was performed for 30 minutes at the water depth of 1 m. Moreover, although the smart phone was dropped from the height of 1.5 m, the panel did not peel from the casing.

  Next, when the smartphone was turned on in the dark room and observed for light leakage, backlight leakage from the gap between the panel and the case occurred, and a satisfactory smartphone screen could not be obtained. This is because the urethane base material does not absorb or reflect visible light sufficiently.

  (Measurement result of transmittance)

  Table 1 shows the light transmittance of each base material of Examples 1 to 3 and Comparative Examples 1 to 3 described above, the light transmittance of each bonding layer, and the backs of Examples 1 to 3 and Comparative Examples 1 to 3. It shows the presence or absence of light leakage and the joining status. The light transmittance was measured for each of wavelengths of 460 nm, 540 nm, 630 nm, and 940 nm. A spectrophotometer UV-3600 manufactured by Shimadzu Corporation was used for the measurement. In Comparative Example 2, the casing and the panel could not be joined, and the smartphone could not be manufactured, so the presence or absence of backlight light leakage could not be determined.

  In Examples 1 to 3, the light transmittance with a wavelength of 400 nm or more and less than 800 nm is 30% or less, and the base material, front side bonding layer and back side bonding layer with a wavelength of 800 nm or more and 1500 nm or less are 60% or more Therefore, it can be seen that there is no light leakage from the backlight and that the bonding condition is good.

  The above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the intermediate member for laser bonding and the bonding method according to the present invention are used, for example, in the case of manufacturing a cosmetic case, an exterior member for residential use or an electrical appliance, a mobile terminal, a mobile phone, a smartphone, or the like. be able to.

1 Joined product 10 Translucent member (first member)
20 Back side member (second member)
30 Design layer 40 Laser bonding intermediate member 41 Base material 42 Front side bonding layer (first bonding layer)
43 Back side bonding layer (second bonding layer)

Claims (5)

It is disposed between the design layer provided on the bonding surface side of the first member having a wavelength of 800 nm to 1500 nm and having a laser beam transparency, and the second member having a laser beam impermeability of the above wavelength, and In the laser beam bonding intermediate member for bonding the first member and the second member by irradiating laser light of a wavelength,
A first bonding layer disposed adjacent to the first member;
A second bonding layer disposed adjacent to the second member;
A substrate provided between the first bonding layer and the second bonding layer,
Transmittance of light having a wavelength of 400 nm or more and less than 800 nm irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding is 30% or less,
The laser beam having a transmittance of 60% or more for the laser beam having the wavelength irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding Intermediate member for joining. In the intermediate member for laser beam bonding according to claim 1,
An intermediate member for laser beam joining, comprising at least one of a urethane resin, a thermoplastic elastomer and rubber as a constituent component of the substrate. In the intermediate member for laser beam bonding according to claim 1 or 2,
An intermediate member for laser beam joining, comprising at least one of an organic pigment, an inorganic pigment, and a dye as a constituent component. In the intermediate member for laser beam joining according to any one of claims 1 to 3,
An intermediate member for laser beam bonding, wherein at least one of the first bonding layer and the second bonding layer has adhesiveness. For laser light bonding between a design layer provided on the bonding surface side of a first member having a laser beam transmittance of 800 nm or more and 1500 nm or less and a second member having a laser beam impermeability of the above wavelength In the joining method of arranging the intermediate member and joining the first member and the second member using the intermediate member for laser beam joining,
A first bonding layer disposed adjacent to the first member;
A second bonding layer disposed adjacent to the second member;
A substrate provided between the first bonding layer and the second bonding layer,
Transmittance of light having a wavelength of 400 nm or more and less than 800 nm irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser beam bonding is 30% or less,
Laser light bonding wherein the transmittance of laser light having a wavelength of 800 nm or more and 1500 nm or less irradiated to each of the first bonding layer, the base material, and the second bonding layer in the intermediate member for laser light bonding is 60% or more. Prepare intermediate members for
After the second bonding layer and the second member of the intermediate member for laser beam bonding are overlapped, the second member is heated by irradiating laser light of the wavelength from the first bonding layer side, After performing the first laser light irradiation for heating the second bonding layer by the heat of the two members,
After the design layer of the first member and the first bonding layer of the intermediate member for laser beam bonding are overlapped, the laser beam having the wavelength is irradiated toward the design layer, and the melting and decomposition temperature of the design layer A bonding method, wherein the design layer is heated to a predetermined temperature that does not exceed the temperature, and the second laser light irradiation is performed to heat the first bonding layer with the heat of the design layer.

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