JPS601896B2 - Anti-vibration rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration-isolating rubber composition, and particularly to a vibration-isolating rubber composition with improved temperature characteristics and vibration damping effect.

Regarding vibration-isolating rubber compositions, those using polymeric materials with good vibration-damping properties such as butyl rubber have been widely used in dampers for supporting cantilevers of pickup cartridges and the like.

However, since the frequency of these vibration damping materials depends on temperature, there is a large shift in the resonance point, and the damping effect changes greatly depending on temperature, so the desired performance can only be maintained within a very narrow temperature range. This also had the disadvantage of poor workability due to the long heating time. On the other hand, regarding this damping material, silicone rubber exhibits stable physical properties over a wide range, so
A vibration-proof rubber composition made by blending polyisobutylene with this silicone rubber is also known (Tokukan Sho 54-14).
1957), but this composition cannot be co-vulcanized because polyisobutylene is difficult to be a vulcanized polymer, and this also affects its compatibility with silicone rubber, etc. Therefore, it cannot be co-vulcanized at high temperatures. preservation of,
Alternatively, during long-term use, polyisobutylene bleeds onto the surface, which causes its vibration damping properties to deteriorate significantly over time, and also has the disadvantage of poor adhesion to other resins and metals.

Regarding this vibration-proof rubber composition, the present inventors previously proposed a composition in which diorganopolysiloxane was blended with butyl rubber-based raw rubber (Special Publication No. 56-176444), but this was due to the resonance frequency fluctuation with respect to temperature. However, it was found that there was no improvement effect on vibration damping effect fluctuations with respect to temperature. The present invention relates to a vibration-damping rubber composition that solves these disadvantages, and is composed of parts by weight of silicone raw rubber 10,
) 20 to 100 parts by weight of halogenated butyl rubber having a halogen content of 0.5% or more, 10 to 20 parts by weight of a filler having an average particle diameter of 10 mm or less, and q organic peroxide curing agent. It is characterized by:

To explain this, the inventors of the present invention have conducted various studies on modifying a vibration damping composition composed of silicone rubber and butyl rubber, and found that when halogenated butyl rubber was selected as the butyl rubber, it was found that compared to butyl rubber, silicone rubber, etc. In addition to its excellent compatibility and kneading properties, it also has a fast vulcanization rate and can be co-vulcanized with silicone rubber using organic peroxides. The present invention was completed based on the discovery that when blended, the vibration damping effect as well as the reinforcing effect is improved.

The silicone raw rubber as a component constituting the anti-vibration composition of the present invention has the general formula RnSi04-n (where R is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, n
is a positive number from 1.9 to 2.02), and this 1
Examples of valent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, and butyl groups, alkenyl groups such as vinyl and allyl groups, aryl groups such as phenyl groups, or some or all of their hydrogen groups replaced with halogen atoms. Examples include groups substituted with, etc., and these have a viscosity of 100 ratio P or more, preferably 500 ratio P or more, at 25%.

The halogenated butyl rubber as the 'o component constituting the composition of the present invention is obtained by partially introducing halogen groups such as chlorine and bromine into the chain molecules of butyl rubber obtained by polymerizing i-butene and isoprene. However, the halogenated butyl rubber used in the present invention has a halogen content of 0.
．． The content must be 5% by weight or more.

This means that when it is less than 0.5% by weight, there is no significant difference in compatibility with silicone rubber, kneadability, and vulcanization properties from that of non-halogenated butyl rubber, and the object of the present invention is substantially achieved. This is because it is not done. In addition, the Mooney viscosity of this halogenated butyl rubber is preferably in the range of 20 to 80 from the viewpoint of dispersion uniformity with silicone rubber and sloshing workability. However, outside this range, the kneading workability and dispersibility become poor, making it difficult to control the quality and properties. Note that if the amount of this halogenated butyl rubber is less than 2 parts by weight, the anti-vibration effect will be insufficient.
If more than 10 parts by weight is added, the compatibility between silicone rubber and butyl rubber will be exceeded, and the uniformity of their dispersion will be impaired. , preferably 30 to 8 parts by weight. In the anti-vibration composition of the present invention, a filler is added as a component to silicone rubber as a component and halogenated butyl rubber as a component. Examples include fine silica powder, diatomite, iron oxide, titanium oxide, zinc oxide, calcium carbonate, and carbon black.

If this filler is used in too small an amount, it cannot be expected to improve the reinforcing effect or vibration-proofing effect, and if it exceeds 200 parts by weight, it is difficult to knead, and if it is added in an appropriate amount, it will not have the properties as a vibration-proof rubber. Therefore, this should be 10 to 20 parts by weight, preferably 20 to 10 parts by weight, per 100 parts by weight of silicone rubber, but this also applies if the average particle size is 10 parts by weight or more. Since this addition hardly improves the vibration damping effect, it is necessary to make it less than 10 ridges. Further, the vibration isolating material of the present invention is as described above [
Since this composition is obtained by heating and curing a composition consisting of one component in the presence of an organic peroxide, this composition requires the addition of an organic peroxide curing agent as nine components. However, it may be a known material for silicone rubber, including dibenzoyl/f-oxide, dicumyl/gu oxide, bis(2,4-dichlorobenzoyl) peroxide, and pis(p-chlorobenzoyl) peroxide. Examples include oxide, t-butyl peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, and organic silyl paroxide and the like can also be used.

Usually one type of these peroxides should be used, but
These may be used in combination of two or more types, if necessary. In addition, when vulcanizing this one-component composition, a known co-curing agent such as trimethylolpropane-trimethacrylate, ethylene glyco-dimethacrylate, etc. is used together with the above-mentioned organic peroxide. Additionally, known vulcanization accelerators such as tetramethylthiuram disulfide or monosulfide may be added. The above-mentioned mixing operation of the A to B components to obtain the vibration-damping rubber composition of the present invention may be carried out using a known mixing means such as a Banbury mixer, two rolls, etc. It is better to add one ingredient little by little to the {i' component and the raw component, add a shearing force of 1×1 pidain/ground, thicken, and then mix the 8 ingredients.

However, it is also possible to dissolve the [A' component and 'O- component] in an organic solvent such as toluene or xylene, add one component to this, knead it in a ball mill, sieve, or machine, and then This may be carried out by evaporating the solvent and mixing the dry ingredients. Next, examples of the present invention will be given, and all parts in the examples indicate parts by weight.

Example 2 10 parts of dimethylpolysiloxane having a viscosity of 1 million cS at Qo, 7 parts of chlorobutyl rubber having a chlorine content of 1.2% by weight, and 5 parts of precipitated silica having an average particle size of 10 mm. After adding 2 parts of dicumyl peroxide and 0.5 part of trimethylolpropane-trimethacrylate as a co-vulcanizing agent, and mixing these uniformly with two rolls, 5 parts of dicumyl peroxide was added at 180 qo under a pressure of 200 k9/base.
A rectangular parallelepiped test piece of 1.2 skin x 1.2 side x 7 sides was prepared by heating under pressure for a period of time.

For comparison, the compositions listed in Table 1 were prepared for chlorobutyl rubber, silicone rubber and polyisobutylene, silicone rubber, chlorobutyl rubber and dimethylpolysiloxane, and test pieces similar to those described above were prepared from the cured products.

Next, these test pieces were glued to one side of the vibrating device with silicone sealant, and a one-day brass disk was similarly glued to the other side of the vibrating device, and this was used to adjust the temperature of each test piece. When the primary resonance frequency change, vibration damping effect change, and high temperature resistance were tested, the results shown in Table 2 were obtained, indicating that the vibration damping rubber composition of the present invention has low temperature dependence and is stable. It was confirmed that it exhibits anti-vibration effects.

Table 1 Table 2

Claims (1)

[Scope of Claims] 1 (a) 100 parts by weight of silicone raw rubber (b) 20 to 100 parts by weight of halogenated butyl rubber having a halogen content of 0.5% by weight or more (c) Filler with an average particle size of 10 μm or less A vibration-proof rubber composition comprising 10 to 200 parts by weight and (d) an organic peroxide curing agent.