JP6657112B2 - Application method of adhesive and bonded product - Google Patents

Description

  The present invention relates to a coating method for applying a pressure-sensitive adhesive to a member and a joined product formed by bonding with the pressure-sensitive adhesive.

  For example, in the case of producing a pressure-sensitive adhesive containing a styrene-based thermoplastic elastomer, the pressure-sensitive adhesive can be obtained by mixing a tackifier (tackifier) or a liquid rubber for giving flexibility to the styrene-based thermoplastic elastomer. . The method of mixing the raw materials and the method of molding are roughly divided into the following two methods.

  One of them is a solvent dissolving method in which a raw material is dissolved in a hydrocarbon solvent such as toluene, hexane, or xylene to obtain a sheet-shaped pressure-sensitive adhesive by thin coating, and another is a solvent dissolving method in which This is a twin-screw extrusion method in which a kneading is performed by applying a shearing force while heating with a screw extruder, extruding and die-coating to form a sheet-shaped adhesive or a pellet-shaped adhesive.

  Regardless of the solvent dissolution method or the twin-screw extrusion method, the obtained sheet-shaped pressure-sensitive adhesive may be once stuck on a support before being stuck to a member (before use), or separated. In general, the paper is sandwiched between a paper pattern and a release-treated PET (polyethylene terephthalate) film and stored.

  In addition, as a form when using the pressure-sensitive adhesive, there is a hot melt method in which a pellet-shaped pressure-sensitive adhesive molded by a twin-screw extrusion method is put into a syringe, heated, and discharged, in addition to the above-described sheet shape. However, the hot-melt method of a styrene-based pressure-sensitive adhesive is currently limited in its use range to those requiring only the bonding function such as disposable diapers, sanitary products, and packing materials.

  Further, as an example of the hot melt method, there is known a method in which an adhesive is heated and melted in a cylinder, discharged from a dispenser nozzle, and applied to a member, as disclosed in Patent Document 1, for example.

JP 2014-91231 A

  By the way, an adhesive containing a styrene-based thermoplastic elastomer or the like is sometimes used, for example, when joining a housing of an electronic device such as a smartphone to a display panel. Especially in the case of electronic equipment, the styrene-based pressure-sensitive adhesive is not formed by hot-melt using pellets, but is coated by a solvent dissolution method to form a sheet, and this sheet is cut and punched and processed into a desired shape for use. Have been. The reason is that, as in an example of a hot melt method disclosed in Patent Document 1, when a styrene-based pressure-sensitive adhesive is heated and melted in a cylinder, discharged from a dispenser nozzle and applied to a member, Until the styrene-based adhesive is discharged, the cylinder is held in a state where the styrene-based adhesive is heated to a temperature higher than the melting temperature for a long time. The polymer resin that constitutes the styrene-based pressure-sensitive adhesive is gelled due to the effect of clogging, it becomes clogged when trying to discharge from a syringe and it can not be discharged, and the mechanical properties such as tensile strength and elongation decrease significantly. This is because the desired performance as an adhesive cannot be obtained. This problem can also occur in the case of a pressure-sensitive adhesive other than the styrene-based pressure-sensitive adhesive when the pressure-sensitive adhesive composition contains a heat-sensitive adhesive.

  On the other hand, in recent years, in electronic devices having a display panel such as a mobile phone, a smartphone, and a wearable device, a sheet-shaped adhesive is cut into thin pieces so that the width of the adhesive to be joined to a housing becomes narrower. Therefore, there is a demand for a so-called narrow frame in which the display area of the display panel is enlarged as much as possible without increasing the outer shape of the electronic device. However, assuming a case where a sheet-shaped adhesive is mechanically punched to be cut into small pieces, the minimum width of the adhesive that can be stably punched is limited, and it is difficult to further narrow the frame. Further, in the case of a sheet-shaped adhesive, it is difficult to adhere the adhesive in a three-dimensional shape such as a curved surface of the joining surface of the member, so that the joining surface is required to be flat, The application range for the joint surface is narrow.

  Further, the sheet-shaped pressure-sensitive adhesive obtained by the solvent dissolution method has a problem of work environment and workability since an organic solvent is used as a solvent. Furthermore, since the sheet-shaped adhesive is punched into a usable shape, the remaining punched part, for example, 90% or more of the adhesive must be discarded, which causes a problem that the cost of the product is increased. .

  The present invention has been made in view of such a point, and an object of the present invention is to make it difficult for a resin component of an adhesive to receive heat history and to secure expected performance, The application width can be reduced, and even if the shape of the joining surface is complicated, the adhesive can be applied so that the range of the object to be joined by the adhesive is expanded, and the working environment and workability are improved. In addition, there is a need to reduce the amount of pressure-sensitive adhesive to be discarded to reduce costs.

  In order to achieve the above object, in the present invention, a long and thin processed pressure-sensitive adhesive is subjected to anti-adhesion treatment, and the anti-adhesion-treated pressure-sensitive adhesive is heated and melted for a short time, and is applied to a joint surface. did.

The first invention is
In a method for applying an adhesive which applies an adhesive which is softened or melted by heating to a predetermined temperature or more to a joint surface of a member,
A molding step of elongating the pressure-sensitive adhesive,
An anti-adhesion treatment step of performing an anti-adhesion treatment on the surface of the elongated pressure-sensitive adhesive molded in the molding step,
A storage step of storing the adhesive subjected to the anti-adhesion treatment in the anti-adhesion processing step until use,
The pressure-sensitive adhesive stored in the storage step is supplied to a heating member having a discharge hole and heated inside or near the discharge hole, and is softened or melted and discharged from the discharge hole, thereby joining the members. And a coating step of coating the surface.

  According to this configuration, the elongated adhesive formed in the molding step is subjected to the anti-adhesion treatment, so that the adhesives do not stick to each other in the storage step, and the storability is improved. Then, by feeding the stored pressure-sensitive adhesive to the heating member, the pressure-sensitive adhesive is heated or softened or melted inside or near the ejection hole. By heating inside or in the vicinity of the ejection hole in this way, the time during which the adhesive is in the heated state is shorter than in the case where the adhesive is heated in a state where the adhesive is accommodated in the syringe as in the conventional example. Therefore, the pressure-sensitive adhesive is less susceptible to heat history, so that the gelation of the resin component is suppressed, and a decrease in bonding strength after bonding is suppressed.

  In addition, by forming the pressure-sensitive adhesive elongated in advance in the molding step, it is possible to sufficiently narrow the application width of the pressure-sensitive adhesive, for example, when applied to an electronic device having a display panel, even more. The frame can be narrowed. Further, by applying the softened or melted pressure-sensitive adhesive to the joining surface, even if the joining surface has a complicated shape, it can be easily applied so as to follow the shape. Further, since the use of an organic solvent as in the solvent dissolving method is unnecessary, the working environment and workability are improved. In addition, when applying the adhesive, only the necessary amount of the stored adhesive needs to be fed to the heating member, so that the amount of the adhesive to be discarded is smaller than when a conventional sheet-shaped adhesive is punched. Is significantly reduced.

In a second aspect, in the first aspect,
In the storage step, the elongated adhesive is wound around a winding member.

  According to this configuration, the elongated adhesive is stored neatly without being entangled, so that it can be smoothly fed to the heating member during use.

A third invention is the first or second invention, wherein
In the molding step, the pressure-sensitive adhesive is molded so that the diameter is 0.5 mm or more and 5.0 mm or less,
In the application step, the pressure-sensitive adhesive is heated to a temperature of 140 ° C. or more and 300 ° C. or less, and the heating and holding time of the pressure-sensitive adhesive is set to 1 second or more and 10 seconds or less.

  According to this configuration, by setting the diameter of the pressure-sensitive adhesive to be 0.5 mm or more and 5.0 mm or less, for example, a bonding area when a housing of an electronic device or the like and a display panel are bonded is sufficiently ensured and high bonding is achieved. Strength is obtained. Then, the adhesive is heated to a temperature of 140 ° C. or more and 300 ° C. or less, and the temperature is maintained for 1 second or more, so that the adhesive is reliably softened or melted. On the other hand, since the heating holding time is as short as 10 seconds or less, it is difficult for heat history to accumulate in the resin component of the adhesive.

According to a fourth aspect, in any one of the first to third aspects,
The width of the adhesive applied to the joint surface of the member in the application step is set to 0.2 mm or more and 1.0 mm or less, and the height of the adhesive based on the joint surface is set to 50 μm or more and 500 μm or less. It is characterized by.

  According to this configuration, for example, a frame can be narrowed when a housing of an electronic device or the like and a display panel are joined. By setting the height of the pressure-sensitive adhesive to 50 μm or more, the ability of the pressure-sensitive adhesive to follow the bonding surface is ensured.

According to a fifth aspect, in any one of the first to fourth aspects,
At least a thermoplastic elastomer or unvulcanized rubber and a tackifier are mixed to obtain a pressure-sensitive adhesive.

  According to this configuration, a strong adhesive force is obtained, and the adhesive is excellent in tensile strength.

According to a sixth aspect, in any one of the first to fifth aspects,
In the above-mentioned anti-adhesion treatment step, an anti-adhesion agent obtained by mixing any one or more selected from the group consisting of metal soap, flaky clay mineral, and inorganic fine particles is attached to the adhesive.

  According to this configuration, the adhesive can be easily and reliably provided with anti-adhesion properties.

  A seventh invention is characterized in that in the applying step, the adhesive is fed to the heating member by a conveying screw.

  In an eighth aspect of the present invention, in the application step, an adhesive is disposed between the first endless member and the second endless member that are circulated and driven to pass through a predetermined path, and the first endless member and The adhesive is fed to the heating member by circulating the second endless member.

According to this configuration, since the adhesive is fed while being sandwiched between the surfaces of the first endless member and the second endless member, the adhesive is fed to the heating member without buckling .

  According to the first invention, the pressure-sensitive adhesive is formed into an elongated shape, subjected to an anti-adhesion treatment and then stored, and the stored pressure-sensitive adhesive is fed to a heating member having a discharge hole to discharge the inside of the discharge hole or It can be heated in the vicinity and discharged from the discharge hole to be applied to the joint surface of the member. As a result, the desired performance can be ensured by making the resin component of the adhesive less likely to receive heat history, and the width of application of the adhesive can be reduced, and even if the bonding surface has a complicated shape, By applying the agent, the range of the object to be joined by the adhesive can be expanded, the working environment and workability can be improved, and the amount of the adhesive to be discarded can be reduced to reduce the cost.

  According to the second aspect of the present invention, the elongate adhesive is wound around the winding member and stored, so that the elongate adhesive can be stored neatly without tangling, and can be smoothly fed to the heating member during use. can do.

  According to the third invention, the pressure-sensitive adhesive is molded so that the diameter is 0.5 mm or more and 5.0 mm or less, and the pressure-sensitive adhesive is heated until the temperature becomes 140 ° C. or more and 300 ° C. or less, and the heat holding time is reduced. Since the time is from 1 second to 10 seconds, the bonding strength by the adhesive can be sufficiently ensured.

  According to the fourth invention, the width of the adhesive applied to the joint surface of the member is set to 0.2 mm or more and 1.0 or less, and the height of the adhesive is set to 50 μm or more and 500 μm or less. Sufficient bonding strength can be obtained while narrowing the frame.

  According to the fifth invention, since at least the thermoplastic elastomer or unvulcanized rubber and the tackifier are mixed to obtain the pressure-sensitive adhesive, a strong pressure-sensitive adhesive force is obtained, and the pressure-sensitive adhesive having excellent tensile strength is obtained. Agent.

  According to the sixth invention, an anti-adhesive agent obtained by mixing any one or more selected from the group consisting of metal soap, flaky clay mineral, and inorganic fine particles is attached to the adhesive. The agent can be easily and reliably provided with anti-adhesion properties.

  According to the seventh and eighth aspects, the adhesive can be stably conveyed to the heating member.

FIG. 2 is a diagram illustrating a schematic structure of a coating apparatus according to the first embodiment. It is a perspective view of a joined article. It is a perspective view explaining the application process of an adhesive. FIG. 7 is a diagram illustrating a schematic structure of a coating apparatus according to a second embodiment.

  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 embodiments is merely an example in nature, and is not intended to limit the present invention, its application, or its use.

(Embodiment 1)
FIG. 1 shows a schematic structure of a coating apparatus 2 used in a method for coating an adhesive 1 according to a first embodiment of the present invention. The pressure-sensitive adhesive 1 is formed in an elongated shape, and has a string shape in this embodiment. The length of the adhesive 1 can be set to, for example, about several tens to several hundreds of meters. It is preferable that the length of the adhesive 1 be long.

  FIG. 2 shows a bonded article 10 obtained by using the adhesive 1. The bonded product 10 is used as, for example, a cosmetic case, a housing or exterior member for electric appliances, a mobile terminal, a mobile phone, a smartphone, or the like. One member 11 and a back member (second member) 12 constituting the back side are superimposed, and a design layer is provided on the back surface of the light transmitting member 11 so as to appear on the front side. The light transmitting member 11 and the back side member 12 are joined by the adhesive 1.

  In this embodiment, a case will be described in which the joint product 1 is an electronic device such as a smartphone or a wearable device. Although not shown, the translucent member 11 is provided with a display screen including a liquid crystal display panel or the like, and constitutes a display panel. Further, a light source is provided inside the joint product 10. Examples of the light source include a backlight light source for a liquid crystal display panel and a light source for transmitting and illuminating an operation button provided on a part of the light transmitting member 11 from behind.

  The back side member 12 is a member such as a housing made of a material having a laser light impermeability that does not transmit laser light having a wavelength of 800 nm or more and 1500 nm or less.

  Here, the laser light transmittance refers to a property of transmitting the laser light of the above-described wavelength, and a property of transmitting 15% or more of the laser light as a heating source, and transmits all of the laser light of the above-described wavelength. Including things. Materials having such properties include, for example, materials such as plastic, glass, and thin metal oxide films such as ITO. Conversely, non-transmissive laser light means absorbing or reflecting laser light of the above wavelength, and the property of partially transmitting and / or reflecting laser light of the above wavelength as a heating source but absorbing the rest. And includes those that absorb all of the laser light. Examples of the material having such properties include, in addition to metals and ceramics, materials obtained by mixing an organic pigment, an inorganic pigment, a dye, a reinforcing glass fiber, and the like with resin or rubber. In the present embodiment, the back member 12 is made of a resin material containing a coloring pigment and reinforcing glass fiber. 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 laser light in the infrared region.

  The light-transmitting member 11 is a plate-shaped member made of a material that is colorless and transparent and has a laser light transmitting property of transmitting a laser beam having the above-described wavelength. In other words, the light transmitting member 11 transmits the laser light of the above-described wavelength as a heating source with little reflection or absorption, or does not melt even when partially transmitting and / or reflecting the laser light of the above-described wavelength. The light transmitting member 11 has a property of transmitting the remaining laser light, and may have a property of transmitting all of the laser light having the above wavelength.

  The light transmitting member 11 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), ethylene tetrafluoroethylene copolymer, liquid crystal polymer, polybutylene terephthalate, polyetheretherketone, polyetherketone, polyetherketoneketone, Examples thereof include polyethylene naphthalene, polyethylene terephthalate, polyimide, polyacetal, polyamide imide, polyphenylene ether, polyphenylene oxide, polyphenylene sulfide, polysulfone, polythioethyl sulfone, polytetrafluoroethylene, polyether sulfone, and polyether imide.

  In addition, it also 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 , A nylon-modified olefin resin, an epoxy-modified resin, an ethylene vinyl alcohol resin (EVOH), an ethylene vinyl acetate resin, a resin such as a hot melt adhesive resin, and the like or a mixture or combination of the above thermoplastic resins. .

  The light transmitting member 11 may be a thermoplastic elastomer, and specifically, a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a PVC-based elastomer, a polyamide-based elastomer, a polybutadiene-based elastomer, an isoprene-based elastomer, and an ion cluster. And amorphous PE elastomers (product example: DuPont-Mitsui Polychemicals Himiran), chlorinated PE and amorphous PE elastomers (product example: Miraplane manufactured by Mitsubishi Chemical), fluorine elastomer, polyurethane elastomer And acrylic elastomers.

  The light transmitting member 11 may be a thermosetting resin, and specific examples thereof include a phenol resin, a urea resin, a melamine resin, an epoxy resin, and an unsaturated polyester resin.

  Further, the light transmitting member 11 may be made of a composite resin made by mixing a reinforcing material or a filler with the thermoplastic resin or the thermosetting resin described above.

  For the above resins and elastomers, for example, heat stabilizers, antioxidants, ultraviolet stabilizers, conductive agents, nucleating agents, release agents, flame retardants, antistatic agents, processing preparations, coloring 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 a color pigment or a dye is mixed, the amount is set to such an extent that a predetermined laser light transmittance can be secured.

  The translucent member 11 may be made of, for example, soda-lime glass, lead glass, borosilicate glass, or the like, in addition to the above resin. Further, it may be tempered glass, laminated glass, laminated glass, or the like. The translucent member 10 is not limited to colorless, but may be lightly colored as long as the translucent member 10 has translucency so that the design layer can be seen from the front side.

  The thickness of the back side member 12 and the light transmitting member 11 is about 0.1 mm to 3 mm, depending on the type of the joint product 10 and the like.

  A design layer is provided on the surface on the back member 12 side, which is the back surface of the light transmitting member 11, so that the design appears on the front side of the light transmitting member 11. This design layer is formed of a printed coating film formed by attaching an ink containing a dye or a pigment to the back surface of the light transmitting member 11. For example, when a smartphone, a tablet, or a liquid crystal television is the bonded product 1, Has a frame shape that can be viewed from the front side of the light transmitting member 11 like a frame portion of a display panel for improving the appearance of the display screen.

  For the curable compound of the ink constituting the design layer, for example, acrylate, urethane acrylate, epoxy acrylate, carboxyl group-modified epoxy acrylate, polyester acrylate, unsaturated polyester resin, copolymer acrylate, polyacryl acrylate, alicyclic epoxy Resins, glycidyl ether epoxy resins, vinyl ether compounds, oxetane compounds, and the like.

  Examples of the curable ink include a natural drying curing type, a heat curing 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 may be any dye that does not transmit laser light of the above wavelength, and may be of any type, such as natural dyes such as red and safflower, synthetic dyes such as reaction, sulfuration and naphthol, and fluorescent dyes. The pigment may be any pigment that does not transmit laser light of the above-mentioned wavelength, and examples thereof include inorganic pigments such as carbon black and composite oxide pigments, phthalocyanine pigments, azo pigments, lake pigments, and many others. Organic pigments such as cyclic pigments may be mentioned, and various pigments having non-transmittance corresponding to the wavelength of the laser beam having the above wavelength can be used. By forming the design layer with a printed coating film, a fine design can be obtained. As a printing method, for example, various printing methods such as letterpress printing, intaglio printing, flexographic printing, offset printing, silk printing, gravure printing, laser printing, and inkjet printing can be used.

  Further, the design constituted by the design layer has various forms such as a line, a character, a figure, a symbol, a picture, a gradation pattern, a solid color fill, or a combination thereof. In addition, the thickness of the design layer is, for example, 1 μm or more and 50 μm or less, but is not limited to this range. Further, as the laser light impermeability in the design layer, for example, the transmittance of the laser light having the above wavelength is preferably less than 15%, and the transmittance of the laser light having the wavelength of 940 nm is preferably less than 15%. More preferred.

  Incidentally, the design layer can be formed by, for example, attaching a vapor-deposited film or a film, applying a primer, or the like, in addition to the one formed by the printed coating film as described above. In the case of a vapor-deposited film, the design layer becomes extremely thin. Further, the entire design layer does not need to be non-transparent to laser light, and only a part corresponding to the joint between the back member 12 and the translucent member 11 may be non-transparent to laser light.

  The diameter of the pressure-sensitive adhesive 1 used for joining the back member 12 and the light transmitting member 11 is set to 0.5 mm or more and 5.0 mm or less. If the diameter of the pressure-sensitive adhesive 1 is smaller than 0.5 mm, it becomes difficult to feed the pressure-sensitive adhesive 1, and the width of the pressure-sensitive adhesive 1 applied to a bonding surface during the production of a bonded product described later may be too narrow. , It is difficult to ensure the joint strength and waterproofness. On the other hand, if the diameter of the pressure-sensitive adhesive 1 is larger than 5.0 mm, the residence time of the pressure-sensitive adhesive 1 in the heating member 21 to be described later becomes longer, and the pressure-sensitive adhesive 1 may be thermally degraded, which is not preferable. Therefore, the diameter of the pressure-sensitive adhesive 1 is preferably 0.5 mm or more and 5.0 mm or less. More preferably, the diameter of the pressure-sensitive adhesive 1 is 3.0 mm or less. The cross-sectional shape of the adhesive 1 may be a circular shape, an elliptical shape, or a polygonal shape.

The pressure-sensitive adhesive 1 is obtained by mixing at least a thermoplastic elastomer or unvulcanized rubber and a tackifier, and molding the mixture. That is, the pressure-sensitive adhesive 1 is mainly composed of a polymer compound (elastomer) exhibiting rubber elasticity at around normal temperature and its alloy, and has thermoplasticity. Characteristics of the adhesive 1, the value obtained by DMA (dynamic viscoelasticity measuring method), preferably 10 ⁴ or more ¹⁰ 8 Pa or less, and more preferably not more than 10 ⁵ or more ¹⁰ 7 Pa.

  Examples of the thermoplastic elastomer constituting the pressure-sensitive adhesive 1 include styrene-based elastomer, olefin-based elastomer, polyester-based elastomer, vinyl chloride-based elastomer, polyamide-based elastomer, polybutadiene-based elastomer, isoprene-based elastomer, ion cluster and amorphous PE Elastomers, fluorine-based elastomers, urethane-based elastomers, acrylic-based elastomers, and the like can be given, and these can be used alone or in combination. In particular, styrene-based elastomers are preferable because of their excellent adhesive strength, but have the property of being easily thermally degraded as compared with other elastomers.

Non-vulcanized rubber can be used instead of the thermoplastic elastomer constituting the pressure-sensitive adhesive 1, or together with the thermoplastic elastomer. Examples of the unvulcanized 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 rubber, nitrile rubber, hydrogenated nitrile rubber and the like.

Specific examples of the tackifier for imparting tackiness to the adhesive 1 include, for example, unmodified rosins (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, which are rosin-based tackifying resins, Rosin modified by hydrogenation, disproportionation, polymerization, etc. of unmodified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins) And the like. 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 rosins and modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acids; rosins modified with unsaturated fatty acids; 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; such as unmodified rosin, modified rosin, and various rosin derivatives Emissions such (in particular, rosin esters) and the like metal salts of. Further, as the rosin derivative, a rosin phenol resin obtained by adding phenol to a rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and subjecting to thermal polymerization can also be used. Examples of the terpene-based tackifying resin include terpene-based resins such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and modified terpene-based resins (phenol modification, aromatic modification, hydrogenation modification). Terpene-based resins (e.g., terpene-phenol-based resins, styrene-modified terpene-based resins, aromatic-modified terpene-based resins, hydrogenated terpene-based resins, etc.).

  Examples of the hydrocarbon-based tackifying resin include aliphatic hydrocarbon resins [olefins having 4 to 5 carbon atoms and olefins (olefins such as butene-1, isobutylene and pentene-1; butadiene, 1,3-pentadiene, isoprene). Polymers such as aliphatic hydrocarbons such as diene, etc.), aromatic hydrocarbon resins [vinyl group-containing aromatic hydrocarbons having 8 to 10 carbon atoms (styrene, vinyltoluene, α-methylstyrene) , Indene, methylindene, etc.), an aliphatic cyclic hydrocarbon resin [a so-called “C4 petroleum fraction” or “C5 petroleum fraction” is cyclo-dimerized and then polymerized and alicyclic. Hydrocarbon resin, polymer of cyclic diene compound (cyclopentadiene, dicyclopentadiene, ethylidene norbornene, dipentene, etc.) or hydrogenated product thereof, aromatic Alicyclic hydrocarbon resins obtained by hydrogenating the aromatic ring of hydrocarbon resins and aliphatic / aromatic petroleum resins, etc.], aliphatic / aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic -Various hydrocarbon resins such as alicyclic petroleum resins, hydrogenated hydrocarbon resins, cumarone resins, and cumarone indene resins. The oil may be selected from paraffinic, naphthenic, and aroma oils which are roughly classified.

The liquid oligomer is selected from acrylic, styrene, rubber such as polyisoprene and butadiene, polyester, and other high viscosity polymers having a molecular weight of about several hundreds to several thousands. Others are selected from the group consisting of heat stabilizers, antioxidants, ultraviolet stabilizers, conductive agents, nucleating agents, mold release agents, flame retardants, antistatic agents, processing agents, plasticizers and vulcanizing agents, if necessary. Preferably, at least one is used.

The softening point and melting point of the pressure-sensitive adhesive 1 depend on the composition of the pressure-sensitive adhesive 1. In other words, the softening point and the melting point of the pressure-sensitive adhesive 1 can be changed to some extent depending on the type of the thermoplastic elastomer that is the base resin of the pressure-sensitive adhesive 1. In this embodiment, the range of the softening point and the melting point of the pressure-sensitive adhesive 1 is set to be 120 ° C. or higher and 230 ° C. or lower.

  Although not an essential component, the adhesive 1 may be mixed with a laser light absorber. As the laser light absorber, for example, organic dyes and organic pigments, commercially available laser light absorbers, specifically, carbon black, lamp black, bone black, graphite and the like for inorganic substances, titanium black for metal oxides, There are manganese dioxide, titanium dioxide and the like. In addition, a meanine dye, a thionylnickel complex, a squarilinium dye, a polymethine dye, an immonium dye, a phthalocyanine dye, a triallylmethane dye, a naphthoquinoshi dye, and the like can also be used. These can be used alone or as a mixture.

  The laser light absorbing property of the pressure-sensitive adhesive 1 can be arbitrarily set depending on the type and the amount of the laser light absorbing agent. The laser light absorptivity of the pressure-sensitive adhesive 1 can be set to 30% or more and 100% or less. The preferable range of the laser light absorption of the pressure-sensitive adhesive 1 is 50% or more and 100% or less.

  The surface of the adhesive 1 is subjected to an anti-adhesion treatment. The anti-adhesion treatment is a treatment for preventing the adhesives 1 from adhering to each other when the adhesives 1 are stored, and for preventing the adhesives 1 from adhering to other members and the like. For example, it can be achieved by adhering an anti-adhesive which physically suppresses adhesion to the surface of the adhesive 1. Examples of the anti-adhesive include, for example, those obtained by mixing any one or more selected from the group consisting of metal soaps, flaky clay minerals, and inorganic fine particles (eg, silica particles). The group may include a surfactant. The metal soap is, for example, a metal salt of an aliphatic carboxylic acid. As will be described later, since the pressure-sensitive adhesive 1 is stored in a rolled state, a particularly preferable anti-adhesive agent capable of effectively preventing mutual adhesion in this state is a flaky clay mineral such as talc, Examples thereof include silica particles which are spherical inorganic fine particles. In particular, since spherical silica particles have high slipperiness when rubbed, it is possible to effectively prevent cohesion of the pressure-sensitive adhesive 1 during storage. The anti-adhesive agent is not limited to the above-described one, and may be a powder or a liquid as long as it can prevent mutual adhesion of the adhesive 1 during storage. Further, a powdery and a liquid anti-adhesive agent may be mixed and used.

  Although the properties of the pressure-sensitive adhesive 1 are not essential, for example, the light transmittance at a wavelength of 400 nm or more and less than 800 nm is 30% or less, and the light transmittance (infrared laser light transmittance) at a wavelength of 800 nm to 1500 nm is 60%. % May be provided. In order to obtain the pressure-sensitive adhesive 1 having such light transmittance, it is preferable to add an organic pigment or the like. Examples of the organic pigment include bisbenzofuranone-based pigments, azomethine-based pigments, and berylen-based pigments as infrared-transmissive black pigments. Of these, bisbenzofuranone pigments are most preferred. Examples of colored organic pigments include CI Pigment Orange 2, 5, 13, 16, 31, 31, 34, etc., CI Pigment Red 1, 2, 3, 4, 5, etc., CI Pigment Green 7, 10, 36, 37, 58. CI Pigment Violet 1, 19, 23, 27, 32, etc., CI Pigment Blue 1, 2, 15, 16, 22, 22 etc. and derivatives thereof may be used in combination of two or more. A black dye may be used in order to obtain a pressure-sensitive adhesive 1 having a light transmittance of 30% or less with a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more with a wavelength of 800 nm or more and 1500 nm or less. Examples of the dye include acid dyes Acid Black 1, 2, 24, and 48.

  The following is used as a coloring dye capable of obtaining the pressure-sensitive adhesive 1 having a light transmittance of 30% or less with a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more with a wavelength of 800 nm or more and 1500 nm or less. Can be. Chemical structures include pyrazole azo, anilino azo, triphenylmethane, anthraquinone, anthrapyridone, benzylidene, oxole, pyrazolotriazole azo, pyridone azo, cyanine, phenothiazine, pyrrolopyrazole azomethine, xathene Phthalocyanine, benzopyran, indigo, pyrromethene, triarylmethane, azomethine, berylene, perinone, quatarylene, quinophthalone dyes, etc., and acid dyes, direct dyes, basic dyes, mordants Two or more dyes, acid mordant dyes, azoic dyes, disperse dyes, oil-soluble dyes, food dyes and derivatives thereof can be used as a mixture.

  Since the infrared laser light having the above wavelength has a long wavelength, it is difficult to receive Rayleigh scattering and Mie scattering, and 100 nm to 500 nm of bismuth sulfide powder or 5 nm to 50 nm of nanoparticles made of silver or tin or an alloy thereof are added to form the adhesive 1. Can be black. Further, an organic pigment and a dye can be used in combination, and the pressure-sensitive adhesive 1 can be obtained by containing at least one of an inorganic pigment, an organic pigment and a dye.

  In order to whiten the pressure-sensitive adhesive 1 having visible light reflectivity, the following materials can be used alone or as a mixture or dispersed or dissolved in the materials.

  The white inorganic pigment which can obtain the pressure-sensitive adhesive 1 having a light transmittance of 30% or less with a wavelength of 400 nm or more and less than 800 nm and a light transmittance of 60% or more with a wavelength of 800 nm or more and 1500 nm or less includes infrared ray. Inorganic pigment that is less susceptible to scattering and Mie scattering and reflects visible light of 400 nm or more and less than 800 nm, that is, titanium dioxide particles, magnesium oxide particles having a particle diameter of not more than half the wavelength of infrared rays and 100 nm to 400 nm, magnesium oxide particles, and sulfuric acid. Examples include inorganic pigments containing barium particles, basic lead carbonate particles, zinc oxide particles, and the like. These inorganic pigments can be added and dispersed in a solvent to whiten.

  The pressure-sensitive adhesive 1 has a property of transmitting visible light, that is, has a visible light transmittance, and the visible light transmittance is 30% or less, more preferably 20% or less at a wavelength of 400 nm or more and less than 800 nm. If the visible light transmittance of the adhesive 1 is higher than 30%, the light of the backlight light source inside the joint 1 leaks from the joint between the light transmitting member 11 and the back member 12 and the display quality of the liquid crystal display panel or the like. Is undesirably reduced.

  The pressure-sensitive adhesive 1 has a property of transmitting infrared laser light, that is, laser light transmittance, and has a laser light transmittance of 60% or more, more preferably 80% or more at a wavelength of 800 nm or more and 1500 nm or less. If it is less than 60%, most of the laser light is absorbed by the pressure-sensitive adhesive 1, and the laser light does not sufficiently reach the back member 12 at the time of bonding, which will be described later. 1 is not preferable because it does not sufficiently melt or soften.

In order to disperse the organic or inorganic pigment particles in the material of the pressure-sensitive adhesive 1, a general bead mill, three-roll mill, colloid mill, high-speed rotation mill, or the like can be used. In particular, it is necessary to monodisperse particles having a small particle diameter as much as possible in a solvent in order to make infrared rays hardly subjected to Rayleigh scattering and Mie scattering. A surfactant, a polymer resin or the like can be used as a protective colloid in order to obtain a stable dispersion state by assisting the dispersion of the particles. When a dye is used, it can be used by dissolving it in an appropriate solvent.

The amount of the pigment or dye added depends on the coloring material, but if it can be adjusted so that the light transmittance at a wavelength of 400 nm or more and less than 800 nm is 30% or less, and the light transmittance at a wavelength of 800 nm or more and 1500 nm or less is 60% or more. Good.

  Next, the configuration of the coating device 2 will be described. The coating device 2 includes a winding member 20 for winding and storing the adhesive 1, a heating member 21 for heating the adhesive 1 before coating, and a feeding device for feeding the adhesive 1 to the heating member 21. 22. The winding member 20 is formed of a reel capable of winding the adhesive 1 having a length of about several tens to several hundreds of meters, and is supported so as to rotate around a support shaft (not shown). .

  The heating member 21 can be made of, for example, a tubular block material. As a material of the heating member 21, a material having high thermal conductivity is preferable, and examples thereof include aluminum alloy, copper, and ceramics of high thermal conductivity nitride (aluminum nitride, boron nitride, and the like).

  At the lower end of the heating member 21, a nozzle 21a is formed so as to protrude. The heating member 21 has a discharge hole 21b penetrating from the upper end to the lower end of the nozzle 21a. The cross-sectional area of the discharge hole 21b is gradually reduced so that the inner diameter becomes smaller as approaching the lower end (tip), and the inner surface is tapered without any steps. The opening diameter at the upper end of the discharge hole 21b is set to be larger than the diameter of the pressure-sensitive adhesive 1 to be fed, for example, twice or more the diameter of the pressure-sensitive adhesive 1. Thereby, it becomes easy to feed the adhesive 1 into the inside of the discharge hole 21b. On the other hand, the opening diameter of the lower end of the discharge hole 21b is set smaller than the diameter of the adhesive 1 to be fed, for example, 0.9 times or less of the diameter of the adhesive 1. This makes it possible to narrow the application width of the adhesive 1. That is, the application width of the pressure-sensitive adhesive 1 can be changed depending on the opening diameter of the lower end of the ejection hole 21b. The opening diameter of the lower end of the discharge hole 21b may be substantially the same as the diameter of the pressure-sensitive adhesive 1 to be fed.

  The nozzle 21a is detachably attached to the main body of the heating member 21. For example, when changing the opening diameter of the lower end of the discharge hole 21b, it is possible to easily cope with changing the nozzle 21a having a different diameter without changing the main body of the heating member 21.

  The heating member 21 is provided with a vent (not shown) for releasing the air inside the discharge hole 21b. Thereby, the entry of air into the adhesive 1 is suppressed.

  The heating member 21 is provided with a cartridge heater 24 as heating means. The cartridge heater 24 is connected to the control device 25 and has a heating element that generates heat by electric power supplied from the control device 25. The amount of heat generated per unit time of the cartridge heater 24 is controlled by the controller 25. Incidentally, a heater other than the cartridge heater 24 can be used as the heating means. The heater may be provided on the upper surface of the heating member 21, so that the pressure-sensitive adhesive 1 is heated near the discharge hole 21b immediately before being discharged from the discharge hole 21b.

  Further, the heating member 21 is provided with a thermocouple 26 as a temperature detection sensor. The thermocouple 26 is connected to a control device 25, which can detect the temperature of the heating member 21, that is, the temperature of the inner surface of the discharge hole 21b.

  The control device 25 is provided with a temperature setting unit 25a. The temperature setting section 25a is for the user to arbitrarily set the temperature of the inner surface of the discharge hole 21b. In the temperature setting section 25a, the temperature of the inner surface of the discharge hole 21b can be set in a temperature range of, for example, 140 ° C. or more and 300 ° C. or less. The control device 25 is configured to supply electric power to the cartridge heater 24 based on the temperature detection result by the thermocouple 26 so that the temperature of the inner surface of the discharge hole 21b becomes the temperature set by the temperature setting unit 25a. ing.

  The feeding device 22 includes a tubular member 27, a motor 28, and a transport screw 29. The tubular member 27 extends vertically. The lower end of the tubular member 27 is connected to and communicates with the upper end of the discharge hole 21 b of the heating member 21. Above the upper end of the tubular member 27, a motor 28 is provided. The motor 28 is supported by a support member (not shown), so that the adhesive 1 can be put into the tubular member 27 from between the motor 28 and the upper end of the tubular member 27. The output shaft of the motor 28 extends in the up-down direction and is arranged substantially concentrically with the center of the tubular member 27.

  The upper end of the transport screw 29 is fixed to the output shaft of the motor 28. The transport screw 29 is formed by spirally forming a plate material, and is configured to be able to pressure-feed the adhesive 1 downward, that is, into the discharge hole 21 b of the heating member 21 by rotation of the motor 28. I have. The motor 28 is connected to the control device 25, and the transport speed of the adhesive 1 can be adjusted by changing the rotation speed of the motor 28 by the control device 25. The user can arbitrarily set the transport speed of the adhesive 1.

  Next, the procedure for applying the pressure-sensitive adhesive 1 will be described. First, the pressure-sensitive adhesive 1 is manufactured. When producing the pressure-sensitive adhesive 1, the above-mentioned materials are kneaded with a twin-screw extruder, mixed and extruded with a straight die to obtain a string-shaped pressure-sensitive adhesive 1. This is the step of forming the pressure-sensitive adhesive 1.

  After the molding step, the process proceeds to an adhesion-preventing treatment step of performing an anti-adhesion treatment on the surface of the pressure-sensitive adhesive 1 molded in the molding step. In the anti-adhesion treatment step, the above-described anti-adhesion agent is attached to the entire surface of the pressure-sensitive adhesive 1.

  Thereafter, the process proceeds to a storage step of storing the pressure-sensitive adhesive 1 subjected to the anti-adhesion treatment in the anti-adhesion treatment step until use. In the storage step, the pressure-sensitive adhesive 1 is wound around the winding member 20. Thereby, the adhesive 1 is stored neatly. At this time, since the pressure-sensitive adhesive 1 has elasticity, the pressure-sensitive adhesives 1 come into close contact with each other. Can be stored in a usable state. Further, the adhesive 1 does not adhere to the winding member 20.

  Then, the process proceeds to a coating process. In the application step, the pressure-sensitive adhesive 1 stored in the storage step is fed to the heating member 21 having the discharge holes 21b and heated inside the discharge holes 21b or in the vicinity of the discharge holes 21b to be softened or melted to discharge the pressure-sensitive adhesive. The ink is discharged from the hole 21b and applied to the back surface (joining surface) of the design layer of the light transmitting member 11. That is, the pressure-sensitive adhesive 1 wound by the winding member 20 is put into the inside from the upper end of the tubular member 27, and the motor 28 is operated to rotate the transport screw 29. By the rotation of the transport screw 29, the adhesive 1 wound by the winding member 20 is pulled and sent downward. At this time, since the adhesive 1 has been subjected to the anti-adhesion treatment, the adhesive 1 can be sent smoothly.

  The sent adhesive 1 reaches the discharge hole 21 b of the heating member 21. The adhesive 1 that has reached the discharge hole 21b is heated or softened or melted by the heat of the inner surface of the discharge hole 21b. The temperature of the inner surface of the discharge hole 21b may be the softening point or the melting point of the pressure-sensitive adhesive 1, but is preferably set to 140 ° C or higher and 300 ° C or lower, and particularly preferably. 180 ° C. or less. When the pressure-sensitive adhesive 1 is heated to a temperature higher than 180 ° C., the heat history tends to be accumulated in the resin component. Because it is gone.

  Further, it is preferable that the time during which the pressure-sensitive adhesive 1 is heated and held at that temperature, that is, the heating and holding time is 1 second to 10 seconds. If the heating and holding time is shorter than 1 second, uneven heating is likely to occur and uniform application becomes difficult, and if the heating and holding time is longer than 10, heat history is easily accumulated in the resin component. .

  Since the pressure-sensitive adhesive 1 is pushed into the discharge hole 21b by the transport screw 29, the shear rate increases, and the shear viscosity decreases. Thereby, the coating speed increases. When applying the adhesive 1, the nozzle 21a may be moved or the light transmitting member 11 may be moved. In the application step, the width of the pressure-sensitive adhesive 1 applied to the light transmitting member 11 is set to 0.2 mm or more and 1.0 mm or less, and the height of the pressure-sensitive adhesive 1 with respect to the bonding surface is set to 50 μm or more and 500 μm or less. The width and height of the adhesive 1 can be adjusted by adjusting the application speed. The higher the application speed, the narrower the width of the adhesive 1 and the lower the height. Also, the width and height of the adhesive 1 can be adjusted depending on the shape of the nozzle 21a.

  By setting the width of the pressure-sensitive adhesive 1 to 0.2 mm or more and 1.0 mm or less, a frame can be narrowed when a housing of an electronic device or the like and a display panel are joined. By setting the height of the adhesive 1 to 50 μm or more, the followability of the adhesive 1 to the joint surface is ensured.

  The translucent member 11 on which the adhesive 1 is applied is superimposed on and adhered to the back member 12, thereby obtaining the joined product 10 in which the translucent member 11 and the back member 12 are joined by the adhesive 1. After the translucent member 11 is overlaid on the back member 12, the adhesive 1 may be softened or melted by irradiating the adhesive 1 with laser light from the translucent member 11 side. In this case, higher bonding strength can be obtained. Irradiation with laser light is not indispensable, and a hot press or the like can be used as a heating means for the adhesive 1 other than irradiation with laser light.

  As described above, according to the first embodiment, since the elongate string-shaped adhesive 1 molded in the molding step is subjected to the anti-adhesion treatment, the adhesives 1 do not stick to each other in the storage step. , Good storage stability. Then, by feeding the stored pressure-sensitive adhesive 1 to the heating member 21, the pressure-sensitive adhesive 1 is heated or softened or melted in or near the discharge hole 21 b. By heating in the vicinity of the discharge hole 21b in this manner, the time during which the adhesive 1 is in the heated state is shorter than in the case where the adhesive 1 is heated in a state in which the adhesive 1 is accommodated in a syringe as in the conventional example. Therefore, the pressure-sensitive adhesive 1 is less susceptible to heat history, so that gelation of the resin component is suppressed and a decrease in bonding strength after bonding is suppressed. In addition, by forming the pressure-sensitive adhesive 1 in an elongated shape in advance in the forming step, it is possible to sufficiently narrow the application width of the pressure-sensitive adhesive 1, and for example, when the pressure-sensitive adhesive 1 is applied to an electronic device having a display panel, it becomes more difficult. The frame can be further narrowed. Further, since the softened or melted pressure-sensitive adhesive 1 is applied to the joint surface, even if the joint surface has a complicated shape, it can be easily applied so as to follow the shape. Further, since the use of an organic solvent as in the solvent dissolving method is unnecessary, the working environment and workability are improved. In addition, when the adhesive is applied, the stored amount of the adhesive 1 may be fed to the heating member 21 in a necessary amount, so that the adhesive which is discarded is compared with the case where a conventional sheet-shaped adhesive is punched out. Is significantly reduced, and the cost can be reduced.

(Embodiment 2)
FIG. 4 is a diagram illustrating a schematic structure of a coating apparatus according to Embodiment 1 according to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in that the pressure-sensitive adhesive 1 is fed to the heating member 21 using a belt-type conveyance method, and the other parts are the same as the first embodiment. Therefore, hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The portions different from the first embodiment will be described in detail.

  In the second embodiment, a belt-type feeding device is used as the feeding device 30 for feeding the adhesive 1 to the heating member 21. That is, the feeding device 30 according to the second embodiment rotates the first belt 31, the second belt 32, the driving gear 33, the driven gear 34, the first to sixth pulleys 41 to 46, and the driving gear 33. And a motor 50 for driving. The first belt 31 and the second belt 32 have an endless shape, that is, a loop, and have the same circumferential length as each other, and constitute a first endless member and a second endless member of the present invention, respectively. The higher the friction coefficient of the surfaces of the first belt 31 and the second belt 32, the better. Further, the surface roughness of the first belt 31 and the second belt 32 may be increased. As a result, slippage between the surfaces of the first belt 31 and the second belt 32 and the adhesive 1 is eliminated. Note that, instead of the first belt 31 and the second belt 32, for example, an endless band-shaped member or the like may be used.

  The driving gear 33 and the driven gear 34 are arranged to be separated upward from the heating member 21. The drive gear 33 is rotatably supported by a rotation shaft 33a. The rotational force of the motor 50 is transmitted to the drive gear 33. The rotational force of the motor 50 can be transmitted by, for example, a well-known gear, timing belt, chain, or the like. The driven gear 34 is rotatably supported by a rotation shaft 34a. The driven gear 34 and the driving gear 33 are engaged with each other, and the rotational force of the driving gear 33 is transmitted to the driven gear 34.

  The first pulley 41 is integrated with the drive gear 33, and is rotatable with the drive gear 33 around the rotation shaft 33a. The second pulley 42 is disposed to be spaced downward from the first pulley 41, and is rotatably supported by a rotating shaft 42a. The third pulley 43 is disposed below and spaced apart from the second pulley 42, and is rotatably supported by a rotating shaft 43a.

  Further, the fourth pulley 44 is integrated with the driven gear 34, and is rotatable with the driven gear 34 around the rotation shaft 34a. The fifth pulley 45 is disposed below and spaced apart from the fourth pulley 44, and is rotatably supported by a rotating shaft 45a. The sixth pulley 46 is disposed below and spaced apart from the fifth pulley 45, and is rotatably supported by a rotating shaft 46a.

  The first belt 31 is wound around the first pulley 41, the second pulley 42, and the third pulley 43, and the first pulley 41 is rotated by the rotation of the driving gear 33, so that the first belt 31 is sent. When the first belt 31 is fed, the second pulley 42 and the third pulley 43 rotate. Thus, the first belt 31 is driven to circulate so as to pass through a predetermined path.

  Further, the second belt 32 is wound around the fourth pulley 44, the fifth pulley 45, and the sixth pulley 46, and the rotation of the driven gear 34 causes the rotation of the fourth pulley 44 to feed the second belt 32. When the second belt 32 is fed, the fifth pulley 45 and the sixth pulley 46 rotate. Thus, the second belt 32 is driven to circulate so as to pass through a predetermined path. The first belt 31 and the second belt 32 may be, for example, timing belts.

  The first pulley 41 and the fourth pulley 44 have substantially the same height, the second pulley 42 and the fifth pulley 45 have substantially the same height, and the third pulley 43 and the sixth pulley 44 have the same height. The height at 46 is substantially the same. The horizontal interval between the first pulley 41 and the fourth pulley 44 is the horizontal interval between the second pulley 42 and the fifth pulley 45, and the horizontal interval between the third pulley 43 and the sixth pulley 46. It is set wider than the interval. The horizontal distance between the second pulley 42 and the fifth pulley 45 and the horizontal distance between the third pulley 43 and the sixth pulley 46 are set to be substantially the same. The horizontal direction of the second pulley 42 and the fifth pulley 45 is set such that the surfaces of the first belt 31 and the second belt 32 contact the adhesive 1 disposed between the first belt 31 and the second belt 32. The interval and the horizontal interval between the third pulley 43 and the sixth pulley 46 are set.

  By disposing the first to sixth pulleys 41 to 46 as described above, the first belt 31 is placed in a state where the surface of the first belt 31 and the surface of the second belt 32 face each other. The 31 and the second belt 32 are circulated and driven synchronously. The driving direction of the first belt 31 and the second belt 32 is a direction in which the adhesive 1 disposed between the first belt 31 and the second belt 32 can be fed downward as indicated by an arrow in FIG. It is. Then, above the second pulley 42 and the fifth pulley 45, the first belt 31 and the second belt 32 are arranged such that the distance between them in the horizontal direction becomes longer as going upward. The distance between the upper portions of the first belt 31 and the second belt 32 is set to be longer than the diameter of the adhesive 1.

  On the other hand, below the second pulley 42 and the fifth pulley 45, the first belt 31 and the second belt 32 are arranged such that their horizontal separation distances are substantially the same. The distance between the first belt 31 and the second belt 32 below the second pulley 42 and the fifth pulley 45 is set to be slightly shorter than the diameter of the adhesive 1. Accordingly, the adhesive 1 can be fed across the predetermined length in the radial direction on the surfaces of the first belt 31 and the second belt 32, so that the adhesive 1 can be supplied as compared with the case of feeding by point contact. The pressure-sensitive adhesive 1 is less likely to buckle and deform when the agent 1 is fed, so that the pressure-sensitive adhesive 1 can be fed stably. In addition, by increasing the friction coefficient of the surfaces of the first belt 31 and the second belt 32, the adhesive 1 is less likely to slip on the surfaces of the first belt 31 and the second belt 32. It can be sent reliably.

  As described above, according to the second embodiment, by heating the adhesive 1 fed by the feeding device 30 in the vicinity of the discharge hole 21b, the time during which the adhesive 1 is in the heating state is short. Therefore, the pressure-sensitive adhesive 1 is less susceptible to heat history, so that gelation of the resin component is suppressed and a decrease in bonding strength after bonding is suppressed.

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

(Manufacture of adhesive)
The material of the adhesive was 60 parts by weight of Asaprene T-438, a styrene-based thermoplastic elastomer SBS (styrene-butadiene-styrene copolymer), 40 parts by weight of JSR TR2601, a styrene-based thermoplastic elastomer SBS, and adhesiveness. 30 parts by weight of T-130, which is a terpene phenol resin as an imparting agent, 15 parts by weight of T-160, which is a terpene phenol resin, and 1 part by weight of Adeka AO-60, which is a phenolic antioxidant. These materials were heated to 160 ° C. with a twin-screw extruder, kneaded sufficiently without unevenness, and extruded with a straight die to form a string-shaped adhesive.

  Then, after putting the adhesive in a cooling tank in which water added with Mold GP-7 manufactured by Ongaku Yushi Kogyo Co., Ltd., Admatech SO-C5 which is silica particles as an anti-adhesive is sprayed on the adhesive. And dried with a dryer to perform an anti-adhesion treatment.

  The adhesive after the anti-adhesion treatment was wound around a winding member and stored. The diameter of the adhesive is 3 mm.

(Application of adhesive)
The adhesive wound on the winding member as described above was fed to the discharge hole of the heating member, heated, and applied to the joint surface. The feeding device may be the conveying screw 29 of the first embodiment or the belt type of the second embodiment.

  As shown in Table 1, the heating temperature of the adhesive was set at 120 ° C., 140 ° C., 160 ° C., 180 ° C., 230 ° C., and 250 ° C., respectively, and applied. The heating time is all 3 seconds.

  When the heating temperature was in the range of 120 ° C. to 230 ° C., almost no thermal deterioration of the resin component of the pressure-sensitive adhesive was observed. When the heating temperature is low at 120 ° C., the viscosity of the pressure-sensitive adhesive is high, and it is necessary to reduce the application speed to 1 mm / sec in order to apply continuously without interruption. Further, when the pressure-sensitive adhesive was heated to 250 ° C., the thermal deterioration of the resin component became remarkable and the color changed, and the discharge holes were clogged, and the coating speed was reduced to 1 mm / sec. Considering the application speed and thermal deterioration, it is understood that the heating temperature range is preferably 140 ° C. or higher and 230 ° C. or lower.

  The embodiments described above are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention can be used, for example, when manufacturing cosmetic cases, housing members or exterior members for electric appliances, mobile terminals, mobile phones, smartphones, and the like.

DESCRIPTION OF SYMBOLS 1 Adhesive 10 Joined article 11 Translucent member (1st member)
12 Back member (second member)
Reference Signs List 20 Winding member 21 Heating member 21a Nozzle 21b Discharge hole 29 Conveying screw 31 First belt (first endless member)
32 Second belt (second endless member)

Claims (8)

In a method for applying an adhesive which applies an adhesive which is softened or melted by heating to a predetermined temperature or more to a joint surface of a member,
A molding step of elongating the pressure-sensitive adhesive,
An anti-adhesion treatment step of performing an anti-adhesion treatment on the surface of the elongated pressure-sensitive adhesive molded in the molding step,
A storage step of storing the adhesive subjected to the anti-adhesion treatment in the anti-adhesion processing step until use,
The pressure-sensitive adhesive stored in the storage step is supplied to a heating member having a discharge hole and heated inside or near the discharge hole, and is softened or melted and discharged from the discharge hole, thereby joining the members. A coating step of coating the surface with a pressure-sensitive adhesive. The method for applying a pressure-sensitive adhesive according to claim 1,
In the storage step, a method for applying an adhesive, wherein the elongated adhesive is wound around a winding member. The method for applying an adhesive according to claim 1 or 2,
In the molding step, the pressure-sensitive adhesive is molded so that the diameter is 0.5 mm or more and 5.0 mm or less,
In the application step, the adhesive is heated to a temperature of 140 ° C. or more and 300 ° C. or less, and a heating and holding time of the adhesive is set to 1 second or more and 10 seconds or less. The method for applying a pressure-sensitive adhesive according to any one of claims 1 to 3,
The width of the adhesive applied to the joint surface of the member in the application step is set to 0.2 mm or more and 1.0 mm or less, and the height of the adhesive based on the joint surface is set to 50 μm or more and 500 μm or less. A method for applying a pressure-sensitive adhesive. The method for applying a pressure-sensitive adhesive according to any one of claims 1 to 4,
A method for applying a pressure-sensitive adhesive, wherein at least a thermoplastic elastomer or unvulcanized rubber and a tackifier are mixed to obtain a pressure-sensitive adhesive. The method for applying a pressure-sensitive adhesive according to any one of claims 1 to 5,
In the above anti-adhesion treatment step, an anti-adhesive agent obtained by mixing any one or more selected from the group consisting of metal soap, flaky clay mineral, and inorganic fine particles is attached to the adhesive. Application method. The method for applying a pressure-sensitive adhesive according to any one of claims 1 to 6,
In the applying step, the adhesive is fed to the heating member by a conveying screw. The method for applying a pressure-sensitive adhesive according to any one of claims 1 to 6,
In the coating step, an adhesive is disposed between the first endless member and the second endless member that are circulated and driven so as to pass through a predetermined path, and the first endless member and the second endless member are disposed. A method for applying an adhesive, wherein the adhesive is fed to the heating member by circulating.

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