JP2005290283A - Silicone rubber composition, silicone rubber molded article and carrier plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-quality silicone rubber composition that can easily be produced, to provide a silicone rubber molded article and to provide a carrier plate. <P>SOLUTION: The silicone rubber composition is produced by adding 0.25-1 pts.wt. diacyl peroxide as a vulcanizing agent and 0.3-10 pts.wt. functional monomer to 100 pts.wt. thermosetting silicone rubber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-quality silicone rubber composition, a silicone rubber molded article, and a carrier plate.

  In general, silicone rubber is a material with excellent heat resistance and cold resistance, good compression recovery in a wide temperature range, and excellent weather resistance, ozone resistance, corona resistance, electrical characteristics, heat oil resistance, chemical resistance, etc. They are used in various industrial fields by taking advantage of these characteristics.

  For example, keyboard seals, rubber rollers, O-rings, packings for electric kettles, conveyor heater belts and other silicone rubber moldings that require dimensional accuracy, and oil seals that adhere silicone rubber to adherends such as metal fittings. It is used as a composite molded product such as a carrier plate.

  Here, the carrier plate is a jig used when a coating to be a terminal (electrode) is applied to an end portion of a chip-shaped small electronic component such as a multilayer ceramic capacitor. This carrier plate is known to have a configuration in which an electronic component support made of a rubber-like elastic body having a large number of elastic holes for supporting a large number of small electronic components is provided on the plate body (for example, a patent Reference 1).

  In other words, a large number of through passages are formed in the thickness direction of a metal rectangular plate body, and an elastic hole for supporting a small electronic component by an elastic member is provided on the inner wall surface of each passage. It is usually molded by transfer molding. Aluminum is often used for the plate body of this type of carrier plate, and silicone rubber is frequently used for the elastic member forming the electronic component support. The coating on the small electronic component is made by pressing the small electronic component, which is a chip component having an outer diameter larger than the inner diameter of the elastic hole, into the elastic hole of the carrier plate until the tip protrudes, and elastically gripping it. A terminal is formed by coating the protruding end with a conductive paste made of silver, palladium, or the like, followed by heat curing.

  The silicone rubber has various grades depending on its form and curing mechanism, and is roughly classified into a thermosetting silicone rubber and a liquid silicone rubber.

  Thermosetting silicone rubber is made of polyorganosiloxane, which is linear and has a high degree of polymerization, as a main raw material, and contains a silica-based reinforcing filler and various additives for imparting various properties to form a base compound. It is a type of rubber that is adjusted and then heat cured by adding a vulcanizing agent.

  This type of silicone rubber is widely used industrially because it can be handled in the same way as general organic rubber because it is molded through roll operations such as plasticization, vulcanizing agent blending, and sheeting. Millable silicone rubber Alternatively, it is also called a heat vulcanization type silicone rubber.

  In thermosetting silicone rubbers, it is common to use organic peroxides as vulcanizing agents, but the type and amount of organic peroxides are determined and used in a timely manner depending on the molding method and molding temperature. .

  Among thermosetting silicone rubbers using such organic peroxides, dicumyl peroxide or 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is generally used for compression molding and the like. However, the thermosetting silicone rubber compounded with these organic peroxides has a fairly high molding temperature of 160 to 180 ° C. In order to suppress the dimensional variation due to the rate, an organic peroxide having a decomposition temperature lower than that of dicumyl peroxide or 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is used. Molded at about 140 ° C.

  As such an organic peroxide for low-temperature vulcanization, a diacyl peroxide represented by 2,4-dichlorobenzoyl peroxide is generally used.

  However, when 2,4-dichlorobenzoyl peroxide is used as the organic peroxide for low-temperature vulcanization, it is known that a problem occurs that blooming occurs on the surface of the molded silicone rubber molded product ( For example, see Patent Document 2).

  In recent years, there has been a concern that a chlorine-containing diacyl peroxide such as 2,4-dichlorobenzoyl peroxide may be a minor by-product of polychlorinated biphenyl during use, and the industry has produced and produced 2,4-dichlorobenzoyl peroxide. It is known that it is in a movement to restrain its use (see, for example, Patent Document 3).

  Further, among diacyl peroxides, benzoyl peroxide hardly causes blooming and does not contain chlorine, so there is no fear of polychlorinated biphenyls as a byproduct.

Japanese Examined Patent Publication No. 62-11488 JP-A-6-65504 Japanese Patent No. 3299480

  By the way, in the prescription using the above-mentioned conventional benzoyl peroxide, although the occurrence of blooming can be prevented, there is a problem that the fused portion or the like turns brown. In particular, in a thick molded article or the like, it is remarkable that the fusion part or the like turns brown.

  The cause of this discoloration is that benzoic acid radicals or phenyl radicals generated from benzoyl peroxide are added to vinyl groups in the organopolysiloxane, and carbonization proceeds by newly generated polymer radicals, resulting in conjugated double bonds. It is estimated that.

  Therefore, there is a demand for a high-quality silicone rubber composition that does not turn blooming or brown, and a high-quality silicone rubber molded product obtained by molding this silicone rubber composition. In addition, products such as carrier plates using such high-quality silicone rubber molded products are also required to meet the recent demand for higher performance and higher quality.

  The present invention has been made in view of these points, and an object thereof is to provide a silicone rubber composition, a silicone rubber molded article, and a carrier plate that can easily achieve high quality.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that, in a silicone rubber composition, a diacyl peroxide and a functional polymer are used for a thermosetting silicone rubber, thereby producing a bloom or brown color. The inventors have found that discoloration can be prevented and have completed the present invention.

  That is, the silicone rubber composition according to the present invention is characterized by adding 0.25 to 1 part by weight of diacyl peroxide and 0.3 to 10 parts by weight of a functional monomer to 100 parts by weight of thermosetting silicone rubber. It is in the point.

  In the silicone rubber composition according to the present invention, the diacyl peroxide is preferably benzoyl peroxide.

  Furthermore, in the silicone rubber composition according to the present invention, the functional monomer is preferably a methacrylic acid ester.

  The methacrylic acid ester is preferably trimethylolpropane trimethacrylate or ethylene dimethacrylate.

  The silicone rubber molded product according to the present invention is characterized in that the silicone rubber composition according to any one of claims 1 to 4 is used.

  A feature of the carrier plate according to the present invention is that it is used when a terminal coating is applied to the end of a small electronic component, and the plate body has a rubber-like shape having a large number of elastic holes for supporting a large number of small electronic components. The carrier plate provided with the electronic component support made of an elastic body is characterized in that the electronic component support is the silicone rubber molded product according to claim 5.

  According to the silicone rubber composition, the silicone rubber molded product and the carrier plate of the present invention, there are extremely excellent effects such as high quality can be easily achieved.

  Hereinafter, the present invention will be described with reference to embodiments.

  As the thermosetting silicone rubber of the silicone rubber composition of the present invention, those that can be vulcanized with diacyl peroxide are used, including SH52U, SH831U, SH841U, SH851U, SH861U, SH871U, DY32-152U, DY32-305U, DY32. -310U, DY32-315U, DY32-337U, DY32-338U, DY32-339U, DY32-420U, DY32-421U, DY32-422U, DY32-433U, DY32-474U, DY32-475U, DY32-476U, DY32-522U , DY32-534U, DY32-540U, DY32-541U, DY32-542U, DY32-576U, DY32-580U, DY32-623U, DY32-638U, DY32 643U, DY32-645U, DY32-663U, DY32-800U, DY32-802U, DY32-803U, DY32-839U, DY32-903U, DY32-904U, DY32-910U, DY32-911U, DY32-912U, DY32-913U DY32-914U, DY32-915U, DY32-916U, DY32-922U, DY32-923U, DY32-924U, DY32-925U, DY32-926U, DY32-927U, DY32-931U, DY32-932U, DY32-932U, DY32-933U 934U, DY32-935U, DY32-936U, DY32-943U, DY32-946U, DY32-2007U (above, manufactured by Toray Dow Corning Silicone Co., Ltd.) ), KE152U, KE153U, KE167U, KE172U, KE174U, KE520U, KE530U, KE540U, KE550U, KE552U, KE552U, KE765U, KE785U, KE850U, KE870U, KE870U, KE870U, KE850U, KE850U, KE850U. KE7001U, KE7002U, KE7003U, KE7004U, KE7005U, KE7006U, KE7007U, KE7008U, KE7009U, KE7010U, KE7011U, KE70112U, KE7013U, KE7014U, KE7010U, KE7017U, KE7010U Top, trade name manufactured by Shin-Etsu Chemical Co., Ltd.), TSE221-3U, TSE221-4U, TSE221-5U, TSE221-6U, TSE221-7U, TSE221-8U, TSE270-4U, TSE270-5U, TSE270-6U, TSE270- Examples thereof include 8U, TSE2323-5U, TSE2323-6U, TSE2323-7U (trade name, manufactured by Toshiba Silicone Co., Ltd.) and the like.

  The hardness (rubber hardness) of such a thermosetting silicone rubber is not particularly limited, and may be arbitrarily selected from those in the range of 10 to 80 with a JIS A hardness meter after vulcanization, for example. However, the range of 30 to 65 is desirable from the viewpoint of balance between rubber hardness and mechanical properties.

  Examples of the diacyl peroxide used for vulcanization of the silicone rubber composition of the present invention include benzoyl peroxide, 2-methylbenzoyl peroxide, dimethylbenzoyl peroxide, trimethylbenzoyl peroxide, 4-methylbenzoyl peroxide, and the like. .

  As the diacyl peroxide, it is preferable to use benzoyl peroxide from the viewpoint of low decomposition temperature necessary for low temperature vulcanization for preventing blooming and obtaining dimensional stability, and 100 parts by weight of thermosetting silicone rubber On the other hand, the range of 0.25 to 1 part by weight, preferably 0.5 to 1.0 part by weight is optimal. If the amount is less than this range, compression set tends to be worse and vulcanization tends to be difficult. On the other hand, if the amount is more than this range, the vulcanization rate is not shortened due to the effect of increasing weight, and filling into silicone rubber becomes difficult. Workability at the time of kneading tends to be difficult.

  Examples of the functional monomer used in the silicone rubber composition of the present invention include dimethacrylic acid ester ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,6 dimethacrylic acid. -Hexanediol, polybutylene glycol dimethacrylate, or trimethylolpropane trimethacrylate which is a trimethacrylate ester.

  As the functional monomer, ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate is preferably used because of its good workability. The addition amount is optimally in the range of 0.3 to 10 parts by weight, preferably 0.3 to 3 parts by weight, and more preferably 0.5 to 1 part by weight with respect to 100 parts by weight of the thermosetting silicone rubber. is there. When the amount is less than this range, the effect of preventing discoloration is small, and when the functional monomer exceeds 10 parts by weight, discoloration does not occur but the hardness increases significantly.

  In the silicone rubber composition of the present invention, a hydrodiene polysiloxane may be added in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the thermosetting silicone rubber in order to shorten the vulcanization time. This includes KF99 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), SH1107 (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF484 (product name manufactured by GE Toshiba Silicone Co., Ltd.), etc. Can be illustrated.

  In the silicone rubber composition of the present invention, a plasticizer is added in the range of about 0.5 to 10 parts by weight with respect to 100 parts by weight of the thermosetting silicone rubber in order to plasticize the polymer and facilitate the molding operation. As plasticizers, KF96, KF96L, KF96H, KF965, KF968 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), SH200 (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF400, which are dimethyl silicone oils. , TSF401, TSF451, TSF456, TSF458, YF33 (above, product name manufactured by GE Toshiba Silicone Co., Ltd.), KF50, KF54, HIVAC F-4, HIVAC F-5, KF56 (above, Shin-Etsu Chemical) Product name), SH510, SH Examples include 550, SH704, SH705, SH710 (above, trade names manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF431, TSF433, TSF437, TSF4300 (above, trade names manufactured by GE Toshiba Silicone Co., Ltd.), and the like.

  In the silicone rubber composition of the present invention, conductivity may be imparted by adding a conductivity imparting agent, but conductive carbon black is unsuitable because it causes vulcanization hindrance in the presence of diacyl peroxide, It is necessary to use a conductivity-imparting agent other than conductive carbon black such as metal powder, metal oxide, and carbon fiber.

  In the silicone rubber composition of the present invention, the formulation of the filler for the silicone rubber is not particularly limited, and the mechanical properties of the cured rubber layer, that is, physical strength, rubber hardness, compression set, etc. This is determined in consideration of fumed silica such as Aerosil and Cab-O-Sil, wet silica such as Hi-Sil and Nipsil, diatomaceous earth such as Celite and Radiolite, Minusil And quartz powder such as crystallite are exemplified, and these fillers are usually used in combination of several kinds.

  In the silicone rubber composition of the present invention, aluminum oxide (alumina), titanium oxide, magnesium oxide, aluminum silicate, zinc oxide, iron oxide, calcium carbonate, or the like may be added to impart thermal conductivity.

  In the silicone rubber molded product of the present invention obtained by vulcanizing the silicone rubber composition of the present invention, dimensional accuracy is required to vulcanize the silicone rubber composition of the present invention at a low temperature of about 100 to 140 ° C. It is preferable in the sense that variation in the size of the product can be suppressed.

  In the carrier plate of the present invention, it is necessary to vulcanize and bond the silicone rubber composition of the present invention and the metal fitting. In this case, as an adhesive, for example, those used for conventional thermosetting silicone rubber, such as Chemlock 607, are used. Yachemok 608 (trade name, manufactured by Lord Corporation, USA), Sixson AN-187 and Sixson 304 (trade name, manufactured by Sixson Incorporated, USA), SH2260 primer and DY39-012 (products manufactured by Toray Dow Corning Silicone Co., Ltd.) Name), primer No. 8 and primer no. 16 and primer no. 18B (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) can be used. These adhesives can be used by diluting with alcohol, MEK, toluene or the like as necessary.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, this invention is not limited by this.

Example 1
100 parts by weight of KE951-U (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) as a thermosetting silicone rubber, C-1 (50% benzoyl peroxide-containing silicone paste) as a vulcanizing agent: Shin-Etsu Chemical 0.7 parts by weight), 0.3 parts by weight of acrylate ester TMP (trimethylolpropane trimethacrylate: trade name manufactured by Mitsubishi Rayon Co., Ltd.), which is a methacrylic ester as a functional monomer, and KE as a pigment -COLOR-W (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is weighed at a ratio of 1.0 part by weight (total 102.0 parts by weight), and each is kneaded with a well-known kneading roll. An unvulcanized rubber fabric was obtained.

Example 2
The blending ratio of the acrylate ester TMP of Example 1 was 0.5 parts by weight (total 102.2 parts by weight).

Example 3
The mixing ratio of the acrylate TMP of Example 1 was 1.0 part by weight (total 102.7 parts by weight).

Example 4
The blending ratio of the acrylate ester TMP of Example 1 was 2.0 parts by weight (total 103.7 parts by weight).

Example 5
The blending ratio of the acrylate ester TMP of Example 1 was 3.0 parts by weight (total 104.7 parts by weight).

Example 6
The blending ratio of the acrylate TMP of Example 1 was 5.0 parts by weight (total 104.7 parts by weight).

Example 7
The blending ratio of the acrylate TMP of Example 1 was 10.0 parts by weight (total 111.7 parts by weight).

Example 8
The acrylate ester TMP of Example 1 was changed to acrylate ester ED (ethylene glycol dimethacrylate: manufactured by Mitsubishi Rayon Co., Ltd.), and the blending ratio was 1.0 part by weight (total 102.7 parts by weight).

Comparative Example 1
The blending ratio of the acrylate TMP of Example 1 was 0 part by weight (total 101.7 parts by weight).

  Next, the unvulcanized rubber material, which is the silicone rubber composition of Examples 1 to 8 and Comparative Example 1, was vulcanized with a known vulcanization molding machine, and test pieces in accordance with JIS K 6251-6262. The rubber properties were evaluated and the presence or absence of discoloration was visually evaluated.

  Moreover, the carrier plate was formed using the rubber cloth of Example 1 to Example 8 and Comparative Example 1, and the presence or absence of occurrence of discoloration was visually evaluated.

  The carrier plate is manufactured by a process of injecting rubber dough into the aluminum plate in the mold by transfer molding, a process of heating the mold to 110 ° C. and performing vulcanization molding, and a step of obtaining the plate obtained by vulcanization molding. A finished product was obtained by performing a polishing process on each surface.

  Table 1 shows the blending ratios of the Examples and Comparative Examples and the test results.

  As shown in Table 1, in the molded silicone rubber products obtained by vulcanizing the silicone rubber compositions of Examples 1 to 8, the addition amount of acrylate TMP, which is a methacrylic ester as a functional monomer, increases. It was found that although the hardness increases somewhat, the occurrence of discoloration can be prevented.

  On the other hand, in Comparative Example 1, since no functional monomer was added at all, discoloration occurred at the rubber fabric fusion part. In particular, in the case of the carrier plate, due to the mold structure, the fusion of the rubber fabric entered from the injection port at the time of molding is most concentrated in the center of the product, so the central discoloration at the fusion part clearly appears.

  That is, it has been found that by adding a functional monomer, discoloration can be prevented and a uniform color tone can be obtained.

Further, it was confirmed by the blooming generation test that the sample pieces of each Example did not generate blooming even after 14 days.

Claims (6)

  A silicone rubber composition, wherein 0.25 to 1 part by weight of diacyl peroxide and 0.3 to 10 parts by weight of a functional monomer are added to 100 parts by weight of thermosetting silicone rubber.   The silicone rubber composition according to claim 1, wherein the diacyl peroxide is benzoyl peroxide.   The silicone rubber composition according to claim 1, wherein the functional monomer is a methacrylic acid ester.   The silicone rubber composition according to claim 3, wherein the methacrylic acid ester is trimethylolpropane trimethacrylate or ethylene dimethacrylate.   A silicone rubber molded article, wherein the silicone rubber composition according to any one of claims 1 to 4 is used. An electronic component support body made of a rubber-like elastic body having a large number of elastic holes for supporting a large number of small electronic components is provided in the plate body, which is used when a terminal coating is applied to the end of the small electronic component. In the carrier plate
The carrier plate, wherein the electronic component support is the silicone rubber molded product according to claim 5.