JP5883966B2 - Joining method using laser light - Google Patents

Description

  The present invention relates to a joining method for joining various members using laser light.

  Conventionally, laser light has been used for joining various members. When joining using laser light, it is common to use one member as a laser light transmitting member and the other member as a laser light non-transmitting member. As shown in the figure, a resin containing toner or paint that absorbs laser light is interposed between one member and the other member, and the resin material is melted by absorbing the laser light, whereby the first A method of joining the second member is also known. According to this method, it becomes possible to join even if both members have laser beam transparency.

  Further, for example, in Patent Document 4, when an intermediate member for laser bonding is interposed between both members, a design layer is provided so that the design appears on the front side of the translucent member. It is disclosed that the design layer is heated in a temperature range in which the design layer is not melted and decomposed by irradiation with laser light, and the intermediate member is heated by the heat of the design layer to join both members.

JP 2003-181931 A JP 2004-1071 A JP 2005-238462 A JP 2011-156858 A

  By heating the design layer in a temperature range in which the design layer does not melt or decompose as in Patent Document 4, deterioration of the appearance of the product due to melting or decomposition of the design layer can be avoided. However, since the calorific value of the design layer cannot be increased, the intermediate member for laser bonding may become insufficiently heated in some cases. Particularly, in the intermediate member for laser bonding, the temperature of the portion opposite to the design layer is unlikely to rise, and as a result, the bonding strength between both members may not be sufficiently ensured.

  The present invention has been made in view of such points, and the object of the present invention is to join both members while avoiding melting and decomposition of the design layer when the design layer is interposed between the two members. It is to increase the strength sufficiently.

  In order to achieve the above object, in the present invention, an intermediate member for laser bonding is bonded to a member having no design layer using a laser beam, and then bonded to a member having a design layer.

1st invention is the joining method which joins the 1st member which has translucency, and the 2nd member using a laser beam,
Providing the first member with a laser light-impermeable design layer so that the design appears on the front side of the first member;
The intermediate member for laser joining having a multilayer structure for joining the first and second members and the second member are overlapped, and the surface on the first member side and the second member side in the intermediate member for laser joining A laser beam absorbent is contained in a bonding layer made of a thermoplastic hot melt material provided on at least one surface of the surface, and the first member is not overlaid on the laser bonding intermediate member, Then, after irradiating a laser beam and heating the said laser joining intermediate member and performing the 1st laser light irradiation which joins to the said 2nd member, after putting the said 1st member on the said laser joining intermediate member By performing second laser light irradiation for irradiating the design layer with a laser beam for heating the design layer until a predetermined temperature not exceeding the melting and decomposition temperature of the design layer is reached. By the heat of 該意 Takumi layer is characterized in that by heating the intermediate member for the laser junction and a step of bonding the first and second members.

  According to this configuration, since the second member has no design layer, even if the heat generation amount of the intermediate member for laser bonding is increased during the first laser light irradiation, the design layer is not affected. It becomes possible to sufficiently soften or melt the portion of the intermediate member opposite to the design layer to improve the degree of adhesion with the second member. This increases the bonding strength between the laser bonding intermediate member and the second member.

  Thereafter, the design layer of the first member is heated by the second laser light irradiation after the first member is overlaid on the laser joining intermediate member, so that the design layer side portion of the laser joining intermediate member is heated by the heat of the design layer. By heating, this makes it possible to join the intermediate member for laser joining and the first member without melting and decomposing the design layer.

  According to a second invention, in the first invention, the intermediate member for laser bonding is adhered to at least one of the first and second members.

  According to this configuration, since the intermediate member for laser bonding adheres to the first member or the second member, even if it is difficult to temporarily fix or bond and fix the intermediate member for laser bonding before the bonding, It becomes possible to use it and join reliably.

  According to the first invention, after joining the laser joining intermediate member to the second member, the design layer is heated at a predetermined temperature not exceeding the melting and decomposition temperature to join the laser joining intermediate member and the first member. Like to do. Thereby, when the design layer is interposed between the first and second members, the bonding strength of the first and second members can be sufficiently increased while avoiding melting and decomposition of the design layer.

  According to the second invention, since the laser joining intermediate member is adhered to at least one of the first and second members, the first member and the second member can be securely attached even when temporary fixing or the like is difficult. Can be joined.

It is sectional drawing of the joined goods joined using the joining method concerning Embodiment 1 of this invention. 2 is a cross-sectional view of an intermediate member for laser bonding according to Embodiment 1. FIG. It is sectional drawing which shows the case concerning Embodiment 1 and joining the intermediate member for laser joining, and a back side member by 1st laser beam irradiation. It is sectional drawing which shows the case concerning Embodiment 1 and joining the intermediate member for laser joining, and a translucent member by 2nd laser beam irradiation. FIG. 3 is a view corresponding to FIG. 1 according to a second embodiment of the present invention. FIG. 4 is a diagram corresponding to FIG. 3 according to the second embodiment. FIG. 5 is a diagram corresponding to FIG. 4 according to the second embodiment. It is a figure which shows the preparation methods of the intermediate member for laser joining concerning an Example. It is a figure explaining the process of the 1st laser beam irradiation concerning an Example. It is a figure explaining the process of the 2nd laser beam irradiation concerning an Example.

  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.

(Embodiment 1)
FIG. 1 shows a bonded product 1 bonded by a bonding method using laser light according to Embodiment 1 of the present invention. The joined product 1 is used as, for example, a cosmetic case, a housing or an exterior member for electrical appliances, and the like. The translucent member (first member) 10 constituting the front side of the exterior member and the back side are used. The back side member (2nd member) 20 which comprises is overlapped, and the design layer 30 which comprises a part of translucent member 10 is provided in the back surface of the translucent member 10. FIG. The translucent member 10 and the back side member 20 are joined by a laser joining intermediate member 40.

  The back-side member 20 is a plate-like member made of a material having a laser beam permeability that transmits laser light, or a plate-like member made of a material having a laser beam impermeability that does not transmit laser light. . Here, the laser beam transmissivity is a property of transmitting laser light, refers to a property of transmitting 15% or more of laser light as a heating source, and includes one that transmits all of the laser light. Examples of the material having such properties include materials such as plastic, glass, and a thin metal oxide film. On the other hand, laser light non-transmission means laser light absorption that absorbs laser light, and refers to the property of absorbing the remainder even if the laser light as a heating source is partially transmitted and / or reflected, Includes those that absorb all of the laser light. As materials having such properties, there are, for example, materials obtained by mixing pigments and dyes with resins and rubbers in addition to metals and ceramics. As the laser light non-light-transmitting property, for example, the transmittance of laser light having a wavelength of 940 nm is preferably less than 15%. In the first embodiment, the back side member 20 is made of a metal material.

  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 laser light to pass through. Laser light transmission means that the laser beam as a heating source is transmitted with almost no reflection or absorption, or the remaining laser beam is transmitted without melting even if the laser beam is partially transmitted and / or reflected. This includes the properties that can be transmitted, including those that transmit all of the laser light.

  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), 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), ethylene tetrafluoroethylene copolymer, liquid crystal polymer, polybutylene terephthalate, polyether ether ketone, polyether ketone, polyether ketone ketone, polyethylene Ren naphthalene, polyethylene terephthalate, polyimide, polyacetal, polyamideimide, polyphenylene ether, polyphenylene oxide, polycarbonate, polyphenylene sulfide, polysulfone, polythioether sulfone, polytetrafluoroethylene, polyether sulfones and polyether imide.

  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, chlorinated modified olefin resins (CPP, CPE), silane-modified olefin resins, and 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.

  The translucent member 10 may be a thermosetting rubber. Specifically, natural rubber, isoprene rubber, ethylene propylene diene rubber, ethylene propylene rubber, styrene butadiene rubber, butadiene rubber, chlorosulfonated polyethylene rubber , Isoprene rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, silicon rubber 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. As the laser beam transparency, for example, the transmittance of a laser beam having a wavelength of 940 nm is preferably 20% or more, and more preferably 50% or more. 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 an exterior member, it is about several mm. Further, the back side member 20 may be made of a laser light transmissive member.

  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 and is visible from the front side of the translucent member 10.

  For ink curable compounds, for example, acrylate, urethane acrylate, epoxy acrylate, carboxyl group-modified epoxy acrylate, polyester acrylate, unsaturated polyester resin, copolymer acrylate, polyacryl acrylate, alicyclic epoxy resin, glycidyl ether epoxy Examples thereof include resins, vinyl ether compounds, oxetane compounds and the like.

  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 non-transparency, and may be a natural dye such as red or safflower, a synthetic dye such as a reaction, sulfurization or naphthol, or a fluorescent dye. In addition, the pigment is not particularly limited as long as it has a laser beam impermeability, and examples thereof include inorganic pigments such as carbon black and composite oxide pigments, phthalocyanine pigments, azo pigments, lake pigments, and polycyclic pigments. Examples thereof include organic pigments such as pigments, and various pigments having non-transparency corresponding to the wavelength of laser light 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 character, a figure, a symbol, a picture, a gradation pattern, the painting 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 100 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, it is preferable that the transmittance of the laser beam having a wavelength of 940 nm is less than 15%.

  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 laser bonding intermediate member 40 includes a base material 41 made of a film, and a front side bonding layer 42 and a back side bonding layer 43 provided on both surfaces of the base material 41, respectively. The base material 41 is made of, for example, a resin material such as polyethylene terephthalate. In the first embodiment, the thickness is 38 μm, but the present invention is not limited to this. The base material 41 does not contain a laser light absorber.

  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 materials of the front side bonding layer 42 and the back side bonding layer 43 may be the same or different, and the thickness is set to 100 μm, but the thickness is not limited to this. 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 laser light. Among the high-molecular substances (tackifiers and elastomers) that exhibit rubber elasticity near normal temperature, Those having plasticity are preferred. That is, as a material of the front side bonding layer 42 of the intermediate member 40 for laser bonding, the above-described tackifier, thermoplastic elastomer, cross-linked rubber, and the like can be used. System, acrylic system, urethane system, silicon system and the like. 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 are also commonly used as a base for rubber-based tackifiers, and are not particularly limited, but can be used as tackifiers by blending tackifiers, oils, liquid oligomers, crosslinking agents, and the like.

  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 rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), unsaturated fatty acid modified rosins and unsaturated fatty acid modified rosin esters Rosin alcohols such as unmodified rosin, modified rosin and various rosin derivatives Oxazines (especially, 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. Other heat stabilizers, antioxidants, UV stabilizers, conductive agents, nucleating agents, mold release agents, flame retardants, antistatic agents, processing preparations, colored and functional pigments or dyes, crosslinking agents, plastics It is preferable to use at least one selected from the group consisting of an agent and a vulcanizing agent.

  Examples of the crosslinked rubber include natural rubber, isoprene rubber, ethylene propylene diene rubber, ethylene propylene rubber, styrene butadiene rubber, butadiene rubber, chlorosulfonated polyethylene rubber, isoprene rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber, urethane. Examples thereof include rubber, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, and silicon rubber. These crosslinked rubbers may contain various additives as required. For example, aromatic mercaptan-based, aromatic disulfide-based, aromatic mercaptan zinc-based peptizer, organic acid-based, nitroso-compound-based, sulfenamide-based scorch inhibitor, paraffin-based, aromatic-based, naphthenic-based, Liquid rubber plasticizer, rosin derivative, terpene natural resin tackifier, coumarone (indene) resin, petroleum resin, alkylphenol resin, xylene / formaldehyde resin and other synthetic resin tackifiers, Halogen-based, metal hydrate-based, silicon-based, phosphorus-based flame retardants, antioxidants, heat stabilizers, light stabilizers, UV absorbers, lubricants, pigments, cross-linking agents, cross-linking aids, vulcanization return inhibitors, Common rubber plastic compounding chemicals such as a silane coupling agent and a titanate coupling agent can be mentioned.

  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 cross-linked rubber is used as the material of the front side bonding layer 42 of the laser bonding intermediate member 40, the degree of cross-linking is lower in order to avoid a decrease in weldability due to laser light. Is preferred.

  More specifically, the hot melt material constituting the front side bonding layer 42 of the laser bonding intermediate member 40 is preferably, for example, an acrylic block polymer having elasticity at room temperature. The hot melt material may be, for example, SIS (styrene-isoprene-styrene), SBS (styrene-butadiene-styrene), SEBS (styrene-hydrogenated butadiene-styrene), or the like.

  A heat conductive filler is mixed in the front side bonding layer 42 of the intermediate member 40 for laser bonding. Examples of the thermally conductive filler include metal oxides such as aluminum oxide, silicon oxide, and magnesium oxide, and inorganic nitrides such as silicon nitride, boron nitride, aluminum nitride, titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride. There is.

  Other heat conductive fillers include potassium titanate, aluminum borate, magnesium sulfate, calcium carbonate and their whiskers, glass fibers, carbon fibers, metal fibers, aramid fibers, asbestos, silicon carbide, ceramics, barium sulfate, calcium sulfate, Kaolin, clay, silica, pyrophyllite, bentonite, sericite, zeolite, montmorillonite, mica, mica, nepheline cinteite, talc, atarbalsite, wollastonite, PMF, ferrite, calcium silicate, magnesium carbonate, dolomite, Examples thereof include zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloon, quartz, and quartz glass. The filler used may be hollow. These fillers can be used in combination of two or more, and can be used after pretreatment with a coupling agent such as silane or titanium if necessary.

  Further, a heat conductive film, cloth, aluminum foil, copper foil or the like may be used as a part of the intermediate member 40 for laser bonding. The thickness of the aluminum foil is preferably about 50 μm, for example, and the thickness of the copper foil is preferably about 30 μm, for example. Moreover, it is not restricted to aluminum foil and copper foil, You may use various metal films and sheets as a part of the intermediate member 40 for laser joining.

  Furthermore, the back side bonding layer 43 of the intermediate member 40 for laser bonding contains a laser light absorber that absorbs laser light. In the first embodiment, the laser light absorber is contained only in the back side bonding layer 43.

  Examples of laser light absorbers include black absorbers, carbon black, lamp black, bone black, graphite or metal oxide magnetite, titanium black, chromium oxide, etc. as inorganic pigments, and azo pigments as organic pigments. And polycyclic pigments.

  Absorbers that absorb wavelengths in the near-infrared region can also be used as laser light absorbers, for example, mianine dyes, thionyl nickel complexes, bis- [mis 1,2 toluyl] ethylene-1,2, dithio. Metal complexes such as rate nickel, bis- [1chloro-3,4-dithiolate] nickel / tetrabutylammonium can be used suitably, and squarylium dyes such as diethylaminonaphthol squarylium and dimethylaminonaphthol squarylium having a maximum absorption wavelength at 830 nm Can also be used. Furthermore, polymethine dyes, (di) imonium dyes, phthalocyanine dyes, triallylmethane dyes, naphthoquinone dyes, and the like can be suitably used.

  The laser absorbent is not limited to these, and any material that absorbs laser light and generates heat can be used by being dissolved or dispersed.

  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.

  By including the tackifier, the surface on the back side member 20 side and the surface on the translucent member 10 side of the intermediate member 40 for laser bonding have adhesiveness. 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.

  Examples of the tackifier include those described above.

  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 adhesive strength after laser light irradiation can also be improved.

  Then, as shown in FIG. 3, the laser bonding intermediate member 40 is stacked 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, the laser beam L is applied to the laser bonding intermediate member 40 from the front bonding layer 42 side of the laser bonding intermediate member 40. 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, and the type of the laser beam L is not limited. 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 and the base material 41 of the intermediate member 40 for laser bonding do not contain a laser light absorber, most of the laser light L is transmitted through the front side bonding layer 42 and the base material 41 and the back side bonding layer 43. To be absorbed. The back side bonding layer 43 that has absorbed the laser light L generates heat. Moreover, when there exists the laser beam L which passed the back side joining layer 43 among the laser beams L, if the back side member 20 contains the laser beam absorber, it will be absorbed by the back side member 20 and the back side member 20 will generate | occur | produce heat.

  As a result, the back side bonding layer 43 is melted or softened, deforms and adheres along the surface of the back side member 20, and the laser bonding intermediate member 40 is bonded to the back side 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.

  Thereafter, as shown in FIG. 4, the translucent member 10 is overlaid on the front side bonding layer 42 of the intermediate member 40 for laser bonding. 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.

  The translucent member 10 and the back side member 20 may be clamped in the thickness direction. By clamping, the translucent member 10 and the back side member 20 are expanded and translucent due to heat generation when the laser light L is irradiated. Since generation | occurrence | production of the bubble between the member 10 and the back side member 20 can be suppressed, the reliability of joining can be improved more.

  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.

  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. Since the thermally conductive filler is mixed in the laser bonding intermediate member 40, the heat of the design layer 30 is easily transmitted to the entire laser bonding intermediate member 40. 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 pass through the design layer 30. The slight laser light L that has passed through the design layer 30 reaches the laser joining intermediate member 40. Since the laser light absorber is mixed in the laser bonding intermediate member 40, the laser light L transmitted through the design layer 30 is absorbed by the laser bonding intermediate member 40. Also by this, the laser bonding intermediate member 40 is heated to a slight extent, so that the laser beam L can be used effectively.

  As described above, according to the bonding method according to the first embodiment, since the laser light L at the time of the second laser light irradiation can be a low output of about several W, 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 welding the translucent member 10 and the back side member 20 by irradiation of the laser beam L, it receives the 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 or an elastomer, 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.

  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 for a long period of time.

  As described above, according to the joining method according to the first embodiment, after the laser joining intermediate member 40 is joined to the back member 20 by the first laser light irradiation, the light transmitting member 10 is joined to the laser joining intermediate member 40. The second laser beam irradiation is performed on the laser beam, and the design layer 30 is heated to a predetermined temperature that does not exceed the temperature at which the design layer 30 melts and decomposes to bond the laser joining intermediate member 40 and the translucent member 10 together. I am doing so. 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.

  In addition, since the laser beam absorbent is included in the bonding layer 43 on the back side member 20 side in the laser bonding intermediate member 40, even if the back side member 20 transmits or reflects laser light, The back side member 20 can be joined.

  In addition, since the laser joining intermediate member 40 is adhered to the light transmitting member 10 and the back side member 20 before the laser light L is irradiated, the light transmitting member 10 and the back side member 20 can be attached even when temporary fixing or the like is difficult. It can be reliably joined.

  Further, since the laser joining intermediate member 40 is a hot melt material, sufficient adhesive strength can be obtained.

  Further, since the heat conductive filler is mixed in the laser bonding intermediate member 40, the heat of the design layer 30 is easily transmitted to the entire laser bonding intermediate member 40, and the laser bonding intermediate member 40 is surely melted and bonded. Can be reliably performed.

  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 by softening the intermediate member 40 for laser bonding, the intermediate member 40 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 bubbles in the joint portion by softening the intermediate member 40 so that the air tightness and the water tightness are improved. In particular, in an adhesive tape having a narrow width, the effect of improving airtightness and watertightness is remarkable.

  In addition, the front side bonding layer 42 of the laser bonding intermediate member 40 may contain a laser light absorber, and the back side bonding layer 43 may not contain a laser light absorber. Also in this case, the back side bonding layer 43 can be melted by irradiating the laser beam L to the laser bonding intermediate member 40. Moreover, you may make the front side joining layer 42 and the back side joining layer 43 contain a laser beam absorber.

  Moreover, in the said Embodiment 1, although the intermediate member 40 for laser joining is made into the 3 layer structure, you may make it not only this but a 2 layer structure, for example.

(Embodiment 2)
5 to 7 relate to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in that the laser bonding intermediate member 40 has a single-layer structure, and the translucent member 10 and the back member 20 are the same as those in the first embodiment.

  The intermediate member 40 for laser bonding according to the second embodiment is made of the same material as the material for the back side bonding layer 43 of the intermediate member 40 for laser bonding according to the first embodiment.

  Next, a manufacturing procedure according to the second embodiment will be described.

  First, similarly to the first embodiment, the laser bonding intermediate member 40 is overlaid on the back side member 20 so that the back side of the laser bonding intermediate member 40 overlaps the front side of the back side member 20 (see FIG. 6). At this time, when the laser bonding intermediate member 40 has adhesiveness, the laser bonding intermediate member 40 is temporarily fixed to the back side member 20, and the displacement of the laser bonding intermediate member 40 is suppressed. Is done.

  Then, the laser beam L is irradiated to the laser bonding intermediate member 40 from the front side of the laser bonding intermediate member 40. This is the first laser light irradiation.

  Since the laser joining intermediate member 40 contains a laser absorbent, the laser light is absorbed by the laser joining intermediate member 40. The laser joining intermediate member 40 that has absorbed the laser light L generates heat.

  As a result, the intermediate member 40 for laser bonding is melted or softened, deformed and adhered along the surface of the back side member 20, and the intermediate member 40 for laser bonding is bonded to the back side member 20. In FIG. 6, a part indicated by a white circle is a part 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 intermediate member 40 for laser joining can be reliably melted or softened.

  Thereafter, as shown in FIG. 7, the translucent member 10 is overlaid on the front side of the laser joining intermediate member 40. At this time, when the laser joining intermediate member 40 has adhesiveness, it is possible to suppress the positional deviation between them without clamping the light transmitting member 10 and the back member 20.

  Then, the laser beam L is irradiated from the translucent member 10 side toward the design layer 30. This is the second laser light irradiation.

  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. In FIG. 7, a part indicated by a white circle is a part mainly heated by the laser light L.

  The heat of the design layer 30 is transmitted to the adjacent intermediate member 40 for laser bonding. Since the thermally conductive filler is mixed in the laser bonding intermediate member 40, the heat of the design layer 30 is easily transmitted to the entire laser bonding intermediate member 40. The laser joining intermediate member 40 is heated to a melting temperature to melt or soften. Thereby, it closely_contact | adheres to the design layer 30 of the translucent member 10, and joins.

  As described above, according to the joining method according to the second embodiment, as in the first embodiment, the light transmitting member 10 can be prevented from being damaged (burned or deformed) by heat.

  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.

  As described above, according to the bonding method according to the second embodiment, as in the first embodiment, the bonding strength between the translucent member 10 and the back member 20 is increased while avoiding melting and decomposition of the design layer 30. It can be raised enough.

  Moreover, the joining method concerning this invention is applicable when manufacturing various joining goods besides the case for cosmetics, the housing for housing, or the exterior member for electrical products.

Examples of the present invention will be described below, but the present invention is not limited to these examples, and there are various examples.
Example 1
First member The first member 10 was a plate made of transparent polycarbonate having a thickness of 2 mm. The design layer 30 was obtained by printing UV screen ink black (manufactured by Jujo Chemical Co., Ltd .: Reicure GA4100) on the back surface of a polycarbonate plate by screen printing, and then irradiating it with ultraviolet rays and curing it. The thickness of the design layer 30 is 10 μm, and the formation range of the design layer 30 is 60 mm × 60 mm. The transmittance of the laser beam in the portion having the design layer 30 in the translucent member 10 was 4%.

Second member The first member 20 was a plate material made of stainless steel (SUS304) having a thickness of 2 mm.

Preparation of intermediate member 50 parts by weight of an acrylic elastomer (LA2250 manufactured by Kuraray Co., Ltd.) and 50 parts by weight of a tackifier (SE-A-115 manufactured by Arakawa Chemical Industries, Ltd.) were added to 100 parts by weight of toluene and stirred. It melt | dissolved and the adhesive composition solution was produced.

  Carbon black (PRINTEK 35, manufactured by Evonik Degussa Japan Co., Ltd.) was added to the solid content of the pressure-sensitive adhesive composition and dispersed with a roll mill to obtain a laser-absorbing pressure-sensitive adhesive composition solution.

  The above solution was applied onto a release film-treated PET film (SKB-2 manufactured by Fujiko Co., Ltd.) with an applicator so that the film thickness after drying was 100 μm. The thickness of the PET film is 38 μm.

  The release-treated film after application of the solution was placed in an oven having a chamber temperature of 70 ° C. for 10 minutes to dry the solution to obtain a single-layer laser joining intermediate member 40 on the release-treated film. (See FIG. 8 (a)).

First laser light irradiation The intermediate member 40 for laser bonding on the release-treated film was cut out using a cutter so as to form a square frame shape of 50 mm × 50 mm (see FIG. 8B). The width of the frame is 1 mm.

  The intermediate member 40 for laser bonding molded into a frame shape was attached to the first member 20 while being attached to the release-treated film. A glass plate having a thickness of 10 mm was placed thereon, and a clamp pressure of 5 kg was applied.

  Then, the laser beam was irradiated from the front side of the glass plate (first laser beam irradiation). The focus of the laser beam was adjusted to the laser joining intermediate member 40. The wavelength of the laser light is 940 nm, the output is 10 W, and the scanning speed is 500 mm / min.

Second Laser Light Irradiation After the first laser light irradiation, the glass plate was removed, and the release-treated film was peeled off from the intermediate member 40 for laser bonding. Then, the 2nd member 20 was set | placed so that the design layer 30 might contact the intermediate member 40 for laser joining, and the 2nd member 20 was affixed on the intermediate member 40 for laser joining.

  Thereafter, the glass plate was placed on the front side of the second member 20 in the same manner as in the first laser light irradiation, and a clamping pressure was applied.

  Next, laser light was irradiated from the front side of the glass plate (second laser light irradiation). The focus of the laser beam was adjusted to the laser joining intermediate member 40. The wavelength of the laser light is 940 nm, the output is 3 W, and the scanning speed is 500 mm / min.

  At this time, the design layer 30 was not discolored or damaged.

(Example 2)
In the second embodiment, the first member 10 and the second member are the same as those in the first embodiment.

  Moreover, when producing the intermediate member 40 for laser bonding, the pressure-sensitive adhesive composition solution containing no carbon black is dried on a PET film (Lumoror S10 manufactured by Toray Industries, Inc.) having a thickness of 38 μm that has not been subjected to mold release treatment. It applied with the applicator so that the film thickness after that might be set to 100 micrometers. Then, it dried in oven similarly to Example 1, and obtained the 1st member 20 side joining layer (front side joining layer). The PET film not subjected to the release treatment corresponds to the base material of the present invention.

  A PET film with a release treatment of 38 μm in thickness is pasted on the surface of the front side bonding layer, and prepared in Example 1 on the surface opposite to the front side bonding layer in the base material (PET film which has not been released). The obtained laser-absorbing pressure-sensitive adhesive composition solution was applied with an applicator so that the film thickness after drying was 100 μm, dried in an oven in the same manner as in Example 1, and the second member 20 side bonding layer (back side bonding layer) )

  The laser bonding intermediate member 40 having the three-layer structure (front side bonding layer, base material, and back side bonding layer) obtained as described above is formed into a rectangular frame shape in the same manner as in Example 1 and attached to the release-treated film. It stuck on the 2nd member 20 as it was. And 1st laser beam irradiation was performed similarly to the 1st laser beam irradiation of Example 1. FIG.

  Then, after arrange | positioning the 1st member 10 so that the design layer 30 of the 1st member 10 might overlap with the front side joining layer of the intermediate member 40 for laser joining, 2nd laser beam irradiation was performed similarly to Example 1. FIG.

(Comparative example)
The first member 10, the second member 20, and the laser joining intermediate member 40 of Example 2 were prepared and joined without performing the first laser light irradiation. That is, after the first member 10, the laser bonding intermediate member 40 and the second member 20 were sequentially stacked, a glass plate was stacked on the first member 10 and a laser beam was applied after applying a clamping pressure.

  The laser beam irradiated in the comparative example prevents the design layer 30 from being discolored or damaged, has a wavelength of 940 nm, an output of 3 W, and a scanning speed of 500 mm / min.

Bondability test Fifty bonded articles 1 of Example 1, Example 2 and Comparative Example were prepared.

  These were submerged in water at a depth of 2 m for 24 hours to compare waterproofness.

  As a result, in Examples 1 and 2, no water intrusion was observed inside the laser joining intermediate member 40 (inside the frame) in all 50 joined products 1. That is, it is possible to stably obtain a strong bonding force that can sufficiently withstand a water pressure of about 2 m.

  On the other hand, in the comparative example, since the invasion of water was recognized inside the intermediate member 40 for laser bonding in the two bonded articles 1, it can be seen that an individual having insufficient bonding force is generated.

  As described above, the joining method using the laser beam according to the present invention can be used, for example, to manufacture a cosmetic case, a housing or an electrical product exterior member, and the like.

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 43 Back Side Bonding Layer L Laser Light

Claims (2)

In the joining method of joining the first member having translucency and the second member using laser light,
Providing the first member with a laser light-impermeable design layer so that the design appears on the front side of the first member;
The intermediate member for laser joining having a multilayer structure for joining the first and second members and the second member are overlapped, and the surface on the first member side and the second member side in the intermediate member for laser joining A laser-absorbing agent is contained in a bonding layer made of a thermoplastic hot melt material provided on at least one of the surfaces, and the first member is not placed on the intermediate member for laser bonding. After the first laser beam irradiation is performed by irradiating the laser beam to heat the laser bonding intermediate member and bonding it to the second member, the first member is stacked on the laser bonding intermediate member, and then the design is performed. Performing a second laser beam irradiation to irradiate a laser beam for heating the design layer until reaching a predetermined temperature not exceeding the melting and decomposition temperature of the design layer toward the layer, Bonding method using a laser beam, characterized in that the heat of the Takumi layer by heating the intermediate member for the laser junction and a step of bonding the first and second members. In the joining method using the laser beam according to claim 1,
A bonding method using laser light, wherein the laser bonding intermediate member is adhered to at least one of the first and second members.

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