JPH03106949A - Vibration-proofing and damping rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition improved in vibration-proofing and damping performances by decreasing the frequency dependence in the low-frequency region to the high-frequency region by adding a specified inorganic filler to a polymer prepared by mixing natural rubber and/or isoprene rubber with PVC. CONSTITUTION:Natural rubber and/or isoprene rubber is mixed with plasticized PVC in a ratio of (70-30)/(30-70) to obtain a polymer (A). Separately, an SiO2 component is mixed with an Al2O3 component or an MgO component to obtain an inorganic filler (B). 100 ptswt. component A is mixed with 20-200 pts.wt. component B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vibration damping rubber composition, specifically a blend of one or two of natural rubber and isoprene rubber and polyvinyl chloride. It has a large loss coefficient in the low frequency range, small frequency dependence from the low frequency range to the high frequency range, and has a low dynamic elastic modulus at high frequencies and a small static-dynamic ratio, making it an excellent vibration damping effect. The rubber composition is then opened.

(Prior art) Regarding the vibration transmissibility, which generally indicates the performance of anti-vibration rubber,
It is well known that there is a predetermined opening equation between the vibration transmissibility T and the frequency ω of the excitation force using a degree-of-freedom model.
From this relational expression, in the region where the frequency ω of the excitation force is small, T = 1 /tan δ− − − − (1) Also,
In the region where the excitation frequency is large, T = Kd/(mω2-Kd) (2) (where Kd is the dynamic modulus of elasticity, tanδ is the loss coefficient, and m is the weight of the support). shown.

That is, it can be seen that materials with excellent vibration damping properties have a large tan δ and a small dynamic elastic modulus.

By the way, the anti-vibration rubber generally used for vehicles etc. has a rating of 10
In the low frequency range of ~20 (Hz), it has vibration damping to suppress shake phenomena, etc., and on the other hand, in the high frequency range of 75Hz or higher, it requires soundproofing to suppress indoor muffled sounds, etc.
It is said that the ideal state is that tan δ is large in the low frequency region, and the static-dynamic ratio (dynamic spring constant/static spring constant) is small in the high frequency region.

For this reason, conventionally, blends of natural rubber or polybutadiene rubber, which have excellent soundproofing properties, and styrene-butadiene copolymers, which have excellent vibrationproofing properties, have been used. In particular, polybutadiene having a cis-1,4 bond content of 80% or more, an average chain length of 1,4 bonds of 110 to 450, and a ratio of weight average molecular weight to number average molecular weight of 8 or more is used in natural rubber or synthetic rubber. A blend of diene rubber containing isobrene as a main component is known.

(Problems to be Solved by the Invention) However, conventional anti-vibration rubber compositions also lack a balance between vibration-proofing and sound-proofing properties, and with the development of the automobile industry, etc. The target value of the vibration absorption properties required for vibration damping has become stricter year by year, and there has been a desire to develop even better vibration damping rubber compositions.

The present inventors have developed a vibration-damping rubber composition that has a large loss coefficient at low frequencies, has little frequency dependence from the low frequency region to the high frequency region, has a small dynamic elastic modulus at high frequencies, and has a small static-dynamic ratio. As a result of the aim of developing products, S
It was discovered that a rubber composition with excellent vibration damping performance can be obtained by mixing a two-component inorganic filler containing Al203 or MgO in IO2 or a three-component inorganic filler containing A1203 and MgO in Sto2. Ta.

(Means for Solving the Problems) In order to achieve the above object, the anti-vibration rubber composition of the present invention is made by blending one or two of natural rubber and isoprene rubber with polyvinyl chloride. A two-component inorganic filler consisting of an SIO2 component and an AI2O3 component or MgO component is mixed into the polymer.

In addition, in the present invention, SiO2 component and A
It is also possible to use a three-component system containing an 12O3 component and a MgO component.

According to the anti-vibration rubber composition of the present invention, one or two of natural rubber and isoprene rubber are blended with polyvinyl chloride, and S! Al2 in the 02 component
By filling the inorganic filler with a two-component system consisting of the 03 component or the MgO component, or a three-component system containing all of these components, the resulting rubber composition has a large loss coefficient (tan δ) in the low frequency region. , and has a small frequency dependence, and has characteristics such as a small dynamic elastic modulus and a small static-dynamic ratio in the high frequency region, and has an extremely excellent vibration damping effect.

The polymer used in the anti-vibration rubber assembly of the present invention is a blend of natural rubber and/or isoprene rubber and polyvinyl chloride, and the blend ratio (weight ratio)
rubber/polyvinyl chloride 70/30~30/70
is within the range of When the blend ratio of rubber/PVC is in the range of 100/0 to 80/20, low frequency (1 to IOH
Z), the loss coefficient (tanσ) is small, while in the range of 20/80 to 0/100, the frequency dependence of tanδ is large and the static-dynamic ratio becomes large, which makes it difficult to achieve the desired vibration and sound insulation properties. The rubber composition does not have

The natural rubber or isoprene rubber used here is commonly used, and the polyvinyl chloride has a degree of polymerization within the range of 800 to 3000 and is a linear or craft polymer. There is. In addition, polyvinyl chloride contains various plasticizers such as DOP, and the amount added is 1% to 1% of polyvinylchloride.
Further, the two-component or three-component inorganic filler used in the present invention is a two-component inorganic filler in which an A I 203 component or a MgO component is mixed with two SIO components. system or S
It is a three-component system in which an iO2 component, an AI203 component, and a MgO component are mixed. For example, as a two-component system, dexyclay (S i 0244%-AI203 39
%) Manufactured by Vanderbi It, Talc (5102
64%-Mg0 32%), Catalbo (SiO:z
88.9%-AI203 6.5%), Neosuper (5102 57.7%-A1203 28.9
%) Manufactured by Seto Ceramic Materials Co., Ltd., Mica (5102 46%-
A1203 38%), etc., and silcalite (SiO■ 40.8%-A1203) as a three-component filler.
24.4%-Mgo23.4%) manufactured by Takehara Chemical Industry Co., Ltd., etc.

The amount of this filler is 20 to 20 parts by weight per 100 parts by weight of the polymer.
0 parts by weight are mixed. If it is less than 20 parts by weight, the loss coefficient will be small and the vibration damping properties will be poor. On the other hand, if it exceeds 200 parts by weight, the static-dynamic ratio increases and the vibration damping properties deteriorate.

Furthermore, carbon black is used as another filler in the present invention. Carbon black is not particularly limited, but has an average particle diameter of 30 to 120 nm, preferably 50 nm.
~100 nm is preferable. Examples thereof include commonly used furnace blacks, acetylene blacks, thermal blacks, channel blacks, and the like. This carbon black is filled in an amount of 30 to 70 parts by weight per 100 parts by weight of a polymer made of a blend of natural rubber and/or isoprene rubber and polyvinyl chloride.

If carbon black having an average particle diameter of less than 3 Q nm is used, the reinforcing properties of the rubber composition tend to become too high, and the dynamic elastic modulus particularly in the high frequency range (70 to 1001 {Z) tends to increase. On the other hand, if carbon black with an average particle diameter exceeding 120 nm is used, low frequency range (120 nm
~10Hz) becomes smaller. Furthermore, if the amount of carbon black charged is less than 30 parts by weight, the loss coefficient in the low frequency range will be small, and if it exceeds 70 parts by weight, the dynamic elastic modulus in the high frequency range will tend to be large.

In addition, the anti-vibration rubber composition of the present invention is formulated with softeners, anti-aging agents, vulcanization aids, vulcanization accelerators, etc. used in ordinary rubber, and is vulcanized or shaped into anti-vibration rubber compositions. In this case, the method of mixing each component is not particularly limited, and the components can be kneaded and formed into a sheet by appropriate known means and methods using, for example, a Banbury mixer, kneader, roll, etc.

(Example) Next, the present invention will be explained in more detail using specific examples.

The dynamic elastic modulus E゛ and the loss coefficient tan δ were measured using a rheolograph solid manufactured by Toyo Seiki ■ at a measurement temperature of 25
℃±2℃, 0.05 to 0 at frequency 1 to IOOHZ
．． The measurement was performed by applying a sinusoidal strain of 0.08% to the sample.

Example 1 / Comparative Example 1 Based on the formulation shown in Table 1, the rubber compound was kneaded with a Banbury mixer, then shaped into a sheet using a roll, or 15
Vulcanize at 0℃ for 20 minutes, and make a 2mm thick x 8mm wide x 2 long pieces.
Various samples with a diameter of 0 mm were prepared. For these materials, dynamic elastic modulus (E' (IHz, 100Hz)), dynamic elastic modulus ratio (E' (100}1z) /E' (IH
z)), loss coefficient tanσ(IHz, 100Hz)
and loss factor ratio (tanσ(100Hz)/ta
n 6 (IHz)) was measured, and the results are also listed in Table 1.

Comparative Example 1-1 filled with single-component CaCo3 and Comparative Example 1-2 filled with single-component Sl02 have a small IHz tan δ and a large dynamic elastic modulus ratio, and both can be used as vibration damping materials. Undesirable. Si02・MgO or S
Example 1-1 filled with two-component system of IO2/A1203
, 1-2 have a large tan δ at lHz and a small loss coefficient ratio, so they have excellent vibration damping effects from low frequency ranges to high frequency ranges.

Example 2/Comparative Example 2 Based on the formulation shown in Table 2, a measurement sample was prepared in the same manner as in Example 1, and the dynamic elastic modulus E' (IHz, 100H
z), dynamic elastic modulus ratio E''(100Hz)/E' (IH
z), loss coefficient tan δ (IHz, 100 Hz) and loss coefficient ratio tan δ (100 Hz) / tan δ (I
Hz)lir: The results are also listed in Table 2.

Comparative examples 2-1 and 2-2 filled with titanium oxide and iron oxide
, 2-3 have a small 1Hz jan6 and are not preferred as vibration damping materials. Si02・AI203・Mg
Example 2-3, which uses a filler based on a three-component system of O, has a low dynamic elastic modulus ratio and a large tan δ, and has very good characteristics of a vibration damping material. . Also, 5
Example 2 based on two-component system of 102/A1203
-1, 2-2, 2-4, 2-5, and 2-6 have some dynamic elastic modulus ratios that are larger than those of the comparative examples, but tan δ is large and they have good characteristics. I understand.

Below blank Example 3 Si02/AI on NR/PVC=50/50 polymer
A measurement sample was prepared in the same manner as in Example 1 using a filler based on a two-component system of No. 203 based on the formulation shown in Table 3, and the dynamic elastic modulus E' (IT{z,IOOHZ), Dynamic elastic modulus ratio E"(100Hz)/E"(IHz)
, loss coefficient tan δ (IHz, 100 Hz) and loss coefficient ratio jan6 (100 Hz) / tan 6 (
IHz) was measured, and the results are also listed in Table 3.

The results show that as the amount of filler mixed increases, the loss coefficient increases and the damping performance becomes superior. In addition, the loss coefficient changes little with frequency, making the material excellent in vibration damping effects from low to high frequency ranges.

Margin below? Effects) As described above, the anti-vibration rubber composition of the present invention is a blend of one or two of natural rubber and isoprene rubber and polyvinyl chloride, and contains Al2 in the SiO2 component.
The inorganic filler is filled with a two-component system in which an O3 component or an MgO component is mixed, or a three-component system in which the S10■ component is mixed with an A]2O3 component and an MgO component. It is a material with excellent vibration damping effect, which has a large tan6 and a small frequency dependence from low frequencies to high frequencies, and has a small E" at high frequencies.

Claims (1)

[Claims] 1. A polymer made by blending one or two of natural rubber and isoprene rubber with polyvinyl chloride, SiO_2 component, Al_2O_3 component or Mg
An anti-vibration rubber composition comprising a two-component inorganic filler mixed with an O component. 2. A 3-component inorganic filler in which SiO_2 component, Al_2O_3 component and MgO component are mixed is mixed into a polymer that is a blend of one or two of natural rubber and isoprene rubber and polyvinyl chloride. An anti-vibration rubber composition characterized by: 3. The anti-vibration rubber composition according to claim 1 or 2, wherein the two-component or three-component inorganic filler is added in an amount of 20 to 200 parts by weight per 100 parts by weight of the polymer. 4. Any one or two of natural rubber and isoprene rubber and polyvinyl chloride are mixed in a rubber/polyvinyl chloride weight ratio of 70/30 to 30/70. The anti-vibration rubber composition described above.