WO2012118203A1

WO2012118203A1 - Method for joining automobile window glass to electricity supply terminal

Info

Publication number: WO2012118203A1
Application number: PCT/JP2012/055456
Authority: WO
Inventors: 西　瑞樹; 貴之小川; 下岡　泰真; 一範古橋
Original assignee: セントラル硝子株式会社
Priority date: 2011-03-02
Filing date: 2012-03-02
Publication date: 2012-09-07
Also published as: JP2014096198A

Abstract

Disclosed is a method that is for joining an automobile window glass to an electricity supply terminal and that contains: a first step wherein, using a lead-free solder alloy, a solder layer is formed by heat welding to a predetermined location on a conductive wire formed on the surface of the automobile window glass; a second step for forming a solder layer by heat welding to the terminal seat of the electricity supply terminal; a third step for positioning the surface of the solder layer formed in the second step to the solder layer formed in the first step; a fourth step for further heating both solder layers using a heater having a controlled heating temperature, thus welding and joining both solder layers together; and a fifth step for cooling by controlling the cooling temperature.

Description

Bonding method of automotive window glass and power supply terminal

The present invention relates to a method of joining a metal terminal called a power feeding terminal to an automobile window glass.

Background of the Invention

In recent years, attempts have been made to impart various characteristics using vehicle window glass. For example, there is an antifogging element called a defogger or a glass antenna. The defogger is composed of a plurality of resistance heating wires disposed horizontally and in parallel over almost the entire surface of the glass plate, and two conductive wires called bus bars for supplying power to the ends of the resistance heating wires. . The two bus bars are arranged opposite to the left and right sides of the glass plate, and have a wiring width wider than that of the resistance heating line in order to supply sufficient power to the resistance heating line. An electric current is passed between the bus bars, whereby the resistance heating wire generates heat and warms the glass plate, thereby preventing poor visibility due to condensation.

Such a bus bar is made by screen-printing a silver paste composed of glass frit, silver particles and an organic binder on a glass plate, and then drying and baking it.

In the defogger, the current is supplied from a power supply terminal soldered to a predetermined location on the bus bar. In the glass antenna, current is taken out from the power supply terminal.

Conventionally, the power supply terminal and the bus bar are connected by solder containing lead. However, lead is a highly toxic environmental pollutant. In addition to adverse effects on health, adverse effects and pollution on the environment, especially the ecosystem, are regarded as problems. Therefore, there is a strong social demand not to use lead as much as possible. Many industries, including the consumer electronics industry, have already used low-lead or lead-free solder for various soldering applications. Such a movement is similar to the solder for the vehicle, and the movement to make the solder for the vehicle lead-free is rapidly spreading.

However, it is very difficult to satisfy the characteristics conventionally required with low-lead or lead-free solder in the use of glass plates for vehicles. This is mainly because household appliances are used indoors, whereas glass plates for vehicles are used outdoors, so they must endure a poor environment. In addition, safety issues are extremely important, and are required to pass, so they must pass a severe test. For this reason, for example, the customer is required to pass a cooling / heating cycle test or a salt spray test, but it cannot be easily passed.

Furthermore, for the purpose of enhancing the antiglare performance, or for the purpose of concealing the heat ray terminals and the like from the outside, a ceramic having a black or near-tone color (hereinafter referred to as a black ceramic) opaque layer is formed on the glass plate. There are many glass plates on the market that are coated and baked on the periphery. Since such a glass plate is often provided with a bus bar on the black ceramic layer, the solder used to connect the power supply terminal and the bus bar has characteristics not only for the bus bar but also for the black ceramic layer. There are also circumstances that must be taken into account. 7 and 8 show an example of a glass plate in which a black ceramic layer is applied to the periphery of the glass plate, dried and baked. For the black ceramic layer, a paste made of glass frit and pigment is printed on the surface of the glass plate by screen printing in a predetermined shape, dried and fired at 600 ° C. to 700 ° C., and the black ceramic layer adheres firmly to the glass plate. Formed in a state.

Patent Documents

1 and 2 disclose lead-free solders that do not contain lead, which is a harmful substance, and have sufficient bonding strength to oxide materials such as glass and ceramics.

Patent Document 3 discloses a vehicle glass panel that pays attention to generation of stress in a glass plate after soldering with a lead-free solder alloy.

Further, Patent Document 4 discloses an electrical connector for a vehicle window glass plate using solder composed of less than 70 parts of Sn together with a reaction rate adjusting agent larger than 30 parts.

Further, in Patent Document 5, a vehicle window glass plate preheated in a range from a temperature lower by 100 ° C. to a temperature higher by 10 ° C. than the melting point of lead-free solder is used to heat the bonding portion of the terminal and lead the vehicle window by lead-free solder. A soldering method for bonding a terminal to a conductor of a glass plate is disclosed.

Furthermore, Patent Document 6 discloses a lead-free solder composition containing tin, indium, silver and bismuth and a method and apparatus for joining to an automotive glass plate using two types of solder.

JP 2000-1441078 A JP 2000-326088 A JP-T-2006-523917 JP 2008-218399 A JP 2008-236516 A Special table 2009-504411

In conventional joining with lead solder, soldering is applied only to the power supply terminal of the automobile window glass, and the automobile window glass and its power supply terminal are joined using a sintered body of silver paste and flux. This method is advantageous in that it is simple and low in cost.

In recent years, lead-free solder alloys have been used mainly due to environmental problems. For lead-free solder alloys, a method for soldering only the power supply terminals, which is almost the same as the conventional method, has been studied. In this method, cracks in the solder hardly occur, but cracks tend to occur frequently at the interface between the solder and the sintered silver paste or the interface between the silver paste sintered and the black ceramic. Such cracks are likely to occur especially after a cold cycle test or a salt spray test. For this reason, the use of lead-free solder alloys has been strongly demanded by customers, but it has been able to cope only with various limited conditions. In particular, this problem is remarkable in the window glass for automobiles coated with black ceramics.

In the article described in Patent Document 3, a mechanical stress relaxation component is shown, and it is presumed that it leads to an increase in bonding strength, but it does not improve the characteristics for the cold cycle test and the salt spray test.

The composition and method described in Patent Document 6 are epoch-making in that two types of solder are used, but they do not improve the characteristics for the cold cycle test and the salt spray test. Further, in the two types of solder, for example, the upper layer solder is said to have a lower melting temperature than the lower layer solder, and there are some which are difficult to manage during manufacture.

As described above, in the conventional technology, when lead-free solder alloy is used, the joining strength of the power feeding terminal is not sufficient, and the thermal cycle and the salt spray test cannot be passed. For this reason, in the glass plate for vehicles, there was a restriction | limiting naturally to using a lead-free solder alloy. The present invention has been made in view of the above-described problems, and an object of the present invention is to increase the bonding strength of a power supply terminal made of a lead-free solder alloy, particularly in the case of an automotive window glass coated with black ceramics.

The present invention is a method for soldering a window glass and a power supply terminal with a lead-free solder alloy through a conductive wire made of a sintered body of a silver paste formed by coating on the surface of an automotive window glass,
A first step of forming a solder layer by heat-welding to a predetermined location on a conductive wire using a lead-free solder alloy used for soldering a window glass and a power supply terminal;
A second step of forming a solder layer by heat-welding to the terminal seat of the power supply terminal;
A third step of aligning the solder layer formed in the first step and the surface of the solder layer formed in the second step;
A fourth step in which both solder layers are heated with a heater with a controlled heating temperature, and both solder layers are welded together and joined together;
This is a method (first method) for joining an automotive window glass and a power supply terminal, characterized by comprising a fifth step of cooling by controlling the cooling rate.

The first method may be a method of joining the window glass for an automobile and its power supply terminal (second method) in which the thickness of the solder layer in the first step is 0.2 mm or more and 3 mm or less.

The first or second method is a joining method (third method) of an automotive window glass and its power supply terminal, wherein the heat welding temperature of the lead-free solder alloy in the first step is not lower than the melting point and not higher than the melting point + 100 ° C. Also good.

Any one of the first to third methods is a joining method (fourth method) of an automotive window glass and its power supply terminal, in which the lead-free solder alloy is heat-welded in the first step using ultrasonic waves. There may be.

Any one of the first to fourth methods is a method of joining an automotive window glass and its power supply terminal (fifth), wherein the thickness of the solder layer in the second step is not less than 0.5 mm and not more than 5 mm. Method).

Any one of the first to fourth methods is a joining method (sixth method) of an automotive window glass and its power feeding terminal, wherein the joining temperature in the fourth step is not lower than the melting point and not higher than the melting point + 100 ° C. Also good.

In any one of the first to sixth methods, the cooling rate after joining in the fifth step is controlled by cooling at a cooling rate of 5.0 ° C./sec or more by blowing air, The window glass and its power feeding terminal joining method (seventh method) may be used.

Any one of the first to seventh methods includes: an automotive window glass having a black ceramic layer, and a sintered body of silver paste is heat-welded on the black ceramic layer. A joining method (eighth method) of glass and its power supply terminal may be used.

Any one of the first to eighth methods may be a method for joining an automotive window glass and its power supply terminal (the ninth method) in which the lead-free solder alloy is In-Ag-Sn solder.

Any one of the first to eighth methods may be a method of joining an automotive window glass and its power supply terminal (tenth method), in which the lead-free solder alloy is Sn—Ag—Cu solder.

In the present invention, a part of the lead-free solder alloy used for joining the window glass and the power supply terminal is previously deposited on the silver paste sintered body, and the lead-free solder alloy is heat-welded to the silver paste sintered body. There is a feature in doing. By performing the heat welding in the first step, a large bonding strength can be obtained between the solder and the glass plate surface by an interface reaction with the glass plate through the sintered body of the silver paste.

Next, as a second step, heat-welding is also performed on a power supply terminal for an automobile window glass using a part of the lead-free solder alloy. By performing the heat welding in the second step, a large bonding strength can be obtained between the solder and the metal material surface of the power supply terminal.

In this way, the solder layer surfaces of both the power supply terminal and the window glass, on which the solder layer is separately formed in advance, are aligned in the third step, and both the solder layers are heated and welded together in the fourth step. Let In this fourth step, it is only necessary to heat both solder layers and weld and bond the two solder layers, and if the surfaces of both solder layers are welded, sufficient adhesive strength can be obtained. ), The bonding strength is maintained without remelting the interface between the window glass and the solder layer heat-welded in the first step and the interface between the power supply terminal and the solder layer heat-welded in the second step. .

Note that the order of the first step and the second step is not limited. Further, it is desirable that the solder alloys used in the first step and the second step have the same composition. That is, two types of lead-free solder alloys are not fused to bond the solders together, but may be joined using the same lead-free solder alloy. It is quite difficult to successfully fuse two types of lead-free solder alloys having very different compositions, and an interface may occur between the two types of lead-free solder alloys. When such an interface occurs, a problem of heat shrinkage occurs on the interface, or salt water enters. Therefore, if the alloy composition does not cause such an interface to reduce the bonding strength, the solder composition used in the first step and the second step may be slightly different or an improved component may be added. Good.

The bonding strength was measured according to JIS C60068. Measured by bending the connection part of the power supply terminal after the thermal cycle test and salt spray test so as to be perpendicular to the terminal seat, and pulling the connection part in a direction perpendicular to the joint surface using a push-pull gauge. When the power supply terminal was not peeled off, it was determined that the adhesive strength was good.

According to the present invention, even when an automotive window glass and a metallic material, particularly a metallic terminal called a power feeding terminal are joined using a lead-free solder alloy, the joining strength can be increased. In particular, a thermal cycle test and salt water that reproduces the situation where glass with lead terminals joined using lead-free solder alloy is held for a long time in a harsh environment against solder in areas where the temperature difference between day and night is large or near the coast. Even after the spray test, the bonding strength of the power supply terminal to the glass with the lead-free solder alloy can be sufficiently maintained.

It is a cross-sectional conceptual diagram which shows the state which joined the electric power feeding terminal to the glass plate by the method of this invention. It is a cross-sectional conceptual diagram which shows the state which joined the electric power feeding terminal to the glass plate by the method of a prior art. It is a conceptual diagram of this invention which shows a mode that the lead-free solder alloy is heat-welded on the sintered body of the silver paste placed on the black ceramic layer in the first step. In a 4th step, it is a conceptual diagram of this invention which shows a mode that the electric power feeding terminal for window glass for motor vehicles, and the window glass for motor vehicles are joined. It is a conceptual diagram of this invention which shows a mode that the heat melting of the lead-free solder alloy made to adhere on the sintered compact of a silver paste is made using an ultrasonic soldering iron. It is a conceptual diagram which shows a mode that when a lead-free solder alloy is provided on the sintered body of a silver paste in a 1st step, a thread-like solder is heated with a soldering iron and it is made the molten solder. It is the front schematic of the glass plate in which the black-like ceramic layer was formed. FIG. 8 is a cross-sectional view taken along the line aa ′ of FIG.

Detailed description

A mode for carrying out the present invention will be described below.
The present invention relates to a method of joining a conductive wire of a window glass for an automobile and a feeding terminal with a lead-free solder alloy. The conductive wire is formed of a silver paste sintered body. In the first step, a lead-free solder alloy is heat-welded on the silver paste sintered body to form a solder layer. In the second step, a lead-free solder alloy is heat-welded to the terminal seat of the power supply terminal to form a solder layer. In the third step, the solder layer formed in the first step and the surface of the solder layer formed in the second step are aligned. Further, in the fourth step, both the solder layers are heated by a heater whose heating temperature is controlled, and both the solder layers are welded and bonded together. In the fifth step, the cooling rate is controlled to quench.

FIG. 2 is a conceptual cross-sectional view showing a state in which a power supply terminal is joined to a predetermined location on a glass bar bus bar by a conventional method. The glass plate 1, the black ceramic layer 2, the silver paste sintered body 3 and the power supply terminal 6 are joined by solder 5. Further, when the power supply terminal 6 is viewed in large size, the power supply terminal 6 includes a connection portion 10 with an external power supply element and a power supply terminal seat 11 attached to the glass plate. In general, the power supply terminal 11 has two seats, but there may be one or three or more.

FIG. 1 is a conceptual cross-sectional view showing a state in which a feeding terminal is joined to a predetermined location on a glass plate bus bar by the method of the present invention. A black ceramic layer 2 is disposed on the glass plate 1. The black ceramic paste is applied on the glass plate 1 and then dried. Further, a silver paste is applied and dried on the dried black ceramic paste. Furthermore, it is common that the black ceramic paste and the silver paste are simultaneously sintered and strengthened in a glass strengthening furnace.

On the silver paste sintered body 3, the lead-free solder alloy layer 4 applied in the first step and the lead-free solder alloy layer 5 applied in the second step coexist. Further, the power supply terminal 6 is on the lead-free solder alloy layer 5 applied in the second step. The power supply terminal 6 is often made of brass, but the material is not limited. Although the general shape of the power supply terminal 6 is shown in FIG. 1, the shape of the power supply terminal is many and is not limited to this shape.

FIG. 3 is a view showing a state in which a lead-free solder alloy 4 is heated and welded by a soldering iron (heater) 7 on a sintered body of silver paste placed on black ceramics in the first step. FIG.

FIG. 4 is a conceptual diagram of the present invention showing a state in which a power feeding terminal for an automobile window glass and an automobile window glass are joined in the fourth step. The lead-free solder alloy heat-welded in the first step and the second step heats both solder layers with a heater 9 or the like at a temperature not lower than the melting point and not higher than the melting point + 50 ° C. for not shorter than 3 seconds and not longer than 30 seconds. After being welded and joined together, air is blown at a cooling rate of 5.0 ° C./sec or more to cool to room temperature.

Generally, lead-free solder alloys are harder than leaded solder alloys and do not easily deform. For example, Sn—Ag—Cu lead-free solder is not easily deformed because it is surrounded by a eutectic structure composed of an intermetallic compound of Ag ₃ Sn and Cu ₆ Sn ₅ that is difficult to deform around the Sn crystal. . However, when this eutectic structure cannot prevent the deformation and the deformation starts, the deformability until the breakage is low, and therefore, the eutectic structure is easily broken. Therefore, in order to stabilize the mechanical properties of the Sn—Ag—Cu lead-free solder, it is necessary to control the metal structure. The molten Sn—Ag—Cu lead-free solder is rapidly cooled to suppress the growth of Sn crystals, reduce the crystal size as much as possible, and quickly precipitate the eutectic structure. Due to the rapid cooling, the Sn crystal and the eutectic structure become a finely mixed metal structure, and the eutectic structure that prevents deformation is dispersed, so that the ability to prevent deformation is reduced, the deformation is easily deformed, and the deformability up to fracture is reduced. Due to the large structure, the mechanical properties can be stabilized.

The cooling rate in the fifth step is preferably 5.0 ° C./sec or more. The more rapidly cooled, the finer the solder structure. When the cooling rate is smaller than this, the metal structure of the lead-free solder alloy is not stable, the toughness of the solder is lowered, and sufficient bonding strength cannot be obtained. The cooling rate is more preferably 6.0 ° C./sec or more. More preferably, it is 7.0 ° C./sec or more.

In the present invention, it is desirable that the thickness of the lead-free solder alloy in the first step is 0.2 mm or more and 3 mm or less. If the thickness is less than 0.2 mm, a problem that good bonding strength cannot be obtained occurs. On the other hand, when it exceeds 3 mm, the problem which looks worse arises. More preferably, the thickness is 0.3 mm to 2 mm, and still more preferably 0.4 mm to 1.5 mm. In addition, about lead-free solder alloy, it does not necessarily become a uniform thickness in all, but since the area differs somewhat, it is better to interpret the above-mentioned value as an average value.

In the present invention, it is desirable that the heat welding temperature of the lead-free solder alloy in the first step is not lower than the melting point and not higher than the melting point + 100 ° C. If the temperature is lower than the melting point, a problem that the lead-free solder alloy does not melt occurs. On the other hand, when the melting point exceeds + 100 ° C., fine cracks and the like are generated on the glass plate, and as a result, there is a problem that good bonding strength cannot be obtained. Furthermore, since time is required for cooling, the problem that production efficiency falls arises. More preferably, it is melting | fusing point +10 degreeC or more and melting | fusing point +80 degreeC or less, More preferably, it is melting | fusing point +20 degreeC or more and melting | fusing point +50 degreeC or less. Here, the melting point is measured by a general differential thermal analyzer.

Also, in the present invention, as shown in FIG. 5, it is desirable that the lead-free solder alloy is heat-welded in the first step using an ultrasonic soldering iron. By using an ultrasonic soldering iron, the bonding strength of the silver paste with the sintered body can be further increased. In addition, it is desirable that the application time of ultrasonic waves be 0.5 seconds or more and 20 seconds or less. If the time is less than 0.5 seconds, a problem that good bonding strength cannot be obtained occurs. On the other hand, if it exceeds 20 seconds, the characteristics of the sintered body of the silver paste change, and it may not be possible to join the lead-free solder alloy. More preferably, they are 1 second or more and 15 seconds or less, More preferably, they are 2 seconds or more and 10 seconds or less.

In the present invention, it is desirable that the lead-free solder alloy in the second step has a thickness of 0.5 mm to 5 mm. If the thickness is less than 0.5 mm, a problem that good bonding strength cannot be obtained occurs. On the other hand, when it exceeds 5 mm, the problem which looks worse arises. More preferably, it is 0.8 mm or more and 4 mm or less, More preferably, it is 1 mm or more and 3 mm or less.

In the present invention, as a third step, the relative positions of the two solder layers are aligned and fixed using a positioning jig or the like.

In the present invention, it is desirable that the bonding temperature in the fourth step is not less than the melting point and not more than the melting point + 50 ° C. If the temperature is lower than the melting point, a problem that the lead-free solder alloy does not melt occurs. On the other hand, when the melting point exceeds + 50 ° C., fine cracks and the like are generated on the glass plate. In addition, it takes time to cool the lead-free solder alloy, and the eutectic structure that prevents deformation of the lead-free solder alloy is not dispersed, so the deformation prevention ability is improved, the structure is difficult to deform, and the deformability until breakage is reduced. By doing so, the mechanical properties become unstable, resulting in a problem that good bonding strength cannot be obtained. Furthermore, since time is required for cooling, the problem that production efficiency falls arises. More preferably, the melting point is not lower than the melting point and not higher than the melting point + 40 ° C., and further preferably not lower than the melting point and not higher than the melting point + 30 ° C. In the present invention, before joining the power supply terminal and the conductive wire of the automobile window glass, the soldering is performed in advance on the terminal seat of the power supply terminal and the predetermined position on the conductive wire of the window glass of the automobile. For this reason, heat is easily transmitted to the solder, and even if the heating temperature is lowered, the bonding strength is exhibited. For example, a predetermined adhesive strength can be obtained even at a temperature of melting point + 30 ° C. or lower.

Further, in the present invention, it is particularly useful when the window glass for automobile has a black ceramic layer and a sintered body of silver paste is heat-welded on the black ceramic layer. Conventionally, the window glass for automobiles having a black ceramic layer has a higher temperature in a portion where the black ceramic paste is applied in a heating process during processing than in other portions. Therefore, when the sintered body of the silver paste is present on the black ceramic layer, the silver paste is overfired more than usual during the sintering, and the adhesive strength with the power supply terminal tends to be small.

In the present invention, as a preferable lead-free solder alloy, there is an In—Ag—Sn solder. Further, the desirable composition thereof will be described below. In-Ag—Sn solder composed of 26% by weight to 56% by weight In, 0.1% by weight to 5% by weight Ag, and the balance of Sn. . If In is less than 26% by weight, the Young's modulus increases, and the glass plate may be cracked. On the other hand, if In exceeds 56% by weight, the adhesive strength of the lead-free solder alloy is reduced due to residual internal stress due to the phase change of In ₃ Sn / In ₃ Sn + InSn ₄ and the occurrence of cracks even at a temperature change near room temperature. More preferably, it is 28 to 54 weight%. More preferably, it is 31 to 51 weight%. The amount of Ag added in the present invention is preferably 0.1% by mass or more and 5% by mass or less. By adding Ag, an effect excellent in improving the mechanical strength of the lead-free solder alloy is exhibited. Further, in a glass plate for a vehicle, a defogger heat wire and an antenna wire are formed by screen printing-drying-firing silver paste, and a power supply terminal that contacts the silver wire and the vehicle body is connected by a lead-free solder alloy. At this time, in order to prevent silver wire corrosion (so-called silver erosion) by the lead-free solder alloy, it is effective to add Ag to the lead-free solder alloy. However, if it is less than 0.1% by mass, these effects are low, and if it exceeds 5% by mass, coarse Ag ₃ Sn precipitates, which causes a decrease in strength and fatigue strength. Preferably they are 0.5 weight% or more and 3 weight% or less, More preferably, they are 0.8 weight% or more and 2 weight% or less.

Also, the melting point is preferably 90 ° C. or higher and 200 ° C. or lower. A lead-free solder alloy of less than 90 ° C. cannot be easily obtained. On the other hand, when it exceeds 200 ° C., there arises a problem that the bonding strength is lowered. More preferably, it is 95 degreeC or more and 180 degrees C or less, More preferably, it is 100 degreeC or more and 160 degrees C or less. However, it is not necessarily limited to these conditions.

Furthermore, in the present invention, Sn-Ag-Cu solder is another desirable lead-free solder alloy. Further, the desirable composition thereof will be described below. Sn—Ag composed of 94 wt% to 97 wt% Sn, 2 wt% to 5 wt% Ag, and 0.5 wt% to 2 wt% Cu. -Cu solder. When Sn is less than 94% by weight, there arises a problem that basic characteristics as a lead-free solder alloy are deteriorated. On the other hand, if it exceeds 97% by weight, there arises a problem that the bonding strength becomes weak. More preferably, they are 94.5 weight% or more and 96.5 weight% or less. Further, when Ag is less than 2% by weight, there arises a problem that the bond strength between the silver paste and the sintered body is weakened. On the other hand, if it exceeds 5% by weight, there will be a problem that fine cracks are generated on the surface of the lead-free solder alloy and the mechanical properties are lowered. More preferably, it is 2.2 to 4.5 weight%, More preferably, it is 2.5 to 3.8 weight%. Further, if Cu is less than 0.5% by weight, the bond of the intermetallic compound between Ag ₃ Sn becomes weak, and there arises a problem that the bonding strength decreases with time. On the other hand, if it exceeds 2% by weight, the lead-free solder alloy becomes hard and brittle, which causes a problem that the bonding strength is lowered. More preferably, they are 0.7 weight% or more and 1.8 weight% or less, More preferably, they are 0.8 weight% or more and 1.7 weight% or less.

Also, the melting point of Sn—Ag—Cu solder is almost limited to 210 ° C. or higher and 230 ° C. or lower.

Hereinafter, the present invention will be described in detail by way of examples. Here, the cold cycle test, the salt spray test, and the adhesive strength test refer to the following tests. The details will be described below.

[Cool cycle test]
A thermal cycle test according to JIS C2807 was performed. That is, 20 ° C. (3 minutes) → −30 ° C. (30 minutes) → 20 ° C. (3 minutes) → 85 ° C. (30 minutes) → 20 ° C. (3 minutes) The bonding strength was measured. In JIS C2807, the high temperature side temperature is the same as 85 ° C., but the low temperature side temperature is −25 ° C., which is more moderate than the test in this example.

[Salt spray test]
A salt spray test according to JIS Z2371 was conducted. That is, a 5% NaCl aqueous solution was continuously sprayed at a spraying pressure of 0.1 MPa for 100 hours in an atmosphere at 35 ° C., and the bonding strength after the test was measured.

[Joint strength test]
This was performed according to JIS C60068. Bonding strength is measured by bending the connecting part of the power supply terminal so that it is perpendicular to the terminal seat and pulling the connecting part in a direction perpendicular to the joint surface using a push-pull gauge. Those that did not peel off were determined to have good adhesive strength.

[Example 1]
First, after applying a black ceramic paste comprising a low melting point glass frit mainly composed of Bi-based borosilicate glass, a black inorganic pigment, an inorganic filler, and a solvent mainly composed of pine oil to a glass plate sample, it is once dried, On top of that, a silver paste composed of a fine melting point of silver particles, a low melting point glass frit mainly composed of Bi-based borosilicate glass, and a solvent mainly composed of terpineol is applied, and after drying, heated to 700 ° C. in a glass strengthening furnace. Then, the paste was fired and the glass plate was tempered simultaneously by rapid cooling. In this way, a tempered glass plate sample similar to a commercially available automobile window glass provided with a sintered body of silver paste was prepared.

As a first step, a general flux was thinly spread on the sintered body of silver paste. Thereafter, about 0.3 g (weight per one place) of a lead-free solder alloy having a diameter of 1.6 mm manufactured in a thread shape was melted and thickened to a thickness of about 1.5 mm on the sintered body of the silver paste. At this time, as shown in FIG. 6, the thread-shaped lead-free solder alloy 12 is a lead-free solder alloy 13 in a molten state at the tip of the soldering iron 7. The composition of the lead-free solder alloy used here was 51% by weight of In, 1% by weight of Ag, 48% by weight of Sn, and its melting point was 115 ° C. The melting point was measured according to JIS Z3198-1, and was measured using a differential type differential thermal balance TG8120 manufactured by Rigaku Corporation. Further, the lead-free solder alloy was heated for about 5 seconds on the sintered body of the silver paste, and was deposited on the sintered body of the silver paste. The temperature of the soldering iron was adjusted so that the lead-free solder alloy temperature was a predetermined temperature.

Next, as a second step, flux was applied to the terminal seating surface of the power feeding terminal made of C2801P (brass plate) whose material was specified in JIS H3100 as inverted. Thereafter, while dissolving about 0.4 g of the above-mentioned thread-shaped lead-free solder alloy per soldering iron, 0.8 g in total was deposited on the two bearing surfaces per terminal so that the thickness was about 2 mm. Therefore, the total amount of lead-free solder alloy in the first step and the second step is about 0.7 g per location, and the ratio of the amount of lead-free solder alloy in the first step to the amount of lead-free solder alloy in the second step is about 0.8.

Further, as a third step, the terminals and the glass plate are fixed with clips by aligning the positions of the respective solder layers heated and welded in the first step and the second step, and as a fourth step, the temperature of the lead-free solder alloy is about 140. 4. Heater (Stainnel Co., Ltd.) adjusted to 0 ° C. is applied for 8 seconds to heat both solder layers and weld and bond the two solder layers, and then, as a fifth step, air is blown. It cooled to 30 degreeC with the cooling rate of 0 degreeC / sec. The temperature of the lead-free solder alloy at this time was measured using a data logger AM-7012L manufactured by Anritsu Keiki Co., Ltd., with a thermocouple installed in the vicinity of the lead-free solder alloy.

The initial bonding strength of the five power supply terminals bonded in this way was measured. As a result, it was confirmed that all values exceeding 80N required in the market were exceeded.

Then, after the thermal cycle test (100 cycles), the results of examining the bonding strength exceeded all the values of 80N required in the market. Moreover, the joint strength after the salt spray test (after 100 hours) was also carried out. As a result, it exceeded all 80N values required in the market.

As a result of the above, it was confirmed that even when a lead-free solder alloy was used, it exceeded the value required in the market of 80N.

[Example 2]
A tempered glass plate sample almost the same as in Example 1 was prepared. As a first step, a general flux was thinly spread on the sintered body of the silver paste. Thereafter, about 0.03 g (weight per one place) of a lead-free solder alloy having a diameter of 1.6 mm produced in a thread shape was melted and deposited on the silver paste sintered body to a thickness of about 0.4 mm. The composition of the lead-free solder alloy used here is 95.2% by weight of Sn, 3.8% by weight of Ag, 1% by weight of Cu, and its melting point is 215 ° C.

Next, as a second step, flux was applied to the terminal seat surface of the inverted power feeding terminal. Thereafter, while melting the above-mentioned lead-free solder alloy with a soldering iron, about 0.2 g was deposited on one seating surface per terminal so that the thickness was about 1 mm. Accordingly, the total amount of lead-free solder alloy in the first step and the second step is about 0.23 g per location, and the ratio of the amount of lead-free solder alloy in the first step to the amount of lead-free solder alloy in the second step is about It was 0.2.

Further, as the third step, the terminals and the glass plate are fixed with clips by aligning the positions of the solder layers heated and welded in the first step and the second step, and in the fourth step, the lead-free solder alloy temperature is about 230 ° C. After heating the solder layers (made by Steinel) for 22 seconds to heat both solder layers and welding the two solder layers together, as a fifth step, air was blown to 5.0 It cooled to 30 degreeC with the cooling rate of (degreeC) / sec. The temperature of the lead-free solder alloy at this time was measured using a data logger AM-7012L manufactured by Anritsu Keiki Co., Ltd., with a thermocouple installed in the vicinity of the lead-free solder alloy.

The initial bonding strength of the five power supply terminals bonded in this way was measured. As a result, it was confirmed that it exceeded all 80N values required in the market.

[Example 3]
A tempered glass plate sample almost the same as in Example 1 was prepared. As a first step, a general flux was thinly spread on the sintered body of the silver paste. After that, using an ultrasonic soldering iron manufactured by Eishin Kogyo Co., Ltd., melt about 0.3 g of lead-free solder alloy with a diameter of 1.6 mm (weight per part) on the silver paste sintered body while melting it. The height was about 1.5 mm. At that time, ultrasonic waves were oscillated for about 2 seconds. The composition of the lead-free solder alloy used here was 51% by weight of In, 1% by weight of Ag, 48% by weight of Sn, and its melting point was 115 ° C.

Next, as a second step, flux was applied to the terminal seat surface of the inverted power feeding terminal. Thereafter, about 0.6 g of the above lead-free solder alloy was piled up with a soldering iron so that the thickness was about 3 mm. Accordingly, the total amount of lead-free solder alloy in the first step and the second step is about 0.9 g per location, and the ratio between the amount of lead-free solder alloy in the first step and the amount of lead-free solder alloy in the second step is About 0.5. The conditions other than those described above were the same as in Example 1.

As a result of the above, it was confirmed that even when a lead-free solder alloy was used, it exceeded the value required in the market of 80N. Since the bonding strength was measured with a push-pull gauge, a clear strength difference could not be measured, but it seemed stronger than the bonding strength in Example 1 and Example 2. Therefore, the push-pull gauge was set to 200N, and the initial strength, as well as the joint strength after the cooling / heating cycle test (100 cycles) and after the salt spray test (100 hours) were measured. It was over.

[Comparative Example 1]
A glass plate sample produced under substantially the same conditions as in Example 1 was prepared. For the lead-free solder alloy, a lead-free solder alloy having the same composition as in Example 1 was used. Further, the same soldering iron as in Example 1 was used. Moreover, it performed by what is called the conventional method of performing only by Step 2 without dividing Step 1 and Step 2. At this time, the amount of the lead-free solder alloy was about 0.55 g per one place. Other conditions were the same as in Example 1.

Then, after the thermal cycle test (100 cycles), the bonding strength was examined. As a result, 2 samples out of 5 samples were less than 80N, compared with 80N which is the value required in the market. Moreover, the joint strength after the salt spray test (after 100 hours) was also carried out. As a result, 3 samples out of 5 samples were less than 80N, compared with 80N which is a value required in the market.

[Comparative Example 2]
A glass plate sample produced under substantially the same conditions as in Example 2 was prepared. As for the lead-free solder alloy, a lead-free solder alloy having the same composition as in Example 2 was used. Moreover, it performed by what is called the conventional method of performing only by Step 2 without dividing Step 1 and Step 2. At this time, the amount of the lead-free solder alloy was about 0.43 g per one place. Other conditions were the same as in Example 2.

The initial bonding strength of the five power supply terminals bonded in this way was measured. As a result, one sample out of five samples was less than 80N with respect to 80N which is a value required in the market.

After that, after the thermal cycle test (100 cycles) was conducted and the joint strength was examined. As a result, 4 out of 5 samples were less than 80N, compared to 80N which is a value required in the market. It was. Moreover, the joint strength after the salt spray test (after 100 hours) was also carried out. As a result, 4 samples out of 5 samples were less than 80N against 80N which is a value required in the market. *

From the above, Examples 1, 2, and 3 of the present invention were all good, with bonding strengths exceeding 80 N immediately after soldering, after the thermal cycle test and after the salt spray test. On the other hand, in Comparative Examples 1 and 2 soldered only in Step 2 without separating Step 1 and Step 2, there is a sample whose adhesive strength immediately after soldering, after the thermal cycle test and after the salt spray test is less than 80N. It was not good.

1 Automotive window glass 2 Black ceramic layer 3 Sintered silver paste 4 Lead-free solder alloy applied in the first step 5 Lead-free solder alloy applied in the second step 6 Feed terminal 7 Heater (soldering iron)
8 Ultrasonic heater (ultrasonic soldering iron)
9 Heater 10 Connection portion 11 with external power supply element 11 Power supply terminal seat 12 adhering to glass plate Thread-like lead-free solder alloy 13 Lead-free solder alloy in molten state

Claims

In a method of soldering a window glass and a power supply terminal with a lead-free solder alloy via a conductive wire made of a sintered body of a silver paste formed by coating on the surface of an automotive window glass,
A first step of forming a solder layer by heat-welding to a predetermined location on a conductive wire using a lead-free solder alloy used for soldering a window glass and a power supply terminal;
A second step of forming a solder layer by heat-welding to the terminal seat of the power supply terminal;
A third step of aligning the solder layer formed in the first step and the surface of the solder layer formed in the second step;
A fourth step in which both solder layers are heated with a heater with a controlled heating temperature, and both solder layers are welded together and joined together;
A method for joining an automotive window glass and a power supply terminal, comprising a fifth step of cooling by controlling a cooling rate.
The method for joining an automotive window glass and its power supply terminal according to claim 1, wherein the thickness of the solder layer in the first step is 0.2 mm or more and 3 mm or less.
The method for joining an automotive window glass and its power supply terminal according to claim 1 or 2, wherein the heat welding temperature of the lead-free solder alloy in the first step is not lower than the melting point and not higher than the melting point + 100 ° C.
4. The method for joining an automotive window glass and its power supply terminal according to claim 1, wherein the lead-free solder alloy is heat-welded in the first step using ultrasonic waves. .
5. The window glass for an automobile according to claim 1, wherein the thickness of the solder layer in the second step is not less than 0.5 mm and not more than 5 mm. Terminal joining method.
6. The method for joining an automotive window glass and its power supply terminal according to any one of claims 1 to 5, wherein the joining temperature in the fourth step is not lower than the melting point and not higher than the melting point + 50 ° C.
The control of the cooling rate after joining in the fifth step is controlled by cooling at a cooling rate of 5.0 ° C / sec or more by blowing air to the joined part. The joining method of the window glass for motor vehicles described in and its electric power feeding terminal.
The window glass for automobiles has black ceramics, and a sintered body of silver paste is heat-welded on the black ceramics, according to any one of claims 1 to 7. Method of automobile window glass and its power supply terminal.
9. The method for joining an automotive window glass and its power supply terminal according to claim 1, wherein the lead-free solder alloy is In—Ag—Sn solder.
9. The method of joining an automotive window glass and its power supply terminal according to claim 1, wherein the lead-free solder alloy is Sn—Ag—Cu solder.