JPS6195048A - Damping material - Google Patents

Abstract

PURPOSE:A damping material that is obtained by vulcanizing and forming a rubber composition containing an extender oil with a viscosity/density ratio of more than a specific value and fillers, thus showing a large hysteresis loss, reduced temperature dependency and high strength at breakage. CONSTITUTION:The objective damping material is obtained by adding, to 100pts. wt. of a rubber component, preferably a styrene-butadiene rubber or natural rubber, (B) 20-200pts.wt., preferably 30-150pts.wt. of an extender oil which has a viscosity/gravity constant (V.G.C.) of more than 1, preferably 1.05-1,300 according to the equation (G is specific gravity at 60 deg.F; V is dynamic viscosity at 210 deg.F), an acid value of less than 80 and more than 60 deg. of aromatic hydrocarbon content and (C) 20-200pts.wt., preferably 30-150pts.wt. of a filler, preferably carbon black and (D) 7 or less pts.wt. of a rubber vulcanizing agent such as sulfur or organic preacid and forming the resultant composition.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field! The present invention relates to a vibration isolating material that has a large hysteresis loss, a small temperature dependence of the hysteresis loss, and an excellent breaking strength.

"Prior Art" In recent years, there has been a demand for rubber materials with excellent anti-vibration or vibration-damping properties in order to prevent noise and vibration from means of transportation such as automobiles and motorcycles, as well as from industrial machinery. Since these vibration isolating or damping materials are used under extremely harsh conditions, so-called tough materials with large hysteresis loss and excellent fracture properties are required.

Conventionally, materials used to meet these demands include natural rubber or synthetic rubber mixed with a large amount of oil or carbon black, or blended with a polymer having a relatively high glass transition temperature (Tg).

has been used.

Generally, when oil is blended, the impact resilience is reduced and vibration damping properties are improved, but compression set and fracture properties are reduced.

Furthermore, if a large amount of carbon black is used, the processability during kneading and molding and the heat generation properties of the vulcanizate will deteriorate. Further, when a polymer having a relatively high (Tg)Q is blended, there is a drawback that the temperature dependence of hysteresis loss is large and low-temperature properties are poor.

On the other hand, when looking at the practical conditions of vibration-proofing materials, the operating temperature ranges over a wide range, and as a result, vibration-proofing rubber materials with low temperature dependence of hysteresis loss are required.

"Problems to be Solved by the Invention" The object of the present invention is to have good fracture characteristics, large hysteresis loss, and high hysteresis loss without reducing workability during kneading and molding. An object of the present invention is to provide a vibration isolating material with low temperature dependence of loss.

According to the present invention, 20 to 200 parts by weight of extender oil and 20 to 200 parts by weight of reinforcing filler are blended as essential components to 100 parts by weight of the rubbery component, and General formula (1
) viscosity specific gravity constant (V, G, C,) is 1.00
There is provided a vibration damping material obtained by vulcanizing and molding a rubber composition characterized by the above characteristics.

(In the formula, G represents the specific gravity of the extender oil at 60"F, and ■ represents the kinematic viscosity of the extender oil at 210@F.) The extender oil of the present invention can be added to rubber in a solution or lamex state, or A method of adding it at the time of compounding is used.

The extender oil of the present invention has V, G, and C of 1.00 or more, preferably 1.05 to 300. V.G.

When C0 is less than 1.00, the hysteresis loss is small and the temperature dependence of the hysteresis loss is large. Further, the acid value of the extender oil used in the present invention is preferably 80 or less, and the aromatic carbon content contained in the extender oil is preferably 60°.
That's all.

The amount of extension oil added in the present invention is 20 to 200 parts by weight, preferably 30 to 150 parts by weight, per 100 parts by weight of the rubbery component.
Parts by weight range. If it is less than 20 parts by weight, hysteresis loss will be unsatisfactory, and if it exceeds 200 parts by weight, fracture properties and compression set will be poor.

Carbon black is preferably used as a filler.
- The blending amount is in the range of 20 to 200, preferably 30 to 150 parts by weight per 100 parts by weight of the rubbery component. If it is less than 20 parts by weight, the effects of the present invention cannot be obtained, and if it exceeds 200 parts by weight, kneading processability and rubber elasticity cannot be obtained.

Rubber components used in the vibration damping material of the present invention include natural rubber, polyisoprene rubber, styrene-butadiene rubber,
Diene rubbers and olefin rubbers such as butadiene rubber, ethylene propylene rubber, and butyl rubber are used. Preferred rubbery components are styrene-butadiene rubber, natural rubber.

Further, the vibration damping material of the present invention can be obtained by adding 7 parts by weight or more of sulfur or organic peroxide as a normal rubber crosslinking agent to 100 parts by weight of the rubbery component, and then molding the material. can. Furthermore, other extender oils, processing aids, anti-aging agents, and other compounding agents that are usually blended into rubber can be added to the vibration damping material. There are no particular restrictions on the types and amounts added, and they may be determined as necessary.

The vibration isolating material of the present invention can be suitably used as a vibration isolating material for various products including cars by taking advantage of its characteristics.

"Examples" Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1-4, Comparative Examples 1-3 Table 1 shows the formulations of Examples and Comparative Examples.

The units of numbers in the table are parts by weight.

After kneading was carried out in a small Banbury mixer using the formulation shown in Table 1, press vulcanization was carried out at 145°C for 60 minutes.

×1 extension oil-A: V, G, C, = 1.05, acid value =
2. Aromatic hydrocarbon content = 60% or more.

1/-B: n=l, 13, 〃=λ
〃=〃II-C: n=1.15, 〃=
2, 〃=〃II −D: II =0.
83. 11 = O, OL, 〃 ; 6%.

*2 81ONA: N-phenyl-N'-isopropyl-P-phelenediamine *3 CZ:
N-cyclohexyl-2-benzothiazolyl-benzoamide*4M: 2-mercaptobenzothiazole*5D
: 1.3 diphenylguanidine *6 SBR: 2 containing styrene obtained by emulsion polymerization
3.5%, Mooney viscosity ML (144,100°C) = 1
60).

*7 SBR: 2 containing styrene obtained by emulsion polymerization
3.5%, Mooney viscosity ML (1+4,100°C) = 1
00).

A tensile test was conducted according to the second surface strength tester 6301. The results are shown in Table 2.

Hysteresis loss characteristics were evaluated by measuring tan δ using a mechanical spectrometer.

The example has a large hysteresis loss and a small temperature dependence of the hysteresis loss, and is suitable as a vibration isolating material.

In addition, Examples 2 to 4 and Example 6 have better fracture characteristics than Comparative Example 3. Comparative Examples 1 and 2 are unsatisfactory in terms of vibration damping characteristics because the hysteresis loss is smaller than in the example, and the temperature dependence of the hysteresis loss is large.

"Effects of the Invention" The present invention is a new vibration damping material containing high V, G, and C extension oils, and has a large hysteresis loss and temperature dependence compared to conventional vibration damping materials. It is small in size and has excellent breaking properties, so it can be suitably used as various vibration isolating materials.

Claims (1)

[Claims] (1) Per 100 parts by weight of the rubbery component, add 20 to 200 parts by weight of an extender oil having a viscosity specific gravity constant (V.G.C.) of 1.00 or more according to the general formula (1), and a filler. 20
A vibration damping material made by vulcanizing and molding a rubber composition containing ~200 parts by weight. V. G. C. = {G+0.0887-0.776log
log(10V-4)}/{1.082-0.72lo
glog(10V-4)}...(1) (wherein, G is 6
Specific gravity at 0°F; V represents kinematic viscosity at 210°F. )