JPS58180538A - Vibration-proof and soundproof rubber composition - Google Patents

Abstract

PURPOSE:To provide a rubber compsn. having excellent vibration-proofness and soundproofness, by blending additives with a specified styrene/butadiene copolymer rubber and vulcanizing the mixture with sulfur. CONSTITUTION:Not more than 200pts.wt. carbon black, 1-30pts.wt. zinc white, 0.1-10pts.wt. stearic acid as additives and, if necessary, at least one rubber selected from natural rubber, diene rubber, etc. are blended with 100pts.wt. styrene/butadiene copolymer rubber having a Mooney viscosity ML1+4 (100 deg.C) of 30-40, a bonded styrene content of 15-30wt% and a Williams recovery rate (25 deg.C) of 3.5-4.2mm.. The mixture is vulcanized with sulfur by a conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber composition with excellent vibration and soundproof properties.

In recent years, there has been a rapid development of automatic cars, and cars with less vibration and noise are desired, especially from the viewpoint of ride comfort.

In order to satisfy these demands regarding anti-vibration rubber for automobiles, especially engine mounts, it has been awaited to develop a combination that simultaneously satisfies both anti-vibration and sound-insulating properties, which have been lacking in the past.

Until now, there has been no polymer for anti-vibration rubber that has both anti-vibration and sound-insulating properties, and polymers with excellent anti-vibration properties have poor sound-insulating properties, and conversely, polymers with excellent sound-insulating properties have poor anti-vibration properties. It is known that vibration-proofing properties and sound-proofing properties are contradictory to each other, such that they are inferior to each other. Therefore, when emphasis is placed on vibration-proofing properties, it is necessary to sacrifice soundproofing properties, and conversely, when emphasis is placed on soundproofing properties, vibration-proofing properties have to be sacrificed. For this reason, natural comb has traditionally had excellent soundproofing properties.

Previously, we had been content to use a blend of polybutadiene and styrene-butadiene copolymer, which has excellent vibration-proofing properties, but this was not compatible with the recent second wave, and the development of new technology is awaited. Ta.

In view of such a lumpy state, the inventors of the present invention have continued to conduct intensive studies in order to develop a rubber composition that is excellent in both vibration-proofing properties and sound-proofing properties.

Mooney viscous jet ("L1+4) is 30-40. Amount of bound styrene is 15-30 weight g1. Williams recovery rate (25
A rubber composition was discovered by blending an auxiliary material with a styrene-butadiene copolymer having a temperature (°C) of 3.5 to 4.211 and exhibiting excellent vibration-proofing properties and sound-proofing properties due to sulfur erosion. The present invention has now been completed.

Here, the Williams recovery rate is ASTMI J926-
It indicates the degree of plasticity of the polymer alone or an unvulcanized rubber compound described in No. 67, and it is correlated with the presence or absence of monobranching.
It has been found that polymers having no single branch exhibit a tendency opposite to that of polymers having no single branch.

To explain the vibration isolation and sound insulation properties based on the dynamic properties of vulcanized rubber, the relationship between the vibration transmission rate of the vibration isolation rubber and the vibration frequency ω of the excitation force is expressed by the following equation (1) from a one-dimensional vibration system. become that way.

However, "n: Heavy duty of the support. Kp: Dynamic spring constant - δ: Loss coefficient. In engine mounts for automatic umbrellas, the vibration frequency is 10~
In the 20Hz region, vibration isolation is important.

Further, in a region where the vibration frequency is 75 Hz or higher, soundproofing is important. Therefore, in order to obtain an engine mount that is excellent in both vibration and soundproof characteristics, it is preferable that the vibration transmission coefficient τ is small in all regions.

It follows that a formulation with -δ as large as possible and with D as small as possible is good.

That is, as shown in FIG. 1, conventional rubber such as natural rubber,
Rubber compositions such as diene thread rubber and diene thread copolymer rubber cannot exhibit the characteristics shown by the points above, and may not be suitable for rubber blend systems or for auxiliary materials such as carbon black and fordifiers. Depending on the selection of type and amount (that is, the formulation), only uniform results can be obtained.

However, only the snare-gtadiene copolymer rubber with branches in its skeleton behaves differently from other rubbers, and 1i
ft. Find out that it deviates from the straight line 4.

By reducing the total number of branches and increasing the number of two branches and the length of the branches, an excellent balance between the insulation and sound insulation properties, which is indicated by the point on the straight line fBl in Figure 1, can be achieved. A rubber composition was obtained.

The styrene-butadiene copolymer rubber in the present invention has a molecular weight of 3 at Mooney viscosity IML1++ (100°C).
0-40. It is preferable to have a branched skeleton in which the bound styrene content is 15 to 30% by weight and the Williams recovery rate (25°C) is 3.5 to 4.2M.

If the molecular weight is larger than the above range, the anti-vibration properties will be poor.

If it is small, it exhibits liquid rubber-like properties and has practical problems such as vulcanization problems. Further, if the amount of bound styrene is greater than the above range, it exhibits dendritic properties and has poor soundproofing properties, and if it is smaller than the above range, it has poor vibrationproofing properties. Furthermore, if the Williams recovery rate is larger than the above range, vulcanization will occur between the branches, and the Shibahashi density will tend to increase, resulting in poor vibration-proof mechanical properties. It will show characteristics similar to those that do not.

Therefore, if a styrene-butadiene copolymer rubber having the above-mentioned content M is used, it is possible to obtain a composite product that is said to have a balance of both vibration-proofing and sound-proofing properties that could not be achieved with conventional formulations. and its practical advantages are a great book.

In the present invention, the method for producing the branched styrene-9-noxone copolymer rubber includes styrene.

Each of the seven polymers of Y- and Q-ene is reacted with a branching agent (e.g., divinylbenzene) in an organic solvent in the presence of an alkali metal catalyst.
14 can be easily obtained by adding f and polymerizing.

In the present invention, the rubber used by blending with the branched styrene-butadiene copolymer rubber and L7 include natural rubber, diene thread rubber (for example, butadiene rubber, styrene-butadiene copolymer rubber, chlorolune rubber, isoprene-isobutylene copolymer rubber, There are rubbers such as polymerized pseudo rubber).

In addition, f, t as auxiliary materials used in the present invention
4. Commonly used materials can be used, and some of the auxiliary materials include carbon black, iL stearic acid, etc., and vulcanization accelerators, sulfur, etc.

The amount of compounding is 2 for 100 parts by weight of rubber, 200 parts by weight for carbon black, and 1 to 3 parts for zinc white.
0 vehicle weight parts, stearic acid sinter o, i-i.

Parts by weight, along with 1 tube of softening agent, inorganic white light agent, wax, anti-aging agent, and scorch inhibitor, if necessary.
It does not mean that it can be blended in an appropriate amount within the commonly used range.

The composite material containing the additive materials in this way is vulcanized with sulfur according to the conventional method. A sticky rubber composition can be obtained.

5) below! The present invention will be described in detail by showing examples and comparative examples, but it is not intended that the scope of the present invention be limited to these examples.Example 1 Mooney viscosity ML ++4 (100 ℃) 31. Bonded steel V:/amount 25% by weight, William rotation ffl rate (25°C)
100 parts by weight of styrene-butadiene copolymer rubber having a branching of 3.7M, 50 parts by weight of FEF carbon, 30 parts by weight of naphthene oil, 51 parts by weight of zinc white, 1 part by weight of stearic acid and 2+ parts by weight of anti-aging agent. The mixture was kneaded using a B-type Banbury to form a carboxylic acid. After this master patch was left to stand for 2 hours and cooled, 1.5 parts by weight of sulfur, 3 parts by weight of promoter Oz, and 0.3 parts by weight of promoter ~18N were added and mixed using an 8-inch roll.

This compound was press-vulcanized at 150° C. for the optimum vulcanization time using a rheometer to obtain a vibration-proof rubber sample (10) shown in FIG. In addition, when compounding, the performance of the anti-vibration rubber was taken into consideration, and the static spring constant Ks of the vulcanizate was adjusted to approximately 30 #f/- by Jido Carbon Co., Ltd.

Next, the anti-vibration rubber properties were determined using a hydraulic servo type dynamic property testing machine (Saginomiya Manufacturing Co., Ltd. ALL). That is, using the vibration-proof rubber sample (10) produced by press vulcanization,
Find the ridge spring constant KS, and further @spring constant KD#'1
The value of lOOHz and the loss coefficient -δ were determined from the 15 Hz test, and the total groove @ l, , K n /K s value was taken as the soundproofing property.

The smaller the value of Kn/Ks, the better the soundproofing properties, and the larger the value of -δ, the better the vibration isolation P↓. The results are shown in Table-1.

Compared to Comparative Example 1 (excellent in vibration-proofing properties but poor in sound-proofing properties) and Comparative Example 2 (good in sound-proofing properties but poor in vibration-proofing properties) described later, this compound has a good balance between vibration-proofing and sound-proofing properties. It was recognized that the properties were well-balanced and were sufficiently good for practical use.

On the other hand, a vibration fatigue test was conducted using the same sample.

The test conditions were an initial V position of 10% in the r direction, a stroke of ±811, and a rotation speed of 50 Q rpm, and it was confirmed that the number of vibrations in the trench where the crack remained was more than 100,000 times, and that there was no break in practical use. 'IJ. In addition, in Figure 2, (n)
(x2) indicates H mounting bolts.

Example 2 Mooney viscosity ML1+4 (100°C) 33. Conjugated Sunalene t25 weight fi%, Williams recovery''m (25℃)3
．． The same formulation as in Example 1 was applied to 100 parts by weight of a branched styrene-butadiene copolymer rubber of 9 JEi, and the same experiment f as in Example 1 was repeated. The results are shown in Table-1. As is clear from the results in Table 1 (/(-.

This compound was also found to be excellent enough to be put to practical use, with a well-balanced combination of vibration-proofing and sound-proofing properties. A blend system of 60 parts by weight of butadiene copolymer rubber and 40 parts by weight of natural rubber was used, and the same liNM as in Example 1 was repeated except for the above. ° Based on the results in Table 1, the characteristics of natural rubber can be determined from cows and 1. The objective was to obtain a composition 1 which has a balance between both vibration-proofing properties and sound-proofing properties, and has an IPf' value sufficiently suitable for practical use.

Blends of bulk rubber, which have excellent mechanical properties and durability, are very advantageous.

Example 4 The blend system of Volume Market Example 3 was used, with 58 parts of FEF carbon, 35 parts of naphthenic oil, and 4 parts of naphthenic oil.
! From the results shown in Table 21, in which the same material as in Broom Example 1 was repeated 7 times, it was possible to obtain an excellent composition with well-balanced properties of both vibration-proofing and sound-proofing properties, which was sufficiently suitable for practical use.

Comparative Example 1 The polymer with the formulation of Example 1 had a Mooney viscosity of ML1+4 (
100℃)52. Bound styrene content: 23.5% by weight.

The styrene-1-Tazine copolymer rubber ioo layer has a Williams recovery rate (25° C.) of 2.811.

The same experiment as in Example 1 was repeated in another 1i dormitory. As is clear from the results in Table 2, it was found that although Vi was excellent in vibration damping properties, it was inferior in sound proofing properties.

Comparative Example 2 Polymer with the formulation of Example 1 has a Mooney viscosity of ML1+4
(100℃)45. The amount of bound styrene is 25% by market weight.

Styrene-butadiene copolymer rubber with a Williams recovery rate (25°C) of 2.6 IIm and 100 parts.

Otherwise, the same experiment as in Example 1 was repeated. As is clear from the results in Table 2, although the soundproofing properties are superior to those of Comparative Example 1, the vibrationproofing properties are poor, and there are problems with the balance between these two properties as a practical VC.

Comparative example 3 Actual bar example 1? 'L+' joins polymer to natural rubber toot
The same experiment as in Example 1 was repeated except for the following parts.

As is clear from the results in Table 2, although the soundproofing properties are very good, the vibrationproofing properties are extremely poor and the book cannot be used practically in terms of the balance between the two properties.

Table-1 Table-2 Figure 1 Figure 2 Procedural Amendment 111 (Method) Patent Office Immersion Room Display of Kazuo Wakasugi 1 Case Patent Application Nos. 1983-64564 & Person Making Amendment Relationship with Case Patent Applicant ↓ Amendment Order Date 6 Amendment (1) The following words are added after the table in Table 2 on page 13 of the specification. That is,

[Brief explanation of the drawing]

FIG. 1 shows tan δ on the horizontal axis and KD/
FIG. 2 is a graph illustrating a vibration-proof rubber sample. 10... Anti-vibration rubber sample, 11... Metal fitting, 12...
Mounting bolt patent applicant

Claims (2)

[Claims] (1) Mooney viscosity ML I+4 (100°C); 30
~40° Amount of bound styrene: 15-30% by weight, Williams compound ratio (25°C): 3.5-4.2N styrene-butadiene co-rectangular composite rubber is blended with auxiliary materials, and sulfur vulcanized. An anti-vibration and sound-insulating rubber composition characterized by a vibration-proof and sound-proof rubber composition. (2) The vibration damping device according to claim (1), wherein at least one rubber selected from natural rubber, diene thread rubber, etc. is blended with the styrene-butadiene copolymer rubber. Soundproof rubber composition.