JPH0665454A - Rubber composition for damping material - Google Patents

Abstract

(57) [Summary] [Structure] A halogenated butyl rubber is contained in a low impact resilience rubber composition containing polynorbornene as a main component. (Effect) This rubber composition for vibration damping materials has excellent vibration damping properties over a wide temperature range from low temperature to around room temperature, and further suppresses the increase in elastic modulus at low temperature, resulting in a low brittle fracture temperature. It is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a vibration damping material used in electric parts, machines, buildings and the like which are required to reduce or prevent vibration.

[0002]

2. Description of the Related Art Conventionally, polymer materials have been used as vibration damping materials for electric products such as computers and general household appliances, and mechanical parts. The damping property of the polymer material is
It is represented by the loss coefficient of each polymer material. The highest value (peak value) of the above loss coefficient is the glass transition temperature (Tg) of each polymer material, and the peak value of this loss coefficient,
That is, it is most effective to use a polymer material that is a vibration damping material near the glass transition temperature from the viewpoint of vibration damping. As the vibration damping material used for the above electric products and mechanical parts, those having a glass transition temperature around room temperature and exhibiting good vibration damping around this room temperature are usually used.

[0003]

However, although the above-mentioned vibration damping material exhibits a good vibration damping property near room temperature, it may be used in a practical temperature range depending on the product incorporated as the vibration damping material. Is on the low temperature side (0 ° C. or less), and in this case, sufficient vibration damping properties are not exhibited. Moreover, such a damping material has a problem that the elastic modulus becomes high in the low temperature region and brittle fracture occurs in the low temperature region.

The present invention has been made in view of the above circumstances and has good vibration damping performance over a wide temperature range from a low temperature to around room temperature, and further suppresses an increase in elastic modulus at a low temperature. It is an object of the present invention to provide a rubber composition for a vibration damping material having a lower brittle fracture temperature.

[0005]

In order to achieve the above object, the rubber composition for vibration damping material of the present invention is a low impact resilience rubber composition containing polynorbornene as a main component.
The composition is such that halogenated butyl rubber is compounded.

[0006]

In other words, the inventors of the present invention have good vibration damping performance in the low temperature region in addition to the room temperature, suppress the increase of the elastic modulus in the low temperature region, and have a brittle fracture temperature lower than the practical range. A series of studies have been conducted to ensure that the As a result, when a halogenated butyl rubber was blended with a low impact resilience rubber composition containing polynorbornene as a main component, it exhibited high damping performance at around room temperature (loss coefficient 0.8 or more) and high protection from low temperature to around room temperature. Vibration (loss coefficient 0.3 or more)
The inventors have found that the above is obtained, and further, the increase in elastic modulus at low temperatures is suppressed, and the brittle fracture temperature changes to a temperature lower than the practical range, and the present invention has been reached.

Next, the present invention will be described in detail.

The rubber composition for a vibration damping material of the present invention is obtained by using polynorbornene and halogenated butyl rubber.

The above polynorbornene is generally produced by ring-opening polymerization of norbornene synthesized from ethylene and cyclopentadiene by the Diels-Alder reaction. This polymer has a glass transition temperature of 3
At 5 ° C., it is a resin at room temperature or a powder obtained by pulverizing this. Then, it is usually used as a norbornene rubber by adding a softening agent such as petroleum-based oil to the rubber to make it rubber.

The halogenated butyl rubber used together with the above-mentioned raw materials is not particularly limited, and conventionally known ones can be mentioned. Among them, chlorinated butyl rubber is preferably used.

The mixing ratio of the halogenated butyl rubber (A) and the polynorbornene (B) is A / B = 2.
It is preferable to set the ratio to 5 to 10. Particularly preferably, A / B = 4 to 7. That is, when the mixing ratio (A / B) is less than 2.5, there is a tendency that the peak of the loss coefficient on the low temperature side is not formed and only one peak of the high temperature side is formed. On the contrary, if the blending ratio exceeds 10, the loss coefficient on the high temperature side tends to be small, and the damping property cannot be expected.

In the rubber composition for vibration damping materials of the present invention, a reinforcing agent, a filler, a softening agent, a vulcanizing agent and the like are appropriately blended in addition to the above-mentioned raw materials.

The above-mentioned reinforcing agent is used to increase the hardness and tensile strength of the vibration-proof rubber, and generally carbon black is used. In addition to these, white carbon, clay and the like can be used, and they can be used alone or in combination. Most preferred is carbon black.

The above-mentioned filler is used for the purpose of improving the workability of the anti-vibration rubber, and examples thereof include barium sulfate and calcium carbonate. These may be used alone or in combination. Particularly in a composition containing polynorbornene as a main component, it is preferable to use barium sulfate as a filler.

The above-mentioned softening agent is used mainly for the purpose of making the polynorbornene rubber.
As described above, the polynorbornene becomes rubber by absorbing this softening agent. Examples of such a softening agent include procell oil fractionated from petroleum and plant-based softener, and it is preferable to use process oil for the rubber composition for vibration damping materials.

The rubber composition for a vibration damping material of the present invention can be manufactured using the above-mentioned raw materials, for example, as follows. That is, the above-mentioned respective raw materials can be blended in a predetermined ratio and mixed in a mixer to form a sheet. The rubber composition for a vibration damping material thus obtained is in the form of a sheet, and by molding and vulcanizing the rubber composition, a vibration damping rubber having a predetermined shape can be produced.

In this case, the mixing ratio of each of the above raw materials is usually set as follows. That is, with respect to 100 parts by weight of polynorbornene (hereinafter abbreviated as "part"), 30 to 200 parts of a reinforcing agent such as carbon black, 100 to 400 parts of a filler such as barium sulfate, and 100 parts of a softening agent such as process oil are used. It is preferable to set the ratio to about 200 parts.

[0018]

As described above, since the rubber composition for damping material of the present invention contains halogenated butyl rubber in the low impact resilience rubber composition containing polynorbornene as a main component, the peak loss coefficient is obtained. Is formed not only in the temperature region near room temperature but also in the low temperature region, and has a double peak shape. Further, the increase in elastic modulus is suppressed in the low temperature region, and the brittle fracture temperature exists at a temperature lower than that in the low temperature region in the practical range. As a result, by using this, it becomes possible to manufacture a vibration damping rubber that exhibits high damping performance near room temperature and exhibits good vibration damping characteristics in a wide temperature range from low temperature to around room temperature. Therefore, the above-mentioned anti-vibration rubber can be used as an anti-vibration rubber for electric parts, mechanical parts, buildings, etc., and can achieve almost complete anti-vibration in a wide temperature range including room temperature as well as low temperature range. , Is an excellent damping material.

Next, examples will be described together with comparative examples.

[0020]

Examples 1 to 4 The raw materials shown in Table 1 below were blended in the proportions shown in the same table, blended by the above-described method and mixed to obtain a sheet-shaped rubber composition for a vibration damping material. Next, mold it,
A vibration proof rubber was made by vulcanization, and the properties of the vibration proof rubber were measured and shown in the same table.

[0021]

[Table 1]

* 1: Exxon chlorobutyl 1066 manufactured by Exxon Chemical Co. was used. * 2: Measured at a frequency of 100 Hz using a spectrometer manufactured by Yokohama System Co., Ltd. * 3: E ₁ is the storage elastic modulus, E ₁ at 0 ° C. indicates the storage elastic modulus at 0 ° C., and E ₁ at 20 ° C. indicates the storage elastic modulus at 20 ° C. Therefore, E _{1 at} 0 ℃ / E _{1 at} 20
C indicates the ratio of the storage elastic modulus at 0 ° C to the storage elastic modulus at 20 ° C.

[0023]

[Comparative Examples 1 and 2] The raw materials shown in Table 2 below were blended in the proportions shown in the same table, blended by the above-mentioned method and mixed to obtain a sheet-shaped rubber composition for a vibration damping material. Next, mold it,
A vibration proof rubber was made by vulcanization, and the properties of the vibration proof rubber were measured and shown in the same table.

[0024]

[Table 2]

* 1: Exxon chlorobutyl 1066 manufactured by Exxon Chemical Co. was used. * 2: Measured at a frequency of 100 Hz using a spectrometer manufactured by Yokohama System Co., Ltd. * 3: E ₁ is the storage elastic modulus, E ₁ at 0 ° C. indicates the storage elastic modulus at 0 ° C., and E ₁ at 20 ° C. indicates the storage elastic modulus at 20 ° C. Therefore, E _{1 at} 0 ℃ / E _{1 at} 20
C indicates the ratio of the storage elastic modulus at 0 ° C to the storage elastic modulus at 20 ° C.

FIG. 1 shows the results of measurement of the loss coefficient of the antivibration rubbers of the above-mentioned examples and comparative examples. In FIG. 1, curves A to D correspond to Examples 1 to 4, and curves E and F correspond to Comparative Examples 1 and 2. Curve A ~
As is clear from the comparison between D and the curves E and F, and from the results in Tables 1 and 2 above, the loss coefficient peaks were formed at two locations near the low temperature and room temperature in the temperature-loss coefficient curve in the example product. There is. On the other hand, the comparative example products E and F had only one peak of the loss coefficient formed near room temperature. From this, it is understood that the products of Examples have excellent vibration damping properties in a wide temperature range from a low temperature region to around room temperature. Further, it is understood that the brittle fracture temperature is also set to a lower temperature side, the brittle fracture does not occur in the practical temperature range, and the increase in elastic modulus is suppressed.

[Brief description of drawings]

FIG. 1 is a curve diagram showing a temperature-loss coefficient relationship.

Claims (2)

[Claims] 1. A rubber composition for a vibration damping material, characterized in that a halogenated butyl rubber is blended with a low impact resilience rubber composition containing polynorbornene as a main component. 2. The compounding ratio of halogenated butyl rubber (A) and polynorbornene (B) is A / B = 2.5 by weight ratio.
The rubber composition for a vibration damping material according to claim 1, wherein the rubber composition is set to 10.