JP2000243175A - Key pad with resin key top and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise damp-proofing to improve reliability and productivity by adhering a key pad made of silicone rubber to a resin key top through an adhesive formed with a photo-curing resin in which a silane compound is contained in a prescribed ratio. SOLUTION: An adhesive for the key pad of silicone rubber having good weatherproofing, heat resistance, precise moldability, electric insulation, and the like, favorably contains silane compound, shown in the formula, of 0.1-20 pts.wt. in photo-curing resin of 100 pts.wt. By improvement of adhesion, the use of an ABS resin or the like of low softening point, quickening of adhesion, and prevention of dislocation are realized, and damp-proofing is improved. It is ideal to process a part of the connecting part of the key pad by shorter wavelength ultraviolet irradiation, corona discharge, flame, or plasma, and the adhesion becomes strong. in the formula, R1: vinyl group, methacryl group, acryl group, epoxy group, R2: chlorine, carbon number 1-6 of alkoxy group, 2-methoxy-ethoxy group, acetoxy group; R3: methyl group, ethyl group; at n=1, m=2 or 3, at n=2, m=2}.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aesthetically pleasing keypad with a resin key top for use in portable telephones, portable information terminals, remote controls for various home appliances, card remote controls, and various keyboards. The present invention relates to the manufacturing method.

[0002]

2. Description of the Related Art Conventional keypads have cold resistance, heat resistance,
Silicone rubber and the like have been mainly used as members because of their excellent weather resistance, precision moldability, and electrical insulation. The key top part is a soft type using the rubber of the base part,
A hard type obtained by bonding separately molded resin is used. Above all, a type in which a resin key top is bonded to a silicone rubber key pad has been particularly frequently used in recent years because of the high degree of design freedom such as the shape of the key top portion and tactile sensation.

On the other hand, silicone rubber is inherently poor in adhesiveness, and can be manufactured only by using a specific material and manufacturing method when manufacturing a type in which a resin key top of a bonded type is bonded. No high adhesive strength was obtained and the productivity was not high. However, by performing the surface treatment on the silicone rubber sufficient adhesion strength can not be obtained, the degree of freedom in material and production method have been proposed a method to significantly improve the (Japanese Open Gantaira 9-323932 discloses), silicone rubber A keypad made of resin and a key top made of resin
A resin with a low softening point such as BS resin can be used, and the bonding work can be performed quickly. There is no displacement during bonding, and a key with high productivity and a resin key top. Pads can now be manufactured.

[0004]

Among the proposals disclosed in Japanese Patent Application No. 9-323932, a photocurable resin is used as an adhesive for bonding a surface-treated silicone rubber and a resin keytop. The type is particularly effective because of its high workability and productivity. However, the type using the photo-curable resin is under high temperature and high humidity (60 ° C, relative humidity 95%, continuous 2
At 40 h), the adhesive durability (hereinafter, moisture resistance) was insufficient. As a countermeasure, a method of applying a primer such as a primer has been proposed in Japanese Patent Application No. Hei 9-323932, but such an application of a primer only increases the number of steps. However, there are many problems such as dimensional change due to the undercoat penetrating into the silicone rubber and swelling thereof, and occurrence of an effective time of the undercoat, and a photocurable resin adhesive having higher productivity has been desired.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a keypad with a resin keytop and a method for manufacturing the same, which has solved the problems of adhesiveness, productivity and moisture resistance. Stronger bonding between silicone rubber keypad and resin key top is possible, and it is possible to use hard resin with low softening point as represented by ABS resin. In addition, a keypad with a resin keytop having high productivity and high moisture resistance can be obtained without displacement during bonding. That is, 0.1% of the silane compound
A keypad with a resin keytop and a method for manufacturing the same, wherein the keypad is bonded with an adhesive which is a photocurable resin containing up to 20 parts by weight.

[0006] The addition amount of the silane compound of the present invention is 0.1 to
20 parts by weight is preferred, but more preferably 2 parts by weight to 15 parts by weight.
It is in the range of parts by weight. If the amount is less than 0.1 part by weight, the effect on the moisture resistance is not sufficient, and if it exceeds 20 parts by weight, the adhesive strength is undesirably reduced. Further, the silane compound of the present invention has the following chemical formula (Chemical Formula 1) (R ₁ contains at least one functional group selected from a vinyl group, a methacryl group, an acryl group or an epoxy group, R ₂ represents a chlorine group, Number 1
6, a functional group selected from an alkoxy group, a 2-methoxyethoxy group or an acetoxy group, and R ₃ is a methyl group or an ethyl group. When n is 1, m is 2 or 3, and when n is 2, m is 2).

Embedded image

The photocurable resin of the present invention is a resin which is cured by irradiating light in a visible light range to an ultraviolet light range and a wavelength within a range of about 800 nm to 200 nm. Photocurable resin is
It is composed of oligomers, monomers, photoinitiators and the like.
When the photoinitiator is irradiated with light, radicals and acids are generated, and a reaction occurs. Various structures of the oligomer and the monomer can be selected, and the terminal or the side chain has a functional group which reacts with a radical or an acid generated by the photoinitiator.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The members constituting the keypad of the present invention are cold-resistant,
Silicone rubber is preferred because of its excellent heat resistance, weather resistance, precision moldability, and electrical insulation. On the surface, a pattern in which letters, numbers, symbols, pictures, etc. are formed, or a pattern in which a light-shielding section is provided and letters, numbers, symbols, pictures, etc. are cut out may be formed. The silicone rubber of the keypad member has poor adhesion, but the surface of the resin keytop is modified by at least one of short-wavelength ultraviolet irradiation treatment, corona discharge treatment, flame treatment, plasma treatment, or primer treatment. It can be bonded firmly with a photocurable resin.

The resin key top of the present invention is a resin key top formed by die molding, a resin key top formed by cutting, a resin key top formed by stereolithography, and the like. For the molded resin key top, use a mold with the desired key top shape, and fill the mold with resin that has been heated and melted by injection molding, compression molding, transfer molding, rotational molding, etc. or liquid uncured resin. It can be manufactured by allowing it to solidify.

The composition, type, elastic modulus, and color tone of the resin key top are not particularly limited, but, for example, polycarbonate resin, polymethyl methacrylate resin, styrene resin, acrylic resin, polyolefin resin, ABS resin , A polyester resin, an epoxy resin, a polyurethane resin, a polyamide resin, a silicone resin, and the like. A design in which letters, numbers, symbols, pictures, and the like are formed on the front or back surface of the resin keytop, or a pattern in which a light-shielding portion is provided to cut out letters, numbers, symbols, pictures, etc., may be formed. These patterns may be provided with a coating layer.

A key top having a structure in which a film is integrally formed on the front and back surfaces of the resin constituting the key top, a key top having a design formed on the back and front surfaces of the film, and a design layer formed between the film and the resin. Key top,
The configuration of the resin keytop such as a plated keytop and a vaporized keytop is not limited. Also, the shape of the adhesive surface of the resin key top may not be flat, may be lightened in consideration of moldability and weight reduction, and may be formed with unevenness for positioning with the adherend. Absent.

[0012] Even if the resin key tops are independent of each other,
A configuration in which a plurality of the keypads are combined may be used, and the resin keytop may be connected to another adjacent resin keytop as long as the function and operation as the keypad are not hindered. A collar for preventing falling off and rotation may be formed on the outer peripheral portion. When illuminating the key top part, when making the pattern formed on the back of the key top visible through the resin key top, and when illuminating the design, the color tone of the resin key top is translucent It is necessary to

A silane coupling agent may be used as the silane compound of the present invention. Specifically, vinyl trichlorosilane, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl tris (β-methoxy ethoxy)
Methoxysilane, vinyltriacetoxysilane, vinyltriphenoxysilane, vinylmethyldichlorosilane,
Vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinyldimethylmethoxysilane, divinyldichlorosilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-gly And sidoxypropyltrimethoxysilane.

The photo-curable resin of the present invention includes various types such as those that cure with visible light and those that cure with ultraviolet light. Considering this, an ultraviolet curable resin is desirable.

The short-wavelength ultraviolet irradiation used in the manufacturing method of the present invention is to irradiate the surface of the keypad with the short-wavelength ultraviolet ray at a constant illuminance and a constant integrated light amount to modify the surface. More specifically, radiation of 184.9 nm and 253.7 nm emitted from a mercury lamp in which mercury is sealed at a pressure of about 10 ^-1 mmHg generates ozone in the presence of oxygen, and the ozone irradiates the surface of the non-treated body. It oxidizes to generate an active group such as a carboxyl group or a silanol group, thereby improving the adhesion and affinity of printing inks and paints.

In the corona discharge treatment, a high voltage is applied between the electrodes in the air to cause dielectric breakdown and discharge. During the discharge, the polymer on the surface layer is oxidized and the active group is formed on the surface. To bring about the same effect. In the flame treatment, the surface is oxidized and activated through a non-treated material in a strong oxidizing flame, and the same effect as the corona treatment is obtained. Plasma treatment is a process in which a glow discharge is generated in a low-pressure inert gas, oxygen, or halogen gas, thereby ionizing gas molecules to generate plasma, and using the chemical activity to activate the surface of the workpiece. Things. Irradiation treatment with short wavelength ultraviolet rays, corona discharge treatment, flame treatment, or plasma treatment is a dry process, so the process can be simplified as compared with the method using a surface treatment agent.However, plasma treatment requires a vacuum state and equipment is required. Since it is expensive and flame treatment involves danger, short wavelength ultraviolet irradiation treatment or corona discharge treatment is more desirable.

A photocurable resin containing a silane compound is applied to the surface treatment part of the keypad and / or the adhesive part of the resin keytop with the keypad, and the light is irradiated on the keypad and the resin keytop. And adhere. The method for adding the silane compound of the present invention is not particularly limited. When added to an uncured photocurable resin, it reacts with the photocurable resin simultaneously with the curing reaction. The silane coupling agent may be previously reacted with a compound constituting the photocurable resin, and then the photocurable resin may be cured.

When the photocurable resin is cured by irradiating light from the keypad side, at least the member of the keypad member on which the photocurable resin is applied is cured to a thickness of 200 to 800 nm where the applied photocurable resin is cured. It is necessary to be composed of a translucent or semi-transmissive member that transmits light having a wavelength in the range described above. When irradiating light from the keytop side, at least the member of the resin keytop member to which the photocurable resin is applied transmits light having a wavelength in the range of 200 to 800 nm where the applied photocurable resin is cured. It is necessary to be composed of a light-transmitting member.

When a light-transmitting resin is used as the photocurable resin containing a silane compound, and at least a part of the resin key top member is light-transmitting, characters formed on the surface of the keypad through these are used. Numbers, symbols, pictures, etc.
Naturally, a configuration in which the color tone and the like can be visually recognized is also considered.

The method of applying the photocurable resin containing a silane compound is not specified, such as a screen printing method, a dispenser method, a potting method, a pad printing method, a spray method, and a transfer method.

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples 1 to 4 As shown in FIG. 1, the surface of a keypad 1 formed using a translucent silicone rubber compound (SH851 manufactured by Dow Corning Toray Silicone Co., Ltd.) was modified by corona discharge treatment. Quality. Keypad 1
Of vinyltrimethoxysilane (Toray Dow Corning Silicone Co., Ltd. SZ630)
UV curable resin (3075 manufactured by Three Bond Co., Ltd.) to which 0) was added in the range of 0 to 25 parts by weight was applied as an adhesive 3 by a screen printing method, and Examples 1 to 4 and Comparative Examples 1 and 2 were prepared. Produced. A pattern printing 5 is performed on the back surface of the resin key top 4 formed of a translucent polycarbonate resin (Panlite L1225L manufactured by Teijin Chemicals Limited) with printing ink (Sericol 13 manufactured by Teikoku Ink Co., Ltd.)
The resin key top 4 was bonded to the key top bonding portion 2 and bonded by irradiating ultraviolet light from the key pad side. Table 1 shows the results.

Table 1 Comparison of moisture resistance of Examples 1 to 4 and Comparative Examples 1 and 2 Moisture resistance test conditions: 60 ° C, 95% relative humidity, continuous 240h Evaluation: Peel off the test piece and evaluate if silicone rubber or polycarbonate resin breaks down ○ Adhesive interface peeling or cohesive failure of adhesive × Table 1 As described above, the ultraviolet curable resin to which the silane compound of Comparative Example 1 was not added has insufficient moisture resistance. Further, if the amount of addition is too large as in Comparative Example 2, the strength of the adhesive is reduced, which is not preferable.

[0022]

Embodiment 5 As shown in FIG. 2, the surface of a keypad 1 formed using a translucent silicone rubber compound (SH851 manufactured by Dow Corning Toray Silicone Co., Ltd.) was exposed to a short-wavelength ultraviolet ray. Modified. Γ-methacryloxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)
An ultraviolet curable resin (3075 manufactured by Three Bond Co., Ltd.) to which 5 parts by weight of KBM502 was added was applied as an adhesive 3 by a dispenser. AB so that the back has a lightened structure
S resin (Diapet ABS manufactured by Mitsubishi Rayon Co., Ltd.)
The surface of the resin key top 4 molded in 3001) was coated with a urethane paint (Hi-Ulex P, manufactured by Musashi Paint Co., Ltd.), subjected to pattern printing 5, and laser cut to form letters. The resin key top 4 was bonded to the key top bonding portion 2 and bonded by irradiating ultraviolet light from the key pad side.

[0023]

Embodiment 6 As shown in FIG. 3, the surface of a keypad 1 formed using a translucent silicone rubber compound (SH851 manufactured by Dow Corning Toray Silicone Co., Ltd.) was surface-modified by corona discharge treatment. . A vinyl tris (β-methoxyethoxy) methoxysilane (KBC1 manufactured by Shin-Etsu Chemical Co., Ltd.)
003) was added as an adhesive 3 by a dispenser using an ultraviolet-curing resin (3075 manufactured by Three Bond Co., Ltd.) to which 5 parts by weight was added. A resin key top 4 molded with a polycarbonate resin (Panlite L1225L manufactured by Teijin Chemicals Ltd.) is attached to the key top bonding portion 2 so that the film 6 with the pattern printed 5 on the back surface is integrated with the front surface, and the key pad side Was irradiated with ultraviolet light to adhere.

[0024]

Example 7 As shown in FIG. 4, the surface of a keypad 1 molded using a translucent silicone rubber compound (SH851 manufactured by Dow Corning Toray Silicone Co., Ltd.) was irradiated with a short-wavelength ultraviolet ray. Modified. An ultraviolet curable resin (UV0114 manufactured by Epoxy Technology Co., Ltd.) to which 5 parts by weight of γ-glycidoxypropyltrimethoxysilane (SZ6040 manufactured by Dow Corning Toray Silicone Co., Ltd.) is added to the key top bonding portion 2 of the keypad 1. The adhesive 3 was applied by a screen printing method. Translucent polycarbonate resin (Panlite L1 manufactured by Teijin Chemicals Limited)
The surface of the resin key top 4 molded with 225L) is subjected to pattern printing 5 with printing ink (Sericol 13 manufactured by Teikoku Ink Co., Ltd.), and the resin key top 4 is attached to the key top bonding portion 2
, And bonded by irradiating ultraviolet light from the keypad side.

[0025]

Comparative Example 3 As shown in FIG. 5, the surface of a keypad 1 formed using a translucent silicone rubber compound (SH851 manufactured by Dow Corning Toray Silicone Co., Ltd.) was surface-modified by corona discharge treatment. . Vinyl trimethoxysilane is applied to the key top bonding portion 2 of the keypad 1 and then an ultraviolet curable resin (manufactured by Three Bond Co., Ltd.)
3075) was applied as an adhesive 3 by a screen printing method. Printing ink (Sericol, manufactured by Teikoku Ink Co., Ltd.) on the back surface of resin keytop 4 molded with translucent polycarbonate resin (Panlite L1225L, manufactured by Teijin Chemicals Ltd.)
In 13), a pattern printing 5 was performed, and the resin key top 4 was bonded to the key top bonding portion 2 and bonded by irradiating ultraviolet light from the keypad side.

Table 2 shows the results of Examples 5, 6, and 7 and Comparative Example 3.

[Table 2] Comparison of moisture resistance of samples of Examples and Comparative Examples Moisture resistance test conditions: 60 ° C, 95% relative humidity, continuous 240 h Evaluation: Peel off the test piece and evaluate if silicone rubber or polycarbonate resin breaks down ○ Adhesive interface peeling or breakage of adhesive × Table 2 As described above, the bonding strength of the resin key top of the key pad with the resin key top exemplified in Examples 5, 6, and 7 was good, and the moisture resistance was also good. However, in the keypad with the resin keytop of Comparative Example 3, although the moisture resistance was improved, the number of steps for applying the silane coupling agent increased, and the productivity was not sufficiently high.

As described above, according to the keypad with the resin keytop and the method of manufacturing the same of the present invention, the moisture resistance of the keypad with the resin keytop using a photocurable resin containing a silane compound is improved. By raising
There is an advantage that a keypad with higher reliability and higher productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of Examples 1 to 4 and Comparative Examples 1 and 2.

FIG. 2 is a longitudinal sectional view showing a configuration of a fifth embodiment.

FIG. 3 is a longitudinal sectional view showing a configuration of a sixth embodiment.

FIG. 4 is a longitudinal sectional view showing the configuration of a seventh embodiment.

FIG. 5 is a longitudinal sectional view showing the configuration of Comparative Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Keypad part 2 Key top adhesion part 3 Adhesive 4 Resin key top 5 Design printing 6 Film

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 2, 1999 (1999.4.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Embedded image (Wherein, R ₁ includes at least one functional group selected from a vinyl group, a methacryl group, an acryl group, or an epoxy group, and R ₂ is a chlorine group, an alkoxy group having 1 to 6 carbon atoms, 2-methoxy A functional group selected from an ethoxy group or an acetoxy group, R ₃ is a methyl group or an ethyl group,
When n is 1, m is 2 or 3, and when n is 2, m is 2.)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

On the other hand, silicone rubber is inherently poor in adhesiveness, and can be manufactured only by using a specific material and manufacturing method when manufacturing a type in which a resin key top of a bonded type is bonded. No high adhesive strength was obtained and the productivity was not high. However, a method has been proposed in which a silicone rubber is subjected to a surface treatment to obtain sufficient adhesive strength and to greatly improve the degree of freedom in materials and manufacturing methods (Japanese Patent Application No. 9-323932). Pads and resin key tops can be made stronger, and a resin with a low softening point, such as ABS resin, can be used. Also, bonding work can be performed quickly, and misalignment can occur during bonding. And a keypad with a resin keytop with high productivity can be manufactured.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

Among the proposals disclosed in Japanese Patent Application No. 9-323932, a photocurable resin is used as an adhesive for bonding a surface-treated silicone rubber and a resin keytop. The type is particularly effective because of its high workability and productivity. However, the type using the photo-curable resin is under high temperature and high humidity (60 ° C, relative humidity 95%, continuous 2
At 40 h), the adhesive durability (hereinafter, moisture resistance) was insufficient. As a countermeasure, a method of applying a primer such as a primer has been proposed in Japanese Patent Application No. 9-323932.
The application of such an undercoating agent not only increases the number of steps, but also has many problems such as dimensional changes due to the undercoating agent penetrating into silicone rubber and swelling, and the occurrence of an effective time of the undercoating agent. A highly productive photocurable resin adhesive has been desired.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) // C09J 183/04 C09J 183/04 F term (Reference) 4F071 AA01A AA01B AA50B AA67B AC16A AG15 AG16 AG17 AG30 AH16 CA08 CB01 CC04 CD03 4F073 AA01 BA33 BB08 CA01 CA21 CA45 GA03 4J040 HD32 HD35 JB08 KA13 LA07 MA10 MA11 MA12 PA15 5G006 AA01 CB05 CB09 JF02 5G023 AA12 CA19 CA24

Claims (3)

[Claims] An adhesive for bonding a silicone rubber keypad and a resin key top is bonded with an adhesive containing 0.1 to 20 parts by weight of a silane compound to 100 parts by weight of a photocurable resin. Keypad with resin key top. 2. The keypad with a resin keytop according to claim 1, wherein the silane compound is a compound represented by the following chemical formula (1). Embedded image (Wherein, R ₁ includes at least one functional group selected from a vinyl group, a methacryl group, an acryl group, or an epoxy group, and R ₂ is a chlorine group, an alkoxy group having 1 to 6 carbon atoms, 2-methoxy A functional group selected from an ethoxy group or an acetoxy group, R ₃ is a methyl group or an ethyl group,
When n is 1, m is 2 or 3, and when n is 2, m is 2.) 3. The surface of at least a part of the bonded portion of the silicone rubber keypad is modified by at least one method selected from a short wavelength ultraviolet irradiation treatment, a corona discharge treatment, a flame treatment, and a plasma treatment. A method for manufacturing a keypad with a resin keytop, wherein the pad and the resin keytop are bonded by the adhesive according to claim 1 or 2.