JPH0323492B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for firing a paste for sheet glass used as automobile window glass or the like. (Prior Art) Automobile window glasses are bonded to the window frame through urethane, etc., but recently the surrounding area has been bonded to prevent deterioration of the bonded area from ultraviolet rays and to hide the rags, as shown in Figure 1. There is a plate glass 1 with a black ceramic color 2 printed on its periphery. On the other hand, conventionally, in the case of rear window glass, a conductive wire 3 containing silver is printed for the purpose of defogging, and a bus bar 4 is used to supply power to the conductive wire 3.
It is known that the following is printed on the side edge of the glass 1. These conductive wires 3 and bus bars 4 are both formed by firing silver paste, and the ceramic collar 2 is also formed by firing ceramic paste. Since the parts to be formed are the same, after printing ceramic paste on the inside surface of the glass plate, we then print a layer of silver paste on this surface, and then bend and form the glass plate in this state, taking advantage of the temperature during bending. The ceramic paste and silver paste are then fired. (Problems to be Solved by the Invention) As mentioned above, a ceramic paste is printed on the surface of a plate glass, a silver paste is printed on top of the ceramic paste, and these are heated at the glass forming temperature (600 to 700
℃), the low melting point lead glass (frit) in the ceramic paste will diffuse into the silver paste, and the silver component ratio in the bus bar 4 after firing will decrease. When the silver component ratio in the bus bar decreases, there is a disadvantage that the adhesive strength of the terminals soldered to the bus bar 4 decreases. For this reason, conventionally, as shown in Figure 1,
Either a part of the bus bar 4 protrudes from the ceramic collar 2 and the terminal 5 is glued to this protruding part, or a cutout part 6 is provided in a part of the ceramic collar 2 as shown in FIG. The terminal 5 is glued so that it is located at the . However, with the configuration shown in Figure 1, the terminals are visible from the outside, which is unfavorable in terms of design.Also, since the terminals are located more centrally, there are problems in that the conductor wires must be lengthened accordingly. As shown in FIG. 2, providing a notch 6 in a part of the ceramic collar 2 is troublesome to print and is disadvantageous in terms of cost. On the other hand, in order to increase the adhesive strength of the terminals, it is possible to plate the bus bars, but sufficient adhesive strength has not been obtained. The above-mentioned problem is not limited to the adhesion between the bus bar and the terminal provided on the rear window, but also applies to the adhesion between the antenna wire and the power supply terminal provided on the front window or the like. (Means for Solving the Problems) The present invention proposes that if the thickness of the silver paste is large, the amount of silver components remaining after firing will increase, and the firing temperature and the silver paste of low melting point lead glass in the ceramic paste will increase. It was discovered that there is a certain relationship with the amount of diffusion into the interior, and based on this, the above problem was solved. Specifically, the part where the power supply terminal is soldered and bonded is made of ceramic paste and silver paste. In addition to overprinting in two layers, the glass surface temperature (T) during firing and the thickness (h) of the silver paste after firing are:
It was made such that 4μ≦h≦15μ and T≦100log h+570°C. (Example) An example of the present invention will be described below with reference to FIGS. 3 and 4. In the embodiment, a case will be described in which sheet glass is bent and formed. FIG. 3 is a sectional view showing the main parts of the bent glass 11 according to the present invention. A ceramic collar 12 made by firing ceramic paste is formed at the inner end of the bent glass 11, and the ceramic collar 12 is formed by firing a ceramic paste. A bus bar 14 made of baked silver paste is formed on the top, and a conductive wire 13 (hot wire) made of baked silver paste is integrally formed from a part of this bus bar 14 in the width direction of the glass plate 11. There is. A power supply terminal 15 is soldered to a part of the bus bar 14. Here, in order to obtain the above-mentioned bent glass 11, ceramic paste and silver paste are overlapped and printed on the side edges of the flat glass, and after drying each paste, the flat glass is placed in a heating furnace and softened. This flat glass is heated to almost a point, and then placed in a bending machine and bent into a curved shape using the space between the molds or the weight of the glass plate. Use and fire. Next, the experimental results when bent glass was manufactured under various conditions are shown in [Table]. In the table, observation item (1) indicates the quality of firing of the ceramic color (thickness after construction is 10 to 15 μm).
The ○ mark indicates good firing, and the x mark indicates poor firing. This determination was made by applying it to the printed surface using an oil-based felt-tip pen and checking whether or not it oozed out onto the glass surface. Observation item (2) is the result of measuring the silver component ratio (%) after polishing using an X-ray microanalyzer, and observation item (3) is Sn64wt%,
The adhesive strength (Kg・f) is shown when a terminal is bonded to the busbar surface using Pb36wt% solder. The symbol ▲ indicates that the adhesive was not bonded. Regarding ceramic pastes, we prepare ceramic pastes for low-temperature firing for laminated glass, ceramic pastes for medium-temperature firing for self-weight strengthening, and ceramic pastes for high-temperature firing for press strengthening. Ingredient ratio is low melting point lead glass: 55~
80wt%, inorganic pigment: 10~35wt%, oil 10~
25wt%, and the component ratio of silver paste is silver: 68 ~
88wt%, low melting point lead glass: 2-5wt%, oil 10
~30wt%.

[Table] As is clear from this [Table], the terminal adhesive strength increases as the proportion of silver in the busbar increases, and especially when considering the generally required terminal adhesive strength of 20 kg・f, The silver component ratio in the subsequent bus bar must be 60% or more. Furthermore, the higher the glass forming temperature, the lower the proportion of silver in the bus bar, the lower the temperature of the ceramic paste and silver paste, the better the firing, and the thicker the silver paste (bus bar) after firing, the better the silver content. The ratio of the ingredients becomes large. In this way, the forming temperature (glass surface temperature) when bending sheet glass, silver print (bus bar)
There is a predetermined relationship between the thickness of the terminal and the adhesive strength of the terminal, and this relationship is shown in the graph of FIG. In Figure 4, ○, ▽, and □ marks are high temperature firing (approximately 620℃) and intermediate firing (approximately 580℃), respectively.
And when the silver paste is fired at a low temperature (approximately 560°C), the glass surface temperature (T°C) that exhibits a terminal bonding strength of 20 kg・f and the thickness of the silver paste (silver print) after firing (hμ) This is a point that shows. And regardless of the firing temperature, it is always 20
In order to exhibit terminal adhesive strength of Kg・f or more, the fourth
It is necessary to perform firing under conditions that satisfy the region below line segment a in the figure. Therefore, as a result of inductively calculating a function that satisfies line segment a, T = 100log h + 570℃
The following formula was obtained. Therefore, in the area below line segment a, T≦
It will be expressed as 100log h+570℃. If the glass surface temperature (molding temperature) and the thickness of the silver print after firing are satisfied within this range, a plate glass with terminals bonded with the required adhesive strength can be obtained. (Effects of the Invention) As explained above, according to the present invention, even when ceramic paste and silver paste are fired at the same time when forming a glass plate, sufficient silver components remain in the formed silver paste. Therefore, the power supply terminal can be firmly bonded, and unlike conventional methods, the terminal can be bonded in a position away from the ceramic collar.
There is no need to provide a notch in the ceramic collar, which is extremely advantageous in terms of design and manufacturing.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional plate glass, Fig. 2 is a sectional view showing an end of a conventional plate glass, Fig. 3 is a sectional view showing an end of a plate glass according to the present invention, and Fig. 4 is a sectional view after firing. It is a graph showing the relationship between the thickness of a silver print and the glass surface temperature during molding.

Claims (1)

[Claims] 1. In a method in which ceramic paste and silver paste are overprinted on a part of the surface of a plate glass and then fired, a power supply terminal is soldered, the part to which the power supply terminal is soldered is made of ceramic paste and silver. The paste is overprinted in two layers, and the glass surface temperature (T) during firing and the thickness (h) of the silver paste after firing are 4μ≦h≦15μ, and T≦100.
A method for firing a paste for plate glass, characterized by satisfying log h+570°C.