JP2000319513A - Filler for reinforcing silicone rubber - Google Patents
Filler for reinforcing silicone rubberInfo
- Publication number
- JP2000319513A JP2000319513A JP11131568A JP13156899A JP2000319513A JP 2000319513 A JP2000319513 A JP 2000319513A JP 11131568 A JP11131568 A JP 11131568A JP 13156899 A JP13156899 A JP 13156899A JP 2000319513 A JP2000319513 A JP 2000319513A
- Authority
- JP
- Japan
- Prior art keywords
- reaction
- surface area
- specific surface
- precipitated
- silicic acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、シリコーンゴム用
の補強剤として従来の沈澱珪酸が有する特性をそのまま
維持し、かつ繰り返し荷重などの動的疲労に対する耐久
性を向上させた沈澱珪酸からなるシリコーンゴム補強充
填剤に関する。BACKGROUND OF THE INVENTION The present invention relates to a silicone comprising a precipitated silicic acid as a reinforcing agent for silicone rubber, which maintains the properties of conventional precipitated silicic acid as it is and has improved durability against dynamic fatigue such as repeated loading. It relates to a rubber reinforcing filler.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】沈澱珪
酸は通常湿式法により製造され、乾式法の無水ケイ酸と
共に一般にホワイトカーボン又はシリカとも呼ばれてい
る。沈澱珪酸は、カーボンブラックに匹敵する性能を有
する白色のゴム補強充填剤として用いられている以外
に、農薬用坦体、分散剤、或は塗料、インク、接着剤、
更には製紙等の充填、コーテイング剤としても多岐分野
に使用されている。BACKGROUND OF THE INVENTION Precipitated silicic acid is usually produced by a wet process and is commonly referred to as white carbon or silica along with dry process silicic anhydride. Precipitated silicic acid is used as a white rubber reinforcing filler having performance comparable to carbon black, as well as pesticide carriers, dispersants, or paints, inks, adhesives,
Further, it is used in various fields as a filling and coating agent for papermaking and the like.
【０００３】また、最近では、優れた弾性（クリック特
性）と良好な圧縮永久歪を与えることから、キーボード
材（ラバーコンタクト）、自動車用ジョイントブーツ、
ダイヤフラム材などに好適とされるシリコーンゴムの補
強充填剤としても汎用されている。しかし、シリコーン
ゴムの補強充填剤として要求される物性は年々厳しくな
っている。特に、動的疲労特性に関しては電卓やパソコ
ン等の急速な伸びとともに、より高い性能を発揮するこ
とが要求されている。In recent years, keyboard materials (rubber contacts), automotive joint boots, and the like have been recently developed because of their excellent elasticity (click characteristics) and good compression set.
It is also widely used as a reinforcing filler for silicone rubber, which is suitable for diaphragm materials and the like. However, the physical properties required as a reinforcing filler for silicone rubber are becoming stricter year by year. In particular, with respect to dynamic fatigue characteristics, it is required that a calculator, a personal computer, and the like be rapidly evolved and exhibit higher performance.
【０００４】一般的に、シリコーンゴムは、グリーン強
度が弱い（即ち、ゴム自体の補強性能が弱い）。そのた
め、シリコーンゴム用補強充填剤は、他の有機ゴム用の
補強充填剤よりも、ゴム中での分散性に優れ、しかも補
強性能が高いことが望まれる。補強性能が高くても、ゴ
ム中での分散性に劣ると、結果として高い補強性能は得
られない。このような観点から、シリコーンゴム用補強
充填剤として用いられる沈澱珪酸としては、補強性能を
高めるために比表面積が大きく（即ち、一次粒子が細か
い）、かつ良好な分散性を有するものが必要とされる。
しかしながら、一次粒子を小さくして比表面積を大きく
すると、一般に、沈澱珪酸は凝集性が強くなる傾向があ
る。凝集性が強くなれば、分散性は低下する。比表面積
が大きく凝集性が強い沈澱珪酸の分散性を向上させるに
は、一次粒子の凝集体である二次粒子を機械的に小さく
する（粉砕する）必要がある。しかし、粉砕により微粉
化すると、見掛けの嵩比重が低くなり、作業性を悪化さ
せる要因になってしまう。又、分散性を重視するあまり
に比表面積を小さくする（一次粒子を大きくする）と、
最終ゴム製品としての強度が保てなくなってします。[0004] In general, silicone rubber has low green strength (that is, the rubber itself has low reinforcing performance). Therefore, it is desired that the reinforcing filler for silicone rubber has better dispersibility in rubber and higher reinforcing performance than the reinforcing filler for other organic rubbers. Even if the reinforcing performance is high, if the dispersibility in rubber is poor, high reinforcing performance cannot be obtained as a result. From such a viewpoint, precipitated silica used as a reinforcing filler for silicone rubber needs to have a large specific surface area (that is, fine primary particles) and have good dispersibility in order to enhance reinforcing performance. Is done.
However, when the primary particles are made smaller and the specific surface area is made larger, the precipitated silica generally tends to have higher cohesiveness. As the cohesion increases, the dispersibility decreases. In order to improve the dispersibility of precipitated silicic acid having a large specific surface area and strong cohesiveness, it is necessary to mechanically reduce (pulverize) secondary particles which are aggregates of primary particles. However, when the powder is pulverized by pulverization, the apparent bulk specific gravity becomes low, which is a factor of deteriorating workability. Also, if the specific surface area is too small to emphasize the dispersibility (increase the primary particles),
The strength as a final rubber product cannot be maintained.
【０００５】沈澱珪酸を補強充填剤として含有させた、
動的疲労耐久性を改善したシリコーンゴム組成物がこれ
までも知られている。特公平７−９１４６３号には、比
表面積が１００m2/g以上で、二次粒子の平均粒子径が５
μｍ以下の沈澱珪酸を用いたシリコーンゴム組成物が開
示されている。また、特開平９−３０２２３０号には、
比表面積が１００m2/g以上で、二次粒子の平均粒子径が
１０μｍ以下であり、かつ粒径１６μｍ以上の粗粒子が
シリカ全体の１５重量％以下である沈澱珪酸を用いたシ
リコーンゴム組成物が開示されている。これらのシリコ
ーンゴム組成物では、沈澱珪酸の粒子径を制御すること
で分散性を向上させ、その結果として、動的疲労耐久性
を改善している。特開平９−３０２２３０号には、標準
的な製造方法により得られた凝集シリカを粉砕分級する
ことで、所望の沈澱珪酸が得られると記載されている。[0005] precipitated silica was included as a reinforcing filler,
Silicone rubber compositions having improved dynamic fatigue durability have been known. Japanese Patent Publication No. Hei 7-91463 discloses that the specific surface area is 100 m 2 / g or more and the average particle diameter of
A silicone rubber composition using precipitated silicic acid having a particle size of not more than μm is disclosed. Also, JP-A-9-302230 discloses that
Silicone rubber composition using a precipitated silica having a specific surface area of 100 m 2 / g or more, secondary particles having an average particle diameter of 10 μm or less, and coarse particles having a particle diameter of 16 μm or more and 15% by weight or less of the entire silica. Is disclosed. In these silicone rubber compositions, the dispersibility is improved by controlling the particle size of the precipitated silicic acid, and as a result, the dynamic fatigue durability is improved. JP-A-9-302230 describes that a desired precipitated silicic acid can be obtained by pulverizing and classifying aggregated silica obtained by a standard production method.
【０００６】しかるに、上記のような粒子径のみを制御
した沈澱珪酸では、近年益々厳しくなっている物性要求
に応じられないのが現状である。そこで、沈澱珪酸が本
来有する物性を損なうことなく、動的疲労耐久性をより
向上させた、シリコーンゴム補強充填用の沈澱珪酸の出
現が望まれている。However, the precipitated silica in which only the particle size is controlled as described above cannot meet the increasingly severe physical property requirements in recent years. Therefore, there is a demand for the appearance of precipitated silica for reinforcing and filling silicone rubber, which has improved dynamic fatigue durability without impairing the intrinsic properties of precipitated silica.
【０００７】そこで本発明の目的は作業性、分散性に優
れ、動的疲労特性が飛躍的に向上したシリコーンゴム用
補強充填剤に適した沈澱珪酸を提供することにある。Accordingly, an object of the present invention is to provide a precipitated silicic acid which is excellent in workability and dispersibility and has a remarkably improved dynamic fatigue property and is suitable for a reinforcing filler for silicone rubber.
【０００８】沈澱珪酸は、ケイ酸アルカリ水溶液と鉱酸
とを中和反応させて、シリカ成分を反応液中で析出させ
ることにより得られる。析出した微細な沈澱珪酸を含む
反応懸濁液を濾過し、水洗して沈澱珪酸ケーキを得、さ
らにこれを乾燥、粉砕、必要に応じて分級することで、
沈澱珪酸は製造される。沈澱珪酸を構成する一次粒子同
士の結合・凝集状態は、ケイ酸アルカリ水溶液と鉱酸の
反応時間、反応温度、中和反応条件の違いや粉砕、分級
条件の違い等により変化する。従って、製造条件を微妙
に変化させることで、内部構造及び表面状態が異なる沈
澱珪酸が得られ、それぞれ異なった物性を示す。また、
沈澱珪酸のちょっとした物性の違いが、シリコーンゴム
に配合した場合に大きな影響を与える場合もある。本発
明では、粒子径のみを制御するのではなく、沈澱珪酸の
有するその他の物性も含めて、上記本発明の目的を達成
し得る沈澱珪酸を探索し、シリコーンゴム用の補強充填
剤として極めて有用な沈澱珪酸を見いだし、本発明を完
成させた。The precipitated silicic acid is obtained by neutralizing an aqueous alkali silicate solution with a mineral acid to precipitate a silica component in a reaction solution. The reaction suspension containing the precipitated fine precipitated silicic acid was filtered, washed with water to obtain a precipitated silicic acid cake, and further dried, pulverized, and classified if necessary.
Precipitated silicic acid is produced. The bonding / aggregation state of the primary particles constituting the precipitated silicic acid changes depending on the reaction time of the aqueous alkali silicate solution and the mineral acid, the reaction temperature, the difference in neutralization reaction conditions, the difference in pulverization and classification conditions, and the like. Therefore, by slightly changing the production conditions, precipitated silicas having different internal structures and surface conditions can be obtained, and exhibit different physical properties. Also,
A slight difference in the physical properties of precipitated silica may have a significant effect when blended with silicone rubber. In the present invention, not only controlling the particle size, but also searching for precipitated silicic acid that can achieve the object of the present invention, including other physical properties of precipitated silicic acid, is extremely useful as a reinforcing filler for silicone rubber. The present invention was completed by finding a precipitated silica.
【０００９】[0009]
【課題を解決するための手段】本発明は、吸油量が２０
０ ｃｃ/100g以下であり、ＢＥＴ法比表面積が１２０
〜２００m2/gの範囲であり、シアーズ滴定量（Ｖｍｌ）
とＢＥＴ比表面積（ｍ 2／ｇ）との関係式Ｖ（ＮａＯＨ
滴定量）ｍｌ＝1.5/100×ＢＥＴ(m2/g)＋Ｃにおける、
Ｃの値が０〜４の範囲であり、且つＮ2法で測定した細
孔直径のピーク位置Ａ（A）と水銀法で測定した細孔直
径のピーク位置Ｂ（A）との比Ａ／Ｂが１．４以上であ
る沈澱珪酸からなることを特徴とするシリコーンゴム補
強充填剤に関する。本発明の補強充填剤においては、吸
油量が１２０ ｃｃ/100g以上、１８０ｃｃ/100g以下の
範囲であること、Ｃの値が２．０以上、４以下の範囲で
あること、及び比Ａ／Ｂが１．５以上、２．０以下の範
囲であることが好ましい。According to the present invention, the oil absorption is 20
0 cc / 100 g or less, and the BET specific surface area is 120
~ 200mTwo/ g range, Sears titer (Vml)
And BET specific surface area (m Two/ G) and V (NaOH
Titer) ml = 1.5 / 100 × BET (mTwo/ g) + C
C is in the range of 0 to 4 and NTwoMethod
Peak position A (A) of pore diameter and pore diameter measured by mercury method
The ratio A / B to the diameter peak position B (A) is 1.4 or more.
Silicone rubber supplements comprising precipitated silica
Related to strong fillers. In the reinforcing filler of the present invention,
Oil amount of 120cc / 100g or more, 180cc / 100g or less
In the range, the value of C is 2.0 or more and 4 or less.
And the ratio A / B is in the range of 1.5 or more and 2.0 or less.
It is preferred that it is an enclosure.
【００１０】[0010]
【発明の実施の形態】本発明の沈澱珪酸は、吸油量が２
００ ｃｃ/100g以下である。吸油量は、好ましくは、
１２０ ｃｃ/100g以上、１８０ ｃｃ/100g以下の範囲
である。一般にシリカはその性質上、通常は200〜300
ｃｃ/100gと高い吸油量を保持している。それ故、その
特異性を利用して塗料、農薬分野等に実用されている。
しかし、吸油量が２００ｃｃ／１００ｇを超える沈澱珪
酸をシリコーンゴムの補強充填剤として用いると、シリ
コーンゴムへの混練時喰い込み性が悪くなると同時に、
ムーニー粘度が高くなり、又飛散しやすい粉体となり作
業性、生産性も悪くなる。そこで、本発明の補強充填剤
では、沈澱珪酸の吸油量は２００ ｃｃ/100g以下とす
る。このような観点から、好ましくは、吸油量は１８０
ｃｃ/100g以下である。一方、吸油量が低くなると、
補強効果が低下する傾向があるので、好ましくは、吸油
量は１２０ ｃｃ/100g以上である。BEST MODE FOR CARRYING OUT THE INVENTION The precipitated silica of the present invention has an oil absorption of 2
It is less than 00 cc / 100g. The oil absorption is preferably
The range is from 120 cc / 100g to 180 cc / 100g. Generally, silica is usually 200 to 300 in nature.
Has a high oil absorption of cc / 100g. Therefore, it is put to practical use in the fields of paints, agricultural chemicals, etc. by utilizing its specificity.
However, when precipitated silica having an oil absorption of more than 200 cc / 100 g is used as a reinforcing filler for the silicone rubber, the biteability during kneading into the silicone rubber deteriorates, and at the same time,
The Mooney viscosity becomes high, and the powder becomes easily scattered, resulting in poor workability and productivity. Therefore, in the reinforcing filler of the present invention, the oil absorption of precipitated silica is set to 200 cc / 100 g or less. From such a viewpoint, preferably, the oil absorption is 180
It is less than cc / 100g. On the other hand, when the oil absorption decreases,
Preferably, the oil absorption is 120 cc / 100 g or more because the reinforcing effect tends to decrease.
【００１１】本発明の沈澱珪酸は、上述のように吸油量
が比較的低い部類に属するものであるが、吸油量が低い
ということは、弱い外力で壊れ易い構造性を持ったもの
であるとも推察できる。すなわち、グリーン強度の低い
シリコーンゴムでも良分散が可能となっていることが想
像される。しかしながら、吸油量が低過ぎる場合シリカ
の粒度が粗くなったり、BETが極端に低い場合も吸油量
が低くなる。そこで、補強性能との良好なバランスが得
られるという観点から、本発明の沈澱珪酸の吸油量は、
１３０〜１８０ｃｃ/100gの範囲であることが最も好ま
しい。The precipitated silicic acid of the present invention belongs to a class having a relatively low oil absorption as described above. However, the low oil absorption means that the precipitated silica has a structure easily broken by a weak external force. Can be inferred. That is, it is conceivable that good dispersion is possible even with silicone rubber having low green strength. However, when the oil absorption is too low, the particle size of the silica becomes coarse, and when the BET is extremely low, the oil absorption also becomes low. Therefore, from the viewpoint of obtaining a good balance with the reinforcing performance, the oil absorption of the precipitated silica of the present invention is:
Most preferably, it is in the range of 130 to 180 cc / 100 g.
【００１２】本発明の沈澱珪酸は、ＢＥＴ法比表面積が
１２０〜２００m2/gの範囲である。ＢＥＴ法比表面積
は、好ましくは１３０〜１８０ｍ2／ｇの範囲である。
ＢＥＴ法比表面積が１２０ｍ2／ｇ以下ではゴム補強効
果が劣り、動的疲労耐久性や引張強度が低下する。一
方、２００ｍ2／ｇを越えると架橋密度が低下し、沈澱
珪酸の凝集力が強固すぎるために分散不良を起こたり、
又加工性も悪なる。さらには、応力集中への依存度が高
くなり動的疲労耐久性も低下する場合がある。The precipitated silica of the present invention has a BET specific surface area of 120 to 200 m 2 / g. The BET specific surface area is preferably in the range of 130 to 180 m 2 / g.
When the BET specific surface area is 120 m 2 / g or less, the rubber reinforcing effect is poor, and the dynamic fatigue durability and tensile strength are reduced. On the other hand, if it exceeds 200 m 2 / g, the crosslinking density decreases, and the cohesive force of precipitated silica is too strong, resulting in poor dispersion,
Also, the workability deteriorates. Further, the degree of dependence on stress concentration may increase, and the dynamic fatigue durability may decrease.
【００１３】本発明の沈澱珪酸は、シアーズ滴定量（Ｖ
ｍｌ）とＢＥＴ比表面積（ｍ2／ｇ）との関係式Ｖ（Ｎ
ａＯＨ滴定量）ｍｌ＝1.5/100×ＢＥＴ(m2/g)＋Ｃにお
ける、Ｃの値が０〜４の範囲である。シアーズ滴定量
（Ｖｍｌ）は、沈澱珪酸の表面シラノール基の密度を表
す指標として知られている。この表面シラノール基密度
指標であるシアーズ滴定量と、細孔分布などの粒子構造
の指標であるＢＥＴ比表面積について調査した結果、上
記関係式においてＣの値が一定の範囲にある場合、引張
強度や動的疲労耐久性が改善されることが判明した。こ
のＣの値が０より小さくても、４より大きくても、所望
の動的疲労耐久性等の改善が得られない。Ｃの値は、好
ましくは２〜４の範囲である。一般的にＢＥＴ比表面積
が高くなるとシラノール基量が多くなり、シアーズ滴定
量（Ｖ）も多くなる。しかし、Ｃの値を０〜４にするこ
とにより、余分なシラノール基を少なくしシリカ同士の
自己凝集が押さえられて、シリコーンゴムでのシリカの
分散が容易になるものと推察される。The precipitated silicic acid of the present invention can be used in a sears titration (V
ml) and the BET specific surface area (m 2 / g).
aOH titer) ml = 1.5 / 100 × BET (m 2 / g) + C, the value of C is in the range of 0 to 4. Sears titration (Vml) is known as an index representing the density of surface silanol groups of precipitated silica. As a result of investigating the BET specific surface area, which is an index of particle structure such as pore distribution, as a result of Sears titration, which is an index of surface silanol group density, when the value of C in the above relational expression is within a certain range, the tensile strength and It has been found that the dynamic fatigue durability is improved. If the value of C is smaller than 0 or larger than 4, a desired improvement in dynamic fatigue durability or the like cannot be obtained. The value of C preferably ranges from 2 to 4. In general, as the BET specific surface area increases, the amount of silanol groups increases, and the Sears titer (V) also increases. However, when the value of C is set to 0 to 4, it is presumed that excess silanol groups are reduced, self-aggregation between silicas is suppressed, and silica is easily dispersed in the silicone rubber.
【００１４】本発明の沈澱珪酸は、Ｎ2法で測定した細
孔直径のピーク位置Ａ（A）と水銀法で測定した細孔直
径のピーク位置Ｂ（A）との比Ａ／Ｂが１．４以上であ
る。一般に沈澱珪酸の細孔ピーク値は水銀圧入法により
測定した値（Ｂ）に比べ、Ｎ2吸着法により測定した値
（Ａ）の方が大きくなる傾向がある。これは、水銀圧入
法では、細孔分布測定時に圧力による沈澱珪酸粒子の圧
壊が起こり、微細孔部分が残存することで、見掛け上細
孔ピーク位置の違いが生じるものと考えられている。粒
子の圧壊の起こりやすい沈澱珪酸は、粒子の構造強度が
弱く、ゴム中への分散も良好であろうと予想され、実際
にもそのような傾向がある。比Ａ／Ｂが１．４未満の沈
澱珪酸では、粒子構造が強く、水銀法による水銀圧入時
に二次粒子以下への破壊進行が少なく、ゴム中において
も分散が困難となり、強度が不十分となる。但し、ＢＥ
Ｔ比表面積の高い（200m2/gを超える）沈澱珪酸でも同
様に、上記傾向が見られる。しかし、ＢＥＴ比表面積が
200m2/gを超えて高くなると、粒子同士の凝集性が強く
なり、分散不良が生じるため好ましくない。比Ａ／Ｂ
は、１．５以上、２．０以下の範囲であることが好まし
い。The precipitated silica of the present invention has a ratio A / B between the peak position A (A) of the pore diameter measured by the N 2 method and the peak position B (A) of the pore diameter measured by the mercury method is 1 .4 or more. Generally, the pore peak value of precipitated silica tends to be larger in the value (A) measured by the N 2 adsorption method than in the value (B) measured by the mercury intrusion method. It is considered that in the mercury intrusion method, the precipitated silica particles are crushed by pressure during the measurement of the pore distribution, and the fine pore portion remains, which apparently causes a difference in the pore peak position. Precipitated silicic acid, which is susceptible to crushing of particles, is expected to have a low particle structural strength and good dispersion in rubber, and such a tendency actually exists. In the precipitated silica having a ratio A / B of less than 1.4, the particle structure is strong, the progress of destruction to secondary particles or less during mercury injection by the mercury method is small, the dispersion is difficult even in rubber, and the strength is insufficient. Become. However, BE
The same tendency is observed for precipitated silica having a high T specific surface area (more than 200 m 2 / g). However, the BET specific surface area is
If it is higher than 200 m 2 / g, the cohesiveness between the particles becomes strong and poor dispersion occurs, which is not preferable. Ratio A / B
Is preferably in the range from 1.5 to 2.0.
【００１５】本発明の補強充填剤用の沈澱珪酸は、平均
粒子径が1〜12μｍ、好ましくは５〜８μｍの範囲であ
ることが、分散性と繰り返し荷重などの動的疲労に対す
る耐久性に優れるという観点から好ましい。The precipitated silicic acid for reinforcing filler of the present invention has an average particle diameter of 1 to 12 μm, preferably 5 to 8 μm, and is excellent in dispersibility and durability against dynamic fatigue such as repeated load. It is preferable from the viewpoint of.
【００１６】本発明の吸油量、ＢＥＴ法比表面積、シア
ーズ滴定量（Ｖｍｌ）とＢＥＴ比表面積（ｍ2／ｇ）と
の関係式におけるＣの値、及び比Ａ／Ｂが所定の範囲に
ある沈澱珪酸は、以下のように製造することができる。
本発明の沈澱珪酸は、珪酸アルカリと鉱酸とを反応させ
る湿式法沈澱珪酸の製造方法により得られる。例えば、
珪酸アルカリと鉱酸とを並行して反応槽に添加する方法
（同時滴下反応法）を用い、かつ反応溶液の温度を９０
℃以上、好ましくは９６℃以上に維持し、かつ反応液の
過剰アルカリ濃度が０〜０．０１ｍｏｌ／ｌを越えない
ように維持しながら、同時滴下反応を沈澱懸濁中の固体
濃度が４０〜６５ｇ／ｌになるまで行う。同時滴下反応
法では、沈澱珪酸の生成によりゲル化が起こり、反応開
始時間からこのゲル化までの時間、さらには反応終了ま
での時間を変化させることで、沈澱珪酸の物性をコント
ロールできる。本発明の沈澱珪酸の製造方法では、反応
開始時間からこのゲル化までの時間を例えば、40〜50分
とし、反応終了までの時間を70〜90分とする。反応終了
後、鉱酸で上記沈澱懸濁液のｐＨを５以下に調整し、沈
澱物を濾過、水洗、乾燥させ場合により粉砕又は分級す
る。The value of C in the relational expression between the oil absorption, the BET specific surface area, the Sears titration (Vml) and the BET specific surface area (m 2 / g), and the ratio A / B of the present invention are within predetermined ranges. Precipitated silicic acid can be produced as follows.
The precipitated silicic acid of the present invention is obtained by a wet method for producing precipitated silicic acid by reacting an alkali silicate with a mineral acid. For example,
A method in which an alkali silicate and a mineral acid are added to a reaction vessel in parallel (simultaneous dropping reaction method) is used, and the temperature of the reaction solution is adjusted to 90.
C. or higher, preferably 96 ° C. or higher, and while maintaining the excess alkali concentration of the reaction solution not to exceed 0 to 0.01 mol / l, the simultaneous dropping reaction was carried out so that the solid concentration in the precipitate suspension was 40 to 40 mol / l. Perform until 65 g / l. In the simultaneous dropping reaction method, gelation occurs due to the formation of precipitated silicic acid, and the physical properties of precipitated silicic acid can be controlled by changing the time from the reaction start time to the gelation, and further, the time from the completion of the reaction. In the method for producing precipitated silica of the present invention, the time from the reaction start time to the gelation is, for example, 40 to 50 minutes, and the time from the reaction end to 70 to 90 minutes. After completion of the reaction, the pH of the precipitate suspension is adjusted to 5 or less with a mineral acid, and the precipitate is filtered, washed with water, dried, and optionally ground or classified.
【００１７】上記反応において、反応温度は得られる沈
澱珪酸のＢＥＴと相関があり、反応温度が高い程一次粒
子の成長が早くＢＥＴ比表面積は低くなる傾向にある。
反応温度９０℃以下では粒子の成長が遅く、本発明の目
的であるゴム中での分散性の良い沈澱珪酸を得ることが
困難となる。９６℃以上の温度とすることで、ＢＥＴ法
比表面積が１２０〜２００m2/gの範囲にある、シリコー
ンゴム中での分散性が良好な沈澱珪酸を得ることができ
る。又、同時滴下反応法における反応液中の過剰アルカ
リ濃度を０ｍｏｌ／ｌ〜０．０１ｍｏｌ／ｌと極めて狭
い範囲に限定することで、目的とする物性及び上記に記
載したシアーズ滴定量とＢＥＴとの関係式が得られる。
さらに、同時滴下反応法における反応終点時の沈澱懸濁
液中の固体濃度を４０ｇ／ｌから６５ｇ／ｌの範囲に限
定する。固体濃度が４０ｇ／ｌ未満では、ＢＥＴ法比表
面積が２００ｍ2／ｇを越えると同時に凝集力の強い沈
澱珪酸となり分散不良を起こし易くなる傾向がある。固
体濃度が６５ｇ／ｌを越えるとＢＥＴ比表面積が１２０
ｍ2／ｇより低くなると同時にゴムの補強効果も低下す
る傾向がある。さらに、同時滴下反応法の反応開始時間
からこのゲル化までの時間及び、反応終了までの時間
は、吸油量及び比Ａ／Ｂに影響を与える。但し、比Ａ／
Ｂは、ＢＥＴ比表面積により変化する。このような点を
考慮して、反応開始時間からこのゲル化までの時間は40
〜70分とし、反応終了までの時間を70〜90分とする。こ
うすることで、吸油量を２００ ｃｃ/100g以下とし、
かつ比Ａ／Ｂを１．４以上とすることができる。In the above reaction, the reaction temperature has a correlation with the BET of the precipitated silicic acid obtained, and the higher the reaction temperature, the faster the primary particles grow and the lower the BET specific surface area.
At a reaction temperature of 90 ° C. or lower, the growth of particles is slow, and it is difficult to obtain precipitated silica having good dispersibility in rubber, which is the object of the present invention. By setting the temperature to 96 ° C. or higher, precipitated silica having a BET specific surface area of 120 to 200 m 2 / g and having good dispersibility in silicone rubber can be obtained. In addition, by limiting the excess alkali concentration in the reaction solution in the simultaneous dropping reaction method to an extremely narrow range of 0 mol / l to 0.01 mol / l, the desired physical properties and the above-mentioned Sears titration and BET can be determined. The relational expression is obtained.
Furthermore, the solid concentration in the precipitate suspension at the end of the reaction in the simultaneous dropping reaction method is limited to the range of 40 g / l to 65 g / l. If the solid concentration is less than 40 g / l, the specific surface area of the BET method exceeds 200 m 2 / g, and at the same time, precipitated silica having a strong cohesive force tends to be formed, which tends to cause poor dispersion. When the solid concentration exceeds 65 g / l, the BET specific surface area becomes 120.
It becomes lower than m 2 / g and at the same time the rubber reinforcing effect also tends to decrease. Further, the time from the reaction start time to the gelation in the simultaneous dropping reaction method and the time from the completion of the reaction affect the oil absorption and the ratio A / B. However, the ratio A /
B changes depending on the BET specific surface area. Considering these points, the time from the reaction start time to this gelation is 40
7070 minutes, and the time until the completion of the reaction is 70-90 minutes. By doing so, the oil absorption can be reduced to 200 cc / 100g or less,
In addition, the ratio A / B can be set to 1.4 or more.
【００１８】シリコーンゴムの充填剤として必要なこと
は、シリコーンゴム自体の特徴を侵さない化学的に安定
で、補強効果を示すことであり、その代表的な充填剤が
沈澱珪酸である。しかしながら、沈澱珪酸も種々の反応
処方により表面状態、粒子径、ストラクチャーと呼ばれ
る三次元構造等のいわゆる構造性に違いを生じ、ひいて
はゴム性質を決定するポイントとなる成分といわれてい
る。本発明の目的とする作業性、動的疲労耐久性向上は
沈澱珪酸の細孔容積や細孔分布或は吸油能等で議論され
る、粒子の構造性、および比表面積等で議論される一次
粒子サイズ、又、ゴム中への分散しやすさ等、粒子構造
をいかに持たせるかが重要なポイントである。本発明の
沈澱珪酸は、シリコーンゴムに配合時に他の物性を損な
うことなく、優れた作業性、及び動的疲労耐久性を発揮
する。What is needed as a filler for the silicone rubber is that it is chemically stable without affecting the characteristics of the silicone rubber itself and has a reinforcing effect. A typical filler is precipitated silicic acid. However, precipitated silicic acid is also said to be a component that determines the rubber properties due to the difference in the so-called structural properties such as the surface state, particle size, and three-dimensional structure called the structure due to various reaction recipes. The workability and dynamic fatigue durability improvement of the object of the present invention are discussed in terms of pore volume, pore distribution or oil absorption capacity of precipitated silicic acid, and the primary properties discussed in terms of particle structure and specific surface area. The important point is how to give the particle structure such as the particle size and the ease of dispersion in rubber. The precipitated silicic acid of the present invention exhibits excellent workability and dynamic fatigue durability without impairing other physical properties when compounded with silicone rubber.
【００１９】[0019]
【実施例】以下、本発明を更に具体的に実施例及び比較
例を挙げて説明する。尚、各物性値等の測定は次に示す
方法により実施した。結果は表１に示す。 １．ＢＥＴ比表面積 ＢＥＴ比表面積はＪＩＳＺー８８３０（気体吸着による
粉体の比表面積測定方法）に準じ、全自動粉体比表面積
測定装置 ＡＭＳー８０００（大倉理研社製）を用いて
１点法により測定した。サンプルは約０．０５ｇを２０
０℃×３０分の前処理を行って測定した。 単位
ｍ2／ｇ ２．吸油量 ＪＩＳＫ５１０１（顔料試験法）による吸油量測定法に
準じて測定を行った。 ３．細孔容積 ◇Ｎ2法 ＡＳＡＰ２４００（島津製作所（株）社
製）を用いて、非晶質シリカを２００℃、１００ミリト
ール以下の条件で、２時間脱気した後窒素の吸脱着等温
線を測定後、その結果をJ.Am.Chem.Soc.73,373(1951)記
載の方法、 Barrett- Joyner-Halende法を用いて、ピー
ク値細孔径を求めた。 ◇Ｈｇ法 水銀ポロシメーター２０００型（伊国Carl
o Erba社製）を用いて水銀圧入法によって測定。圧力を
１〜２０００ｂａｒまで変化させ細孔直径１５μｍ〜７
４Åの水銀圧入量を測定し、細孔直径のピーク位置を求
めた。 ４．シラノール基密度 Ｇ．Ｗシアーズによるシアーズ数（アナリテイカル ケ
ミストリー 第１２巻、１９５６、１９８２〜１９８３
項記載の方法） ５．動的疲労耐久性の測定 シリコーン生ゴム１００部と沈殿珪酸４０部、ウエッタ
ー（ジメチルエトキシシラン）２部を６インチロールを
用いて１０分間混練りしたコンパウンドをギヤーオーブ
ンで２００℃、５時間熱処理を行った。このコンパウン
ドを練り戻した後、架橋剤（２、５ージメチルー２、５
ジ（ｔ−ブチルパーオキシ）ヘキサン）０．５部を加
え、再度６インチロールを用いて添加混合した後、成型
温度１６５℃で１０分間プレス加硫したものを２００℃
で４時間二次加硫して、厚さ２ｍｍのシートを作成し、
ＪＩＳ３号ダンベル片に切り出した。このダンベル片を
デマッチャー屈曲疲労試験機（東洋精機（株）社製）を
用いて０〜１００％の繰り返し伸張を与え、５個の試験
片による破断時までの回数平均値を求め、この値を動的
疲労特性とした。測定結果は市販の沈殿珪酸（ニップシ
ールＬＰ：日本シリカ工業（株）社製）を用いて得られ
た結果を１００とし、相対値で求めた。 ６．ゴム物性の測定 ◇一般加硫物特性 動的疲労耐久性に用いた厚さ２ｍｍの別のシートを用い
て、旧ＪＩＳＫ６３０１の架橋ゴム物性試験方法に従っ
て実施した。 ７．作業性 ロール混練り時における喰い込み性について、良好なも
のを○、普通のもの△、悪いものを×で表示した。The present invention will be described below more specifically with reference to examples and comparative examples. In addition, the measurement of each physical property value etc. was implemented by the method shown below. The results are shown in Table 1. 1. BET specific surface area The BET specific surface area is measured by a one-point method using a fully automatic powder specific surface area measuring device AMS-8000 (manufactured by Okura Riken Co., Ltd.) in accordance with JISZ-8830 (method for measuring specific surface area of powder by gas adsorption). did. The sample is about 0.05g 20
The pretreatment was performed at 0 ° C. for 30 minutes to measure. unit
m 2 / g 2. Oil absorption The measurement was carried out according to the oil absorption measurement method according to JIS K5101 (pigment test method). 3. Pore volume ◇ N 2 method Using ASAP2400 (manufactured by Shimadzu Corporation), amorphous silica was degassed at 200 ° C. and 100 mTorr or less for 2 hours, and then nitrogen adsorption / desorption isotherm was measured. Thereafter, the results were used to determine the peak pore diameter using the Barrett-Joyner-Halende method described in J. Am. Chem. Soc. 73, 373 (1951). ◇ Hg method mercury porosimeter 2000 type (Iku Carl
o Erba Corporation) using the mercury intrusion method. The pressure is changed from 1 to 2000 bar and the pore diameter is from 15 μm to 7
The mercury intrusion amount of 4 ° was measured, and the peak position of the pore diameter was determined. 4. G. Silanol group density Sears number by W Sears (Analytical Chemistry Vol. 12, 1956, 1982-1983)
Method described in section) 5. Measurement of dynamic fatigue durability A compound obtained by kneading 100 parts of silicone raw rubber, 40 parts of precipitated silica, and 2 parts of a wetter (dimethylethoxysilane) for 10 minutes using a 6-inch roll is heat-treated at 200 ° C. for 5 hours in a gear oven. Was. After kneading the compound, the crosslinking agent (2,5-dimethyl-2,5
0.5 parts of di (t-butylperoxy) hexane) was added and mixed again using a 6-inch roll, followed by press vulcanization at a molding temperature of 165 ° C. for 10 minutes, followed by 200 ° C.
4 hours secondary vulcanization to make a 2mm thick sheet,
Cut out into JIS No. 3 dumbbell pieces. This dumbbell piece was repeatedly stretched by 0 to 100% using a dematcher bending fatigue tester (manufactured by Toyo Seiki Co., Ltd.), and the average number of times until breakage by five test pieces was determined. Dynamic fatigue characteristics were used. The measurement results were obtained as relative values, with the result obtained using commercially available precipitated silica (Nip Seal LP: manufactured by Nippon Silica Industry Co., Ltd.) as 100. 6. Measurement of rubber properties ◇ General vulcanizate properties Using another sheet having a thickness of 2 mm used for the dynamic fatigue durability, it was carried out in accordance with the crosslinked rubber property test method of the former JIS K6301. 7. Workability Regarding the biting property at the time of kneading the rolls, a good one was indicated by 、, a normal one was indicated by △, and a poor one was indicated by ×.
【００２０】（実施例１）撹袢機を備えた１８０リット
ルのジャケット付きステンレス反応槽に、水９３リット
ルと珪酸ナトリウム水溶液（ＳｉＯ2１６０ｇ／ｌ、Ｓ
ｉＯ2／Ｎａ2Ｏモル比３．３)０．６リットルを入れ、
９８℃に加熱した。この時の溶液Ｎａ2Ｏ濃度は０．０
０５ｍｏｌ／ｌであった。本水溶液温度を９８℃に維持
しながら、上記同様のケイ酸ナトリウム水溶液流量５４
０ミリリットル／分と硫酸（１８ｍｏｌ／ｌ）流量２４
ミリリットル／分を同時に滴下する。同時滴下は反応溶
液中のＮａ2Ｏ濃度を０．０〜０．０１ｍｏｌ／ｌの範
囲を維持しながら、同時滴下反応を行う。反応途中から
反応溶液は白濁をはじめ、４５分目に粘度が上昇してゲ
ル状溶液となった。更に、添加を続けて８０分で反応を
停止した。この時の溶液中のシリカ濃度は５１ｇ／ｌで
あった。引き続いて上記と同様の硫酸を添加して、溶液
ＰＨ３で酸性化を終了して珪酸スラリーを得た。得られ
た珪酸スラリーをフィルタープレスで濾過、水洗を行っ
て湿潤ケーキを得た。このケーキを定温乾燥機を用いて
乾燥した後、粉砕分級し、嵩比重７２ｇ／ｌ（ＪＩＳＫ
−５１０１顔料試験法に基ずいて実施）の沈殿珪酸を得
た。Example 1 93 liters of water and a sodium silicate aqueous solution (160 g / l of SiO 2 ,
iO 2 / Na 2 O molar ratio 3.3) were placed 0.6 liters
Heated to 98 ° C. The solution Na 2 O concentration at this time was 0.0
It was 05 mol / l. While maintaining the temperature of the aqueous solution at 98 ° C., the flow rate of the aqueous sodium silicate solution was 54
0 ml / min and sulfuric acid (18 mol / l) flow rate 24
Milliliter / min is dropped simultaneously. Simultaneous dropping is performed while maintaining the Na 2 O concentration in the reaction solution in the range of 0.0 to 0.01 mol / l. During the course of the reaction, the reaction solution became cloudy, and the viscosity increased at 45 minutes to form a gel-like solution. Further, the addition was continued and the reaction was stopped in 80 minutes. At this time, the silica concentration in the solution was 51 g / l. Subsequently, the same sulfuric acid as above was added, and the acidification was completed with the solution PH3 to obtain a silicic acid slurry. The obtained silicic acid slurry was filtered with a filter press and washed with water to obtain a wet cake. The cake was dried using a constant temperature drier, pulverized and classified, and had a bulk specific gravity of 72 g / l (JISK
(Implemented according to -5101 pigment test method).
【００２１】（実施例２）実施例１と同容器及び同原料
を使用し、水９３リットルと珪酸ナトリウム０．６リッ
トルを入れ、９７℃に加熱した。この時の溶液Ｎａ2O濃
度は０．００５mol／ｌであった。本水溶液温度を９７
℃に維持しながら、上記同様のケイ酸ナトリウム水溶液
流量５４０ミリリットル／分と硫酸流量２４ミリリット
ル／分を同時に滴下する。同時滴下は反応溶液中のNa2O
濃度を０．００〜０．０１ｍｏｌ／ｌの範囲を維持しな
がら、同時滴下反応を行う。反応途中から反応溶液は白
濁をはじめ、４７分目に粘度が上昇してゲル状溶液とな
った。更に、添加を続けて７５分で反応を停止した。こ
の時の溶液中のシリカ濃度は４９ｇ／ｌであった。引き
続いて上記と同様の硫酸を添加して、溶液ＰＨ３で酸性
化を終了し、珪酸スラリーを得た。得られたスラリーは
実施例１と同一の濾過、水洗、乾燥、粉砕・分級の製造
工程を用い、嵩比重 ６９ｇ／ｌの沈澱珪酸を得た。Example 2 93 liters of water and 0.6 liter of sodium silicate were charged in the same container and the same raw material as in Example 1, and heated to 97 ° C. At this time, the solution Na 2 O concentration was 0.005 mol / l. The temperature of this aqueous solution is 97
While maintaining the temperature at ° C., a flow rate of 540 ml / min of the aqueous sodium silicate solution and a flow rate of 24 ml / min of sulfuric acid as described above are simultaneously dropped. Simultaneous dropping is performed using Na 2 O in the reaction solution.
Simultaneous dropping reaction is performed while maintaining the concentration in the range of 0.00 to 0.01 mol / l. During the course of the reaction, the reaction solution became cloudy, and the viscosity increased at 47 minutes to become a gel-like solution. Further, the addition was continued and the reaction was stopped in 75 minutes. At this time, the silica concentration in the solution was 49 g / l. Subsequently, the same sulfuric acid as above was added, and the acidification was completed with a solution PH3 to obtain a silicic acid slurry. The obtained slurry was subjected to the same filtration, washing, drying, pulverization and classification steps as in Example 1 to obtain precipitated silica having a bulk specific gravity of 69 g / l.
【００２２】（実施例３）実施例１と同容器及び同原料
を使用し、水９３リットルと珪酸ナトリウム０．６リッ
トルを入れ、９６℃に加熱した。この時の溶液Ｎａ2O濃
度は０．００５mol／ｌであった。本水溶液温度を９６
℃に維持しながら、上記同様のケイ酸ナトリウム水溶液
流量５４０ミリリットル／分と硫酸流量２４ミリリット
ル／分を同時に滴下する。同時滴下は反応溶液中のNa2O
濃度を０．００〜０．０１ｍｏｌ／ｌの範囲を維持しな
がら、同時滴下反応を行う。反応途中から反応溶液は白
濁をはじめ、４７分目に粘度が上昇してゲル状溶液とな
った。更に、添加を続けて７５分で反応を停止した。こ
の時の溶液中のシリカ濃度は４９ｇ／ｌであった。引き
続いて上記と同様の硫酸を添加して、溶液ＰＨ３で酸性
化を終了し、珪酸スラリーを得た。得られたスラリーは
実施例１と同一の濾過、水洗、乾燥、粉砕・分級の製造
工程を用い、嵩比重 ６６ｇ／ｌの沈澱珪酸を得た。Example 3 93 liters of water and 0.6 liter of sodium silicate were charged in the same container and raw materials as in Example 1, and heated to 96 ° C. At this time, the solution Na 2 O concentration was 0.005 mol / l. The temperature of the aqueous solution is 96
While maintaining the temperature at ° C., a flow rate of 540 ml / min of the aqueous sodium silicate solution and a flow rate of 24 ml / min of sulfuric acid as described above are simultaneously dropped. Simultaneous dropping is performed using Na 2 O in the reaction solution.
Simultaneous dropping reaction is performed while maintaining the concentration in the range of 0.00 to 0.01 mol / l. During the course of the reaction, the reaction solution became cloudy, and the viscosity increased at 47 minutes to become a gel-like solution. Further, the addition was continued and the reaction was stopped in 75 minutes. At this time, the silica concentration in the solution was 49 g / l. Subsequently, the same sulfuric acid as above was added, and the acidification was completed with a solution PH3 to obtain a silicic acid slurry. The obtained slurry was subjected to the same filtration, washing, drying, pulverization and classification steps as in Example 1 to obtain precipitated silica having a bulk specific gravity of 66 g / l.
【００２３】（比較例１）撹袢機を備えた１８０リット
ルのジャケット付きステンレス反応槽に、水９３リット
ルと珪酸ナトリウム水溶液（ＳｉＯ2１６０ｇ／ｌ、Ｓ
ｉＯ2／Ｎａ2Ｏモル比３．３)０．６リットルを入れ、
８７℃に加熱した。この時の溶液Ｎａ2Ｏ濃度は０．０
０５ｍｏｌ／ｌであった。本水溶液温度を８７℃に維持
しながら、上記同様のケイ酸ナトリウム水溶液流量５４
０ミリリットル／分と硫酸（１８ｍｏｌ／ｌ）流量２４
ミリリットル／分を同時に滴下する。同時滴下は反応溶
液中のＮａ2Ｏ濃度を０．０〜０．０１ｍｏｌ／ｌの範
囲を維持しながら、同時滴下反応を行う。反応途中から
反応溶液は白濁をはじめ、４８分目に粘度が上昇してゲ
ル状溶液となった。更に、添加を続けて１００分で反応
を停止した。この時の溶液中のシリカ濃度は５８ｇ／ｌ
であった。引き続いて上記と同様の硫酸を添加して、溶
液ＰＨ３で酸性化を終了して珪酸スラリーを得た。得ら
れた珪酸スラリーをフィルタープレスで濾過、水洗を行
って湿潤ケーキを得た。このケーキを定温乾燥機を用い
乾燥した後、粉砕分級し、嵩比重 ５７ｇ／ｌ（ＪＩＳ
Ｋ−５１０１ 顔料試験法に基づいて実施）の沈殿珪酸
を得た。Comparative Example 1 In a 180-liter jacketed stainless steel reactor equipped with a stirrer, 93 liters of water and an aqueous solution of sodium silicate (SiO 2 160 g / l, S
iO 2 / Na 2 O molar ratio 3.3) were placed 0.6 liters
Heated to 87 ° C. The solution Na 2 O concentration at this time was 0.0
It was 05 mol / l. While maintaining the temperature of the aqueous solution at 87 ° C., the flow rate of the aqueous sodium silicate solution was 54
0 ml / min and sulfuric acid (18 mol / l) flow rate 24
Milliliter / min is dropped simultaneously. Simultaneous dropping is performed while maintaining the Na 2 O concentration in the reaction solution in the range of 0.0 to 0.01 mol / l. During the reaction, the reaction solution became cloudy, and the viscosity increased at 48 minutes to form a gel-like solution. Further, the reaction was stopped in 100 minutes after the addition was continued. At this time, the silica concentration in the solution was 58 g / l.
Met. Subsequently, the same sulfuric acid as above was added, and the acidification was completed with the solution PH3 to obtain a silicic acid slurry. The obtained silicic acid slurry was filtered with a filter press and washed with water to obtain a wet cake. The cake was dried using a constant temperature drier, pulverized and classified, and the bulk specific gravity was 57 g / l (JIS
K-5101, carried out according to the pigment test method).
【００２４】（比較例２）比較例１と同容器及び同原料
を使用し、水８７リットルと珪酸ナトリウム６．０リッ
トルを入れ、９６℃に加熱した。この時の溶液Ｎａ2O濃
度は０．０５mol／ｌであった。本水溶液温度を９６℃
に維持しながら、上記同様のケイ酸ナトリウム水溶液流
量５４５ミリリットル／分と硫酸流量２４ミリリットル
／分を同時に滴下する。同時滴下は反応溶液中のNa2O濃
度を０．０４〜０．０６ｍｏｌ／ｌの範囲を維持しなが
ら、同時滴下反応を行う。反応途中から反応溶液は白濁
をはじめ、４３分目に粘度が上昇してゲル状溶液となっ
た。更に、添加を続けて１００分で反応を停止した。こ
の時の溶液中のシリカ濃度は６５ｇ／ｌであった。引き
続いて上記と同様の硫酸を添加して、溶液ＰＨ３で酸性
化を終了し、珪酸スラリーを得た。得られたスラリーは
比較例１と同一の濾過、水洗、乾燥、粉砕・分級の製造
工程を用い、嵩比重 ４８ｇ／ｌの沈澱珪酸を得た。Comparative Example 2 Using the same container and the same raw material as in Comparative Example 1, 87 liters of water and 6.0 liters of sodium silicate were charged, and heated to 96 ° C. At this time, the solution Na 2 O concentration was 0.05 mol / l. The aqueous solution temperature is 96 ° C
, And a flow rate of sodium silicate aqueous solution of 545 ml / min and a sulfuric acid flow rate of 24 ml / min are dropped simultaneously. The simultaneous dropping is performed while maintaining the Na 2 O concentration in the reaction solution in the range of 0.04 to 0.06 mol / l. During the reaction, the reaction solution became cloudy, and the viscosity increased at 43 minutes to become a gel-like solution. Further, the reaction was stopped in 100 minutes after the addition was continued. At this time, the silica concentration in the solution was 65 g / l. Subsequently, the same sulfuric acid as above was added, and the acidification was completed with a solution PH3 to obtain a silicic acid slurry. The obtained slurry was subjected to the same filtration, washing, drying, pulverization and classification steps as in Comparative Example 1 to obtain precipitated silica having a bulk specific gravity of 48 g / l.
【００２５】（比較例３）市販の沈澱珪酸（Ｎｉｐｓｉ
ｌ ＬＰ 日本シリカ工業（株）社製）を用い、粒度調
整し嵩比重 ６２ｇ／ｌのものを使用した。 （比較例４）市販の沈澱珪酸（Ｎｉｐｓｉｌ ＮＳ−Ｐ
日本シリカ工業（株）社製）を用い、粒度調整し嵩比
重 ５６ｇ／ｌのものを使用した。 （比較例５）市販の沈澱珪酸（Ｎｉｐｓｉｌ ＥＲ 日
本シリカ工業（株）社製）を用い、粒度調整し嵩比重
７２ｇ／ｌのものを使用した。Comparative Example 3 Commercially available precipitated silica (Nipsi)
l LP (manufactured by Nippon Silica Industry Co., Ltd.) and having a bulk specific gravity of 62 g / l. (Comparative Example 4) Commercially available precipitated silica (Nipsil NS-P)
Particle size was adjusted by using Nippon Silica Kogyo Co., Ltd., and the bulk specific gravity was 56 g / l. (Comparative Example 5) Using a commercially available precipitated silicic acid (Nipsil ER manufactured by Nippon Silica Industry Co., Ltd.), the particle size was adjusted and the bulk specific gravity was adjusted.
The one with 72 g / l was used.
【００２６】[0026]
【表１】 [Table 1]
【００２７】[0027]
【発明の効果】本発明の沈澱珪酸は、シリコーンゴム用
補強充填剤として使用すると、優れたゴム特性、特に動
的疲労耐久性を飛躍的に向上させることができる、とと
もに作業性も改善できる。When the precipitated silicic acid of the present invention is used as a reinforcing filler for silicone rubber, excellent rubber properties, especially dynamic fatigue durability, can be remarkably improved and workability can be improved.
Claims (4)
り、ＢＥＴ法比表面積が１２０〜２００m2/gの範囲であ
り、シアーズ滴定量（Ｖｍｌ）とＢＥＴ比表面積（ｍ2
／ｇ）との関係式Ｖ（ＮａＯＨ滴定量）ｍｌ＝1.5/100
×ＢＥＴ(m2/g)＋Ｃにおける、Ｃの値が０〜４の範囲で
あり、且つＮ2法で測定した細孔直径のピーク位置Ａ
（A）と水銀法で測定した細孔直径のピーク位置Ｂ（A）
との比Ａ／Ｂが１．４以上である沈澱珪酸からなること
を特徴とするシリコーンゴム補強充填剤。1. The oil absorption is 200 cc / 100 g or less, the BET specific surface area is in the range of 120 to 200 m 2 / g, the Sears titer (Vml) and the BET specific surface area (m 2
/ G) and V (NaOH titer) ml = 1.5 / 100
× BET (m 2 / g) + C, the value of C is in the range of 0 to 4, and the peak position A of the pore diameter measured by the N 2 method
(A) and peak position B (A) of pore diameter measured by mercury method
A precipitated silica having a ratio A / B of at least 1.4 to the silicone rubber reinforcing filler.
０ ｃｃ/100g以下の範囲である請求項１に記載の補強
充填剤。2. An oil absorption of at least 120 cc / 100 g, 18
The reinforcing filler according to claim 1, which is in a range of 0 cc / 100 g or less.
る請求項１又は２に記載の補強充填剤。3. The reinforcing filler according to claim 1, wherein the value of C is in the range of 2.0 or more and 4 or less.
囲である請求項１〜３のいずれか１項に記載の補強充填
剤。4. The reinforcing filler according to claim 1, wherein the ratio A / B is in the range of 1.5 or more and 2.0 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11131568A JP2000319513A (en) | 1999-05-12 | 1999-05-12 | Filler for reinforcing silicone rubber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11131568A JP2000319513A (en) | 1999-05-12 | 1999-05-12 | Filler for reinforcing silicone rubber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000319513A true JP2000319513A (en) | 2000-11-21 |
Family
ID=15061114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11131568A Pending JP2000319513A (en) | 1999-05-12 | 1999-05-12 | Filler for reinforcing silicone rubber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000319513A (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58208124A (en) * | 1982-05-28 | 1983-12-03 | Nippon Shirika Kogyo Kk | Hydrophobic precipitated silicic acid and its manufacture |
| JPH05202297A (en) * | 1991-09-05 | 1993-08-10 | Nippon Shirika Kogyo Kk | Reinforcing filler for silicone rubber |
| JPH06171922A (en) * | 1992-12-08 | 1994-06-21 | Nippon Shirika Kogyo Kk | Hydrous silicate for silicone rubber-reinforced filler |
| JPH07172815A (en) * | 1993-10-07 | 1995-07-11 | Degussa Ag | Precipitated silicic acid, its preparation and vulcanizable elastic rubber mixture containing this and vulcanized rubber |
| JPH0848821A (en) * | 1994-08-04 | 1996-02-20 | Nippon Silica Ind Co Ltd | Filler for polyolefin-based resin sheet |
| JPH0848818A (en) * | 1994-08-04 | 1996-02-20 | Nippon Silica Ind Co Ltd | Hydrated silicic acid for reinforcement of rubber and its production |
| JPH09268007A (en) * | 1996-04-02 | 1997-10-14 | Nippon Silica Ind Co Ltd | Hydrated silicic acid suitable as filler for silicone rubber |
| JPH09302230A (en) * | 1996-05-13 | 1997-11-25 | Shin Etsu Chem Co Ltd | Silicone rubber composition |
| JPH10194723A (en) * | 1996-12-27 | 1998-07-28 | Nippon Silica Ind Co Ltd | Water-containing silicic acid for rubber reinforcement and its production |
| JPH10194722A (en) * | 1996-12-27 | 1998-07-28 | Nippon Silica Ind Co Ltd | Water-containing silicic acid for elastomer reinforcement and its production |
| JPH11236505A (en) * | 1998-02-23 | 1999-08-31 | Nippon Silica Ind Co Ltd | Silicon rubber-reinforcing filler excellent in workability |
| JPH11236208A (en) * | 1998-02-25 | 1999-08-31 | Nippon Silica Ind Co Ltd | Hydrous silica for rubber reinforcement |
-
1999
- 1999-05-12 JP JP11131568A patent/JP2000319513A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58208124A (en) * | 1982-05-28 | 1983-12-03 | Nippon Shirika Kogyo Kk | Hydrophobic precipitated silicic acid and its manufacture |
| JPH05202297A (en) * | 1991-09-05 | 1993-08-10 | Nippon Shirika Kogyo Kk | Reinforcing filler for silicone rubber |
| JPH06171922A (en) * | 1992-12-08 | 1994-06-21 | Nippon Shirika Kogyo Kk | Hydrous silicate for silicone rubber-reinforced filler |
| JPH07172815A (en) * | 1993-10-07 | 1995-07-11 | Degussa Ag | Precipitated silicic acid, its preparation and vulcanizable elastic rubber mixture containing this and vulcanized rubber |
| JPH0848821A (en) * | 1994-08-04 | 1996-02-20 | Nippon Silica Ind Co Ltd | Filler for polyolefin-based resin sheet |
| JPH0848818A (en) * | 1994-08-04 | 1996-02-20 | Nippon Silica Ind Co Ltd | Hydrated silicic acid for reinforcement of rubber and its production |
| JPH09268007A (en) * | 1996-04-02 | 1997-10-14 | Nippon Silica Ind Co Ltd | Hydrated silicic acid suitable as filler for silicone rubber |
| JPH09302230A (en) * | 1996-05-13 | 1997-11-25 | Shin Etsu Chem Co Ltd | Silicone rubber composition |
| JPH10194723A (en) * | 1996-12-27 | 1998-07-28 | Nippon Silica Ind Co Ltd | Water-containing silicic acid for rubber reinforcement and its production |
| JPH10194722A (en) * | 1996-12-27 | 1998-07-28 | Nippon Silica Ind Co Ltd | Water-containing silicic acid for elastomer reinforcement and its production |
| JPH11236505A (en) * | 1998-02-23 | 1999-08-31 | Nippon Silica Ind Co Ltd | Silicon rubber-reinforcing filler excellent in workability |
| JPH11236208A (en) * | 1998-02-25 | 1999-08-31 | Nippon Silica Ind Co Ltd | Hydrous silica for rubber reinforcement |
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