JPS6037824B2 - Anti-vibration rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and improved anti-vibration rubber composition.

Butyl rubber has the characteristic of having a lower impact resilience compared to other synthetic rubbers (Kogyo Materials, April 1967 issue, No. 9).
(See pages 0 to 91). Utilizing this property, it has been used in various applications including the electronics technology field, such as vibration-proof rubber for mustard cord needles and mirror actuators for video discs.

However, butyl rubber is subject to temperature changes (-20 to 80q
Changes in physical properties due to (o), especially the shift of the resonance point in vibration transmission, are large, and this change in physical properties causes noise, noise, or distortion in audio, images, or other signals.

These distortions and the like have become a major problem in the application field of electronics technology, where technological progress is remarkable.
On the other hand, with the aim of reducing only the impact resilience of silicone rubber within a range that does not impair the inherent heat resistance and cold resistance of silicone rubber, silicone rubber is used as the main component, and isobutylene is added to a certain range within a certain range. Anti-vibration rubber compositions containing the following have been proposed.

The present invention aims to provide a new composition that solves the problems of conventional butyl rubber as described above.
It consists of 10 parts by weight of diorganopolysiloxane and 3 to 7 parts by weight of diorganopolysiloxane, and there is almost no change (deviation) in the frequency at the resonance point over a wide temperature range.

Specifically, it is a vibration-proof structure made only of butyl rubber that is designed to have a resonance point of approximately 90℃ at room temperature.
In contrast, the vibration damping rubber obtained from the composition of the present invention has almost no change in rebound modulus even with temperature changes, and the resonance point shift is approximately ±30° in the temperature range of is within about ±10 degrees. In addition, it has been reported that rubber materials made by blending two or more rubber components have multiple resonance points in vibration absorption, making them unsuitable for the above-mentioned applications. ``How to Use'' by Tamio Usami, published by Ohmsha, p. 27), the vibration-proofing rubber obtained from the composition of the present invention does not exhibit any of the above-mentioned phenomena, even though it is composed of two components. .

Hereinafter, the vibration-proof rubber composition according to the present invention will be explained in detail.

First, the {i} component used as the main component in the present invention is butyl rubber-based raw rubber, which can include various conventionally known rubbers, specifically butyl rubber, butyl bromide rubber, etc. Examples include halogenated butyl rubber such as chlorinated butyl rubber, butyl rubber containing no isoprene, or polymer blends mainly composed of butyl rubber. Examples of the polymer blends used include styrene rubber, acrylic rubber, isoprene rubber, etc. can give.

In the present invention, this component (A) has a Mooney viscosity of 4.
Preferably, the Mooney viscosity is within the range of 0 to 80, and by using a Mooney viscosity within the above range, the object of the present invention can be achieved more reliably.

Next, the diorganopolysiloxane used in the present invention as the [o-component] has an average compositional formula of RaS, for example.
io, in which R represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, including alkyl groups such as methyl, ethyl, propyl, or butyl groups, Examples include alkenyl groups such as vinyl groups or allyl groups, aryl groups such as phenyl groups, and groups in which part or all of the hydrogen atoms of these groups are substituted with halogen atoms or the like.

a is 1.98 to 2.02. Examples of such diorganopolysiloxanes include dimethylpolysiloxane, methylvinylpolysiloxane, and methylvinylpolysiloxane in which both ends of the molecular chain are blocked with a triorganosilyl group such as a trimethylsilyl group, a dimethylvinyl group, or a diphenylmethyl group, or a hydroxyl group. Two or more types of siloxane units selected from enylpolysiloxane or dimethylsiloxane units, methylvinylsiloxane units, methylphenylsiloxane units, methylhydrogensiloxane units, methylallylsiloxane units, methylacylsiloxane units, methylfluoropropylsiloxane units, etc. An example is a block or random copolymer consisting of a siloxane in which both ends of the molecular chain are blocked with groups similar to those mentioned above. It is preferable that this diorganopolysiloxane has a viscosity of 10,000 centistokes or more at 250C, and if a siloxane with a viscosity lower than that is used, the final vibration-proof rubber obtained will have poor mechanical properties. Become.

Furthermore, this {.

] The component may be in the form of a so-called silicone rubber compound containing fillers or various other additives. It is essential that the amount of this {o-component used is in the range of 3 to 7 parts by weight, preferably 5 to 4 parts by weight, based on 100 parts by weight of the above-mentioned {o-component. If the amount used is less than 3 parts by weight, it will not be possible to improve the temperature dependence of the resonance point, which is the objective of the present invention.On the other hand, if the amount used is 7 parts by weight or more, the objective of the resonance effect can be achieved. However, on the other hand, the resulting anti-vibration rubber has a high rebound modulus (see Figure 1), making it impossible to apply it to the above-mentioned uses.

The composition of the present invention can be prepared by uniformly mixing the above-described components [a' and 'o'] using any conventionally known mixing device.

When curing the composition of the present invention consisting of the (i) and 'o- components to obtain a rubber-like elastic body, it is generally desirable to use a curing agent. different curing agents, i.e.
A method of using a curing agent for curing the component and a curing agent for curing the raw component, or ■(a)
This can be done by using a common curing agent for both components, such as penzoyl peroxide, 2,4-dichlorobenzoyl/ -Oxide,
2,4-dicumyl peroxide, 2,5-dimethylbis(2,5-tert-butylperoxy)hexane,
Examples include organic peroxides such as di-tert-butyl peroxide and ten-butyl perbenzoate. In addition, when the above component {o) has an alkenyl group directly connected to an elementary atom in the molecule, it is an organohydrodiene polymer. Xane and platinum or a platinum compound can also be used, and examples of the platinum compound include chloroplatinic acid, an alcohol compound of chloroplatinic acid, an aldehyde compound, or a complex of chloroplatinic acid and various olefins. Furthermore, in the present invention,
In addition to or in place of the various hardening agents mentioned above, it is also possible to use what is generally known as a hardening aid. Examples of hardening aids include metals such as zinc oxide, calcium oxide, or magnesium oxide. Examples include oxides, metal peroxides, and amine compounds such as diorthotolylguanidine salt of dicatechol and boric acid.

In the present invention, it is desirable to use only the above-mentioned curing aids for the reasons described below.

It is also possible to use sulfur and sulfur compounds, which are used in general organic synthetic rubber, as a hardening agent, but the anti-vibration rubber obtained by using these may be harmful to surrounding electrical or electronic equipment when applied. Their use should be avoided as much as possible as they have negative effects. In addition, since organic peroxides oxidatively depolymerize the double bonds in component {A}, when using organic peroxides, it is necessary to use butyl rubber with a chlorine content of 1 to 5% by weight as component {A}. It is preferable to use Furthermore, there is no problem in adding fillers, dyes, antioxidants, heat resistance improvers, etc. to the composition of the present invention, as necessary, as long as the purpose of the present invention is not impaired.

As explained above, the anti-vibration rubber obtained from the composition of the present invention has an extremely small frequency shift at the resonance point over a wide temperature range, and is suitable for use in the record stylus mounting part of record players and the mirror actuator of video discs. It can be widely applied to connectors or input terminals in various optotronics devices, other precision equipment that uses laser beams, projection televisions, etc. Next, examples of the present invention will be given, and all "parts" in the examples indicate "parts by weight."

Example Test 1 Essobutyl HT (trade name, butyl rubber manufactured by Esso Kagaku ■) 10 parts of anchor, 8 parts of diaphragm (specific surface area 200〆/2), 6 parts of zinc oxide, 3 parts of diorthotolyl guanidine salt of dicatechol and boric acid 1 part of magnesium oxide, methylvinyl polysiloxane whose molecular chain ends are blocked with trimethylsilyl groups (vinyl group content: 0.1 mol%, 25°C)
2,500,000 centistokes) or polysiloxanes in which both ends of the molecular chain are capped with trimethylsilyl groups, and the groups bonded to elementary atoms are 3,3,3-trifluoropropyl, methyl, and vinyl groups ( Vinyl group content 0.07 mol%, viscosity 1200000 centistokes at 25°C) 0, 10, 20,
30...90, 100 or 11 anchor part, dicumyl peroxide 2. $ parts (based on 100 parts of the organopolysiloxane) were uniformly mixed using a water-cooled mixing roll.

Next, the mixture obtained above was heated and pressed at 17,000 for 10 minutes to prepare a sample piece for measurement.

The rebound modulus of this product was measured according to JISK 6301, and the results are shown in the attached drawing (Figure 1). However, curve A shows the results when methylvinyl polysiloxane is used, and curve B shows the results when polysiloxane containing 3,3,3-trifluoropropyl group is used. Test 2 The same methylvinylpolysiloxane as used above was used as the diorganopolysiloxane, and the composition was the same as above except that the amount used was as shown in the table below. The mixture was uniformly mixed using a roll, and then a rectangular parallelepiped with 15 books on each side and an IQ cape in length was molded using heat and pressure.

This molded body 1 was adhered and integrated with a disk 2 made by Shinchiyuu with a thickness of 1.5 mm and a diameter of 15 mm using a commercially available primer to prepare a test body.

Next, as shown in Fig. 2, this test specimen was glued and integrated with the test specimen mounting part 3 of a vibrating device via a silicone sealant 4 (designed to have a resonance point at room temperature of 90 cycles), and this was subjected to forced vibration. Using a tester, the temperature was variously varied between -20 qo and 8000, and the fluctuation of the resonance frequency was investigated, and the results shown in the table below were obtained.
The results of Tests 1 and 2 described above show that the rubber elastic body having the composition of the present invention exhibits extremely small changes in rebound modulus and resonance point over a wide temperature range.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a composition of diorganopolysiloxane and butyl rubber.

FIG. 2 is a graph showing changes in rebound modulus when the blending ratio of xane is varied, and FIG. 2 is a cross-sectional view of a test piece for measuring changes in resonance frequency. DESCRIPTION OF SYMBOLS 1... Molded object made of the anti-pregnancy rubber composition according to the present invention, 2... Disc manufactured by Shinchiyu, 3... Test piece attachment part of a vibration device, 4... Silicone sealant.

Figure 1 Figure 2

Claims (1)

[Claims] 1. Vibration-damping rubber composition with small change in resonance point due to temperature change, consisting of (a) 100 parts by weight of butyl rubber-based raw rubber and (b) 3 to 70 parts by weight of diorganopolysiloxane 2 Amount of the diorganopolysiloxane blended is from 5 to 40 parts by weight.The vibration-proof rubber composition 3 according to claim 1, wherein the butyl rubber raw rubber is heated at 100°C.
4. The vibration-proof rubber composition 4 according to claim 1, wherein the diorganopolysiloxane has a Mooney viscosity of 40 to 80 at 25°C.
The vibration-proof rubber composition according to claim 1, which has a viscosity of 0 centistokes or more.