JP2009199746A - Heat-generating glass, and its manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably pass a heavy current by ensuring the junction of fillers of a resin-based conductive adhesive each other to improve reliability of conduction, in heat-generating glass formed with electrode terminals by the resin-based conductive adhesive. <P>SOLUTION: A transparent conductive film 16 is formed on the surface of a glass plate 10. Conductive adhesives 18a, 20a are applied to the facing positions on the surface of the transparent conductive film 16 and are cured to form a pair of feeding electrode terminals 18, 20. A voltage is impressed between the electrode terminals 18, 20 and the transparent conductive film 16 is energized to generate heat in the transparent conductive film 16. The conductive adhesives 18a, 20a contain an organic resin and a conductive filler. The conductive filler is composed of: a main conductive filler 26 formed by plating lead-free solder on a base material; an auxiliary filler 28 having a volume smaller than that of the main conductive filler 26 and a particle diameter of 0.1-1 μm and comprising lead-free solder balls; and a nano particle auxiliary filler 30 having a volume smaller than that of the auxiliary filler 28 with a particle diameter of 1-50 nm and comprising lead-free solder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a heat-generating glass whose electrode terminals are made of a resin-based conductive adhesive and a method for manufacturing the same. The present invention relates to a resin-based conductive adhesive filler that reliably joins fillers to improve conduction reliability and stabilize a large current. It was made to be able to flow.

The exothermic glass is formed by forming a transparent conductive film on the surface of a glass plate, and energizing the transparent conductive film to generate heat, thereby raising the temperature of the glass plate and exhibiting functions such as prevention of condensation. The exothermic glass is configured as, for example, an exothermic multi-layer glass. An example of the structure of the heat-generating multilayer glass is shown in FIG. Two glass plates 10 and 12 are arranged opposite to each other with a frame-like spacer 14 therebetween, and are integrated. A transparent conductive film 16 made of ITO (indium tin oxide), SnO ₂ (tin oxide), or the like is formed on the surface of one (usually indoor side) glass plate 10 facing the other glass plate 12. Electrode terminal pairs 18 and 20 constituting power supply terminals (a bus bar portion and a current collecting portion) are formed at opposite end positions on the surface of the transparent conductive film 16. For example, the electrode terminal pairs 18 and 20 are formed by applying paste-like conductive adhesives 18a and 20a to the opposite end positions of the surface of the transparent conductive film 16 by screen printing or the like, and then applying flat knitted copper wires 18b and 20b thereon. The conductive adhesives 18a and 20a are cured and bonded to each other. Lead wires 22 and 24 are soldered to the flat knitted copper wires 18b and 20b of the electrode terminal pairs 18 and 20, respectively. When a voltage is applied between the lead wires 22 and 24 and the transparent conductive film 16 is energized, the transparent conductive film 16 generates heat and the glass plate 10 is heated.

  The conductive adhesive will be described. As an example of a conductive adhesive, a binder made of an organic resin, a conductive filler of tin and / or a tin alloy, a powder of gold and / or silver, or an alloy thereof, or a powder plated with these metals A conductive adhesive made of a filler has been proposed (see, for example, Patent Document 1). This conductive adhesive is made by adding a thermosetting resin and heating it to 150 to 250 ° C., so that the conductive fillers in the resin come into contact with each other as the resin component contracts. .

  In addition, a conductive adhesive in which a thermoplastic resin, a metal powder, and a metal fiber are blended using lead-free solder as a main conductive material has been proposed (see, for example, Patent Document 2). Since this conductive adhesive is fused and “bonded” between the lead-free solder powders, it is more firmly connected than “contact”, and is excellent in conductivity.

  In addition, as a conductive adhesive composed of an organic resin and a conductive filler, the conductive filler, a main conductive filler obtained by plating lead-free solder on the base material, a volume smaller than the volume of the main conductive filler and the base material Proposed is composed of auxiliary filler plated with lead-free solder having a particle size of 0.1-1 μm and lead-free solder balls smaller than the volume of the main conductive filler and having a particle size of 0.1-1 μm (For example, refer to Patent Document 3). According to this conductive adhesive, the auxiliary filler and the lead-free solder ball enter between the main conductive fillers, and the lead-free solder plating of the main conductive filler becomes between the auxiliary filler and the lead-free solder ball by heating during bonding. Therefore, the resistance can be reduced and an electrically stable connection can be realized.

JP 2000-309773 A JP 2000-357413 A JP 2005-26187 A

  However, the conductive adhesive described in Patent Document 1 has no problem when a relatively small current is applied, such as when used for an electrode terminal of an automobile window glass formed with an antenna of an electronic device, AM, FM, TV, etc. When a large current of 5 A or more is applied like glass, the contact portion of the conductive filler generates heat and becomes high temperature, so that the oxidation of the surface of the conductive filler is promoted to increase the contact resistance value. Falls into a vicious circle of high temperatures. Moreover, when a conductive filler becomes high temperature, the thermosetting resin which intervenes burns and carbonizes, and adhesive capability falls. These reductions are repeated and the end is short-circuited.

  In addition, the conductive adhesive described in Patent Document 2 is 35 to 75% by weight of thermoplastic resin, and has a large weight and a large resistance value with respect to the entire conductive adhesive. Therefore, Patent Document 1 describes a current of 1 A or more. The same phenomenon as that occurs.

  In addition, although the conductive adhesive described in Patent Document 3 can flow a larger current than those described in Patent Documents 1 and 2, the filler can be more reliably joined to further improve the reliability of conduction and increase the current. It is desirable to make it flow stably.

  The present invention has been made in view of the above points. When the electrode terminal is made of a resin-based conductive adhesive, the bonding between the fillers is ensured and the reliability of conduction is improved to stably generate a large current. An object of the present invention is to provide a heat-generating glass that can be flowed and a method for producing the same.

  The exothermic glass of this invention forms a transparent conductive film on the surface of a glass plate, applies a conductive adhesive to the opposing position of the surface of the transparent conductive film, and cures to form a pair of power supply electrode terminals. In a heat generating glass that applies a voltage between terminals and energizes the transparent conductive film to generate heat, the conductive adhesive contains an organic resin and a conductive filler, and the conductive filler is A main conductive filler in which a lead-free solder is plated on a base material, an auxiliary filler made of lead-free solder balls having a volume smaller than the main conductive filler and a particle size of 0.1 to 1 μm, and the auxiliary filler. It is characterized by comprising a nanoparticle auxiliary filler made of lead-free solder having a small volume and a particle size of 1 to 50 nm.

  According to the heat generating glass of the present invention, as a conductive adhesive constituting the electrode terminal, an auxiliary filler having a particle diameter of 0.1 to 1 μm obtained by plating lead-free solder on a base material from the conductive adhesive described in Patent Document 3. Is used instead of a composition in which a nanoparticle auxiliary filler made of lead-free solder having a particle size of 1 to 50 nm is added (the auxiliary filler of the present invention is a lead-free conductive adhesive described in Patent Document 3). Compared to the conductive adhesive described in Patent Document 3, the auxiliary filler and the nanoparticle auxiliary filler are more easily inserted between the main conductive fillers, and the nanoparticle auxiliary filler is fine particles of lead-free solder. Therefore, it becomes easy to melt by heat, and it is possible to improve the reliability of conduction by reliably joining the fillers. Thereby, a large current can flow stably. In particular, according to this invention, since the auxiliary filler of Patent Document 3 (filler having a particle size of 0.1 to 1 μm plated with lead-free solder on the base material) is eliminated, the content of the entire filler in the conductive adhesive is reduced. Minute nanoparticle auxiliary fillers can be included without modification. In addition, since the lead-free solder ball (filler having a particle size of 0.1 to 1 μm) of Patent Document 3 is left as an auxiliary filler, compared to the case where the conductive filler is composed of only the main conductive filler and the nanoparticle auxiliary filler. The amount of expensive nanoparticle auxiliary filler used can be reduced while ensuring the reliability of conduction.

  In the exothermic glass of the present invention, the main conductive filler has a scaly shape or an elliptical shape, and its minor axis may be 1 to 10 μm, preferably 3 to 7 μm. The conductive adhesive is preferably 10 to 20% by weight of the organic resin, 50 to 85% by weight of the main conductive filler, and 5 to 40% by weight of the total of the auxiliary filler and the nanoparticle auxiliary filler. It may be included at a ratio of 5 to 25% by weight. The main conductive filler may be obtained by plating lead-free solder on the base material having a thermal conductivity of 250 to 500 W / m ° C. The lead-free solder plating of the main conductive filler is a solder whose melting point is 230 ° C. or less and whose main component is selected from Bi—Sn, In—Ag, Sn—Ag—Cu, Sn—Ag, and Sn—Cu. be able to. The auxiliary filler may be a solder having a melting point of 230 ° C. or lower and a main component selected from Bi—Sn, In—Ag, Sn—Ag—Cu, Sn—Ag, Sn—Cu, and Ag. The nanoparticle auxiliary filler may be a solder having a melting point of 230 ° C. or lower and a main component selected from Bi—Sn, In—Ag, Sn—Ag—Cu, Sn—Ag, Sn—Cu, and Ag. . In addition, the conductive adhesive contains a dispersant in a proportion of 1 to 5% by weight with respect to a total of 100 parts by weight of the organic resin, the main conductive filler, the auxiliary filler, and the nanoparticle auxiliary filler. Can do.

  In the method for producing a heat generating glass of the present invention, a transparent conductive film is formed on the surface of a glass plate, and a conductive adhesive is applied to the opposite position of the surface of the transparent conductive film and cured to form a pair of power supply electrode terminals. In the glass manufacturing method, the conductive adhesive contains an organic resin and a conductive filler, and the conductive filler includes a main conductive filler obtained by plating a substrate with lead-free solder, and the main conductive material. Auxiliary filler made of lead-free solder balls having a volume smaller than that of the conductive filler and a particle diameter of 0.1 to 1 μm, and a nanoparticle auxiliary filler made of lead-free solder having a volume smaller than that of the auxiliary filler and a particle diameter of 1 to 50 nm It is characterized by using what is comprised by these.

Embodiments of the present invention will be described below. The overall structure of the exothermic glass according to the present invention can be the same as the exothermic multi-layer glass shown in FIG. In other words, the heat-generating multilayer glass of FIG. 2 has two glass plates 10 and 12 arranged opposite to each other with a frame-like spacer 14 interposed therebetween. A transparent conductive film 16 made of ITO, SnO ₂ or the like is formed on the surface of one (usually indoor side) glass plate 10 facing the other glass plate 12. Electrode terminal pairs 18 and 20 constituting power supply terminals are formed at opposite end positions on the surface of the transparent conductive film 16. For example, the electrode terminal pairs 18 and 20 are formed by applying paste-like conductive adhesives 18a and 20a to the opposite end positions of the surface of the transparent conductive film 16 by screen printing or the like, and then applying flat knitted copper wires 18b and 20b thereon. The conductive adhesives 18a and 20a are cured and bonded to each other. Lead wires 22 and 24 are soldered to the flat knitted copper wires 18b and 20b of the electrode terminal pairs 18 and 20, respectively. When a voltage is applied between the lead wires 22 and 24 and the transparent conductive film 16 is energized, the transparent conductive film 16 generates heat and the glass plate 10 is heated.

  The composition of the conductive adhesives 18a and 20a will be described. The conductive adhesive paste constituting the conductive adhesives 18a and 20a is configured by mixing three kinds of conductive fillers in a binder made of an organic resin. A state in the conductive adhesive paste applied to the surface of the transparent conductive film 16 is schematically shown in FIG. In the binder 25 of the conductive adhesive paste, three kinds of conductive fillers are included in a mixed state. These three types of conductive fillers are composed of a main conductive filler 26 in which lead-free solder is plated on a base material, an auxiliary filler 28 made of lead-free solder balls having a volume smaller than that of the main conductive filler 26, and an auxiliary filler 28. Is a nanoparticle auxiliary filler 30 made of lead-free solder having a small volume.

  The conductive adhesive having the above composition is applied to the positions of the electrode terminal pairs 18 and 20 on the surface of the transparent conductive film 16 of the glass plate 10 and cured to adhere to the transparent conductive film 16. Lead-free solder plating of the main conductive filler 26 by the heat at the time of bonding (heat when the binder 25 is cured by heating in a heating furnace when the binder 25 is a thermosetting resin, or heat of melting of the resin when the binder 25 is a thermoplastic resin) Melts and the main conductive fillers 26 are fused. Also, the auxiliary filler 28 and the nanoparticle auxiliary filler 30 are melted to assist the fusion of the main conductive fillers 26. Thereby, the main conductive fillers 26 are electrically connected. In this fusion, the nanoparticle auxiliary filler 30 is fine particles of lead-free solder, so that it easily enters between the main conductive filler and the auxiliary filler, and also melts even at a relatively low temperature because of the fine particles. As a result, it becomes easier to fuse the main conductive fillers 26 and to improve the reliability of conduction. As a result, a large current can flow stably.

  The blending ratio of the three types of fillers 26, 28, and 30 contained in the conductive adhesive is preferably 50% by weight or more and 85% by weight or less for the main conductive filler 26 in order to reduce contact resistance. That is, when the main conductive filler 26 is less than 50% by weight, it becomes difficult for the main conductive fillers 26 to come into contact with each other, resulting in poor conduction. On the other hand, when the amount of the main conductive filler 26 exceeds 85% by weight, the amount of the organic resin component becomes small, and the adhesion strength with the adhesive surface (the surface of the transparent conductive film 16) decreases. The thickness of the lead-free solder plating on the surface of the main conductive filler 26 is preferably 0.5 to 2 μm. That is, if it is less than 0.5 μm, it becomes difficult to fuse the main conductive fillers 26, and the contact resistance becomes high. On the other hand, when the thickness is greater than 2 μm, the thermal conductivity of the main conductive filler 26 is lowered. The shape of the main conductive filler 26 is preferably a scale shape or an elliptical shape. By making the scale shape or the ellipse shape, the contact area between the main conductive fillers 26 can be increased as compared with the case of the spherical shape, the fusion between the main conductive fillers 26 can be promoted, and the contact resistance can be reduced. . The minor axis of the scale-like or elliptical shape of the main conductive filler 26 is 1 to 10 μm, preferably 3 to 7 μm.

  The base material of the main conductive filler 26 is preferably a material having high thermal conductivity (250 to 500 W / m ° C.), for example, a metal material such as silver, gold, copper, nickel, aluminum, SiC (silicon carbide), AlN ( Aluminum nitride) and the like. Lead-free solder plating of the main conductive filler 26 is Bi-Sn-based, In-Ag-based, Sn-Ag-Cu-based, Sn-Ag-based, Sn-Cu-based lead-free, which has a melting point of 230 ° C. or less and hardly oxidizes. An example is solder. The lead-free solder plating of the main conductive filler 26 can be performed by coating the base material with the lead-free solder selected from the above by the barrel method.

  Bi-Sn-based, In-Ag-based, Sn-Ag-Cu-based, Sn-Ag-based, Sn-Cu-based, and Ag-based materials that have a melting point of 230 ° C. or less and hardly oxidize as materials for the auxiliary filler 28 and the nanoparticle auxiliary filler Lead-free solder. The total amount of the auxiliary filler 28 and the nanoparticle auxiliary filler 30 is preferably 5 to 40% by weight. That is, when it is less than 5% by weight, the main conductive fillers 26 cannot be sufficiently fused together. On the other hand, if the amount is more than 40% by weight, the heat conductivity of the conductive adhesive becomes small, so that sufficient heat radiation cannot be performed and oxidation may occur. Furthermore, since the auxiliary filler 28 and the nanoparticle auxiliary filler 30 have small particle diameters, oxidation is likely to occur, and there is agglomeration as secondary particles, so the total of both is particularly preferably 5 to 25% by weight. The auxiliary filler 28 is formed in a spherical shape with a particle size of 0.1 to 1 μm. The nanoparticle auxiliary filler 30 is formed in a spherical shape with a particle size of 1 to 50 nm.

  The binder 25 containing an organic curing agent is preferably 10% by weight or more and 25% by weight or less. That is, if it is less than 10% by weight, the proportion of the filler is increased, and the adhesion strength with the adhesive surface (the surface of the transparent conductive film 16) is extremely deteriorated. On the other hand, if it exceeds 25% by weight, the binder 25 excessively enters between the main conductive fillers 26, making it difficult for the main conductive fillers 26 to be fused together and increasing the contact resistance. As the material of the binder 25, a thermosetting resin or a thermoplastic resin can be used. Examples of the thermosetting resin include an epoxy resin, a phenol resin, an acrylic resin, and a urethane resin. Examples of the thermoplastic resin include polyamide resin, polystyrene resin, and polyester resin.

  When a thermosetting resin is used as the material of the binder 25, it is preferable to select a lead-free solder for each of the fillers 26, 28, and 30 that has a melting point that is 20 to 30 ° C. lower than the curing temperature of the resin. Thereby, the lead-free solder is melted by heating for applying and curing the conductive adhesive, and the main conductive fillers 26 can be fused well. When lead-free solder with a melting point higher than the curing temperature of the thermosetting resin is used, heating at a temperature higher than the curing temperature of the thermosetting resin is required to fuse the main conductive fillers together. Will deteriorate. If lead-free solder whose melting point is too low is selected, the contact resistance becomes unstable because it melts even at low temperatures due to the heat generated when current flows.

  In addition, when a material having a small particle size is selected as the main conductive filler 26, it is preferable to add a dispersing agent and a reducing agent because they easily aggregate and easily oxidize. In that case, a dispersing agent is added in a ratio of 1 to 5% by weight with respect to a total of 100 parts by weight of the binder 25, the main conductive filler 26, the auxiliary filler 28, and the nanoparticle auxiliary filler 30.

  Moreover, the flux which consists of antioxidant, an acidic substance, or a rosin (pine resin) with respect to a total of 100 weight part of the binder 25, the main electroconductive filler 26, the auxiliary filler 28, and the nanoparticle auxiliary filler 30 in the ratio of 3 to 5 weight%. It may be added. That is, the lead-free solder plating of the main conductive filler 26 and the auxiliary filler 28 and the nanoparticle auxiliary filler 30 enter the fusion process from the contact at the heating temperature of the resin binder 25, but lead-free on the surface of each filler 26, 28, 30. The solder may have a relatively strong oxide film, and it is necessary to chemically activate the surface to promote the wettability of the solder. A flux composed of an antioxidant, an oxidizing substance, or rosin has a high ability to remove an oxide film and also improves the wettability of solder. In particular, rosin melts at 127 ° C. and its activity lasts up to about 315 ° C., making it an ideal chemical and physical flux. Abietic acid, the active ingredient of rosin, is inactive in solids, but becomes active when it is heated to a molten state, and becomes inactive again when it is cooled. It can be suitably used as a flux to be added to the agent.

The following materials (a), (b), (c) and (d) were mixed (total 100% by weight), and a rosin flux was further added to adjust the conductive adhesive.
(a) Binder 25: Epoxy resin binder. 20% by weight
(b) Main conductive filler 26: A base material composed of silver and plated with 60Sn40Bi solder having a melting point of 138 ° C. The minor axis is 3-5 μm. 60% by weight
(c) Auxiliary filler 28: Lead-free solder ball composed of 60Sn40Bi having a melting point of 138 ° C. The particle size is 1 μm. 12% by weight
(d) Nanoparticle auxiliary filler 30: lead-free solder ball composed of 60Sn40Bi having a melting point of 138 ° C. The particle size is 50 nm. 8% by weight.
The adjusted conductive adhesive is applied to a predetermined portion of the transparent conductive film 16 of the glass plate 10 (FIG. 2) (conductive adhesives 18a and 20a), and the flat knitted copper wires 18b and 20b are conductively bonded as connection terminals. It mounted on the agent 18a and 20a, and heat-processed for 20 minutes at 230 degreeC with the heating furnace. Thereafter, it was left to cool in the atmosphere and sufficiently cooled. After sufficient adhesion was confirmed, a direct current of 30 A was applied. As a result, the temperature of the resin at the terminal portion was as low as 70 ° C., the resistance value was as low as 0.7 mΩ, and no short circuit occurred even after 100 hours of application.

The following materials (a), (b), (c) and (d) were mixed (total 100% by weight), and a rosin flux was further added to adjust the conductive adhesive.
(a) Binder 25: Epoxy resin binder. 12% by weight
(b) Main conductive filler 26: The base material made of silver is plated with 48Sn52In solder having a melting point of 117 ° C. The minor axis is 3-5 μm. 70% by weight
(c) Auxiliary filler 28: Lead-free solder ball composed of 48Sn52In having a melting point of 117 ° C. The particle size is 1 μm. 8% by weight
(d) Nanoparticle auxiliary filler 30: lead-free solder ball composed of 48Sn52In having a melting point of 117 ° C. The particle size is 50 nm. 8% by weight.
The adjusted conductive adhesive is applied to a predetermined portion of the transparent conductive film 16 of the glass plate 10 (FIG. 2) (conductive adhesives 18a and 20a), and the flat knitted copper wires 18b and 20b are conductively bonded as connection terminals. It mounted on agent 18a, 20a, and heat-processed for 20 minutes at 200 degreeC with the heating furnace. Thereafter, it was left to cool in the atmosphere and sufficiently cooled. After sufficient adhesion was confirmed, a direct current of 30 A was applied. As a result, the temperature of the resin at the terminal portion was as low as 70 ° C., the resistance value was as low as 0.7 mΩ, and no short circuit occurred even after 100 hours of application.

Comparative example

The following materials (a), (b), (c), and (d) were mixed (total 100% by weight), and a rosin flux was further added to adjust the conductive adhesive described in Patent Document 3.
(a) Binder: Epoxy resin binder. 20% by weight
(b) Main conductive filler: constructed by plating 60Sn40Bi solder on a base made of silver. The minor axis is 3-5 μm. 60% by weight
(c) Auxiliary filler: constructed by plating 60Sn40Bi solder on a base material composed of silver. Particle size 1 μm. 15% by weight
(d) Lead-free solder balls: Lead-free solder balls composed of 60Sn40Bi. Particle size 1 μm. 5% by weight.
The adjusted conductive adhesive is applied to a predetermined portion of the transparent conductive film 16 of the glass plate 10 (FIG. 2) (conductive adhesives 18a and 20a), and the flat knitted copper wires 18b and 20b are conductively bonded as connection terminals. It mounted on agent 18a, 20a, and heat-processed for 20 minutes at 250 degreeC with the heating furnace. Thereafter, it was left to cool in the atmosphere and sufficiently cooled. After sufficient adhesion was confirmed, a direct current of 30 A was applied. As a result, the temperature of the resin at the terminal portion was as high as 105 ° C., the resistance value was as low as 1.5 mΩ, and short-circuited after 12 hours of application. From the results of the destructive test and the material analysis results, it was confirmed that the adhesion between the main conductive filler and the auxiliary filler was insufficient and the reliability was incomplete.

It is a schematic diagram which shows the state in the conductive adhesive paste which comprises the conductive adhesive used by this invention. It is a figure which shows embodiment of the heat generating glass of this invention, (a) is a cross-sectional side view, (b) is AA arrow sectional drawing of (a).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,12 ... Glass plate, 14 ... Spacer, 16 ... Transparent electrically conductive film, 18, 20 ... Electrode terminal pair, 18a, 20a ... Conductive adhesive, 18b, 20b ... Flat knitted copper wire, 22, 24 ... Lead wire, 25 ... Binder, 26 ... Main conductive filler, 28 ... Auxiliary filler, 30 ... Nanoparticle auxiliary filler

Claims (9)

A transparent conductive film is formed on the surface of the glass plate, a conductive adhesive is applied and cured on the opposite position of the surface of the transparent conductive film to form a pair of power supply electrode terminals, and a voltage is applied between the electrode terminals. In the heat-generating glass that heats the transparent conductive film by energizing the transparent conductive film,
The conductive adhesive contains an organic resin and a conductive filler, and the conductive filler has a main conductive filler in which a lead-free solder is plated on a base material and a volume smaller than the main conductive filler. It is composed of an auxiliary filler made of lead-free solder balls having a particle size of 0.1 to 1 μm and a nanoparticle auxiliary filler made of lead-free solder having a smaller volume than the auxiliary filler and a particle size of 1 to 50 nm. Characteristic exothermic glass.   The exothermic glass according to claim 1, wherein the main conductive filler has a scale shape or an ellipse shape, and a short axis thereof is 1 to 10 µm, preferably 3 to 7 µm.   The conductive adhesive is 10 to 25% by weight of the organic resin, 50 to 85% by weight of the main conductive filler, and 5 to 40% by weight of the total of the auxiliary filler and the nanoparticle auxiliary filler, preferably 5 The exothermic glass according to claim 1 or 2, which is contained at a ratio of -25% by weight.   The exothermic glass according to any one of claims 1 to 3, wherein the main conductive filler is obtained by plating lead-free solder on the base material having a thermal conductivity of 250 to 500 W / m ° C.   The lead-free solder plating of the main conductive filler is a solder whose melting point is 230 ° C. or less and whose main component is selected from Bi—Sn, In—Ag, Sn—Ag—Cu, Sn—Ag, and Sn—Cu. Item 5. The exothermic glass according to any one of Items 1 to 4.   The auxiliary filler is a solder having a melting point of 230 ° C. or lower and a main component selected from Bi—Sn, In—Ag, Sn—Ag—Cu, Sn—Ag, Sn—Cu, and Ag. The exothermic glass as described in any one.   The nanoparticle auxiliary filler is a solder having a melting point of 230 ° C or lower and a main component selected from Bi-Sn, In-Ag, Sn-Ag-Cu, Sn-Ag, Sn-Cu, and Ag. The exothermic glass according to any one of 5.   The conductive adhesive includes a dispersant in a proportion of 1 to 5% by weight with respect to a total of 100 parts by weight of the organic resin, the main conductive filler, the auxiliary filler, and the nanoparticle auxiliary filler. The exothermic glass according to any one of 1 to 7. In the method for producing exothermic glass, a transparent conductive film is formed on the surface of the glass plate, and a pair of electrode terminals for feeding is formed by applying and curing a conductive adhesive on the opposing position of the surface of the transparent conductive film.
The conductive adhesive contains an organic resin and a conductive filler, and the conductive filler has a volume that is larger than that of the main conductive filler and a main conductive filler obtained by plating a substrate with lead-free solder. It is composed of an auxiliary filler made of lead-free solder balls having a small particle size of 0.1 to 1 μm and a nano-particle auxiliary filler made of lead-free solder having a smaller volume than the auxiliary filler and a particle size of 1 to 50 nm. A method for producing exothermic glass, characterized in that

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