TW483832B - Silicone rubber composition for key pad and key pad made thereform - Google Patents

Abstract

The present invention is related to a rubber composition for use in a key pad, which is obtained by adding 0.1-100 pts wt. hollow filler having a mean particle diameter of less than 200 μm in 100 pts wt thermosetting organopolysiloxane composition, as well as, to a key pad made by said rubber composition, which is lightweight and has improved durability.

Description

Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs and the Consumer Consumption Monograph 483832 A7 ___B7__ V. Description of the Invention (!) Technical Field to which the Invention belongs The present invention relates to a computer keyboard, a remote control, a mobile phone, and other operation panels of a machine. Silicone rubber composition for key pads used for FF switches and key pads obtained thereby. Problems to be Solved by the Conventional Technology and Invention The heat-curable liquid silicone rubber composition is used in various fields because of its superior moldability, durability, heat resistance, and electrical insulation after molding. Among them, it is widely used in keyboard pads, keyboards, remote controllers, telephones and other key pad materials due to its durability (dynamic fatigue characteristics) and superior rebound characteristics. Machines using these keypads, such as notebook PCs or mobile phones, have increased portability, so they are required to be short and thin. However, the conventional silicone rubber key pads have a specific gravity of almost all above 1.0. For example, in order to reduce this specific gravity, there has been a conventional method of adding a thermally decomposable foaming agent or a lightweight silicone rubber foam (foam or sponge) to the material. A method of forming by using hydrogen produced as a by-product during curing. However, in the method of adding a thermal decomposition type foaming agent, the decomposition gas toxicity or odor is pointed to a problem, and the use of a platinum catalyst in the curing catalyst to use the curing barrier of the foaming agent is pointed to a problem. Furthermore, in the method using hydrogen produced as a by-product during curing, there are problems such as the explosive nature of hydrogen and the handling of uncured materials during storage. In addition, the formed product (sponge-like foam) is not uniform due to uneven air bubbles, and has insufficient strength. The durability of the material used as a key pad is inferior. The paper dimensions are subject to Chinese national standards (CNS). ) A4 size (210 X 297 mm) -4-W ------------------ Order --------- (Please read the precautions on the back first Fill out this page again) 483832 A7 ___ B7 V. Invention Description e) Exist. The present invention has been made in order to improve the above-mentioned problems, and has as its object to provide a silicone rubber composition for a key pad that can provide a light-weight and excellent durability key pad, and a key pad obtained by using the composition. Means taken to solve the problem and the embodiment of the invention As a result of careful review in order to achieve the above-mentioned object, the inventor found that the heat-curable organic polysiloxane composition (polysiloxane composition) was blended with an average Small hollow aggregates with a particle diameter of less than 2 0 // m. The cured silicone hardened product has a small specific gravity and excellent fatigue durability. As a material for key pads, the invention is completed. 〇 Accordingly, the present invention provides a hollow aggregate with an average particle diameter of 2 0 0 // m or less in a weight ratio of 100 to 10 parts by weight of the thermosetting organic polysiloxane composition. The keypad features a silicone rubber composition and a keypad. The present invention is described in further detail below. . Made by Qiu, a staff consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The silicone rubber composition for key pads of the present invention is made by mixing a hollow curable material with a thermosetting organic silicone composition. Here, as for the hollow material, it is a material having a gas portion in the cured product and reducing the thermal conductivity like rubber foam. Such materials include glass hollow balls, silicon dioxide hollow balls, carbon hollow balls, and phenol resin hollow. Balls, acrylonitrile hollow balls, vinylidene chloride hollow balls, alumina hollow balls, chromium dioxide hollow balls, silicon hollow balls, etc. may be used. Among these, the hollow paper material is used in the paper size of the Chinese National Standard (CNS) A4 (210 X 297 mm)-5-483832 A7 B7. 5. Description of the invention) Those with elasticity, that is, made of thermoplastic resin Hollow spheres, especially polymers of vinylidene chloride, acrylonitrile, methacrylonitrile, acrylates, methacrylates, or copolymers of two or more of these are more suitable. • For reasons such as the strength of hollow concrete, inorganic concrete and the like may be adhered to the surface. In this case, sufficient thermal conductivity is performed in the silicone rubber composition, and the true specific gravity of the hollow material is preferably 0 · 0 1 to 0.8, more preferably 0.01 to 0.5, and most preferably 0.02 to 0.5. . If the true specific gravity is too small, it will only be difficult to co-operate, or the compressive strength of the hollow concrete will not be sufficient, and it will be damaged during the forming process, failing to reduce the weight and reduce the thermal conductivity. In addition, if the specific gravity is large, the thickness of the shell of the hollow material becomes large, and a decrease in thermal conductivity may be insufficient.

Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs I. The average particle diameter of the hollow material is below 2 0 // m, preferably below 15 0 / zm, more preferably below 9 0 // m, average particle. If the diameter is too large, the hollow material will be damaged due to the injection pressure during molding, and the thermal conductivity will be increased. There will be problems such as the roughness of the surface of the key pad after forming will increase. The lower limit of the particle diameter is not particularly limited, but it is usually 10 // m, especially 20 // m, and the average particle diameter here is usually a weight average using laser light diffraction method (or Middle diameter). Furthermore, in the present invention, as for the hollow concrete, it is more effective that the elastic properties measured by the following method are 10% or more, preferably 15% or more. If the elastic characteristics are less than 10%, the hollow concrete itself is relatively hard, so it may not be possible to obtain sufficient impact absorption characteristics. In addition, the upper limit of this elastic characteristic is usually 50%, preferably 45%. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -6-Printed by the Employees' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 483832 A7 ~~ --SZ_ V. Description of the invention 4) Method for measuring elastic properties ： Elasticity refers to the range in which the hollow ball can be reversibly or repeatedly deformed without being damaged. It is measured as follows. Hollow aggregate and dimethyl silicone oil with a viscosity of 1000 c S (centimeter 'ceimstoke, the same below) at 25 ° c were mixed to a volume ratio of 50:50, and this was injected into a 5.0% (: syringe Within 3.0 (::, the tip is closed, and the deformation rate when a force of 20 kgf is applied is measured. For example, the deformation rate when 3 · cc becomes 2 · 4 c c is (1-2 · 4 / 3 · 0) xiq〇 = 20%. However, when the force of 20 kgf is removed, it must be restored to 3.0 cc. The amount of the above-mentioned hollow aggregate is 100 weight of the thermosetting organic polysiloxane composition. It is divided into 0.1 to 100 weight points, preferably 0.2 to 100 weight points, and more preferably 0.5 to 100 weight points. This case is a silicone rubber composition for a key pad of a hollow material. The content of 5% by volume is preferably 10 to 80%, and 15 to 75% is particularly suitable. If the volume ratio is too small, the reduction in thermal conductivity is not sufficient, and if it is too large, it is not only difficult. There are concerns about the formation of the molded product and the fragility of rubber elasticity. On the other hand, as for the thermosetting organopolysiloxane composition, The heat-curable organic polysiloxane composition of the known composition of the polysiloxane rubber layer of the pad may be either an organic peroxide hardened type or an addition reaction hardened type, but (A) contains at least one molecule Two suspected bases bonded to sand atoms are the paper size applicable to the Chinese National Standard (CNS) A4 (210 X 297 mm) ~~ -I —.1 I -------- i — — — — — — ^ «— — 1 —---- (Please read the notes on the back before filling in this page) 483832 Consumption Cooperation of Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs-Printed by the Press A7 _ B7____ V. Description of Invention §) 100 parts by weight of organic polysiloxane (B) Organic hydrodiene polysiloxane containing at least two hydrogen atoms bonded to silicon atoms in one molecule 0.1 to 50 parts by weight • (C) Addition reaction Addition reaction of catalyst amount as main component. Hardened organic polysiloxane composition is particularly suitable. Here, as for the component (A), organic polysilicon containing at least two alkenyl groups in one molecule. Oxane can be expressed by the following average composition formula (1)

RiaSi 〇 (4-a) / 2 (1) In the formula, R1 is an unsubstituted or substituted monovalent hydrocarbon group having the same or different carbon number 1 to 10, preferably 1 to 8, and a is 1.5 to 2 · 8, preferably 1 · 8 to 2.5, more preferably a positive number in the range of 1 · 9 5 to 2 · 0 5. The above-mentioned R1 represents an unsubstituted or substituted monovalent hydrocarbon group bonded to a silicon atom, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, third butyl, and pentyl. Alkyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl and other alkyl groups, phenyl, tolyl, xylyl, naphthyl and other aromatic groups, benzyl, phenethyl, phenylpropyl, etc. Aralkyl, vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, octenyl and other alkenyl groups, or part or all of the hydrogen atoms of these groups are Substituted by halogen atoms such as fluorine, chlorine, and bromine, and cyano, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) -8 _ — · ------------------ Order ------- -(Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 483832 A7 ____ B7 V. Invention Description $) In this case, at least two of R1 need to be alkenyl (with The number of carbon atoms is preferably 2 to 8 and more preferably 2 to 6). And the content of alkenyl group is 0 · 001 ~ 10 mol% in R1, and it is particularly preferable to set it to 0.001 ~ 5 mol%. This alkenyl group may be bonded to the terminal of the molecular chain, or to a sand atom in the middle of the molecular chain, or to both. The structure of this organic polysiloxane basically has a chain structure, but part of it has a columnar structure, and a ring structure may be used. As for the molecular weight, it is not particularly limited. Although it can be used from those with low viscosity to those with high viscosity and raw rubbery ones, the rubbery elastomer will be formed due to curing, so the viscosity at 25 ° C is more than 100 cp, usually 100 ~ 1,000, 000, more preferably 500 to 100,000. As for (B) an organohydrodiene polysiloxane containing at least two, preferably three or more silicon atoms, hydrogen atoms (that is, Si fluorenyl groups) bonded in one molecule, the following can be used: Expressed by the average composition formula (2). R 2 b He S i 〇 (4-b-〇) / 2 (2) (In the formula, R 2 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the same group as the above-mentioned R 1 , But it is preferably a group without an aliphatic unsaturated bond. In addition, b is 0 · 7 ~ 2 · 1, preferably 1 · 0 ~ 2 · 〇, (: is 0 · 〇〇1 ~ 1 · 〇5 , Preferably 0 · 01 ～ 1 · 0, and b + c is 0 · 8 ~ 3 · 0, preferably 1 · 0 ~ 2. 5 is a positive number) 〇 This organohydrodiene polysiloxane is in one molecule At least two, it is necessary to apply the Chinese National Standard (CNS) A4 specification (210 X 297 mm) for this paper size. 9-—------------------ Order- -------- (Please read the notes on the back before filling out this page) 483832 A7 B7 Employee Consumption of the Intellectual Property Bureau of the Ministry of Economic Affairs-printed by the company 5. Inventive Note f) is 2 ~ 100, more appropriate 3 to 50 silicon atoms are bonded to hydrogen atoms. As for such an organohydrodiene polysiloxane, two-terminal trimethylsiloxy-blocked methylhydrodiene polysiloxane and two-terminal trimethylsiloxy-blocked dimethylsiloxane can be cited. Alkane, methylhydrodiene siloxane copolymer, rain-terminated dimethylhydrodiene siloxane blocked dimethylpolysiloxane, two-terminal dimethylhydrodiene siloxane blocked dimethylsiloxane Alkane, methylhydrodiene siloxane copolymer, two-terminal trimethylsiloxy blocked methylhydrodiene siloxane, diphenylsiloxane copolymer, two-terminal trimethylsiloxy closed methacrylate Hydroxydiene siloxane, diphenyl siloxane, dimethyl siloxane copolymer, (CH3) 2HSi〇w2 unit and SiO4 / 2 unit copolymer, (CH3) 2HSi〇1 Copolymers of / 2 units and Sio4 / 2 units and (C6H5) Si03 / 2 units, (CHdsHSiCU / s units and (CH + SiOm and S0 02 units of copolymers, etc.). In addition, the organohydrodiene polysiloxane is preferably a liquid at normal temperature, and its viscosity at 25 ° C is from 0.1 to 1,000 cp, preferably from 0.1 to 500 cp, and particularly preferably from 0.5 to 300 cp. Of the silicon atom in the molecule Usually, it is 3 to 300, preferably 4 to 100. The compounding amount of the organohydrodiene polysiloxane of the component (B) mentioned above, and the organic polysiloxane of the component (A) The weight of the alkane 1 0.00 is 0.1 to 50 weight parts' preferably 0 · 3 to 30 weight parts. In this case, the hydrogen atom (that is, Si Η) which has been bonded to the silicon atom of the (B) component Based on the molar ratio of the alkenyl group bonded to the silicon atom contained in the component (A) to a molar ratio of 0.4 to 5 in the range of 0.8 to 2 mol / mol For the first reading

| 4 页 IIIIII 定 # This paper size applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm)-10-483832 Printed by the Consumers' Office of the Intellectual Property Bureau of the Ministry of Economic Affairs When the ear ratio is too small, the heat resistance of the oxygen rubber may cause a foaming noise caused by an toxic hydrogen reaction. (C) Addition of component (A) component and (B, but it is known that the platinum acid, chloroplatinic acid-based siloxane or acetylene alcohol can be used in accordance with the amount of rhodium complex and the like. Desirable curing A) component, with platinum content or 1, 0 0 0 P pm, and other components with the above-mentioned thermosetting properties, depending on the conductive agent, silicon-containing compound, carboxylate, etc. Salt, silylation reaction control agent, silicone oil and other internal release agents in the above-mentioned hollow rubber silicone rubber so-called key pads of the present invention need to be connected to the ON / OFF switch A7 B7, the crosslinking density becomes too low To the inferior effect of the hardened silicon, if there are too many cases, due to the problem of delamination, there is still a poor reaction catalyst that will give a bad effect on the heat resistance, which is used to promote the curing addition reaction of the aforementioned components. Matchmaker. Therefore, platinum or a platinum compound such as platinum black, a chlorohydrin modified product, a chlorinated platinum acid, a complex of an olefin aldehyde, and ethylene can be exemplified. Furthermore, the use of platinum group metal compounds is also mentioned. In addition, the addition speed may be appropriately increased or decreased, but generally, the amount of the platinum group metal such as rhodium is set to a range of 0.1 to 1 and preferably 1 to 2 0 0 p pm. Organic polysiloxane composition It is said that it can be hydrogen such as silicon dioxide fine particles, calcium carbonate-based oxygen-based resin, carbon black, conductive zinc oxide, gold nitrogen compounds, acetylene compounds, phosphorus compounds, tin compounds, mercury compounds, sulfur compounds, etc. , Iron oxide, hafnium oxide-based heat-resistant agent, dimethyl, tackifier, shaking modifier, etc. The thermosetting organic polysiloxane composition is compounded with the composition and is used as a key pad. And here The shape of the dome is not only able to achieve a straight effect, but also contains other rubber or resin. This paper applies the Chinese National Standard (CNS) A4 specification (210x297 mm) -11-III — — — — — — — — · 1111111 ^ 0 — — — — — — — (Please read the precautions on the back before filling out this page) V. Description of the invention The bonding or compounding of guima is used by the user, regardless of this situation. Necessarily in 1 0 0, and more preferably at 180 cure). Here, silicone rubber is cured), which is particularly suitable. And its lower limit 483832 Α7 Β7 is formed, or any combination with metal round top can be used to make full use of its lightweight. The related key pads are formed to cure the above silicone rubber, but the curing conditions are not particularly limited. 1 ~ 1 50 ° C for 10 minutes ~ 1 hour ~ 2 0 ° C for 2 ~ 4 hours and post-curing (post hardened product obtained from the above silicone rubber composition (poly specific gravity below 0.95, 0 · 90 or less is 0.2 or more, and 0.3 or more is particularly suitable for the following examples. Examples and comparative examples are shown to specifically illustrate the present invention, but the present invention is not limited by the following examples. In addition, the following examples indicate weight points. Also, "> 100% elongation fatigue life" in the examples indicates measurement results according to the following methods: 100% elongation fatigue life using a bending fatigue test Machine [manufactured by Toyo Seiki Co., Ltd.] and measured. The dumbbell-shaped test piece was tested using JI s K 6 3 0 1 No. 3 dumbbell-shaped test piece specified in sections 1, 3, and repeated at room temperature at 5 5 z 1 0 0% elongation, expressed as the number of times until it breaks. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) -12-Please read the notes on the back first

Page Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs-483832 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 ______ B7__ V. Description of the Invention (〇) i Example 1 The two terminals are dimethylethylene at room temperature Dimethylpolysiloxane (1) with a viscosity of 10,000 poise (25 t) based on siloxy-blocked silicon dioxide (1) 68 minutes • 'Surface area of 200 m2 / g of silicon dioxide (manufactured by Japan Aerosil Corporation) , Aerosil 200) 32 minutes, hexamethyldisilazane 5 minutes, divinyltetramethyldisilazane 0.5 minutes, 2.0 minutes of water 30 minutes after mixing, and the temperature was raised to 150 ° C Stirring was continued for 3 hours and cooling was performed to obtain a silicone rubber substrate. Dimethicone (1) was added to this silicone rubber substrate for 100 minutes, the specific gravity was 0.04, the average particle diameter was 4 0 // m, and the elasticity measured by the method described above was < Features &gt; It is made of 38% thermoplastic resin hollow material (Expancel), Expancel DE) 2 points (equivalent to about 30% by volume of the composition) is placed in a planetary mixer, and stirring is continued for 30 minutes After that, a cross-linking agent is further added to the methyl chain terminal and the side chain of the methyl hydrodiene polysiloxane (S)-(2) (polymerization degree 17.Si- Η amount 0.0060mol / g) 2.5 minutes, the ethynylcyclohexanol of the reaction control agent was 0.5 minutes, and stirring was continued for 15 minutes to obtain a silicone rubber composition. A lead catalyst (Pt concentration 1%) was mixed in this silicone composition with 0 · 1 minute, and then cured at 120 ° C / 10 minutes to obtain a 2 mm plate, and the specific gravity and hardness were measured. , 100% elongation fatigue life. The results are shown in Table 1. Example 2 · The dimethyl polysiloxane (1) 65 of Example 1 was taken at room temperature for 65 minutes. The paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm) ~ 13-&quot; Please read the back and face notes first

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483832 A7 ----- B7 V. Description of the invention (1) Silicon dioxide (specifically, Aerosil 300 manufactured by Japan Aerosil Corporation) with a specific surface area of 300m2 / g 35 minutes, hexamethyldisilazane 6 minutes, Divinyltetramethyldisilazane was mixed with 0.5 minutes of water and 2.0 minutes of water for 30 minutes, and then the temperature was raised to 150 ° C. The mixture was stirred for 3 hours and cooled to obtain a silicone rubber substrate. The silicone rubber base is added with dimethyl vinylsiloxy, which has two terminals terminated by dimethylvinyloxy, at a temperature of 25 ° C. ) 35 points, specific gravity 0 · 02, average particle size 9 0 // m, &lt; elasticity &gt; as measured by the method described above, 40% of a thermoplastic resin hollow material (manufactured by Matsumoto Oil & Fat Co., Microsphere F-80ED ) 1_ · 2 points (corresponding to about 33% by volume of the composition) put into the planetary mixer, continue stirring for 30 minutes, and then add a crosslinking agent to the two ends of the molecular chain and S i on the side chain -Methionyl methylhydrodiene polysiloxane (2) Polymerization degree 17, Si-Η Amount: 0.0060mo1 / g) 2.5 minutes, ethynylcyclohexanol of reaction control agent 0.05 minutes, continue Stir for 15 minutes to obtain a silicone rubber composition. A platinum catalyst is mixed in the silicone rubber composition (P t concentration 1%)

The Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed I 0 · 1 point, and it was cured at 120 ° C / 1.0 minutes to obtain a 2 mm plate, and the specific gravity and hardness were measured. The elongation fatigue life was 100%. . The results are shown in Table 1. Example 3 The dimethyl polysiloxane (1) of Example 1 at 70 minutes and a specific surface area of 300 m2 / g of silicon dioxide (Aerosil 300, manufactured by Japan Aerosil Corporation) at 30 minutes, Hexamethyldisilazane 5 points, Diethyl paper size Applicable to Chinese National Standard (CNS) A4 (210 X 297 mm) -14-483832 Intellectual Property Bureau, Ministry of Economic Affairs, Consumer Consumption-Printed by Izakusha A5 2. Description of the invention (2) Alkenyltetramethyldisilazane 0.5 minutes, water 2.0 minutes after mixing for 30 minutes, the temperature was raised to 150 ° C, and stirring was continued for 3 hours and cooled to obtain polysiloxane Rubber base. The dimethylpolysiloxane (3) of Example 2 was added to this polysiloxane rubber substrate for 100 minutes, and the specific gravity was 0.02, and the average particle diameter was 90 / m. &Lt; Elasticity &gt; A thermoplastic resin hollow material (manufactured by Matsumoto Grease Co., Ltd., Microsphere F-80ED) with a content of 40% is equivalent to about 3.0% (about 30% by volume of the composition is placed in a planetary mixer) Then, after stirring for 30 minutes, a cross-linking agent was added to the two terminals of the molecular chain and the methyl hydrodiene polysiloxane (S) having a Si-fluorenyl group on the side chain (degree of polymerization 17, Si- Amount of 0 · 0060 mol / g) 2 · 5 minutes, ethynyl cyclohexanol of the reaction control agent 0.5 · 5 minutes, and continued to stir for 15 minutes to obtain a silicone rubber composition. Here, the silicone rubber composition Mixed platinum catalyst (Pt concentration 1%) 0 · 1 minute, 2mm plate was obtained after curing at 120 ° C / 10 minutes, and specific gravity, hardness, and 100% elongation fatigue life were measured. The results are shown in Table 1. Example 4 The dimethylpolysiloxane (1) of Example 1 was obtained at room temperature for 65 minutes, and the specific surface area was 300 m2 / g of silicon dioxide (Aerosil, Japan). (Manufactured by the company, Aero sil 300) 35 minutes, hexamethyldisilazane 6 minutes, divinyltetramethyldisilazane 0.5 minutes, water 2.0 minutes after mixing for 30 minutes, and the temperature was raised to 150 ° C , Continue to stir for 3 hours and cool down to obtain a silicone rubber substrate. This silicone rubber substrate will be added within 100 minutes of this paper. The paper size applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). -15-(Please read the notes on the back before filling this page)

483832 A7 B7 V. Description of the invention &lt; 3) The dimethyl polysiloxane (1) of Example 1 30 minutes, specific gravity 0 · 22, average particle size 7 4 // m or less, measured by the above method &lt; Elastic characteristics> 2% glass hollow material (Sumitomo 3M, Scotchlite S22) Έ 5 minutes (equivalent to about 50% by volume of the composition) put in a planetary mixer, and after stirring for 30 minutes, A cross-linking agent is further added to the two terminals of the molecular chain and the methylhydrodiene polysiloxane having S i -fluorenyl groups on the side chains (2) (degree of polymerization 17, Si—fluorene amount 0.0060mol / g) 2 · 5 minutes, ethynylcyclohexanol of the reaction control agent 0 · 0 5 minutes, continue to stir for 15 minutes to obtain a silicone rubber composition, and the silicone rubber composition is mixed with a platinum catalyst t concentration of 1 %) 0 · 1 minute, 2 mm sheet was obtained by oven curing at 150 ° C / 1 hour, and the specific gravity and hardness were measured, and the fatigue life at 100% was extended. The results are shown in Table 1. Comparative Example 1 Sand dioxide of Example 1 = methyl polysiloxane (1) 6 8 and specific surface area of 200 m2 / g (made by Japan Aerosil Corporation, person 61: (^ 12 0) at room temperature 0) 2 points, 5 points for hexamethyldisarza nitrogen institute, 0 · 5 points for divinyltetramethyldisilazane, water, 2 · 0 points for mixing · After 30 minutes, warm up to 150 ° C , Continue to stir for 3 hours and cool down to obtain a silicone rubber substrate. Add dimethyl polysiloxane (1) to this silicone rubber substrate within 100 minutes and put it into the planetary mixer after 30 minutes After continuing stirring for 30 minutes, add methyl hydrodiene polysiloxane (S) with two terminals Si and fluorenyl on the side chain of the molecular chain (degree of polymerization 17 'Si, this standard applies to China) National Standard (CNS) A4 Specification (210 X 297 mm 1 ~ -16- (Please read the precautions on the back first ---- IIII ^-— — — — — — 1 — · This page)

Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs I 483832 A7-B7 V. Description of the invention (K) Amount ο · 〇〇〇〇〇〇ηη1 / g) 2 · 5 minutes, the reaction control agent acetylene cyclohexyl The alcohol was 0.55 minutes, and stirring was continued for 15 minutes to obtain a silicone rubber composition. A platinum catalyst (P • t concentration of 1%) was mixed in the silicone rubber composition 〇 · 1 minute, and a 2 mm plate was obtained by press curing at 120 ° C / 10 minutes, and the specific gravity, Hardness, 100% elongation fatigue life. The results are shown in Table 1.

Comparative Example 2 The dimethyl polysiloxane (1) of Example 1 was 100 minutes, quartz powder (Cystalite VX-ST) was _50 minutes, and the surface was hydrophobized silicon dioxide (manufactured by Japan Aerosil Corporation). , Aerosil R-9 7 2) Put into the planetary mixer and stir for 30 minutes, then add the following formula (3) [Chemical formula 1] ch3 h ch3

III CH3-Si〇- (Si-0) 20 Si-CH3 (3) CH3 ch3 ch3 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs-7 points of organohydrodiene siloxane indicated, and then added to the terminal is hydroxydi Methylsiloxy blocked formula (4) CH3 (4)

HO-f Si-O- ^ H CH, 6 minutes for dimethylsilane, 0.1% for ethynylcyclohexanol, and continue mixing for 15 minutes. Add 0.5% of 1% isopropyl alcohol solution of chloroplatinic acid to this silicone rubber composition. After stirring and defoaming, the paper size will be in accordance with China National Standard (CNS) A4. (210 X 297 mm) -17 _ 483832 A7 B7 V. Description of the invention 0 5) ° 〇 Foamed into a sponge shape in an oven and cut into a sheet thickness of 2 mm by the cured person, and measured the specific gravity, Hardness, 100% elongation fatigue life. The results are shown in Table 1. [Table 1] Example Example Example Example Comparative Example Comparative Example 1 2 3 4 1 2 Specific gravity (25) ° C 0.72 0.83 0.61 0,65 1.07 0.62 Hardness (JISA) 40 43 39 50 39 32 100% fatigue fatigue 609,000-104,400,123,230, 25,000 labor-life (times) The effect of the invention According to the invention, a light-weight and durable keypad can be obtained (please read the precautions on the back before filling this page) Consumption Cooperation of Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs--printed by Zuosha Co., Ltd. This paper applies Chinese National Standard (CNS) A4 (210 X 297 mm) 18-

Claims (1)

483832 public a A8 B8 C8 D8 VI. Application for patents Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs1. A press (A) on a molecular machine polysand oxygen institute (B) on a molecular organohydrodiene polysilicon ( C) In the thermoset formed by the addition reaction as the main component, the true specific gravity is 0.5%. 2. If you apply for a finished product, which is hardened 3. If you apply for an oxygen rubber composition, 4 · One according to any of the items in accordance with the patent application No. 881 1 5237 Chinese amendments to the scope of the patent application in China Silicone rubber composition for pad, which is characterized in that it contains at least two alkenyl groups bonded to silicon atoms, and contains at least two hydrogen atoms bonded to silicon atoms in an amount of 0.1 to 0.1% by weight. 50% by weight catalyst catalyst quantitative organic polysiloxane composition (average particle diameter of polysiloxane rubber group 2 0 0 // m below hollow material below 0.1% by weight of hollow material and patent scope The specific gravity of the silicone rubber composition for the keypad of the first item is 0.95 or less. The elastic properties of the hollow silicone material of the polysilicon for the keypad of the patent item 1 or 2 are more than 10%. Key pads are cured products with silicone rubber composition for key pads Nos. 1 to 3. (Please read the precautions on the back before filling out this page) This paper size applies to Chinese National Standards (CNS) A4 specifications (210X297 mm)