Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater
  • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible
  • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
  • H05B3/286—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material the insulating material being an organic material, e.g. plastic
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/02—Details
  • H05B3/06—Heater elements structurally combined with coupling elements or holders
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
  • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
  • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
  • H05B3/145—Carbon only, e.g. carbon black, graphite
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/40—Heating elements having the shape of rods or tubes
  • H05B3/42—Heating elements having the shape of rods or tubes non-flexible
  • H05B3/48—Heating elements having the shape of rods or tubes non-flexible heating conductor embedded in insulating material

Definitions

• the present invention relates to a laminate.
• Patent Literature 1 discloses, as a wiring sheet usable for a planar heater, a wiring sheet including a pseudo-sheet structure including a plurality of electrically conductive linear bodies arranged with a spacing, a cured substance layer supporting the pseudo-sheet structure, and a pair of electrodes that are in direct contact with the electrically conductive linear bodies.
• the cured substance layer includes a cured substance of a curable adhesive and a storage modulus at 23 degrees C of the cured substance layer is in a range from 5.0 ⁇ 10 6 Pa to 1.0 ⁇ 10 10 Pa.
• Patent Literature 1 International Publication No. WO 2021/225142
• the wiring sheet described in Patent Literature 1 makes it possible to stabilize a resistance value of the wiring. However, it has been found that in a case where the wiring sheet described in Patent Literature 1 is placed in use between two base materials having different coefficients of linear expansion, one of the base materials may be cracked.
• An object of the invention is to provide a laminate capable of preventing occurrence of a crack in a base material.
• a laminate 100 according to the exemplary embodiment includes a first base material 1, a second base material 2 having a higher linear coefficient of thermal expansion than the first base material 1, and a wiring sheet 10 held between the first base material 1 and the second base material 2, as illustrated in Fig. 1 and Fig. 2 .
• the wiring sheet 10 includes a wiring body 3 including a plurality of electrically conductive linear bodies 31 arranged with a spacing, a first resin layer 4 directly or indirectly supporting the wiring body 3, and a pair of electrodes 5 being in direct contact with the electrically conductive linear bodies 31.
• first base material 1 or the second base material 2 is laminated on the wiring sheet 10 via a second resin layer 6 having a lower storage modulus than the first resin layer 4. It should be noted that in Fig. 2 , the second base material 2 and the wiring sheet 10 are laminated with the second resin layer 6 interposed therebetween.
• two holes are made in the second base material 2.
• the two holes enable electrical connection between the pair of electrodes 5 and a power source (not illustrated).
• the inventors speculate that the following is a reason why the laminate 100 according to the exemplary embodiment makes it possible to prevent occurrence of a crack in the base material.
• one reason for the occurrence of a crack in the second base material 2 is a difference in linear coefficient of thermal expansion between the first base material 1 and the second base material 2.
• the second base material 2 expands more than the first base material 1.
• the first base material 1 and the second base material 2 are fixed by the wiring sheet 10 held therebetween, the second base material 2 is warped to be cracked.
• the first base material 1 or the second base material 2 is laminated on the wiring sheet 10 via the second resin layer 6 having a lower storage modulus than the first resin layer 4.
• the second resin layer 6 is easily deformable due to a lower storage modulus.
• the second resin layer 6 deforms, which makes it possible to reduce warp to be generated in the second base material 2. Therefore, it is possible to prevent the occurrence of a crack in the base material.
• the first base material 1 is able to directly or indirectly support the wiring body 3.
• the first base material 1 is also able to protect one surface of the wiring sheet 10.
• the linear coefficient of thermal expansion of the first base material 1 is lower than the linear coefficient of thermal expansion of the second base material 2. Therefore, the exemplary embodiment makes it possible to prevent the occurrence of a crack in the second base material 2 even though the coefficients of linear expansion differ.
• the linear coefficient of thermal expansion of the first base material 1 may be 0.01 ⁇ 10 -6 /degrees C or more, 0.1 ⁇ 10 -6 /degrees C or more, or 0.5 ⁇ 10 -6 /degrees C or more.
• the linear coefficient of thermal expansion of the first base material 1 is also preferably 20 ⁇ 10 -6 /degrees C or less, more preferably 10 ⁇ 10 -6 /degrees C or less, and still more preferably 5 ⁇ 10 -6 /degrees C or less. It should be noted that the linear coefficient of thermal expansion is measurable by a method described in Examples described below. Conditions for measuring the linear coefficient of thermal expansion are as described later.
• a material of the first base material 1 is preferably resin, glass, and the like in terms of the strength and handleability of the laminate.
• a thickness of the first base material 1 is not particularly limited.
• the thickness of the first base material 1 is preferably 10 ⁇ m or more, more preferably 15 ⁇ m or more, and still more preferably 50 ⁇ m or more.
• the thickness of the first base material 1 is also preferably 10 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less.
• the second base material 2 is able to directly or indirectly support the wiring body 3.
• the second base material 2 is also able to protect one surface of the wiring sheet 10.
• the linear coefficient of thermal expansion of the second base material 2 is higher than the linear coefficient of thermal expansion of the second base material 1. Therefore, the exemplary embodiment makes it possible to prevent the occurrence of a crack in the second base material 2 even though the coefficients of linear expansion differ.
• the linear coefficient of thermal expansion of the second base material 2 is preferably 30 ⁇ 10 -6 /degrees C or more, more preferably 45 ⁇ 10 -6 /degrees C or more, and still more preferably 60 ⁇ 10 -6 /degrees C or more.
• the linear coefficient of thermal expansion of the second base material 2 is preferably 200 ⁇ 10 -6 /degrees C or less, more preferably 150 ⁇ 10 -6 /degrees C or less, and still more preferably 100 ⁇ 10 -6 /degrees C or less. It should be noted that a method of measuring the linear coefficient of thermal expansion is as described later.
• a material of the second base material 2 is preferably resin or the like in terms of the handleability and manufacturing suitability of the laminate.
• the resin examples include polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, polystyrene, polycarbonate, cycloolefin polymer, and polyimide.
• a thickness of the second base material 2 is not particularly limited.
• the thickness of the second base material 2 is preferably 10 ⁇ m or more, more preferably 30 ⁇ m or more, and still more preferably 50 ⁇ m or more.
• the thickness of the second base material 2 is also preferably 10 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less.
• the wiring sheet 10 includes the wiring body 3, the first resin layer 4, and the pair of electrodes 5.
• the wiring sheet 10 is held between the first base material 1 and the second base material 2 and both surfaces of the wiring sheet 10 are protected by the first base material 1 and the second base material 2.
• the wiring body 3 has a structure in which the plurality of electrically conductive linear bodies 31 are arranged with a spacing therebetween. Moreover, the wiring body 3 has a structure in which the plurality of electrically conductive linear bodies 31 are arranged in parallel.
• the electrically conductive linear bodies 31 may each be in a linear shape or a wavy shape in a plan view of the laminate 100. Examples of the wavy shape include sine wave, rectangular wave, triangular wave, and saw-tooth wave.
• the wiring body 3 having, for instance, such a structure can suppress breakage of the electrically conductive linear bodies 31 when the laminate 100 is stretched in an axial direction of the electrically conductive linear bodies 31.
• a volume resistivity of the electrically conductive linear bodies 31 is preferably 1.0 ⁇ 10 -9 ⁇ •m or more, more preferably 3.0 ⁇ 10 -9 ⁇ •m or more, and still more preferably 1.0 ⁇ 10 -8 ⁇ •m or more.
• the volume resistivity of the electrically conductive linear bodies 31 is also preferably 1.0 ⁇ 10 -3 ⁇ •m or less, more preferably 1.0 ⁇ 10 -4 ⁇ •m or less, and still more preferably 1.0 ⁇ 10 -5 ⁇ •m or less. At the volume resistivity of the electrically conductive linear bodies 31 within the above range, a surface resistance of the wiring body 3 is likely to decrease.
• the volume resistivity of the electrically conductive linear bodies 31 is measured as follows. Silver paste is applied to end portions of the electrically conductive linear body 31 and to portions located 40 mm from the end portions, and the resistance of the end portions and the portions located 40 mm from the end portions is measured. Then, the cross-sectional area (unit: m 2 ) of the electrically conductive linear bodies 31 is multiplied by the above resistance value, and the obtained value is divided by the above measured length (0.04 m), thereby calculating the volume resistivity of the electrically conductive linear bodies 31.
• a shape of a cross section of the electrically conductive linear bodies 31 is not particularly limited and may be a polygonal shape, a flat shape, an elliptical shape, or a circular shape.
• the shape of the cross section of the electrically conductive linear bodies 31 is preferably an elliptical shape or a circular shape in terms of affinity with the first resin layer 4, or the like.
• a diameter D of each of the electrically conductive linear bodies 31 is preferably in a range from 3 ⁇ m to 200 ⁇ m.
• the diameter D of each of the electrically conductive linear bodies 31 is more preferably 4 ⁇ m or more, still more preferably 5 ⁇ m or more.
• the diameter D of each of the electrically conductive linear bodies 31 is more preferably 150 ⁇ m or less, still more preferably 100 ⁇ m or less, still further more preferably 50 ⁇ m or less, and yet still further more preferably 20 ⁇ m or less.
• the major axis is preferably in a range similar to the above range of the diameter D.
• the diameter D of the electrically conductive linear bodies 31 is defined as an average value obtained by observing the electrically conductive linear bodies 31 with a digital microscope, measuring the diameter of the electrically conductive linear bodies 31 at five randomly selected locations, and averaging the measured values.
• a spacing L between the electrically conductive linear bodies 31 is preferably 0.3 mm or more, more preferably 0.5 mm or more, still more preferably 0.8 mm or more, and still further more preferably 1.5 mm or more.
• the spacing L between the electrically conductive linear bodies 31 is preferably 50 mm or less, more preferably 30 mm or less, still more preferably 20 mm or less, and still further more preferably 5 mm or less.
• the electrically conductive linear bodies 31 With the spacing between the electrically conductive linear bodies 31 falling within the above range, the electrically conductive linear bodies are sufficiently densely arranged, which makes it possible to improve a function of the laminate 100, such as maintaining a low resistance of the wiring body 3.
• the electrically conductive linear bodies 31 of the wiring body 3 are observed using a digital microscope and a spacing between adjacent two of the electrically conductive linear bodies 31 is measured.
• the spacing between adjacent two of the electrically conductive linear bodies 31 refers to a length along a direction in which the electrically conductive linear bodies 31 are arranged and also a length between facing portions of the two electrically conductive linear bodies 31 (see Fig. 2 ).
• the spacing L is an average value of the spacings between all the adjacent electrically conductive linear bodies 31.
• the electrically conductive linear bodies 31, may be produced by a technique such as etching, screen printing, or inkjet printing.
• the electrically conductive linear bodies 31 are suitably linear bodies each including a metal wire (hereinafter, also referred to as "metal wire linear bodies").
• the metal wire has high thermal conductivity, high electrical conductivity, and high handleability.
• the metal wire linear bodies can have significantly reduced resistance, so that an electric current necessary for the laminate 100 to generate heat can flow therethrough even when the diameter of the metal wire linear bodies is extremely reduced. This makes it possible to make the electrically conductive linear bodies 31 less visible.
• using the metal wire linear bodies as the electrically conductive linear bodies 31 reduces a resistance value of the wiring body 3 and facilitates an improvement in light transmissivity. Rapid heat generation is readily achieved in the laminate 100. Further, linear bodies with a small diameter are easy to obtain as described above.
• examples of the electrically conductive linear bodies 31 include, in addition to the metal wire linear bodies, linear bodies each including a carbon nanotube and linear bodies each including a yarn provided with electrically conductive coating.
• the metal wire linear bodies may each be a linear body including a single metal wire, or may be a linear body including a plurality of metal wires twisted together.
• the metal wire examples include wires containing metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more of metals (e.g., steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron-nickel, Nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten).
• the metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, solder, or the like or may be surface-coated with a later-described carbon material, polymer, or the like.
• Examples of the metal wire also include a metal wire coated with a carbon material.
• the metal wire is coated with a carbon material, the metallic luster is reduced, thereby making it easy to render the presence of the metal wire inconspicuous.
• coating the metal wire with the carbon material also inhibits metal corrosion.
• Examples of the carbon material for coating the metal wire include: amorphous carbons such as carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber; graphite; fullerene; graphene; and carbon nanotube.
• amorphous carbons such as carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber
• graphite fullerene
• graphene and carbon nanotube.
• the electrically conductive linear bodies 31 may be linear bodies each including a yarn provided with electrically conductive coating.
• the yarn include a yarn spun from a resin such as nylon or polyester.
• the yarn also include yarns of metal fiber, carbon fiber, and ion-conductive polymer fiber.
• the electrically conductive coating include coating films of metal, electrically conductive polymer, and carbon material.
• the electrically conductive coating may be formed by plating, deposition method, or the like.
• the linear bodies including a yarn having the electrically conductive coating enable the yarn to maintain flexibility and enable the linear bodies to improve electrical conductivity. That is to say, a reduction in the resistance of the wiring body 3 is facilitated.
• the first resin layer 4 directly or indirectly supports the wiring body 3.
• the first resin layer 4 also enables stabilization of the resistance value of the wiring body 3. That is, the first resin layer 4 can fix the conductive linear bodies 31, stabilize the contact between the conductive linear bodies 31 and the electrode 5, and make it less likely for an increase in resistance value to occur.
• a storage modulus at 23 degrees C of the first resin layer 4 is preferably in a range from 5.0 ⁇ 10 6 Pa to 1.0 ⁇ 10 10 Pa. From the same point of view, the storage modulus at 23 degrees C of the first resin layer 4 is more preferably 5.0 ⁇ 10 7 Pa or more, still more preferably 5.0 ⁇ 10 8 Pa or more. The storage modulus at 23 degrees C of the first resin layer is more preferably 7.0 ⁇ 10 9 Pa or less, still more preferably 4.0 ⁇ 10 9 Pa or less.
• a storage modulus at 105 degrees C of the first resin layer 4 is preferably 5.0 ⁇ 10 7 Pa or more, more preferably 5.0 ⁇ 10 8 Pa or more.
• the storage modulus at 105 degrees C of the first resin layer 4 is preferably 7.0 ⁇ 10 9 Pa or less, more preferably 4.0 ⁇ 10 9 Pa or less.
• the storage modulus is measurable by a method described in Examples described later.
• a thickness of the first resin layer 4 is not particularly limited.
• the thickness of the first resin layer 4 may be equal to or more than the diameter D of the electrically conductive linear bodies 31 or may be less than the diameter D of the electrically conductive linear bodies 31.
• the first resin layer 4 can contain the wiring bodies 3.
• the wiring body 3 is exposed from the first resin layer 4.
• the wiring body 3 may be exposed on a side facing the first base material 1 or exposed on a side facing the second base material 2.
• the thickness of the first resin layer 4 is preferably 1 ⁇ m or more, more preferably 5 ⁇ m or more, and still more preferably 10 ⁇ m or more.
• the thickness of the first resin layer 4 is preferably 100 ⁇ m or less, more preferably 50 ⁇ m or less, and still more preferably 30 ⁇ m or less.
• the first resin layer 4 is a layer formed of a cured product of a curable adhesive.
• curable adhesive examples include a thermosetting adhesive that cures by heat and an energy-ray-curable adhesive.
• energy ray examples include ultraviolet rays, visible rays, infrared rays, and electron beams. It should be noted that the term "energy-ray curing” also encompasses thermal curing by heating with energy rays.
• the curable adhesive include a thermosetting resin.
• the thermosetting resin is not particularly limited and specific examples thereof include an epoxy resin, a phenolic resin, a melamine resin, a urea resin, a polyester resin, a urethane resin, an acrylic resin, a benzoxazine resin, a phenoxy resin, an amine compound, and an acid anhydride compound.
• One of the above substances may be used alone or two or more of the above may be used in combination.
• an epoxy resin, a phenolic resin, a melamine resin, a urea resin, an amine compound, and an acid anhydride compound are preferably usable.
• an epoxy resin in terms of exhibiting excellent curing properties, an epoxy resin, a phenolic resin, a mixture thereof, or a mixture of an epoxy resin and at least one selected from the group consisting of a phenolic resin, a melamine resin, a urea resin, an amine compound, and an acid anhydride compound is preferably usable, and an epoxy resin is preferably usable.
• the epoxy resin is preferably a cyclic epoxy resin such as an aromatic epoxy resin or an alicyclic epoxy resin in terms of increasing the storage modulus of the first resin layer 4.
• An epoxy resin with a flexible segment such as an oxyalkylene chain tends to lower the storage modulus of the first resin layer 4.
• the energy-ray-curable adhesive contain an energy-ray-curable resin.
• the energy-ray-curable resin include a compound having at least one polymerizable double bond in a molecule, and an acrylate compound having a (meth)acryloyl group is preferable.
• acrylate compound examples include: chain-aliphatic-skeleton-containing (meth)acrylate such as dicyclopentadiene acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; cyclic-aliphatic-skeleton-containing (meth)acrylate such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylate such as polyethylene glycol di(meth)acrylate; and oligoester (
• the weight average molecular weight (Mw) of the energy-ray-curable resin is preferably 100 or more, more preferably 300 or more.
• the weight average molecular weight is also preferably 30,000 or less, more preferably 10,000 or less. It should be noted that the weight-average molecular weight as referred to herein is a value in terms of standard polystyrene, as measured by gel permeation chromatography (GPC).
• the adhesive may contain one energy-ray-curable resin or two or more energy-ray-curable resins.
• the adhesive may contain one energy-ray-curable resin or two or more energy-ray-curable resins.
• For the two or more energy-ray-curable resins a combination and ratio thereof may be selected as desired.
• a photopolymerization initiator When the energy-ray-curable resin or the thermosetting resin is used, a photopolymerization initiator, a thermal polymerization initiator, and the like are preferably used.
• a photopolymerization initiator and a thermal polymerization initiator and the like By using a photopolymerization initiator and a thermal polymerization initiator and the like, the polymerization reaction of the curable resin can be easily initiated, and the curing reaction can be readily controlled.
• photopolymerization initiator examples include photo-radical polymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, 2-chloroanthraquinone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide.
• photo-radical polymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, te
• the examples of the photopolymerization initiator also include a photo-cationic polymerization initiator in addition to the photo-radical polymerization initiator.
• a photo-cationic polymerization initiator is a compound which, upon irradiation with an energy beam, generates a cationic species to initiate the curing reaction of a cationically curable compound, and which includes a cationic moiety that absorbs the energy ray and an anionic moiety that serves as a source of acid.
• Examples of the photo-cationic polymerization initiator include a sulfonium salt compound, a iodonium salt compound, a phosphonium salt compound, an ammonium salt compound, an antimony acid salt compound, a diazonium salt compound, a selenium salt compound, an oxonium salt compound, and a bromine salt compound.
• a sulfonium salt compound is preferable and an aromatic sulfonium salt compound having an aromatic group is more preferable.
• sulfonium salt compound examples include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium tetrakis(pentafluorophenyl)borate.
• Examples of the iodonium salt compound include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, and (tricumyl)iodonium tetrakis(pentafluorophenyl)borate.
• Examples of the phosphonium salt compound include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.
• ammonium salt compound examples include benzyltrimethylammonium chloride, phenyltributylammonium chloride, and benzyltrimethylammonium bromide.
• antimony acid salt compound examples include triphenylsulfonium hexafluoroantimonate, p-(phenylthio)phenyl diphenylsulfonium hexafluoroantimonate, and diallyliodonium hexafluoroantimonate.
• thermal polymerization initiator examples include thermal radical polymerization initiators such as: hydrogen peroxides; peroxodisulfates such as ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; azo compounds such as 2,2'-azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutyronitrile, and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); and organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide.
• thermal radical polymerization initiators such as: hydrogen peroxides; peroxodisulfates such as ammonium peroxodisulfate
• the examples of the thermal polymerization initiators also include a thermal cationic polymerization initiator in addition to the above thermal radical polymerization initiator.
• the thermal cationic polymerization initiator is a compound capable of generating a cationic species that initiates polymerization upon heating.
• Examples of the thermal cationic polymerization initiator include a sulfonium salt, a quaternary ammonium salt, a phosphonium salt, a diazonium salt, and a iodonium salt. Among these, sulfonium salts are preferred from the viewpoint of easy availability and the likelihood of obtaining products excellent in adhesion and transparency.
• sulfonium salt examples include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium hexafluoroarsenate.
• Examples of the quaternary ammonium salt include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and tetrabutylammonium hydrogensulfate.
• Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate, and tetrabutylphosphonium hexafluoroantimonate.
• Examples of the diazonium salt include benzenediazonium chloride.
• Examples of the iodonium salt include diphenyliodonium hexafluoroarsenate, bis(4-chlorophenyl)iodonium hexafluoroarsenate, and phenyl(4-methoxyphenyl)iodonium hexafluoroarsenate.
• One of the above polymerization initiators may be used alone or two or more of the above may be used in combination.
• the amount thereof is preferably in a range from 0.1 parts by mass to 30 parts by mass per 100 parts by mass of the energy-ray curable resin or thermosetting resin, more preferably in a range from 0.5 parts by mass to 20 parts by mass, and still more preferably in a range from 1 part by mass to 10 parts by mass.
• thermosetting resin when used, a curing catalyst such as an imidazole curing catalyst may be used.
• the curable adhesive may contain a flexibility-adjusting component, together with an energy-ray curable resin or a thermosetting resin, in order to facilitate maintenance of the sheet shape prior to curing.
• a polymer usable as the flexibility-adjusting component include a phenoxy resin, a polyolefin resin or a modified form thereof, a polyamideimide resin, a polyimide resin, a rubber resin, and an acrylic resin.
• One of the above flexibility-adjusting components may be used alone or two or more of the above may be used in combination.
• the total amount of the energy-ray curable resin and the thermosetting resin contained in the adhesive is preferably in a range from 15 parts by mass to 300 parts by mass, more preferably in a range from 30 parts by mass to 250 parts by mass, and still more preferably in a range from 60 parts by mass to 200 parts by mass, relative to 100 parts by mass of the flexibility-adjusting component, from the viewpoint of adjusting the storage modulus of the first resin layer 4 within the above-mentioned range.
• the adhesive contains the energy-ray-curable resin or the thermosetting resin but no flexibility adjusting component, the storage modulus of the first resin layer 4 tends to become excessively high.
• the curable adhesive contain no filler.
• the adhesive contains no filler, it is possible to prevent the storage modulus at 23 degrees C of the first resin layer 4 from becoming excessively high.
• the curable adhesive may contain a filler, insofar as the storage modulus of the first resin layer 4 at 23 degrees C can be adjusted within the above-mentioned range.
• the filler examples include: inorganic powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride; spherical beads obtained by spheronizing inorganic powders; single-crystal fibers; and glass fibers.
• inorganic powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride
• spherical beads obtained by spheronizing inorganic powders single-crystal fibers
• glass fibers glass fibers.
• a silica filler and an alumina filler are preferable.
• One of the fillers may be used alone or two or more of the above may be used in combination.
• the curable adhesive may contain another component.
• the other component include known additives such as organic solvents, coupling agents, flame retardants, tackifiers, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, plasticizers, defoaming agents, and wettability modifiers.
• the electrodes 5 are used to supply current to the electrically conductive linear bodies 31.
• the electrodes 5 form a pair.
• the electrodes 5 are in direct contact with the electrically conductive linear bodies 31.
• the electrodes 5 are arranged to be electrically connected to opposite ends of the electrically conductive linear bodies 31.
• the electrode 5 can be formed using known electrode materials.
• the electrode material include an electrically conductive paste such as silver paste, a metal foil such as copper foil, and a metal wire.
• the electrode material is a metal wire, it may include a single metal wire but preferably includes two or more metal wires.
• the metal foil or the metal wire include metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold or alloys containing two or more metals, such as steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron nickel, Nichrome, nickel titanium, Kanthal, Hastelloy, and rhenium tungsten.
• the metal foil or the metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, solder, or the like.
• a width of at least one of the electrodes 5 is preferably 10 mm or less in a plan view of the laminate 100, more preferably 3 mm or less.
• the width of the electrode is also preferably 0.1 mm or more, more preferably 0.5 mm or more. It should be noted that, when at least one of the electrodes is a metal wire, the width of the electrode is the diameter of the metal wire, and when two or more metal wires are used, the width of one electrode refers to the sum of the diameters of the respective metal wires.
• a thickness of the electrodes 5 is preferably 2 ⁇ m or more, more preferably 5 ⁇ m or more, and still more preferably 10 ⁇ m or more.
• the thickness of the electrodes 5 is preferably 200 ⁇ m or less, more preferably 100 ⁇ m or less, still more preferably 50 ⁇ m or less, and still further more preferably 25 ⁇ m or less. As long as the thickness of the electrode 5 is within the above-mentioned range, high electrical conductivity and low resistance can be achieved, thereby keeping the resistance value with the pseudo-sheet structure low. Moreover, a sufficient strength as an electrode is obtainable. It should be noted that the electrodes are each provided by the metal wire, the thickness of the electrode refers to the diameter of the metal wire.
• the second resin layer 6 is provided between the first base material 1 or the second base material 2 and the wiring sheet 10.
• the second resin layer 6 has a lower storage modulus than the first resin layer 4.
• the second resin layer 6 makes it possible to prevent the occurrence of a crack in the second base material 2.
• the second base material 2 and the wiring sheet 10 are laminated with the second resin layer 6 interposed therebetween.
• a storage modulus at 23 degrees C of the second resin layer 6 is preferably in a range from 1.0 ⁇ 10 4 Pa to 3.0 ⁇ 10 5 Pa. From the same point of view, the storage modulus at 23 degrees C of the second resin layer 6 is more preferably 4.0 ⁇ 10 4 Pa or more, still more preferably 8.0 ⁇ 10 4 Pa or more. The storage modulus at 23 degrees C of the second resin layer 6 is more preferably 2.5 ⁇ 10 5 Pa or less, still more preferably 2.0 ⁇ 10 5 Pa or less.
• a storage modulus at 105 degrees C of the second resin layer 6 is preferably 5.0 ⁇ 10 3 Pa or more, more preferably 5.0 ⁇ 10 4 Pa or more.
• the storage modulus at 105 degrees C of the second resin layer 6 is preferably 4.0 ⁇ 10 4 Pa or less, more preferably 3.0 ⁇ 10 4 Pa or less.
• the storage modulus is measurable by a method described in Examples described later.
• a thickness of the second resin layer 6 is not particularly limited.
• the thickness of the second resin layer 6 is preferably 1 ⁇ m or more, more preferably 5 ⁇ m or more, and still more preferably 10 ⁇ m or more.
• the thickness of the second resin layer 6 is preferably 1,000 ⁇ m or less, more preferably 500 ⁇ m or less, and still more preferably 300 ⁇ m or less.
• the second resin layer 6 is preferably the following pressure-sensitive adhesive layer.
• the pressure-sensitive adhesive layer can be formed of a pressure-sensitive adhesive obtained by crosslinking (heat crosslinking) a pressure-sensitive adhesive composition (hereinafter sometimes referred to as "pressure-sensitive adhesive composition P") containing, for example, a (meth)acrylic acid ester polymer (A) and a crosslinking agent (B), or an energy-ray-curable component (C), or both thereof.
• pressure-sensitive adhesive composition P preferably further contains a photopolymerization initiator (D) as desired.
• (meth)acrylic acid herein means both an acrylic acid and a methacrylic acid. The same applies to other similar terms.
• the term “polymer” herein shall be understood to also encompass “copolymer,” unless otherwise specified.
• the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition at the stage of the pressure-sensitive adhesive sheet, that is, prior to being applied to an adherend, has not yet been cured by an energy ray and exhibits a relatively low storage modulus.
• the stress generated upon lamination to an adherend can be mitigated.
• the pressure-sensitive adhesive layer readily follows the irregularities, whereby the occurrence of gaps, lifting, or the like in the vicinity of the irregularities is suppressed, and excellent lamination property to the adherend is exhibited.
• the (meth)acrylic acid ester polymer (A) contains, as monomer units constituting the polymer, an alkyl (meth)acrylate and a monomer having a reactive functional group in a molecule (a reactive-functional-group-containing monomer).
• the (meth)acrylic acid ester polymer (A) can exhibit desirable pressure-sensitive adhesion by containing, as monomer units constituting the polymer, an alkyl (meth)acrylate.
• an alkyl (meth)acrylate an alkyl (meth)acrylate having an alkyl group with 1 to 20 carbon atoms is preferable.
• the alkyl group may be linear or branched and may have a cyclic structure.
• alkyl (meth)acrylates having an alkyl group with 1 to 20 carbon atoms include (meth)acrylic acid methyl, (meth)acrylic acid ethyl, (meth)acrylic acid propyl, (meth)acrylic acid n-butyl, (meth)acrylic acid n-pentyl, (meth)acrylic acid n-hexyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid n-decyl, (meth)acrylic acid n-dodecyl, (meth)acrylic acid myristyl, (meth)acrylic acid palmityl, (meth)acrylic acid stearyl, (meth)acrylic acid cyclohexyl, (meth)acrylic acid isobornyl, and (meth)acrylic acid adamantyl.
• One of the above may be used
• an alkyl (meth)acrylate having an alkyl group having 4 to 20 carbon atoms is preferable as the alkyl (meth)acrylate.
• the alkyl (meth)acrylates having an alkyl group having 4 to 20 carbon atoms (meth)acrylic acid n-butyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid isobornyl and the like are preferable.
• (meth)acrylic acid n-butyl, (meth)acrylic acid 2-ethylhexyl, and (meth)acrylic acid isobornyl are more preferable, and acrylic acid n-butyl, acrylic acid 2-ethylhexyl, acrylic acid isobornyl and the like are particularly preferable.
• the (meth)acrylic acid ester polymer (A) preferably contains 40 mass% or more of an alkyl (meth)acrylate as monomer units constituting the polymer, more preferably 50 mass% or more, still more preferably 60 mass% or more, and particularly preferably 70 mass% or more.
• the polymer can exhibit favorable pressure-sensitive adhesion.
• the (meth)acrylic acid ester polymer (A) preferably contains 99 mass% or less of an alkyl (meth)acrylate as monomer units constituting the polymer, more preferably 95 mass% or less, and still more preferably 90 mass% or less.
• the (meth)acrylic acid ester polymer (A) When the content of the alkyl (meth)acrylate is 99 mass% or less, another monomer component can be suitably introduced into the (meth)acrylic acid ester polymer (A).
• the (meth)acrylic acid ester polymer (A) when the (meth)acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer constituting the polymer, the (meth)acrylic acid ester polymer (A) preferably contains 87 mass% or less of an alkyl (meth)acrylate as monomer units constituting the polymer, and more preferably 83 mass% or less.
• the (meth)acrylic acid ester polymer (A) contains a reactive functional group-containing monomer as monomer units constituting the polymer, whereby the polymer reacts with the crosslinking agent (B) described later through the reactive functional group derived from the reactive functional group-containing monomer, thereby forming a crosslinked structure (three-dimensional network structure), and consequently a pressure-sensitive adhesive having the desired cohesive force is obtained.
• reactive functional group-containing monomers contained as monomer units in the (meth)acrylic acid ester polymer (A) preferred examples include monomers having a hydroxyl group in a molecule (hydroxyl group-containing monomers), monomers having a carboxyl group in a molecule (carboxyl group-containing monomers), and monomers having an amino group in a molecule (amino group-containing monomers).
• One of the reactive functional group-containing monomers may be used alone, or two or more thereof may be used in combination.
• hydroxyl group-containing monomers or carboxyl group-containing monomers are preferable from the viewpoint of facilitating adjustment of the crosslinking density and easily obtaining a pressure-sensitive adhesive having the desired cohesive force. From the viewpoint of pressure-sensitive adhesion and resistance to moisture-heat whitening, hydroxyl group-containing monomers are preferable.
• hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.
• hydroxyalkyl (meth)acrylates having a hydroxyalkyl group having 1 to 4 carbon atoms are preferable.
• preferred examples include 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate, and particularly 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferable.
• One of the above may be used alone, or two or more thereof may be used in combination.
• carboxyl group-containing monomers examples include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid.
• acrylic acid is preferable from the viewpoint of the cohesive force of the resulting (meth)acrylic acid ester polymer (A).
• One of the above may be used alone, or two or more thereof may be used in combination.
• the (meth)acrylic acid ester polymer (A) preferably contains 1 mass% or more of the reactive functional group-containing monomer as monomer units constituting the polymer, more preferably 3 mass% or more, and still more preferably 5 mass% or more.
• the reactive functional group-containing monomer is a hydroxyl group-containing monomer
• the (meth)acrylic acid ester polymer (A) preferably contains 5 mass% or more thereof, more preferably 8 mass% or more, and still more preferably 10 mass% or more.
• the content is preferably less than 25 mass%, more preferably 20 mass% or less, and still more preferably 16 mass% or less.
• the (meth)acrylic acid ester polymer (A) preferably contains 50 mass% or less of the reactive functional group-containing monomer as monomer units constituting the polymer, more preferably 40 mass% or less, and still more preferably 30 mass% or less.
• the (meth)acrylic acid ester polymer (A) contains, as monomer units constituting the polymer, a nitrogen-atom-containing monomer.
• a nitrogen atom-containing monomer as a constitutional unit into the polymer, a predetermined polarity can be imparted to the pressure-sensitive adhesive, thereby allowing the pressure-sensitive adhesive to exhibit excellent affinity even for an adherend having a certain degree of polarity, such as glass.
• the nitrogen atom-containing monomer include, in addition to the aforementioned amino group-containing monomer as the reactive functional group-containing monomer, a monomer having an amide group and a monomer having a nitrogen-containing heterocycle.
• a monomer having a nitrogen-containing heterocycle is preferable in terms of imparting an appropriate rigidity to the (meth)acrylic acid ester polymer (A).
• nitrogen atom-containing monomer examples include N-vinylcarboxylic acid amide, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-ethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-phenyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, and N-vinylcaprolactam.
• N-vinylcarboxylic acid amide examples include N-vinylcarboxylic acid amide, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide,
• One of the nitrogen atom-containing monomer may be used alone, or two or more thereof may be used in combination.
• Examples of the monomer having a nitrogen-containing heterocycle include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, and N-vinylphthalimide.
• N-(meth)acryloylmorpholine is preferable because of exhibiting superior pressure-sensitive adhesion, and particularly N-acryloylmorpholine (4-acryloylmorpholine) is preferable.
• the polymer when the (meth)acrylic acid ester polymer (A) contains, as monomer units constituting the polymer, a monomer having a nitrogen-containing heterocycle, the polymer preferably contains 0.5 mass% or more of a nitrogen atom-containing monomer, more preferably 1 mass% or more, and still more preferably 3 mass% or more. Further, the (meth)acrylic acid ester polymer (A) preferably contains 20 mass% or less of a monomer having a nitrogen-containing heterocycle as monomer units constituting the polymer, more preferably 15 mass% or less, and still more preferably 8 mass% or less. When the content of the monomer having a nitrogen-containing heterocycle is within the above range, the resulting pressure-sensitive adhesive can effectively exhibit excellent adhesion to adherends such as glass.
• the (meth)acrylic acid ester polymer (A) may optionally contain other monomers as monomer units constituting the polymer.
• the other monomers include (meth)acrylic acid alkoxyalkyl esters such as (meth)acrylic acid methoxyethyl and (meth)acrylic acid ethoxyethyl, vinyl acetate, and styrene.
• One of the above may be used alone, or two or more thereof may be used in combination.
• the (meth)acrylic acid ester polymer (A) is preferably a linear polymer.
• a linear polymer By being a linear polymer, entanglement of molecular chains is more likely to occur, which can be expected to improve cohesive force, thereby providing an improved pressure-sensitive adhesive.
• the polymerization mode of the (meth)acrylic acid ester polymer (A) may be a random copolymer or may be a block copolymer.
• the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, and still more preferably 400,000 or more.
• the lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is at least the above value, the second resin layer and the laminate exhibit excellent long-term durability.
• the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 2,000,000 or less, more preferably 1,500,000 or less, still more preferably 1,000,000 or less, and still further more preferably 800,000 or less.
• the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is at most the above value, at least one of the lamination property or the adhesion of the resulting pressure-sensitive adhesive to an adherend is improved.
• one of the (meth)acrylic acid ester polymer (A) may be used alone or two or more thereof may be used in combination.
• the crosslinking agent (B) can crosslink the (meth)acrylic acid ester polymer (A) by heating the pressure-sensitive adhesive composition P, thereby enabling favorable formation of a three-dimensional network structure. As a result, the cohesive force of the resulting pressure-sensitive adhesive is further improved.
• crosslinking agent (B) any compound that can react with the reactive functional group of the (meth)acrylic acid ester polymer (A) may be used.
• the crosslinking agent (B) include an isocyanate crosslinking agent, epoxy crosslinking agent, amine crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent, and ammonium salt crosslinking agent.
• the reactive functional group of the (meth)acrylic acid ester polymer (A) is a hydroxyl group
• the reactive functional group of the (meth)acrylic acid ester polymer (A) is a carboxyl group
• One of the crosslinking agent (B) may be used alone or two or more thereof may be used in combination.
• the isocyanate crosslinking agent contains at least a polyisocyanate compound.
• polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate.
• the examples include biuret derivatives and isocyanurate derivatives thereof, as well as adducts which are reaction products with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.
• adducts which are reaction products with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.
• trimethylolpropane-modified aromatic polyisocyanates are preferable, and in particular, it is preferable to use at least one of trimethylolpropane-modified tolylene diisocyanate or trimethylolpropane-modified xylylene diisocyanate.
• epoxy crosslinking agent examples include 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, and diglycidylamine.
• 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane is preferable.
• the content of the crosslinking agent (B) in the pressure-sensitive adhesive composition P is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and still more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A). Further, the content thereof is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and still more preferably 1 part by mass or less.
• the degree of crosslinking becomes appropriate, and the resulting pressure-sensitive adhesive can be more easily adjusted to a favorable value of storage modulus as described above, thereby being improved.
• the pressure-sensitive adhesive composition P when crosslinked (thermally crosslinked), provides a pressure-sensitive adhesive that is energy-ray curable. It is presumed that, by curing upon irradiation with energy rays after being applied to an adherend, the energy-ray-curable component (C) polymerizes with each other, and the polymerized energy-ray-curable component (C) entangles with the crosslinked structure (three-dimensional network structure) of the (meth)acrylic acid ester polymer (A).
• the pressure-sensitive adhesive having such a higher-order structure exhibits high cohesive force and shows high coating film strength.
• the energy-ray-curable component (C) is not particularly limited as long as it is a component that cures upon irradiation with energy rays to provide the above effects, and may be a monomer, an oligomer, or a polymer, or a mixture thereof.
• multifunctional acrylate monomers having excellent compatibility with the (meth)acrylic acid ester polymer (A) and the like can be preferably mentioned.
• multifunctional acrylate monomers include difunctional types such as tricyclodecanedimethanol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentenyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloxyethyl)isocyanurate, allyl cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, and 9,9-bis[4-(2-acryloyl)
• the multifunctional acrylate monomer preferably has a molecular weight of less than 1000.
• the content of the energy-ray-curable component (C) in the pressure-sensitive adhesive composition P is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and still further more preferably 5 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A).
• the content of the energy-ray-curable component (C) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less, and still further more preferably 7.5 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A).
• the pressure-sensitive adhesive composition P preferably further contains a photopolymerization initiator (D).
• a photopolymerization initiator (D) By containing such a photopolymerization initiator (D), the energy-ray-curable component (C) can be efficiently polymerized, and the polymerization curing time and the irradiation dose of the energy rays can be reduced.
• Examples of the photopolymerization initiator (D) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoate, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, ⁇ -chloroanthraquinone, 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, 2-benzothiazole-N,N-diethyldithiocarbamate, 2,4,6-trimethylbenzoyl diphenyl
• the content of the photopolymerization initiator (D) in the pressure-sensitive adhesive composition P is preferably 0.1 parts by mass or more, more preferably 1.0 part by mass or more, and still more preferably 5.0 parts by mass or more, relative to 100 parts by mass of the energy-ray-curable component (C). Further, the content thereof is preferably 35 parts by mass or less, more preferably 25 parts by mass or less, and still more preferably 15 part by mass or less. When the content of the photopolymerization initiator (D) is within this range, it undergoes cleavage without problems upon irradiation with energy rays, and the curability of the energy-ray-curable component (C) is further improved. Further, the above-described storage modulus is more easily satisfied.
• various additives that are commonly used in acrylic pressure-sensitive adhesives may be used in the pressure-sensitive adhesive composition P.
• the various additives include silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, plasticizers, fillers, and refractive index modifiers.
• a method for producing the laminate 100 ilm is not particularly limited.
• the laminate 100 can be produced, for example, by the following steps.
• a step of producing a wiring body film provided with a wiring body 3 is carried out.
• a thermosetting adhesive for forming the first resin layer 4 is applied onto a release film to form a coating film.
• the coating film is dried to produce an adhesive layer.
• the conductive linear body 31 is placed on the adhesive layer while being arranged, thereby forming the wiring body 3.
• the drum member is rotated while winding the conductive linear body 31 spirally around the adhesive layer. Thereafter, the bundle of the conductive linear body 31 wound spirally is cut along the axial direction of the drum member.
• the wiring body 3 is formed and disposed on the adhesive layer.
• a wiring body film in which the wiring body 3 is formed on the adhesive layer with a release film is obtained.
• this method for example, by rotating the drum member while moving the feeding portion of the conductive linear body 31 along a direction parallel to the axis of the drum member, it is easy to adjust the spacings L between the adjacent conductive linear bodies 31 in the wiring body 3.
• a step of providing a pair of electrodes 5 on the first base material 1 is carried out.
• a pair of electrodes 5 can be provided on the first base material 1, for example, by printing a conductive paste or the like in a predetermined arrangement and then drying it.
• thermosetting adhesive is subjected to a predetermined heat treatment to form the first resin layer 4, thereby forming a wiring sheet 10 on the first base material 1.
• a step of producing a protective film provided with the second base material 2 and the second resin layer 6 is carried out.
• the pressure-sensitive adhesive composition P for forming the second resin layer 6 is applied onto the second base material 2 to form a coating film, thereby producing the protective film. It is preferable, as illustrated in Figs. 1 and 2 , to provide two holes in the second base material 2.
• a step of placing the protective film on the first base material 1 provided with the wiring sheet 10 and crosslinking the pressure-sensitive adhesive composition P is carried out.
• the protective film is laminated onto the first base material 1 provided with the wiring sheet 10 such that, in a plan view, the two holes of the protective film overlap with the pair of electrodes 5, and the coating film of the pressure-sensitive adhesive composition P of the protective film comes into contact with the wiring sheet 10.
• the second resin layer 6 is formed, thereby producing the laminate 100.
• the second exemplary embodiment is different from the first exemplary embodiment in that the first base material 1 and the wiring sheet 10 are laminated with the second resin layer 6 interposed therebetween, as illustrated in a cross-sectional view of a laminate 100A.
• the laminate 100A includes the first base material 1, the second base material 2 having a higher linear coefficient of thermal expansion than the first base material 1, and the wiring sheet 10 held between the first base material 1 and the second base material 2, as illustrated in Fig. 3 .
• the wiring sheet 10 includes a wiring body 3 including a plurality of electrically conductive linear bodies 31 arranged with a spacing, the first resin layer 4 directly or indirectly supporting the wiring body 3, and a pair of electrodes 5 being in direct contact with the electrically conductive linear bodies 31.
• the first base material 1 and the wiring sheet 10 are laminated with the second resin layer 6 having a lower storage modulus than the first resin layer 4.
• the advantages (1) to (4) described in the first exemplary embodiment can be achieved.
• the invention is not limited to the above exemplary embodiments and includes any modification, improvement, and the like as long as the object of the invention can be achieved.
• the laminate 100 includes the film-shaped first base material 1, but is not limited thereto.
• the first base material 1 may be a base material formed into a three-dimensional shape.
• the wiring sheet 10 can be attached to the first base material 1, which is the adherend, by means of the first resin layer 4 or the second resin layer 6.
• the cross-sectional view of the laminate 100A is modified in that the first base material 1 and the wiring sheet 10 are laminated with the second resin layer 6 interposed therebetween; however, the modification is not limited thereto.
• two other modifications can be given.
• One modification is an example in which, in the first exemplary embodiment, the wiring sheet 10 is turned upside down such that the electrode 5 is provided on the side of the second base material 2.
• the other modification is an example in which, in the second exemplary embodiment, the wiring sheet 10 is turned upside down such that the electrode 5 is provided on the side of the second base material 2.
• a cylindrical test sample having a diameter of 8 mm and a thickness of 1 mm was prepared from the same composition as that used to form the layer to be measured.
• the storage modulus of the test sample was measured using a dynamic viscoelasticity measuring apparatus (MCR300, manufactured by Anton Paar) under the following conditions: a parallel plate with a diameter of 8 mm as the measuring fixture, a test starting temperature of -20 degrees C, a test ending temperature of 150 degrees C, a heating rate of 3 degrees C/min, a shear strain of 0.05%, and a frequency of 1 Hz.
• MCR300 dynamic viscoelasticity measuring apparatus
• a base material was cut into a rectangular shape of 4.5 mm ⁇ 20 mm to prepare a test sample.
• a linear coefficient of thermal expansion of the test sample was measured using a thermomechanical analyzer (TMA4000SE, manufactured by Netzsch Japan) under the following conditions: tensile load of 2 g, temperature range from 23 degrees C to 105 degrees C, and heating rate of 5 degrees C/min.
• a curable adhesive was obtained by blending 100 parts by mass of a phenoxy resin (YX7200B35, manufactured by Mitsubishi Chemical Corporation) with 170 parts by mass of a multifunctional hydrogenated bisphenol A diglycidyl ether epoxy compound (YX8000, manufactured by Mitsubishi Chemical Corporation), 0.2 parts by mass of a silane coupling agent (KBM-4803, manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of a thermal cationic polymerization initiator (SANEID SI-B3, manufactured by Sanshin Chemical Industry Co., Ltd.), and 2 parts by mass of a thermal cationic polymerization initiator (SANEID SI-B7, manufactured by Sanshin Chemical Industry Co., Ltd.).
• a (meth)acrylic acid ester polymer (A) was prepared by copolymerizing 65 parts by mass of 2-ethylhexyl acrylate, 5 parts by mass of 4-acryloylmorpholine, 15 parts by mass of isobornyl acrylate, and 15 parts by mass of 2-hydroxyethyl acrylate.
• the molecular weight of the (meth)acrylic acid ester polymer (A) was measured, and the weight-average molecular weight (Mw) was 500,000.
• the glass transition temperature (Tg, in degrees C) of the (meth)acrylic acid ester polymer (A) was calculated to be -36.5 degrees C according to the Fox equation, based on the glass transition temperatures (Tg) of the respective monomers constituting the (meth)acrylic acid ester polymer (A) as homopolymers.
• a coating solution of a pressure-sensitive adhesive composition was obtained by mixing 100 parts by mass (in terms of solid content; the same shall apply hereinafter) of the obtained (meth)acrylic acid ester polymer (A), 0.18 parts by mass of a crosslinking agent (B), namely trimethylolpropane-modified tolylene diisocyanate, 7 parts by mass of an energy-ray curable component (C), namely ⁇ -caprolactone-modified tris-(2-acryloyloxyethyl) isocyanurate, 0.7 parts by mass of a mixture of a photopolymerization initiator (D), namely benzophenone and 1-hydroxycyclohexyl phenyl ketone in a 1:1 mass ratio, and 0.28 parts by mass of a silane coupling agent, namely 3-glycidoxypropyltrimethoxysilane, followed by sufficient stirring and dilution with methyl ethyl ketone.
• a crosslinking agent B
• C energy-
• a coating solution of a pressure-sensitive adhesive composition was obtained by mixing 100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in Preparation Example 2, 0.15 parts by mass of a crosslinking agent (B), namely trimethylolpropane-modified tolylene diisocyanate, 5 parts by mass of an energy-ray curable component (C), namely ⁇ -caprolactone-modified tris-(2-acryloyloxyethyl) isocyanurate, 0.5 parts by mass of a photopolymerization initiator (D), namely 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 0.25 parts by mass of a silane coupling agent, namely 3-glycidoxypropyltrimethoxysilane, followed by sufficient stirring and dilution with methyl ethyl ketone.
• a crosslinking agent B
• C energy-ray curable component
• D photopolymerization initiator
• a (meth)acrylic acid ester polymer (A) was prepared by copolymerizing 30 parts by mass of 2-ethylhexyl acrylate, 25 parts by mass of n-butyl acrylate, 5 parts by mass of 4-acryloylmorpholine, 15 parts by mass of isobornyl acrylate, and 25 parts by mass of 2-hydroxyethyl acrylate.
• the molecular weight of the (meth)acrylic acid ester polymer (A) was measured, and the weight-average molecular weight (Mw) was 600,000.
• a coating solution of a pressure-sensitive adhesive composition was obtained by mixing 100 parts by mass of the obtained (meth)acrylic acid ester polymer (A), 0.2 parts by mass of a crosslinking agent (B), namely trimethylolpropane-modified tolylene diisocyanate, 8.0 parts by mass of an energy-ray curable component (C), namely ⁇ -caprolactone-modified tris-(2-acryloyloxyethyl) isocyanurate, 0.8 parts by mass of a photopolymerization initiator (D), namely 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 0.2 parts by mass of a silane coupling agent, namely 3-glycidoxypropyltrimethoxysilane, followed by sufficient stirring and dilution with methyl ethyl ketone.
• a crosslinking agent B
• C energy-ray curable component
• D photopolymerization initiator
• silane coupling agent namely 3-
• An adhesive sheet was prepared by coating a curable adhesive obtained in Preparation Example 1 onto a release film having a thickness of 38 ⁇ m (SP-382150, manufactured by Lintec Corporation) so as to have a thickness of 15 ⁇ m, and cutting the coated product into a rectangle of 250 mm ⁇ 320 mm.
• a gold-plated tungsten wire having a diameter of 10 ⁇ m was prepared (hereinafter also referred to simply as "wire").
• the obtained adhesive sheet was wound around a drum member having a rubber outer peripheral surface in such a manner that the surface of the pressure-sensitive adhesive layer faced outward and no wrinkles were formed, and both ends of the adhesive sheet in the circumferential direction were fixed with a double-sided tape.
• the wire wound on a bobbin was first attached to the surface of the pressure-sensitive adhesive layer of the adhesive sheet located near an end portion of the drum member. Then, while unwinding the wire from the bobbin, the wire was wound onto the drum member, and the drum member was gradually moved in a direction parallel to the drum axis so that the wire was helically wound around the drum member at equal intervals of 3 mm. As a result, a wiring body was formed in such a manner that 96 wires were arranged on the surface of the adhesive. Thereafter, the wire was cut, and the wiring body was removed from the drum member. The wiring body was then cut into a width of 40 ⁇ 82 mm so as to obtain 12 wires, thereby preparing a wiring body film.
• a strip-shaped electrode having a thickness of 17 ⁇ m was formed by screenprinting silver paste with a width of 2 mm and an inter-electrode distance of 7.8 mm onto a glass substrate serving as a first base material and having a thickness of 2 mm and a linear coefficient of thermal expansion of 3.3 ⁇ 10 -6 /degrees C, followed by drying at 150 degrees C for 30 minutes. Thereafter, electroless plating was applied to the strip-shaped electrode to fabricate a substrate with electrodes.
• the obtained wiring body film was laminated onto the obtained substrate with electrodes such that the electrodes were positioned at both ends of the wires. Thereafter, heating was performed at 120 degrees C and 0.5 MPa for 30 minutes to cure the adhesive, thereby forming a first resin layer and forming a wiring sheet on the first base material.
• the storage modulus of the first resin layer was 2.2 ⁇ 10 9 Pa at 23 degrees C and 1.6 ⁇ 10 9 Pa at 105 degrees C.
• a coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 2 was applied so as to have a thickness of 100 ⁇ m, and then cut into a rectangle of 50 mm ⁇ 120 mm. Thereafter, two circular holes each having a diameter of 5 mm were punched out such that the distance between the centers of the two circular holes was 7.8 mm, thereby preparing a protective sheet.
• Table 1 shows the linear coefficient of thermal expansion of the second base material.
• a protective sheet was laminated onto the first base material provided with a wiring sheet such that the electrodes of the wiring sheet were aligned with the circular holes of the protective sheet. Thereafter, ultraviolet light having a wavelength of 365 nm was irradiated under conditions of an irradiance of 200 mW/cm 2 and an exposure dose of 1000 mJ/cm 2 to form a second resin layer, thereby obtaining a laminate.
• Table 1 also shows storage moduli at 23 degrees C and 105 degrees C of the second resin layer.
• a laminate was prepared in the same manner as in Example 1 except that the cycloolefin polymer film (product name: 'ZF16', manufactured by Zeon Corporation) used as the protective sheet was replaced with a polycarbonate film (product name: 'L-100', manufactured by Teijin Limited).
• a polycarbonate film product name: 'L-100', manufactured by Teijin Limited.
• a laminate was prepared in the same manner as in Example 1 except that the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 2 was replaced with the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 3.
• a laminate was prepared in the same manner as in Example 1 except that the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 2 was replaced with the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 4.
• a laminate was prepared in the same manner as in Example 1, except that the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 2 was replaced with the coating solution of the pressure-sensitive adhesive composition obtained in Preparation Example 4, and the cycloolefin polymer film (product name: 'ZF16', manufactured by Zeon Corporation) used as the protective sheet was replaced with a polycarbonate film (product name: 'L-100', manufactured by Teijin Limited).
• Table 1 Linear Coefficient of Thermal Expansion of Second Base Material ( ⁇ 10 -6 /°C) Storage Modulus at 23°C of Second Resin Layer (MPa) Storage Modulus at 105°C of Second Resin Layer (MPa) Result of Crack Evaluation Ex.
• the laminates obtained in Examples 1 to 3 showed favorable results in the evaluation of cracks. Accordingly, it was confirmed that, according to the invention, a laminate capable of preventing the occurrence of cracks in the base material can be obtained.

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• 2024
  • 2024-03-27 EP EP24780535.1A patent/EP4694576A1/de active Pending
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