JPH0477570

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DESCRIPTION JPH0477570
[0001]
FIELD OF THE INVENTION The present invention relates to a piezoelectric buzzer and a paint for
forming an electrode thereof. [Prior Art] As shown in FIG. 1, in a piezoelectric buzzer, electrodes
2 are formed on both sides of a piezoelectric vibrator 1 and lead wires 4 are connected to the
electrodes 2 directly or through a metal elastic body 3. It is. Silver paste is conventionally used
for the electrodes 2 in this piezoelectric buzzer, and as shown in FIG. 3, the silver paste is applied
to both surfaces of the piezoelectric vibrator 1 by printing to form the electrodes 2, and
thereafter, Drying and baking are performed according to the flow shown in FIG. [Problems to be
Solved by the Invention] The piezoelectric vibrator 1 of the piezoelectric buzzer is desired to be
as thin as possible from the viewpoint of vibration characteristics. However, if the thickness is
reduced, silver migration may occur in the electrode 2 when a direct current voltage is applied in
a wet atmosphere after the baking (about 800 ° C.) in the conventional manufacturing method
such as drying and baking, etc. There is a problem that 1lllI can not be achieved. As a method of
achieving the above-mentioned thin film formation, there is known a method of heat curing a
coating of a conductive paste consisting of metallic silver powder and a thermosetting resin, but
in this case, the conductivity is lowered and it is formed on the insulating substrate. There were
problems such as poor adhesion of the coating. Therefore, the object of the present invention is
to solve the problems of the above-mentioned conventional silver paste, (1) having good
conductivity, (2) screen printing, intaglio printing, being a good item, (2) coating on insulating
substrate Good adhesion, ■ can form fine line circuits, ■ has excellent solderability and strength
with solder on films, and ■ proposes nickel pastes that can maintain the conductivity of
conductive circuits of solder coats over a long period of time It is in. (Means for Solving the One
Problem) In order to solve the above-mentioned problems, in the present invention, 85% to 96%
by weight of metallic nickel powder A, 815 to 4% by weight of resol type phenolic resin, and both
of them A And 0.1 to 8 parts by weight of a saturated fatty acid or unsaturated fatty acid or
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metal salt thereof and 1 to 50 parts by weight of a metal chelate-forming material, based on 100
parts by weight of the total of B, Are the 2-, 2-, 2.4-, 63-, 2-, 4-, 4-methyl-, 2-, 2-methyl, methylol,
dimethylene ethers that they possess, as well as the infrared transmittance of the phenyl group
by 1, 1, When n, a, b and c, (i)-= 0.8 to 1.2 (ii)-= 0.8 to 1.2 (iii)-0, 8 between each permeability.
From a paste that holds the following relationship: ˜ 1.2 (D)-1, 2 to 1.5 It had adopted a
piezoelectric buzzer electrode forming coating.
The metal nickel powder A has an average particle size of 0 ° to 2071111, preferably 1 n or
less. Then, on both surfaces of the piezoelectric vibrator, electrodes made of the paste having the
above-described configuration are formed, and a piezoelectric buzzer formed by connecting a
lead wire directly or via an elastic body to this electrode is configured. [Function] In the nickel
paste according to the present invention configured as described above, when the compounding
amount of the metallic nickel powder is less than 85% by weight, the solderability deteriorates
and conversely, when it exceeds 96% by weight, the metallic nickel powder becomes It is not
sufficiently bound, the resulting electrode is also poor, the desired soldering strength can not be
obtained, the conductivity is lowered and the screen printability is also deteriorated. Preferably,
the blending ratio with the resin is 88% by weight or more, more preferably 90 to 93% by
weight. With respect to the resol type phenol resin to be used, its stoichiometry, the amount of 21 substitution is λ, the amount of 2.4-2 substitution is p, the amount of 2.4.6-3 substitution is
ν, the amount of methylol group is α When the amount of dimethylene ether is β and the
amount of phenyl group is T, the fact that 1 ′ ′ of the above constitution is large means that J
− is smaller by n ν. That is, it means that V is larger in the amount of 2.4.6-3 substituents
compared to the amount of 2-1 substituents λ and the amount of 2.4-2 substituents μ. In
addition, when the two of the above-mentioned constitution is large, α becomes 17 that is
small, that is, the amount of methylol group α is larger than the amount of dimethylene ether β
and the amount of phenyl group T. It means that. Generally, the crosslink density of the resoltype phenolic resin is increased when the 2.4.6-3 substituted compound amount 大 き く is
increased. The smaller the 小 さ い is, the more ν 、, that is, the "L", the larger the conductivity
of the electrode is better. However, conversely, the electrode tends to be hard and brittle, and the
physical properties deteriorate. Also, if the size is small, the solderability of the electrode is poor,
and if the size is large, the conductivity of the electrode is poor. α Therefore, as a resol type
phenolic resin which makes the hardness of the obtained electrode appropriate and combines
good conductivity and solderability, z b shown in the above-mentioned constitution is 0.8 to 1.2,
n n respectively a) It is suitable that Y is 1.2 to 1.5. When the amount of the resol-type phenolic
resin is less than 4% by weight, the metal nickel powder is not sufficiently bound, the obtained
electrode is also brittle, the conductivity is lowered and the screen printability is deteriorated.
On the other hand, when it exceeds 15% by weight, solderability is not preferable. With saturated
fatty acids or unsaturated fatty acids or metal salts thereof, in the case of saturated fatty acids,
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C16-C20 palmitic acid, stearic acid, arachic acid and the like, in unsaturated fatty acids, such as
C16-18 carbon seamarins In the case of acids, belenic acid, lyric acid and the like, the metal salts
thereof are salts with metals such as potassium, copper, aluminum, sodium and zinc. The use of
these dispersants is preferable because it promotes the fine dispersion of the metal nickel
powder in the resin and forms an electrode of good conductivity in the combination of the metal
nickel powder and the resol-type phenolic resin. The compounding amount of the saturated fatty
acid or the unsaturated fatty acid or the metal salt thereof is used in the range of 0.1 to 8 parts
by weight with respect to 100 parts by weight in total of the metal nickel powder and the resol
type phenol resin, It is 3 parts by weight. When the compounding amount of the dispersing agent
is less than 0.1 parts by weight, fine dispersion of the metallic nickel powder can not be
expected, and conversely, when it exceeds 8 parts by weight, the conductivity of the electrode is
lowered and the electrode and piezoelectric vibration are It is not preferable because it leads to a
decrease in adhesion with the child. As the metal chelating agent, at least one selected from
aliphatic amines such as monoethanolamine, jetanolamine, triethanolamine, ethylenediamine,
triethylenediamine, triethylenetetramine and the like is used. The metal chelating agent to be
added prevents the oxidation of the metallic nickel powder, contributes to maintaining the
conductivity, and further improves the solderability. The compounding amount of the metal
chelating agent is in the range of 1 to 50 parts by weight with respect to the total amount of 1.00
parts by weight of the metallic nickel powder and the resol type phenolic resin. If the
compounding amount of the metal chelating agent is less than 1 weight, the conductivity is
lowered and the solderability is not preferable. On the other hand, when the amount is more than
50 parts by weight, the viscosity of the paste itself is excessively lowered to adversely affect the
printability, which is not preferable. In the nickel paste according to the present invention, in
order to adjust the viscosity, an ordinary solvent 411 can be suitably used. For example, known
solvents such as butyl carpitol, butyl carpitol acetate, butyl cellosolve, methyl isobutyl ketone,
toluene, xylene and the like. [Example] Particle size 1. n metal nickel powder, resol type phenol
resin of infrared transmittance ratio shown in Table 1, oleic resin potassium, and triethanolamine
are compounded (parts by weight) in the proportions shown in Table 2 respectively, and some
butyl carpitol as a solvent In addition, the mixture was kneaded with a three-wheeled roll for 20
minutes to prepare a nickel paste.
In particular, in Example 3, the average particle diameter of the metallic nickel powder: 1-1 and 2
had the same average particle diameter: 0.5 Jlll. The respective embodiments are applied to both
surfaces of the pseudo substrate of the piezoelectric vibrator 1 by screen printing as shown in
the flow of FIG. 2 to form the electrodes 2, and in order to observe various characteristics of the
electrodes 2, first of all, Each piezoelectric vibrator 1 with the electrode 2 is immersed for 4
seconds in an organic acid type flux tank and then for 5 seconds in a 250 ° C. molten solder
tank (Pb / 5n-40 / 60) and pulled up. It was washed after blowing hot air at 2 to 6.0 atm and
220 to 230 ° C. At this time, the average thickness of the solder coat soldered to the electrode 2
was 10 n. Table 2 shows the results of examining various characteristics of the electrode 2
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obtained in this process. Here, the conductivity of the electrode is a value obtained by measuring
the volume resistivity of the heat-cured electrode 2. With the adhesion of the electrode, in
accordance with the foundation test method of JIS K5400 (1979), 11 parallel lines perpendicular
to each other are drawn at intervals of 1 m + on the coating film to be an electrode, and 100 in 1
cii. The base-like cuts were made so that individual grids could be made, and when the coating
was peeled off with cellophane tape from above, the number of bases of the coating ˜ remaining
on the insulating substrate was determined. . The solderability was evaluated by observing the
state of being soldered on the electrode 2 with a low magnification stereomicroscope and by the
following criteria. ○: Smooth on the surface, with solder adhering to the entire surface Δ:
Partially exposed electrode × ×: With only solder partially attached Printability is adjusted with
viscosity When forming the electrode 2 by the screen printing method using the obtained 2nd
paste, the easiness of the printing was observed and evaluated by the following criteria. O mark:
good formation of the pole 2 Δ mark: difficult to form the electrode 2 x mark: difficult to form
the electrode 2 Next, the soldering strength is the glass epoxy resin substrate A coating film of
25 to 30 tna in thickness is formed on a land of 3 diameter 画 on G10 (for example, G10) and
heated at 130 to 180 ° C. for 10 to 60 minutes to cure the coating film. Solder the lead wires (0,
8 ++ mφ tin plated soft copper wire) vertically on the lands vertically (using 63 Sn eutectic
solder), fix the substrate and make the lead wires perpendicular at a tension rate of 50 wa / min.
The tensile strength is determined. As is apparent from this result, in each example, the specific
compounding materials are appropriately combined, so the conductivity of the electrode (coating
film), the adhesion of the electrode, the solderability, the solderability, the printability And other
characteristics are good.
Further, direct soldering can be performed on the obtained cured electrode using a conventional
organic acid flux agent. Next, with regard to the comparative example, in the comparative
example 1.2.3, since the infrared transmittance ratio of the resol-type phenol resin to be used is
not appropriate, the electrode 2 having preferable solderability can not be obtained. The
comparative example 4 is not preferable because the solder adheres only to a part of the
piezoelectric vibrator 1 in soldering because the amount of the metal 2 · 2 kel powder is small. In
Comparative Example 5, the metal nickel powder is large and the metal nickel powder is not
sufficiently bound, so the conductivity of the electrode is unstable, the obtained electrode 2 is
also rough, and the screen printability is often difficult and not preferable. . [Effects of the
Invention] As described above in detail, since the piezoelectric bushing formed with the electrode
using the paint for electrode formation according to the present invention does not require
baking at the time of electrode formation, the productivity is improved, and Since there is no fear
of migration in the subsequent wet atmosphere, the baking has the effect of achieving thinning of
the piezoelectric vibrator.
[0002]
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Brief description of the drawings
[0003]
FIG. 1 is a schematic view of an embodiment of a piezoelectric buzzer according to the present
invention, FIG. 2 is a diagram for explaining the fabrication of the embodiment, and FIG. 3 is a
diagram for explaining the conventional fabrication.
1 ··· Piezoelectric vibrator, 2 · · · · · · · · · · · · · · · · · · · · · · · metal elastic body, 4 · · · · · · lead wire.
Below margin table Below margin Fig. 1 Fig. 2 Fig. 3
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