JPH0533482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a flexible thin keyboard switch member formed by printing a spacer layer, and in particular: used mainly for keyboard switches in electrical equipment. The present invention relates to a method of manufacturing a flexible thin keyboard switch member having a pair of contact portions and circuit portions, the main feature of which is printing and applying a spacer.

(Prior art and its problems) The conventional manufacturing method of this type of flexible thin keyboard switch member, that is, the keyboard switch board, consists of a gold-plated circuit board portion formed on a copper-clad phenol laminate as the substrate, and a contact point. A structure in which conductive rubber and a conductive rubber are placed facing each other and a separate spacer layer is interposed in between is used, and it is extremely difficult to make it so-called thin. Also, if this is required, it has the disadvantage that it becomes complicated and precise and extremely expensive.

Another important feature of the present invention is that desired circuits can be printed and dried easily and quickly on the two flexible films, making it possible to design circuits that could not be achieved with conventional copper-clad phenol laminates. , it becomes possible to bring about a degree of freedom in design.

The present invention was made in order to eliminate the above-mentioned conventional drawbacks and to seek the ideal, and it is possible to use a keyboard switch using a special resin for the spacer through an extremely simple manufacturing process. It is an object of the present invention to provide a method for manufacturing a flexible thin keyboard switch member provided with a flexible substrate.

(Means for Solving the Problems) As can be seen in the drawings, the method for manufacturing a flexible thin keyboard switch member according to the present invention includes: (a) particle size;
20 to 80% by weight of fine powder consisting of one or more of graphite powder with a particle size of 0.1 to 60 μ, carbon black powder with a particle size of 0.1 μ or less, and silver powder with a particle size of 0.1 to 60 μ; (b) polyurethane resin, chloroprene rubber, 5 to 30% by weight of a rubber-based, thermoflexible resin, and thermosetting resin binder consisting of one or more of polyester resins and phenolic resins, and (c) butyl cellosolve acetate, cyclohexanone, diacetone alcohol, and dimethyl. Formamide, diethyl carbitol, butyl carbitol, isophorone and turpentine mixed with 15-80% by weight of solvent (a+b+c)
Dissolved and uniformly dispersed apparent specific gravity 0.9-1.9,
Using a suspension having a viscosity of 150 to 10,000 poise, a desired circuit, its contact pattern 3 and connection terminal pattern 5 are formed on two flexible insulating film substrates 1 and 2 on one side, and on the other side. A step (A) of printing and drying opposing contact patterns 4 and connection terminal patterns 6 that are to be in contact with the desired circuit and the contacts and connection terminals using a screen printing method, respectively; and the printing and drying step (A). In the vicinity of at least one of the contact patterns 3 and 4 on the surfaces of the film substrates 1 and ₂ formed by
5 to 47% by weight, (b) 5 to 47% by weight of a thermosetting two-component urethane resin, (c) 0.5 to 20% by weight of an isocyanate crosslinking agent for accelerating curing and drying, and (d) isophorone. , diacetone alcohol, methyl isobutyl ketone, xylene, toluene, and diethyl carbitol.15
A spacer in which a desired spacer layer pattern is printed using a screen printing method using a suspension whose viscosity is adjusted to 50 to 5000 poise and is composed of ~80% by weight (A+B+C+D) and then dried. Layer formation process (B)
and the two printed film substrates 1 and 2.
and a step (C) of overlapping, positioning and fixing the contact parts 3 and 4 so as to face each other with the spacer layer part 7 interposed therebetween (A+B+C).

Here, if the conductive fine powder (a) is less than 20% by weight, the conductivity will be poor and cannot be used, and if it exceeds 80% by weight, the dispersibility will be poor and printability will also be poor and it cannot be used. . In addition, if the particle size is less than 0.1μ,
It is difficult and expensive to obtain, and there is no need for it. However, if it exceeds 60μ, the conductivity tends to become unstable and non-uniform, which is not acceptable. However, regarding carbon black powder,
Particles with a particle size larger than 0.1μ are difficult to obtain on the market, and even if available, there is no need for them, and particles with a particle size of 0.1μ or less can be used satisfactorily.

Next, if the amount of the above-mentioned (b) binder is less than 5% by weight, printability and adhesion will deteriorate and it is not acceptable.
If it exceeds 30% by weight, the conductivity will deteriorate further and it is not possible.

Furthermore, if the amount of the above-mentioned (c) solvent is less than 15% by weight, dissolution and dispersion will be insufficient, making it impossible to obtain a proper suspension, and if it exceeds 80% by weight, the suspension will be insufficient. It becomes too dilute and the viscosity becomes too low, which is unacceptable. Furthermore, if the apparent specific gravity of the suspension is less than 0.9, the conductivity will be poor and the printability will also be poor, making it unsuitable. On the other hand, if it exceeds 1.9, the printability will worsen and a uniform printed layer with electrical conductivity will not be obtained. Also, the viscosity of the suspension is
If it is less than 150 poise, the stability of the suspension cannot be obtained,
Further, uniform printing properties cannot be obtained, and therefore it is difficult to form a good conductive printed layer. on the other hand,
If it exceeds 10,000 poise, the viscosity will be too high and will impair uniform printability.

Furthermore, if the amount of TiO ₂ (a) is less than 5% by weight, it is not possible because the filler is insufficient and it becomes difficult to form a spacer layer having appropriate elasticity and thickness. If it exceeds 47% by weight, the amount as a filler becomes too large and becomes hard, making it impossible to obtain a spacer layer having appropriate elasticity and thickness.

Furthermore, if the amount of the thermosetting two-component urethane resin (b) is less than 5% by weight, the spacer layer becomes hard and loses proper elasticity; on the other hand, if it exceeds 47% by weight, Printability deteriorates, impairing printability and spacer layer formation.

Furthermore, if the amount of the isocyanate crosslinking agent for promoting curing and drying mentioned above (c) is less than 0.5% by weight, the effect of accelerating curing and drying will not be obtained.
If it exceeds % by weight, the effect will be saturated and it will be economically disadvantageous, and it will no longer be necessary.

Furthermore, the amount of the organic solvent (d) above is 15% by weight.
If it is less than 10,000 poise, the viscosity of the suspension (a + b + c + d) will exceed the specified 10,000 poise, which will lead to poor printability.
Adhesiveness also worsens and is no longer possible. 80% by weight
If the
It becomes less than 150 poise, which worsens printability and the formation of a spacer layer, making it unacceptable.

Furthermore, if the viscosity of the above-mentioned suspension (a+b+c+d) is less than 50 poise, the printability and spacer layer formation properties will deteriorate, making it impossible. On the other hand, if it exceeds 5000 poise, the printability will deteriorate and the spacer layer cannot be formed properly.

In addition, in the present invention, the suspension (a+b+c+
In addition to (d), a coloring agent such as a dye such as phthalocyanine green may be further added in an amount of about 0.2 to 5% by weight as the component (e).
This is for reasons of appearance and aesthetics.

(Function) In the present invention, the special above-mentioned (a) thermosetting two-component urethane resin is combined with the special (c) isocyanate-based crosslinking agent (hardening accelerating drying agent) for promoting hardening and drying. One major feature and effect is that a spacer layer having particularly good printability, rapid curing and drying properties, and appropriate elasticity and thickness can be formed by this method.

(Examples) Hereinafter, the present invention and examples will be further described using the drawings.

Example 1 (a) 30% by weight of graphite powder with a particle size of 0.1 to 60μ and particle size
Using a suspension (a + b + c) consisting of 15% by weight of carbon black of 0.1 μ or less, (b) 25% by weight of polyurethane resin, namely Paraprene 225 (trade name, manufactured by Nippon Polyurethane Co., Ltd.), and (c) 30% by weight of isophorone. As shown in Figures 1a and 1b, and 2a and 2b, by screen printing,
Two polyester film substrates 1 with a thickness of 50μ,
2, a predetermined conductive circuit, its contact patterns 3, 4, and connection terminal patterns 5, 6 are placed on one side of the
Each was printed and dried at a temperature of 100° C. for 15 minutes to form electrically conductive contact portions 3 and 4 and connection terminals 5 and 6, respectively (Step A).

Next, in the step A, the circuit and contact pattern 3,
4 and connecting terminals 5, 6 are printed on the surfaces of two polyester substrates 1, 2 (see FIGS. 2a and 2b) near the periphery of the contact pattern conductive parts 3, 4. ₂ 27% by weight, (b) 27% by weight of thermosetting two-component urethane resin, trade name: Crisbon 4070 manufactured by Dainippon Ink Co., Ltd., and (c)
Isocyanate-based crosslinking agent for accelerating curing and drying, that is, Dainippon Ink Co., Ltd. trade name drying curing agent Crysbon NX 7% by weight and (di)toluene 38
As an example, using a suspension with a viscosity of 1000 poise consisting of (e) 1% by weight of dye (coloring agent) phthalocyanine green (i + b + c + d + e), As shown in FIGS. 3a and 3b, a desired spacer layer pattern 7 having a total thickness of 125 μm is printed by screen printing method,
It was dried at a temperature of 100° C. for 15 minutes to form a spacer layer 7 (Step B).

The polyester film substrate 1 that has been printed in step B is turned over as shown in FIG. 4a, and placed oppositely on the other substrate 2 formed in step A as shown in FIG. 4b, As shown in FIGS. 5a and 5b, the contact portions were positioned and fixed in an overlapping manner so that they corresponded to each other and faced each other (step C).

At this time, the obtained flexible substrate for a keyboard switch, that is, a flexible thin keyboard switch member, exhibited excellent elasticity and exhibited sufficient practicality as a keyboard switch. As shown in Figure 5b, pressing in the direction of the arrow closes the switch, and releasing the pressure opens the switch.

The manufacturing process of the present invention is extremely suitable for mass production such as a printing process, and the process can be shortened, making it possible to respond to low costs.

(Effects) According to the present invention, it is possible to provide a manufacturing method that can easily and quickly print a cushionable spacer layer to manufacture a flexible thin keyboard switch member. By easily printing and applying the spacer layer and quickly curing and drying it, a flexible thin keyboard switch member can be obtained.

[Brief explanation of the drawing]

FIGS. 1a and 1b are perspective schematic views showing a film substrate, which is the starting material for step A in an embodiment of the present invention, respectively, and FIGS. 2a and 2b are
3a and 3b are schematic perspective views showing a film substrate provided with contacts, connection terminals, and a circuit pattern on one side of the film board in the step A, respectively.
The figure is a schematic perspective view showing a spacer pattern provided near the periphery of the contact pattern of the film substrate shown in FIGS. 2a and 2b by step B, and FIG. 4a is a schematic perspective view showing the film substrate shown in FIGS. Figure 4b is a cross-sectional view of the board cut along the -' line of Figure 3b and placed facing the substrate of Figure 4a;
The figure shows a schematic perspective view showing a keyboard switch member in which both the substrates shown in FIGS. 4a and 4b are stacked and fixed in a process C with both contact portions facing each other, and further, FIG. FIG. 3 is a sectional view taken along the line -' in the figure. 1, 2... Flexible insulating film substrate, 3, 4...
...Printed contact pattern, 5, 6...Printed connection terminal pattern, 7...Spacer layer pattern.

Claims (1)

[Scope of Claims] 1 (a) 20 to 80% by weight of fine powder consisting of one or more of graphite powder with a particle size of 0.1 to 60μ, carbon black powder with a particle size of 0.1μ or less, and silver powder with a particle size of 0.1 to 60μ.
and (b) one or two of polyurethane resin, chloroprene rubber, polyester resin, and phenolic resin.
(c) butyl cellosolve acetate, cyclohexanone, diacetone alcohol, dimethylformamide, diethyl carbitol, butyl carbitol, Mixture of isophorone and turpentine with 15-80% by weight of solvent (a+
b+c) Apparent specific gravity dissolved and uniformly dispersed
Using a suspension with a viscosity of 0.9 to 1.9 and a viscosity of 150 to 10,000 poise, a pattern of the desired circuit and its contacts and connection terminals is formed on two flexible insulating film substrates on one side and on the other. , a step (A) of printing and drying patterns of opposing contacts and connecting terminals that should come into contact with the desired circuit and the contacts and connecting terminals using a screen printing method; and in the printing and drying step (A). Near the periphery of at least one of the contact patterns on the surface of the formed film substrate, (a) anatase-type or rutin-type TiO ₂
5 to 47% by weight, (b) 5 to 47% by weight of a thermosetting two-component urethane resin, (c) 0.5 to 20% by weight of an isocyanate crosslinking agent for accelerating curing and drying, and (d) isophorone. , diacetone alcohol, methyl isobutyl ketone, xylene, toluene, and diethyl carbitol.15
A spacer in which a desired spacer layer pattern is printed using a screen printing method using a suspension with a viscosity of 50 to 5,000 poise made up of ~80% by weight (A + B + C + D) and dried. Layer formation process (B)
and the step (C) of overlapping and positioning and fixing the two printed film substrates so that the bonded portions correspond and face each other via the spacer layer portion (A+B+C). A method for manufacturing a flexible thin keyboard switch member characterized by: